CN116172501A - Compact confocal dental scanning device - Google Patents

Abstract

Described herein are devices and methods for confocal 3D scanning. The apparatus may include a spatial pattern disposed on a transparent substrate and a light source configured to provide illumination to the spatial pattern and an optical system including projection/imaging optics having one or more lenses and an optical axis. Projection/imaging optics may be scanned to provide depth scanning by moving along the optical axis.

Description

Compact confocal dental scanning device

The present application is a divisional application of PCT national stage application with application date 2018, 1-11, and national application number 201880006862.1.

Cross reference

The present application claims U.S. provisional patent application No. 62445663 filed on 1 month 12 in 2017 and U.S. patent application No. 15895010 entitled "compact confocal dental scanning apparatus (COMPACT CONFOCALDENTAL SCANNING APPARATUS)" filed on 12 month 29 in 2017, which are incorporated herein by reference in their entirety.

The following U.S. patent applications are incorporated by reference in their entirety to the same extent as if each individual publication or patent application was specifically and individually indicated to be incorporated by reference: U.S. patent application Ser. No. 14/741,172 entitled "apparatus for dental confocal imaging (APPARATUS FOR DENTAL CONFOCAL IMAGING)" filed on month 16 of 2015, and U.S. patent application Ser. No. 14/825,173 entitled "confocal imaging apparatus with curved focal surface (CONFOCAL IMAGING APPARATUS WITH CURVED FOCAL SURFACE)" filed on month 13 of 2015.

Incorporation by reference

All publications and patent applications mentioned in this specification are herein incorporated by reference in their entirety to the same extent as if each individual publication or patent application was specifically and individually indicated to be incorporated by reference.

Technical Field

The present invention relates generally to apparatus and methods for three-dimensional (3D) scanning of objects. In particular, the present invention relates to an apparatus and method for three-dimensional (3D) scanning of teeth in a patient's mouth.

Background

Three-dimensional scanning of objects plays a role in many clinical applications. For example, in the field of orthodontics and mouth restorations, three-dimensional (3D) scanning of teeth may provide valuable information for diagnosis and treatment such as dental restorations and orthodontic indications. Confocal 3D scanning is one of the imaging techniques that can provide such information. Confocal microscopy can be used to perform three-dimensional scanning by illuminating and observing a single near-diffraction limited spot, for example, by using a spatial pinhole to eliminate out-of-focus light. Confocal 3D scanning can be used to obtain images without defocus blur and can allow three-dimensional visualization of objects. Other surface topology scanners have been described, but are often relatively bulky and may be uncomfortable or even difficult to use. Us patent No. 8878905 describes a 3D scanner that obtains the 3D geometry of an object using confocal pattern projection techniques. The 3D scanner disclosed therein uses a time-varying pattern (or a segmented light source to equivalently create a time-varying pattern). When the pattern changes in time for a fixed focal plane, the in-focus area on the object will show an oscillating pattern of light and darkness. However, the out-of-focus region will show little or no contrast in the light oscillation.

Accordingly, there is a need to develop devices and related methods for confocal scanning to have more compact dimensions, lighter weight, and lower cost than conventional confocal scanning devices.

Disclosure of Invention

Described herein are devices and methods for confocal 3D scanning of an object, for example, at least a portion of a tooth in a patient's mouth.

For example, described herein are devices for confocal 3D scanning of a subject's teeth. The apparatus may include a confocal illuminator configured to generate confocal illumination of the object. The confocal illuminator may include a spatial pattern disposed on the transparent substrate and a light source configured to provide illumination to the spatial pattern. The apparatus may include an optical system including one or more lenses and having an optical axis. The apparatus may include a depth scan module configured to be movable along the optical axis. The apparatus may further comprise a beam splitter configured to emit a beam of the confocal illuminator to the object and reflect a beam of light returned from the object. The apparatus may include an image sensor configured to receive the light beam returned from the object through the beam splitter. The device may be configured for 3D scanning of at least a portion of an object, for example, intraoral dental 3D scanning of all derivatives for dental restorations and orthodontic indications.

In general, an apparatus for confocal scanning disclosed herein may include a confocal illuminator, e.g., an LED-illuminated transparency confocal illuminator. In general, the apparatus may include an optical system (including projection/imaging optics) configured to illuminate and image the object. The optical system may include a projection and imaging system or subsystem and an illumination subsystem (illumination optics). For example, the projection/imaging optical system may include an optical element (lens) and the same optical path. The apparatus may include a depth scan module that may include a compact linear actuator, such as a Voice Coil Motor (VCM). The device may include a front tip, which may include a 45 degree back heated mirror (back heated mirror).

For example, the portion of the optical system between the beam splitter and the front tip may be configured to be small enough to be disposed entirely in the depth scanning module. Thus, the confocal scanning apparatus may comprise a single opto-mechanical module for imaging and depth scanning. A single opto-mechanical module integrating the optical system and the depth scanning module may achieve relaxed production and assembly tolerances and reduced manufacturing costs. The optical design is suitable for LED illuminated transparencies, which further enables low cost manufacturing. The optical system may further include a reduced number of lenses, e.g., the optical system may include less than 10 lenses, less than 9 lenses, less than 5 lenses, less than 3 lenses, etc., and in any of the devices described herein above, the optical system (e.g., the protection/imaging optical system) may provide an (e.g., 11×) axial magnification of between 5 and 20. Furthermore, due to the simpler configuration, the optical systems disclosed herein may be less sensitive to component errors and thermal variations than conventional confocal optical systems. The apparatus may include an optical system configured for maximum deviation from telecentricity toward the divergent chief ray for a minimum front tip size. The apparatus may have a non-telecentric configuration in object space (object space), for example, where the confocal beam diverges.

In general, the apparatus may further comprise a polarizing beam splitter for confocal coupling. The apparatus may be configured to shift the constant confocal conjugate. The apparatus may further support a monolithic confocal conjugation assembly. In general, confocal scanning devices can be compact, lightweight, and low cost. For example, the device may be more compact (e.g., 2 x, 3 x, or 4 x) and lighter (e.g., 2 x or 3 x) than a typical conventional confocal scanner having the same scanning capabilities. The apparatus may also include a compact high-speed image sensor. For example, the device may be compact and lightweight to be hand-held. The scan speed may be about 5, 10, 20, 50 scans/second or any value therebetween. For example, the scan speed may be about 10 scans/second.

The spatial pattern on the transparent substrate may be static (e.g., not changing over time). The transparent substrate may include a transparent member. The beam splitter may comprise a polarization sensitive beam splitter, wherein the spatial pattern and the transparent substrate are bonded to a first side of the beam splitter, wherein the image sensor is bonded to a second side of the beam splitter perpendicular to the first side to maintain a stable relative position between the image sensor and the spatial pattern.

For example, the confocal illuminator may be configured such that the image of the light source is positioned at the entrance pupil of the optical system. The spatial pattern may be disposed at a conjugate plane of the image sensor such that a relative lateral offset of the image of the object with respect to the spatial pattern is constant for the image sensor. The exit pupil of the optical system may be arranged for maximum deviation from telecentricity towards the divergent chief ray.

The optical system may include a projection subsystem and an imaging subsystem, which may be combined into a projection/imaging system (also referred to as a projection/imaging subsystem), where the projection subsystem and the imaging subsystem share the same optical path between one or more lenses and the beam splitter and the object.

The device may further comprise a front tip. The optical system (projection/imaging optics portion of the system) between the beam splitter and the front tip can be fully integrated into the depth scanning module as a single opto-mechanical module. The front tip may include a fold mirror disposed at 45 degrees to the optical axis. The depth scan module may be configured to be movable as a unit along the optical axis in a range of 0.1mm to 5mm and to have a depth scan range (depth scanning range) between 5mm and 40 mm. The front tip may have a height of less than 20 mm.

Generally, an apparatus for confocal scanning is disclosed herein. The apparatus may include illumination optics including a confocal illuminator configured to produce confocal illumination of the object. The apparatus may further comprise projection/imaging optics configured to project light (e.g., a transparent pattern) onto and image the object; the projection/imaging optics may have an optical axis. The projection/imaging optics (part or subsystem of the optical system) may include one or more lenses and an exit pupil arranged for maximum deviation from telecentricity towards the divergent chief ray. The apparatus may include a depth scan module configured to be movable along the optical axis. The apparatus may include a beam splitter configured to emit a beam of the confocal illuminator to the object and reflect a beam of light returned from the object. The apparatus may further comprise an image sensor configured to receive the beam returned from the object through the beam splitter.

Also described herein are methods for confocal three-dimensional scanning, which may include activating a confocal illuminator configured to generate confocal illumination of an object, the confocal illuminator including a spatial pattern disposed on a transparent substrate and a light source configured to provide illumination to the spatial pattern. The method may include illuminating a spatial pattern, projecting the pattern onto an object, and imaging the object using an optical system including one or more lenses and having an optical axis (e.g., projection/imaging optics). The method may include scanning an object using a depth scanning module configured to be movable along an optical axis. The method may include transmitting light from the confocal illuminator to the object (via projection/imaging optics) through a beam splitter and imaging the light returned from the object using imaging optics (e.g., again via projection/imaging optics), and directing the returned light onto the image sensor using the beam splitter.

The method may include using one or more spatial patterns on the transparent substrate that do not vary in time. For example, the method may include using a spatial pattern in which the transparent substrate is bonded to a spatial pattern on a first side of the beam splitter, wherein the image sensor is bonded to a second side of the beam splitter perpendicular to the first side to maintain a stable relative position between the image sensor and the spatial pattern.

The method may include providing an image of the light source at an entrance pupil of the optical system (after passing through the transparent pattern). For example, the method may include providing a spatial pattern at a conjugate plane of the image sensor such that a relative lateral offset of the image of the object with respect to the spatial pattern is constant for the image sensor. The method may include setting an exit pupil of the optical system for maximum deviation from telecentricity towards the divergent chief ray. The method may include scanning the object by moving the depth scan as a unit along the optical axis in a range of 0.1mm to 5mm to have a depth scan range of between 5mm and 40 mm.

As described above, described herein is a handheld device for confocal (three-dimensional) scanning. These devices (apparatus, systems, etc.) may be compact and lightweight, and may include LED-based emitters that provide reduced speckle noise. These devices can be used without the need for precise alignment (pre-alignment) with a maximum alignment error of about 0.5 microns or less, unlike other systems where point arrays are used to provide confocal imaging. By using a continuous pattern rather than an array of dots, the confocal arrangement described herein above can be operated without such precise alignment. As described herein above, a simple transparency may replace the dot array used in other systems. In general, these devices may require significantly fewer components than prior art devices; the devices described herein may eliminate the need for one or more of the following: laser, color capture auxiliary illumination and light delivery thermal defogging devices. Furthermore, the devices described herein may have a reduced number of lenses (e.g., fewer lenses are required compared to the prior art). Thus, a compact projection/imaging optical system may allow for a very compact device and may be used in particular with a small axial actuator such as a compact Voice Coil Motor (VCM).

The resulting optical structure may be simpler and less sensitive to component errors and thermal variations than prior art devices. In addition, these devices may be suitable for direct color implementation without the need for separate illumination and dichroic filters.

For example, described herein is a handheld device for confocal scanning, which may include: a light source (e.g., one or more LEDs, including a white light LED and/or a light collector and/or homogenizer); a transparent member having a spatial pattern disposed thereon and configured to be irradiated by the light source; a beam splitter (e.g., a polarizing beam splitter) having a first surface and a second surface and an image sensor on the second surface; an imaging optical system (which may alternatively be referred to as a projection/imaging optical subsystem in some variations) comprising an optical gain and focusing lens and an exit pupil, the imaging optical system having an optical axis; a tip front portion (e.g., a hollow tip front portion) extending from the imaging optical system in the optical axis and including a fold mirror at a distal end of the hollow tip front portion, wherein there is no optical surface between the exit pupil and the fold mirror on the optical axis; and an axial scanner coupled to the imaging optical system and configured to move the imaging optical system in the optical axis relative to the fold mirror.

Unlike prior art devices, the projection/imaging optics may be configured to provide a deviation from telecentricity of the chief ray between the projection/imaging optics and the fold mirror of between 3 and 10 degrees relative to the scan field size. It was previously thought (see, for example, U.S. patent No. 8878905) that the optical system of the scanner should be substantially telecentric (e.g., have an angle of less than 3 degrees, preferably much less than 3 degrees) in the space of the object being detected (scanned object). In contrast, the devices described herein may be non-telecentric, e.g., may deviate from telecentricity by a predetermined amount (e.g., between 3 degrees and 10 degrees, such as 8.5 degrees). The optical design of the devices described herein may have a light source space that includes non-telecentric aperture imaging such that the entire projection/imaging optics is compact and lightweight enough to be fully axially translated (e.g., by a linear actuator/axial scanner, such as a VCM) to facilitate depth scanning.

For example, the apparatus described herein may include an integrated projection/imaging optical system that is moved entirely by a driver (such as an axial actuator of a VCM). This is again distinguished from other configurations in which a separate focusing element (which may form part of the imaging optics) is moved separately from the rest of the imaging optics. Typically, the entire imaging optics between the beam splitter and the hollow front tip is fully integrated into a single opto-mechanical module that is movable by the axial scanner.

In any of the devices described herein above, the transparent member may be attached to the first surface of the beam splitter (e.g., to the outer surface) and/or may be integrally formed as a surface in/on the optical axis in the beam splitter. The spatial pattern on the transparent member may be static or time-varying; in some variations, the spatial pattern is not time-varying. The spatial pattern may be formed on or as part of the beam splitter or may be bonded to the first surface of the beam splitter. The transparent member may be coupled to the first surface of the beam splitter and the image sensor coupled to the second surface of the beam splitter perpendicular to the first surface to maintain a stable relative position between the image sensor and the spatial pattern. For example, the beam splitter may be a polarization sensitive beam splitter and the transparent member may be bonded to a first surface of the beam splitter and the image sensor bonded to a second surface of the beam splitter perpendicular to the first surface to maintain a stable relative position between the image sensor and the spatial pattern.

The apparatus (devices, systems, particularly handheld scanners) and methods described herein may be particularly suitable for use with three-dimensional scanning using structured light technology and/or light field technology. The patterns (static and/or time-varying) that may be used with any of these devices and methods may be configured to provide structured light imaging by projecting known patterns (e.g., grids, lines, bars (e.g., horizontal bars), arrays, etc.) and analyzing the manner in which the patterns deform upon striking the target surface. The above-described apparatus may calculate depth and surface information of object(s) in the scene. Thus, any of these devices may be configured as structured light 3D scanners (structured light 3D scanners). In some variations, the wavelengths of light used may be different, and different light patterns corresponding to different wavelengths may be applied. For example, visible light and/or infrared light may be used. Any of these devices may be configured as "invisible" or "imperceptible" structured light devices, where structured light is used synchronously or simultaneously without interfering with imaging at different frequencies. For example, infrared light and visible light alternating between two different patterns may be applied and detected at high (including extremely high) frame rates. The patterns may be complementary or opposite (e.g., where dark areas in a first pattern are illuminated in a second pattern). Visible light of a different wavelength may alternatively or in addition to infrared light be used.

The methods and apparatus described herein may also be configured as, or alternatively as, light field technology. Light field imaging (e.g., light imaging (plentoptic imaging)) may capture information about a light field emanating from a scene. Such as the intensity of light in the scene and the direction in which the light rays travel in space. Any of the devices and methods described herein can include a microlens array (e.g., disposed in front of one or more image sensors) to sense intensity, color, and direction information. In any of these devices, the microlens array may be positioned before or after the focal plane of the main lens. Alternatively or additionally, a mask (e.g., a printed film mask) may be used. The patterned mask may attenuate the light rays instead of bending them, and the attenuation may recode the light rays on the 2D sensor. Thus, the device can focus and take conventional 2D photographs at full sensor resolution, while the original pixel values also maintain a modulated 4D light field. The light field may be restored by resetting a tile of the 2D fourier transform of the sensor values to a 4D plane and computing the inverse fourier transform. Full resolution image information may be restored for the in-focus portion of the scene. A broadband mask may be provided at the lens to allow the refocused image at full sensor resolution to be calculated for some surfaces (e.g., diffusely reflective surfaces) including a particular wavelength (e.g., near IR). In general, light field information may be used to estimate three-dimensional (e.g., depth) information from an image.

In any of the apparatus described herein, the apparatus may be configured such that the image of the light source is positioned at an entrance pupil of the projection/imaging optical system. The entrance pupil may be part of the projection/imaging optics, or may be between the projection/imaging optics and the beam splitter, or it may be separate from the projection/imaging optics.

The tip front may be configured to be removable from the rest of the device, which comprises a housing covering the light source, the beam splitter, etc., which may comprise a handle portion with grip and/or user interface (control), such as a button, switch, etc., which may be hollow, in particular along the optical axis between the exit pupil of the projection/imaging optical system and the fold mirror. The tip front may be configured to snap and/or rotate, friction fit, magnetic coupling, etc. to the rest of the device (e.g., the housing). The tip front may be single-use or reusable, including sterilizable (e.g., autoclavable, e.g., formed of a material that may be exposed to temperatures exceeding 100 ℃, including 121 ℃ or higher, without deformation or damage after continuous exposure for more than 15 minutes). Alternatively or additionally, these devices may be configured for use with a removable/disposable sleeve mountable on the front of the tip (including, in some variations, but not all, over an optical outlet at the distal end/side of the tip through which the tooth may be imaged).

In any of the devices described herein above, the fold mirror may comprise a back-heated defogging mirror. The fold mirror may redirect the optical axis of the device out of the side window/exit for imaging the teeth. The fold mirror may be disposed at a 45 degree angle (or an angle between 30 and 60 degrees, between 35 and 55 degrees, between 40 and 50 degrees, etc.) from the optical axis at the distal end of the hollow front tip.

The entire device and/or the hollow front tip may be compact; typically, the dimensions are less than 140mm x 20mm (e.g., length, width, thickness). For example, the hollow front tip portion may be 80mm×16mm or less (length, width, thickness).

Typically, the projection/imaging optical system may be moved axially to scan the object. For example, the projection/imaging optical system may be configured as a unit to be movable in a range of 0.1mm to 5mm along the optical axis, and have a depth scanning range of between 5mm to 40 mm.

As described above, the hollow front tip may have a height of 20mm or less (e.g., 20mm or less, 17mm or less, 16mm or less, 15mm or less, 14mm or less, 13mm or less, etc.). The field of view may be between 20×20mm and 12×12mm (e.g., 18×14mm or 14×14mm, etc.).

Thanks to the features described herein, including the spatial pattern incorporating the transparent element on the beam splitter, the device may be relatively lightweight using an integrated projection/imaging optical system and/or with a maximum deviation from telecentricity (e.g. between 3 and 10 degrees) towards the divergent chief ray. For example, the device may have a total weight of 300 grams or less, (e.g., 250g or less, 200g or less, 180g or less, etc.). Furthermore, the projection/imaging optics may be 15mm or less in diameter.

For example, a handheld device for confocal scanning described herein includes: a light source; a transparent member having a spatial pattern disposed thereon and configured to be irradiated by the light source; a beam splitter having a first outer surface and a second outer surface, the transparent member attached to the first outer surface, the image sensor being located on the second outer surface; an integrated projection/imaging optical system including an optical gain, a focusing lens, and an exit pupil, the projection/imaging optical system having an optical axis; a hollow tip front portion extending from the projection/imaging optical system on the optical axis and including a fold mirror at a distal end of the hollow tip front portion, wherein there is no optical surface between the exit pupil and the fold mirror on the optical axis; and an axial scanner coupled to the projection/imaging optical system and configured to move the entire projection/imaging optical system on the optical axis relative to the fold mirror; wherein the projection/imaging optics are configured to provide a deviation from telecentricity of the chief ray between the projection/imaging optics and the fold mirror of between 3 and 10 degrees relative to the scan field size.

Methods for confocal three-dimensional scanning are also described herein. Any of these methods may include using any of the devices for scanning described herein. For example, described herein are methods for confocal 3D scanning, comprising: illuminating a spatial pattern (stationary or moving) located on a first side of a beam splitter, projecting the spatial pattern down along an optical axis, through the beam splitter, and through a projection/imaging optical system (e.g., through a projection/imaging optical subsystem such as an integrated projection/imaging optical system including an optical gain, a focusing lens, and an exit pupil), out of the exit pupil of the projection/imaging optical system, and through a tip front extending from the projection/imaging optical system to a fold mirror at a distal end of the hollow tip front, without passing through an optical surface between the exit pupil and the fold mirror on the optical axis; projecting a spatial pattern onto a target (e.g., a tooth or other dental target); transmitting light (e.g., reflected light, fluorescent light, etc.) from a target back and through the hollow tip, into the projection/imaging optics, and through the beam splitter, into the image sensor on the second side of the beam splitter; and scanning the object by axially moving the entire projection/imaging optical system on the optical axis relative to the fold mirror; wherein the projection/imaging optics are configured to provide a deviation from telecentricity of the chief ray between the projection/imaging optics and the fold mirror of between 3 and 10 degrees relative to the scan field size.

The scanning may be performed by moving the entire projection/imaging optical system as a unit along the optical axis, for example, in a range between 0.1mm and 5mm, to perform the scanning at a depth of a scanning range between 5mm and 40 mm. Any suitable scan rate may be used, including scanning at a speed of 10Hz or higher (e.g., 15Hz, 20Hz, etc.).

In general, the spatial pattern may be any suitable pattern, including a pattern that varies with time or that does not vary with time.

Illuminating the spatial pattern may include illuminating a transparent member coupled to a first side of the beam splitter. The image sensor may be coupled to a second side of the beam splitter perpendicular to the first side to maintain a stable relative position between the image sensor and the spatial pattern. Any of these methods may further comprise disposing the spatial pattern at a conjugate plane of the image sensor such that a relative lateral offset of the image of the object with respect to the spatial pattern is constant for the image sensor.

The methods described herein may also include disposing an image of the light source at an entrance pupil of the optical system.

Any of these methods may further include setting an exit pupil of the optical system toward a maximum deviation of the divergent chief ray from telecentricity.

Generally, the methods described herein above may include determining the confocal position by maximum correlation.

Drawings

The novel features of the invention are set forth with particularity in the appended claims. A better understanding of the features and advantages of the present invention will be obtained by reference to the following detailed description that sets forth illustrative embodiments, in which the principles of the invention are utilized, the accompanying drawings of which:

fig. 1 schematically illustrates one example of a compact device for 3D confocal scanning of an object as described herein.

Fig. 2 schematically shows an example of a compact device for 3D confocal scanning of an object (in this example, the light source is configured to illuminate a pattern on the transparency in kohler illumination mode).

Fig. 3A schematically illustrates an apparatus for confocal scanning, such as the depth scan module of the apparatus shown in fig. 1, in a near focus position.

Fig. 3B schematically illustrates an apparatus for confocal scanning, such as the depth scanning module of the apparatus shown in fig. 1, in a mid-focus position.

Fig. 3C schematically illustrates an apparatus for confocal scanning, such as the depth scanning module of the apparatus illustrated in fig. 1, in a far focus position.

Fig. 4A shows an example of a compact device for confocal scanning, which includes a hollow front tip having an 18 x 14mm field of view (FOV), as described herein. It should be noted that the dimensions are provided for illustration purposes only.

Fig. 4B shows an example of a compact device for confocal scanning, which includes a hollow front tip having a 14 x 14mm field of view (FOV), as described herein. It should be noted that the dimensions are provided for illustration purposes only.

Fig. 5 schematically illustrates the non-telecentricity of an optical system of a compact device for confocal 3D scanning as described herein.

Fig. 6 schematically shows an example of a confocal focal plane module of an apparatus for confocal scanning, wherein the transparent member and the image sensor are directly coupled to the beam splitter or mounted on a fixture relative to the beam splitter.

Fig. 7A illustrates an example of a disordered spatial pattern that may be used as part of a compact device for 3D confocal scanning as described herein.

Fig. 7B illustrates an example of an ordered spatial pattern that may be used as part of a compact device for 3D confocal scanning as described herein.

Fig. 8 shows an example of a method for confocal three-dimensional scanning as described herein.

Detailed Description

The present invention is described in detail below with reference to the accompanying drawings. The present invention may be embodied in various forms and should not be construed as limited to the example embodiments set forth herein.

Compact devices for confocal 3D scanning are described herein. These devices may include a confocal illuminator configured to generate confocal illumination of the object. The confocal illuminator may include a spatial pattern disposed on a transparent substrate (transparency) and a light source configured to provide illumination to the spatial pattern such that it may be projected onto an object. The apparatus may include an optical system (including projection/imaging optics) including one or more lenses and having an optical axis. The apparatus may further comprise illumination optics for illuminating the pattern/spatially patterned transparent member. The apparatus may include an axial scanner (e.g., a depth scanning module) configured to move the projection/imaging optical system along the optical axis. The apparatus may include a beam splitter configured to transmit light from the light source (after passing through the pattern) to the object and reflect light returned from the object onto the imaging sensor. Thus, the apparatus may include an image sensor configured to receive light returned from the object (via projection/imaging optics) via the beam splitter. The device may be configured for 3D scanning of at least a portion of an object, for example, intraoral dental 3D scanning of all derivatives for dental restorations and orthodontic indications.

The apparatus for confocal scanning disclosed herein may include a confocal illuminator, e.g., a LED-illuminated transparent confocal illuminator. The apparatus may include an optical system configured to project light through a transparent member (e.g., a pattern) onto an object and image the object. The optical system may include a projection/imaging system or subsystem that includes projection optics and imaging optics. For example, the projection optics and the imaging optics may be configured to share the same optical element (lens) and the same optical path. The apparatus may include a depth scanning module that includes a compact linear actuator, such as a Voice Coil Motor (VCM). The device may include a front tip, which may include a 45 degree back-heated defogging fold mirror. The optical system between the beam splitter and the front tip may be configured to be small enough to be disposed entirely into the depth scanning module. Thus, the confocal scanning apparatus may comprise a single opto-mechanical module for projection, imaging and depth scanning. A single opto-mechanical module integrating the optical system and the depth scanning module may achieve relaxed production and assembly tolerances and reduced manufacturing costs. The optical design may be suitable for LED illuminated transparencies, which further enables low cost manufacturing. Thus, the optical system may further reduce the number of lenses compared to other confocal scanning systems, e.g., the optical system may include less than 10 lenses, less than 9 lenses, less than 5 lenses, less than 3 lenses, etc. Furthermore, due to the simpler configuration, the optical systems disclosed herein may be less sensitive to component errors and thermal variations than conventional confocal optical systems. The apparatus may include an optical system configured to deviate from telecentricity toward a desired direction of divergent chief rays for a minimum front tip size. The apparatus may have a non-telecentric configuration in image and source space.

The apparatus may also include a polarizing beam splitter as part of the confocal coupling. The apparatus may be configured for a constant offset confocal conjugation. The apparatus may further support a monolithic confocal conjugation assembly.

Typically, these devices may include an integrated projection/imaging optical system, where the entire projection/imaging optical system (e.g., projection/imaging optical subsystem) is moved axially to scan (rather than just a focusing lens). Although moving the entire composite projection/imaging optical system to scan is somewhat counter intuitive, it may be beneficial to reduce the overall size of the device, particularly in combination with the projected spatial pattern and the following configuration: in this configuration, the chief ray between the projection/imaging optical system and the fold mirror deviates from telecentricity by between 3 and 10 degrees with respect to the scanning field size in this system. Due to the features described herein, these devices may be more compact (e.g., 2 x, 3 x, or 4 x) and lighter (e.g., 2 x or 3 x) than typical conventional confocal scanners with the same scanning capabilities. For example, the device may be compact and lightweight for hand-holding. The device may also include a compact high-speed image sensor. The scan speed may be about 5, 10, 20, 50 scans/second or any value therebetween. For example, the scan speed may be about 10 scans/second.

Fig. 1 schematically shows one example of a compact device 100 for confocal scanning of an object. The apparatus may include a confocal illuminator 101 (light source and/or illumination optics) configured to produce confocal illumination that may be projected onto an object. The device may include a spatial pattern, such as transparent member 105 or a transparent glass plate, disposed on a transparent substrate. The light source and any illumination optics may be configured to provide illumination through the spatial pattern and may include a light collector/reflector. For example, the light source may be an LED light source (e.g., with a reflector behind it to direct light through the pattern). Conventional confocal array light sources, such as laser diodes, may be replaced by LED light sources. For example, the apparatus may include an LED-based emitter, which may reduce speckle noise. The spatial pattern may comprise an array of segments for achieving spot illumination. The apparatus may further comprise a light collector or light homogenizer to produce uniform illumination across the pattern. The apparatus may further comprise a condensing lens to condense the light beam of the light source. The apparatus may include a ready-to-use color model capturing and rendering white light LED light sources, which may enable simple color implementation.

The apparatus may include a beam splitter 109 and an image sensor 111. The beam splitter may be configured to transmit the beam of the confocal illuminator to the object and reflect the beam returned from the object to the image sensor. The image sensor 111 may be configured to receive the light beam returned from the object. For example, the beam splitter may be a Polarizing Beam Splitter (PBS).

The apparatus may include an optical system (including projection/imaging optics/subsystem 115, or consisting of projection/imaging optics/subsystem 115) that includes one or more lenses (e.g., focusing optics 119) and an exit pupil 121. The optical system may be configured to project light through the transparent member 105 onto an object and image the object to an image sensor. For example, as shown in fig. 2, the LED light source may be configured to illuminate the transparency in a kohler illumination mode such that an image of the LED falls on the entrance pupil of the optical system. Light exiting imaging optics 115 (including the exit pupil) may pass through hollow front tip 123 until reaching fold mirror 125 near the distal end of front tip 123 and be directed out the tip to an object (e.g., a tooth); the light returning from the object propagates the same path. Typically, the front tip is hollow and the entire imaging optical system moves relative to the front tip (e.g., there is no additional optical surface in the front tip between the axially movable imaging optical system and the fold mirror).

Similar to fig. 1, referring to fig. 2, an optical system is shown that includes a light source 201 (and may also include imaging optics such as a condenser lens 203 in this example) and an optical system 207 (which may include a projection/imaging system, for example). For example, the illumination subsystem may be configured to illuminate a pattern (e.g., transparent piece 209) and such spatial pattern 209 may be projected onto the object. The illuminated object may be returned and imaged by the imaging subsystem 207. The imaging subsystem may be the same as the projection/imaging subsystem between the beam splitter and the fold mirror. As shown in fig. 1, the imaging path and the projection path may share the same optical path and the same optical element, such as one or more lenses. Thus, the object may be imaged back through the same optical system, and light reflected from the object may be directed onto the image sensor through the beam splitter. The imaging subsystem and the projection subsystem may be different in a conventional confocal system, while unlike a conventional confocal optical system, the apparatus for confocal scanning disclosed herein may be smaller, lighter, and less costly than a conventional confocal optical system.

As shown in fig. 1, the imaging optics may be mounted on a depth scanning module (axial scanner 135). For example, the optical system between the beam splitter and the front tip may be fully integrated and coupled to the depth scanning module for axial movement relative to the front tip. The optical system (and in some variations, the depth scanning module) may be integrated into a single optomechanical module as shown in fig. 1, which may enable relaxed production and assembly tolerances. The axial scanner may include a linear axial actuator that may axially translate the optical system in a controlled manner, e.g., over 0.5mm to 3mm, to facilitate depth scanning. The device may be configured with high axial magnification to achieve a simple depth-scanning linear actuator. The axial magnification from the transparency to the object space being scanned may be between 4 x and 30 x, for example between 5 x and 12 x. With the above translation range and magnification range, the optical periodic translation may produce object spatial depth scan coverage in the range of 10mm to 36 mm. Fig. 3A-3C schematically illustrate axial scans of the apparatus for confocal scanning in a near focus position (fig. 3A), a mid focus position (fig. 3B) and a far focus portion (fig. 3C), respectively, showing translation of the entire imaging optics 307, including projection/imaging optics 305. The projected spatial pattern 301 is transmitted onto/into the object and the reflected light is received by the sensor 303 for analysis to determine the 3D surface of the object.

An optical system comprising a combined projection/imaging subsystem may result in a simple projection optics (focusing optics) and projection/imaging optics design and a reduced number of optical elements such as optical lenses. Projection optics may refer to the same optics as imaging optics except in the projection direction (e.g., from the light source onto the object). For example, the optical system may include fewer than 10, 9, 5, or 3 optical elements. For example, the diameter of the optical lens in an optical system may be about 5mm, 8mm, 10mm, 14mm, 15mm, or any value therebetween, while the optical lens in a conventional confocal optical system may have a diameter of about 25 mm. For example, the optical system disclosed herein further reduces the following elements in a typical conventional confocal scanning apparatus: such as dichroic filters, microlenses, etc. The apparatus for confocal scanning disclosed herein is more compact, lighter in weight and less costly than conventional confocal scanning apparatuses. For example, in some embodiments, the device may have a weight of about 100, 200, or 300 grams. For example, in some implementations, the device may have dimensions less than 150mm x 25mm, 140mm x 20mm, or 130mm x 14 mm.

Fig. 4A schematically shows an apparatus for compact confocal scanning, which includes a hollow front tip having a 18 x 14mm field of view (FOV). Fig. 4B shows an apparatus for compact confocal scanning, which includes a hollow front tip having a 18 x 14mm field of view (FOV). As shown in fig. 4A and 4B, the apparatus for compact confocal scanning may have a smaller front tip size than a conventional confocal scanning apparatus. The device may have a front tip height of about 14mm with a FOV of 14 x 14mm. The hollow front tip may include a back-heated defogging fold mirror. For example, in some embodiments, the hollow tip may have dimensions of about 90mm x 20mm, 80mm x 16mm, or 60mm x 14mm. These dimensions are for illustration only and other dimensions may be used.

In general, any of the devices described herein may be non-telecentric. In particular, the projection/imaging optical system may be configured to provide a deviation from telecentricity of the chief ray between the projection/imaging optical system and the fold mirror, which is between 3 degrees and 10 degrees, with respect to the scan field size. Fig. 5 schematically shows an example of a non-telecentric optical system of an apparatus for confocal scanning in one embodiment of the invention. The optical system may be configured with light source-space non-telecentric aperture imaging such that the optical system is sufficiently compact and lightweight to facilitate depth scanning, for example, by axial translation through a linear actuator such as a Voice Coil Motor (VCM). The exit pupil of the optical system may be positioned for maximum deviation from telecentricity towards the divergent chief ray, which may enable a minimum size of the front tip of the device. The scanned field of view size may be the same for all design options for a particular distance from the tip, e.g., a mid-range of scan depths. The angle of departure from telecentricity may be determined by the exit pupil distance from the object focus and the field of view size. The tip height may be derived from the trajectory of the beam of the light source on the fold mirror. The height may be smaller as the exit pupil becomes closer to the object focus (exit pupil forward). The angle of departure from telecentricity may range from about 3 degrees to about 10 degrees. For example, in some embodiments, the angle of departure from telecentricity may be about 8.5 degrees. The angle of departure from telecentricity is a range of fields in the folding plane of the mirror that has an effect on the tip height.

Fig. 6 schematically illustrates an example of a confocal illuminator of an apparatus for confocal scanning, wherein in one embodiment a transparent member (including a spatial pattern) is directly coupled to a beam splitter or mounted on a fixed apparatus relative to the beam splitter. As shown in fig. 6, the transparent member may be directly bonded to one face of the beam splitter (e.g., polarizing beam splitter, PBS) and the image sensor may be bonded to the other face of the beam splitter (e.g., second face) perpendicular to the transparent member, thus maintaining a stable relative position between the image sensor and the transparent member ("confocal condition"). The apparatus may be configured to shift the constant confocal conjugate. The transparent member and the image sensor may be disposed on a conjugate plane of the object. The apparatus may also support a monolithic confocal conjugation assembly. The illumination-based pattern enables conjugate imaging on the image sensor, which is invariant to relative lateral shifts. The means for confocal scanning may be configured to have a position-invariant correlation that is less sensitive to assembly shifts.

Fig. 7A and 7B illustrate examples of spatial patterns that may be used as part of any compact device for 3D confocal scanning described herein. Fig. 7A shows an example of a disordered pattern of an apparatus for confocal scanning. Fig. 7B shows an example of an ordered pattern of an apparatus for confocal scanning. The means for confocal scanning may include an illuminated pattern instead of an array of light beams in a conventional confocal scanning device. For example, a white LED back-illuminated pattern may be used to achieve confocal imaging. Various patterns can be used in the confocal illuminator, which enables design flexibility and lower signal requirements. For example, the pattern may include an array of segments to achieve equivalent spot illumination. The illumination point passing through the pattern may be near diffraction limited. For example, the pattern may comprise an array of segments having a size similar to the size of a pinhole in a conventional confocal microscope. For example, the pattern may comprise an array of fragments having a diameter of about 1 μm, 10 μm, 25 μm, 50 μm, 1mm or 2mm or any value therebetween.

For example, the means for confocal scanning may further comprise an array of detection pinholes. For example, the detection pinhole may be provided in a fixture between the beam splitter and the image sensor. For example, the detection pinholes may be incorporated or integrated in the image sensor. For example, the size of the pinhole may be configured to suit the Numerical Aperture (NA) of the optical system and the wavelength of the light source. For example, the size of the detection needle hole may be further adapted to the magnification of the optical system.

The confocal position may be determined by the maximum correlation. For example, the reference pattern position may be unchanged. For example, a depth position per pixel or group of pixels of the image sensor may be specified that corresponds to a maximum signal obtained over the pixel or group of pixels after the depth scan. The lateral resolution need not be compromised because all pixels within a region of interest (ROI) can be used. For example, resolution may be improved by sub-pixel processing.

Methods for confocal 3D confocal three-dimensional scanning sizing are also described herein. Generally, the method may include activating a confocal illuminator configured to generate confocal illumination of the object. The method may include using a confocal illuminator comprising a spatial pattern disposed on a transparent substrate, a light source configured to provide illumination to the spatial pattern, and/or any additional illumination optics (e.g., lenses).

The method may include illuminating a pattern, projecting the pattern onto an object, and imaging the object through an optical system including projection/imaging optics including one or more lenses and having an optical axis. The method may include scanning the object by a depth scanning module configured to be movable along an optical axis. The method may include projecting a beam of light from a confocal illuminator onto an object through a beam splitter, and directing light returned from the object onto an imaging sensor using the beam splitter.

For example, the method may include using a time-invariant spatial pattern on the transparent substrate. For example, the method may include using a spatial pattern and a transparent substrate, wherein the pattern (e.g., a transparent member) is bonded to a first side of the beam splitter, further wherein the image sensor is bonded to a second side of the beam splitter perpendicular to the first side, to maintain a stable relative position between the image sensor and the spatial pattern.

A method may include disposing an image of a light source at an entrance pupil of an optical system. For example, the method may include disposing the spatial pattern at a conjugate plane of the image sensor such that a relative lateral offset of the image of the object with respect to the spatial pattern is constant for the image sensor. For example, the method may include arranging the exit pupil of the optical system towards a maximum deviation of the divergent chief ray from telecentricity.

A method may include arranging a scanned object comprising moving a depth scanning module as a unit along an optical axis in a range of 0.1mm to 5mm to obtain a depth scanning range of between 5mm and 40 mm. For example, the method may include determining the confocal position by maximum correlation.

As briefly discussed above, the apparatus and methods described herein may also be configured as a structured light scanning system and/or a light field 3D reconstruction system. For example, in some variations, light field data may be captured, such as by configuring the imaging system as an all-optical device (plenotoptic apparatus), such as by including a plurality of microlenses before or after the focal plane of the main lens subsystem (e.g., compact focusing optics). Thus, in some variations, the light may pass through an optical surface (microlens) between the exit pupil and the fold mirror in the optical axis, or the microlens may come from a portion of the compact focusing optics. A depth map may be created from the light field data, and this depth map may be used to create a surface. Conventional stereoscopic imaging methods may be used for depth map extraction, or depth data may be extracted from a light field camera by combining two or more depth estimation methods.

Fig. 8 illustrates another example of a method as described herein. In fig. 8, a method for confocal three-dimensional scanning includes: the spatial pattern on the first side of the beam splitter is first illuminated and projected down the optical axis through the beam splitter, through an integrated projection/imaging optical system comprising an optical gain and focusing lens and an exit pupil, out of the exit pupil and through a hollow tip front extending from the projection/imaging optical system to a fold mirror at the distal end of the hollow tip front, without passing through an optical surface between the exit pupil and the fold mirror in the optical axis 801. The method then includes projecting a spatial pattern onto the target 803 and transmitting reflected light from the target back into and through the hollow tip into the projection/imaging optical system, through the beam splitter and into the image sensor on the second side of the beam splitter 805. The method may further include scanning the target by axially moving the entire projection/imaging optical system on the optical axis relative to the fold mirror 807, wherein the projection/imaging optical system is configured to provide a deviation from telecentricity of the chief ray between the projection/imaging optical system and the fold mirror relative to the scan field of view size, the deviation being between 3 degrees and 10 degrees.

The systems, devices, and methods of the preferred embodiments and variations thereof may be at least partially embodied and/or implemented as a machine configured to receive a computer-readable medium storing computer-readable instructions. The instructions are preferably executed by a computer-executable component preferably integrated with a system comprising a computing device configured with software. The computer readable medium may be stored on any suitable computer readable medium, such as RAM, ROM, flash memory, EEPROM, an optical device (e.g., CD or DVD), a hard disk drive, a floppy disk drive, or any suitable device. The computer-executable components are preferably general-purpose or special-purpose processors, but any suitable special-purpose hardware or hardware/firmware combination may alternatively or additionally execute the instructions.

When a feature or element is referred to herein as being "on" another feature or element, it can be directly on the other feature or element or intervening features and/or elements may also be present. In contrast, when a feature or element is referred to as being "directly on" another feature or element, there are no intervening features or elements present. It will also be understood that when a feature or element is referred to as being "connected," "attached," or "coupled" to another feature or element, it can be directly connected, attached, or coupled to the other feature or element, or intervening features or elements may be present. In contrast, when a feature or element is referred to as being "directly connected," "directly attached," or "directly coupled" to another feature or element, there are no intervening features or elements present. Although described or illustrated with respect to one embodiment, the features and elements so described or illustrated may be applied to other embodiments. It will also be appreciated by those of skill in the art that references to a structure or feature that is disposed "adjacent" another feature may have portions that overlap or underlie the adjacent feature.

The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. For example, as used herein, the singular forms "a", "an" and "the" include plural referents unless the context clearly dictates otherwise. It will be further understood that the terms "comprises" and/or "comprising," when used in this specification, specify the presence of stated features, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, steps, operations, elements, components, and/or groups thereof. As used herein, the term "and/or" includes any and all combinations of one or more of the associated listed items, and may be abbreviated as "/".

Spatially relative terms, such as "under," "beneath," "downward," "above," "upward," and the like, may be used herein for ease of description to describe one element or feature's relationship to another element or feature as illustrated in the figures. It will be understood that the spatially relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. For example, if the device in the figures is turned over, elements described as "below" or "beneath" other elements or features would then be oriented "above" the other elements or features. Thus, the exemplary term "upper and lower" may include directions "above" and "below. The device may be otherwise oriented (rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein interpreted accordingly. Similarly, the terms "upward," "downward," "vertical," "horizontal," and the like are used herein for purposes of explanation only, unless specifically indicated otherwise.

Although the terms "first" and "second" may be used herein to describe various features/elements (including steps), these features/elements should not be limited by these terms unless otherwise indicated by the context. These terms may be used to distinguish one feature/element from another feature/element. Thus, a first feature/element discussed below could be termed a second feature/element, and, similarly, a second feature/element discussed below could be termed a first feature/element, without departing from the teachings of the present invention.

Throughout the specification and the claims which follow, unless the context requires otherwise, the word "comprise" and variations such as "comprises" and "comprising" will mean that various components (e.g. compositions and devices including devices and methods) may be used in common in methods and articles. For example, the term "comprising" will be understood to imply the inclusion of any stated element or step but not the exclusion of any other element or step.

In general, any of the apparatus and methods described herein should be understood to be inclusive, but that all or a subset of the components and/or steps may alternatively be exclusive, and may be expressed as "consisting of" or, alternatively, "consisting essentially of" the various components, steps, sub-components, or sub-steps.

As used herein in the specification and claims, including as used in the examples and unless otherwise specifically indicated, all numbers may be read as prefixed by the word "about" or "approximately", even if the term does not expressly appear. The phrase "about" or "approximately" may be used when describing a size and/or position to indicate that the described value and/or position is within a reasonably expected range of values and/or positions. For example, a value may have +/-0.1% of the value (or range of values), +/-1% of the value (or range of values), +/-2% of the value (or range of values), +/-5% of the value (or range of values), +/-10% of the value (or range of values), etc., any value given herein should also be understood to include about or approximately the value unless the context indicates otherwise. For example, if the value "10" is disclosed, then "about 10" is also disclosed. Any numerical range recited herein is intended to include all sub-ranges subsumed therein. It will also be understood that when a value is disclosed, then "less than or equal to" the value, "greater than or equal to" the value, and possible ranges of values therebetween, are also disclosed, as will be appreciated by those of skill in the art. For example, if the value "X" is disclosed, then "less than or equal to X" and "greater than or equal to X" are also disclosed (e.g., where X is a numerical value). It should also be understood that throughout this application, data is provided in a variety of different formats, and that the data represents ranges of endpoints and starting points, and any combination of the data points. For example, if a particular data point "about 10" and a particular data point "about 15" are disclosed, it is understood that greater than, greater than or equal to, less than or equal to 10 and 15, and between 10 and 15. It should also be understood that each unit between two particular units is also disclosed. For example, if 10 and 15 are disclosed, 11, 12, 13 and 14 are also disclosed.

While various illustrative embodiments have been described above, any of a number of modifications may be made to the various embodiments without departing from the scope of the invention as described in the claims. For example, in alternative embodiments, the order in which the various described method steps are performed may generally be changed, and in other alternative embodiments, one or more method steps may be skipped entirely. Optional features of the various device and system embodiments may be included in some embodiments and not others. Accordingly, the foregoing description is provided for the purpose of illustration only and should not be construed as limiting the scope of the invention as set forth in the following claims. By way of illustration and not limitation, the examples and illustrations contained herein show specific embodiments in which the subject matter may be practiced. As mentioned, other embodiments may be utilized and derived therefrom, such that structural and logical substitutions and changes may be made without departing from the scope of this disclosure. Such embodiments of the inventive subject matter may be referred to herein, individually or collectively, by the term "invention" merely for convenience and without intending to voluntarily limit the scope of this application to any single invention or inventive concept if more than one is in fact disclosed. Thus, although specific embodiments have been illustrated and described herein, any arrangement calculated to achieve the same purpose may be substituted for the specific embodiments shown. This disclosure is intended to cover any and all adaptations or variations of various embodiments. Combinations of the above embodiments, and other embodiments not specifically described herein, will be apparent to those of skill in the art upon reviewing the above description.

Claims (10)

1. A handheld device for intraoral scanning, the handheld device comprising:

a light source;

a transparent member having a spatial pattern disposed thereon;

a beam splitter having a first outer surface and a second outer surface, the transparent member attached to the first outer surface, the image sensor being located on the second outer surface;

a single movable opto-mechanical module comprising an integrated projection/imaging optical system comprising focusing optics and an exit pupil, the projection/imaging optical system having an optical axis, wherein the projection/imaging optical system of the handheld device is fully integrated into the single movable opto-mechanical module;

a hollow front tip extending from the projection/imaging optical system on the optical axis and including a fold mirror at a distal end of the hollow front tip, wherein there is no optical surface between the exit pupil and the fold mirror on the optical axis; and

an axial scanner coupled to the projection/imaging optical system and configured to move a single movable optomechanical module comprising the entirety of the projection/imaging optical system on the optical axis relative to the fold mirror;

Wherein the projection/imaging optics are configured to provide a deviation of a chief ray between the projection/imaging optics and the fold mirror from telecentricity, the deviation being between 3 degrees and 10 degrees, relative to a scan field size;

wherein the transparent member is configured to be illuminated by the light source and output pattern light comprising a spatial pattern, the pattern light passing through the beam splitter and onto an object external to the device; and is also provided with

Wherein the image sensor is configured to receive reflected pattern light that has been reflected by the object and directed back through the beam splitter.

2. A method for three-dimensional scanning of teeth in a patient's mouth, the method comprising:

illuminating a spatial pattern on a first side of a beam splitter and projecting the spatial pattern down along an optical axis, passing the spatial pattern through the beam splitter, through an integrated projection/imaging optical system comprising focusing optics and an exit pupil, out of the exit pupil, and through a hollow front tip extending from the projection/imaging optical system to a fold mirror at a distal end of the hollow front tip without passing through an optical surface between the exit pupil and the fold mirror on the optical axis, wherein the projection/imaging optical system is fully integrated into a single movable opto-mechanical module;

Projecting the spatial pattern onto a target;

transmitting reflected light from the target back through the hollow front tip, into the projection/imaging optical system, through the beam splitter, and into an image sensor on a second side of the beam splitter; and

scanning the object by axially moving the single movable opto-mechanical module comprising the projection/imaging optical system as a whole on the optical axis relative to the fold mirror,

wherein the projection/imaging optics are configured to provide a deviation of a chief ray between the projection/imaging optics and the fold mirror from telecentricity, the deviation being between 3 degrees and 10 degrees, relative to a scan field size.

3. An apparatus for dental scanning, comprising:

a light source for emitting light;

an illuminator, the illuminator comprising:

a beam splitter having a first surface and a second surface;

a transparent member directly bonded to the first surface of the beam splitter, the transparent member including a spatial pattern disposed thereon, wherein the transparent member is configured to be illuminated by light from the light source and to output pattern light including the spatial pattern through the beam splitter, wherein the pattern light is to be output onto an object external to the dental scanning apparatus;

An image sensor coupled to the second surface of the beam splitter, wherein the image sensor is configured to receive reflected pattern light that has been reflected from the object and directed back through the beam splitter, wherein the image sensor maintains a stable relative position with respect to the spatial pattern of the transparent member due to the transparent member being directly coupled to the first surface of the beam splitter and the image sensor being coupled to the second surface of the beam splitter; and

an optical system comprising one or more lenses, the optical system directing the pattern light onto the object and directing reflected pattern light reflected back from the object through the beam splitter and to the image sensor.

4. An assembly for a dental scanning apparatus, comprising:

a beam splitter having a first surface and a second surface;

a transparent member directly bonded to the first surface of the beam splitter, the transparent member including a spatial pattern disposed thereon, wherein the transparent member is configured to be illuminated by light from a light source of the dental scanning apparatus and output pattern light including the spatial pattern, the pattern light passing through the beam splitter and onto an object external to the dental scanning apparatus; and

An image sensor coupled to the second surface of the beam splitter, wherein the image sensor is configured to receive reflected pattern light that has been reflected by the object and directed back through the beam splitter, and wherein the image sensor maintains a stable relative position with respect to the spatial pattern of the transparent member due to the transparent member being directly coupled to the first surface of the beam splitter and the image sensor being coupled to the second surface of the beam splitter.

5. A method of manufacturing an assembly for a dental scanning apparatus, comprising:

directly bonding the transparent member to a first surface of a beam splitter having the first surface and a second surface, the transparent member including a spatial pattern disposed thereon, wherein the transparent member is configured to be illuminated by light from a light source of the dental scanning apparatus and to output pattern light including the spatial pattern, the pattern light passing through the beam splitter and onto an object external to the dental scanning apparatus; and

an image sensor is coupled to the second surface of the beam splitter, wherein the image sensor is configured to receive reflected pattern light that has been reflected by the object and directed back through the beam splitter, and wherein the image sensor maintains a stable relative position with respect to the spatial pattern of the transparent member when used in the dental scanning apparatus due to the transparent member being directly coupled to the first surface of the beam splitter and the image sensor being coupled to the second surface of the beam splitter.

6. An intraoral scanner comprising:

a light source for generating light to be output onto an object external to the intraoral scanner;

a movable opto-mechanical module comprising integrated projection/imaging optics and an exit pupil, the projection/imaging optics having an optical axis, wherein the projection/imaging optics are fully integrated into the movable opto-mechanical module;

an axial actuator coupled to the movable opto-mechanical module and configured to move the movable opto-mechanical module including the projection/imaging optics as a whole on the optical axis to achieve a plurality of focus settings; and

an image sensor configured to receive reflected light that has been reflected from an object external to the intraoral scanner for the plurality of focus settings.

7. An assembly for a dental scanning apparatus, comprising:

a beam splitter having a first surface and a second surface;

a transparent member integrally formed in or on the first surface of the beam splitter, the transparent member including a spatial pattern disposed thereon, wherein the transparent member is configured to be illuminated by light from a light source of the dental scanning apparatus and to output pattern light including the spatial pattern, the pattern light passing through the beam splitter and onto an object external to the dental scanning apparatus; and

An image sensor coupled to the second surface of the beam splitter, wherein the image sensor is configured to receive reflected pattern light that has been reflected by the object and directed back through the beam splitter, and wherein the image sensor maintains a stable relative position with respect to the spatial pattern of the transparent member due to the transparent member being directly coupled to the first surface of the beam splitter and the image sensor being coupled to the second surface of the beam splitter.

8. An intraoral scanner comprising:

a light source for generating light;

a beam splitter having a first surface and a second surface;

a transparent member coupled to the first surface of the beam splitter, the transparent member including a spatial pattern disposed thereon, wherein the transparent member is configured to be illuminated by the light and output pattern light including the spatial pattern, the pattern light passing through the beam splitter and onto an object external to the intraoral scanner;

a movable opto-mechanical module comprising integrated projection/imaging optics and an exit pupil, the projection/imaging optics having an optical axis, wherein the projection/imaging optics are fully integrated into the movable opto-mechanical module;

An axial actuator coupled to the movable opto-mechanical module and configured to move the movable opto-mechanical module including the projection/imaging optics as a whole on the optical axis to achieve a plurality of focus settings; and

an image sensor coupled to the second surface of the beam splitter, wherein the image sensor is configured to receive, for the plurality of focus settings, reflected pattern light that has been reflected by the object and directed back through the beam splitter, and wherein the image sensor maintains a stable relative position with respect to the spatial pattern of the transparent member due to the transparent member being coupled to the first surface of the beam splitter and the image sensor being coupled to the second surface of the beam splitter.

9. A hand-held device for confocal scanning, the device comprising:

a light source;

a transparent member having a spatial pattern disposed thereon and configured to be illuminated by the light source;

a beam splitter having a first surface and a second surface, an image sensor being located on the second surface;

a front tip extending on an optical axis from the projection/imaging optical system and including a fold mirror at a distal end of the front tip;

A single movable opto-mechanical module comprising a non-telecentric projection/imaging optical system comprising a focusing element, one or more lenses, and an exit pupil, the projection/imaging optical system having the optical axis, wherein the projection/imaging optical system is fully integrated into the single movable opto-mechanical module between the beam splitter and the front tip, and wherein the projection/imaging optical system provides a deviation of chief rays between the projection/imaging optical system and the fold mirror from telecentricity of 3 degrees or more relative to a scan field of view size; and

an axial actuator coupled to the projection/imaging optical system and configured to move the single movable optomechanical module on the optical axis relative to the fold mirror, the single movable optomechanical module comprising the projection/imaging optical system as a whole, the projection/imaging optical system comprising the focusing element, the one or more lenses, and the exit pupil, wherein the focusing element is not moved separately from a remainder of the projection/imaging optical system.

10. A method of confocal three-dimensional scanning using a handheld device, the method comprising:

illuminating a spatial pattern disposed on a transparent member attached to a first side of a beam splitter and projecting the spatial pattern down along an optical axis, passing the spatial pattern through the beam splitter, through an integrated projection/imaging optical system that is non-telecentric and that includes a focusing element, one or more lenses, and an exit pupil, out of the exit pupil, and through a front tip extending from the projection/imaging optical system to a fold mirror located at a distal end of the front tip, wherein the integrated projection/imaging optical system provides a deviation of chief rays between the projection/imaging optical system and the fold mirror from telecentric with respect to a scan field size between the beam splitter and the front tip, the deviation being 3 degrees or greater, and wherein the integrated projection/imaging optical system is fully integrated into a single movable optical mechanical module;

projecting the spatial pattern onto a target;

transmitting reflected light from the target back through the front tip, into the projection/imaging optical system, through the beam splitter, and into an image sensor on a second side of the beam splitter; and

The target is scanned by axially moving the single movable opto-mechanical module relative to the fold mirror on the optical axis, the single movable opto-mechanical module comprising the projection/imaging optical system as a whole, the projection/imaging optical system comprising the focusing element, the one or more lenses and the exit pupil, wherein the focusing element is not moved separately from the rest of the projection/imaging optical system.

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