Optical system for collecting distance information within the field

Abstract

The present application relates to an optical system for collecting distance information within a field. An optical system for collecting distance information within a field is provided. The optical system may include a lens for collecting photons from the field, and may include a lens for distributing the photons to the field. The optical system may include a lens for collimating photons passing through an aperture, a filter for rejecting vertically incident light outside an operating wavelength, and a pixel for detecting incident photons. The optical system may also include an illumination source that outputs photons of the operating wavelength.

Description

[0001] This application is a divisional application of an invention patent application with an international application date of June 26, 2017, a national application number of 201780068584.8, and an invention name of “Optical system for collecting distance information within a field”. Technical Field

[0002] The present invention relates generally to the field of optical sensors, and more particularly to novel and useful optical systems for collecting distance information in the field of optical sensors. BRIEF DESCRIPTION OF THE DRAWINGS

[0003] Figure 1 is a schematic representation of the system.

[0004] Figure 2 is a schematic representation of a variation of the system.

[0005] Figure 3 is a schematic representation of a variation of the system.

[0006] Figure 4 is a schematic representation of a variation of the system.

[0007] Figure 5 is a schematic representation of a variation of the system.

[0008] Figure 6 is a schematic representation of a variation of the system.

[0009] Figure 7 is a schematic representation of a variation of the system.

[0010] Figure 8 is a schematic representation of a variation of the system.

[0011] Fig. 9 is a flowchart representation according to a variation of the system.

[0012] Fig.10 is a schematic representation of a variation of the system.

[0013] Fig.11 is a schematic representation of a variation of the system. DETAILED DESCRIPTION

[0014] The following description of the embodiments of the invention is not intended to limit the invention to these embodiments, but to enable those skilled in the art to make and use the invention. The variations, configurations, implementations, example implementations, and examples described herein are optional and are not exclusive to the variations, configurations, implementations, example implementations, and examples they describe. The invention described herein may include any and all permutations of these variations, configurations, implementations, example implementations, and examples.

[0015] 1. One-dimensional optical system: hole array

[0016] like Figure 1 As shown in FIG. 1 , a one-dimensional optical system 100 for collecting distance information within a field includes: an illumination source set 110 arranged along a first axis, each illumination source in the illumination source set 110 being configured to output an illumination beam of an operating wavelength toward a discrete point in the field located in front of the illumination source; a bulk imaging optical device (bulkimaging optic) 130 characterized by a focal plane relative to the field; an aperture layer 140 coinciding with the focal plane, the aperture layer 140 defining an aperture set 144 in a linear array parallel to the first axis and defining a stop region (stop region) around the aperture set 144 a stop region 146, each of the apertures in the aperture set 144 defining a field of view in the field that coincides with a discrete point output by a corresponding illumination source in the illumination source set 110, the stop region 146 absorbing light that is reflected from a surface in the field that is outside the field of view defined by the aperture set 144 and that passes through the volume imaging optical device 130; a lens set 150, each lens in the lens set 150 being characterized by a second focal length, being offset from the focal plane by a second focal length relative to the volume imaging optical device 130, being aligned with an aperture in the aperture set 144, and being configured to collimate light passing through the aperture; and an optical filter. The invention relates to an optical filter 160, which is adjacent to the lens set 150, opposite to the aperture layer 140, and is configured to allow light at a working wavelength to pass therethrough; a pixel set 170, which is adjacent to the optical filter 160, opposite to the lens set 150, each pixel in the pixel set 170 corresponds to a lens in the lens set 150 and includes a sub-pixel set arranged along a second axis that is not parallel to the first axis; and a diffuser 180, which is inserted between the optical filter 160 and the pixel set 170 and is configured to spread the collimated light output from each lens in the lens set 150 on the sub-pixel set of the corresponding pixel in the pixel set 170.

[0017] 1.1 Application

[0018] In general, one-dimensional optical system 100 ("system") functions as an image sensor that collects three-dimensional distance data for a volume occupied by the system while rotating about an axis parallel to the columns of apertures. Specifically, one-dimensional optical system 100 can scan a volume to collect three-dimensional distance data that can then be reconstructed into a virtual three-dimensional representation of the volume, such as based on the recorded time between emission of an illumination beam from an illumination source and detection of photons incident on pixel set 170 that may originate from the illumination source, based on a phase-based measurement technique, or based on any other suitable distance measurement technique. The system 100 includes: an offset array of apertures arranged behind a volume imaging optical device 130 and defining discrete fields of view in the field located in front of the volume imaging optical device 130 (i.e., non-overlapping fields of view beyond a threshold distance from the system); an illumination source set 110 that projects discrete illumination beams at an operating wavelength into (and substantially only into) the field of view defined by the apertures; a lens array that collimates light passing through the corresponding apertures; and a filter 160 that selectively passes a narrow band of light (i.e., electromagnetic radiation) including the operating wavelength; and a pixel set 170 that detects incident photons (e.g., counts incident photons, tracks the time between consecutive incident photons). Thus, the system can selectively project illumination beams into the field located in front of the system according to an illumination pattern that substantially matches the field of view of the aperture in terms of size and geometry over a range of distances from the system. In particular, the illumination source is configured to substantially illuminate only surfaces in the field located in front of the system that can be detected by pixels in the system, so that power output by the system (via the illumination source) is wasted by illuminating surfaces that are not visible to the pixels in the field is minimized. Thus, the system can achieve a relatively high ratio of output signal (i.e., illumination beam power) to input signal (i.e., photons delivered incident on the pixel array). In addition, lens set 150 can collimate light passing through adjacent apertures so that light incident on filter 160 encounters filter 160 at an angle of incidence of approximately 0°, thereby maintaining a relatively narrow band of wavelengths passed by filter 160 and achieving a relatively high signal-to-noise ratio ("SNR") for light reaching pixel set 170.

[0019] The system includes pixels arranged in columns and aligned with the apertures, and the geometry of each pixel can be non-square (e.g., short and wide) so that the sensing area of ​​the system extends the fixed aperture spacing and pixel column height. The system also includes a diffuser 180 that spreads the light from the aperture through the filter 160 over the area of ​​the corresponding pixel so that the pixel can detect incident photons within its entire width and height, thereby increasing the dynamic range of the system.

[0020] The system is described herein as projecting electromagnetic radiation into a field and detecting electromagnetic radiation reflected from a surface in the field back to a bulk receiver optical device. The terms "illumination beam," "light," "ray," and "photon" as used herein refer to such electromagnetic radiation. The term "channel" as used herein refers to an aperture in aperture layer 140, a corresponding lens in lens set 150, and a corresponding pixel in pixel set 170.

[0021] 1.2 Volumetric Imaging Optical Device

[0022] The system includes a volume imaging optics 130 characterized by a focal plane relative to the field. In general, the volume imaging optics 130 is used to project incident light rays from outside the system toward the focal plane, wherein light rays incident on a stop region 146 of the aperture layer 140 are rejected (e.g., mirrored or absorbed) and wherein light rays incident on an aperture in the aperture layer 140 are passed into a lens characterized by a focal length and offset from the focal plane by that focal length.

[0023] In one implementation, the volume imaging optics 130 include a converging lens characterized by a particular focal length at the operating wavelength of the system, such as a biconvex lens ( Figure 2 The volume imaging optical device 130 may also include a plurality of discrete lenses that cooperate to project light toward the aperture layer 140 and are characterized by a composite focal plane relative to the field, such as Fig.11 However, the volume imaging optics 130 may be any other suitable type of lens or combination of lenses of any other type or geometry.

[0024] 1.3 Hole layer

[0025] like Figure 1 and Figure 2As shown in , the system includes an aperture layer 140 that coincides with the focal plane, the aperture layer 140 defining a set of apertures 144 in a linear array parallel to the axis of the illumination source and defining a stop region 146 around the aperture set 144, wherein each aperture in the aperture set 144 defines a field of view that coincides with a discrete point in the field output by a corresponding illumination source in the illumination source set 110, and wherein the stop region 146 absorbs and / or reflects light that is reflected from surfaces in the field that are outside the field of view defined by the aperture set 144 and passes through the volume imaging optical device 130. In general, the aperture layer 140 defines an array of open areas (i.e., apertures, including one aperture for each lens) and closed areas ("stop regions") between adjacent openings. Each aperture in the aperture layer 140 defines a "pinhole" that defines the field of view of its corresponding sensing channel and allows light reflected from external surfaces within its field of view to pass into its corresponding lens, and each stop region 146 can block light incident on a selected area of ​​the focal plane from entering the lens array, as shown in FIG. Figure 6 as shown in .

[0026] The aperture layer 140 includes a relatively thin, opaque structure that is coincident with (eg, disposed along) the focal plane of the volume imaging optical device 130, such as Figure 1 and Figure 2 . For example, the hole layer 140 may include a 10 micron thick copper, silver, or nickel film deposited (e.g., electroplated) on a photocurable transparent polymer and then selectively etched to form an array of holes. In a similar example, a reflective metallization layer or a light absorbing photopolymer (e.g., a photopolymer mixed with a light absorbing dye) may be deposited on a glass wafer and selectively cured using a photomask to form the hole layer 140 and the hole set 144. Alternatively, the hole layer 140 may include a discrete metal film that is mechanically or chemically perforated to form an array of holes, bonded to a lens array, and then mounted above the volume imaging optical device 130 along the focal plane. However, the hole layer 140 may include any other reflective (e.g., mirror reflective) or light absorbing material formed in any other manner to define an array of holes along the focal plane of the volume imaging optical device 130.

[0027] In the one-dimensional optical system 100, the aperture layer 140 may define a single column of a plurality of discrete circular apertures having a substantially uniform diameter, wherein each aperture defines an axis substantially parallel to and aligned with a lens in the lens array, such as Figure 3. Adjacent holes are offset by a hole spacing distance that is greater than the hole diameter and substantially similar to the lens spacing distance, and the hole layer 140 defines a stop region 146 (i.e., an opaque or reflective region) between adjacent holes so that the holes define discrete non-overlapping fields of view for their corresponding sensing channels. As the diameter becomes smaller and smaller until the diffraction-limited diameter (the diffraction-limited diameter varies with the wavelength of the incident light and the numerical aperture of the volume imaging lens), the hole defines a narrower field of view (i.e., a field of view with a smaller diameter) and delivers a sharper but lower intensity (attenuated) signal from the volume imaging optical device 130 to its corresponding lens. Therefore, the hole layer 140 can define holes having a diameter that is: greater than the diffraction-limited diameter for the wavelength of light output by the illumination source (e.g., 900 nm); substantially greater than the thickness of the hole layer 140; and less than the hole spacing distance, which is substantially equivalent to the lens spacing distance and the pixel spacing distance. In one example, the hole layer 140 can define holes with a diameter close to the diffraction-limited diameter to maximize the geometric selectivity of the field of view of each sensing channel. Alternatively, the holes may have a diameter that is less than the diffraction-limited diameter for the wavelength of light output by the illumination source. In one example, the hole layer 140 may define holes having a diameter that matches the power output of the illumination source in the system and matches the number and photon detection capabilities of the sub-pixel photodetectors in each pixel in the pixel set 170 to achieve a target number of photons incident on each pixel during each sampling period. In this example, each hole may define a specific diameter that achieves a target attenuation range for the pixel originating from the corresponding illumination source and incident on the volume imaging optical device 130 during the sampling period. In particular, because the holes in the hole layer 140 attenuate the signal that is passed to its corresponding lens and arrives at its corresponding pixel, the diameter of the hole may match the dynamic range of its corresponding pixel.

[0028] In one implementation, a first hole 141 in the hole layer 140 passes light reflected from a discrete area of ​​a surface located in front of the volume imaging optical device 130 in the field (the field of view of the sensing channel) to its corresponding lens; a stop region 146 interposed between the first hole 141 and an adjacent hole in the hole layer 140 blocks light reflected from an area of ​​the surface located outside the field of view of the first hole 141 from passing to the lens corresponding to the first hole 141. Thus, in the one-dimensional optical system 100, the hole layer 140 defines a hole column that defines a plurality of discrete non-overlapping fields of view having a substantially infinite depth of field, such as Figure 2 as shown in .

[0029] In this implementation, a first hole 141 in the hole layer 140 defines a field of view that is distinct and does not intersect with a field of view defined by another hole in the hole layer 140, such as Figure 2. The illumination source set 110 includes a first illumination source 111 that is paired with a first aperture 141 and is configured to project an illumination light beam that is substantially aligned with (i.e., overlaps) a field of view of the first aperture 141 located in front of the volume imaging optical device 130 in the field. In addition, the first illumination source 111 and the volume emission optical device 120 can cooperate to project an illumination light beam having a cross-section that is substantially similar to (and slightly larger than) a cross-section of the field of view of the first aperture 141 at various distances from the volume imaging optical device 130. Therefore, light output by the first illumination source 111 paired with the first aperture 141 and projected into the field of view of the first aperture 141 can be substantially kept outside the field of view of other apertures in the aperture layer 140.

[0030] In general, photons projected into the field by the first illumination source 111 illuminate a particular region of a surface (or surfaces) in the field that is within the field of view of the first sensing channel and are reflected (e.g., scattered) by the surface (or surfaces); at least some of these photons reflected by the particular region of the surface can reach the volume imaging optics 130, which directs these photons toward the focal plane. Because these photons are reflected by regions of the surface within the field of view of the first aperture 141, the volume imaging optics 130 can project these photons into the first aperture 141, and the first aperture 141 can pass these photons into the first lens 151 (or a subset of these photons that are incident at angles below a threshold angle relative to the axis of the first aperture 141). However, because the second aperture 142 in the aperture layer 140 is offset from the first aperture 141 and because the specific region of the surface in the field illuminated by the first illumination source 111 does not (substantially) coincide with the field of view of the second aperture 142, the photons reflected by the specific region of the surface and reaching the volume imaging optical device 130 are projected into the second aperture 142 and are passed to the second lens 152 behind the second aperture 142, and vice versa, as shown in FIG. Figure 2 In addition, the stop region 146 between the first and second apertures 142 can block photons reflected by the volume imaging optics 130 directed toward the focal plane between the first and second apertures 142, thereby reducing crosstalk between the first sensing channel and the second sensing channel.

[0031] For the first aperture 141 in the aperture layer 140 paired with the first illumination source 111 in the illumination source set 110, the first aperture 141 in the aperture layer 140 defines a first field of view and transmits light originating from a surface in the field that coincides with the first field of view or reflected from the surface to the first lens 151. Because the illumination beam projected by the first illumination source 111 substantially coincides with (and is substantially the same size as or at least larger than) the field of view defined by the first aperture 141 (e.g., Figure 4111 to the first lens 151. As shown in FIG. 11 , the signal delivered by the first aperture 141 in the aperture layer 140 to the first lens 151 may exhibit a relatively high ratio of light originating from the first illumination source 111 to light originating from other illumination sources in the system. In general, because various illumination sources in the system may output illumination beams of different frequencies, duty cycles, and / or power levels, etc., at particular times during operation, light delivered from the volume imaging optics 130 to the first pixel 171 in the pixel set 170 but originating from illumination sources other than the first illumination source 111 paired with the first pixel 171 constitutes noise at the first pixel 171. Although the relatively small diameter of the apertures in the aperture layer 140 may attenuate the total light signal delivered from the volume imaging optics 130 to the lens set 150, each aperture in the aperture layer 140 may deliver a relatively high proportion of photons originating from its corresponding illumination source compared to photons originating from other illumination sources in the system; that is, due to the geometry of the particular aperture and its corresponding illumination source, the particular aperture may deliver a signal exhibiting a relatively high SNR to its corresponding lens and, therefore, to its corresponding pixel. Furthermore, as the diameter of the holes in the hole layer 140 is smaller, and thus the field of view of the corresponding channel is smaller, the system may transfer less noise from solar radiation or other ambient light sources to the pixel set 170 .

[0032] In one variation, the system includes a second aperture layer interposed between the lens array and the filter 160, wherein the second aperture layer defines a second set of apertures 144, each aperture being aligned with a corresponding lens in the lens set 150, as described above. In this variation, as described above, the apertures in the second aperture layer 140 can absorb or reflect erroneous light passed by the corresponding lens to further reduce crosstalk between channels, thereby improving the SNR within the system. Similarly, the system can additionally or alternatively include a third aperture layer interposed between the filter 160 and the diffuser(s) 180, wherein the third aperture layer defines a third set of apertures 144, each aperture being aligned with a corresponding lens in the lens set 150, as described above. In this variation, as described above, the apertures in the third aperture layer can absorb or reflect erroneous light passed by the light filter to again reduce crosstalk between channels, thereby improving the SNR within the system.

[0033] 1.4 Lens Array

[0034] The system includes a lens set 150, wherein each lens in the lens set 150 is characterized by a second focal length, is offset from the focal plane by the second focal length relative to the volume imaging optical device 130, is aligned with a corresponding aperture in the aperture set 144, and is configured to collimate light passing through the corresponding aperture. In general, the lenses in the lens set 150 are used to collimate light passing through their corresponding apertures and pass these collimated light rays into the filter 160.

[0035] In the one-dimensional optical system 100, the lenses are arranged in a single column, and adjacent lenses are offset by a uniform lens pitch distance (ie, the center-to-center distance between adjacent pixels), such as Figure 3 . The lens set 150 is interposed between the aperture layer and the filter 160. In particular, each lens can include a converging lens characterized by a second focal length and can be offset from the focal plane of the volume imaging optical device 130 relative to the volume imaging optical device 130 by the second focal length to preserve the aperture of the volume imaging optical device 130 and collimate light incident on the volume imaging optical device 130 and passed by the corresponding aperture. Each lens in the lens set is characterized by a relatively short focal length (i.e., less than the focal length of the volume imaging optical device 130) and a relatively large marginal ray angle (e.g., a relatively high numerical aperture lens) so that the lens can capture high-angle light projected toward the lens through the range of the volume imaging optical device 130. That is, each lens in the lens set can be characterized by a ray cone that substantially matches the ray cone of the volume imaging optical device 130.

[0036] The lenses in lens set 150 can be substantially similar. The lenses in lens set 150 are configured to collimate the light focused into their corresponding apertures by volume imaging optical device 130. For example, the lenses in lens set 150 can include biconvex lenses or plano-convex lenses characterized by a focal length selected based on the size (e.g., diameter) of their corresponding apertures and the operating wavelength of the system. In this example, the focal length (f) of the lenses in lens set 150 can be calculated according to the following formula:

[0037]

[0038] Where d is the diameter of the corresponding hole in the aperture layer, and λ is the operating wavelength of light output by the illumination source (e.g., 900 nm). Thus, the geometry of the lenses in lens set 150 can be matched to the geometry of the corresponding holes in the aperture layer so that the lenses pass substantially sharp images of light at or near the operating wavelength into filter 160 and, therefore, onto the pixel array.

[0039] However, lens set 150 may include lenses having any other geometric shapes and arranged adjacent to the aperture layer in any other manner.

[0040] 1.5 Filter

[0041] like Figure 3As shown in , the system includes a filter 160, which is adjacent to the lens set 150, opposite the aperture layer and configured to pass light at the working wavelength. In general, the filter 160 receives electromagnetic radiation within the spectrum from the lens set 150, passes a relatively narrow band of electromagnetic radiation including radiation at the working wavelength to the pixel array, and blocks electromagnetic radiation outside the band. In particular, electromagnetic radiation such as ambient light other than electromagnetic radiation output by the illumination source that is incident on pixels in the pixel set 170 constitutes noise in the system. Therefore, the filter 160 is used to reject electromagnetic radiation outside the working wavelength, or more practically, to reject electromagnetic radiation outside the narrow wavelength band, thereby reducing noise in the system and increasing the SNR.

[0042] In one implementation, the optical filter 160 comprises an optical bandpass filter that passes a narrow band of electromagnetic radiation substantially centered at the operating wavelength of the system. In one example, the illumination source outputs light at an operating wavelength of (primarily) 900 nm, and the optical filter 160 is configured to pass light between 899.95 nm and 900.05 nm and block light outside of this band.

[0043] The filter 160 can selectively pass and reject wavelengths of light based on the angle of incidence on the filter 160. In general, a bandpass filter can pass wavelengths of light that are inversely proportional to the angle of incidence of the light on the bandpass filter. For example, for a filter 160 that includes a 0.5 nm wide bandpass filter, for light incident on the filter 160 at an angle of incidence of approximately 0°, the filter 160 can pass more than 95% of electromagnetic radiation over a sharp band from 899.75 nm to 900.25 nm and reject approximately 100% of electromagnetic radiation below 899.70 nm and above 900.30 nm. However, in this example, for light incident on the filter 160 at an angle of incidence of about 15°, the filter 160 can pass more than 95% of electromagnetic radiation over a narrow band from 899.5 nm to 900.00 nm and reject about 100% of electromagnetic radiation over a wider band below 899.50 nm and above 900.30 nm. Thus, the plane of incidence of the filter 160 can be substantially perpendicular to the axis of the lens, and the lens set 150 can collimate the light rays received through the corresponding apertures and output these light rays substantially perpendicular to the plane of incidence of the filter 160 (i.e., at an angle of incidence of about 0° on the filter). Specifically, the lens set 150 can output light toward the filter 160 at an angle of incidence of about 0°, so that substantially all of the electromagnetic radiation passed by the filter 160 is at or very close to the operating wavelength of the system.

[0044] In one-dimensional optical system 100, the system may include a single filter 160 that spans a column of lenses in lens set 150. Alternatively, the system may include a plurality of filters 160, each adjacent to a single lens or subset of lenses in lens set 150. However, filter 160 may define any other geometric shape and may be used in any other manner to pass only a limited band of wavelengths of light.

[0045] 1.6 Pixel Array and Diffuser

[0046] The system includes a pixel set 170 adjacent to the filter 160 and opposite to the lens set 150, each pixel in the pixel set 170 corresponding to a lens in the lens set 150 and including a set of sub-pixels arranged along a second axis that is not parallel to the first axis. In general, the pixel set 170 is offset from the filter 160 opposite to the lens set 150, and each pixel in the pixel set 170 is used to output a single signal or a signal stream corresponding to a count of photons incident on the pixel during one or more sampling periods, wherein the duration of each sampling period can be picoseconds, nanoseconds, microseconds, or milliseconds.

[0047] The system also includes a diffuser 180 interposed between the filter 160 and the pixel set 170 and configured to spread the collimated light output from each lens in the lens set 150 over a set of sub-pixels of a single corresponding pixel in the pixel set 170. In general, for each lens in the lens set 150, the diffuser 180 is used to spread the light previously collimated by the lens and passed by the filter 160 over the width and height of the sensing area within the corresponding pixel. The diffuser 180 can define a single optical element spanning the lens set 150, or the diffuser 180 can include multiple discrete optical elements, such as including one optical diffuser element aligned with each channel in the system.

[0048] In one implementation, the first pixel 171 in the pixel set 170 includes a single photon avalanche diode detector (hereinafter “SPAD”) array, and the diffuser 180 spreads the light previously passed through the corresponding first aperture 141, collimated by the corresponding first lens 151, and passed by the filter 160 over the area of ​​the first pixel 171, as shown in FIG. Figure 3 , Figure 5 and Figure 6As shown. In general, adjacent holes can be aligned and vertically offset by an hole spacing distance, adjacent lenses can be aligned and vertically offset by a lens spacing distance that is substantially equal to the hole spacing distance, and adjacent pixels can be aligned and vertically offset by a pixel spacing distance that is substantially equal to the lens spacing distance and the hole spacing distance. However, the pixel spacing distance can accommodate only a relatively small number (e.g., two) of vertically stacked SPADs. Therefore, each pixel in pixel set 170 can define an aspect ratio greater than 1:1, and diffuser 180 can spread light passed by filter 160 according to the geometry of the corresponding pixel so as to accommodate a larger sensing area for each pixel.

[0049] In one example, each pixel in the pixel set 170 is arranged on the image sensor, and the first pixel 171 in the pixel set 170 includes a single row of 16 SPADs spaced apart along a transverse axis perpendicular to the vertical axis bisecting the column of holes and lenses. In this example, the height of a single SPAD in the first pixel 171 can be less than the height (e.g., diameter) of the first lens 151, but the total length of the 16 SPADs can be greater than the width (e.g., diameter) of the first lens 151; therefore, the diffuser 180 can converge the light output from the first lens 151 to a height corresponding to the height of the SPAD at the plane of the first pixel 171, and can diverge the light output from the first lens 151 to a width corresponding to the width of the 16 SPADs at the plane of the first pixel 171. In this example, the remaining pixels in the pixel set 170 can include similar rows of SPADs, and the diffuser 180 can similarly converge and diverge the light passing through the corresponding hole to the corresponding pixel.

[0050] In the foregoing example, the hole layer may include a column of 16 similar holes, the lens set 150 may include a column of 16 similar lenses arranged behind the hole layer, and the pixel set 170 may include a set of 16 similar pixels arranged behind the lens set 150, each pixel including a similar SPAD array. For a 6.4 mm wide and 6.4 mm high image sensor, each pixel may include a single row of 16 SPADs, each of which is electrically coupled to a remote analog front-end processing electronics / digital processing electronics circuit 240. Each SPAD may be arranged in a 400 μm wide and 400 μm high SPAD area, and may define an active sensing area with a diameter of approximately 400 μm. Adjacent SPADs may be offset by a SPAD pitch distance of 400 μm. In this example, the hole pitch distance along the vertical column of holes, the lens pitch distance along the vertical column of lenses, and the pixel pitch distance along the vertical column of pixels may each be approximately 400 μm, respectively. For a first sensing channel in the system (i.e., first aperture 141, first lens 151, and first pixel 171, etc.), a first diffuser 180 may diverge a cylindrical light ray (such as a light column of approximately 100 μm diameter for an aperture layer aspect ratio of 1:4) passing through the filter 160 from the first lens 151 to a height of approximately 400 μm vertically aligned with the SPAD row in the first pixel 171. The first diffuser may similarly diverge a cylindrical light ray passing through the filter 160 from the first lens 151 to a width of approximately 6.4 μm horizontally centered within the SPAD row in the first pixel 171. Other diffusers 180 in the system may similarly diverge (or converge) collimated light passed by a corresponding lens within a corresponding pixel in the pixel set 170. Thus, in this example, by connecting each SPAD (or each pixel) to remote analog front end processing electronics / digital processing electronics circuitry 240 and by incorporating a diffuser 180 that spreads the light passed by the filter 160 over the breadth and height of the corresponding pixel, the system can achieve a relatively high sensing area fill factor within the image sensor.

[0051] Thus, in one-dimensional optical system 100, pixels in pixel set 170 may include an array of multiple SPADs arranged with an aspect ratio exceeding 1:1, and diffuser 180 may cause light to spread over corresponding non-square pixels, which enables a relatively large number of SPADs to be tiled within a single pixel to achieve a greater dynamic range within the image sensor than an image sensor having a single SPAD for each pixel, such as Figure 3As shown in . In particular, by integrating multiple SPADs for each pixel (i.e., each sensing channel), the first sensing channel in the system can detect multiple incident photons originating from the surface defined by the field of view defined by the first hole 141 in the field within the span of the dead time characteristic of the SPAD. Therefore, the first sensing channel can detect the "brighter" surface in its field of view. Additionally or alternatively, the first pixel 171 in the first sensing channel can be sampled faster than the dead time characteristic of the SPAD in the first pixel 171, because although the first subset of SPADs in the first pixel 171 may stop operating (or "die") during the first sampling period due to the collection of incident photons during the first sampling period, the other SPADs in the first pixel 171 remain operational (or "alive") and can therefore collect incident photons during subsequent sampling periods. In addition, by integrating pixels characterized by a relatively high aspect ratio of the photodetector, the image sensor can include pixels offset by relatively small pixel pitches, but the system 100 can still achieve pixels with a relatively high dynamic range.

[0052] However, the pixels in the pixel set 170 may include any other number of SPADs arranged in any other array, such as in a 64×1 grid array (as described above), in a 32×2 grid array, or in a 16×4 grid array, and the diffuser 180 may accordingly converge and / or diverge the collimated light onto the corresponding pixels in any other suitable manner. In addition, each pixel in the pixel set 170 may also include one or more linear avalanche photodiodes, Geiger mode avalanche photodiodes, photomultiplier tubes, resonant cavity photodiodes, QUANTUM DOT detectors, or other types of photodetectors arranged as described above instead of (or in addition to) SPADs, and the (one or more) diffusers 180 may similarly converge and diverge the signal passed by the (one or more) filters 160 within the corresponding pixel, as described herein.

[0053] 1.7 Illumination Source

[0054] The system includes a set of illumination sources 110 arranged along a first axis, each illumination source in the set of illumination sources 110 being configured to output an illumination beam at an operating wavelength toward a discrete point in the field located in front of the illumination source. In general, each illumination source is configured to output an illumination beam that coincides with a field of view defined by a corresponding aperture in the set of apertures 144, such as Figure 1 and Figure 2 as shown in .

[0055] In one implementation, the illumination source set 110 includes a bulk emitter optic and one discrete emitter for each sensing channel. For example, the illumination source set 110 may include a monolithic VCSEL array that includes a set of discrete emitters. In this implementation, the bulk emitter optic may be substantially identical to the bulk imaging optic 130 in terms of materials, geometry (e.g., focal length), thermal isolation, etc., and the bulk emitter optic is adjacent to and laterally and / or vertically offset from the bulk imaging optic 130. In a first example, the illumination source set 110 includes a laser array that includes discrete emitters arranged in columns, with adjacent emitters offset by an emitter spacing distance that is substantially equal to the aperture spacing distance. In this first example, each emitter outputs an illumination beam having a diameter substantially equal to or slightly larger than the diameter of a corresponding hole in the hole layer, and the array of emitters is arranged along the focal plane of the body emitter optics such that each illumination beam projected into the field from the body emitter optics intersects the field of view of the corresponding sensing channel and has substantially the same size and geometry as the field of view of the corresponding sensing channel, as shown in FIG. Figure 4 Thus, substantially all of the power output by each emitter in illumination source set 110 may be projected into the field of view of its corresponding sensing channel, with relatively minimal power wasted on surfaces in the illumination field that are outside the field of view of the sensing channel.

[0056] In a second example, discrete emitters are similarly arranged in columns with adjacent emitters offset by an emitter pitch distance that is twice the aperture pitch distance, as shown in FIG. Figure 2. In this second example, each emitter is characterized by an illumination active area (or hole) having a diameter that is approximately (or slightly greater than) twice the diameter of the corresponding hole in the aperture layer, and the emitter array is offset behind the body emitter optics by twice the focal length of the body emitter optics, such that each illumination beam projected into the field from the body emitter optics intersects the field of view of the corresponding sensing channel and has substantially the same size and geometry as the field of view of the corresponding sensing channel, as described above. In addition, for the same illumination beam power density, the illumination beam output by the emitter in this second example can contain four times the power of the illumination beam output by the emitter in the first example described above. Thus, the system can include an emitter collection that is arranged according to an emitter spacing distance, is configured to output an illumination beam of a certain diameter, and is offset behind the body emitter optics by an offset distance that varies with a scale factor (e.g., 2.0 or 3.0) and 1) the hole spacing distance in the aperture layer, 2) the diameter of the hole in the aperture layer, and 3) the focal length of the body emitter optics. Thus, a system may include an illumination subsystem that is proportionally larger than a corresponding receiver subsystem to achieve a greater total output illumination power within the same beam angle and field of view of a corresponding channel in the receiver subsystem.

[0057] The system may also include a plurality of discrete sets of illumination sources, each set of illumination sources 110 being paired with a discrete body emitter optical device adjacent to the body imaging optical device 130. For example, the system may include a first body emitter optical device, a second body emitter optical device, and a third body emitter optical device radially patterned around the body imaging optical device 130 at a uniform radial distance from the body imaging optical device 130 and spaced apart by an angular distance of 120°. In this example, the system may include a laser array with an emitter as described above behind each of the first body emitter optical device, the second body emitter optical device, and the third body emitter optical device. Thus, each discrete laser array and its corresponding body emitter optical device may project an illumination beam set into a field of view defined by a corresponding aperture in the aperture layer. Thus, in this example, three discrete laser arrays and three corresponding body emitter optical devices may collaborate to project three times the power onto the field of view of a sensing channel in the system compared to a single laser array and one body emitter optical device. Additionally or alternatively, the system may include multiple discrete laser arrays and body emitter optics to: 1) achieve a target illumination power output into the field of view of each sensing channel in the receiver subsystem with multiple lower power emitters for each sensing channel; and 2) distribute the optical energy over a larger area in the near field to achieve an optical energy density that is less than the threshold allowable optical energy density of the human eye.

[0058] However, the system may include any other number and configuration of illumination source sets and body emitter optics configured to illuminate the field of view defined by the sensing channel. The illumination source set 110 may also include any other suitable type of emitter, such as a 1×16 beam splitter powered by a single laser diode, a side-emitting laser diode array, an LED array, or a quantum dot LED array, etc.

[0059] 1.8 Manufacturing

[0060] In one implementation, the bulk receiver lens, aperture layer, lens set 150, filter 160, and diffuser 180 are fabricated and then aligned with and mounted on the image sensor. For example, the filter 160 can be fabricated by coating a fused silica substrate. Then, a photoactive optical polymer can be deposited on the filter 160, and a lens mold can be placed on the photoactive optical polymer, and a UV light source is activated to cure the photoactive optical polymer into the form of a lens patterned on the filter 160. A standoff can be similarly molded or formed on the filter 160 via photolithography, and then the aperture layer defined by the selectively cured metallized glass wafer can be bonded or otherwise mounted to the standoff to form the aperture layer. The assembly can then be reversed, and a discrete diffuser set and standoff can be similarly fabricated on the opposite side of the filter 160. Then, a discrete image sensor can be aligned with and bonded to the standoff, and the bulk imaging optical device 130 can be similarly mounted on the aperture layer.

[0061] Alternatively, photolithography and wafer-level bonding techniques can be implemented to fabricate the bulk optical imaging optics, aperture layer, lens set 150, filter 160, and diffuser 180 directly onto an uncut semiconductor wafer containing the detector chip in order to simplify manufacturing, reduce cost, and reduce the optical stack height to reduce pixel crosstalk.

[0062] 2. One-dimensional optical system: lens tube

[0063] A variation of the system includes: an illumination source set 110 arranged along a first axis, each illumination source in the illumination source set 110 being configured to output an illumination beam of an operating wavelength toward a discrete point in a field located in front of the illumination source; a volume imaging optical device 130 characterized by a focal plane relative to the field; a lens tube set 210 arranged in a linear array parallel to the first axis, each lens tube in the lens tube set 210 including a lens characterized by a focal length, offset from the focal plane, and configured to collimate light reflected into the volume imaging optical device 130 from a discrete point in the field illuminated by a corresponding illumination source in the optical device set; and a cylindrical wall 218 extending from the lens relative to the focal plane, defining a major axis substantially perpendicular to the first axis, and configured to absorb incident light reflected into the volume imaging optical device 130 from an area in the field located outside of the discrete point illuminated by the corresponding illumination source. In this variation, the system further includes: a filter 160 adjacent to the lens tube set 210, opposite to the focal plane and configured to pass light of a working wavelength; a pixel set 170 adjacent to the filter 160, opposite to the lens set 150, each pixel in the pixel set 170 corresponding to a lens in the lens set 150 and including a set of sub-pixels aligned along a third axis perpendicular to the first axis; and a diffuser 180 interposed between the filter 160 and the pixel set 170 and configured to spread the collimated light output from each lens in the lens set 150 over a set of sub-pixels of a corresponding pixel in the pixel set 170.

[0064] In general, in this variation, the system includes a lens tube that replaces (or is in addition to) each of the apertures and lens pairs described above. In this variation, each lens tube can be characterized by a second (short) focal length and can be offset from the focal plane of the volume imaging optical device 130 by the second focal length to preserve the aperture of the volume imaging optical device 130 and to collimate the incident light received from the volume imaging optical device 130, as described above and as Figure 5 and Figure 7 as shown in .

[0065] Each lens tube also defines an opaque cylindrical wall 218 that defines an axis perpendicular to the plane of incidence of the adjacent filter 160 and is configured to absorb incident light, such as Figure 5. In general, as the axial length increases, the cylindrical wall 218 of the lens tube can absorb light passing through the lens tube at a shallower angle to the axis of the lens tube, thereby reducing the field of view of the lens tube (which can be similar to reducing the diameter of the holes in the aperture layer until the diffraction-limited diameter, as described above) and producing an output signal that is closer to collimated light perpendicular to the incident plane of the filter 160. Therefore, each lens tube can define an elongated cylindrical wall 218 having a length sufficient to achieve a target field of view and pass collimated light at a maximum angle less than a threshold angle to the axis of the lens tube. In this variation, the lens tube can therefore be used as an aperture sensing pair as described above to define a narrow field of view and output substantially collimated light to an adjacent filter 160.

[0066] The cylindrical wall 218 of the lens tube may define a roughened or patterned opaque interface surrounding a transparent (or translucent) lens material, such as Figure 5 , to increase the absorption and reduce the reflection of light incident on the cylindrical wall 218. Each lens tube (and each lens described above) may also be coated with an anti-reflective coating.

[0067] like Fig. 9 As shown in , in this variation, the lens tube collection 210 can be manufactured by implementing photolithography techniques to pattern a light-active optical polymer (e.g., SU8) onto the filter 160 (e.g., on a silicon wafer defining the filter). The light-absorbing polymer can then be poured between the lens tubes and cured. The lens collection 150 can then be separately manufactured (e.g., molded) and then bonded to the lens tube. Alternatively, the lenses can be manufactured directly on the lens tubes by photolithography techniques. Alternatively, the mold for the lens can be cast directly onto the lens tube by injecting the polymer into a mold arranged on the lens tube. A single diffuser 180 or multiple discrete diffusers 180 can be similarly manufactured and / or assembled on the filter 160 opposite the lens tube. A bracket extending from the filter 160 can be similarly manufactured or mounted around (one or more) diffusers 180, and the image sensor can be aligned with the bracket and bonded to the filter 160 opposite the filter 160. Other optical elements within the system (eg, volume imaging lenses, volume emission lenses, etc.) may be fabricated according to similar techniques and using similar materials.

[0068] 3. Two-dimensional optical system

[0069] Another variation of the system includes: a set of illumination sources 110 arranged in a first rectilinear grid array, each illumination source in the set of illumination sources 110 being configured to output an illumination beam at an operating wavelength toward a discrete point in a field located in front of the illumination source; a volume imaging optical device 130 characterized by a focal plane relative to the field; an aperture layer coincident with the focal plane, a set of apertures 144 defined in a second rectilinear grid array proportional to the first rectilinear grid array, and a stop region 146 defined around the set of apertures 144, each aperture in the set of apertures 144 defining a field of view in the field coincident with a discrete point output by a corresponding illumination source in the set of illumination sources 110, the stop region 146 absorbing reflections from surfaces in the field located outside the field of view defined by the set of apertures 144 and passing through the volume imaging optical device 130 light; a lens set 150, each lens in the lens set 150 being characterized by a second focal length, being offset from the focal plane by the second focal length relative to the volume imaging optical device 130, being aligned with an aperture in the aperture set 144 and being configured to collimate light passing through the aperture; a filter 160, being adjacent to the lens set 150, being opposite to the aperture layer and being configured to pass light of a working wavelength; a pixel set 170, being adjacent to the filter 160, being opposite to the lens set 150, each pixel in the pixel set 170 being aligned with a subset of lenses in the lens set 150; and a diffuser 180, being interposed between the filter 160 and the pixel set 170 and being configured to spread the collimated light output from each lens in the lens set 150 over corresponding pixels in the pixel set 170.

[0070] In general, in this variation, the system includes a two-dimensional grid array of channels (i.e., apertures, lenses, and pixel sets or lens tubes and pixel sets) and is configured to image a volume occupied by the system in two dimensions. The system can collect one-dimensional distance data within the two-dimensional field, such as counts of incident photons within a sampling period and / or times between consecutive photons incident on pixels at known positions in the field corresponding to a known field of view. The one-dimensional distance data can then be combined with the known positions of the field of view of each channel in the system to reconstruct a virtual three-dimensional representation of the field located in front of the system.

[0071] In this variation, the aperture layer may define a grid array of apertures, the lens set 150 may be arranged in a similar grid array with one lens aligned with one aperture in the aperture layer, and the pixel set 170 may include one pixel for each aperture and lens pair, as described above. For example, the aperture layer may define a 24×24 grid array of 200 μm diameter apertures, with the apertures offset vertically and laterally by an aperture pitch distance of 300 μm, and the lens set 150 may similarly define a 24×24 grid array of lenses, with the lenses offset vertically and laterally by a lens pitch distance of 300 μm. In this example, the pixel set 170 may include a 24×24 grid array of 300 μm square pixels, where each pixel includes a 3×3 square array of nine 100 μm square SPADs.

[0072] Alternatively, in this variation, pixel set 170 may include one pixel for each set of multiple aperture and lens pairs. In the foregoing example, pixel set 170 may alternatively include a 12×12 grid array of 600 μm square pixels, wherein each pixel includes a 6×6 square array of 36 100 μm square SPADs, and wherein each pixel is aligned with a set of four adjacent lenses in a square grid. In this example, for each group of four adjacent lenses, the diffuser 180: can bias the collimated light output from the lens in the (1,1) position in the square grid upward and rightward so that the light passing through the (1,1) lens is spread over the entire width and width of the corresponding pixel; can bias the collimated light output from the lens in the (2,1) position in the square grid upward and leftward so that the light passing through the (2,1) lens is spread over the entire width and width of the corresponding pixel; can bias the collimated light output from the lens in the (1,2) position in the square grid downward and rightward so that the light passing through the (1,2) lens is spread over the entire width and width of the corresponding pixel; and can bias the collimated light output from the lens in the (2,2) position in the square grid downward and leftward so that the light passing through the (2,2) lens is spread over the entire width and width of the corresponding pixel, as shown in FIG. Figure 8 as shown in .

[0073] In the foregoing example, for each set of four illumination sources in a square grid and corresponding to a set of four lenses in a square grid, the system can actuate one illumination source in the set of four illumination sources at any given moment. In particular, for each set of four illumination sources in a square grid corresponding to a pixel in the pixel set 170, the system can actuate the first illumination source 111 in the (1,1) position during a first sampling period to illuminate the field of view defined by the first aperture 141 corresponding to the lens in the (1,1) position in the corresponding set of four lenses, and the system can sample all 36 SPADs in the corresponding pixel during the first sampling period. Then, the system can turn off the first illumination source 111 and actuate the second illumination source 112 in the (1,2) position during a subsequent second sampling period to illuminate the field of view defined by the second aperture 142 corresponding to the lens in the (1,2) position in the corresponding set of four lenses, and the system can sample all 36 SPADs in the corresponding pixel during the second sampling period. Subsequently, the system can then turn off the first and second illumination sources 112 and actuate the third illumination source in the (2,1) position during a subsequent third sampling period to illuminate the field of view defined by the third aperture corresponding to the lens in the (2,1) position in the corresponding set of four lenses, and the system can sample all 36 SPADs in the corresponding pixel during the third sampling period. Finally, the system can turn off the first, second, and third illumination sources and actuate the fourth illumination source in the (2,2) position during a fourth sampling period to illuminate the field of view defined by the fourth aperture corresponding to the lens in the (2,2) position in the corresponding set of four lenses, and the system can sample all 36 SPADs in the corresponding pixel during the fourth sampling period. The system can repeat this process throughout its operation.

[0074] Thus, in the aforementioned example, the system may include a set of pixels 170 arranged within an image sensor having a width of 7.2 mm and a length of 7.2 mm, and may implement a scanning mode such that each channel in the system has access to multiple SPADs (light may be projected onto multiple SPADs), which would otherwise require a much larger image sensor (e.g., a 14.4 mm×14.4 mm image sensor). In particular, the system may implement a serial scanning mode for each set of illumination sources to achieve an exponential increase in the dynamic range of each channel in the system. In particular, in this variation, the system may implement the aforementioned imaging techniques to increase the imaging resolution of the system.

[0075] In the aforementioned implementation, the system may further include a shutter 182 between each channel and the image sensor, and the system may selectively open and close each shutter 182 when the illumination source of the corresponding channel is respectively actuated and deactivated. For example, the system may include an independently operable electrochromic shutter 182 inserted between each lens, and when the (1,1) illumination source is activated, the system may open the electrochromic shutter 182 above the (1,1) lens in the square grid group of four lenses and close the electrochromic shutters 182 above the (1,2), (2,1) and (2,2) lenses, thereby rejecting noise passing through the (1,2), (2,1) and (2,2) lenses to reach the corresponding pixels on the image sensor. Therefore, the system may selectively open and close the shutter 182 between each channel and the image sensor to increase the SNR of each channel during operation. Alternatively, the system may include an independently operable electrochromic shutter 182 arranged above a selected area of ​​each pixel, such as Figure 8 , where each electrochromic shutter 182 is aligned with a single channel (ie, with a single lens in the lens set). The system may alternatively include a MEMS mechanical shutter or any other suitable type of shutter interposed between the lens set 150 and the image sensor.

[0076] In this variation, the system may define a two-dimensional grid array of apertures, lenses, diffusers, and / or pixels characterized by a first pitch distance along a first (e.g., X) axis and a second pitch distance different from the first pitch distance along a second (e.g., Y) axis. For example, the image sensor may include pixels offset by a 25 μm horizontal pitch and a 300 μm vertical pitch, wherein each pixel includes a single row of 12 sub-pixels.

[0077] However, in this variation, the two-dimensional optical system may include any other number and pattern of channels (e.g., apertures, lenses (or lens tubes), and diffusers) and arrays of pixels, and may perform any other suitable scanning pattern to achieve a spatial resolution for each channel that is higher than the native pixel resolution of the image sensor. The system may additionally or alternatively include converging optics, diverging optics, and / or any other suitable type of optical element to spread light passing through a channel over the width of a corresponding pixel.

[0078] As those skilled in the art will recognize from the foregoing detailed description and from the accompanying drawings and claims, modifications and changes may be made to the embodiments of the present invention without departing from the scope of the invention as defined by the following claims.

Claims

1. An optical system for collecting distance information, the optical system comprising: Volume emission optics; an emitter array, the emitter array comprising a plurality of emitters having an operating wavelength, each emitter of the plurality of emitters being configured to output an illumination beam of the operating wavelength through the body emission optics toward a point in a field external to the optical system, the illumination beam not overlapping with illumination beams from other emitters of the plurality of emitters; Volume imaging optics; a detector array comprising a plurality of pixels disposed behind the volume imaging optics, each pixel of the plurality of pixels comprising a plurality of single photon avalanche diodes (SPADs) operable to detect photons emitted from the emitter array and received by the volume imaging optics after being reflected from a surface within the field, wherein each SPAD is electrically coupled to digital processing electronics circuitry; as well as a plurality of optical elements disposed between the detector array and the volume imaging optics, the plurality of optical elements comprising an aperture layer and a filter layer, the aperture layer comprising a plurality of apertures separated by stop regions, the filter layer configured to pass radiation comprising the band of operating wavelengths of the plurality of emitters to the detector array while blocking radiation outside of the band of radiation; Wherein, the plurality of pixels include a first pixel, a second pixel, a third pixel and a fourth pixel; and Wherein, the multiple holes include a first hole, a second hole, a third hole and a fourth hole, the first hole is arranged in a first optical path extending from the body imaging optical device to the first pixel, the second hole is arranged in a second optical path extending from the body imaging optical device to the second pixel, the third hole is arranged in a third optical path extending from the body imaging optical device to the third pixel, and the fourth hole is arranged in a fourth optical path extending from the body imaging optical device to the fourth pixel.

2. The optical system according to claim 1, wherein: The aperture layer includes a thin opaque structure spaced apart from the volume imaging optics.

3. The optical system according to claim 1, wherein: Each pixel in the detector array is paired with an emitter in the emitter array such that the field of view of the pixel coincides with the field of view of the emitter with which the pixel is paired, and wherein each pixel in the detector array has a field of view that does not overlap with the field of view of all other pixels in the detector array.

4. The optical system according to claim 1, wherein: The emitter array is configured to project illumination beams into a field in front of the optical system according to an illumination pattern, wherein each beam in the illumination pattern is aligned with a field of view of a pixel in the detector array.

5. The optical system according to claim 1, wherein: Each pixel in the detector array is used to output a signal or a signal stream corresponding to the count of photons incident on the pixel in a sampling period.

6. The optical system according to claim 1, wherein: The volume emission optics and the volume imaging optics are each image space telecentric lenses.

7. An optical system for collecting distance information, the optical system comprising: Volume emission optics; a plurality of emitters configured to output electromagnetic radiation at an operating wavelength into a field in front of the optical system; a volume imaging optic adjacent to and laterally offset from the volume emission optic, the volume imaging optic having a focal plane opposite the field and configured to project incident light rays from outside the optical system toward the focal plane; a plurality of pixels disposed behind the volume imaging optics, the plurality of pixels operable to detect photons emitted from the plurality of emitters and received by the volume imaging optics after being reflected from a surface within the field, wherein each pixel of the plurality of pixels has a field of view that does not overlap with a field of view of all other pixels of the plurality of pixels, wherein the plurality of pixels includes at least a first pixel and a second pixel, and wherein each pixel of the plurality of pixels is electrically coupled to digital processing electronics circuitry; An aperture layer is arranged between the volume imaging optical device and the plurality of pixels, the aperture layer comprising a plurality of apertures separated from each other by a stop area, the plurality of apertures comprising a first aperture and a second aperture, the first aperture being arranged in a first optical path extending between the volume imaging optical device and the first pixel, the second aperture being arranged in a second optical path extending between the volume imaging optical device and the second pixel.

8. The optical system according to claim 7, wherein: The plurality of emitters are arranged in a first arrangement and the plurality of pixels are arranged in a second arrangement, the second arrangement being proportional to the first arrangement.

9. The optical system according to claim 7, wherein: Each pixel of the plurality of pixels includes a plurality of SPADs distributed across a sensing area of ​​the pixel.

10. The optical system according to claim 9, wherein: Each pixel is used to output a signal stream corresponding to the count of photons incident on the pixel in one sampling period.

11. The optical system according to claim 9, wherein: Each pixel is used to output a signal corresponding to the count of photons incident on the pixel during one sampling period.

12. The optical system according to claim 7, wherein: The plurality of emitters are configured to project illumination beams into the field in front of the optical system according to an illumination pattern, wherein each beam in the illumination pattern is aligned with a field of view of a pixel in the plurality of pixels.

13. The optical system according to claim 7, wherein: Each pixel includes a plurality of Geiger mode avalanche diodes.

14. The optical system according to claim 13, wherein: The plurality of pixels further include a third pixel and a fourth pixel, and the plurality of holes further include a third hole and a fourth hole, the third hole being disposed in a third optical path extending between the volume imaging optical device and the third pixel, and the fourth hole being disposed in a fourth optical path extending between the volume imaging optical device and the fourth pixel.

15. An optical system for collecting distance information, the optical system comprising: Volume emission optics; a plurality of emitters spaced apart from one another and aligned parallel to a first axis, wherein each emitter in the plurality of emitters is configured to output electromagnetic radiation at an operating wavelength toward a point in a field in front of the optical system, and the plurality of emitters includes at least a first emitter, a second emitter, a third emitter, and a fourth emitter; a volume imaging optic adjacent to and laterally offset from the volume emission optic, the volume imaging optic having a focal plane opposite the field and configured to project incident light rays from outside the optical system toward the focal plane; a plurality of pixels disposed behind the volume imaging optics, the plurality of pixels being spaced apart from one another and aligned parallel to a first axis, wherein each pixel of the plurality of pixels is electrically coupled to digital processing electronics circuitry and comprises a plurality of single photon avalanche diodes (SPADs), and wherein the plurality of pixels comprises at least a first pixel, a second pixel, a third pixel, and a fourth pixel each having a different non-overlapping field of view beyond a threshold distance; one or more optical filters disposed between the volume imaging optics and the plurality of pixels and configured to allow light of a set of wavelengths including the operating wavelength to pass through the one or more optical filters while blocking light outside of the set of wavelengths of light from reaching the plurality of pixels; a plurality of holes, the plurality of holes comprising a first hole, a second hole, a third hole, and a fourth hole separated from each other by a stop region; wherein the first pixel is operable to detect photons emitted from the first emitter and received by the volume imaging optical device and passed through the first hole after being reflected from a surface within the field, the second pixel is operable to detect photons emitted from the second emitter and received by the volume imaging optical device and passed through the second hole after being reflected from a surface within the field, the third pixel is operable to detect photons emitted from the third emitter and received by the volume imaging optical device and passed through the third hole after being reflected from a surface within the field, and the fourth pixel is operable to detect photons emitted from the fourth emitter and received by the volume imaging optical device and passed through the fourth hole after being reflected from a surface within the field.

16. The optical system according to claim 15, wherein: The one or more optical filters include an optical filter comprising a coating formed over a quartz substrate.

17. The optical system according to claim 15, wherein: The optical system is configured to collect distance data based on recorded times between emission of illumination beams emitted from the plurality of emitters and detection of photons originating from the illumination beams.

18. An optical system according to any one of the preceding claims, wherein: The plurality of emitters includes a plurality of vertical cavity surface emitting lasers (VCSELs).

19. The optical system of claim 18, further comprising a rotation mechanism configured to rotate the optical system around a rotation axis.

20. The optical system of claim 19, wherein: The optical system is configured to function as an image sensor that, when rotated about an axis parallel to the columns of apertures, collects three-dimensional distance data that can be reconstructed into a virtual three-dimensional representation of a volume occupied by the optical system.

Images