# US 10,502,830 B2 · Limitation of noise on light detectors using an aperture > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,502,830 B2 - Document ID: US10502830B2 - Status: Granted - Kind: B2 - Application number: 15/292,251 - Filed: 2016-10-13 - Published: 2018-04-19 - Granted: 2019-12-10 - Earliest claimed: 2016-10-13 - Assignees: Waymo LLC - Applicants: Google Inc. - Inventors: Pierre-Yves Droz; Blaise Gassend; Caner Onal; David Hutchison - Web page: https://patentgrep.com/patent/US10502830B2 ## CPC - G01S 17/08: for measuring distance only (indirect measurement G01S17/46; active triangulation systems G01S17/48) - G01J 1/0411: {using focussing or collimating elements, i.e. lenses or mirrors; Aberration correction} - G01J 1/0414: {using plane or convex mirrors, parallel phase plates, or plane beam-splitters} - G01J 1/0422: {using light concentrators, collectors or condensers} - G01J 1/0437: {using masks, aperture plates, spatial light modulators, spatial filters, e.g. reflective filters} - G01J 1/0448: {Adjustable, e.g. focussing} - G01J 1/0474: {Diffusers (cavities G01J2001/0481)} - G01J 1/0488: {with spectral filtering} - G01J 1/4228: {arrangements with two or more detectors, e.g. for sensitivity compensation} - G01J 1/44: Electric circuits {(for command of an exposure part G03B7/02)} - G01J 3/0208: {using focussing or collimating elements, e.g. lenses or mirrors; performing aberration correction} - G01J 3/0229: {using masks, aperture plates, spatial light modulators or spatial filters, e.g. reflective filters} - G01S 7/481: Constructional features, e.g. arrangements of optical elements - G01S 7/4816: {of receivers alone} - G01S 7/4863: Detector arrays, e.g. charge-transfer gates - G01S 7/4868: {Controlling received signal intensity or exposure of sensor} - G01S 17/10: using transmission of interrupted, pulse-modulated waves (determination of distance by phase measurements G01S17/32) - G01S 17/42: Simultaneous measurement of distance and other co-ordinates (indirect measurement G01S17/46) - G01J 2001/442: {Single-photon detection or photon counting} - G01J 2001/4466: {Avalanche} - G01S: RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES - G01J: MEASUREMENT OF INTENSITY, VELOCITY, SPECTRAL CONTENT, POLARISATION, PHASE OR PULSE CHARACTERISTICS OF INFRARED, VISIBLE OR ULTRAVIOLET LIGHT; COLORIMETRY; RADIATION PYROMETRY (light sources F21, H01J, H01K, H05B; investigating properties of materials by optical means G01N) ## Abstract The present disclosure relates to limitation of noise on light detectors using an aperture. One example embodiment includes a system. The system includes a lens disposed relative to a scene and configured to focus light from the scene onto a focal plane. The system also includes an aperture defined within an opaque material disposed at the focal plane of the lens. The aperture has a cross-sectional area. In addition, the system includes an array of light detectors disposed on a side of the focal plane opposite the lens and configured to intercept and detect diverging light focused by the lens and transmitted through the aperture. A cross-sectional area of the array of light detectors that intercepts the diverging light is greater than the cross-sectional area of the aperture. ## Claims ### Claim 1 A system, comprising: a lens disposed relative to a scene and configured to focus light from the scene onto a focal plane; an aperture defined within an opaque material disposed at the focal plane of the lens, wherein the aperture has a cross-sectional area; and an array of light detectors disposed on a side of the focal plane opposite the lens and configured to intercept and detect diverging light focused by the lens and transmitted through the aperture to the array of light detectors without reflections, wherein the array of light detectors comprises a plurality of single photon avalanche diodes (SPADs), and wherein a cross-sectional area of the array of light detectors that intercepts the diverging light is greater than the cross-sectional area of the aperture. ### Claim 2 (depends on 1) The system of claim 1, wherein the light detectors in the array are connected in parallel with one another. ### Claim 3 (depends on 1) The system of claim 1, wherein the cross-sectional area of the aperture is adjustable. ### Claim 4 (depends on 3) The system of claim 3, wherein the opaque material comprises an iris configured to define the cross-sectional area of the aperture. ### Claim 5 (depends on 3) The system of claim 3, wherein the opaque material comprises a patterned conductive electrode array having two polarizers; one or more alignment layers disposed between the two polarizers; and a liquid crystal layer disposed between the two polarizers. ### Claim 6 (depends on 1) The system of claim 1, wherein the light from the scene is light scattered by one or more objects being illuminated by a transmitter of a light detection and ranging (LIDAR) system. ### Claim 7 (depends on 1) The system of claim 1, further comprising a mirror configured to reflect the light from the scene transmitted through the aperture toward the array of light detectors. ### Claim 8 (depends on 1) The system of claim 1, wherein the light detectors are sensitive to light within a range of wavelengths. ### Claim 9 (depends on 1) The system of claim 1, wherein the light detectors are sensitive to light having infrared wavelengths. ### Claim 10 (depends on 1) The system of claim 1, further comprising a filter configured to divert light from the scene within one or more wavelength ranges away from the aperture so the light from the scene within the one or more wavelength ranges does not pass through the aperture. ### Claim 11 (depends on 1) The system of claim 1, wherein the opaque material comprises an opaque mask overlaying a glass substrate. ### Claim 12 (depends on 1) The system of claim 1, wherein the opaque material comprises a metal, and wherein the metal is etched to define the aperture. ### Claim 13 (depends on 1) The system of claim 1, wherein each light detector occupies a cross-sectional area of between 200 μm2 and 600 μm2. ### Claim 14 (depends on 1) The system of claim 1, further comprising a diffuser disposed between the array of light detectors and the aperture, wherein the diffuser is configured to diffuse the light from the scene transmitted through the aperture evenly across the array of light detectors. ### Claim 15 (depends on 1) The system of claim 1, wherein the aperture is selectable from a set of two or more apertures. ### Claim 16 (depends on 15) The system of claim 15, further comprising one or more microelectromechanical systems (MEMS) mirrors adjustable to direct the light from the scene toward the aperture to select from the set of two or more apertures. ### Claim 17 (depends on 1) The system of claim 1, wherein the aperture has a non-circular shape. ### Claim 18 (depends on 1) The system of claim 1, further comprising a structure, disposed in between the aperture and the array of light detectors, which totally internally reflects the diverging light transmitted through the aperture. ### Claim 19 (depends on 1) The system of claim 1, wherein a location of the aperture in the focal plane is adjustable. ### Claim 20 (depends on 1) The system of claim 1, wherein the aperture comprises an array of selectively switchable MEMS mirrors. ### Claim 21 A method, comprising: focusing, by a lens disposed relative to a scene, light from the scene onto a focal plane; transmitting, through an aperture defined within an opaque material disposed at the focal plane of the lens, the light from the scene, wherein the aperture has a cross-sectional area, wherein the light from the scene is transmitted to an array of light detectors disposed on a side of the focal plane opposite the lens, and wherein the light from the scene is transmitted to the array of light detectors without reflections; diverging, by the light from the scene transmitted through the aperture; intercepting, by the array of light detectors, the diverged light from the scene, wherein the array of light detectors comprises a plurality of single photon avalanche diodes (SPADs), and wherein a cross-sectional area of the array of light detectors that intercept the diverged light from the scene is greater than the cross-sectional area of the aperture; and detecting, by the array of light detectors, the intercepted light. ### Claim 22 A light detection and ranging (LIDAR) device, comprising: a LIDAR transmitter configured to illuminate a scene with light; and a LIDAR receiver configured to receive light scattered by one or more objects within the scene to map the scene, wherein the LIDAR receiver comprises: a lens configured to focus the light scattered by the one or more objects within the scene onto a focal plane; an aperture defined within an opaque material disposed at the focal plane, wherein the aperture has a cross-sectional area; and an array of light detectors disposed on a side of the focal plane opposite the lens and configured to intercept and detect diverging light focused by the lens and transmitted through the aperture to the array of light detectors without reflections, wherein the array of light detectors comprises a plurality of single photon avalanche diodes (SPADs), and wherein a cross-sectional area of the array of light detectors that intercepts the diverging light is greater than the cross-sectional area of the aperture.