Wafer level optics for folded optic passive depth sensing system

Patent metadata

Field	Value
Publication number	US-9967547-B2
Application number	US-201715484609-A
Country	US
Kind code	B2
Filing date	Apr 11, 2017
Priority date	Jun 8, 2016
Publication date	May 8, 2018
Grant date	May 8, 2018

Abstract

Certain aspects relate to wafer level optical designs for a folded optic stereoscopic imaging system. One example folded optical path includes first and second reflective surfaces defining first, second, and third optical axes, and where the first reflective surface redirects light from the first optical axis to the second optical axis and where the second reflective surface redirects light from the second optical axis to the third optical axis. Such an example folded optical path further includes wafer-level optical stacks providing ten lens surfaces distributed along the first and second optical axes. A variation on the example folded optical path includes a prism having the first reflective surface, wherein plastic lenses are formed in or secured to the input and output surfaces of the prism in place of two of the wafer-level optical stacks.

First claim

What is claimed is:

1. An imaging device comprising:
a first set of optics arranged to propagate light received from a scene along a first path, and a second set of optics arranged to propagate light received from the scene along a second path, each of the first and second sets of optics comprising
a first light folding surface positioned to redirect light propagating from a scene along a first optical axis to a second optical axis,
a first lens group positioned at least along the first optical axis, the first lens group having inverted telescopic optical properties,
a stop positioned along the second optical axis, the stop comprising an aperture, the stop positioned to receive light propagating from the first lens group such that at least a portion of the received light passes through the aperture;
at least one wafer-level optical stack positioned along the second optical axis to receive the portion of the light passed through the stop aperture, and
a second light folding surface positioned to receive light from the at least one wafer-level optical stack and redirect light along a third optical axis; and

at least one image sensor having a first portion positioned to receive light propagating along the third optical axis of the first path and having a second portion positioned to receive light propagating along the third optical axis of the second path.

2. The imaging device of claim 1 , further comprising a processor configured to:
generate a first image from signals received from the first portion of the at least one image sensor;
generate a second image from signals received from the second portion of the at least one image sensor; and
generate a depth map based on at least the first image and the second image.

3. The imaging device of claim 2 , wherein the first wafer-level optical stack and the at least one wafer-level optical stack collectively provide one or both of optical corrections for increasing a sharpness of the first and second images and chromatic aberration corrections for expanding a range of wavelengths focusable by the imaging device.

4. The imaging device of claim 1 , wherein the first optical axis of the first set of optics is separated from the first optical axis of the second set of optics by a distance of 2-5 cm.

5. The imaging device of claim 1 , wherein the first light folding surface comprises a reflective mirror.

6. The imaging device of claim 1 , further comprising a prism having an input surface positioned along the first axis to receive the light propagating from the scene and pass the light to the first light folding surface, another surface of the prism comprising the first light folding surface, and an output surface positioned along the second optical axis to pass light reflected from the first light folding surface out of the prism.

7. The imaging device of claim 6 , further comprising a first wafer-level optical stack positioned along the second optical axis to receive the light from the first lens group, wherein the aperture of the stop receives light propagating from the first wafer-level optical stack, and wherein, for each of the first and second sets of optics, the prism, the first lens group, the first wafer-level optical stack, the stop, the at least one wafer-level optical stack positioned to receive the portion of the light passed through the stop aperture, and the second light folding surface are fixed relative to one another along the first and second optical axes.

8. The imaging device of claim 7 , wherein, for each of the first and second paths, the second light folding surface is fixed relative to the at least one image sensor along the third optical axis.

9. The imaging device of claim 5 , wherein the first lens group comprises:
a plastic first lens comprising a first lens surface, the first lens formed in or secured to the input surface; and
a plastic second lens comprising a second lens surface, the second lens formed in or secured to the output surface.

10. The imaging device of claim 9 , wherein the first wafer-level optical stack comprises:
a first optical wafer;
a first wafer lens having a third lens surface, the first wafer lens secured to a first side of the first optical wafer; and
a second wafer lens having a fourth lens surface, the second wafer lens secured to a second side of the first optical wafer.

11. The imaging device of claim 10 , wherein the at least one wafer-level optical stack positioned to receive the portion of the light passed through the stop aperture comprises a second wafer-level optical stack positioned along the second optical axis to receive the light passing through the stop aperture, the second wafer-level optical stack comprising:
a second optical wafer,
a third wafer lens having a fifth lens surface, the third wafer lens secured to a first side of the second optical wafer; and
a fourth wafer lens having a fourth lens surface, the second wafer lens secured to a second side of the second optical wafer.

12. The imaging device of claim 11 , wherein the at least one wafer-level optical stack positioned to receive the portion of the light passed through the stop aperture comprises:
a third wafer-level optical stack positioned along the second optical axis to receive the light from the second wafer-level optical stack, the third wafer-level optical stack comprising
a third optical wafer,
a fifth wafer lens having a seventh lens surface, the fifth wafer lens secured to a first side of the third optical wafer, and
a sixth wafer lens having an eighth lens surface, the sixth wafer lens secured to a second side of the third optical wafer; and

a fourth wafer-level optical stack positioned along the second optical axis to receive the light from the third wafer-level optical stack, the fourth wafer-level optical stack comprising
a fourth optical wafer,
a seventh wafer lens having a ninth lens surface, the seventh wafer lens secured to a first side of the fourth optical wafer, and
an eighth wafer lens having a tenth lens surface, the eighth wafer lens secured to a second side of the fourth optical wafer.

13. The imaging device of claim 1 , wherein the at least one image sensor comprises:
a backside illuminated sensor wafer having an array of photosensitive elements and row scanning circuitry;
a processing wafer having column readout circuitry, timing control circuitry, and a reconfigurable instruction cell array image signal processor; and
at least one silicon via connecting the sensor wafer and the processing wafer.

14. The imaging device of claim 1 , wherein the inverted telescopic optical properties of the first lens group of the first set of optics increase a field of view of the first portion of the at least one image sensor and the inverted telescopic optical properties of the first lens group of the second set of optics increase a field of view of the second portion of the at least one image sensor.

15. The imaging device of claim 1 , wherein the at least one image sensor comprises a single sensor wafer having both the first portion and the second portion, wherein the first portion and the second portion do not overlap, and wherein the light propagating along the third optical axis of the first set of optics and the light propagating along the third optical axis of the second set of optics are simultaneously incident upon the sensor wafer.

16. The imaging device of claim 15 , further comprising at least one additional set of optics arranged to propagate light from the scene along at least one additional path, the single sensor comprising at least one additional portion positioned

Assignees

• Qualcomm Inc

Inventors

• Georgiev Todor Georgiev
• Li Zheng-Wu
• Sun wen-yu

Classifications

• H04N23/55 Primary

  Optical parts specially adapted for electronic image sensors; Mounting thereof · CPC title

• H04N13/218 Primary

  using spatial multiplexing · CPC title

• G02B13/0065

  having a beam-folding prism or mirror · CPC title

• H04N13/271

  wherein the generated image signals comprise depth maps or disparity maps · CPC title

• G02B27/0025

  for optical correction, e.g. distorsion, aberration · CPC title