Folded optic passive depth sensing system

Patent metadata

Field	Value
Publication number	US-9986223-B2
Application number	US-201715484637-A
Country	US
Kind code	B2
Filing date	Apr 11, 2017
Priority date	Jun 8, 2016
Publication date	May 29, 2018
Grant date	May 29, 2018

Abstract

Certain aspects relate to systems and techniques for folded optic stereoscopic imaging, wherein a number of folded optic paths each direct a different one of a corresponding number of stereoscopic images toward a portion of a single image sensor. Each folded optic path can include a set of optics including a first light folding surface positioned to receive light propagating from a scene along a first optical axis and redirect the light along a second optical axis, a second light folding surface positioned to redirect the light from the second optical axis to a third optical axis, and lens elements positioned along at least the first and second optical axes and including a first subset having telescopic optical characteristics and a second subset lengthening the optical path length. The sensor can be a three-dimensionally stacked backside illuminated sensor wafer and reconfigurable instruction cell array processing wafer that performs depth processing.

First claim

What is claimed is:

1. A stereoscopic imaging system comprising:
a first set of optics arranged to propagate light along a first path, and a second set of optics arranged to propagate light along a second path, each of the first and second paths having a first optical axis, a second optical axis, and a third optical axis, each of the first and second sets of optics comprising
a first light folding surface positioned to receive light propagating from a scene along the first optical axis and redirect the light along the second optical axis,
a second light folding surface positioned to receive the light propagating along the second optical axis and redirect the light along the third optical axis, and
a plurality of lens elements positioned along at least the first and second optical axis, the plurality of lens elements including a first subset having inverted telescopic optical characteristics and a second subset lengthening a length of the first or second path; and

an image sensor having a first region positioned to receive light propagating along the third optical axis of the first set of optics and having a second region positioned to receive light propagating along the third optical axis of the second set of optics.

2. The stereoscopic imaging system of claim 1 , 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 image sensor.

3. The stereoscopic imaging system of claim 1 , wherein the first region of the image sensor does not overlap with the second region of the image sensor.

4. The stereoscopic imaging system 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 stereoscopic imaging system of claim 1 , further comprising a processor configured to generate a first stereoscopic image from signals received from the first region of the image sensor and a second stereoscopic image from signals received from the second region of the image sensor.

6. The stereoscopic imaging system of claim 5 , wherein the processor is further configured to generate depth information based on the first and second stereoscopic images.

7. The stereoscopic imaging system of claim 5 , wherein the image sensor comprises a first wafer having an array of photosensitive elements and row scanning circuitry, and wherein the processor comprises a second wafer having column readout circuitry, timing control circuitry, and a reconfigurable instruction cell array image signal processor.

8. The stereoscopic imaging system of claim 5 , further comprising at least one silicon via connecting the first wafer with the second wafer.

9. The stereoscopic imaging system of claim 6 , wherein the first wafer comprises a backside illuminated CMOS wafer.

10. The stereoscopic imaging system of claim 1 , wherein the image sensor comprises a plurality of photosensitive elements, a first subset of the plurality of photosensitive elements positioned in the first region and a second subset of the plurality of photosensitive elements positioned in the second region.

11. The stereoscopic imaging system of claim 8 , further comprising a plurality of microlenses each positioned over a corresponding one of the plurality of photosensitive elements, a first subset of the plurality of microlenses positioned over the first subset of the plurality of photosensitive elements in the first region of the image sensor and a second subset of the plurality of microlenses positioned over the second plurality of photosensitive elements in the second region of the image sensor.

12. The stereoscopic imaging system of claim 9 , wherein:
a center of each of the plurality of microlenses is shifted by a predetermined shift amount relative to a center of the corresponding one of the plurality of photosensitive elements;
the predetermined shift amount of the first subset of the plurality of microlenses is determined based on a radial distance from a center of the first subset of the plurality of photosensitive elements; and
the predetermined shift amount of the second subset of the plurality of microlenses determined is based on a radial distance from a center of the second subset of the plurality of photosensitive elements.

13. The stereoscopic imaging system of claim 1 , further comprising a housing having an upper surface and a lower surface spaced apart from the upper surface, wherein the first and second sets of optics and the image sensor are positioned between the upper surface and the lower surface.

14. The stereoscopic imaging system of claim 13 , wherein the upper surface of the housing includes a first aperture positioned to pass light from the scene to the first set of optics and a second aperture positioned to pass light from the scene to the second set of optics.

15. The stereoscopic imaging system of claim 13 , wherein a center of the first aperture is positioned a distance of 2-5 cm from a center of the second aperture.

16. The stereoscopic imaging system of claim 1 , wherein the first subset comprises a concave lens positioned along the first optical axis and a convex lens positioned along the second optical axis.

17. The stereoscopic imaging system of claim 1 , wherein each folded optic path comprises:
first and second prisms each comprising one of the first and second light folding surfaces;
a first lens having a first lens surface and a second lens surface positioned along the first optical axis; and
a group of lenses positioned along second optical axis between an output surface of the first prism and an input surface of the second prism, the group of lenses including a second lens having a third lens surface and a fourth lens surface, the third lens surface positioned to receive light from the output surface of the first prism,
wherein the first lens and the second lens comprise the first subset having telescopic optical characteristics.

18. The stereoscopic imaging system of claim 1 , wherein each folded optic path comprises:
first and second reflective mirrors each comprising one of the first and second light folding surfaces;
a first lens having a first lens surface and a second lens surface positioned along the first optical axis; and
a group of lenses positioned along second optical axis between the first and second reflective mirrors, the group of lenses including a second lens having a third lens surface and a fourth lens surface, the third lens surface positioned to receive light from the first reflective mirror,
wherein the first lens and the second lens comprise the first subset having telescopic optical characteristics.

19. The stereoscopic imaging system of claim 1 , wherein each of the first and second sets of optics comprises:
first and second reflective mirrors each comprising one of the first and second light folding surfaces;
a first wafer-level optical stack positioned along the first optical axis;
a second wafer-level optical stack positioned along the second optical axis to receive light from the first reflective mirror, the first and second lens wafer-level optical stacks comprising the first subset having inverted telescopic optical characteristics; and
at least one wafer-level optical stack positioned along the second optical axis to receive light passed through the second wafer-level optical stack.

20. The stereoscopic imaging system of claim 19 , further comprisin

Assignees

• Qualcomm Inc

Inventors

• Goma Sergiu Radu
• Georgiev Todor Georgiev
• Hseih Biay-Cheng
• Li Zheng-Wu
• Sun wen-yu

Classifications

• H04N25/76

  Addressed sensors, e.g. MOS or CMOS sensors · CPC title

• H04N23/55

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

• G02B3/0043

  Inhomogeneous or irregular arrays, e.g. varying shape, size, height · CPC title

• G02B17/0856

  comprising a refractive element with a reflective surface, the reflection taking place inside the element, e.g. Mangin mirrors · CPC title

• H04N13/271

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