Systems with integrated refractive and diffractive optics

Patent metadata

Field	Value
Publication number	US-10284825-B2
Application number	US-201615244297-A
Country	US
Kind code	B2
Filing date	Aug 23, 2016
Priority date	Sep 8, 2015
Publication date	May 7, 2019
Grant date	May 7, 2019

Abstract

An imaging system includes a refractive optical element and one or more diffractive optical gratings disposed over a two-dimensional array of photosensitive pixels. The different gratings present different patterns and features that are tailored to produce point-spread responses that emphasize different properties of an imaged scene. The different responses are captured by the pixels, and data captured from the responses can be used separately or together to analyze aspects of the scene. The imaging systems can include circuitry to analyze the image data, and to support modes that select between point-spread responses, selections of the pixels, and algorithms for analyzing image data.

First claim

The invention claimed is:

1. An optical system to sense incident light, the optical system comprising:
a photodetector array having a first array area and a second array area separate from the first array area;
a phase-grating layer overlying the photodetector array and including:
a grating area overlying the first array area to produce a diffractive response over the first array area; and
a null area overlying the second array area; and

a refractive optical element overlying the null area and the second array area to produce a refractive response over the second area.

2. The system of claim 1 , wherein the refractive optical element comprises a lens.

3. The system of claim 2 , further comprising a second lens aligned with the first-mentioned lens to produce the refractive response over the second area.

4. The system of claim 1 , wherein the null area comprises a hole in the phase-grating layer.

5. The system of claim 2 , wherein the grating area includes a phase-grating pattern and the null area includes a smooth surface opposite the photodetector array.

6. The system of claim 5 , wherein the null area includes a second smooth surface opposite the photodetector array.

7. The system of claim 5 , wherein the smooth surface is flat.

8. The system of claim 1 , wherein the phase-grating layer includes a phase grating that defines a transverse plane opposite the photodetector array, the phase grating spaced from the array and having boundaries of odd symmetry, each boundary defined by:
a first phase-grating feature extending along the respective boundary in the transverse plane, each first phase-grating feature including a first segment adjacent the boundary and of a first width W1 in a dimension perpendicular to the boundary and within the plane, a second segment adjacent the first segment and opposite the boundary, the second segment of a second width W2 different from the first width in the dimension, and a third second segment adjacent the second segment and opposite the boundary, the third segment of a third width W3 in the dimension; and
a second phase-grating feature extending along the respective boundary in the transverse plane, each second phase-grating feature including a first segment adjacent the boundary and of the first width W1 in the dimension perpendicular to the boundary and within the plane, a second segment adjacent the first segment and opposite the boundary, the second segment of the second width W2 in the dimension, and a third second segment adjacent the second segment and opposite the boundary, the third segment of the third width W3 in the dimension.

9. The system of claim 1 , further comprising an aperture layer having a first aperture limiting the incident light from the phase grating to the first array area and a second aperture limiting the incident light from the refractive optical element to the second array area.

10. The system of claim 1 , wherein the phase grating is one of multiple phase gratings each producing a respective diffractive response over respective areas of the photodetector array.

11. The system of claim 10 , wherein the different phase gratings capture different ranges of angles of incidence for the incident light.

12. The system of claim 10 , wherein the different phase gratings exhibit different and respective point spread responses to the incident light.

13. The system of claim 1 , wherein the phase grating includes boundaries of odd symmetry each defined by adjacent first and second features of odd symmetry located respectively to each side of that boundary so as to induce, at a position immediately below the first and second features, for light in a wavelength band of interest incident the grating, a half-wavelength shift with respect to each other for the light passing through the adjacent first and second features, resulting in curtains of minimum intensity at the photodetector array underlying that boundary.

14. The system of claim 1 , further comprising an infrared filter to block infrared components of the incident light from impinging upon only one of the first array area and the second array area.

15. A method of detecting properties of a scene using a monolithic photosensitive array, the method comprising:
receiving light in a wavelength band of interest from the scene at a diffractive optic casting a diffractive response to the light over a first area of the array;
receiving the light from the scene at a refractive optic casting a refractive response to the light over a second area of the array;
sampling the diffractive response to obtain diffractive-response data; and
sampling the refractive response to obtain refractive-response data.

16. The method of claim 15 , further comprising determining whether to sample the refractive response based on the diffractive response data.

17. The method of claim 15 , wherein the diffractive-response data represents an image of the scene that is unintelligible to a human observer.

18. The method of claim 17 , wherein the refractive-response data represents a color image of the scene.

19. The method of claim 17 , wherein sampling the diffractive response comprising acquiring successive frames of the diffractive response, the method further comprising comparing the successive frames to detective movement within the scene.

20. The method of claim 15 , further comprising:
receiving the light from the scene at a second diffractive optic casting a second diffractive response to the light over a third area of the array; and
sampling the second diffractive response to obtain second diffractive-response data.

Assignees

• Rambus Inc

Inventors

• Endsley Jay

Classifications

• H04N23/56

  provided with illuminating means · CPC title

• H04N23/54 Primary

  Mounting of pick-up tubes, electronic image sensors, deviation or focusing coils · CPC title

• H04N5/2254

  Electricity · mapped topic

• H04N9/045 Primary

  Electricity · mapped topic

• G02B13/16 Primary

  for use in conjunction with image converters or intensifiers {, or for use with projectors, e.g. objectives for projection TV} · CPC title