Polarization selective, frequency selective, and wide dynamic range detectors, imaging arrays, readout integrated circuits, and sensor systems

• US 10,323,987 B2
• Filed: 01/17/2018
• Issued: 06/18/2019
• Est. Priority Date: 01/09/2015
• Status: Active Grant

• Current Assignee: Apple Inc.
• Original Assignee: Apple Inc.
• Inventors: Kangas, Miikka M., Bishop, Michael J., Chen, Robert, Simon, David I., Sontag, III, Harold L., Skidmore, George Dee
• Primary Examiner(s): Punnoose, Roy M
• Application Number:
  US15/873,795
• Publication Number:
  US 20180143078A1
• Time in Patent Office: 517 Days
• Field of Search: 356370
• CPC Class Codes: G01J 2005/202 Arrays
• CPC Class Codes: G01J 4/04 Polarimeters using electric detection means G01J4/02 takes precedence
• CPC Class Codes: G01J 5/0225 Shape of the cavity itself or of elements contained in or suspended over the cavity
• CPC Class Codes: G01J 5/0846 having multiple detectors for performing different types of detection, e.g. using radiometry and reflectometry channels
• CPC Class Codes: G01J 5/0853 having infrared absorbers other than the usual absorber layers deposited on infrared detectors like bolometers, wherein the heat propagation between the absorber and the detecting element occurs within a solid
• CPC Class Codes: G01J 5/20 using resistors, thermistors or semiconductors sensitive to radiation, e.g. photoconductive devices
• CPC Class Codes: G01J 5/59 using polarisation; Details thereof

Abstract

This relates to sensor systems, detectors, imagers, and readout integrated circuits (ROICs) configured to selectively detect one or more frequencies or polarizations of light, capable of operating with a wide dynamic range, or any combination thereof. In some examples, the detector can include one or more light absorbers; the patterns and/or properties of a light absorber can be configured based on the desired measurement wavelength range and/or polarization direction. In some examples, the detector can comprise a plurality of at least partially overlapping light absorbers for enhanced dynamic range detection. In some examples, the detector can be capable of electrostatic tuning for one or more flux levels by varying the response time or sensitivity to account for various flux levels. In some examples, the ROIC can be capable of dynamically adjusting at least one of the frame rate integrating capacitance, and power of the illumination source.

Claims

1. A light detector comprising:

a plurality of light absorbers including;

a first light absorber configured to absorb light, and

a second light absorber configured to absorb light,

wherein the first light absorber is thermally coupled to the second light absorber;

at least one electrical isolator configured to electrically isolate the first light absorber from the second light absorber; and

a sensor thermally coupled to the first light absorber and second light absorber, wherein the sensor is configured to generate one or more signals indicative of the absorbed light.

2. The light detector of claim 1, wherein the at least one electrical isolator includes:

a first electrical insulator coupled to the first light absorber, and

a second electrical insulator coupled to the second light absorber.

3. The light detector of claim 1, further comprising:

a plurality of posts including;

a first post configured to thermally couple the first light absorber to the sensor, and

a second post configured to thermally couple the second light absorber to the sensor.

4. The light detector of claim 3,

wherein the plurality of light absorbers further include:

a third light absorber configured to absorb light, and

a fourth light absorber configured to absorb light,

the first, second, third, and fourth light absorbers thermally coupled together,

wherein the plurality of posts further includes;

a third post configured to thermally couple the third light absorber to the sensor, and

a fourth post configured to thermally couple the fourth light absorber to the sensor.

5. The light detector of claim 4, wherein:

each of the plurality of posts is located at a unique corner of the respective light absorber, and

the plurality of light absorbers fan out from a center of the light detector.

6. The light detector of claim 1, wherein the plurality of light absorbers includes a plurality of wires that form a capacitive resonant mesh, wherein the absorbed light is selected based on at least a spacing of the plurality of wires.

7. The light detector of claim 1, where the plurality of light absorbers is configured to select the absorbed light from a range of wavelengths, wherein the range of wavelengths is associated with lengths of edges of the plurality of light absorbers and a spacing of a plurality of features included in the plurality of light absorbers.

8. The light detector of claim 1, further comprising:

a reflector configured to reflect incident light, wherein the reflector is thermally coupled to the plurality of light absorbers,

wherein the sensor is thermally coupled to the plurality of light absorbers through the reflector.

9. The light detector of claim 8, wherein an absorbing surface of at least one of the plurality of light absorbers faces the reflector.

10. The light detector of claim 8, wherein a distance between an absorbing surface of at least one of the plurality of light absorbers and the reflector is equal to a quarter of a wavelength of the absorbed light.

11. The light detector of claim 1, wherein the plurality of light absorbers are plate absorbers.

12. The light detector of claim 1, wherein the at least one electrical isolator is an encapsulation further configured to thermally couple the plurality of light absorbers to the sensor.

13. The light detector of claim 1, further comprising:

a plurality of another light absorbers including;

a fifth light absorber configured to absorb light, and

a sixth light absorber configured to absorb light; and

at least one another electrical isolator configured to electrically isolate the fifth light absorber from the sixth light absorber,

wherein the plurality of another light absorbers is located on a different layer than the plurality of light absorbers, and

wherein the sensor is thermally coupled to the fifth light absorber and the sixth light absorber.

14. An imager comprising:

an array of detector pixels, each detector pixel including;

a plurality of first light absorbers thermally coupled together, each first light absorber configured to absorb light,

at least one electrical isolator configured to electrically isolate the plurality of first light absorbers from each other, and

a first sensor thermally coupled to the plurality of first light absorbers;

a plurality of contacts configured to transmit signals to and from the array of detector pixels to an integrated circuit; and

the integrated circuit configured to;

receive signals indicative of the absorbed light, and

transmit signals to control operation of the array of detector pixels.

15. The imager of claim 14, wherein at least one detector pixel further includes:

a plurality of posts, each post configured to thermally couple a respective one of the plurality of first light absorbers to the respective first sensor included in the at least one detector pixel.

16. The imager of claim 15, wherein for the at least one detector pixel:

each of the plurality of posts is located at a corner of one of the plurality of first light absorbers,

the plurality of posts are located at different corners of the plurality of first light absorbers, and

the plurality of first light absorbers fan out from a center of the at least one detector pixel.

17. The light detector of claim 14, further comprising:

a second light absorber located on a different layer than the plurality of first light absorbers; and

a second sensor thermally coupled to the second light absorber.

18. A method for operating a light detector, the method comprising:

electrically isolating a plurality of light absorbers from each other;

thermally coupling the plurality of light absorbers to each other and to a sensor;

biasing the plurality of light absorbers; and

measuring one or more of a change in resistance and a change in temperature of the plurality of light absorbers using the sensor, wherein the measured change is indicative of an absorption of incident light by the light detector.

19. The method of claim 18, further comprising:

redirecting the incident light using a reflector to the plurality of light absorbers, wherein the plurality of light absorbers are thermally coupled to the sensor using the reflector.

20. The method of claim 18, wherein the plurality of light absorbers are electrically isolated from each other using an encapsulation, and further wherein the plurality of light absorbers are thermally coupled to each other and to the sensor using the encapsulation.