Polarizer structure to control crosstalk in proximity sensor including a cover physically separates a photodetector from an object

Patent metadata

Field	Value
Publication number	US-9917582-B2
Application number	US-201514927711-A
Country	US
Kind code	B2
Filing date	Oct 30, 2015
Priority date	Oct 30, 2015
Publication date	Mar 13, 2018
Grant date	Mar 13, 2018

Abstract

An optical sensor, optical system, and proximity sensor are disclosed. An illustrative proximity sensor is disclosed to include a light source, a photodetector including a photo-sensitive area that receives incident light and converts the received incident light into an electrical signal, and a plurality of polarization layers stacked on the photodetector that limit light from becoming received incident light for the photo-sensitive area to light traveling toward the photodetector along a predetermined path.

First claim

What is claimed is:

1. An optical sensor, comprising:
a photodetector comprising a photo-sensitive area that receives incident light and converts the received incident light into an electrical signal;
a polarizer structure established on the photodetector that limits light from becoming received incident light for the photo-sensitive area to light traveling toward the photodetector along a predetermined path; and
a cover that physically separates the photodetector from an object and that intersects the predetermined path, wherein the polarizer structure enables the photodetector to account for the cover's contribution of light to the received incident light.

2. The optical sensor of claim 1 , wherein the predetermined path corresponds to a path traveled by light that reflects off the object.

3. The optical sensor of claim 2 , wherein the polarizer structure is established on a first portion of the photo-sensitive area and wherein a second portion of the photo-sensitive area is not covered by the polarizer structure.

4. The optical sensor of claim 3 , wherein the polarizer structure is established directly on the photodetector.

5. The optical sensor of claim 4 , wherein the polarizer structure comprises a plurality of metallization layers deposited directly on the photo-sensitive area of the photodetector.

6. The optical sensor of claim 5 , wherein the metallization layers are stacked substantially vertically on the photodetector.

7. The optical sensor of claim 5 , wherein the metallization layers are stacked in an offset configuration on the photodetector.

8. The optical sensor of claim 7 , further comprising:
a light source that emits light toward the object, wherein the metallization layers are offset such that crosstalk induced by the cover is substantially prohibited by the metallization layers of the polarizer structure.

9. An optical system, comprising:
a light source;
a photodetector comprising a photo-sensitive area that receives incident light and converts the received incident light into an electrical signal;
a polarizer structure established on the photodetector that limits light from becoming received incident light for the photo-sensitive area to light traveling toward the photodetector along a predetermined path; and
a cover that is positioned over both the light source and the photodetector, wherein the cover separates the light source and photodetector from an object, and wherein the polarizer structure substantially prohibits light reflecting from the cover to reach the photo-sensitive area as received incident light thereby enabling the prohibition of crosstalk that is induced by the cover.

10. The optical system of claim 9 , wherein the polarizer structure substantially prohibits crosstalk between the light source and photodetector.

11. The optical system of claim 10 , wherein the polarizer structure is established over less than all of the photo-sensitive area of the photodetector.

12. The optical system of claim 9 , wherein the polarizer structure is established directly on the photodetector.

13. The optical system of claim 12 , wherein the polarizer structure comprises a plurality of metallization layers deposited directly on the photo-sensitive area of the photodetector.

14. The optical system of claim 13 , wherein the metallization layers are stacked substantially vertically on the photodetector.

15. The optical system of claim 13 , wherein the metallization layers are stacked in an offset configuration on the photodetector.

16. A proximity sensor, comprising:
a light source;
a photodetector comprising a photo-sensitive area that receives incident light and converts the received incident light into an electrical signal; and
a plurality of polarization layers stacked on the photodetector that limit light from becoming received incident light for the photo-sensitive area to light traveling toward the photodetector along a predetermined path.

17. The proximity sensor of claim 16 , wherein the plurality of polarization layers comprise metallization layers.

18. The proximity sensor of claim 16 , wherein the plurality of polarization layers are stacked substantially vertically.

19. The proximity sensor of claim 16 , wherein some of the plurality of polarization layers are stacked substantially vertically and wherein others of the plurality of polarization layers are stacked in an offset configuration.

20. The proximity sensor of claim 19 , wherein the plurality of polarization layers that are stacked substantially vertically are positioned toward a center of the photodetector and wherein the others of the plurality of polarization layers that are stacked in the offset configuration are positioned away from the center of the photodetector.

Assignees

• Avago Technologies General Ip

Inventors

• Tan Wee Sin
• Lim John
• Neo Hui Ling
• Chan Serene
• Ramamoorthy Saravanan Rani

Classifications

• H03K2217/94112

  having more than one receiver · CPC title

• H03K2217/94108

  making use of reflection · CPC title

• G06F3/0421

  by interrupting or reflecting a light beam, e.g. optical touch-screen · CPC title

• H03K17/943 Primary

  using a plurality of optical emitters or detectors, e.g. keyboard · CPC title