Photosensor device and method for determining incident light

• US 8,878,132 B2
• Filed: 10/22/2012
• Issued: 11/04/2014
• Est. Priority Date: 10/25/2011
• Status: Active Grant

• Current Assignee: Pixart Imaging Incorporation ROC
• Original Assignee: Pixart Imaging Incorporation ROC
• Inventors: Hsu, En-Feng, Pang, Chin-Poh
• Primary Examiner(s): Kim, Kiho
• Application Number:
  US13/657,680
• Publication Number:
  US 20140110581A1
• Time in Patent Office: 743 Days
• Field of Search: 2503381-3385
• US Class Current: 250/338.4
• CPC Class Codes: G01J 1/0437 using masks, aperture plates, spatial light modulators, spatial filters, e.g. reflective filters
• CPC Class Codes: G01J 1/4204 with determination of ambient light solar light G01J2001/4266
• CPC Class Codes: G01J 1/4228 arrangements with two or more detectors, e.g. for sensitivity compensation
• CPC Class Codes: H01L 31/1013 devices sensitive to two or more wavelengths, e.g. multi-spectrum radiation detection devices

Abstract

A photosensor device includes a plurality of first well structures, a light shielding layer, and a plurality of second well structures. The first well structures are disposed in a substrate. The light shielding layer disposed is on the substrate; it covers a portion of the first well structures and exposes the rest portion of the first well structures. The covered first well structures are adjacent to the exposed first well structures exposed. The exposed first well structures generate a first photocurrent according to incident light. The second well structures generate a second photocurrent according to incident light. A total surface area of the second well structures is substantially equal to a total surface area of the exposed first well structures. A method for determining the incident light is also provided.

Claims

1. A photosensor device, comprising:

a plurality of first well structures, disposed in a first substrate;

a light shielding layer, covering a portion of the first well structures and exposing at least one first well structure, the first well structures covered by the light shielding layer being adjacent to the first well structure exposed by the light shielding layer, wherein the first well structure exposed by the light shielding layer is capable of generating a first photocurrent according to illumination of an incident light; and

at least one second well structure, disposed in a second substrate and capable of generating a second photocurrent according to illumination of the incident light, wherein a total surface area of the second well structure exposed under the incident light is equal to a total surface area of the first well structure exposed by the light shielding layer.

2. The photosensor device of claim 1, wherein the photosensor device respectively obtains a first spectrum signal and a second spectrum signal according to the first photocurrent and the second photocurrent.

3. The photosensor device of claim 2, wherein the photosensor device obtains a third spectrum signal by processing the first spectrum signal and the first spectrum signal.

4. The photosensor device of claim 3, wherein the third spectrum signal includes an infrared spectrum signal.

5. The photosensor device of claim 1, further comprising a signal processing circuit for obtaining a spectrum signal of the incident light by processing the first photocurrent and the second photocurrent.

6. The photosensor device of claim 5, wherein the signal processing circuit includes:

a multiplexor, including a first input terminal, a second input terminal, and an output terminal, wherein the first input terminal of the multiplexor is electrically connected with the first well structure exposed by the light shielding layer to receive the first photocurrent, and the second input terminal of the multiplexor is electrically connected with the second well structure to receive the second photocurrent;

a signal converter, including an input terminal and an output terminal, wherein the input terminal of the signal converter is electrically connected with the output terminal of the multiplexor; and

a processing unit, including an input terminal, wherein the output terminal of the signal converter is electrically connected with the input terminal of the processing unit.

7. The photosensor device of claim 1, wherein the first well structures and the at least one second well structure are disposed in the same substrate or different substrates.

8. The photosensor device of claim 1, wherein the first well structures and the at least one second well structure have the same or different conductivities.

9. The photosensor device of claim 1, wherein the first well structures covered by the light shielding layer are electrically connected with ground potential.

10. The photosensor device of claim 1, wherein an area of the first well structures exposed by the light shielding layer has a square or polygon opening shape.

11. The photosensor device of claim 1, wherein the first well structures covered by the light shielding layer and the first well structures exposed by the light shielding layer are disposed in alternating order.

12. The photosensor device of claim 1, wherein the first well structures covered by the light shielding layer surround the periphery of each of the first well structures exposed by the light shielding layer.

13. A photosensor device, comprising:

a plurality of first well structures;

an isolation well structure, disposed at a periphery of each of the first well structures to partition the first well structures, wherein the first well structures are capable of generating a first photocurrent according to illumination of an incident light; and

a plurality of second well structures, being capable of generating a second photocurrent according to the incident light, wherein a total surface area of the second well structures illuminated by the incident light is equal to a total surface area of the first well structures illuminated by the incident light.

14. The photosensor device of claim 13, wherein a depth of the isolation well structure is deeper than a depth of each of the first well structures.

15. The photosensor device of claim 13, wherein a width of the isolation well structure is smaller than or equal to a width of each of the first well structures.

16. The photosensor device of claim 13, wherein a doping concentration of the isolation well structure is substantially different from a doping concentration of the first well structures or a conductivity type of the isolation well structure is substantially different from a conductivity type of the first well structures.

17. The photosensor device of claim 13, wherein the isolation well structure is electrically connected with ground potential.

18. The photosensor device of claim 13, wherein the isolation well structure surrounds the periphery of each of the first well structures to partition the first well structures.

19. A method of determining an incident light, comprising:

receiving the incident light by at least one first well structure to generate a first photocurrent;

receiving the incident light by at least one second well structure to generate a second photocurrent; and

obtaining a spectrum signal of the incident light according to the first photocurrent and the second photocurrent;

wherein a total surface area of the second well structure or structures receiving the incident light is equal to a total surface area of the first well structure or structures receiving the incident light.

20. The method of claim 19, wherein the step of obtaining the spectrum signal of the incident light according to the first photocurrent and the second photocurrent comprising:

receiving the first photocurrent and the second photocurrent by a signal processing circuit; and

processing the first photocurrent and the second photocurrent by the signal processing circuit to respectively obtain a first spectrum signal and a second spectrum signal.

21. The method of claim 20, further comprising:

processing the first spectrum signal and the second spectrum signal to obtain an infrared spectrum signal.

22. The method of claim 21, wherein the step of processing the first spectrum signal and the second spectrum signal includes:

deducting the first spectrum signal from the second spectrum signal to obtain the infrared spectrum signal.

23. The method of claim 21, further comprising:

dividing one of the first spectrum signal and the second spectrum signal by the other to obtain the infrared spectrum signal.