Method and apparatus for optical detector with special discrimination

• US 6,596,981 B1
• Filed: 01/14/2002
• Issued: 07/22/2003
• Est. Priority Date: 01/14/2002
• Status: Expired due to Term

• Current Assignee: Texas Advanced Optoelectronic Solutions Incorporated (Ams-Osram AG)
• Original Assignee: Texas Advanced Optoelectronic Solutions Incorporated (Ams-Osram AG)
• Inventors: Aswell, Cecil, Berlien, Jr., John H., Dierschke, Eugene G., Hodson, Lester L.
• Primary Examiner(s): PYO, KEVIN K
• Application Number:
  US10/047,484
• Publication Number:
  US 20030132369A1
• Time in Patent Office: 554 Days
• Field of Search: 250/208.1, 250/214.1, 257/291, 257/294, 257/431, 257/434, 257/435, 257/440
• US Class Current: 250/214.1
• CPC Class Codes: G01J 1/0488 with spectral filtering
• 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: G01J 2001/4247 for testing lamps or other light sources
• CPC Class Codes: G01J 3/2803 using photoelectric array detector
• CPC Class Codes: H01L 27/1446 in a repetitive configuration
• CPC Class Codes: H01L 31/02164 for shielding light, e.g. light blocking layers, cold shields for infrared detectors
• CPC Class Codes: H01L 31/103 the potential barrier being of the PN homojunction type

Abstract

A monolithic optical detector for determining spectral content of an incident light includes at least a first and second well in a substrate, the second well formed proximate the first well. The first well is configured to be exposed to incident light and for generating a first photocurrent as a function of the incident light. The second well is configured to be shielded from the incident light and for generating a second photocurrent as a function of the incident light. Lastly, a processing and control unit, responsive to the first and second photocurrents, determines an indication of spectral content of the incident light. A method and device parameter controller are also disclosed.

Claims

1. A monolithic optical detector comprising:

a first well in a substrate, said first well configured to be exposed to incident light and for generating a first photocurrent as a function of the incident light;

a second well in the substrate, proximate said first well, said second well configured to be shielded from the incident light and for generating a second photocurrent as a function of the incident light; and

means, responsive to the first and second photocurrents, for determining an indication of spectral content of the incident light.

2. The detector of claim 1, wherein said means for determining the indication of spectral content includes determining a ratio of the first and second photocurrents, wherein the ratio provides a measure of spectral content.

3. The detector of claim 2, wherein the ratio further includes at least one of a first measurement range representative of a first type of incident light, a second measurement range representative of a second type of incident light, and a third measurement range representative of a third type of incident light.

4. The detector of claim 3, wherein the first, second, and third type of incident light include at least one of fluorescent light, incandescent light, and sun light.

5. The detector of claim 1, wherein said first and second wells include at least one of n-type wells in a p-type substrate, p-type wells in an n-type substrate, shallow diffusions, deep diffusions, combinations of shallow and deep diffusions, source/drain diffusions, and charge gate MOS diode structures.

6. The detector of claim 1, further wherein said first and second wells include wells of substantially similar dimensions.

7. The detector of claim 1, wherein the indication of spectral content includes a wavelength.

8. The detector of claim 1, further comprising:

means for calibrating at least one of the first and second photocurrents.

9. The detector of claim 1, further comprising:

at least one transparent dielectric layer disposed above at least said first well; and

at least one opaque layer disposed above said second well.

10. The detector of claim 9, wherein the at least one opaque layer includes a conductive layer.

11. The detector of claim 1, further comprising:

at least one additional well in the substrate, proximate said first and second wells, said at least one additional well configured to be shielded from the incident light and for generating at least one additional photocurrent as a function of the incident light, respectively; and

wherein said means for determining the indication of spectral content includes means, responsive further to the at least one additional photocurrent, for determining the indication of spectral content of the incident light.

12. The detector of claim 11, wherein said means for determining the indication of spectral content includes determining a ratio of the first and second photocurrents, the ratio providing a measure of spectral content, further including determining at least one additional ratio of the second and at least one additional photocurrents, wherein the at least one additional ratio provides an additional measure of spectral content of the incident light.

13. The detector of claim 12, wherein the ratio and at least one additional ratio further include at least one of a first measurement range representative of a first type of incident light, a second measurement range representative of a second type of incident light, and a third measurement range representative of a third type of incident light, respectively.

14. The detector of claim 13, wherein the first, second, and third type of incident light include at least one of fluorescent light, incandescent light, and sun light.

15. The detector of claim 11, further wherein said first, second, and at least one additional wells include wells of substantially similar dimensions.

16. The detector of claim 1, further comprising:

at least one analog-to-digital (A/D) converter integrated with said first and second wells and formed as a monolithic integrated circuit, said first and second wells being coupled to at least one input of said at least one A/D converter for converting a respective one of the first and second photocurrent into a digital output.

17. The detector of claim 16, wherein further comprising:

a multiplexer coupled between said first and second wells and an input of said A/D converter, said multiplexer for selectively coupling the first and second photocurrents to the input of said A/D converter.

18. The detector of claim 16, wherein said at least one A/D converter integrates a respective one of the first and second photocurrents over a sufficient time period to average a ripple in the incident light caused by alternating current (AC) lighting.

19. The detector of claim 16, further comprising:

means, coupled to an output of said at least one A/D converter and implemented on the monolithic integrated circuit, for establishing a spectral content response configured to simulate that which would be observed by a human eye.

20. The detector of claim 16, wherein said at least one A/D converter utilizes a logarithmic compression for extending a dynamic range of a photocurrent received at the at least one input of said at least one A/D converter.

21. The detector of claim 1, further comprising:

means, coupled to said determining means, for controlling a device parameter in response to the indication of spectral content of the incident light.

22. The detector of claim 21, wherein the device parameter includes at least one of a backlight control parameter of a display and a color control parameter of a color display.

23. The detector of claim 22, wherein the backlight control parameter includes at least a first artificial illumination level for a first type of incident light and a second artificial illumination level for a second type of incident light.

24. The detector of claim 1, wherein said first well includes a plurality of first wells, the plurality of first wells for generating a plurality of first photo currents as a function of the incident light,

wherein said second well includes a plurality of second wells, the plurality of second wells for generating a plurality of second photo currents as a function of the incident light, and

wherein said determining means determines an indication of spectral content of the incident light in response to the plurality of first photo currents and the plurality of second photo currents.

25. The detector of claim 24, wherein the plurality of first wells further includes an array of first wells and the plurality of second wells further includes an array of second wells proximate respective ones of the array of first wells.

26. The detector of claim 25, still further wherein the array of first wells and the array of second wells include repetitive arrays.

27. The detector of claim 25, wherein the arrays of first and second wells form a concentric geometry of first and second wells.

28. A method for determining spectral content of incident light upon a monolithic optical detector comprising:

generating a first photocurrent as a function of the incident light at a first well in a substrate, the first well configured to be exposed to incident light;

generating a second photocurrent as a function of the incident light at a second well in the substrate proximate the first well, the second well configured to be shielded from the incident light; and

determining an indication of spectral content of the incident light in response to the first and second photocurrents.

29. The method of claim 28, wherein determining the indication of spectral content includes determining a ratio of the first and second photocurrents, wherein the ratio provides a measure of spectral content.

30. The method of claim 29, wherein the ratio further includes at least one of a first measurement range representative of a first type of incident light, a second measurement range representative of a second type of incident light, and a third measurement range representative of a third type of incident light.

31. The method of claim 30, wherein the first, second, and third type of incident light include at least one of fluorescent light, incandescent light, and sun light.

32. The method of claim 28, wherein the first and second wells include at least one of n-type wells in a p-type substrate, p-type wells in an n-type substrate, shallow diffusions, deep diffusions, combinations of shallow and deep diffusions, source/drain diffusions, and charge gate MOS diode structures.

33. The method of claim 28, further wherein the first and second wells include wells of substantially similar dimensions.

34. The method of claim 28, wherein the indication of spectral content includes a wavelength.

35. The method of claim 28, further comprising calibrating at least one of the first and second photocurrents.

36. The method of claim 28, further comprising:

disposing at least one transparent dielectric layer above at least the first well; and

disposing at least one opaque layer above the second well.

37. The method of claim 36, wherein the at least one opaque layer includes a conductive layer.

38. The method of claim 28, further comprising:

generating at least one additional photocurrent as a function of the incident light at an at least one additional well in the substrate, proximate the first and second wells, the at least one additional well configured to be shielded from the incident light, respectively; and

wherein determining the indication of spectral content includes determining the indication of spectral content of the incident light, further in response to the at least one additional photocurrent.

39. The method of claim 38, wherein determining the indication of spectral content includes determining a ratio of the first and second photocurrents, the ratio providing a measure of spectral content, further including determining at least one additional ratio of the second and at least one additional photocurrents, wherein the at least one additional ratio provides an additional measure of spectral content of the incident light.

40. The method of claim 39, wherein the ratio and at least one additional ratio further include at least one of a first measurement range representative of a first type of incident light, a second measurement range representative of a second type of incident light, and a third measurement range representative of a third type of incident light, respectively.

41. The method of claim 40, wherein the first, second, and third type of incident light include at least one of fluorescent light, incandescent light, and sun light.

42. The method of claim 38, further wherein said first, second, and at least one additional wells include wells of substantially similar dimensions.

43. The method of claim 28, further comprising:

providing at least one analog-to-digital (A/D) converter with the first and second wells to form a monolithic integrated circuit, the first and second wells being coupled to at least one input of the at least one A/D converter for converting a respective one of the first and second photocurrent into a digital output.

44. The method of claim 43, further comprising:

selectively multiplexing the first and second photocurrents of the first and second wells, respectively, to an input of the A/D converter.

45. The method of claim 43, wherein the at least one A/D converter integrates a respective one of the first and second photocurrents over a sufficient time period to average a ripple in the incident light caused by alternating current (AC) lighting.

46. The method of claim 43, further comprising:

establishing a spectral content response based on an output of the at least one A/D converter, the spectral content response configured to simulate that which would be observed by a human eye.

47. The method of claim 43, wherein the at least one A/D converter utilizes a logarithmic compression for extending a dynamic range of a photocurrent received at the at least one input of said at least one A/D converter.

48. The method of claim 28, further comprising:

controlling a device parameter in response to the indication of spectral content of the incident light.

49. The method of claim 48, wherein the device parameter includes at least one of a backlight control parameter of a display and a color control parameter of a color display.

50. The method of claim 49, wherein the backlight control parameter includes at least a first artificial illumination level for a first type of incident light and a second artificial illumination level for a second type of incident light.

51. The method of claim 28, wherein the first well includes a plurality of first wells, the plurality of first wells for generating a plurality of first photo currents as a function of the incident light,

wherein the second well includes a plurality of second wells, the plurality of second wells for generating a plurality of second photo currents as a function of the incident light, and

wherein the indication of spectral content of the incident light is determined in response to the plurality of first photo currents and the plurality of second photo currents.

52. The detector of claim 51, wherein the plurality of first wells further includes an array of first wells and the plurality of second wells further includes an array of second wells proximate respective ones of the array of first wells.

53. The detector of claim 52, still further wherein the array of first wells and the array of second wells include repetitive arrays.

54. The detector of claim 52, wherein the arrays of first and second wells form a concentric geometry of first and second wells.

55. A display controller comprising:

a monolithic optical detector including first and second wells in a substrate, the second well proximate the first well, the first well configured to be exposed to incident light and for generating a first photocurrent as a function of the incident light, the second well configured to be shielded from the incident light and for generating a second photocurrent as a function of the incident light, said monolithic optical detector further including means, responsive to the first and second photocurrents, for determining an indication of spectral content of the incident light; and

a backlight controller responsive to the indication of spectral content of the incident light for controlling a backlighting of a display.