Image sensor with improved light sensitivity

• US 8,330,839 B2
• Filed: 03/19/2012
• Issued: 12/11/2012
• Est. Priority Date: 07/28/2005
• Status: Active Grant

• Current Assignee: Omnivision Technologies Incorporated (Will Semiconductor Co., Ltd. Shanghai)
• Original Assignee: Omnivision Technologies Incorporated (Will Semiconductor Co., Ltd. Shanghai)
• Inventors: Compton, John T., Hamilton, John F. Jr.
• Primary Examiner(s): Tran, Sinh
• Assistant Examiner(s): FLOHRE, JASON A
• Application Number:
  US13/424,138
• Publication Number:
  US 20120176521A1
• Time in Patent Office: 267 Days
• Field of Search: 348/276, 348/279
• US Class Current: 348/277
• CPC Class Codes: H04N 23/633 for displaying additional information relating to control or operation of the camera
• CPC Class Codes: H04N 23/843 Demosaicing, e.g. interpolating colour pixel values
• CPC Class Codes: H04N 25/133 including elements passing panchromatic light, e.g. filters passing white light
• CPC Class Codes: H04N 25/134 based on three different wavelength filter elements
• CPC Class Codes: H04N 25/136 using complementary colours

Abstract

An image sensor for capturing a color image is disclosed having a two-dimensional array having first and second groups of pixels wherein pixels from the first group of pixels have narrower spectral photoresponses than pixels from the second group of pixels and wherein the first group of pixels has individual pixels that have spectral photoresponses that correspond to a set of at least two colors. Further, the placement of the first and second groups of pixels defines a pattern that has a minimal repeating unit including at least twelve pixels. The minimal repeating unit has a plurality of cells wherein each cell has at least two pixels representing a specific color selected from the first group of pixels and a plurality of pixels selected from the second group of pixels arranged to permit the reproduction of a captured color image under different lighting conditions.

Claims

1. A system for capturing a color image, the system comprising:

a two-dimensional array having first and second groups of pixels wherein pixels from the first group of pixels have narrower spectral photoresponses than pixels from the second group of pixels and wherein the first group of pixels has individual pixels that have spectral photoresponses that correspond to a set of at least two colors;

the placement of the first and second groups of pixels in the array defining a pattern that has a plurality of tiled minimal repeating units each including at least twelve pixels, the minimal repeating unit having a plurality of non-overlapping cells wherein each cell has at least two pixels representing a specific color selected from the first group of pixels and a plurality of pixels selected from the second group of pixels arranged to permit the reproduction of a captured color image under different lighting conditions; and

means of combining at least two of the specific color pixels within each cell.

2. The system of claim 1 wherein the minimal repeating unit has at least three cells.

3. The system of claim 1 wherein the minimal repeating unit has at least three cells, with at least one cell of a first color having at least two pixels of the first color, at least one cell of a second color having at least two pixels of the second color, and at least one cell of a third color having at least two pixels of the third color.

4. The system of claim 3 wherein the first color is green, the second color is red, and the third color is blue, or wherein the first color is cyan, the second color is magenta, and the third color is yellow.

5. The system of claim 1 wherein the minimal repeating unit includes at least four cells and wherein:

the cells include at least one green cell having at least two green pixels, at least one red cell having at least two red pixels, and at least one blue cell having at least two blue pixels;

or

the cells include at least two green cells each having at least two green pixels, at least one red cell having at least two red pixels, and at least one blue cell having at least two blue pixels.

6. The system of claim 1 wherein the image array is composed of active pixels or charge coupled device pixels.

7. The system of claim 6 wherein a color filter corresponding to the desired color is provided for each color pixel in the first group of pixels.

8. The system of claim 6 wherein the second group of pixels each include a neutral density filter.

9. The system of claim 1 wherein the minimal repeating unit is

10. The system of claim 9 wherein A, B, and C are individually selected from red, green, or blue.

11. The system of claim 9 wherein A, B, and C are each respectively red, green, and blue.

12. The image sensor of claim 9 wherein A, B, and C are individually selected from cyan, magenta, or yellow.

13. The image sensor of claim 9 wherein A, B, and C are each respectively cyan, yellow, and magenta.

14. The system of claim 1 wherein the minimal repeating unit is

15. The system of claim 14 wherein A, B, and C are individually selected from red, green, or blue.

16. The system of claim 14 wherein A, B, and C are each respectively red, green, and blue.

17. The image sensor of claim 14 wherein A, B, and C are individually selected from cyan, magenta, or yellow.

18. The image sensor of claim 14 wherein A, B, and C are each respectively cyan, yellow, and magenta.

19. The system of claim 1 wherein the minimal repeating unit is

20. The image sensor of claim 19 wherein A, B, and C are individually selected from red, green, or blue.

21. The image sensor of claim 19 wherein A, B, and C are each respectively red, green, and blue.

22. The image sensor of claim 19 wherein A, B, and C are individually selected from cyan, magenta, or yellow.

23. The image sensor of claim 19 wherein A, B, and C are each respectively cyan, yellow, and magenta.

24. The system of claim 1 wherein the minimal repeating unit is

25. The image sensor of claim 24 wherein A, B, and C are individually selected from red, green, or blue.

26. The image sensor of claim 24 wherein A, B, and C are each respectively red, green, and blue.

27. The image sensor of claim 24 wherein A, B, and C are individually selected from cyan, magenta, or yellow.

28. The image sensor of claim 24 wherein A, B, and C are each respectively cyan, yellow, and magenta.

29. A system for capturing a color image, the system comprising:

a two-dimensional array having first and second groups of pixels wherein pixels from the first group of pixels have narrower spectral photoresponses than pixels from the second group of pixels and wherein the first group of pixels has individual pixels that have spectral photoresponses that correspond to a set of at least two colors;

the placement of the first and second groups of pixels in the array defining a pattern that has a plurality of tiled minimal repeating units each including at least twelve pixels and having a plurality of non-overlapping cells, wherein each cell has at least two rows and at least two columns, each column including at least one pixel representing a specific color selected from the first group of pixels and at least one pixel selected from the second group of pixels arranged to permit the reproduction of a captured color image under different lighting conditions; and

means of combining at least two of the specific color pixels within each cell.

30. The system of claim 29 wherein the minimal repeating unit has at least three cells.

31. The system of claim 29 wherein the minimal repeating unit has at least three cells, with at least one cell of a first color having at least one pixel of the first color, at least one cell of a second color having at least one pixel of the second color, and at least one cell of a third color having at least one pixel of the third color.

32. The system of claim 31 wherein the first color is green, the second color is red, and the third color is blue, or wherein the first color is cyan, the second color is magenta, and the third color is yellow.

33. The system of claim 29 wherein the minimal repeating unit includes at least four cells and wherein:

the cells include at least one green cell having at least one green pixel, at least one red cell having at least one red pixel, and at least one blue cell having at least one blue pixel;

or

the cells include at least two green cells each having at least one green pixel, at least one red cell having at least one red pixel, and at least one blue cell having at least one blue pixel.

34. The system of claim 29 wherein the image array is composed of active pixels or charge coupled device pixels.

35. The system of claim 34 wherein a color filter corresponding to the desired color is provided for each color pixel in the first group of pixels.

36. The system of claim 34 wherein the second group of pixels each include a neutral density filter.

37. The system of claim 29 wherein the minimal repeating unit is

38. The system of claim 37 wherein A, B, and C are individually selected from red, green, or blue.

39. The system of claim 37 wherein A, B, and C are each respectively red, green, and blue.

40. The image sensor of claim 37 wherein A, B, and C are individually selected from cyan, magenta, or yellow.

41. The image sensor of claim 37 wherein A, B, and C are each respectively cyan, yellow, and magenta.

42. The system of claim 29 wherein the minimal repeating unit is

43. The system of claim 42 wherein A, B, and C are individually selected from red, green, or blue.

44. The system of claim 42 wherein A, B, and C are each respectively red, green, and blue.

45. The image sensor of claim 42 wherein A, B, and C are individually selected from cyan, magenta, or yellow.

46. The image sensor of claim 42 wherein A, B, and C are each respectively cyan, yellow, and magenta.

47. The system of claim 29 wherein the minimal repeating unit is

48. The image sensor of claim 47 wherein A, B, and C are individually selected from red, green, or blue.

49. The image sensor of claim 47 wherein A, B, and C are each respectively red, green, and blue.

50. The image sensor of claim 47 wherein A, B, and C are individually selected from cyan, magenta, or yellow.

51. The image sensor of claim 47 wherein A, B, and C are each respectively cyan, yellow, and magenta.

52. The system of claim 29 wherein the minimal repeating unit is

53. The image sensor of claim 52 wherein A, B, and C are individually selected from red, green, or blue.

54. The image sensor of claim 52 wherein A, B, and C are each respectively red, green, and blue.

55. The image sensor of claim 52 wherein A, B, and C are individually selected from cyan, magenta, or yellow.

56. The image sensor of claim 52 wherein A, B, and C are each respectively cyan, yellow, and magenta.

57. A system for capturing a color image, the system comprising:

a two-dimensional array having first and second groups of pixels wherein pixels from the first group of pixels have narrower spectral photoresponses than pixels from the second group of pixels and wherein the first group of pixels has individual pixels that have spectral photoresponses that correspond to a set of at least two colors;

the placement of the first and second groups of pixels in the array defining a pattern that has a plurality of tiled minimal repeating units each including at least twelve pixels, the minimal repeating unit having a plurality of non-overlapping cells, wherein a diagonal of each cell includes at least one pixel selected from the second group and at least one pixel of at least one color selected from the first group, or wherein the diagonal of each cell excludes pixels selected from the second group; and

means of combining at least two of the specific color pixels within each cell.

58. The system of claim 57 wherein another diagonal of each cell includes only pixels selected from the second group.

59. The system of claim 57 wherein another diagonal of each cell includes one or more pixels selected from the second group and one or more pixels of one or more colors selected from the first group.

60. The system of claim 57 wherein another diagonal of each cell includes only pixels of one or more colors selected from the second group.

61. The system of claim 57 wherein the minimal repeating unit is

62. The system of claim 61 wherein A, B, and C are individually selected from red, green, or blue.

63. The system of claim 61 wherein A, B, and C are each respectively red, green, and blue.

64. The image sensor of claim 61 wherein A, B, and C are individually selected from cyan, magenta, or yellow.

65. The image sensor of claim 61 wherein A, B, and C are each respectively cyan, yellow, and magenta.

66. The system of claim 57 wherein the minimal repeating unit is

67. The system of claim 66 wherein A, B, and C are individually selected from red, green, or blue.

68. The system of claim 66 wherein A, B, and C are each respectively red, green, and blue.

69. The image sensor of claim 66 wherein A, B, and C are individually selected from cyan, magenta, or yellow.

70. The image sensor of claim 66 wherein A, B, and C are each respectively cyan, yellow, and magenta.