Image sensor with improved light sensitivity

• US 7,916,362 B2
• Filed: 05/22/2006
• Issued: 03/29/2011
• Est. Priority Date: 05/22/2006
• Status: Active Grant

• Current Assignee: Omnivision Technologies Incorporated (Will Semiconductor Co., Ltd. Shanghai)
• Original Assignee: Eastman Kodak Company
• Inventors: Nakamura, Hideo, DeWeese, Thomas E., Kijima, Takayuki, Hamilton, John F. Jr., Compton, John T.
• Primary Examiner(s): Zimmerman; Mark K
• Assistant Examiner(s): Sabah; Haris
• Application Number:
  US11/419,574
• Publication Number:
  US 20070268533A1
• Time in Patent Office: 1,772 Days
• Field of Search: 358/500, 358/515, 358/514, 348/234, 348/265, 348/678
• US Class Current: 358/500
• CPC Class Codes: H04N 23/843 Demosaicing, e.g. interpolating colour pixel values
• CPC Class Codes: H04N 25/00 Circuitry of solid-state image sensors [SSIS]; Control thereof
• 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, with the placement of the first and second groups of pixels defining a pattern that has a minimal repeating unit including at least six pixels with at least some rows or columns of the minimal repeating unit composed only of pixels from the second group of pixels, and including ways to combine similarly positioned pixels from at least two adjacent minimal repeating units.

Claims

1. An image sensor for capturing a color image, comprising:

a) a two-dimensional array having first and second groups of pixels, arranged in rows and columns, 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 pixels that have spectral photoresponses that correspond to a set of at least two colors;

b) the placement of the first and second groups of pixels defining a pattern that has a minimal repeating unit including at least six pixels, so that at least some rows or columns of the minimal repeating unit are composed only of pixels from the second group,

c) means for combining similarly positioned pixels from at least two adjacent minimal repeating units, and

d) wherein the minimal repeating unit of the image sensor is;

2. The image sensor of claim 1 wherein pixels are combined by binning the charge from the pixels, by averaging the voltages produced by the pixels, or by first converting the pixel values to digital numbers and then combining the digital numbers, or combinations thereof.

3. The image sensor of claim 2 wherein the voltages are averaged by first charging capacitors to the voltages produced by the pixels and then connecting the capacitors together to average the voltages, with the capacitors being of equal sizes to perform a simple average or of differing sizes to perform a weighted average.

4. An image sensor for capturing a color image, comprising:

a) a two-dimensional array having first and second groups of pixels, arranged in rows and columns, 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 pixels that have spectral photoresponses that correspond to a set of at least two colors;

b) the placement of the first and second groups of pixels defining a pattern that has a minimal repeating unit including at least six pixels, so that at least some rows or columns of the minimal repeating unit are composed only of pixels from the second group,

c) means for combining pixels of like color from at least three adjacent minimal repeating units, and

d) wherein the minimal repeating unit of the image sensor is;

5. The image sensor of claim 4 wherein three adjacent minimal repeating units are arranged as follows:

6. The image sensor of claim 4 wherein five adjacent minimal repeating units are arranged as follows:

7. The image sensor of claim 4 wherein each of the at least three minimal repeating units is adjacent to at least two of the remaining minimal repeating units.

8. The image sensor of claim 4 wherein the combining means includes combining pixels of like color from four adjacent minimal repeating units that are arranged linearly.

9. The image sensor of claim 8 wherein the combining means includes combining all similarly positioned pixels from the first group from the middle two minimal repeating units together with some similarly positioned pixels from the first group from the remaining two minimal repeating units.

10. The image sensor of claim 9 wherein the minimal repeating units of the image sensor are arranged linearly in overlapping groups of four such that the leftmost minimal repeating unit of a group of four serves as the rightmost minimal repeating unit of another group of four, and the rightmost minimal repeating unit of a group of four serves as the leftmost minimal repeating unit of yet another group of four.

11. The image sensor of claim 8 wherein the four adjacent minimal repeating units are arranged as follows:

12. The image sensor of claim 4 wherein pixels are combined by binning the charge from the pixels, by averaging the voltages produced by the pixels, or by first converting the pixel values to digital numbers and then combining the digital numbers, or combinations thereof.

13. The image sensor of claim 12 wherein the voltages are averaged by first charging capacitors to the voltages produced by the pixels and then connecting the capacitors together to average the voltages, with the capacitors being of equal sizes to perform a simple average or of differing sizes to perform a weighted average.

14. An image sensor for capturing a color image, comprising:

a) a two-dimensional array having first and second groups of pixels, arranged in rows and columns, 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 pixels that have spectral photoresponses that correspond to a set of at least two colors;

b) the placement of the first and second groups of pixels defining a pattern that has a minimal repeating unit including at least six pixels, so that at least some rows or columns of the minimal repeating unit are composed only of pixels from the second group,

c) means for combining similarly positioned pixels from at least two adjacent minimal repeating units, and

d) wherein the minimal repeating unit of the image sensor is;

15. The image sensor of claim 14 wherein pixels are combined by binning the charge from the pixels, by averaging the voltages produced by the pixels, or by first converting the pixel values to digital numbers and then combining the digital numbers, or combinations thereof.

16. The image sensor of claim 15 wherein the voltages are averaged by first charging capacitors to the voltages produced by the pixels and then connecting the capacitors together to average the voltages, with the capacitors being of equal sizes to perform a simple average or of differing sizes to perform a weighted average.

17. An image sensor for capturing a color image, comprising:

a) a two-dimensional array having first and second groups of pixels, arranged in rows and columns, 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 pixels that have spectral photoresponses that correspond to a set of at least two colors;

b) the placement of the first and second groups of pixels defining a pattern that has a minimal repeating unit including at least six pixels, so that at least some rows or columns of the minimal repeating unit are composed only of pixels from the second group,

c) means for combining pixels of like color from at least three adjacent minimal repeating units, and

d) wherein the minimal repeating unit of the image sensor is;

18. The image sensor of claim 17 wherein three adjacent minimal repeating units are arranged as follows:

19. The image sensor of claim 17 wherein each of the at least three minimal repeating units is adjacent to at least two of the remaining minimal repeating units.

20. The image sensor of claim 17 wherein the combining means includes combining pixels of like color from four adjacent minimal repeating units that are arranged linearly.

21. The image sensor of claim 20 wherein four adjacent minimal repeating units are arranged as follows:

22. The image sensor of claim 20 wherein the combining means includes combining all similarly positioned pixels from the first group from the middle two minimal repeating units together with some similarly positioned pixels from the first group from the remaining two minimal repeating units.

23. The image sensor of claim 22 wherein the minimal repeating units of the image sensor are arranged linearly in overlapping groups of four such that the leftmost minimal repeating unit of a group of four serves as the rightmost minimal repeating unit of another group of four, and the rightmost minimal repeating unit of a group of four serves as the leftmost minimal repeating unit of yet another group of four.

24. The image sensor of claim 17 wherein pixels are combined by binning the charge from the pixels, by averaging the voltages produced by the pixels, or by first converting the pixel values to digital numbers and then combining the digital numbers, or combinations thereof.

25. The image sensor of claim 24 wherein the voltages are averaged by first charging capacitors to the voltages produced by the pixels and then connecting the capacitors together to average the voltages, with the capacitors being of equal sizes to perform a simple average or of differing sizes to perform a weighted average.