Active pixel color linear sensor with line—packed pixel readout

• US 6,388,241 B1
• Filed: 02/18/1999
• Issued: 05/14/2002
• Est. Priority Date: 02/19/1998
• Status: Expired due to Term

• Current Assignee: Aptina Imaging Corporation (ON Semiconductor Corporation)
• Original Assignee: Photobit Corporation (Micron Technology, Inc.)
• Inventors: Ang, Lin Ping
• Primary Examiner(s): EVANS, FANNIE L
• Application Number:
  US09/252,428
• Time in Patent Office: 1,181 Days
• Field of Search: 250/208.1, 348/266, 348/272, 348/273, 348/275, 348/280, 348/281, 348/302, 348/303, 348/308
• US Class Current: 250/208.1
• CPC Class Codes: H04N 25/701 Line sensors

Abstract

A CMOS active pixel color linear image sensor is operable in line-packed readout mode, and at very high speed. In accordance with a preferred embodiment, the sensor is formed entirely on a single-chip and may be further configurable for operation in parallel-packed and/or pixel-packed modes. Line-packed pixel readout is accomplished by spreading same color pixel signal sampled values in storage elements across each of plural readout register arrays in a “cyclic” manner. Facility is introduced for starting the reading of a next pixel (e.g., R pixel 2) even before the previous pixel (R pixel 1) has been read out to increase the effective pixel readout rate.

Claims

1. A color linear active pixel image sensor operable in line-packed pixel readout mode, comprising:

a focal plane array of m×

n pixels defined by at least a first, second and third linear arrays of predetermined color pixels; and

a line control/readout logic circuit sampling the m×

n pixels and reading them out to associated (m×

n) storage elements which cooperatively define at least a first, second and third readout register array coupled to said first, second and third linear arrays, the logic circuit further comprising line store select logic for storing and then reading out the pixels, during line-packed pixel readout mode, in a cyclic manner across the first, second and third readout register arrays.

2. The sensor of claim 1, wherein the line control/readout logic circuit includes means for selecting the line-packed pixel readout mode.

3. The sensor of claim 2, wherein the sensor is further operable in at least one of a parallel-packed and pixel-packed modes.

4. The sensor of claim 3, wherein the three linear arrays are comprised of a red, green and blue linear arrays, respectively.

5. The sensor of claim 4, wherein each of the linear arrays is a two-row linear array with pixels in different rows being spaced a half pitch apart in the lateral direction.

6. The sensor of claim 5, wherein the sensor is on a single chip.

7. The sensor of claim 6, further comprising means for reading out a subsequent pixel stored in a different register array than a preceding pixel, at a predetermined interval after the preceding pixel readout has begun but before the interval has lapsed.

8. The sensor of claim 1, wherein the sensor is on a single chip and further operable in at least one of a parallel-packed and pixel-packed modes, the sensor further comprising means for selecting amongst the line-packed, parallel-packed, and pixel-packed available modes.

9. The sensor of claim 1, wherein each of the linear arrays is a two-row linear array with pixels in different rows being spaced a half pitch apart in the lateral direction.

10. The sensor of claim 9, wherein each of the readout register arrays is a two-row linear array.

11. The sensor of claim 1, further comprising means for reading out a subsequent pixel stored in a different register array than a preceding pixel, at a predetermined interval after said preceding pixel readout has begun but before said interval has lapsed.

12. The sensor of claim 11, wherein said sensor is on a single chip.

13. In a color linear active pixel image sensor, a method of sampling and storing pixel elements to be read out in line-packed form comprising:

sampling and storing a first pixel of a first color linear array in a storage element of a first readout register array;

sampling and storing a first subsequent pixel of the first color linear array in a storage element of a second readout register array;

sampling and storing a second subsequent pixel of the first color linear array in a storage element of a third readout register array; and

repeating the sampling and storing for all successive subsequent pixels of the first color linear array in cyclic manner in predefined storage elements in the first, second and third register arrays.

14. The method of claim 13, wherein said sensor is operable in one of parallel-packed, pixel-packed, and line-packed readout modes, the method further comprising:

switching from the line-packed readout mode to the parallely-packed form or the pixel-packed form; and

after switching;

sampling and storing all pixels associated with the first color linear array in the first readout register array;

sampling and storing all pixels associated with a second color linear array in the second readout register array; and

sampling and storing all pixels associated with a third color linear array in the third readout register array.

15. The method of claim 14, wherein the first, second and third color linear arrays define a focal plane array of (m×

n) pixel circuits.

16. The method of claim 15, wherein each linear array is a two-row linear array of m/2 pixel circuits, the respective rows defining two rows of the (m×

n) pixel circuits, n being equal to 2.

17. The method of claim 16, wherein each said respective row is spaced a half pitch apart in the lateral direction relative to the other said respective row.

18. The method of claim 17, wherein each readout register array is also a two row array of m/2 pixels cooperatively defining a readout register comprised of (m×

n) storage elements.

19. In a color linear active pixel image sensor, a method of reading out pixel elements in line-packed readout mode comprising:

reading out a first pixel of a first color linear array stored in a storage element of a first readout register array;

reading out a first subsequent pixel of the first color linear array stored in a storage element of a second readout register array;

reading out a second subsequent pixel of the first color linear array stored in a storage element of a third readout register array; and

repeating the above reading out steps, in cyclic manner, until all successive subsequent pixels of the first color linear array are read out from corresponding storage elements in the first, second and third readout register arrays.

20. The method of claim 19, wherein the steps of reading out any subsequent pixel starts before the interval for reading out the previous pixel is ended.