Active pixel sensor with programmable color balance

• US 6,714,239 B2
• Filed: 10/29/1997
• Issued: 03/30/2004
• Est. Priority Date: 10/29/1997
• Status: Expired due to Term

• Current Assignee: Omnivision Technologies Incorporated (Will Semiconductor Co., Ltd. Shanghai)
• Original Assignee: Eastman Kodak Company
• Inventors: Guidash, Robert M.
• Primary Examiner(s): Moe, Aung
• Assistant Examiner(s): NGUYEN, LUONG TRUNG
• Application Number:
  US08/960,418
• Publication Number:
  US 20020180875A1
• Time in Patent Office: 2,344 Days
• Field of Search: 348/223, 348/296, 348/297, 348/304, 348/308, 348/280, 348/281, 348/282, 348/96, 348/223.1
• US Class Current: 348/223.1
• CPC Class Codes: H01L 27/14609 Pixel-elements with integrated switching, control, storage or amplification elements scanning details of imagers (circuitry of solid-state image sensors H04N25/00); circuitry of imagers H04N25/70
• CPC Class Codes: H01L 27/14645 Colour imagers
• CPC Class Codes: H04N 25/534 depending on the spectral component

Abstract

A semiconductor based image sensor comprising a plurality of pixels formed upon a major surface of a semiconductor substrate, a majority of the pixels having a photodetector with a plurality of color filters of at least two different colors arranged over a second majority of the pixels a sense node formed within each of the pixels and operatively connected to CMOS control circuitry a plurality of busses arranged such that there is at least one unique bus operatively connected to the pixels for each color and interface means for providing an electrical connection to a timing circuit, the interface means having individual connections to each of the busses and capable of providing the predetermined voltage on the busses at a desired time.

Claims

1. A semiconductor based, active pixel image sensor comprising:

an active pixel sensor comprising;

a plurality of active pixels formed upon a major surface of a semiconductor substrate, a plurality of the pixels having a photodetector which plurality of pixels are arranged in a plurality of columns and rows for forming a two dimensional array;

wherein the active pixels convert a charge packet to voltage signal;

a plurality of color filters of at least two different colors arranged over a majority of the pixels for forming colored pixels which are arranged with at least two different colored pixels in a single row;

a plurality of transfer gates, the transfer gates being adjacent to the photodetectors and controlled by one of a plurality of electrodes, the transfer gates being capable of modulating the electrostatic potential adjacent to the photodetector upon application of a predetermined voltage to the electrode for that transfer gate to remove charge from the photodetector;

at least two buses per row arranged such that there is at least one bus for each color of the different colors in the row, each of the buses being operatively connected to the transfer gates associated with only one of the different colors through one of the electrodes;

wherein all signals from pixels in a single row are read out substantially simultaneously to their corresponding buses;

interface means for providing an electrical connection to a timing circuit, the interface means having at least one connection to each of the color buses and at least one input from the timing circuit for each connection;

whereby each of the different colors can have an integration period that is controlled by the timing circuit independent from other of the different colors, and the integration time of substantially all colors in the entire two dimensional array ends substantially simultaneously.

2. The image sensor of claim 1 wherein the plurality of pixels are arranged in rows and columns.

3. The image sensors of claim 2 wherein the image sensor has three colors with only two colors in any given row and with row adjacent pixels not being of the same color.

4. The image sensor of claim 1 wherein the sensor is an active pixel sensor having CMOS control circuitry allocated for, essentially, each of the pixels.

5. The image sensor of claim 4 wherein each of the transfer gates have a floating diffusion area as the sense node that is connected as an input to a signal transistor, the signal transistor formed in CMOS.

6. The image sensor of claim 1 wherein the sensor is a multiple color linear sensor having at least two linear sensor channels with each of the sensor channels sensitive to light of a different wavelength.

7. The image sensor of claim 6 wherein the sensor is a tri-linear sensor having separately controllable integration times for each of the linear sensors channels determined by voltages on their respective transfer gates which are controlled through a timing circuit.

8. The image sensor of claim 1 further comprising a reset gate adjacent to the sense node, the reset gate being electrically connected to a bus on at least a row by row basis.

9. The image sensor of claim 8 wherein the integration period is controlled by pulsing the transfer gates and reset gates.

10. A semiconductor based, active pixel image sensor comprising:

an active pixel sensor comprising;

a plurality of active pixels formed upon a major surface of a semiconductor substrate, a plurality of the pixels each having a photodetector which plurality of pixels are arranged in a plurality of columns and rows for forming a two dimensional array;

wherein the active pixels convert a charge packet to voltage signal;

a plurality of color filters of at least two different colors arranged over a majority of the pixels for forming colored pixels which arranged with at least two different colored pixels in a single row;

a plurality of gates adjacent to the photodetectors and controlled by one of a plurality of electrodes, the gates being capable of draining charge from the photodetector upon application of a predetermined voltage to the electrode for that gate;

a sense node formed within the pixel and operatively connected to CMOS control circuitry;

at least two buses per row arranged such that there is at least one bus for each color of the color filters in the row, each of the buses being operatively connected to the gates associated with only one of the colors through one of the electrodes;

wherein all signals from pixels in a single row are read out substantially simultaneously to their corresponding buses;

interface means for providing an electrical connection to a timing circuit, the interface means having individual connections to each of the buses and capable of providing the predetermined voltage on the buses at a desired time;

whereby each color can have an integration period that is controlled by the timing circuit independent from an equivalent integration for the other colors, and the integration time of substantially all colors in the entire two dimensional array ends substantially simultaneously.

11. The image sensor of claim 10 wherein the gates are reset gates.

12. The image sensor of claim 10 wherein the plurality of pixels are arranged in rows and columns.

13. The image sensors of claim 10 wherein the image sensor has three colors with only two colors in any given row and with row adjacent pixels not being of the same color.

14. The image sensor of claim 10 wherein the photodetector has a pinned portion and an unpinned portion and the sense node is formed on the unpinned portion.

15. The image sensor of claim 10 wherein the sense node is operatively connected to CMOS control circuitry as an input to a transistor.

16. The image sensor of claim 10 wherein the sensor has a plurality of linear sensors, with at least two colors being represented on the linear sensors.

17. The image sensor of claim 16 wherein the plurality of linear sensors further comprises a separate linear sensor for each different color.

18. The image sensor of claim 17 wherein each of the separate image sensors has a single bus to control integration time.

19. The image sensor of claim 10 further comprising a transfer gate between the photodetector and the sense node.

20. A semiconductor based, active pixel image sensor comprising:

an active pixel sensor comprising;

a plurality of active pixels formed upon a major surface of a semiconductor substrate, a majority of the pixels having a photodetector which pixels are arranged in a plurality of columns and rows for forming a two dimensional array;

wherein the active pixels convert a charge packet to a voltage signal;

a plurality of color filters of at least two different colors arranged over a second majority of the pixels for forming colored pixels which are arranged with at least two different colored pixels in a single row;

a sense node formed within each of the pixels and operatively connected to CMOS control circuitry;

at least two buses per row arranged such that there is at least one unique bus operatively connected to the pixels for each color in the row;

wherein all signals from pixels in a single row are read out substantially simultaneously to their corresponding buses; and

interface means for providing an electrical connection to a timing circuit, the interface means having individual connections to each of the buses and capable of providing the predetermined voltage on the buses at a desired time;

whereby each color can have an integration period that is controlled by the timing circuit independent from an equivalent integration for the other colors, and the integration time of substantially all colors in the entire two dimensional array ends substantially simultaneously.

21. The invention of claim 20 wherein the photodetector in a photogate.

22. The invention of claim 21 wherein the busses are connected to the photogates.

23. The invention of claim 22 wherein the busses connected to the photogates are operative to control integration timing of the photogates.

24. The invention of claim 21 further comprising a reset gate within each pixel.

25. The invention of claim 21 further comprising a transfer gate and a sense node within each pixel.

26. The invention of claim 20 wherein the integration periods for colors having shorter integration time are contained within the integration periods of colors having longer integration periods.

27. The invention of claim 25 wherein integration periods for each color are centered with respect to the integration periods of other colors.