Claims
- 1. An image sensing device comprising:
- an array of photodetectors capable of generating electron/hole pairs from incident photons;
- a first charge coupled device having a plurality of cells, the first charge coupled device being operatively coupled to the photodetectors by first transfer means for placing charge accumulated within the photodetectors from generated electron/hole pairs within the first charge coupled device;
- a second charge coupled device having a plurality of cells being operatively coupled to the first charge coupled device by second transfer means for removing charge exceeding a threshold within the first charge coupled device and placing charge exceeding the threshold within the second charge coupled device;
- clocking means for cycling charge through the cells of the first and second charge coupled devices;
- first output means for receiving transferred charge from the first charge coupled device;
- second output means for receiving transferred charge from the second charge coupled device; and
- combinatorial means for creating a combined output based on the first output means and the second output means.
- 2. The invention of claim 1 wherein one of the charge coupled devices is larger than the other.
- 3. The invention of claim 1 further comprising means for altering the charge storage capacity of the charge coupled devices.
- 4. The invention of claim 1 further comprising at least a third charge coupled device being operatively coupled to one of the previous charge coupled device and having means for transferring charge exceeding a threshold from the previous charge coupled device, the third charge coupled device also being coupled to third output means for receiving transferred charge from the third charge coupled device, the third output means being operatively coupled to combinatorial means for generating a predetermined output based on the first, second and third output means.
- 5. The invention of claim 1 wherein the output means further comprises means for digitizing charges contained within the charge coupled devices and combining the digitized signals into at least one signal representative of charge contained within the charge coupled devices.
- 6. The invention of claim 1 wherein the output means further comprises analog means for combining analog signals generated from output amplifiers into at least one signal representative of charge contained within the charge coupled devices.
- 7. The invention of claim 1 wherein the image sensing device is a linear image sensor.
- 8. The invention of claim 1 wherein the image sensing device is an area image sensor.
- 9. The image sensing device of claim 1 further comprising overflow drain means for controlling excess charge from spilling to other pixels.
- 10. The image sensing device of claim 1 wherein the image sensing device is employed in a digital camera.
- 11. The image sensing device of claim 1 wherein the image sensing device is employed in a film scanner.
- 12. A method of creating an image sensing device comprising the steps of:
- providing as a sensor an array of photodetectors capable of generating electron/hole pairs from incident photons coupled to an adjacent first charge coupled device having a plurality of cells operatively coupled to transfer means for placing charge from the photodetectors into the first charge coupled device;
- additionally providing a second charge coupled device with second transfer means such that charge exceeding a threshold within the first charge coupled device will flow into the second charge coupled device;
- organizing the first charge coupled device such that cells with the first charge coupled device are serially shifted to adjacent cells within the first charge coupled device in bucket brigade fashion;
- organizing the second charge coupled device such that cells with the second charge coupled device are serially shifted to adjacent cells within the second charge coupled device in bucket brigade fashion;
- providing clocking means for cycling charge through cells of the first and second charge coupled devices to output means; and
- providing output means for combining charges from the first charge coupled device and the second charge coupled device such that an output is generated for each of the photodetectors that is a combination of at least one cell in the first charge coupled device and at least one cell in the second charge coupled device.
- 13. The method of claim 12 wherein the step of additionally providing the second charge coupled device further comprises providing second cells within the second charge coupled device that have larger charge storage capacity than the cells within the first charge coupled device.
- 14. The method of claim 12 wherein the step of additionally providing further comprises providing means for altering the charge storage capacity of wells within at least one of the charge coupled devices.
- 15. The method of claim 12 further comprising at least a third charge coupled device operatively coupled to one of the previous charge coupled device and having means for transferring charge exceeding a threshold from the previous charge coupled device, the third charge coupled device also being coupled to output means.
- 16. The method of claim 12 wherein the creating step further comprises creating output means having means for digitizing charges contained within the charge coupled devices and combining the digitized signals into at least one signal.
- 17. The method of claim 12 wherein the creating step further comprises creating analog output means for combining analog signals generated from output amplifiers into at least one signal.
- 18. The method of claim 12 wherein the providing step further comprises as the sensor a linear image sensor.
- 19. The method of claim 12 wherein the providing step further comprises providing the sensor that is an area image sensor.
- 20. The method of claim 12 wherein the providing step further comprises providing an overflow drain means.
- 21. In an active pixel image sensor having at least one photodetector capable of generating electron/hole pairs in response to incident light, original storage well means for accumulating charge from the photodetector and means for removing the charge from the storage well means to processing circuitry, the improvement comprising additional storage wells such that the original storage well means and the additional storage wells are organized to provide multiple stages of cascading storage wells, the additional storage wells storing charge from adjacent storage wells within the original storage well means closer to the photodetector that exceeds a threshold limit existing on cells within the original storage well means, with means for removing charge from the original storage well means and the adjacent storage wells being coupled to each of the original storage well means and adjacent storage wells such that charge can be removed independently from each the original storage well means and the adjacent storage wells independently each other, and output means for combining charges from the original storage well means and the additional storage wells into an output for the photodetector.
Parent Case Info
This is a continuation of application Ser. No. 08/419,881, filed 11 Apr. 1995, now abandoned.
US Referenced Citations (15)
Non-Patent Literature Citations (1)
Entry |
"CMOS Active Pixel Image Sensor" by Mendis, et al, IEEE Transactions on Electron Devices, vol. 41, No. 3, Mar. 1994. |
Continuations (1)
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Number |
Date |
Country |
Parent |
419881 |
Apr 1995 |
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