Image sensor with controllable transfer gate off state voltage levels
First Claim
1. An image sensor comprising:
- a pixel array comprising a plurality of pixels each having a photosensitive element coupled to a transfer gate; and
a signal generator coupled to the pixel array;
wherein the signal generator is configured to generate a transfer gate signal for application to at least one of the transfer gates; and
wherein the transfer gate signal has at least an on state voltage level and first and second off state voltage levels, wherein the first off state voltage level has a higher magnitude than that of the second off state voltage level, and wherein the transfer gate signal has the second off state voltage level during readout of one or more of the pixels.
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Accused Products
Abstract
A CMOS image sensor or other type of image sensor comprises a pixel array and a signal generator coupled to the pixel array. The pixel array comprises a plurality of pixels each having a photosensitive element coupled to a transfer gate. The signal generator is configured to generate a transfer gate signal for application to at least one of the transfer gates. The transfer gate signal has at least an on state voltage level and first and second off state voltage levels, with the first off state voltage level typically having a higher magnitude than that of the second off state voltage level. In an illustrative embodiment, the second off state voltage level is utilized during a readout operation in order to reduce dark current in floating diffusion regions of the pixel array.
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Citations
19 Claims
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1. An image sensor comprising:
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a pixel array comprising a plurality of pixels each having a photosensitive element coupled to a transfer gate; and a signal generator coupled to the pixel array; wherein the signal generator is configured to generate a transfer gate signal for application to at least one of the transfer gates; and wherein the transfer gate signal has at least an on state voltage level and first and second off state voltage levels, wherein the first off state voltage level has a higher magnitude than that of the second off state voltage level, and wherein the transfer gate signal has the second off state voltage level during readout of one or more of the pixels. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13)
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14. A method for use in an image sensor comprising a pixel array having a plurality of pixels each with a photosensitive element coupled to a transfer gate, the method comprising the step of:
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generating a transfer gate signal for application to at least one of the transfer gates; wherein the transfer gate signal has at least an on state voltage level and first and second off state voltage levels, the first off state voltage level having a higher magnitude than that of the second off state voltage level, and reading out one or more of the pixels while the transfer gate signal has the second off state voltage level. - View Dependent Claims (15, 16)
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17. A digital imaging device comprising:
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an image sensor; and one or more processing elements configured to process outputs of the image sensor to generate a digital image; wherein said image sensor comprises; a pixel array comprising a plurality of pixels each having a photosensitive element coupled to a transfer gate; and a signal generator coupled to the pixel array; wherein the signal generator is configured to generate a transfer gate signal for application to at least one of the transfer gates; and wherein the transfer gate signal has at least an on state voltage level and first and second off state voltage levels, wherein the first off state voltage level has a higher magnitude than that of the second off state voltage level, and wherein the transfer gate signal has the second off state voltage level during readout of one or more of the pixels. - View Dependent Claims (18, 19)
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Specification