Image sensor with fixed potential output transistor
First Claim
1. An image sensor including a pixel array, the image sensor comprising:
- a first photosensitive region of a first pixel disposed in or on a substrate layer to accumulate an image charge in response to light incident upon the first pixel; and
first pixel circuitry of the first pixel disposed in or on the substrate layer, the first pixel circuitry including;
a first transfer-storage transistor coupled between the first photosensitive region and a first charge-storage area to transfer the image charge from the first photosensitive region to the first charge-storage area; and
a first output transistor having a channel coupled between the first charge-storage area and a floating diffusion region to selectively transfer the image charge from the first charge-storage area to the floating diffusion region, wherein a gate of the first output transistor is coupled to a first fixed voltage potential and the image charge is selectively transferred from the first charge-storage area to the floating diffusion region in response to a control signal applied to a gate of the first transfer-storage transistor, wherein the first output transistor is a junction gate field-effect transistor.
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Accused Products
Abstract
An image sensor pixel includes a photosensitive region and pixel circuitry. The photosensitive region accumulates an image charge in response to light incident upon the image sensor. The pixel circuitry includes a transfer-storage transistor, a charge-storage area, an output transistor, and a floating diffusion region. The transfer-storage transistor is coupled between the photosensitive region and the charge-storage area. The output transistor has a channel coupled between the charge-storage area and the floating diffusion region and has a gate tied to a fixed voltage potential. The transfer-storage transistor causes the image charge to transfer from the photosensitive region to the charge-storage area and to transfer from the charge-storage area to the floating diffusion region.
40 Citations
18 Claims
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1. An image sensor including a pixel array, the image sensor comprising:
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a first photosensitive region of a first pixel disposed in or on a substrate layer to accumulate an image charge in response to light incident upon the first pixel; and first pixel circuitry of the first pixel disposed in or on the substrate layer, the first pixel circuitry including; a first transfer-storage transistor coupled between the first photosensitive region and a first charge-storage area to transfer the image charge from the first photosensitive region to the first charge-storage area; and a first output transistor having a channel coupled between the first charge-storage area and a floating diffusion region to selectively transfer the image charge from the first charge-storage area to the floating diffusion region, wherein a gate of the first output transistor is coupled to a first fixed voltage potential and the image charge is selectively transferred from the first charge-storage area to the floating diffusion region in response to a control signal applied to a gate of the first transfer-storage transistor, wherein the first output transistor is a junction gate field-effect transistor. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. An image sensor including a pixel array, the image sensor comprising:
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a first photosensitive region of a first pixel disposed in or on a substrate layer to accumulate an image charge in response to light incident upon the first pixel; and first pixel circuitry of the first pixel disposed in or on the substrate layer, the first pixel circuitry including; a first transfer-storage transistor coupled between the first photosensitive region and a first charge-storage area to transfer the image charge from the first photosensitive region to the first charge-storage area; and a first output transistor having a channel coupled between the first charge-storage area and a floating diffusion region to selectively transfer the image charge from the first charge-storage area to the floating diffusion region, wherein a gate of the first output transistor is coupled to a first fixed voltage potential and the image charge is selectively transferred from the first charge-storage area to the floating diffusion region in response to a control signal applied to a gate of the first transfer-storage transistor, wherein; the first transfer-storage transistor is coupled to transfer the image charge from the first photosensitive region to the first charge-storage area in response to a first voltage level of the control signal, the first transfer-storage transistor is coupled to store the image charge in the first charge-storage area in response to a second voltage level of the control signal, the first transfer-storage transistor is coupled to transfer the image charge from the first charge-storage area to the floating diffusion region in response to a third voltage level of the control signal, and the second voltage level is between the first and third voltage levels of the control signal.
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11. A method of operating an image sensor, comprising:
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accumulating a first image charge on a first photosensitive region of a first pixel in response to light incident upon the first photosensitive region; transferring the first image charge from the first photosensitive region to a first charge-storage area by temporarily enabling a first transfer-storage transistor coupled between the first photosensitive region and the first charge-storage area; storing the first image charge in the first charge-storage area; temporarily enabling a first output transistor having a gate coupled to a first fixed voltage potential by applying a first control signal to a gate of the first transfer-storage transistor; transferring the first image charge from the first charge-storage area to a floating diffusion region through the first output transistor while the first control signal is applied to the gate of the first transfer-storage transistor, wherein the first output transistor is coupled between the first charge-storage area and the floating diffusion region; enabling the first transfer-storage transistor by applying a first voltage level of the first control signal to the first transfer-storage transistor; storing the first image charge in the first charge-storage area by applying a second voltage level of the first control signal to the first transfer-storage transistor; and enabling the first output transistor by applying a third voltage level of the first control signal to the first transfer-storage transistor, wherein the second voltage level is between the first and third voltage levels. - View Dependent Claims (12, 13, 14, 15, 16, 17)
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18. An image sensor including a pixel array, the image sensor comprising:
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a first photosensitive region of a first pixel disposed in or on a substrate layer to accumulate an image charge in response to light incident upon the first pixel; first pixel circuitry of the first pixel disposed in or on the substrate layer, the first pixel circuitry including; a first transfer-storage transistor coupled between the first photosensitive region and a first charge-storage area to transfer the image charge from the first photosensitive region to the first charge-storage area; and a first output transistor having a channel coupled between the first charge-storage area and a floating diffusion region to selectively transfer the image charge from the first charge-storage area to the floating diffusion region, wherein a gate of the first output transistor is coupled to a first fixed voltage potential and the image charge is selectively transferred from the first charge-storage area to the floating diffusion region in response to a control signal applied to a gate of the first transfer-storage transistor; a second pixel disposed adjacent to the first pixel including a second photosensitive region and second pixel circuitry of the second pixel disposed in or on the substrate layer, the second pixel circuitry including; a second transfer-storage transistor coupled between the second photosensitive region and a second charge-storage area; and a second output transistor having a channel coupled between the second charge-storage area and the floating diffusion region, wherein a gate of the second output transistor is coupled to a second fixed voltage potential, wherein the first and second pixel share the readout and reset transistors; a local interconnect that couples the first output transistor to the second output transistor, wherein the local interconnect is coupled to the floating diffusion region; and a metal stack to route signals, wherein the metal stack includes; a first metal layer comprised of conductors, wherein the majority of the conductors are substantially parallel to one another; and a second metal layer comprised of conductors, wherein the majority of the conductors are both substantially parallel to one another within the second metal layer and substantially orthogonal to the majority of the conductors in the first metal layer, wherein the local interconnect is disposed in the metal stack such that the local interconnect is substantially orthogonal to the majority of the conductors in the metal layer in which the local interconnect is disposed.
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Specification