HYBRID IMAGE SENSOR

• US 20140267855A1
• Filed: 03/12/2013
• Published: 09/18/2014
• Est. Priority Date: 03/12/2013
• Status: Active Grant

• Current Assignee: Apple Inc.
• Original Assignee: Apple Inc.
• Inventors: Fan, Xiaofeng
• Granted Patent: US 9,549,099 B2
• Time in Patent Office: Days
• US Class Current: 348/302
• 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 27/14806 Structural or functional details thereof
• CPC Class Codes: H04N 25/00 Circuitry of solid-state image sensors [SSIS]; Control thereof
• CPC Class Codes: H04N 25/59 by controlling the amount of charge storable in the pixel, e.g. modification of the charge conversion ratio of the floating node capacitance
• CPC Class Codes: H04N 25/616 involving a correlated sampling function, e.g. correlated double sampling [CDS] or triple sampling
• CPC Class Codes: H04N 25/75 Circuitry for providing, modifying or processing image signals from the pixel array
• CPC Class Codes: H04N 25/771 comprising storage means other than floating diffusion
• CPC Class Codes: H04N 25/78 Readout circuits for addressed sensors, e.g. output amplifiers or A/D converters
• CPC Class Codes: H04N 3/155 Control of the image-sensor operation, e.g. image processing within the image-sensor

Abstract

A method for performing correlated double sampling for a sensor, such as an image sensor. The method includes collecting a first charge corresponding to a first parameter, transferring the first charge to a first storage component, transferring the first charge from the first storage component to a second storage component, resetting the first storage component, transferring the first charge from the second storage component to the first storage component, and reading the first storage component to determine the first charge. The method may be implemented in electronic devices including image sensors.

Claims

1. An image sensor for an electronic device, comprising:

a light sensitive element configured to produce a charge corresponding to a light parameter;

a transfer gate in communication with the light sensitive element;

a floating diffusion node in communication with the light sensitive element;

a storage gate in communication with the floating diffusion node;

a reset gate in communication with the light sensitive element;

a source follower gate in communication with the storage gate; and

a row select gate in communication with the source follower gate and the storage gate; and

a logic chip operably connected to the transistor array chip and in communication therewith;

wherein

the transfer gate communicates data from the light sensitive element to floating diffusion node;

the logic chip selectively activates the transfer gate, the reset gate, the source follower gate, the row select gate, and the storage gate; and

the storage gate has a variable potential.

2. The image sensor of claim 1, wherein the transfer gate has a set potential.

3. The image sensor of claim 1, wherein the charge is transferrable from the floating diffusion node to the storage gate and from the storage gate to the floating diffusion node.

4. The image sensor of claim 1, wherein the potential of the storage gate is related to a voltage applied to the storage gate.

5. The image sensor of claim 1, wherein the light sensitive element is a photodiode.

6. A method for performing correlated double sampling for a sensor, comprising:

collecting a first charge corresponding to a first parameter;

transferring the first charge to a first storage component;

transferring the first charge from the first storage component to a second storage component;

resetting the first storage component;

transferring the first charge from the second storage component to the first storage component; and

reading the first storage component to determine the first charge.

7. The method of claim 6, wherein the sensor is an image sensor.

8. The method of claim 6, wherein the second storage component has a variable potential.

9. The method of claim 8, wherein the variable potential is determined by a voltage applied to the second storage component.

10. The method of claim 6, wherein the first storage component has a set potential.

11. The method of claim 10, wherein the set potential is determined by a characteristic of a material forming the first storage component.

12. The method of claim 6, wherein the parameter is light.

13. The method of claim 6, further comprising collecting a second charge corresponding to a second parameter.

14. The method of claim 11, further comprising

after resetting the first storage component, transferring the second charge to the first storage component;

and

reading out the first storage component to determine the first charge and the second charge.

15. The method of claim 6, wherein reading the first storage component to determine the first charge is performed by a processor.

16. An electronic device, comprising:

a display;

a processor in communication with the display; and

a camera in communication with the processor, the camera comprising;

a lens;

an image sensor in optical communication with the lens, the image sensor including a plurality of pixels, each pixel in the plurality of pixels comprising;

a photodiode configured to detect light transmitted from the lens and create a light value corresponding to the light detected;

a first transfer gate in communication with the photodiode;

a floating diffusion node in communication with the first transfer gate;

a second transfer gate in communication with the floating diffusion node;

a two-way storage component in communication with the floating diffusion node through the second transfer gate;

wherein

the first transfer gate transfers the light value from the photodiode to the floating diffusion node; and

the second gate transfers the light value from the floating diffusion node to the second transfer gate and from the second transfer gate to the floating diffusion node; and

an image processor in communication with the image sensor and the processor.

17. The electronic device of claim 16, wherein the display is configured to display an image corresponding to the light value for each pixel within the plurality of pixels.

18. The electronic device of claim 16, wherein the storage component has a charge potential determined, at least in part, by a voltage applied to an electrode positioned above the storage component.

19. The electronic device of claim 18, wherein the first transfer gate and the second transfer gate have a fixed charge potential.

20. The electronic device of claim 16, wherein the image sensor includes at least two chips.