Image sensor including a pixel array each pixel comprising a variable capacitor and a capacitor

• US 9,287,304 B2
• Filed: 04/29/2011
• Issued: 03/15/2016
• Est. Priority Date: 04/13/2011
• Status: Active Grant

• Current Assignee: LG Innotek Company Limited (LG Corporation)
• Original Assignee: LG Innotek Company Limited (LG Corporation)
• Inventors: Park, Seong Hyung, Choi, Woon Il, Sa, Seung Hoon, Park, Cheong Yong, Lee, Dong Gyu, Ji, Hyun Jong
• Primary Examiner(s): Le, Que T
• Assistant Examiner(s): BENNETT, JENNIFER D
• Application Number:
  US13/098,030
• Publication Number:
  US 20120261549A1
• Time in Patent Office: 1,782 Days
• Field of Search: 250/208.1, 250/214.R, 250/214.1, 250/214.SW, 348/294, 348/297, 348/302, 348/303, 348/304, 348/308, 348/311, 348/314, 257/257, 257/258, 257/290, 257/291, 257/292
• US Class Current: 1/1
• 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 27/14641 Electronic components shared by two or more pixel-elements, e.g. one amplifier shared by two pixel elements
• 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

Abstract

Provided are a pixel, a pixel array, and an image sensor including the pixel array. The pixel includes a photoelectric converter, a capacitor, a variable capacitor, and a switching element. The capacitor accumulates electric charges converted by the photoelectric converter. The variable capacitor is connected to the capacitor, and has capacitance varied according to a potential of the capacitor. The switching element outputs the potential of the capacitor.

Claims

1. A pixel comprising:

a plurality of photoelectric converters disposed on a substrate;

a capacitor connected to the photoelectric converters, and accumulating electric charges converted by the photoelectric converters;

a variable capacitor connected to the capacitor and connected directly to the substrate, and having capacitance varied according to a potential of the capacitor; and

a switching element outputting the potential of the capacitor,

wherein the switching element comprises;

a transfer switching element provided between the photoelectric converters and the capacitor and between the photoelectric converters and the variable capacitor to transfer the electric charges converted by the photoelectric converters to the capacitor;

a reset switching element provided between a power voltage line and the capacitor to reset the potential of the capacitor; and

an output switching element connected to the power voltage line to output the potential of the capacitor, and

wherein the capacitor and the variable capacitor are connected to the output switching element.

2. The pixel according to claim 1, wherein the variable capacitor is self-biased.

3. The pixel according to claim 1, wherein the variable capacitor is a p-type variable capacitor.

4. The pixel according to claim 1, wherein the variable capacitor has one node connected to a gate of the output switching element and the capacitor, and the other node connected to the substrate connected to a ground node.

5. The pixel according to claim 1, wherein the capacitor acts as a storage through multi-clocking of the transfer switching element with the variable capacitor.

6. The pixel according to claim 1, wherein the photoelectric converters comprise a first photoelectric converter and a second photoelectric converter,

the transfer switching element comprises:

a first transfer switching element transferring first electric charges, converted in the first photoelectric converter, to the capacitor; and

a second transfer switching element transferring second electric charges, converted in the second photoelectric converter, to the capacitor, and

the first transfer switching element and the second transfer switching element are electrically shared with the capacitor and the variable capacitor.

7. The pixel according to claim 1, wherein the capacitance of the variable capacitor increases as the potential of the capacitor increases.

8. A pixel array comprising the pixel of claim 1 as an array.

9. A pixel array comprising the pixel of claim 2 as an array.

10. A pixel array comprising the pixel of claim 3 as an array.

11. A pixel array comprising the pixel of claim 4 as an array.

12. A pixel array comprising the pixel of claim 5 as an array.

13. A pixel array comprising the pixel of claim 6 as an array.

14. A pixel array comprising the pixel of claim 7 as an array.

15. An image sensor comprising the pixel array of claim 8.