Image sensor and electronic device having the same

• US 10,379,317 B2
• Filed: 11/16/2016
• Issued: 08/13/2019
• Est. Priority Date: 11/16/2015
• Status: Active Grant

• Current Assignee: Samsung Electronics Co. Ltd.
• Original Assignee: Samsung Electronics Co. Ltd.
• Inventors: Shimokawa, Shuichi, Lee, Sangmin
• Primary Examiner(s): Tran, Sinh
• Assistant Examiner(s): Wu, Zhenzhen
• Application Number:
  US15/353,692
• Publication Number:
  US 20170142325A1
• Time in Patent Office: 1,000 Days
• Field of Search: 348294, 348345, 348349
• CPC Class Codes: G02B 7/28 Systems for automatic generation of focusing signals
• CPC Class Codes: H01L 27/14603 Special geometry or disposition of pixel-elements, address-lines or gate-electrodes
• CPC Class Codes: H01L 27/14612 involving a transistor
• 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 23/672 based on the phase difference signals
• CPC Class Codes: H04N 25/46 by combining or binning pixels
• CPC Class Codes: H04N 25/704 Pixels specially adapted for focusing, e.g. phase difference pixel sets
• CPC Class Codes: H04N 25/778 comprising amplifiers shared between a plurality of pixels, i.e. at least one part of the amplifier must be on the sensor array itself

Abstract

An image sensor according to an embodiment may include a plurality of pixels. Each pixel of the plurality of pixels may include first, second, third and fourth photodiodes configured to convert light into an electric signal, and an electric circuit configured to add at least two of the electrical signals converted respectively by the first, second, third and fourth photodiodes and then output the added signals. An electronic device according to an embodiment may include the image sensor. The image sensor and the electronic device may offer an auto focusing function by controlling signals converted by and outputted from the plurality of photodiodes. Other various embodiments are possible.

Claims

1. An electronic device comprising:

an image sensor including a plurality of pixels; and

a processor configured to control operations of the image sensor and perform an auto focusing function,

wherein each of the plurality of pixels comprises;

first, second, thirds and fourth photodiodes configured to convert light into an electrical signal, respectively; and

an electric circuit configured to;

add the electrical signals converted respectively by the first, second, third, and fourth photodiodes to generate added signals, and

output the added signals,

wherein the electric circuit includes;

a plurality of floating diffusion regions configured to;

 

using at least one floating diffusion capacitor, add a first two electrical signals in a first direction among the electrical signals converted respectively by the first, second, third, and fourth photodiodes to generate a first added signal,

 

using at least another floating diffusion capacitor, add a second two electrical signals in the first direction among the electrical signals converted respectively by the first, second, third, and fourth photodiodes to generate a second added signal,

 

using the at least one floating diffusion capacitor, add a third two electrical signals in a second direction different from the first direction among the electrical signals converted respectively by the first, second, third, and fourth photodiodes to generate a third added signal,

 

using the at least another floating diffusion capacitor, add a fourth two electrical signals in the second direction among the electrical signals converted respectively by the first, second, third, and fourth photodiodes to generate a fourth added signal, and

 

output the first, second, third, and fourth added signals; and

a plurality of transfer gates configured to selectively electrically connect the photodiodes and the plurality of floating diffusion regions,

wherein the processor outputs at least one control signal for controlling the plurality of transfer gates, and

wherein the processor is further configured to;

compare the first added signal and the second added signal to detect a phase difference in the first direction,

compare the third added signal and the fourth added signal to detect a phase difference in the second direction, and

perform the auto focusing function based on the phase differences in the first and second directions.

2. The electronic device of claim 1, wherein the first, second, third, and fourth photodiodes are disposed respectively at upper left, upper right, lower left, and lower right positions of the image sensor and are arranged in a grid form.

3. The electronic device of claim 1, wherein the plurality of floating diffusion regions includes:

a first floating diffusion region configured to;

add the electrical signals received from the first or third photodiode to generate the first added signal; and

output the first added signal; and

a second floating diffusion region configured to;

add the electrical signals received from the second or fourth photodiode to generate the second added signal; and

output the second added signal,

wherein the plurality of transfer gates includes;

a first transfer gate configured to selectively electrically connect the first photodiode and the first floating diffusion region;

a second transfer gate configured to selectively electrically connect the second photodiode and the second floating diffusion region;

a third transfer gate configured to selectively electrically connect the third photodiode and the first floating diffusion region;

a fourth transfer gate configured to selectively electrically connect the fourth photodiode and the second floating diffusion region;

a fifth transfer gate configured to selectively electrically connect the first and second photodiodes; and

a sixth transfer gate configured to selectively electrically connect the third and fourth photodiodes.

4. The electronic device of claim 3, wherein the first and fourth transfer gates are electrically connected so as to be controlled by a same first control signal, wherein the second and third transfer gates are electrically connected so as to be controlled by a same second control signal, and wherein the fifth and sixth transfer gates are electrically connected so as to be controlled by a same third control signal.

5. The electronic device of claim 1, wherein the plurality of floating diffusion regions includes:

a first floating diffusion region configured to;

add the electrical signals received from the first photodiode to generate the first added signal; and

output the first added signal; and

a second floating diffusion region configured to;

add the electrical signals received from the fourth photodiode to generate the second added signal; and

output the second added signal, and

wherein the plurality of transfer gates includes;

a first transfer gate configured to selectively electrically connect the first and second photodiodes;

a second transfer gate configured to selectively electrically connect the third and fourth photodiodes;

a third transfer gate configured to selectively electrically connect the first and third photodiodes; and

a fourth transfer gate configured to selectively electrically connect the second and fourth photodiodes.

6. The electronic device of claim 5, wherein the first and second transfer gates are electrically connected so as to be controlled by a same first control signal, and wherein the third and fourth transfer gates are electrically connected so as to be controlled by a same second control signal.

7. A method of sensing images, comprising:

converting light into first, second, third, and fourth electrical signals by first, second, third, and fourth photodiodes;

selectively electrically connecting the photodiodes and a plurality of floating diffusion regions, the plurality of floating diffusion regions including a plurality of floating diffusion capacitors,

adding, by the plurality of floating diffusion regions, using at least one of the plurality of floating diffusion capacitors, a first two electrical signals in a first direction among the first, second, third, and fourth electrical signals to generate a first added signal;

adding, by the plurality of floating diffusion regions, using at least another of the plurality of floating diffusion capacitors, a second two electrical signals in the first direction among the first, second, third, and fourth electrical signals to generate a second added signal;

adding, by the plurality of floating diffusion regions, using the at least one of the plurality of floating diffusion capacitors, a third two electrical signals in a second direction different from the first direction among the first, second, third, and fourth electrical signals to generate a third added signal;

adding, by the plurality of floating diffusion regions, using the at least another of the plurality of floating diffusion capacitors, a fourth two electrical signals in the second direction among the first, second, third, and fourth electrical signals to generate a fourth added signal;

outputting, by the plurality of floating diffusion regions, the first, second, third, and fourth added signals;

comparing, by a processor, the first added signal and the second added signal to detect a phase difference in the first direction;

comparing, by the processor, the third added signal and the fourth added signal to detect a phase difference in the second direction; and

performing, by the processor, an auto focusing function based on the phase differences in the first and second directions.

8. The method of claim 7, wherein the selectively electrically connecting is performed with a plurality of transfer gates.

9. The method of claim 8, further comprising:

controlling first and second transfer gates of the plurality of transfer gates with a same first control signal; and

controlling third and fourth transfer gates of the plurality of transfer gates with a same second control signal.

10. The method of claim 8, further comprising:

controlling first and fourth transfer gates of the plurality of transfer gates with a same first control signal;

controlling second and third transfer gates of the plurality of transfer gates with a same second control signal; and

controlling fifth and sixth transfer gates of the plurality of transfer gates with a same third control signal.