Image sensor and imaging device including the same

Patent metadata

Field	Value
Publication number	US-11438535-B2
Application number	US-202016989227-A
Country	US
Kind code	B2
Filing date	Aug 10, 2020
Priority date	Feb 12, 2020
Publication date	Sep 6, 2022
Grant date	Sep 6, 2022

Abstract

An imaging device includes a pixel array with first and second pixels respectively having first and second conversion gains connected to row and column lines; a row driver determining a selection row line among the row lines; a readout circuit obtaining first and second pixel signals from first and second pixels connected to the selection row line; a column driver generating first and second image data from the first and second pixel signals; and an image signal processor using the first and second image data to generate an object image. The second pixels include an expansion capacitor connected between a floating diffusion node and a ground node. Exposure time of the first pixels is equal to or longer than exposure time of the second pixels. An area of a light receiving region of the first pixels is equal to an area of a light receiving region of the second pixels.

First claim

What is claimed is:

1. An imaging device comprising:
a pixel array connected to a plurality of row lines and a plurality of column lines, and including a plurality of first pixels having a first conversion gain and a plurality of second pixels having a second conversion gain lower than the first conversion gain;
a row driver configured to determine a selection row line from among the plurality of row lines;
a readout circuit configured to respectively obtain a first pixel signal and a second pixel signal from first pixels and second pixels connected to the selection row line;
a column driver configured to generate first image data from the first pixel signal and second image data from the second pixel signal; and
an image signal processor configured to generate an object image from the first image data and the second image data,
wherein each of the second pixels includes a floating diffusion node, a ground node, and an expansion capacitor connected between the floating diffusion node and the ground node,
the row driver is configured to set exposure time of the first pixels to be equal to or longer than exposure time of the second pixels,
an area of a light receiving region of each of the first pixels is equal to an area of a light receiving region of each of the second pixels,
the pixel array comprises a plurality of pixel groups respectively including two or more first pixels from among the plurality of first pixels, and one or more second pixels from among the plurality of second pixels, and the plurality of pixel groups have a predetermined color pattern, and
each of the plurality of pixel groups a number of the first pixels is greater than a number of the second pixels.

2. The imaging device of claim 1 , wherein in each of the plurality of pixel groups, each of the second pixels are disposed closer to a center of a pixel group than the first pixels.

3. The imaging device of claim 1 , wherein the first pixel signal corresponds to a total amount of charges generated by the first pixels connected to the selection row line.

4. The imaging device of claim 1 , wherein the readout circuit is configured to obtain the first pixel signal by converting pixel signals generated by the first pixels connected to the selection row line into digital signals, applying a predetermined weight to the digital signals, and summing the weighted digital signals.

5. The imaging device of claim 1 , wherein in an environment in which external illumination is low, the readout circuit is configured to interpolate the first pixel signal to obtain the second pixel signal.

6. The imaging device of claim 1 , wherein capacitance of the expansion capacitor is 1 fF or more and less than 1 pF.

7. An imaging device comprising:
a pixel array including a plurality of color pixel groups, wherein each of the plurality of color pixel groups including a plurality of first pixels and at least one second pixel;
an image data generator configured to expose the plurality of first pixels during a first exposure time to generate first image data, expose the at least one second pixel during the first exposure time to generate second image data, and sequentially expose the plurality of first pixels and the at least one second pixel during a second exposure time to generate third image data; and
an image signal processor configured to merge the first image data, the second image data, and the third image data, to generate an object image,
wherein the image data generator is configured to generate the first image data by summing pixel signals obtained from the plurality of first pixels.

8. The imaging device of claim 7 , wherein conversion gain of the plurality of first pixels is greater than conversion gain of the at least one second pixel.

9. The imaging device of claim 7 , wherein the plurality of first pixels share at least one floating diffusion node.

10. The imaging device of claim 7 , wherein the image data generator is configured to convert the pixel signals obtained by the plurality of first pixels into digital signals, apply a predetermined weight to the digital signals, and sum the weighted digital signals to generate the first image data.

11. The imaging device of claim 7 , wherein each of the plurality of color pixel groups has an N×M matrix structure, wherein N and M are positive integers.

12. The imaging device of claim 11 , wherein in each of the plurality of color pixel groups the at least one second pixel is disposed closer to a center of a color pixel group than the first pixels.

13. The imaging device of claim 12 , wherein an area of a light receiving region of each of the plurality of first pixels is equal to an area of a light receiving region of the at least one second pixel.

14. An image sensor comprising:
a plurality of first pixels including a first floating diffusion region disposed in a substrate and a plurality of first photodiodes connected to the first floating diffusion region;
at least one second pixel including a second floating diffusion region disposed in the substrate and at least one second photodiode connected to the second floating diffusion region, the second floating diffusion region is disposed adjacent to the first pixels in a direction parallel to an upper surface of the substrate; and
an expansion capacitor disposed in the substrate and connected to the second floating diffusion region through a metal line,
wherein the expansion capacitor has a region overlapping at least one first pixel among the plurality of first pixels in a direction perpendicular to the upper surface of the substrate.

15. The image sensor of claim 14 , wherein the plurality of first pixels are arranged to surround the at least one second pixel.

16. The image sensor of claim 14 , wherein a width of each of the plurality of first pixels is equal to a width of the at least one second pixel in the direction parallel to the upper surface of the substrate.

17. The image sensor of claim 14 , wherein the expansion capacitor is a metal-insulator-metal (MIM) capacitor.

18. The image sensor of claim 14 , wherein the expansion capacitor is a poly-insulator-poly (PIP) capacitor.

Assignees

• Samsung Electronics Co Ltd

Inventors

• Baek Ingyu
• Kim Seungsik

Classifications

• H04N23/843 Primary

  Demosaicing, e.g. interpolating colour pixel values · CPC title

• H04N25/583

  with different integration times · CPC title

• H04N25/585

  with pixels having different sensitivities within the sensor, e.g. fast or slow pixels or pixels having different sizes · CPC title

• H04N25/13

  characterised by the spectral characteristics of the filter elements · CPC title

• H04N25/778

  comprising amplifiers shared between a plurality of pixels, i.e. at least one part of the amplifier must be on the sensor array itself · CPC title