CN112261322A

CN112261322A - Image sensor

Info

Publication number: CN112261322A
Application number: CN202011117358.4A
Authority: CN
Inventors: 旷章曲; 保罗·维克伯特; 刘志碧; 陈杰
Original assignee: Beijing Superpix Micro Technology Co Ltd
Current assignee: Beijing Superpix Micro Technology Co Ltd
Priority date: 2020-10-19
Filing date: 2020-10-19
Publication date: 2021-01-22
Anticipated expiration: 2040-10-19
Also published as: CN112261322B

Abstract

The invention discloses a graphic sensor, which at least comprises a sub-image unit array, a peripheral digital module, a reference voltage generator and other components, wherein the sub-image unit array is formed by arranging sub-image units into an array; the sub-image unit consists of a sub-pixel array and a non-pixel module; the non-pixel module at least comprises a pixel signal reading circuit, an analog-to-digital converter and a sub-image unit digital module. Partial non-pixel circuits in the traditional solid-state image sensor are placed in a non-effective imaging square area in a pixel array by utilizing a non-effective imaging area of the traditional image sensor, so that the area utilization rate of the image sensor is improved; or to increase the image sensor function by using non-active imaging areas in the pixel array.

Description

Image sensor

Technical Field

The present invention relates to a Solid-state image sensor (Solid-state image sensor), and more particularly, to an image sensor.

Background

The solid-state image sensor is widely applied to the fields of electronic consumption, security monitoring, automatic control, medical treatment, national defense and the like. The application field is expanding, and recently, the solid-state image sensor is also used for detecting finger print under the screen.

In the prior art, a structure of a conventional solid-state image sensor is shown in fig. 1a and 1b, and the conventional solid-state image sensor includes a pixel array 101, a row control 102, a pixel signal reading circuit 103, an analog-to-digital converter 104, a digital module 105, and a reference voltage generator 106; the pixel array 101 is an array formed by sequentially arranging pixels. In applications like aperture array imaging, see patent PCT/US2016/033731, only a portion of the area of the pixel array receives the light signal.

As shown in fig. 2, in the pixel array 201, the aperture array imaging area is an array formed by apertures 202, the actual effective image is formed by imaging and splicing an effective imaging area 203 inside each aperture 202, and the effective imaging area 203 is generally square. In the pixel array 201, the pixels of the non-effective imaging region 203 are useless. Typically the diagonal of the effective imaging area 203 does not exceed the diameter of the aperture 202, assuming the diameter of the aperture 202 is 2R, the area of the aperture 202 is pi R2, and the area of the square area 203 does not exceed 2R 2; thus, in aperture array-like imaging applications, it is not useful to have at least the (pi-1)/pi area of the pixel array, resulting in wasted chips.

Disclosure of Invention

An object of the present invention is to provide an image sensor.

The purpose of the invention is realized by the following technical scheme:

the image sensor of the present invention includes a sub-image cell array 301, a peripheral digital module 302, and a reference voltage generator 303, the sub-image cell array 301 being formed by sequentially arranging a plurality of sub-image cells 304 in an array.

According to the technical scheme provided by the invention, the image sensor provided by the embodiment of the invention has the advantages that the non-effective imaging area of the traditional image sensor is utilized, part of non-pixel circuits in the traditional solid-state image sensor are placed in the non-effective imaging square area in the pixel array, and the area utilization rate of the image sensor is improved; or to increase the image sensor function by using non-active imaging areas in the pixel array.

Drawings

Fig. 1a and 1b are schematic diagrams of a conventional solid-state image sensor and a pixel array thereof, respectively;

FIG. 2 is an exemplary view of an imaging area of an aperture array;

fig. 3a, fig. 3b, and fig. 3c are schematic diagrams illustrating structures of an image sensor and a sub-image unit and a non-pixel module thereof according to an embodiment of the invention;

fig. 4 is an exemplary diagram of a pixel unit, a pixel signal reading circuit, and an analog-to-digital converter in a sub-image unit according to an embodiment of the invention.

Detailed Description

The embodiments of the present invention will be described in further detail below. Details which are not described in detail in the embodiments of the invention belong to the prior art which is known to the person skilled in the art.

The image sensor of the present invention has the following preferred embodiments:

the image sensor includes a sub-image cell array 301, a peripheral digital module 302, and a reference voltage generator 303, the sub-image cell array 301 being sequentially arranged in an array by a plurality of sub-image cells 304.

The sub-image cell 304 includes a sub-pixel array 305 and a non-pixel module 306.

The non-pixel module 306 comprises a pixel signal reading circuit 307, an analog-to-digital converter 308, and a sub-image unit digital module 309.

The pixel signal reading circuit 307 is responsible for reading out signals generated by the pixels, the analog-to-digital converter 308 converts analog signals output by the pixel signal reading circuit 307 into digital signals, and the sub-image unit digital module 309 function includes receiving signals of the peripheral digital module 302, thereby generating signals required for controlling the operation of the sub-image unit 304, and the following control is realized through the signals:

controls the exposure and signal readout of the sub-pixel array 305, controls the pixel signal reading circuit 307 and the analog-to-digital converter 308 to work, controls the output of the analog-to-digital converter 308 to be transmitted to the sub-image unit digital module 309, and transmits the signal generated by the sub-image unit digital module 309 to the peripheral digital module 302.

The peripheral digital module 302 is used for generating and controlling the exposure and signal readout of the sub-pixel array 305 in the sub-image cell array 301, and transmitting the signals to the sub-image cell digital module 309 in the sub-image cell array 301;

the peripheral digital module 302 receives the signals output by the sub-image unit digital module 309 in the sub-image unit array 301, and stores and processes the signals.

The reference voltage generator 303 functions to generate a reference voltage or a reference current to be supplied to the sub-picture cell array 301.

The image sensor divides the pixel array of the traditional solid-state image sensor into a plurality of sub-pixel arrays, and properly divides some peripheral circuits of the traditional solid-state image sensor into a plurality of sub-circuits; the sub-pixel array and the sub-circuit form a sub-image unit; the sub-picture elements are arranged in an array of sub-picture elements. The image sensor disclosed by the invention is composed of a sub-image unit array, a peripheral digital module, a reference voltage generator and the like.

The specific embodiment is as follows:

as shown in fig. 3a, 3b, and 3c, the image sensor includes a sub-image cell array 301, a peripheral digital module 302, and a reference voltage generator 303.

The sub-image cell array 301 is formed by sequentially arranging the sub-image cells 304 as shown in fig. 3a, 3b, and 3 c. Sub-image element 304 is comprised of sub-pixel array 305 and non-pixel module 306; the sub-pixel array 305 is formed by sequentially arranging pixel units; the non-pixel module 306 is composed of a pixel signal reading circuit 307, an analog-to-digital converter 308, and a sub-image unit digital module 309. Under the control of the sub-image unit digital module 309, the sub-pixel array 305 converts the optical signal into an electrical signal and outputs the electrical signal to the pixel signal reading circuit 307. Under the control of the sub-image unit digital module 309, the pixel signal reading circuit 307 transmits the signal output by the sub-pixel array 305 to the analog-to-digital converter 308. Under the control of the sub-image unit digital block 309, the analog-to-digital converter 308 quantizes the output signal of the pixel signal reading circuit 307, generates a digital signal, and transmits the digital signal to the sub-image unit digital block 309.

The sub-image unit digital module 309 receives the signals from the peripheral digital module 302 and generates the control signals required to control the operation of the sub-image unit 304. By these signals, the exposure and signal readout of the sub-pixel array 305 are controlled, the pixel signal reading circuit 307 and the analog-to-digital converter 308 are controlled, and the output of the analog-to-digital converter 308 is transmitted to the sub-image unit digital block 309. Finally, the signals generated by the digital modules of the sub-image unit 304 are transmitted to the peripheral digital module 302. Sub-image cell number block 309 may also contain memory to store data generated by sub-image cells 304 over a period of time.

The peripheral digital module 302 functions include generating control signals required to control each sub-image cell 304 in the sub-image cell array 301, receiving output signals of each sub-image cell 304 in the sub-image cell array 301, and storing and processing the signals.

The reference voltage generator 303 generates a reference voltage or a reference current required for the sub-image cell array 301.

Fig. 4 shows an example of a pixel unit structure, a readout circuit and an analog-to-digital converter that may be adopted by a sub-image unit in an image sensor disclosed in the present invention. FIG. 4 shows a column of pixels in a sub-pixel array; the readout circuit and analog-to-digital converter of the example of fig. 4 are implemented in the form of column circuits. The pixel unit 401 in the example of fig. 4 is a 4T pixel unit structure, and the pixel unit structure is formed by sequentially connecting a photodiode 402, a transmission tube 403, a clear tube 404, a source follower tube 405, and a row selection tube 406. The outputs of the plurality of pixel units are connected in sequence to form a column of pixels. The pixel output is connected to a pixel output load tube 407 to generate a pixel readout circuit. The comparator 408 and the counter 409 form an analog-to-digital converter for the column of pixel signals. The bias voltage Pixel _ bias of the Pixel output load tube 407 and the input signal Ramp of the comparator 408 in the Pixel readout circuit are generated by the reference voltage generator 303 in fig. 3a, 3b, 3 c.

The pixel cell of the example shown in fig. 4 is a 4T pixel cell structure, and the image sensor disclosed in the present invention is not limited to the 4T pixel cell structure.

The readout circuit and the analog-to-digital converter in the sub-image unit of the example shown in fig. 4 are implemented in the form of column circuits, and the analog-to-digital converter of the image sensor disclosed in the present invention may be a global analog-to-digital converter

The readout circuit and the analog-to-digital converter in the sub-image unit of the example shown in fig. 4 use a group of pixel signal reading circuits and analog-to-digital converters corresponding to one column of pixels, and the image sensor disclosed by the invention can also use a group of pixel signal reading circuits and analog-to-digital converters corresponding to multiple columns of pixels

The analog-to-digital converter in the sub-image unit of the example shown in fig. 4 is a single-slope analog-to-digital converter, and the image sensor disclosed by the invention can also adopt a SAR or Cyclic analog-to-digital converter.

The above description is only for the preferred embodiment of the present invention, but the scope of the present invention is not limited thereto, and any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope of the present invention are included in the scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims.

Claims

1. An image sensor comprising a sub-image cell array (301), a peripheral digital module (302), and a reference voltage generator (303), the sub-image cell array (301) being arranged in an array by a plurality of sub-image cells (304) in sequence.

2. The image sensor of claim 1, wherein the sub-image cells (304) comprise a sub-pixel array (305) and a non-pixel module (306).

3. The image sensor of claim 2, wherein the non-pixel module (306) comprises a pixel signal reading circuit (307), an analog-to-digital converter (308), and a sub-image cell digital module (309).

4. The image sensor according to claim 3, wherein the pixel signal reading circuit (307) is responsible for reading out signals generated by the pixels, the analog-to-digital converter (308) converts analog signals output by the pixel signal reading circuit (307) into digital signals, and the sub-image unit digital module (309) function comprises receiving signals of the peripheral digital module (302), thereby generating signals required for controlling the sub-image unit (304) to operate, and the following control is realized through the signals:

the exposure and signal readout of the sub-pixel array (305) are controlled, the pixel signal reading circuit (307) and the analog-to-digital converter (308) are controlled to work, the output of the analog-to-digital converter (308) is controlled to be transmitted to the sub-image unit digital module (309), and signals generated by the sub-image unit digital module (309) are transmitted to the peripheral digital module (302).

5. The image sensor of claim 4, wherein the peripheral digital module (302) functions to control exposure and readout of the sub-pixel array (305) in the sub-image cell array (301) and to transmit the signals to the sub-image cell digital module (309) in the sub-image cell array (301);

the peripheral digital module (302) receives signals output by the sub-image unit digital module (309) in the sub-image unit array (301), and stores and processes the signals.

6. The image sensor according to any of claims 1 to 5, wherein the reference voltage generator (303) is operable to generate a reference voltage or a reference current for providing to the sub-image cell array (301).