CN112261322B

CN112261322B - Image sensor

Info

Publication number: CN112261322B
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: 2023-05-23
Anticipated expiration: 2040-10-19
Also published as: CN112261322A

Abstract

The invention discloses a graph 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. 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 of the pixel array, and the area utilization rate of the image sensor is improved; or to increase the image sensor function by using non-effective 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 various fields such as electronic consumption, security monitoring, automatic control, medical treatment, national defense and the like. The field of application is also expanding, and recent solid-state image sensors are also used for off-screen fingerprint detection.

In the prior art, a conventional solid-state image sensor is shown in fig. 1a and 1b, and 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; wherein the pixel array 101 is an array formed by sequentially arranging pixels. In similar aperture array imaging applications, reference is made to patent PCT/US2016/033731, where 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 imaging area of the pinhole array is an array formed by pinholes 202, and the actual effective image is formed by imaging and stitching the effective imaging area 203 inside each pinhole 202, where the effective imaging area 203 is generally square. In the pixel array 201, the pixels of the non-effective imaging region 203 are useless. The diagonal of the effective imaging area 203 does not generally exceed the diameter of the aperture 202, assuming the aperture 202 diameter is 2*R, the aperture 202 area is pi R2, and the square area 203 does not exceed 2R 2; therefore, in similar aperture array imaging applications, the area of at least the ratio (pi-1)/pi in the pixel array is useless, resulting in chip waste.

Disclosure of Invention

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

The invention aims at realizing the following technical scheme:

the image sensor of the invention comprises a sub-image unit array 301, a peripheral digital module 302 and a reference voltage generator 303, wherein the sub-image unit array 301 is formed by sequentially arranging a plurality of sub-image units 304 into an array.

According to the technical scheme provided by the invention, the image sensor provided by the embodiment of the invention utilizes the ineffective imaging area of the traditional image sensor to place part of the ineffective imaging square area of the pixel array in the traditional solid-state image sensor, so that the area utilization rate of the image sensor is improved; or to increase the image sensor function by using non-effective imaging areas in the pixel array.

Drawings

Fig. 1a and 1b are respectively exemplary diagrams of a conventional solid-state image sensor and a pixel array thereof in the prior art;

FIG. 2 is an exemplary illustration of an imaging region of a small hole array;

fig. 3a, fig. 3b, and fig. 3c are respectively exemplary structural diagrams of an image sensor, a sub-image unit thereof, and a non-pixel module according to an embodiment of the present invention;

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

Detailed Description

Embodiments of the present invention will be described in further detail below. What is not described in detail in the embodiments of the present invention belongs to the prior art known to those skilled in the art.

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

the image sensor comprises a sub-image cell array 301, a peripheral digital module 302 and a reference voltage generator 303, wherein the sub-image cell array 301 is formed by sequentially arranging a plurality of sub-image cells 304 into an array.

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

The non-pixel module 306 includes 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 the signals generated by the pixels, the analog-to-digital converter 308 converts the analog signals output by the pixel signal reading circuit 307 into digital signals, and the sub-image unit digital module 309 functions to receive the signals from the peripheral digital module 302, thereby generating signals required for controlling the operation of the sub-image unit 304, and the following control is implemented 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 to operate, the output of the analog-to-digital converter 308 is controlled to be transmitted to the sub-image unit digital module 309, and the signal generated by the sub-image unit digital module 309 is transmitted to the peripheral digital module 302.

The peripheral digital module 302 functions to control the exposure and signal readout of the sub-pixel array 305 in the sub-image unit array 301, and transmit these signals to the sub-image unit digital module 309 in the sub-image unit array 301;

the peripheral digital module 302 receives signals output from the sub-picture element digital module 309 in the sub-picture element 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 of the invention 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-image cells are arranged in an array of sub-image cells. 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.

Specific examples:

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

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

The sub-picture element digital block 309 receives the signals from the peripheral digital block 302 and generates the control signals necessary to control the operation of the sub-picture element 304. With these signals, 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 controlled to be 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 unit digital module 309 may also contain memory that stores data generated by sub-image unit 304 over a period of time.

The peripheral digital module 302 functions to generate control signals required to control each sub-picture element 304 in the sub-picture element array 301, to receive output signals from each sub-picture element 304 in the sub-picture element array 301, and to store and process these signals.

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

Fig. 4 shows an example of a pixel cell structure, a readout circuit and an analog-to-digital converter that may be employed in a sub-image cell in an image sensor according to the present disclosure. FIG. 4 shows a column of pixels in a subpixel array; the readout circuitry and analog-to-digital converter of the example of fig. 4 are implemented in the form of column circuitry. The pixel unit 401 of the example of fig. 4 is a 4T pixel unit structure formed by sequentially connecting a photodiode 402, a transfer 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 sequentially connected 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 of the column of pixel signals. The bias voltage pixel_bias of the Pixel output load 407 in the Pixel readout circuit and the comparator 408 input signal Ramp 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 circuits and analog-to-digital converters in the sub-image cells of the example shown in fig. 4 are implemented in column circuit form, 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 employ a set of pixel signal reading circuits and analog-to-digital converters corresponding to one column of pixels, and the image sensor disclosed in the present invention may also employ a set 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 monoclinic analog-to-digital converter, and the image sensor disclosed in the invention can also adopt an SAR or Cyclic analog-to-digital converter.

The foregoing is only a preferred embodiment of the present invention, but the scope of the present invention is not limited thereto, and any changes or substitutions easily contemplated by those skilled in the art within the scope of the present invention should be included in the scope of the present invention. Therefore, the protection scope of the present invention should be subject to the protection scope of the claims.

Claims

1. An image sensor, characterized in that the image sensor comprises a sub-image unit array (301), a peripheral digital module (302) and a reference voltage generator (303), wherein the sub-image unit array (301) is formed by sequentially arranging a plurality of sub-image units (304) into an array;

the sub-image unit (304) comprises 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 the analog signals output by the pixel signal reading circuit (307) into digital signals, and the sub-image unit digital module (309) functions to receive the 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 by the signals:

controlling exposure and signal readout of the sub-pixel array (305), controlling the operation of the pixel signal reading circuit (307) and the analog-to-digital converter (308), controlling the output of the analog-to-digital converter (308) to be transmitted to the sub-image unit digital module (309), and transmitting the signal generated by the sub-image unit digital module (309) to the peripheral digital module (302);

the peripheral digital module (302) can generate and control the exposure and signal readout of the sub-pixel array (305) in the sub-image unit array (301), and transmit the signals to the sub-image unit digital module (309) in the sub-image unit 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.

2. The image sensor according to claim 1, wherein the reference voltage generator (303) is operative to generate a reference voltage or a reference current to be supplied to the sub-picture element array (301).