CN110379824A - A kind of cmos image sensor and image processing method, storage medium - Google Patents

Abstract

Embodiments of the present application provide a CMOS image sensor, an image processing method, and a storage medium. The CMOS image sensor includes: triangular pixel units arranged in a hexagonal array, wherein the triangular pixel unit is provided with a photodiode PD column, and the triangular pixel unit uses The PD column absorbs RGB monochromatic light and converts the corresponding optical signal into an electrical signal; the CMOS pixel readout circuit connected with the triangular pixel unit is used to amplify the electrical signal and read out the electrical signal.

Description

A CMOS image sensor, image processing method, and storage medium

technical field

The present application relates to the field of image processing, and in particular, to a CMOS image sensor, an image processing method, and a storage medium.

Background technique

A commonly used pixel array is mainly formed by arranging square pixels, the pixels are of a square structure, and the horizontal and vertical periods are also the same.

In the prior art, a square pixel unit in a complementary metal oxide semiconductor (Complementary Metal Oxide Semiconductor, CMOS) image sensor can be arranged with a photodiode (PhotoDiode, PD) structure to perform light absorption and photoelectric conversion. As shown in FIG. 1 , a PD structure can be set in each square pixel unit, the square pixel units are arranged in a quadrangular array, and the corresponding RGB monochromatic light is absorbed by the pixel units in the positive direction, so that the arrangement of the pixel units The cloth density is low, which in turn results in a low pixel density of the CMOS image sensor.

SUMMARY OF THE INVENTION

Embodiments of the present application provide a CMOS image sensor, an image processing method, and a storage medium, which can improve the arrangement density of pixel units and the pixel density of the CMOS image sensor.

The technical solution of the present application is realized as follows:

An embodiment of the present application provides a CMOS image sensor, and the CMOS image sensor includes:

According to the triangular pixel unit arranged in a hexagonal array, the triangular pixel unit is provided with a photodiode PD column, and the triangular pixel unit utilizes the PD column to absorb RGB monochromatic light, and convert the corresponding optical signal into an electrical signal;

A CMOS pixel readout circuit connected to the triangular pixel unit is used for amplifying the electrical signal and reading out the electrical signal.

In the above CMOS image sensor, the hexagonal array of the triangular pixel units is arranged such that six triangular pixel units converge at one point to form a regular hexagon.

In the above CMOS image sensor, the size of the PD column is determined based on the resonance wavelength of the RGB monochromatic light and the refractive index of the optical signal.

In the above CMOS image sensor, if the RGB monochromatic light is red light, the size of the PD column is a first size that supports absorbing the red light;

If the RGB monochromatic light is green light, the size of the PD column is a second size that supports absorbing the green light;

If the RGB monochromatic light is blue light, the size of the PD column is a third size that supports absorption of the blue light.

In the above CMOS image sensor, the shape of the PD column at least includes a rectangle, a circle, a parallelogram and a rhombus.

In the above CMOS image sensor, the CMOS pixel readout circuit includes: a transfer transistor connected to the PD column, a readout area connected to the transfer transistor, and an amplifier tube connected to the readout area;

the transfer transistor for transferring the electrical signal from the PD column to a readout area to read the electrical signal from the readout area;

The amplifying tube is used for amplifying the electrical signal in the readout area.

In the above CMOS image sensor, the CMOS pixel readout circuit further comprises: a reset transistor connected to the readout region and the amplifier tube;

the readout area is also used to read out the reset level in the reset transistor;

The amplifying tube is also used for amplifying the reset level.

An embodiment of the present application provides an image processing method, which is applied to a CMOS image sensor composed of triangular pixel units arranged in a hexagonal array and a CMOS pixel readout circuit, wherein the triangular pixel unit is provided with a photodiode PD column, and the Methods include:

Use the PD column to absorb RGB monochromatic light and convert the corresponding optical signal into an electrical signal;

The electrical signal is amplified by the CMOS pixel readout circuit, and the electrical signal is read out.

In the above method, the hexagonal array of the triangular pixel units is arranged such that six triangular pixel units converge at one point to form a regular hexagon.

An embodiment of the present application provides a storage medium on which a computer program is stored, which is applied to a CMOS image sensor, and when the computer program is executed by a processor, implements any of the methods described above.

Embodiments of the present application provide a CMOS image sensor, an image processing method, and a storage medium. The CMOS image sensor includes: triangular pixel units arranged in a hexagonal array, wherein the triangular pixel unit is provided with a photodiode PD column, and the triangular pixel unit uses The PD column absorbs RGB monochromatic light and converts the corresponding optical signal into an electrical signal; the CMOS pixel readout circuit connected with the triangular pixel unit is used to amplify the electrical signal and read out the electrical signal. With the above implementation solution, the shape of the pixel units in the CMOS image sensor is triangular, and the triangular pixel units are arranged in a hexagonal array. The arrangement of pixel units with higher density enables the CMOS image sensor to obtain more pixels, thereby increasing the pixel density of the CMOS image sensor.

Description of drawings

1 is a schematic diagram of the arrangement of PD columns in a pixel unit proposed in the prior art;

FIG. 2 is a schematic structural diagram of a CMOS image sensor provided by an embodiment of the present application;

3 is a schematic top view of an exemplary arrangement of PDs in a single pixel unit provided by an embodiment of the present application;

FIG. 4 is a schematic structural diagram of an exemplary pixel array arrangement provided by an embodiment of the present application;

FIG. 5 is a schematic diagram of a circuit structure of an exemplary single pixel unit circuit provided by an embodiment of the present application;

FIG. 6 is a flowchart of an image processing method provided by an embodiment of the present application.

Detailed ways

It should be understood that the specific embodiments described herein are merely illustrative of the present application. It is not intended to limit this application.

Example 1

An embodiment of the present application provides a CMOS image sensor. As shown in FIG. 2 , the CMOS image sensor includes:

According to the triangular pixel unit arranged in a hexagonal array, the triangular pixel unit is provided with a photodiode PD column, and the triangular pixel unit utilizes the PD column to absorb RGB monochromatic light, and convert the corresponding optical signal into an electrical signal;

A CMOS pixel readout circuit connected to the triangular pixel unit is used for amplifying the electrical signal and reading out the electrical signal.

A CMOS image sensor provided by an embodiment of the present application is suitable for a scenario where an optical signal is collected and the collected optical signal is subjected to image processing to obtain an image corresponding to the optical signal.

In the embodiment of the present application, the CMOS image sensor is composed of a pixel unit circuit and a CMOS circuit, wherein the pixel unit circuit is used to convert the collected optical signal into an electrical signal, and the electrical signal is read out, and the CMOS circuit is used to analyze the electrical signal. Perform image processing to obtain an image corresponding to the optical signal.

In the embodiment of the present application, the pixel unit circuit is composed of a pixel unit and a CMOS pixel readout circuit, wherein the shape of the pixel unit is an equilateral triangle, and each triangular pixel unit includes a PD column, and the PD column absorbs RGB single pixels according to different sizes. For color light, as shown in Figure 3, a single triangular pixel unit includes a PD column with a diameter of 90 nm for absorbing green light.

In the embodiments of the present application, the material of the PD column is silicon material.

It should be noted that, in the embodiments of the present application, the multiple PD pillars in the pixel unit are all 100-nanometer-level PD pillars, and the optical density of states in the PD pillar structure is higher than that of the traditional PD structure due to optical resonance.

In the embodiment of the present application, the triangular pixel unit utilizes the optical resonance principle of the PD column to absorb RGB monochromatic light and RGB combined light, and its absorption rate is as high as 95%, and the optical resonance makes the optical density of states in the cylindrical PD structure higher than the traditional The PD structure further improves the quantum efficiency and signal-to-noise ratio of the CMOS image sensor, and further reduces the pixel size.

In the embodiments of the present application, the side lengths of the triangular pixel units may be determined according to actual pixel density requirements or process manufacturing requirements, which are not specifically limited in the embodiments of the present application.

Optionally, the hexagonal array of the triangular pixel units is arranged such that six triangular pixel units converge at one point to form a regular hexagon.

In the embodiment of the present application, as shown in FIG. 4 , the hexagonal array arrangement of the triangular pixel units is as follows: two adjacent triangular pixel units are connected on one side, so that six triangular pixel units that converge at one point form a regular hexagon, Thus, the pixel units are arranged in a hexagonal close-packed array structure, and at this time, the PD pillars in the six triangular pixel units also form a regular hexagon.

Optionally, the size of the PD column is determined based on the resonant wavelength of RGB monochromatic light and the refractive index of the optical signal.

In the embodiment of the present application, the diameter of the PD column is determined based on the resonant wavelength of the RGB monochromatic light and the refractive index of the optical signal, or is obtained through optical simulation, and is specifically selected according to the actual situation, which is not specified in the embodiment of the present application. limited.

In the embodiment of the present application, the size of the PD column is determined by using the formula (1)

Size of PD column = (resonance wavelength - preset constant)/refractive index (1)

Exemplarily, the diameter of the corresponding PD column when absorbing blue light is about 60 nm; when absorbing green light, the corresponding PD column has a diameter of 90 nm; when absorbing red light, the corresponding diameter of the PD column is 120 nm.

In the embodiment of the present application, the pixel unit utilizes the optical resonance of the PD column to achieve resonance absorption of RGB monochromatic light and RGB combined light.

Optionally, if the RGB monochromatic light is red light, the size of the PD column is the first size that supports absorbing the red light;

If the RGB monochromatic light is green light, the size of the PD column is a second size that supports absorbing the green light;

If the RGB monochromatic light is blue light, the size of the PD column is a third size that supports absorption of the blue light.

In the embodiment of the present application, one pixel unit can actually only realize the absorption of RGB monochromatic light, that is, the absorption of one color light among red light, green light, and blue light, and the target sizes of the multiple PD columns included are actually all Supports the size that absorbs the corresponding color light. That is to say, for a pixel unit, if the target monochromatic light absorbed by the pixel unit is red light, the target size corresponding to the multiple PD columns included in the pixel unit is the first size, that is, the size that supports the absorption of red light. Correspondingly, for a pixel unit, if the target monochromatic light absorbed by the pixel unit is green light, the target size corresponding to the multiple PD columns included in the pixel unit is the second size, that is, the size that supports the absorption of green light. Similarly, for a pixel unit, if the target monochromatic light absorbed by it is blue light, the target size corresponding to the multiple PD columns included in the pixel unit is the third size, that is, the size that supports the absorption of blue light. The specific first size, second size, and third size are not limited in the embodiments of the present application.

Optionally, the shape of the PD column includes at least a rectangle, a circle, a parallelogram, and a rhombus, which are specifically selected according to actual conditions, which are not specifically limited in the embodiments of the present application.

Optionally, the CMOS pixel readout circuit includes: a transfer transistor connected to the PD column, a readout area connected to the transfer transistor, and an amplifier tube connected to the readout area;

the transfer transistor for transferring the electrical signal from the PD column to a readout area to read the electrical signal from the readout area;

The amplifying tube is used for amplifying the electrical signal in the readout area.

In the embodiment of the present application, the source of the transfer transistor is connected to the n region of the PD column; the drain of the transfer transistor is connected to the FD; the PD column focuses the electrical signal to the n+ region of the transfer transistor, and is transferred to the FD through the transfer transistor .

In the embodiment of the present application, the light is photoelectrically converted in the depletion region of the PD column, and the optical signal is converted into an electrical signal, and then the transfer transistor gathers the electrical signal into the channel of the n+ region of the transfer transistor; The signal is transferred to FD.

Optionally, the CMOS pixel readout circuit further includes: a reset transistor connected to the readout area and the amplifier tube;

the readout area is also used to read out the reset level in the reset transistor;

The amplifying tube is also used for amplifying the reset level.

In the embodiment of the present application, the source of the reset transistor is connected to the power supply; the drain of the reset transistor is connected to the FD, wherein the reset transistor stores the reset level, and the reset level is read out through the FD.

In the embodiment of the present application, the reset level is read out from the reset transistor and the electrical signal is read out from the transfer transistor, respectively, and after the reset level and the electrical signal are amplified, the amplified electrical signal and the amplified reset level are correlated and compared. sampling, thereby reducing the noise of the readout electrical signal.

As shown in Figure 5, it is a simplified schematic diagram of a single pixel unit circuit, in which the n region of the PD column is connected to the source of the transfer transistor, and the drain of the transfer transistor is connected to the FD; the FD is also connected to the drain of the reset transistor, which resets the The source of the tube is connected to the power supply; the FD is also connected to the gate of the BSF, the source of the BSF is connected to the power supply, the drain of the BSF is connected to the source of the strobe, and the drain of the strobe is connected to the output terminal.

It can be understood that the shape of the pixel units in the CMOS image sensor is triangular, and the triangular pixel units are arranged in a hexagonal array. The arrangement of pixel units with higher density enables the CMOS image sensor to obtain more pixels, thereby increasing the pixel density of the CMOS image sensor.

Embodiment 2

The embodiment of the present application provides an image processing method, which is applied to a CMOS image sensor composed of triangular pixel units arranged in a hexagonal array and a CMOS pixel readout circuit. The triangular pixel unit is provided with a photodiode PD column, as shown in FIG. 6 . shown, the method includes:

S101, using the PD column to absorb RGB monochromatic light, and converting the corresponding optical signal into an electrical signal.

An image processing method provided by an embodiment of the present application is suitable for a scenario where a CMOS image sensor is used to collect an optical signal and perform image processing on the collected optical signal to obtain an image corresponding to the optical signal.

In the embodiment of the present application, the CMOS image sensor is composed of a pixel unit circuit and a CMOS circuit, wherein the pixel unit circuit is used to convert the collected optical signal into an electrical signal, and the electrical signal is read out, and the CMOS circuit is used to analyze the electrical signal. Perform image processing to obtain an image corresponding to the optical signal.

In the embodiment of the present application, the pixel unit circuit is composed of a pixel unit and a CMOS pixel readout circuit, wherein the shape of the pixel unit is an equilateral triangle, and each triangular pixel unit includes a PD column, and the PD column absorbs RGB single pixels according to different sizes. For color light, as shown in Figure 2, a single triangular pixel unit includes a PD column with a diameter of 90 nm for absorbing green light.

In the embodiments of the present application, the material of the PD column is silicon material.

It should be noted that, in the embodiments of the present application, the multiple PD pillars in the pixel unit are all 100-nanometer-level PD pillars, and the optical density of states in the PD pillar structure is higher than that of the traditional PD structure due to optical resonance.

In the embodiment of the present application, the pixel unit circuit utilizes the optical resonance principle of the PD column to absorb RGB monochromatic light and RGB combined light, and its absorption rate is as high as 95%, and the optical resonance makes the optical density of states in the cylindrical PD structure higher than that of traditional The PD structure further improves the quantum efficiency and signal-to-noise ratio of the CMOS image sensor, and further reduces the pixel size.

Optionally, the size of the PD column is determined based on the resonant wavelength of the RGB monochromatic light and the refractive index of the optical signal.

In the embodiment of the present application, the diameter of the PD column is determined based on the resonant wavelength of the RGB monochromatic light and the refractive index of the optical signal, or is obtained through optical simulation, and is specifically selected according to the actual situation, which is not specified in the embodiment of the present application. limited.

In the embodiment of the present application, the size of the PD column is determined by using the formula (1)

Size of PD column = (resonance wavelength - preset constant)/refractive index (1)

Exemplarily, the diameter of the corresponding PD column when absorbing blue light is about 60 nm; when absorbing green light, the corresponding PD column has a diameter of 90 nm; when absorbing red light, the corresponding diameter of the PD column is 120 nm.

In the embodiments of the present application, the side lengths of the triangular pixel units may be determined according to actual pixel density requirements or process manufacturing requirements, which are not specifically limited in the embodiments of the present application.

Optionally, the hexagonal array of the triangular pixel units is arranged such that six triangular pixel units converge at one point to form a regular hexagon.

In the embodiment of the present application, as shown in FIG. 3 , the hexagonal array arrangement of the triangular pixel units is as follows: one side of two adjacent triangular pixel units is connected, so that the six triangular pixel units that converge at one point form a regular hexagon, Thus, the pixel units are arranged in a hexagonal close-packed array structure, and at this time, the PD pillars in the six triangular pixel units also form a regular hexagon.

In the embodiment of the present application, the triangular pixel units arranged in a hexagonal array use a PD column with a preset size to absorb the corresponding RGB monochromatic light, and then the RGB monochromatic light is converted into light spots in the PD column, and the corresponding optical signal is converted into an electrical signal.

S102, using a CMOS pixel readout circuit to amplify the electrical signal, and read out the electrical signal.

After the pixel unit circuit uses the PD column to absorb RGB monochromatic light and converts the corresponding optical signal into an electrical signal, the pixel unit circuit uses the CMOS pixel readout circuit to amplify the electrical signal and read out the electrical signal.

In the embodiment of the present application, the CMOS pixel readout circuit includes: a transfer transistor connected to the PD column, a readout area connected to the transfer transistor, and an amplifier tube connected to the readout area; the pixel unit circuit uses the transfer transistor to convert electrical signals from the PD The column is transferred to the readout area; after that, the electrical signal is read from the readout area; and the electrical signal in the readout area is amplified by an amplifying tube.

In the embodiment of the present application, the source of the transfer transistor is connected to the n region of the PD column; the drain of the transfer transistor is connected to the FD; the PD column focuses the electrical signal to the n+ region of the transfer transistor, and is transferred to the FD through the transfer transistor.

In the embodiment of the present application, the light is photoelectrically converted in the depletion region of the PD column, and the optical signal is converted into an electrical signal, and then the transfer transistor gathers the electrical signal into the channel of the n+ region of the transfer transistor; The signal is transferred to FD.

Optionally, the CMOS pixel readout circuit further includes: a reset transistor connected to the readout area and the amplifier tube; wherein, the readout area is also used to read out the reset level in the reset transistor; the amplifier tube is also used to The reset level is amplified.

In the embodiment of the present application, the source of the reset transistor is connected to the power supply; the drain of the reset transistor is connected to the FD, wherein the reset transistor stores the reset level, and the reset level is read out through the FD.

In the embodiment of the present application, the reset level is read out from the reset transistor and the electrical signal is read out from the transfer transistor, respectively, and after the reset level and the electrical signal are amplified, the amplified electrical signal and the amplified reset level are correlated and compared. sampling, thereby reducing the noise of the readout electrical signal.

It can be understood that the shape of the pixel units in the CMOS image sensor is triangular, and the triangular pixel units are arranged in a hexagonal array. The arrangement of pixel units with higher density enables the CMOS image sensor to obtain more pixels, thereby increasing the pixel density of the CMOS image sensor.

Embodiment 3

An embodiment of the present application provides a storage medium on which a computer program is stored, the computer-readable storage medium stores one or more programs, and the one or more programs can be executed by one or more processors and applied to pixels In the unit circuit, the computer program implements the image processing method described in the second embodiment.

Specifically, when a program instruction corresponding to an image processing method in this embodiment is read or executed by an electronic device, the following steps are included:

Use the PD column to absorb RGB monochromatic light and convert the corresponding optical signal into an electrical signal;

The electrical signal is amplified by the CMOS pixel readout circuit, and the electrical signal is read out.

In the embodiment of the present invention, further, the hexagonal array of the triangular pixel units is arranged such that six triangular pixel units converge at one point to form a regular hexagon.

The above descriptions are only preferred embodiments of the present application, and are not intended to limit the protection scope of the present application.

Claims (10)

1. A CMOS image sensor, wherein the CMOS image sensor comprises: According to the triangular pixel unit arranged in a hexagonal array, the triangular pixel unit is provided with a photodiode PD column, and the triangular pixel unit utilizes the PD column to absorb RGB monochromatic light, and convert the corresponding optical signal into an electrical signal; A CMOS pixel readout circuit connected to the triangular pixel unit is used for amplifying the electrical signal and reading out the electrical signal. 2 . The CMOS image sensor according to claim 1 , wherein the hexagonal array of the triangular pixel units is arranged such that six triangular pixel units converge at one point to form a regular hexagon. 3 . 3 . The CMOS image sensor according to claim 1 , wherein the size of the PD column is determined based on the resonant wavelength of RGB monochromatic light and the refractive index of the optical signal. 4 . 4. The CMOS image sensor according to claim 1, wherein, If the RGB monochromatic light is red light, the size of the PD column is the first size that supports absorbing the red light; If the RGB monochromatic light is green light, the size of the PD column is a second size that supports absorbing the green light; If the RGB monochromatic light is blue light, the size of the PD column is a third size that supports absorption of the blue light. 5 . The CMOS image sensor according to claim 1 , wherein the shape of the PD column at least includes a rectangle, a circle, a parallelogram, and a rhombus. 6 . 6 . The CMOS image sensor according to claim 1 , wherein the CMOS pixel readout circuit comprises: a transfer transistor connected to the PD column, a readout region connected to the transfer transistor, and a readout region connected to the PD column. 7 . Amplifying tube connected to the readout area; the transfer transistor for transferring the electrical signal from the PD column to a readout area to read the electrical signal from the readout area; The amplifying tube is used for amplifying the electrical signal in the readout area. 7. The pixel unit circuit according to claim 1, wherein the CMOS pixel readout circuit further comprises: a reset transistor connected to the readout region and the amplifier; the readout area is also used to read out the reset level in the reset transistor; The amplifying tube is also used for amplifying the reset level. 8. An image processing method, applied to a CMOS image sensor composed of triangular pixel units arranged in a hexagonal array and a CMOS pixel readout circuit, wherein the triangular pixel unit is provided with a photodiode PD column, wherein the The methods described include: Use the PD column to absorb RGB monochromatic light and convert the corresponding optical signal into an electrical signal; The electrical signal is amplified by the CMOS pixel readout circuit, and the electrical signal is read out. 9 . The method according to claim 8 , wherein the hexagonal array of the triangular pixel units is arranged such that six triangular pixel units converge at a point to form a regular hexagon. 10 . 10. A storage medium on which a computer program is stored and applied to a CMOS image sensor, characterized in that, when the computer program is executed by a processor, the method according to any one of claims 8-9 is implemented.