CN114500893A - Image sensor, control method thereof and display panel - Google Patents
Image sensor, control method thereof and display panel Download PDFInfo
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- CN114500893A CN114500893A CN202210093651.4A CN202210093651A CN114500893A CN 114500893 A CN114500893 A CN 114500893A CN 202210093651 A CN202210093651 A CN 202210093651A CN 114500893 A CN114500893 A CN 114500893A
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
- H04N25/00—Circuitry of solid-state image sensors [SSIS]; Control thereof
- H04N25/70—SSIS architectures; Circuits associated therewith
- H04N25/71—Charge-coupled device [CCD] sensors; Charge-transfer registers specially adapted for CCD sensors
- H04N25/75—Circuitry for providing, modifying or processing image signals from the pixel array
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
- H04N25/00—Circuitry of solid-state image sensors [SSIS]; Control thereof
- H04N25/70—SSIS architectures; Circuits associated therewith
- H04N25/79—Arrangements of circuitry being divided between different or multiple substrates, chips or circuit boards, e.g. stacked image sensors
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Abstract
The invention discloses an image sensor, a control method thereof and a display panel, wherein the image sensor comprises a reset module, an amplification module, a reading module and a gain-adjustable photoelectric conversion module; the control end of the reset module is connected with the reset signal end, the first end of the reset module is connected with the first power supply module, and the second end of the reset module is connected with the control end of the amplification module; the first end of the amplifying module is connected with the second power supply module, and the second end of the amplifying module is connected with the first end of the reading module; the first end of the photoelectric conversion module is connected with the bias power supply module, and the second end of the photoelectric conversion module is connected with the control end of the amplification module; the control end of the reading module is connected with the signal reading end, and the second end of the reading module is connected with the signal output end. The gain-adjustable photoelectric conversion module can realize the minimization of capacitance, improve the signal-to-noise ratio, realize the maximization of capacitance and ensure the strong light resistance.
Description
Technical Field
The invention relates to the technical field of display, in particular to an image sensor, a control method thereof and a display panel.
Background
An Active Pixel Sensor (APS) structure includes a photodiode, a reset transistor, an Active amplifier transistor, and a readout transistor.
The APS has advantages of an improved signal-to-noise ratio and higher sensitivity because of the active amplification tube. In the APS, the photodiode is equivalent to a photodiode and a capacitor, and in order to improve the amplification effect of the signal, the capacitor needs to be reduced as much as possible to achieve a larger capacitance gain, and accordingly, the photosensitive area of the photodiode needs to be reduced, but the strong light resistance of the APS is reduced.
Disclosure of Invention
In view of the above-mentioned drawbacks and deficiencies of the prior art, it is desirable to provide an image sensor, a control method thereof, and a display panel.
In a first aspect, an embodiment of the present invention provides an image sensor, including a reset module, an amplification module, a reading module, and a gain-adjustable photoelectric conversion module;
the control end of the reset module is connected with a reset signal end, the first end of the reset module is connected with the first power supply module, and the second end of the reset module is connected with the control end of the amplification module;
the first end of the amplifying module is connected with the second power supply module, and the second end of the amplifying module is connected with the first end of the reading module;
the first end of the photoelectric conversion module is connected with the bias power supply module, and the second end of the photoelectric conversion module is connected with the control end of the amplification module;
the control end of the reading module is connected with the signal reading end, and the second end of the reading module is connected with the signal output end;
the reset module is used for resetting the control end of the amplification module under the control of the reset signal end;
the photoelectric conversion module is used for converting an optical signal into an electric signal under the action of the bias power supply module after the control end of the amplification module is reset, and transmitting the electric signal to the control end of the amplification module;
the amplifying module is used for transmitting the electric signal to a first end of the reading signal in a conducting state;
the reading module is used for transmitting the electric signal to the signal output end under the control of the reading signal end.
Further, the photoelectric conversion module includes: the bias power supply module comprises at least two bias power supply ends, the first end of each light-sensitive diode is connected with one bias power supply end, at least two light-sensitive diodes are respectively connected with two different bias power supply ends, and the second end of each light-sensitive diode is connected with the control end of the amplification module.
Further, each bias power supply end of the bias power supply module corresponds to each photodiode of the photoelectric conversion module one to one.
Further, the reset module includes a first transistor, a control terminal of the first transistor is the control terminal of the reset module, a first terminal of the first transistor is the first terminal of the reset module, and a second terminal of the second transistor is the second terminal of the reset module.
Further, the amplifying module includes the second transistor, a control end of the second transistor is a control end of the amplifying module, a first end of the second transistor is a first end of the amplifying module, and a second end of the second transistor is a second end of the amplifying module.
Further, the reading module includes a third transistor, a control end of the third transistor is a control end of the reading module, a first end of the third transistor is a first end of the reading module, and a second end of the third transistor is a second end of the reading module.
Further, the image sensor comprises a substrate base plate, a circuit layer and a photosensitive device function layer which are sequentially stacked, the reset module, the amplification module and the reading module are arranged in the circuit layer, and the photoelectric conversion circuit is arranged in the photosensitive device function layer;
the photosensitive device functional layer comprises at least two photosensitive diodes, and the orthographic projections of the photosensitive diodes on the substrate are sequentially sleeved from inside to outside and distributed at intervals.
Furthermore, the orthographic projection of the photosensitive diode positioned at the center in the photosensitive device functional layer on the substrate base plate is in an elliptical structure, and the orthographic projection of the rest of the photosensitive diodes on the substrate base plate is in an elliptical ring structure;
or the orthographic projection of the photosensitive diode positioned at the center in the photosensitive device functional layer on the substrate base plate is in a circular structure, and the orthographic projections of the rest photosensitive diodes on the substrate base plate are in a circular structure;
or the orthographic projection of the photosensitive diode positioned at the center in the photosensitive device functional layer on the substrate base plate is of a rectangular structure, and the orthographic projections of the rest photosensitive diodes on the substrate base plate are of a rectangular annular structure.
In a second aspect, an embodiment of the present invention provides a display panel, including a plurality of image sensors as described in the first aspect.
In a third aspect, an embodiment of the present invention provides a method for controlling an image sensor, including:
a reset stage: the reset signal is input to the reset signal end to control the conduction of the reset module so as to reset the control end of the amplification module;
and (3) an exposure stage: stopping inputting a reset signal to the reset signal end to close the reset module, and controlling the gain-adjustable photoelectric conversion module to convert an optical signal into an electric signal by inputting a bias signal to the bias power supply module;
a reading stage: and controlling the reading module to be conducted to read out the electric signal by providing a data reading signal to the signal reading end.
The technical scheme provided by the embodiment of the invention can have the following beneficial effects:
according to the image sensor, the preparation method, the control method and the display panel provided by the embodiment of the invention, at least two photosensitive diodes connected in parallel are arranged in the photoelectric conversion module, and the on/off of each photosensitive diode is controlled by matching each bias power line, so that the capacitors of different gears (different sizes) can be provided, the maximization of signal gain is realized when the minimization of the capacitors is realized, the signal to noise ratio is improved, and the sensitivity of the photosensitive is improved; and the requirement of the image sensor on strong light resistance can be met when the capacitance maximization is realized.
Drawings
Other features, objects and advantages of the invention will become more apparent upon reading of the detailed description of non-limiting embodiments made with reference to the following drawings:
fig. 1 is a schematic block diagram of an image sensor provided in an embodiment of the present invention;
fig. 2 is a circuit diagram of an image sensor according to an embodiment of the present invention;
FIG. 3 is a schematic block diagram of another image sensor provided by an embodiment of the present invention;
FIG. 4 is a circuit diagram of another image sensor provided in an embodiment of the present invention;
fig. 5 is a block flow diagram of a method for manufacturing an image sensor according to an embodiment of the present invention;
fig. 6 is a schematic structural diagram of an image sensor according to an embodiment of the present invention;
FIG. 7 is an orthographic view of a photodiode on a substrate in an image sensor according to an embodiment of the present invention;
FIG. 8 is another orthographic view of a photodiode on a substrate in an image sensor according to an embodiment of the invention;
fig. 9 is a schematic structural diagram of a display panel according to an embodiment of the present invention.
Detailed Description
The present invention will be described in further detail with reference to the accompanying drawings and examples. It is to be understood that the specific embodiments described herein are merely illustrative of the relevant invention and not restrictive of the invention. It should be noted that, for convenience of description, only the portions related to the present invention are shown in the drawings.
Unless defined otherwise, technical or scientific terms used herein shall have the ordinary meaning as understood by one of ordinary skill in the art to which this invention belongs. The use of "first," "second," and similar terms in this disclosure is not intended to indicate any order, quantity, or importance, but rather is used to distinguish one element from another. The word "comprising" or "comprises", and the like, means that the element or item listed before the word covers the element or item listed after the word and its equivalents, but does not exclude other elements or items.
In the description of the present invention, it is to be understood that the terms "central," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," "circumferential," and the like are used in the orientations and positional relationships indicated in the drawings for convenience in describing the invention and to simplify the description, and are not intended to indicate or imply that the referenced device or element must have a particular orientation, be constructed and operated in a particular orientation, and are not to be considered limiting of the invention.
In the description of the present invention, it should be noted that, unless otherwise explicitly specified or limited, the terms "mounted," "connected," and "connected" are to be construed broadly, e.g., as meaning either a fixed connection, a removable connection, or an integral connection; can be mechanically or electrically connected; the two elements may be directly connected or indirectly connected through an intermediate medium, or may be communicated with each other inside the two elements, or may be wirelessly connected or wired connected. The specific meanings of the above terms in the present invention can be understood in specific cases to those skilled in the art.
It should be noted that the embodiments and features of the embodiments of the present invention may be combined with each other without conflict. The present invention will be described in detail below with reference to the embodiments with reference to the attached drawings.
As shown in fig. 1, an embodiment of the present invention provides an image sensor, including a reset module 11, an amplification module 12, a reading module 13, and a photoelectric conversion module 14;
the control end of the reset module 11 is connected with the reset signal end Vrst, the first end of the reset module 11 is connected with the first power module Vdr, and the second end of the reset module 11 is connected with the control end of the amplifying module 12;
the first end of the amplifying module 12 is connected to the second power module Vdd, and the second end of the amplifying module 12 is connected to the first end of the reading module 13;
a first end of the photoelectric conversion module 14 is connected with the bias power supply module, and a second end of the photoelectric conversion module 14 is connected with the control end of the amplification module 12;
the control end of the reading module 13 is connected with the signal reading end Vread, and the second end of the reading module 13 is connected with the signal output end Vout;
the reset module 11 is configured to reset the control end of the amplification module 12 under the control of the reset signal end Vrst;
the photoelectric conversion module 14 is configured to convert an optical signal into an electrical signal under the action of the bias power supply module after the control end of the amplification module 12 is reset, and transmit the electrical signal to the control end of the amplification module 12;
the amplifying module 12 is configured to transmit the electrical signal to a first end of the reading module 13 in a conducting state;
the reading module 13 is configured to transmit an electrical signal to the signal output terminal Vout under the control of the read signal terminal Vread.
In the image sensor provided by this embodiment, the reset module 11 is connected to the reset signal terminal Vrst, and the reset module 11 is turned on in response to the reset signal to transmit the first power signal Vdd to the first node N1, so as to reset the control terminal of the amplifying module 12;
stopping inputting a reset signal into the reset signal terminal Vrst, inputting a bias signal into the bias power supply module, and controlling the photoelectric conversion module 14 to convert an optical signal into an electric signal;
then, a data reading signal is provided to the signal reading terminal Vread, and the reading module 13 is controlled to be turned on to read out an electrical signal.
The photoelectric conversion module 14 can provide capacitors of different gears (i.e., different sizes) by matching with a bias power supply input by each bias power line in the first power supply end, that is, the capacitance can be adjusted under the condition of maximizing the photosensitive area, the maximization of signal gain is realized when the capacitance is minimized, the signal to noise ratio is improved, and the sensitivity of photosensitive is improved; and the requirement of the image sensor on strong light resistance can be met when the capacitance maximization is realized.
The structural composition and the operation principle of the image sensor are described in detail below.
As a possible implementation, the photoelectric conversion module 14 includes at least two photodiodes connected in parallel, and the number of the photodiodes may be two, three, four or more; the bias power supply module comprises at least two bias power supply terminals, such as a first bias power supply terminal Vbias1 and a second bias power supply terminal Vbias2, wherein the number of the bias power supply terminals is not more than the number of the photosensitive diodes; the first end of each photosensitive diode is connected with one bias power supply end, at least two photosensitive diodes are respectively connected with two different bias power supply ends, and the second end of each photosensitive diode is connected with the control end of the amplification module.
For example, the photoelectric conversion module comprises three photodiodes connected in parallel, the bias power supply module comprises two bias power supply terminals, the first ends of the two photodiodes are connected with one bias power supply terminal, the first end of the remaining one photodiode is connected with the other bias power supply terminal, and each photodiode comprises a capacitor, so that 3 capacitor gears with different sizes can be provided.
Further, each bias power supply end of the bias power supply module corresponds to each photodiode of the photoelectric conversion module one to one.
As shown in fig. 2, the photoelectric conversion module 14 preferably includes three photo diodes, a first photo diode includes a first capacitor C1, a second photo diode includes a second capacitor C2, a third photo diode includes a third capacitor C3, and three bias power supply terminals, which are a first bias power supply terminal Vbias1, a second bias power supply terminal Vbias2 and a third bias power supply terminal Vbias3, respectively, a first terminal of the first photo diode is connected to Vbias1, a first terminal of the second photo diode is connected to Vbias2, and a first terminal of the third photo diode is connected to Vbias 3.
When one, two or all of the Vbias1, Vbias2 and Vbias3 are selectively input with reverse bias signals, capacitance gears with different sizes in 6, such as C1, C2, C3, C1+ C2, C2+ C3, C1+ C2+ C3, can be realized, so that the image sensor has the performance of adjustable gain, the smaller the capacitance, the smaller the gain, the larger the signal-to-noise ratio, and the more sensitive the sensor; for example, the capacitance is C1+ C2, the voltage of the third bias power supply terminal Vbias3 connected to the first terminal of the third photodiode is equal to the voltage of the control terminal of the amplifying module 12, and the capacitor C3 discharges, but the I layer of the third photodiode is still a photosensitive layer, so that the preset value of each bias signal can be adjusted under the condition of maximizing the photosensitive area, thereby adjusting the size of the capacitor. When Vbias1, Vbias2 and Vbias3 are all reverse bias signals, capacitance maximization can be achieved, and the image sensor has strong light resistance.
As a possible implementation, the reset module 11 includes a first transistor T1, a control terminal of the first transistor T1 is a control terminal of the reset module 11, a first terminal of the first transistor T1 is a first terminal of the reset module 11, and a second terminal of the second transistor T2 is a second terminal of the reset module. Specifically, the reset module 11 includes a first transistor T1, a control terminal of the first transistor T1 is connected to the reset signal terminal Vrst, a first terminal of the first transistor T1 is connected to a first power source terminal, that is, the first terminal of the first transistor T1 is connected to the first power source signal Vdr, and a second terminal of the first transistor T1 is connected to the first node N1.
As a possible implementation, the amplifying module 12 includes a second transistor T2, the control terminal of the second transistor T2 is the control terminal of the amplifying module 12, the first terminal of the second transistor T2 is the first terminal of the amplifying module 12, and the second terminal of the second transistor T2 is the second terminal of the amplifying module 12. Specifically, the amplifying module 12 includes a second transistor T2, a control terminal of the second transistor T2 is connected to the first node N1, a first terminal of the second transistor T2 is connected to a second power supply terminal Vdd, that is, the first terminal of the second transistor T2 is connected to the second power supply signal Vdd, and a second terminal of the second transistor T2 is connected to the second node N2.
As a possible implementation manner, the read module 13 includes a third transistor T3, a control terminal of the third transistor T3 is a control terminal of the read module 13, a first terminal of the third transistor T3 is a first terminal of the read module 13, and a second terminal of the third transistor T3 is a second terminal of the read module 13. Specifically, the reading module includes a third transistor T3, a control terminal of the third transistor T3 is connected to the signal reading terminal Vread, a first terminal of the third transistor T3 is connected to the second node N2, and a second terminal of the third transistor T3 is connected to the signal output terminal Vout.
In various embodiments of the present invention, each transistor has a control terminal, a first terminal, and a second terminal. Specifically, the control terminal of each transistor may be a gate, the first terminal may be a source, and the second terminal may be a drain; alternatively, the control terminal of each transistor may be a gate, the first terminal may be a drain, and the second terminal may be a source. Each transistor may be an enhancement transistor or a depletion transistor, which is not particularly limited in the embodiments of the present invention.
As an alternative embodiment, all the transistors may be N-type thin film transistors, and the driving voltage of each transistor is a high level voltage. Alternatively, all the transistors may be P-type thin film transistors, and the driving voltage of each transistor is a low level voltage.
In a specific implementation, a reset signal input through the reset signal terminal Vrst turns on the first transistor T1, resets the control terminal of the second transistor T2, and charges a capacitor included in the photodiode;
stopping inputting the reset signal, turning off the corresponding first transistor T1, inputting a bias power supply to each bias power line, irradiating the photodiode with light to compound charges at two ends of the capacitor, lowering the charge amount on the photodiode, lowering the potential of the PD point, and operating the second transistor T2 in saturationIn the saturation region, the source potential of the second transistor T2 causes the current I flowing through the second transistor T2DS(ii) a change;
by inputting a data read signal to the signal read terminal Vread, the third transistor T3 is controlled to be turned on, so that the current I is enabledDSAnd out through the signal output terminal Vout.
In the image sensor illustrated in fig. 1 and 2, the first power signal Vdr to which the reset module 11 is connected and the second power signal Vdd to which the amplification module 12 is connected are different signals.
Referring to fig. 3 and 4, another image sensor is provided according to an embodiment of the present invention. The differences from the image sensor illustrated in fig. 1 and 2 are: the first power supply signal and the second power supply signal are both Vdd; a first end of the first transistor T1 of the reset module 11 and a first end of the second transistor T2 of the amplifying module 12 are both connected to a second power supply signal Vdd; the rest of the structure can refer to the image sensor illustrated in fig. 1 and 2.
The designer can reasonably set the first power supply signal and the second power supply signal according to the working process of the image sensor.
Referring to fig. 5, an embodiment of the present invention further provides a method for manufacturing an image sensor, including the steps of:
s101: forming a circuit layer on one side of the substrate base plate;
s103: forming a bottom electrode layer on one side of the circuit layer, which is far away from the substrate base plate;
s105: forming a photosensitive device layer on one side of the bottom electrode layer, which is far away from the substrate;
s107: forming a top electrode layer on one side of the photosensitive device layer, which is far away from the substrate;
the top electrode layer comprises top electrodes which correspond to the photosensitive diodes one to one, each top electrode is connected with one bias power supply end, and the top electrodes corresponding to at least two photosensitive diodes are connected with different bias signal ends.
In a specific implementation process, a buffer blocking layer is formed above a substrate, and a circuit layer is formed on one side of the buffer blocking layer away from the substrate, wherein the circuit layer comprises a polycrystalline silicon layer, a first insulating layer, a gate layer, a second insulating layer and a source drain layer. The circuit layer in this embodiment includes, in a broad scope, the first transistor T1, the second transistor T2, and the third transistor T3, which are not particularly limited to any one of the transistors; the circuit layer is buffered and protected by the blocking buffer layer;
forming a bottom electrode layer on the side of the circuit layer far away from the substrate base plate, wherein the bottom electrode layer comprises: forming a flat layer, a first passivation layer and a bottom electrode layer on one side of the source drain electrode layer, which is far away from the substrate base plate, wherein the bottom electrode layer is connected with a source electrode or a drain electrode through a via hole which penetrates through the first passivation layer and the flat layer;
forming a photosensitive device layer on one side of the bottom electrode layer far away from the substrate base plate, wherein the photosensitive device layer comprises: sequentially forming an N layer, an I layer and a P layer on one side of the bottom electrode, which is far away from the substrate base plate, namely forming the PIN photosensitive diode; forming a cap-shaped protective layer on one side of the P layer, which is far away from the substrate base plate, wherein the material of the protective layer can be Indium Tin Oxide (ITO), and the protective layer can also be called an ITO-cap layer; forming a resin insulating layer on one side of the ITO-cap layer, which is far away from the substrate, wherein the resin insulating layer has a good adhesion effect with the first passivation layer, and forms a good coating on the photosensitive device layer;
forming a top electrode layer on one side of the photosensitive device layer far away from the substrate base plate, wherein the method comprises the following steps: and forming a second passivation layer on one side of the resin insulation layer far away from the substrate base plate, forming a top electrode layer on one side of the second passivation layer far away from the substrate base plate, wherein the top electrode layer comprises top electrodes corresponding to the photosensitive diodes, and the top electrodes are connected with the ITO-cap layers of the corresponding photosensitive diodes through via holes penetrating through the second passivation layer and the resin insulation layer.
As an optional implementation manner, the method for manufacturing an image sensor provided in this embodiment further includes:
and forming a bridging metal layer on one side of the top electrode layer, which is far away from the substrate base plate, wherein the bridging metal layer comprises bridging metals which are in one-to-one correspondence with the photosensitive diodes, and each top electrode is connected with a corresponding bias power supply end through the corresponding bridging metal.
Specifically, a third passivation layer is formed on one side of the top electrode layer away from the substrate, and a bridging metal layer is formed on one side of the passivation layer away from the substrate, so that the top electrode corresponding to each photodiode is connected to the corresponding bias power supply terminal through the corresponding bridging metal.
As an optional implementation manner, the method for manufacturing an image sensor provided in this embodiment further includes: and a fourth passivation layer is formed on one side of the bridging metal layer, which is far away from the substrate base plate, and an anti-static layer is formed on one side of the fourth passivation layer, which is far away from the substrate base plate, wherein the anti-static layer is made of ITO (indium tin oxide), and can be also called a Top-ITO layer, so that an anti-static effect is achieved.
Referring to fig. 6, the image sensor according to the embodiment of the present invention includes a substrate 21, a circuit layer 23, and a photosensitive device functional layer, which are sequentially stacked, wherein a reset module, an amplification module, and a reading module are disposed in the circuit layer, and a photoelectric conversion circuit is disposed in the photosensitive device functional layer; the functional layer of the photosensitive device comprises at least two photosensitive diodes, and orthographic projections of the at least two photosensitive diodes on the substrate are in a structure which is sequentially sleeved from inside to outside and distributed at intervals.
In some alternative embodiments, a buffer barrier layer 22 is disposed between the substrate base plate 21 and the circuit layer 23 to form buffer protection for the circuit layer 23;
a bottom electrode layer 26, a photosensitive device layer 27, a TIO-cap layer 29, a resin insulating layer 29, a second passivation layer 30, a Top electrode layer 31, a third passivation layer 32, a bridging metal layer 33, a fourth passivation layer 34 and a Top-ITO layer 35 are sequentially arranged on one side of the circuit layer 23 away from the substrate;
the circuit layer 23 includes a polysilicon layer 221, a first insulating layer 222, a gate layer 223, a second insulating layer 224 and a source drain layer 225, which are stacked, two first via holes are disposed on the second insulating layer 224 and the first insulating layer 222, and the source and the drain are electrically connected to the active layer through the corresponding first via holes;
the photosensitive device functional layer comprises a bottom electrode layer 26, a photosensitive device layer 27, a TIO-cap layer 28 and a top electrode layer 31 which are sequentially stacked; the flat layer 24 and the first passivation layer 25 are provided with a second via hole, and the bottom electrode layer 26 passes through the corresponding second via hole to be electrically connected with the source electrode or the drain electrode;
a plurality of third through holes are formed in the second passivation layer 30 and the resin insulation layer 29, the number of the third through holes is equal to the number of the photosensitive diodes, and each top electrode penetrates through the corresponding third through hole to be connected with the corresponding ITO-cap of each photosensitive device layer;
a plurality of fourth via holes are formed in the third passivation layer 32, the number of the fourth via holes is equal to the number of the photodiodes, and the bridging metal corresponding to each top electrode passes through the corresponding fourth via hole to be connected with each top electrode.
Further, referring to fig. 7, the orthographic projection of the central photodiode in the photosensitive device layer 27 on the substrate 21 is in a rectangular structure, and the orthographic projections of the rest photodiodes on the substrate 21 are in a rectangular ring structure. That is, the image sensor is rectangular, can maximize the space of the pixels, and is beneficial to realizing the maximization of the capacitance and the maximization of the photosensitive area.
Alternatively, referring to fig. 8, the orthographic projection of the central photodiode in the photosensitive device layer 27 on the substrate 21 is an elliptical structure, and the orthographic projections of the rest photodiodes on the substrate 21 are elliptical ring structures. So more be close to the line shape of fingerprint, can be as much as possible acquire fingerprint information, under the condition that DPI (number of points per inch) improves, the cockscomb structure problem of image cockscomb structure can effectively be avoided in rectangular design is compared in the oval formula design.
Alternatively, the orthographic projection of the central photodiode in the photosensitive device layer 27 on the substrate 21 is in a circular structure, and the orthographic projections of the rest photodiodes on the substrate 21 are in a circular ring structure. Under the condition that DPI improves, circular form design can promote the utilization to the pixel space to a certain extent in comparing in oval form design, compares and also can avoid the cockscomb structure problem to a certain extent in rectangle form design.
In fig. 7 and 8, the image sensor includes three photodiodes, which are a first photodiode, a second photodiode, and a third photodiode from inside to outside in sequence, and corresponding capacitors are C1, C2, and C3, respectively.
Referring to fig. 9, an embodiment of the present invention also provides a display panel including a plurality of image sensors as described above.
For example, the image sensors are distributed to cover a display area AA of the display panel, the image sensors are distributed in an array, a plurality of bias power lines are arranged in a non-display area of the display panel surrounding the display area AA, each photodiode in each image sensor has a bias power line in one-to-one correspondence, and a first end of each photodiode in each image sensor is connected with a corresponding bias power line. Alternatively, the plurality of image sensors are distributed in a partial area of the display area AA of the display panel.
The embodiment of the invention also provides a control method of the image sensor, which comprises a reset stage, an exposure stage and a reading stage which are sequentially carried out.
In the reset phase, a reset signal is input to the end of a reset signal Vrst to control the reset module 11 to be conducted so as to reset the control end of the amplification module 12;
in the exposure phase, the input of the reset signal to the reset signal terminal is stopped to turn off the reset module 11, and a signal is provided to the bias power supply modules (i.e., the respective bias power supply terminals) to control the photoelectric conversion module 14 to convert the optical signal into an electrical signal;
in the read phase, the read module 13 is controlled to be turned on to read out the electrical signal by providing a data read signal to the signal read terminal Vread.
The size of the capacitor in the photoelectric conversion module can be adjusted by presetting each bias power supply, so that the maximization of gain is realized when the minimization of the capacitor is realized, the signal-to-noise ratio is improved, and the photosensitive sensitivity of the image sensor is ensured; the resistance of the image sensor to strong light can be improved under the condition of maximizing the capacitance.
The foregoing description is only exemplary of the preferred embodiments of the invention and is illustrative of the principles of the technology employed. It will be appreciated by those skilled in the art that the scope of the invention is not limited to the specific combination of the above-mentioned features, but also encompasses other embodiments in which any combination of the above-mentioned features or their equivalents is possible without departing from the inventive concept. For example, the above features and (but not limited to) features having similar functions disclosed in the present invention are mutually replaced to form the technical solution.
Claims (10)
1. An image sensor is characterized by comprising a reset module, an amplification module, a reading module and a gain-adjustable photoelectric conversion module;
the control end of the reset module is connected with a reset signal end, the first end of the reset module is connected with the first power supply module, and the second end of the reset module is connected with the control end of the amplification module;
the first end of the amplifying module is connected with the second power supply module, and the second end of the amplifying module is connected with the first end of the reading module;
the first end of the photoelectric conversion module is connected with the bias power supply module, and the second end of the photoelectric conversion module is connected with the control end of the amplification module;
the control end of the reading module is connected with the signal reading end, and the second end of the reading module is connected with the signal output end;
the reset module is used for resetting the control end of the amplification module under the control of the reset signal end;
the photoelectric conversion module is used for converting an optical signal into an electric signal under the action of the bias power supply module after the control end of the amplification module is reset, and transmitting the electric signal to the control end of the amplification module;
the amplifying module is used for transmitting the electric signal to a first end of the reading signal in a conducting state;
the reading module is used for transmitting the electric signal to the signal output end under the control of the reading signal end.
2. The image sensor according to claim 1, wherein the photoelectric conversion module comprises: the bias power supply module comprises at least two bias power supply ends, the first end of each light-sensitive diode is connected with one bias power supply end, at least two light-sensitive diodes are respectively connected with two different bias power supply ends, and the second end of each light-sensitive diode is connected with the control end of the amplification module.
3. The image sensor as claimed in claim 2, wherein each bias power terminal of the bias power supply module corresponds to each photodiode of the photoelectric conversion module one to one.
4. The image sensor of claim 1, wherein the reset module comprises a first transistor, a control terminal of the first transistor is a control terminal of the reset module, a first terminal of the first transistor is a first terminal of the reset module, and a second terminal of the second transistor is a second terminal of the reset module.
5. The image sensor of claim 1, wherein the amplifying module comprises the second transistor, a control terminal of the second transistor is a control terminal of the amplifying module, a first terminal of the second transistor is a first terminal of the amplifying module, and a second terminal of the second transistor is a second terminal of the amplifying module.
6. The image sensor of claim 1, wherein the read module comprises a third transistor, a control terminal of the third transistor is a control terminal of the read module, a first terminal of the third transistor is a first terminal of the read module, and a second terminal of the third transistor is a second terminal of the read module.
7. The image sensor according to any one of claims 1 to 6, wherein the image sensor includes a substrate, a circuit layer, and a photosensitive device functional layer, which are sequentially stacked, the reset module, the amplification module, and the reading module are provided in the circuit layer, and the photoelectric conversion circuit is provided in the photosensitive device functional layer;
the photosensitive device functional layer comprises at least two photosensitive diodes, at least two photosensitive diodes are in orthographic projection on the substrate is of a structure which is sequentially sleeved from inside to outside and distributed at intervals.
8. The image sensor as claimed in claim 7, wherein the central photodiode in the photosensitive device functional layer has an elliptical orthographic projection on the substrate, and the rest photodiodes have an elliptical orthographic projection on the substrate;
or the orthographic projection of the photosensitive diode positioned at the center in the photosensitive device functional layer on the substrate base plate is in a circular structure, and the orthographic projections of the rest photosensitive diodes on the substrate base plate are in a circular structure;
or the orthographic projection of the photosensitive diode positioned at the center in the photosensitive device functional layer on the substrate base plate is of a rectangular structure, and the orthographic projections of the rest photosensitive diodes on the substrate base plate are of a rectangular annular structure.
9. A display panel comprising a plurality of image sensors according to any one of claims 1 to 5.
10. A method of controlling an image sensor, comprising:
a reset stage: the reset signal is input to the reset signal end to control the conduction of the reset module so as to reset the control end of the amplification module;
and (3) an exposure stage: stopping inputting a reset signal to the reset signal end to close the reset module, and controlling the gain-adjustable photoelectric conversion module to convert an optical signal into an electric signal by inputting a bias signal to the bias power supply module;
a reading stage: and controlling the reading module to be conducted to read out the electric signal by providing a data reading signal to the signal reading end.
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