CN114500893B - Image sensor, control method thereof and display panel - Google Patents
Image sensor, control method thereof and display panel Download PDFInfo
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- CN114500893B CN114500893B CN202210093651.4A CN202210093651A CN114500893B CN 114500893 B CN114500893 B CN 114500893B CN 202210093651 A CN202210093651 A CN 202210093651A CN 114500893 B CN114500893 B CN 114500893B
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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
Abstract
The invention discloses an image sensor, a control method thereof and a display panel, wherein the image sensor comprises a reset module, an amplifying 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 module, and the second end of the reset module is connected with the control end of the amplifying module; the first end of the amplifying module is connected with the second power 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 amplifying 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 not only realize the minimization of capacitance and improve the signal to noise ratio, but also 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
The structure of the active pixel sensor (Active Pixel Sensor, APS) includes a photodiode, a reset tube, an active amplifier tube, and a readout transistor.
The APS has advantages in terms of improved signal-to-noise ratio, and higher sensitivity, since it has an active amplifier. In the APS, the photodiode is equivalent to a photodiode and a capacitor, but in order to enhance the amplifying 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, which results in a decrease in the anti-glare capability of the APS.
Disclosure of Invention
In view of the foregoing drawbacks or shortcomings in 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, which is characterized by including a reset module, an amplifying 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 module, and the second end of the reset module is connected with the control end of the amplifying module;
the first end of the amplifying module is connected with the second power 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 amplifying 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 amplifying 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 amplifying module is reset, and transmitting the electric signal to the control end of the amplifying module;
the amplifying module is used for transmitting the electric signal to the first end of the reading module in a conducting state;
the reading module is used for transmitting the electric signal to the signal output end under the control of the signal reading end.
Further, the photoelectric conversion module includes: the bias power supply module comprises at least two parallel-connected light sensing diodes, wherein the first end of each light sensing diode is connected with one bias power supply end, at least two light sensing diodes are respectively connected with two different bias power supply ends, and the second end of each light sensing diode is connected with the control end of the amplifying module.
Further, each bias power supply end of the bias power supply module corresponds to each light sensing diode of the photoelectric conversion module one by one.
Further, the reset module includes a first transistor, a control end of the first transistor is a control end of the reset module, a first end of the first transistor is a first end of the reset module, and a second end of the first transistor is a second end of the reset module.
Further, the amplifying module includes a 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, a circuit layer and a photosensitive device functional layer which are sequentially stacked, wherein the reset module, the amplifying module and the reading module are arranged in the circuit layer, and the photoelectric conversion module is arranged in the photosensitive device functional layer;
the photosensitive device functional layer comprises at least two photosensitive diodes, and orthographic projections of the at least two photosensitive diodes on the substrate base plate are of a structure which is sleeved in sequence from inside to outside and distributed at intervals.
Further, the orthographic projection of the photosensitive diode positioned in the center of the photosensitive device functional layer on the substrate is in an elliptical structure, and the orthographic projections of the rest of photosensitive diodes on the substrate are in an elliptical ring structure;
or, orthographic projection of the photosensitive diode positioned in the center of the photosensitive device functional layer on the substrate is in a circular structure, and orthographic projections of the rest photosensitive diodes on the substrate are in a circular structure;
or, the orthographic projection of the photosensitive diode positioned in the center of the photosensitive device functional layer on the substrate is in a rectangular structure, and the orthographic projections of the rest of photosensitive diodes on the substrate are in 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:
and (3) a reset stage: the reset module is controlled to be conducted by inputting a reset signal to the reset signal end so as to reset the control end of the amplifying module;
exposure stage: stopping inputting a reset signal to the reset signal end to enable the reset module to be closed, and controlling the gain-adjustable photoelectric conversion module to convert the optical signal into an electric signal by inputting a bias signal to the bias power supply module;
reading: and the reading module is controlled 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 comprise 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 parallel-connected light-sensing diodes are arranged in the photoelectric conversion module, and the light-sensing diodes are controlled to be turned on or off by matching with each bias power line, so that capacitors with different gears (namely 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 sensitization is improved; and the requirements of the image sensor on strong light resistance can be met when the capacitance is maximized.
Drawings
Other features, objects and advantages of the present invention will become more apparent upon reading of the detailed description of non-limiting embodiments, made with reference to the accompanying drawings in which:
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 according to 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 a front view of a photodiode on a substrate in an image sensor according to an embodiment of the present invention;
FIG. 8 is another front view of a photodiode on a substrate in an image sensor according to an embodiment of the present invention;
fig. 9 is a schematic structural diagram of a display panel according to an embodiment of the invention.
Detailed Description
The invention is described in further detail below with reference to the drawings and examples. It is to be understood that the specific embodiments described herein are merely illustrative of the invention and are not limiting of the invention. It should be noted that, for convenience of description, only the portions related to the invention are shown in the drawings.
Unless defined otherwise, technical or scientific terms used in this disclosure should be given the ordinary meaning as understood by one of ordinary skill in the art to which this invention belongs. The terms "first," "second," and the like, as used in this disclosure, do not denote any order, quantity, or importance, but rather are used to distinguish one element from another. The word "comprising" or "comprises", and the like, means that elements or items preceding the word are included in the element or item listed after the word and equivalents thereof, but does not exclude other elements or items.
In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings are merely for convenience in describing the present invention and simplifying the description, and do not indicate or imply that the device or element being referred to must have a specific orientation, be configured and operated in a specific orientation, and therefore should not be construed as limiting the present invention.
In the description of the present invention, it should be noted that, unless explicitly specified and limited otherwise, the terms "mounted," "connected," and "connected" are to be construed broadly, and may be either fixedly connected, detachably connected, or integrally connected, for example; can be mechanically or electrically connected; the two components can be directly connected or indirectly connected through an intermediate medium, or can be communicated inside the two components, or can be connected wirelessly or in a wired way. The specific meaning of the above terms in the present invention will be understood in specific cases by those of ordinary skill in the art.
It should be noted that, without conflict, the embodiments of the present invention and features of the embodiments may be combined with each other. The invention will be described in detail below with reference to the drawings in connection with embodiments.
As shown in fig. 1, an embodiment of the present invention provides an image sensor, including a reset module 11, an amplifying module 12, a reading module 13, and a photoelectric conversion module 14;
the control end of the reset module 11 is connected with a 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 with the second power supply module Vdd, and the second end of the amplifying module 12 is connected with the first end of the reading module 13;
the first end of the photoelectric conversion module 14 is connected with the bias power supply module, and the second end of the photoelectric conversion module 14 is connected with the control end of the amplifying module 12;
the control end of the reading module 13 is connected with a signal reading end Vread, and the second end of the reading module 13 is connected with a signal output end Vout;
the reset module 11 is used for resetting the control end of the amplifying 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 module after the control end of the amplifying module 12 is reset, and transmit the electrical signal to the control end of the amplifying module 12;
the amplifying module 12 is configured to transmit an electrical signal to a first end of the reading module 13 in a conductive state;
the reading module 13 is configured to transmit an electrical signal to the signal output terminal Vout under the control of the signal reading terminal Vread.
In the image sensor provided in 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 to the reset signal terminal Vrst, inputting a bias signal to the bias power supply module, and controlling the photoelectric conversion module 14 to convert the optical signal into an electrical signal;
the data read signal is then supplied to the signal read terminal Vread, and the read block 13 is controlled to be turned on to read out the electric signal.
The gain of the photoelectric conversion module 14 is adjustable, the sensing diode is a PIN type sensing diode, the sensing diode can be equivalently used as a capacitor and a diode when working under the reverse voltage, and the photoelectric conversion module 14 can provide capacitors with different gears (namely different sizes) in cooperation with bias power supplies input by bias power lines in a first power supply end, namely, the capacitance can be adjusted under the condition that the photosensitive area is maximized, the maximization of the signal gain is realized when the capacitance is minimized, the signal to noise ratio is improved, and the sensitivity of the photosensitive is improved; and the requirements of the image sensor on strong light resistance can be met when the capacitance is maximized.
The structural composition and working principle of the image sensor are specifically described below.
As one possible embodiment, the photoelectric conversion module 14 includes at least two parallel-connected light-sensing diodes, and the number of light-sensing diodes 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 that of the sensing diodes; the first end of each light sensing diode is connected with one bias power supply end, at least two light sensing diodes are respectively connected with two different bias power supply ends, and the second end of each light sensing diode is connected with the control end of the amplifying module.
For example, the photoelectric conversion module comprises three parallel-connected sensing diodes, the bias power supply module comprises two bias power supply ends, wherein the first end of the two sensing diodes is connected with one bias power supply end, the first end of the remaining one sensing diode is connected with the other bias power supply end, and each sensing diode 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 light sensing diode of the photoelectric conversion module one by one.
As shown in fig. 2, the photoelectric conversion module 14 preferably includes three photodiodes, the first photodiode includes a first capacitor C1, the second photodiode includes a second capacitor C2, the third photodiode includes a third capacitor C3, and three bias power supply terminals, namely a first bias power supply terminal Vbias1, a second bias power supply terminal Vbias2 and a third bias power supply terminal Vbias3, are respectively corresponding to the third capacitor C3, a first terminal of the first photodiode is connected with Vbias1, a first terminal of the second photodiode is connected with Vbias2, and a first terminal of the third photodiode is connected with Vbias3.
When one, two or all of the Vbias1, the Vbias2 and the Vbias3 are selectively input into the reverse bias signals, the capacitive gears with different magnitudes in 6, such as C1, C2, C3, C1+C2, C2+C3 and C1+C2+C3, can be realized, so that the image sensor has the performance of adjustable gain, the smaller the capacitance is, the smaller the gain is, the larger the signal-to-noise ratio is, and the more sensitive the photosensitive performance of the sensor is; for example, when the capacitance is c1+c2, the voltage of the third bias power supply terminal Vbias3 connected to the first end 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 under the condition that the photosensitive area is maximized, the preset value of each bias signal can be adjusted, thereby adjusting the capacitance. 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 manner, 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 first transistor T1 is a second terminal of the reset module. Specifically, the reset module 11 includes a first transistor T1, a control end of the first transistor T1 is connected to the reset signal end Vrst, a first end of the first transistor T1 is connected to the first power end, that is, the first end of the first transistor T1 is connected to the first power signal Vdr, and a second end of the first transistor T1 is connected to the first node N1.
As a possible embodiment, 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 end of the second transistor T2 is connected to the first node N1, a first end of the second transistor T2 is connected to the second power supply Vdd, that is, the first end of the second transistor T2 is connected to the second power supply signal Vdd, and a second end of the second transistor T2 is connected to the second node N2.
As a possible implementation manner, the reading module 13 includes a third transistor T3, a control terminal of the third transistor T3 is a control terminal of the reading module 13, a first terminal of the third transistor T3 is a first terminal of the reading module 13, and a second terminal of the third transistor T3 is a second terminal of the reading module 13. Specifically, the reading module includes a third transistor T3, a control end of the third transistor T3 is connected to the signal reading end Vread, a first end of the third transistor T3 is connected to the second node N2, and a second end of the third transistor T3 is connected to the signal output end Vout.
In various embodiments of the present invention, each transistor has a control terminal, a first terminal, and a second terminal. Specifically, the control end of each transistor may be a gate, the first end may be a source, and the second end 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. In addition, 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 process, a reset signal input through a reset signal terminal Vrst can lead to the conduction of a first transistor T1, reset a control terminal of a second transistor T2, and charge a capacitor contained in a sensing diode;
stopping inputting reset signal, turning off the corresponding first transistor T1, inputting bias power to each bias power line, irradiating light on the photodiode to combine charges at two ends of the capacitor, decreasing charge amount on the photodiode, decreasing PD point potential, operating the second transistor T2 in saturation region, and causing current I flowing through the second transistor T2 due to source potential of the second transistor T2 in saturation region DS A change;
by inputting the data read signal to the signal read terminal Vread, the third transistor T3 is controlled to be turned on to enable the current I DS Flows out through the signal output terminal Vout.
In the image sensor illustrated in fig. 1 and 2, the first power signal Vdr connected to the reset module 11 and the second power signal Vdd connected to the amplifying module 12 are different signals.
Referring to fig. 3 and 4, another image sensor is provided according to an embodiment of the present invention. The difference from the image sensor illustrated in fig. 1 and 2 is that: the first power supply signal and the second power supply signal are Vdd; the first end of the first transistor T1 of the reset module 11 and the first end of the second transistor T2 of the amplifying module 12 are both connected with the second power supply signal Vdd; the rest of the structure may 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 a substrate;
s103: forming a bottom electrode layer on one side of the circuit layer away from the substrate;
s105: forming a photosensitive device layer on one side of the bottom electrode layer away from the substrate base plate;
s107: forming a top electrode layer on one side of the photosensitive device layer away from the substrate base plate;
the photosensitive device layer comprises at least two photosensitive diodes, the top electrode layer comprises top electrodes corresponding to the photosensitive diodes one by one, each top electrode is connected with one bias power supply end, and the top electrodes corresponding to the at least two photosensitive diodes are connected with different bias signal ends.
In a specific implementation process, a buffer barrier layer is formed above a substrate, and a circuit layer is formed on one side of the buffer barrier layer away from the substrate, wherein the circuit layer comprises a polysilicon layer, a first insulating layer, a gate layer, a second insulating layer and a source drain layer. The circuit layer in this embodiment includes the first transistor T1, the second transistor T2, and the third transistor T3 described above in a broad sense, and is not particularly limited to any one of them; buffering and protecting the circuit layer by the barrier buffer layer;
forming a bottom electrode layer on a side of the circuit layer away from the substrate base plate, comprising: forming a flat layer, a first passivation layer and a bottom electrode layer on one side of the source/drain electrode layer far away from the substrate, wherein the bottom electrode layer is connected with the source electrode or the drain electrode through a via hole penetrating through the first passivation layer and the flat layer;
forming a photosensitive device layer on a side of the bottom electrode layer away from the substrate base plate, comprising: sequentially forming an N layer, an I layer and a P layer on one side of the bottom electrode far away from the substrate, namely, forming a PIN sensing diode; forming a cap-shaped protective layer on one side of the P layer far away from the substrate, wherein the material of the cap-shaped 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 far away from the substrate, wherein the resin insulating layer has a good adhesion effect with the first passivation layer, and a good coating is formed on the photosensitive device layer;
forming a top electrode layer on a side of the photosensitive device layer away from the substrate base plate, comprising: and forming a second passivation layer on one side of the resin insulation layer far away from the substrate, forming a top electrode layer on one side of the second passivation layer far away from the substrate, wherein the top electrode layer comprises top electrodes corresponding to the light-sensing diodes, and the top electrodes are connected with the ITO-cap layers of the corresponding light-sensing diodes through the second passivation layer and the through holes of the resin insulation layer.
As an optional implementation manner, the method for manufacturing the image sensor provided in this embodiment further includes:
and forming a bridging metal layer on one side of the top electrode layer far away from the substrate base plate, wherein the bridging metal layer comprises bridging metals corresponding to the light-sensing diodes one by one, 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 light-sensing diode is connected to a corresponding bias power supply terminal through a corresponding bridging metal.
As an optional implementation manner, the method for manufacturing the image sensor provided in this embodiment further includes: and forming a fourth passivation layer on one side of the bridging metal layer far away from the substrate, and forming an antistatic layer on one side of the fourth passivation layer far away from the substrate, wherein the antistatic layer is made of ITO (indium tin oxide), and can be called as a Top-ITO layer, so that an antistatic effect is achieved.
Referring to fig. 6, the image sensor provided by the embodiment of the present invention includes a substrate 21, a circuit layer 23, and a photosensitive device functional layer that are sequentially stacked, a reset module, an amplifying module, and a reading module are disposed in the circuit layer, and a photoelectric conversion module is disposed in the photosensitive device functional layer; the photosensitive device functional layer comprises at least two photosensitive diodes, and orthographic projections of the at least two photosensitive diodes on the substrate are of a structure which is sleeved in sequence from inside to outside and distributed at intervals.
In some alternative embodiments, a buffer barrier layer 22 is provided between the substrate 21 and the circuit layer 23 to form buffer protection for the circuit layer 23;
the circuit layer 23 is provided with a bottom electrode layer 26, a photosensitive device layer 27, a TIO-cap layer 29, a resin insulation 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 in sequence on one side far 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 vias are disposed on the second insulating layer 224 and the first insulating layer 222, and the source and the drain pass through the corresponding first vias to be electrically connected with the active layer;
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 is electrically connected with the source electrode or the drain electrode through the corresponding second via hole;
the second passivation layer 30 and the resin insulating layer 29 are provided with a plurality of third through holes, the number of the third through holes is equal to that of the light sensing diodes, and each top electrode passes through the corresponding third through hole to be connected with the ITO-cap corresponding to each light sensing device layer;
the third passivation layer 32 is provided with a plurality of fourth vias, the number of which is equal to that of the light-sensing diodes, and the bridging metal corresponding to each top electrode passes through the corresponding fourth via to be connected with each top electrode.
Further, referring to fig. 7, the front projection of the central photodiode of the photosensitive device layer 27 on the substrate 21 has a rectangular structure, and the front projections of the rest photodiodes on the substrate 21 have a rectangular ring structure. That is, the image sensor has a rectangular shape, and can maximize the space for using pixels, thereby being beneficial to maximizing the capacitance and the photosensitive area.
Alternatively, referring to fig. 8, the orthographic projection of the central photodiode of the photosensitive device layer 27 on the substrate 21 has an elliptical structure, and the orthographic projections of the remaining photodiodes on the substrate 21 have an elliptical ring structure. So more be close to the line shape of fingerprint, can obtain fingerprint information as much as possible, under the circumstances that DPI (every inch point) improves, oval formula design compares in rectangular formula design can effectively avoid the problem of image cockscomb structure.
Alternatively, the front projection of the central photodiode of the photosensitive device layer 27 on the substrate 21 has a circular structure, and the front projections of the rest photodiodes on the substrate 21 have a circular structure. Under the condition that DPI improves, circular design can promote the utilization to the pixel space to a certain extent in comparison with oval formula design, also can avoid the cockscomb structure problem to a certain extent in comparison with rectangular formula design.
In fig. 7 and 8, the image sensor includes three photodiodes, a first photodiode, a second photodiode, and a third photodiode, and the corresponding capacitances 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, surrounding the display area AA, of the display panel, each of the light sensing diodes in each of the image sensors is provided with a bias power line in one-to-one correspondence, and a first end of the light sensing diode in each of the image sensors is connected with the corresponding bias power line. Alternatively, the plurality of image sensors distribute 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 stage, the reset module 11 is controlled to be conducted by inputting a reset signal to the Vrst end of the reset signal so as to reset the control end of the amplifying module 12;
in the exposure stage, the input of the reset signal to the reset signal terminal is stopped to cut off the reset module 11, and a signal is provided to the bias power supply module (i.e., each bias power supply terminal) 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 supplying a data read signal to the signal read terminal Vread.
The magnitude of the capacitance in the photoelectric conversion module can be adjusted by presetting each bias power supply, so that the maximization of the gain is realized when the minimization of the capacitance is realized, the signal-to-noise ratio is improved, and the photosensitivity of the image sensor is ensured; the resistance of the image sensor to strong light can also be improved with the maximization of capacitance.
The above description is only illustrative of the preferred embodiments of the present invention and of the principles of the technology employed. It will be appreciated by persons skilled in the art that the scope of the invention referred to in the present invention is not limited to the specific combinations of the technical features described above, but also covers other technical features formed by any combination of the technical features described above or their equivalents without departing from the inventive concept. Such as the above-mentioned features and the technical features disclosed in the present invention (but not limited to) having similar functions are replaced with each other.
Claims (9)
1. The image sensor is characterized by comprising a reset module, an amplifying 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 module, and the second end of the reset module is connected with the control end of the amplifying module;
the first end of the amplifying module is connected with the second power module, and the second end of the amplifying module is connected with the first end of the reading module;
the photoelectric conversion module includes: the bias power supply module comprises at least two bias power supply ends, a first end of each of the light sensing diodes is connected with one bias power supply end, at least two light sensing diodes are respectively connected with two different bias power supply ends, and a second end of each of the light sensing diodes is connected with a control end of the amplifying 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 amplifying 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 amplifying module is reset, and transmitting the electric signal to the control end of the amplifying module;
the amplifying module is used for transmitting the electric signal to the first end of the reading module in a conducting state;
the reading module is used for transmitting the electric signal to the signal output end under the control of the signal reading end.
2. The image sensor of claim 1, wherein each bias power supply terminal of the bias power supply module corresponds to each light sensing diode of the photoelectric conversion module one by one.
3. 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 first transistor is a second terminal of the reset module.
4. The image sensor of claim 1, wherein the amplification module comprises a second transistor, a control terminal of the second transistor being a control terminal of the amplification module, a first terminal of the second transistor being a first terminal of the amplification module, a second terminal of the second transistor being a second terminal of the amplification module.
5. The image sensor of claim 1, wherein the read module comprises a third transistor, a control terminal of the third transistor being a control terminal of the read module, a first terminal of the third transistor being a first terminal of the read module, a second terminal of the third transistor being a second terminal of the read module.
6. The image sensor according to any one of claims 1 to 5, wherein the image sensor includes a substrate board, a circuit layer, and a photosensitive device functional layer, which are sequentially stacked, the reset module, the amplification module, and the read module being disposed in the circuit layer, and the photoelectric conversion module being disposed in the photosensitive device functional layer;
the photosensitive device functional layer comprises at least two photosensitive diodes, and orthographic projections of the at least two photosensitive diodes on the substrate base plate are of a structure which is sleeved in sequence from inside to outside and distributed at intervals.
7. The image sensor of claim 6, wherein orthographic projections of the photosensitive diode positioned at the center of the photosensitive device functional layer on the substrate are in an elliptical structure, and orthographic projections of the rest of the photosensitive diodes on the substrate are in an elliptical ring structure;
or, orthographic projection of the photosensitive diode positioned in the center of the photosensitive device functional layer on the substrate is in a circular structure, and orthographic projections of the rest photosensitive diodes on the substrate are in a circular structure;
or, the orthographic projection of the photosensitive diode positioned in the center of the photosensitive device functional layer on the substrate is in a rectangular structure, and the orthographic projections of the rest of photosensitive diodes on the substrate are in a rectangular annular structure.
8. A display panel comprising a plurality of image sensors as claimed in any one of claims 1-7.
9. A control method of an image sensor, characterized by being applied to the image sensor according to any one of claims 1 to 7; the control method comprises the following steps:
and (3) a reset stage: the reset module is controlled to be conducted by inputting a reset signal to the reset signal end so as to reset the control end of the amplifying module;
exposure stage: stopping inputting a reset signal to the reset signal end to enable the reset module to be closed, and controlling the gain-adjustable photoelectric conversion module to convert the optical signal into an electric signal by inputting a bias signal to the bias power supply module;
reading: and the reading module is controlled to be conducted to read out the electric signal by providing a data reading signal to the signal reading end.
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