CN118111557A

CN118111557A - Photoelectric sensing circuit and display device

Info

Publication number: CN118111557A
Application number: CN202410232608.0A
Authority: CN
Inventors: 解红军
Original assignee: Yungu Guan Technology Co Ltd
Current assignee: Yungu Guan Technology Co Ltd
Priority date: 2024-02-29
Filing date: 2024-02-29
Publication date: 2024-05-31

Abstract

The application provides a photoelectric sensing circuit and a display device; the photoelectric sensing circuit comprises a photoelectric sensing module and a replacement module, wherein the photoelectric sensing module comprises a photoelectric sensing unit and a first coupling unit, and the first coupling unit is provided with a storage node, and the storage node comprises: the photoelectric sensing unit is connected with the storage node and is configured to enable the storage node to have a corresponding photo-generated potential according to the received optical signal; the first coupling unit is connected with the sensing signal line and is configured to respond to the effective potential of the first control signal, so that the reference potential on the sensing signal line is written into the storage node to couple the photo-generated potential to the replacement module; the replacement module is connected with the sensing signal line and is configured to output a sensing voltage related to the photo-generated potential and the reference potential. In this way, the recognizability and accuracy of the sensing voltage are ensured.

Description

Photoelectric sensing circuit and display device

Technical Field

The application relates to the technical field of display, in particular to a photoelectric sensing circuit and a display device.

Background

With the development of display technology, an Active Matrix Organic Light Emitting Diode (AMOLED) display module has shown great potential. However, in the existing display module, there is still a problem that the sensing result is difficult to be identified when the optical signal is sensed.

Disclosure of Invention

In view of the above, the present application is directed to providing a photoelectric sensing circuit and a display device capable of ensuring the identifiability of a photoelectric sensing result.

In a first aspect, the present application provides an optoelectronic sensing circuit comprising at least an optoelectronic sensing module and a replacement module, the optoelectronic sensing module comprising an optoelectronic sensing unit and a first coupling unit, the first coupling unit having a storage node, wherein:

The photoelectric sensing unit is connected with the storage node and is configured to enable the storage node to have a corresponding photo-generated potential according to the received optical signal;

The first coupling unit is connected with the sensing signal line and is configured to respond to the effective potential of a first control signal, so that the reference potential on the sensing signal line is written into the storage node to couple the photo-generated potential to the replacement module;

The replacement module is connected to the sensing signal line and configured to output a sensing voltage related to the photo-generated potential and the reference potential.

Alternatively, the process may be carried out in a single-stage,

The reference potential is not less than 0; or alternatively

The photoelectric sensing module has a preset characteristic value, the preset characteristic value is smaller than 0, the first coupling unit has a first dielectric constant, the replacement module has a second dielectric constant, wherein the sum of the first dielectric constant and the second dielectric constant has a first product with the reference potential, the first dielectric constant and the preset characteristic value have a second product, and the first product is larger than the second product;

Preferably, the second dielectric constant is smaller than the first dielectric constant.

Optionally, the optoelectronic sensing module further comprises an initialization unit, wherein:

The initialization unit is connected with an initialization signal line and the storage node, and is configured to write an initialization voltage on the initialization signal line into the storage node in response to an effective potential of a second control signal when the first control signal is at a failure potential;

Preferably, the photoelectric sensing unit has an on voltage and is connected with a first power line, the first power line is configured with a first fixed voltage, and the difference between the first fixed voltage and the initialization voltage is greater than the absolute value of the on voltage;

preferably, the photoelectric sensing unit is configured to cause the storage node to have the photo-generated potential when the first control signal is at a failure potential and the second control signal is at a failure potential;

preferably, the initializing unit includes a first transistor, a control electrode of the first transistor is configured with the second control signal, a first electrode of the first transistor is connected to the initializing signal line, and a second electrode of the first transistor is connected to the storage node.

Optionally, the replacement module includes an operational amplifier unit, a second coupling unit, and a switch unit, where:

The operational amplifier unit comprises an in-phase input end, an anti-phase input end and an output end, wherein the in-phase input end is connected with a reference signal line, the reference signal line is configured with the reference potential, the anti-phase input end is connected with one end of the second coupling unit, one end of the switch unit and the sensing signal line, and the output end is connected with the other end of the second coupling unit and the other end of the switch unit;

preferably, the switching unit is configured to write the reference potential of the non-inverting input terminal to the sensing signal line in response to an effective potential of a third control signal when the first control signal is at an effective potential, and configured to output the sensing voltage to the output terminal in response to the effective potential of the third control signal when the first control signal is at the effective potential.

Optionally, the photoelectric sensing circuit further comprises a sampling module, wherein:

the sampling module is connected with the output end of the operational amplifier unit and is configured to respond to the effective potential of the sampling signal to sample the sensing voltage at the output end when the first control signal is at the effective potential;

Preferably, after the first control signal is at an effective potential for a first time, the sampling signal is at an effective potential, and after the sampling signal is at a dead potential for a second time, the first time is greater than the second time;

Preferably, the second time is 0.

Optionally, the first coupling unit includes a first capacitor and a second transistor, wherein:

The control electrode of the second transistor is configured with the first control signal, the first electrode of the second transistor and the first end of the first capacitor are both connected to the storage node, and the second electrode of the second transistor is connected to the sensing signal line; the second end of the first capacitor is connected with the initialization signal line.

In a second aspect, the present application provides a display device comprising a photo-sensing circuit according to the first aspect of the application.

Optionally, the display device includes a display panel and a driving chip, wherein:

the photoelectric sensing module and the sensing signal line of the photoelectric sensing circuit are arranged in the display panel;

the replacement module of the photoelectric sensing circuit is arranged in the driving chip.

Optionally, the photoelectric sensing circuit includes a plurality of the photoelectric sensing modules arranged in an array in a first direction and a second direction, the first direction and the second direction have an included angle, the display panel includes a plurality of the sensing signal lines, the photoelectric sensing circuit includes a plurality of the replacement modules, wherein:

The same sensing signal line is connected with a plurality of photoelectric sensing modules and corresponding replacement modules which are arranged in the first direction;

Preferably, the first control signals corresponding to the photoelectric sensing modules connected to the same sensing signal line are respectively at effective potentials at different times;

Preferably, a plurality of the sensing signal lines are arranged along the second direction;

Preferably, the display panel further includes a light emitting unit, and the cathode of the photo sensing unit and the cathode of the light emitting unit are connected with a first power line configured with a first fixed voltage.

Optionally, the optoelectronic sensing module further includes an initializing unit connected to an initializing signal line and the storage node, and configured to write an initializing voltage on the initializing signal line into the storage node in response to an active potential of a second control signal when the first control signal is at a failure potential, wherein:

The second control signals corresponding to the photoelectric sensing modules connected with the same sensing signal line are respectively at effective potentials at different moments.

In the scheme of the application, the photoelectric sensing circuit comprises a photoelectric sensing module and a replacement module; the photo-sensing module comprises a photo-sensing unit and a first coupling unit, the first coupling unit having a storage node, wherein: the photoelectric sensing unit is connected with the storage node and is configured to enable the storage node to have a corresponding photo-generated potential according to the received optical signal; the first coupling unit is connected with the sensing signal line and is configured to respond to the effective potential of the first control signal, so that the reference potential on the sensing signal line is written into the storage node to couple the photo-generated potential to the replacement module; the replacement module is connected with the sensing signal line and is configured to output a sensing voltage related to the photo-generated potential and the reference potential. Therefore, the current type photoelectric sensing circuit is constructed, the photoelectric sensing module can sense optical signals to obtain photo-generated potential, and based on reference potential, the photo-generated potential in the storage node is replaced by the replacement module to obtain sensing voltage, so that the condition that the sensing voltage is difficult to identify due to negative pressure is avoided, and the identifiability and accuracy of the sensing voltage are ensured.

Drawings

The above and other objects, features and advantages of the present application will become more apparent by describing embodiments of the present application in more detail with reference to the attached drawings. The accompanying drawings are included to provide a further understanding of embodiments of the application and are incorporated in and constitute a part of this specification, illustrate the application and together with the embodiments of the application, and not constitute a limitation to the application. In the drawings, like reference numerals generally refer to like parts or steps.

FIG. 1 is a schematic diagram of a photoelectric sensing circuit according to an embodiment of the present application;

FIG. 2 is a schematic diagram of another photoelectric sensing circuit according to an embodiment of the present application;

FIG. 3 is a schematic diagram of a photo sensor circuit according to another embodiment of the present application;

FIG. 4 is a schematic diagram of a photo sensor circuit according to another embodiment of the present application;

FIG. 5 is a schematic diagram of a photo sensor circuit according to another embodiment of the present application;

FIG. 6 is a schematic diagram of a photo sensor circuit according to another embodiment of the present application;

FIG. 7 is a schematic diagram of timing control of a photo sensor circuit according to an embodiment of the present application;

FIG. 8 is a flow chart of a fingerprint sensing method according to an embodiment of the present application;

fig. 9 is a schematic structural diagram of a display module according to an embodiment of the application.

Detailed Description

Unless defined otherwise, technical or scientific terms used in the embodiments of the present specification should be given the ordinary meaning as understood by one of ordinary skill in the art to which the present specification belongs. The terms "first," "second," and the like, as used in the embodiments of the present disclosure, do not denote any order, quantity, or importance, but rather are used to avoid intermixing of the components.

Throughout the specification, unless the context requires otherwise, the word "plurality" means "at least two", and the word "comprising" is to be construed as open, inclusive meaning, i.e. as "comprising, but not limited to. In the description of the present specification, the terms "one embodiment," "some embodiments," "example embodiments," "examples," "particular examples," or "some examples," etc., are intended to indicate that a particular feature, structure, material, or characteristic associated with the embodiment or example is included in at least one embodiment or example of the present specification. The schematic representations of the above terms do not necessarily refer to the same embodiment or example.

The technical solutions of the embodiments of the present specification will be clearly and completely described below with reference to the drawings in the embodiments of the present specification, and it is apparent that the described embodiments are only some embodiments of the present specification, not all embodiments. All other embodiments, which can be made by one of ordinary skill in the art without undue burden from the present disclosure, are intended to be within the scope of the present disclosure.

With the rise of the concept of full-screen, the development of photoelectric sensing technology is receiving attention. Among them, how to ensure that the photoelectric sensing signal is accurately identified is needed to be solved.

For example, in a fingerprint recognition module of an Active Matrix Organic Light Emitting Diode (AMOLED) display module, photocurrent generated by an organic photodiode (Organic Photo Diode, OPD) device is reverse, and when the active matrix organic light emitting Diode (Active Matrix Organic LIGHT EMITTING Diode) display module is integrated in an AMOLED display screen, the OPD device and the AMOLED share a power supply, which results in that when the OPD device is used for fingerprint sensing, a sensing signal is a negative pressure signal, and many fingerprint sensing chips are all positive pressure sensing, the negative pressure signal enters the fingerprint sensing chip, so that a situation that the fingerprint sensing chip cannot cope with occurs, that is, the fingerprint sensing chip in the AMOLED display module cannot accurately recognize the sensing signal generated by the fingerprint sensing.

Therefore, the application provides a scheme for conveniently and accurately identifying the sensing signal, a novel current type photoelectric sensing circuit is constructed, the photo-generated potential can be generated by sensing the optical signal, the photo-generated potential is replaced by the reference potential in the form of current based on the law of conservation of charge, and the forward sensing voltage can be obtained by calculating the voltage generated by replacing the current. Therefore, the sensing chip can be prevented from being trouble that the sensing signal is negative pressure and cannot be handled, feasibility of a sensing scheme is improved, and identifiability and accuracy of sensing voltage are ensured.

Specifically, as an optional implementation of the disclosure, an embodiment of the present application provides an optoelectronic sensing circuit. Fig. 1 is a schematic structural diagram of an optoelectronic sensing circuit according to an embodiment of the present application, and fig. 2 is another schematic structural diagram of an optoelectronic sensing circuit according to an embodiment of the present application, where, as shown in fig. 1 and fig. 2, the optoelectronic sensing circuit may at least include: a photoelectric sensing module A1 and a replacement module A2.

The photo sensing module A1 may include a photo sensing unit a11 and a first coupling unit a12. The first coupling unit a12 has a storage node An, wherein the photo sensing unit a11 is connected to the storage node An and configured to cause the storage node An to have a corresponding photo-generated potential according to the received optical signal.

The first coupling unit a12 is connected to the sensing signal line S and configured to write the reference potential V _REF on the sensing signal line S to the storage node An in response to the active potential of the first control signal RD to couple the photo-generated potential to the permutation module A2.

The replacement module A2 is connected to the sensing signal line S and configured to output a sensing voltage V _out related to the photo-generated potential and the reference potential V _REF.

Specifically, in the photoelectric sensing module A1, the photoelectric sensing unit a11 may be used to sense An optical signal, so as to obtain the photo-generated potential V _An and write the photo-generated potential V _An into the storage node An. Further, by using the first coupling unit a12, when the first coupling unit responds to the effective potential of the first control signal RD, the reference potential V _REF on the sensing signal line S is also written into the storage node An, the potential in the storage node An is changed from the photo-generated potential to the reference potential, meanwhile, part of the charge in the storage node An is transferred to the replacement module A2, and because the replacement module A2 is connected with the sensing signal line S, that is, the replacement module A2 can receive the reference potential V _REF, the replacement module A2 can obtain the forward sensing voltage V _out by using the charge transferred to the replacement module A2 and the reference potential V _REF provided to the replacement module A2 by the sensing signal line S based on the law of conservation of charge, that is, the sensing voltage V _out related to the photo-generated potential and the reference potential V _REF is output. Therefore, the condition that the sensing voltage is negative is avoided, and the identifiability of the photoelectric sensing result is ensured.

In some embodiments, as shown in fig. 3, the replacement module A2 may include an operational amplifier unit a21, a second coupling unit a22, and a switching unit a23, where: the operational amplifier unit a21 may include an in-phase input terminal connected with the reference signal line B configured with the reference potential V _REF, an inverting input terminal connected with one end of the second coupling unit a22, one end of the switching unit a23, and the sensing signal line S, and an output terminal connected with the other end of the second coupling unit a22 and the other end of the switching unit a 23.

As shown in fig. 4, the second coupling unit a22 may include a second capacitor C2.

The switching unit a23 may include a third transistor T3, a control electrode of the third transistor T3 is configured with a third control signal SW, a first electrode of the third transistor T3 is connected to an inverting input terminal of the operational amplifier unit a21, and a second electrode of the third transistor T3 is connected to an output terminal Vout of the operational amplifier unit a 21. Wherein the third transistor T3 is turned on in response to the active potential of the third control signal SW and turned off in response to the inactive potential of the third control signal SW.

Preferably, the switching unit a23 is configured to write the reference potential V _REF at the non-inverting input terminal into the sensing signal line S in response to the active potential of the third control signal SW when the first control signal RD is at the inactive potential, that is, the non-inverting input of the substitution module A2 is equal to the output, thereby implementing the buffer function of the substitution module A2; and, the switch unit a23 is configured to, when the first control signal RD is at an active potential, cause the output terminal Vout to output the sensing voltage in response to the failure potential of the third control signal SW, thereby implementing the integrating function of the substitution module A2.

In some embodiments, the reference potential V _REF may be set to be not less than 0.

It should be noted that, in the sensing stage, the output end of the replacement module A2 starts integration based on the reference potential V _REF, that is, the sensing voltage output by the replacement module A2 is the minimum reference potential, so that setting the reference potential V _REF to be not less than 0 can ensure that the sensing voltage output by the replacement module A2 is positive, thereby ensuring the identifiability of the driving chip to the sensing voltage during application.

Or the photoelectric sensing module A1 may be set to have a preset characteristic value, the preset characteristic value is smaller than 0, the first coupling unit a12 has a first dielectric constant, the replacement module A2 has a second dielectric constant, wherein a sum of the first dielectric constant and the second dielectric constant has a first product with the reference potential V _REF, the first dielectric constant has a second product with the preset characteristic value, and the first product is larger than the second product.

In practice, the preset characteristic value is smaller than 0, that is, the preset characteristic value is a negative value, and the specific numerical value can be selected according to the magnitude of the photo-generated potential in practical application. When the method is applied, a value closest to 0 can be selected from empirical data of the photo-generated potential to serve as a preset characteristic value.

Preferably, the second dielectric constant is less than the first dielectric constant. In this way, the change amplitude of the sensing voltage output by the replacement module A2 is larger under the same charge transfer amount.

In some embodiments, as shown in fig. 2, the photoelectric sensing module A1 may further include an initialization unit a13, where: the initialization unit a13 is connected to the initialization signal line L and the storage node An, and is configured to write the initialization voltage Vini on the initialization signal line L into the storage node An in response to the active potential of the second control signal RST when the first control signal RD is at the failure potential.

With the initializing unit a13, when the first control signal RD is at the failure potential, the initializing voltage Vini transmitted by the initializing signal line L can be written into the storage node An, so that the voltage of the storage node An becomes the initializing voltage Vini, thereby realizing the initializing process of the storage node An.

After initializing the storage node An, the photo-sensing unit a11 can be used to sense the photo-signal, so that the storage node An has a corresponding photo-generated potential, and further provides the effective potential of the first control signal RD to the first coupling unit a12, so that the reference potential V _REF on the sensing signal line S is written into the storage node An to couple the photo-generated potential to the replacement module A2.

In practice, as shown in fig. 2, the photo sensing unit a11 may further have an on voltage and be connected to a first power line P, where the first power line P is configured with a first fixed voltage ELVSS.

The photo sensing unit a11 may include An organic photodiode D, and when the photo sensing unit a11 is implemented, an on voltage of the organic photodiode D, that is, an on voltage of the organic photodiode D, an anode terminal of the organic photodiode D is connected to the storage node An, and a cathode terminal of the organic photodiode D is connected to the first power line P.

In order to ensure that the organic photodiode D can generate photo-generated current under the action of light, the voltage difference between the first fixed voltage ELVSS and the storage node An is greater than the start-up voltage, and since the voltage of the storage node An is the initialization voltage Vini after the initialization process is performed on the storage node An, the relationship among the start-up voltage Vth, the first fixed voltage ELVSS and the initialization voltage Vini is as follows:

Vini＜ELVSS-|Vth|

In some embodiments, the photo sensing unit a11 is configured to make the storage node An have a photo-generated potential when the first control signal RD is at the failure potential and the second control signal RST is at the failure potential.

Specifically, when the first control signal RD is at the failure potential, the sensing signal line S and the storage node An are in An off state, that is, the storage node An cannot receive the reference potential V _REF; similarly, when the second control signal RST is at the failure potential, the initialization signal line L and the storage node An are also in An off state, that is, the storage node An cannot receive the initialization voltage Vini, and at this time, the organic photodiode D generates a corresponding photo-generated current according to the optical signal, and the photo-generated current causes the storage node An to generate a corresponding photo-generated potential.

In implementation, the initialization unit a13 may include a first transistor T1, a control electrode of the first transistor T1 is configured with a second control signal RST, a first electrode of the first transistor T1 is connected to the initialization signal line L, and a second electrode of the first transistor T1 is connected to the storage node An.

When the second control signal RST received by the control electrode of the first transistor T1 is at An effective potential, the first transistor T1 is in a conducting state, that is, is conducted between the initialization signal line L and the storage node An, and the initialization voltage Vini is written into the storage node An; when the second control signal RST received by the control electrode of the first transistor T1 is at the failure potential, the first transistor T1 is in An off state, that is, the initialization signal line L is disconnected from the storage node An, and the initialization voltage Vini stops writing into the storage node An.

In some embodiments, as shown in fig. 2, the first coupling unit a12 may include a first capacitor C1 and a second transistor T2, wherein: the control electrode of the second transistor T2 is configured with a first control signal RD, the first electrode of the second transistor T2 and the first end of the first capacitor C1 are both connected to the storage node An, and the second electrode of the second transistor T2 is connected to the sensing signal line S; the second terminal of the first capacitor C1 is connected to the initialization signal line L.

When the first control signal RD received by the control electrode of the second transistor T2 is in An effective potential, the second transistor T2 is in a conducting state, namely, a sensing signal line S is conducted with a storage node An, and a reference potential V _REF is written into the storage node An; when the first control signal RD received by the control electrode of the second transistor T2 is at the failure potential, the second transistor T2 is in An off state, that is, the sense signal line S is disconnected from the storage node An, and the reference potential V _REF stops writing into the storage node An.

It should be understood that when the voltage of the storage node An is the initialization voltage Vini, the voltage difference across the first capacitor C1 is 0V, that is, after the initialization process is performed on the storage node An, the voltage difference across the first capacitor is 0V.

In specific implementation, the working process of the photoelectric sensing circuit may sequentially include an initialization phase t1, a charging phase t2 and a sensing phase t3.

In the initialization phase T1, the first transistor T1 is turned on in response to the effective potential of the second control signal RST, the second transistor T2 is turned off in response to the failure potential of the first control signal RD, the initialization voltage Vini output by the initialization signal line L is written into the storage node An, the voltage difference across the first capacitor C1 becomes 0, and at the same time, the third transistor T3 is turned on in response to the effective potential of the third control signal SW, the op-amp unit a21 is used as a buffer circuit, and the reference potential V _REF at the non-inverting input terminal thereof is written into the sensing signal line S, such that the sensing signal line S has the reference potential V _REF.

In the charging stage T2, the first transistor T1 is turned off in response to the failure potential of the second control signal RST, the second transistor T2 is turned off in response to the failure potential of the first control signal RD, the organic photodiode D generates a photo-generated current after receiving the optical signal, and the photo-generated current charges the storage node An and the first capacitor C1, so that the potential of the storage node An gradually rises to have a corresponding photo-generated potential, and meanwhile, the third transistor T3 is still in a conductive state in response to the effective potential of the third control signal SW.

In the sensing phase T3, the first transistor T1 is turned off in response to the failure potential of the second control signal RST, the second transistor T2 is turned on in response to the effective potential of the first control signal RD, the reference potential V _REF is written into the storage node An, the potential of the storage node An is changed from the photo-generated potential to the reference potential V _REF, meanwhile, the third transistor T3 is turned off in response to the failure potential of the third control signal SW, the replacement module A2 is turned off as An integrator, the redundant charge of the first capacitor C1 enters the replacement module A2 through the second transistor T2 and the sensing signal line S, and the voltage of the output terminal V _out of the operational amplifier unit a21 is changed and gradually becomes stable. During the integration process, the reference potential V _REF of the sensing signal line S is constant.

In some embodiments, as shown in fig. 4, the photo-sensing circuit may further include a sampling module A3, wherein: the sampling module A3 is connected to the output terminal Vout of the operational amplifier unit a21, and is configured to sample the sensing voltage at the output terminal Vout in response to the effective potential of the sampling signal SMP when the first control signal RD is at the effective potential.

The sampling module A3 may include a fourth transistor, where a control electrode of the fourth transistor is configured with a sampling signal SMP, a first electrode of the fourth transistor is connected to the output terminal Vout of the operational amplifier unit a21, and a second electrode of the fourth transistor is an output terminal of the photo-sensing circuit. In practice, the fourth transistor is turned on in response to the active potential of the sampling signal SMP and turned off in response to the inactive potential of the sampling signal.

In some embodiments, the sampling signal SMP is at an active potential after the first control signal RD is at an active potential for a first time, and the first control signal RD is at an inactive potential after the sampling signal SMP is at an inactive potential for a second time, wherein the first time is greater than the second time.

Taking the second transistor as an N-type transistor as an example, as shown in fig. 5, in the initialization stage T1 and the charging stage T2, the second control signal RD is a low level signal (failure potential), and at this time, the second transistor T2 is in an off state in response to the failure potential of the first control signal RD, the replacement module A2 operates as a buffer circuit, and the potential of the sensing signal line S is at the reference potential V _REF. At the end instant of the charging phase T2, the first control signal RD changes from a low level signal to a high level signal (active potential), the second transistor T2 changes from an off state to an on state in response to the active potential of the first control signal RD, and the replacement module A2 starts to perform the integrator function.

That is, in the sensing stage T3, the replacement module A2 starts integrating, the charge transferred by the first capacitor C1 enters the inverting input terminal of the op-amp unit a21 through the second transistor T2 and the sensing signal line S, and the voltage at the output terminal of the op-amp unit a21 starts to change. During the integration process, the potential of the sensing signal line S is unchanged and constant to the reference potential V _REF. When the sensing phase t3 is about to end, that is, after the first time when the first control signal RD is at the active potential, the sampling signal SMP is at the active potential, and the sampling module A3 samples the sensing voltage at the output terminal Vout of the op-amp unit a 21. And, after the sampling signal SMP is at the failure potential for the second time, the first control signal RD is at the failure potential.

In practice, the sensed voltage is related to the photo-generated potential and the reference potential, so that the photo-generated potential can be calculated according to the sensed voltage obtained by sampling and the determined reference potential.

Specifically, the calculation formula of the photo-generated potential V _An may include:

Wherein C ₂ is an integrating capacitor (second capacitor) of the op-amp unit, C ₁ is a first capacitor, V _out is an output voltage (sensing voltage) of the output end of the op-amp unit a21, and V _REF is a reference potential.

The voltage of the first capacitor C1 after the end of the charging period t2 can be calculated by using a calculation formula of the photo-generated potential, thereby obtaining the anode potential of the organic photodiode D. The photoelectric sensing circuit is applied to the display device, so that fingerprint identification of a corresponding fingerprint identification area in the display device can be realized.

It should be appreciated that setting the first time to be greater than the second time, i.e. setting the sampling time in a period of time that is about to end the sensing phase, may ensure that there is sufficient integration time during integration, thereby ensuring that a more accurate sensed voltage is obtained.

Specifically, the first time may be set according to actual requirements, for example, the first time may be set to 0.1 seconds before the sensing phase ends.

Preferably, the second time may be set to 0. The second time is 0, that is, the sampling time is set in the last time period of the sensing phase, so that enough integration time can be provided for the integration process, and the accuracy and reliability of the acquired sensing voltage are further improved.

As an alternative implementation of the present disclosure, an embodiment of the present disclosure further provides a display device, where the display device is shown in fig. 6. Wherein the display device may comprise a photo-sensing circuit as described in any of the embodiments above.

Specifically, the display device may further include a display panel and a driving chip, wherein: the photoelectric sensing module A1 and the sensing signal line S of the photoelectric sensing circuit are arranged in the display panel; the replacement module A2 of the photoelectric sensing circuit is arranged in the driving chip.

In the embodiment of the application, the photoelectric sensing module A1 and the sensing signal line S of the photoelectric sensing circuit are arranged in the display panel, and the replacement module A2 of the photoelectric sensing circuit is arranged in the driving chip, so that the fingerprint identification technology of the display device can be realized by utilizing the photoelectric sensing circuit, and the identification accuracy can be improved.

When the fingerprint sensing circuit is applied, the photoelectric sensing module A1 of the photoelectric sensing circuit can convert an optical signal reflected by a fingerprint into an electric signal in the fingerprint sensing process, and based on the law of conservation of charge, partial charges stored in the fingerprint sensing process are transferred into the replacement module A2 by using the replacement module A2 through the reference potential V _REF provided by the sensing signal line S, so that the fingerprint sensing voltage is obtained.

In some embodiments, as shown in fig. 7, the photoelectric sensing circuit may include a plurality of photoelectric sensing modules A1 arranged in an array in a first direction X and a second direction Y, where the first direction X and the second direction Y have an included angle, the display panel includes a plurality of sensing signal lines S, and the photoelectric sensing circuit includes a plurality of replacement modules A2, where: the same sensing signal line S connects a plurality of photo-sensing modules A1 arranged in the first direction and corresponding replacement modules A2.

Thus, the photo-sensor module A1 located in the same second direction Y receives the same reference voltage V _REF and the same initialization voltage Vini at the same time. That is, the timing control of the photo-sensing modules A1 located in the same second direction Y is the same, and the photo-sensing modules A1 located in the same second direction Y undergo the initialization phase, the charging phase and the sensing phase at the same time.

In implementation, the first direction X may be a column direction, the second direction Y may be a row direction, the photo-sensing modules A1 located in the same row receive the same first control signal RD and the second control signal RST at the same time, and the photo-sensing modules A1 located in the same column are connected to the same sensing signal line S, so that the photo-sensing process may be performed in a progressive scanning manner, that is, the second control signal RST and the first control signal RD are opened row by row, and the photo-sensing modules A1 in different rows do not interfere with each other. Meanwhile, the photoelectric sensing modules A1 positioned in the same column share the same replacement module A2, and the photoelectric sensing modules A1 in different columns do not interfere with each other, so that the order and the synchronism of sensing voltage acquisition among the photoelectric sensing modules A1 positioned in the same row in the progressive scanning process are ensured while the photoelectric sensing area is increased and the accuracy of photoelectric sensing is improved.

Taking the collection of fingerprint information as an example, in order to collect the fingerprint information of each region in the fingerprint to be identified, a plurality of photoelectric sensing modules A1 are arranged in an array. Each photoelectric sensing module A1 is provided with a corresponding fingerprint sensing area, and the photoelectric sensing modules A1 sense fingerprint information in the corresponding fingerprint sensing areas, so that a plurality of photoelectric sensing modules A1 sense complete fingerprint identification areas, and complete fingerprint identification information is obtained.

In some embodiments, the first control signals corresponding to the photo-sensor modules A1 connected to the same sensing signal line S are respectively at the effective potential at different times. That is, the effective potentials of the first control signals can be supplied one by one along the extending direction of the same sensing signal line S, so that interference between the respective photo-sensing modules A1 on the same sensing signal line S can be avoided.

In implementation, the plurality of sensing signal lines S may be arranged along the second direction Y, so that the photoelectric sensing modules A1 located in the same second direction Y may be connected to the same sensing signal line S, thereby simplifying wiring resources.

Preferably, the display panel may further include a light emitting unit, and the cathode of the photo sensing unit a11 and the cathode of the light emitting unit are connected to a first power line P configured with a first fixed voltage ELVSS.

In practice, the first fixed voltage ELVSS may be a ground voltage.

In some embodiments, as shown in fig. 8, the photoelectric sensing module A1 may further include An initialization unit a13, where the initialization unit a13 is connected to the initialization signal line L and the storage node An, and is configured to, when the first control signal RD is at the failure potential, cause the initialization voltage Vini on the initialization signal line L to be written into the storage node An in response to the active potential of the second control signal RST, where: the second control signals RST corresponding to the photoelectric sensing modules A1 connected to the same sensing signal line S are respectively at the effective potential at different times.

In implementation, the second control signals corresponding to the photoelectric sensing modules A1 connected with the same sensing signal line S are set to be at effective potentials at different times, so that mutual interference among the photoelectric sensing modules A1 on the same sensing signal line S can be avoided, and orderly and effective performance of the photoelectric sensing process is ensured.

As shown in fig. 9, the photoelectric sensing circuit may further include a plurality of sampling modules A3, where the sampling modules A3 are also located inside the driving IC and disposed between the replacement module A2 and the driving chip IC.

In implementation, the driving chip IC may provide the sampling signal SMP to the corresponding sampling module A3 to collect the sensing voltage Vout, so as to determine the photo-generated potential generated by the optical signal.

In practical application, the display module provided by the embodiment of the application can be applied to a smart phone, a tablet personal computer or a digital camera and the like, and is not repeated here.

In the present specification, each embodiment is described in a progressive manner, and each embodiment is mainly described in a different point from other embodiments, and identical and similar parts between the embodiments are all enough to refer to each other.

The previous description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the present application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the application. Thus, the present application is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A photo-electric sensing circuit comprising at least a photo-electric sensing module and a replacement module, the photo-electric sensing module comprising a photo-electric sensing unit and a first coupling unit, the first coupling unit having a storage node, wherein:

2. The optoelectronic sensing circuit of claim 1, wherein,

The reference potential is not less than 0; or alternatively

3. The optoelectronic sensing circuit of claim 1, wherein the optoelectronic sensing module further comprises an initialization unit, wherein:

4. The optoelectronic sensing circuit of claim 1, wherein the replacement module comprises an op-amp unit, a second coupling unit, and a switching unit, wherein:

5. The optoelectronic sensing circuit of claim 4, further comprising a sampling module, wherein:

Preferably, the second time is 0.

6. A photo-sensing circuit according to claim 3, wherein the first coupling unit comprises a first capacitor and a second transistor, wherein:

7. A display device comprising a photo-sensing circuit as claimed in any one of claims 1 to 6.

8. The display device of claim 7, comprising a display panel and a driver chip, wherein:

The photoelectric sensing module and the sensing signal line in the photoelectric sensing circuit are arranged in the display panel;

The replacement module in the photoelectric sensing circuit is arranged in the driving chip.

9. The display device according to claim 8, wherein the photo-sensing circuit includes a plurality of the photo-sensing modules arrayed in a first direction and a second direction, the first direction and the second direction having an included angle, the display panel includes a plurality of the sensing signal lines, the photo-sensing circuit includes a plurality of the replacement modules, wherein:

10. The display device according to claim 8, wherein the photoelectric sensing module further comprises an initializing unit connected to an initializing signal line and the storage node, and configured to write an initializing voltage on the initializing signal line to the storage node in response to an active potential of a second control signal when the first control signal is at a failure potential, wherein: