A photoelectric detection circuit and display device

Abstract

The application provides a photoelectric detection circuit and a display device. The photoelectric detection circuit is provided with an auxiliary light sensing transistor in the same light environment condition as a main light sensing transistor. The threshold voltage of the auxiliary light sensing transistor is captured and compensated to the gate of the main light sensing transistor through a first threshold capturing compensation unit. Thus, the influence of the threshold voltage offset of the main light sensing transistor on the photoelectric signal generated by the main light sensing transistor is reduced, the photoelectric signal output by the main light sensing transistor due to characteristic drift is improved, and the detection precision of the photoelectric detection circuit is improved.

Description

Technical Field

[0001] This invention relates to the field of photoelectric detection technology, and more specifically, to a photoelectric detection circuit and display device. Background Technology

[0002] Currently, photoelectric detection circuits in existing display devices generally employ phototransistors that convert light intensity into photoelectric signals, connected to an analysis and processing circuit. The phototransistor generates a photoelectric signal output based on the light intensity, and the analysis and processing circuit then detects this signal to determine the current light intensity. However, existing phototransistors experience characteristic drift after prolonged exposure to light and the application of a DC bias voltage, leading to distortion of the photoelectric signal output and resulting in low detection accuracy. Summary of the Invention

[0003] In view of this, the present invention provides a photoelectric detection circuit and display device, which effectively solves the existing technical problems, improves the distortion of the output photoelectric signal caused by the characteristic drift of the main photosensitive transistor, and thus improves the detection accuracy of the photoelectric detection circuit.

[0004] To achieve the above objectives, the technical solution provided by the present invention is as follows:

[0005] A photoelectric detection circuit, comprising:

[0006] A main photosensitive transistor, wherein the first terminal of the main photosensitive transistor is electrically connected to a first fixed voltage terminal, and the second terminal of the main photosensitive transistor is used to output photoelectric signals;

[0007] An auxiliary photosensitive transistor, wherein the auxiliary photosensitive transistor and the main photosensitive transistor are both located under the same lighting environment conditions;

[0008] In addition, a first threshold grasping compensation unit is provided, which is electrically connected to both the main photosensitive transistor and the auxiliary photosensitive transistor. The first threshold grasping compensation unit is used to obtain the threshold voltage of the auxiliary photosensitive transistor and compensate the threshold voltage of the auxiliary photosensitive transistor to the gate of the main photosensitive transistor.

[0009] Accordingly, the present invention also provides a display device, which includes the above-described photoelectric detection circuit.

[0010] Compared with the prior art, the technical solution provided by the present invention has at least the following advantages:

[0011] This invention provides a photoelectric detection circuit and display device, comprising: a main photosensitive transistor, a first terminal of which is electrically connected to a first fixed voltage terminal, and a second terminal of which is used to output a photoelectric signal; an auxiliary photosensitive transistor, which is located under the same illumination environment as the main photosensitive transistor; and a first threshold capture compensation unit, which is electrically connected to both the main photosensitive transistor and the auxiliary photosensitive transistor, and is used to acquire the threshold voltage of the auxiliary photosensitive transistor and compensate the threshold voltage of the auxiliary photosensitive transistor to the gate of the main photosensitive transistor.

[0012] As can be seen from the above, the technical solution provided by the present invention includes an auxiliary phototransistor in the photoelectric detection circuit that is under the same lighting conditions as the main phototransistor. The threshold voltage of the auxiliary phototransistor is captured and compensated to the gate of the main phototransistor by the first threshold capture and compensation unit. This reduces the impact of the threshold voltage deviation of the main phototransistor on the generated photoelectric signal, improves the distortion of the output photoelectric signal caused by the characteristic drift of the main phototransistor, and thus improves the detection accuracy of the photoelectric detection circuit. Attached Figure Description

[0013] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0014] Figure 1 This is a schematic diagram of a photoelectric detection circuit provided in an embodiment of the present invention;

[0015] Figure 2 This is a schematic diagram of another photoelectric detection circuit provided in an embodiment of the present invention;

[0016] Figure 3 This is a schematic diagram of another photoelectric detection circuit provided in an embodiment of the present invention;

[0017] Figure 4 A timing diagram provided for an embodiment of the present invention;

[0018] Figure 5 This is a schematic diagram of another photoelectric detection circuit provided in an embodiment of the present invention;

[0019] Figure 6 This is a schematic diagram of another photoelectric detection circuit provided in an embodiment of the present invention;

[0020] Figure 7 This is a schematic diagram of another photoelectric detection circuit provided in an embodiment of the present invention;

[0021] Figure 8 This is a schematic diagram of another photoelectric detection circuit provided in an embodiment of the present invention;

[0022] Figure 9 This is a schematic diagram of another photoelectric detection circuit provided in an embodiment of the present invention;

[0023] Figure 10 This is a schematic diagram of another photoelectric detection circuit provided in an embodiment of the present invention;

[0024] Figure 11 This is a schematic diagram of another photoelectric detection circuit provided in an embodiment of the present invention;

[0025] Figure 12 This is a schematic diagram of another photoelectric detection circuit provided in an embodiment of the present invention;

[0026] Figure 13 This is a schematic diagram of the structure of a display device provided in an embodiment of the present invention. Detailed Implementation

[0027] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0028] As described in the background section, existing photoelectric detection circuits in display devices typically employ a phototransistor that converts light intensity into a photoelectric signal, connected to an analysis and processing circuit. The phototransistor generates a photoelectric signal output based on the light intensity, and the analysis and processing circuit then detects this signal to determine the current light intensity. However, existing phototransistors experience characteristic drift after prolonged exposure to light and the application of a DC bias voltage, resulting in distortion of the photoelectric signal output by the phototransistor and consequently, low detection accuracy in the photoelectric detection circuit.

[0029] Based on this, embodiments of the present invention provide a photoelectric detection circuit and a display device, which effectively solves the existing technical problems, improves the distortion of the output photoelectric signal caused by the characteristic drift of the main photosensitive transistor, and thus improves the detection accuracy of the photoelectric detection circuit.

[0030] To achieve the above objectives, the technical solutions provided by the embodiments of the present invention are as follows, in detail... Figures 1 to 13The technical solutions provided in the embodiments of the present invention will be described in detail.

[0031] refer to Figure 1 The diagram shown is a structural schematic of a photoelectric detection circuit provided in an embodiment of the present invention, wherein the photoelectric detection circuit includes:

[0032] The main photosensitive transistor M01 has its first terminal electrically connected to the first fixed voltage terminal V1, and its second terminal is used to output photoelectric signals to the signal detection unit 100 for analysis and processing.

[0033] An auxiliary photosensitive transistor M02 is provided, and both the auxiliary photosensitive transistor M02 and the main photosensitive transistor M01 are located under the same lighting conditions.

[0034] In addition, a first threshold grabbing compensation unit 210 is provided, which is electrically connected to both the main photosensitive transistor M01 and the auxiliary photosensitive transistor M02. The first threshold grabbing compensation unit 210 is used to obtain the threshold voltage of the auxiliary photosensitive transistor M02 and compensate the threshold voltage of the auxiliary photosensitive transistor M02 to the gate of the main photosensitive transistor M01.

[0035] Understandably, the technical solution provided in this embodiment of the invention includes an auxiliary phototransistor in the photoelectric detection circuit, which operates under the same illumination conditions as the main phototransistor, ensuring that the threshold voltage shift of the auxiliary phototransistor is consistent with that of the main phototransistor. Therefore, the threshold voltage of the auxiliary phototransistor is captured and compensated to the gate of the main phototransistor by the first threshold capture and compensation unit. During the process of the main phototransistor generating a photoelectric signal based on the illumination intensity (i.e., during the generation of a photoelectric current), the influence of the threshold voltage shift of the main phototransistor on the generated photoelectric signal is reduced, improving the distortion of the output photoelectric signal caused by characteristic drift of the main phototransistor, thereby enhancing the detection accuracy of the photoelectric detection circuit.

[0036] Furthermore, the auxiliary photosensitive transistor and the main photosensitive transistor provided in this embodiment of the invention have the same conduction type and the same fabrication structure and other parameters. That is, the threshold voltage of the auxiliary photosensitive transistor is the same as or differs from the threshold voltage of the main photosensitive transistor within an allowable small range, which can further reduce or even eliminate the influence of the shift in the threshold voltage of the main photosensitive transistor on the photoelectric signal it generates, thereby further improving the detection accuracy of the photoelectric detection circuit.

[0037] In one embodiment of the present invention, a first threshold capture compensation unit captures the threshold voltage of the auxiliary phototransistor and then transmits the threshold voltage to the gate of the phototransistor. This mitigates the impact of threshold voltage offset when the phototransistor generates a photoelectric signal, making the photoelectric signal generated by the phototransistor independent of its threshold voltage and improving the detection accuracy of the photoelectric detection circuit. (Reference) Figure 2 The diagram shown is a schematic diagram of another photoelectric detection circuit provided in an embodiment of the present invention. The first threshold grasping compensation unit provided in the embodiment of the present invention includes: a first charging module 211, a first grasping compensation module 212 and a first output control module 213. The gate of the main photosensitive transistor M01 and the gate of the auxiliary photosensitive transistor M02 are both electrically connected to the first node Q1.

[0038] The first terminal of the first charging module 211 is electrically connected to the second fixed voltage terminal V2, and the second terminal of the first charging module 211 is electrically connected to the first node Q2. The first charging module 211 is used to control the second fixed voltage terminal V2 to charge the first node Q1 in response to the first control signal S1.

[0039] The first grasping compensation module 212 is electrically connected to the first node Q1, and the first terminal of the first grasping compensation module 212 is electrically connected to the second node Q2 via the first terminal of the auxiliary phototransistor MO2. The second terminal of the first grasping compensation module 212 is electrically connected to the third node Q3 via the second terminal of the auxiliary phototransistor MO2. The first grasping compensation module 212 is used to control the first node Q1 after charging to discharge through the auxiliary phototransistor MO2 in response to the second control signal S2 until the potential of the first node Q1 is the sum of the potential at the third node Q3 and the threshold voltage of the auxiliary phototransistor MO2.

[0040] The first output control module 213 is electrically connected to the first node Q1, the second node Q2, the third node Q3, and the first fixed voltage terminal V1. The first output control module 213 is used to respond to the third control signal S3 and, after the potential of the first node Q1 is the sum of the potential at the third node Q3 and the threshold voltage of the auxiliary phototransistor M02, control the first fixed voltage terminal V1 to form a path with the auxiliary phototransistor M02, and at the same time control the first fixed voltage terminal V1 to form a path with the main phototransistor M01 to output the photoelectric signal to the signal detection unit 100.

[0041] Understandably, the first threshold grasping compensation unit provided in this embodiment of the invention firstly enables the first charging module 211 to operate by enabling the first control signal S1. The first charging module 211 controls the second fixed voltage terminal V2 to charge the first node Q1. After the first node Q1 is fully charged, the second control signal S2 enables the first grasping compensation module 212 to operate. The first grasping compensation module 212 controls the first node Q1 to discharge, and the discharge path is from the first node Q1 to the second node Q2. Then, the second node Q2 discharges through the auxiliary phototransistor MO2 to the third node Q3. Finally, the third node Q3 discharges through the first grasping compensation module 212 until the potential of the first node Q1 is the sum of the potential Vq3 at the third node Q3 and the threshold voltage Vth02 of the auxiliary phototransistor MO2 (Vq3 + Vth02). Finally, the third control signal S3 enables the first output control module 213 to operate. The first output control module 213 controls the first fixed voltage terminal V1 to form a path with the main photosensitive transistor M01 and outputs a photoelectric signal to the signal detection unit 100, wherein the photoelectric signal is the photoelectric current I = K*(Vgs-Vth01). 2 Vgs is the gate-source voltage of the main phototransistor M01, Vth01 is the threshold voltage of the main phototransistor M01, and V1' is the voltage of the first fixed voltage terminal V1. It can be seen that the Vgs voltage includes the Vth02 voltage. The photocurrent I output by the main phototransistor M01 can mitigate the impact of its threshold voltage offset through the formula (Vgs-Vth01). Furthermore, it can even eliminate the offset effect when the threshold voltage Vth02 of the auxiliary phototransistor M02 is the same as the threshold voltage Vth01 of the main phototransistor M01, thus improving the detection accuracy of the photoelectric detection circuit.

[0042] refer to Figure 3 The diagram shows a schematic of another photoelectric detection circuit provided in an embodiment of the present invention. The first charging module 211 provided in this embodiment includes a first transistor M1. The first end of the first transistor M1 is electrically connected to the second fixed voltage terminal V2, the second end of the first transistor M1 is electrically connected to the first node Q1, and the gate of the first transistor M1 is connected to the first control signal S1.

[0043] The first grasping compensation module includes a second transistor M2 and a third transistor M3; the first terminal of the second transistor M2 is electrically connected to the first node Q1, the second terminal of the second transistor M2 is electrically connected to the second node Q2, and the gate of the second transistor M2 is connected to the second control signal S2; the first terminal of the third transistor M3 is electrically connected to the third node Q3, the second terminal of the third transistor M3 is electrically connected to the third fixed voltage terminal V3, and the gate of the third transistor M3 is connected to the second control signal S2.

[0044] The first output control module includes a fourth transistor M4, a fifth transistor M5, and a first capacitor C1; the first terminal of the fourth transistor M4 is electrically connected to the first fixed voltage terminal V1, the second terminal of the fourth transistor M4 is electrically connected to the second node Q2, and the gate of the fourth transistor M4 is connected to the third control signal S3; the first terminal of the fifth transistor M5 is electrically connected to the third node Q3, the second terminal of the fifth transistor M5 is electrically connected to the third fixed voltage terminal V3, and the gate of the fifth transistor M5 is connected to the third control signal S3; the first terminal of the first capacitor C1 is electrically connected to the first node Q1, and the second terminal of the first capacitor C1 is connected to the third control signal S3.

[0045] In the photoelectric detection circuit provided in this embodiment of the invention, all transistors can be thin-film transistors, and any one of the transistors can be an N-type transistor or a P-type transistor; the invention does not impose specific limitations in this regard. For ease of description, all transistors in the photoelectric detection circuit provided in the following embodiments of the invention are described using N-type transistors as an example, wherein the enable levels of the first control signal to the third control signal are all high, the voltages of the first fixed voltage terminal and the second fixed voltage terminal are high, and the voltage of the third fixed voltage terminal V3 is low. (In conjunction with...) Figure 3 and Figure 4 As shown, Figure 4 A timing diagram provided for an embodiment of the present invention is provided, wherein the self-compensation detection of the photoelectric detection circuit includes three sequentially performed stages: charging stage T1, grasping compensation stage T2, and photoelectric detection stage T3, which correspond to the three enabling stages performed sequentially by the first control signal S1, the second control signal S2, and the third control signal S3, respectively.

[0046] During the charging phase T1, the first control signal S1 is enabled to a high level, and the first control signal S1 controls the first transistor M1 to turn on, and the second fixed voltage terminal V2 charges the first node Q1; at the same time, the second control signal S2 and the third control signal S3 are at a low level.

[0047] During the grasping compensation phase T2, the second control signal S2 is enabled to a high level, and the second control signal S2 controls the second transistor M2 and the third transistor M3 to conduct. The first node Q1 discharges through the path of the second transistor M2, the second node Q2, the auxiliary photosensitive transistor MO2, the third node Q3, and the third transistor M3 until the potential of the first node Q1 is the sum of the potential of the third node Q3 (i.e., the voltage of the third voltage terminal V3) and the threshold voltage of the auxiliary photosensitive transistor MO2; at the same time, the first control signal S1 and the third control signal S3 are at a low level.

[0048] During the photoelectric detection phase T3, the third control signal S3 is enabled to a high level, controlling the fourth transistor M4 and the fifth transistor M5 to conduct. The first capacitor C1 raises the voltage of the first node Q1, thereby controlling the auxiliary phototransistor M02 and the main phototransistor M01 to conduct. It is evident that since the voltage of the first node Q1 includes the threshold voltage information of the auxiliary phototransistor M02, and the gate voltage of the main phototransistor M01, whose gate is connected to the first node Q1, includes the threshold voltage information of the auxiliary phototransistor M02, the influence of the threshold voltage offset can be eliminated when the main phototransistor M01 generates photocurrent, thus improving the detection accuracy of the photoelectric detection circuit.

[0049] like Figure 5 The diagram shown is a structural schematic of another photoelectric detection circuit provided in an embodiment of the present invention. In this embodiment, the first fixed voltage terminal V1 and the second fixed voltage terminal V2 can be the same fixed voltage terminal to reduce the number of voltage ports and simplify the wiring of the photoelectric detection circuit.

[0050] Alternatively, in other embodiments of the present invention, the second fixed voltage terminal V2 and the first fixed voltage terminal V1 provided by the present invention are two independent voltage terminals, wherein the absolute value of the output voltage of the second fixed voltage terminal V2 is less than the absolute value of the output voltage of the first fixed voltage terminal V1, so as to avoid the situation where the photosensitive transistor is burned out due to the voltage of the second fixed voltage terminal V2 being too high during the charging stage.

[0051] refer to Figure 6 The diagram shows a structural schematic of another photoelectric detection circuit provided in an embodiment of the present invention. The first threshold capture compensation unit provided in this embodiment of the present invention further includes a first voltage divider module 214 electrically connected to the third node Q3. The first voltage divider module 214 is used to transmit a first preset voltage to the third node Q3 in response to the second control signal S2.

[0052] Continue as Figure 6As shown, the first voltage divider module 214 provided in this embodiment of the invention includes: a first resistor R1, a sixth transistor M6 and a seventh transistor M7; the first end of the first resistor R1 is electrically connected to the voltage divider terminal Vf, and the second end of the first resistor R1 is electrically connected to the first voltage divider node Qf1.

[0053] The first terminal of the sixth transistor M6 is electrically connected to the first voltage divider node Qf1, the second terminal of the sixth transistor M6 is electrically connected to the third fixed voltage terminal V3, and the gate of the sixth transistor M6 is electrically connected to the fourth control signal S4. The fourth control signal S4 controls the sixth transistor M6 to conduct when the second control signal S2 is enabled.

[0054] The first terminal of the seventh transistor M7 is electrically connected to the first voltage divider node Qf1, the second terminal of the seventh transistor M7 is electrically connected to the third node Q3, and the gate of the seventh transistor M7 is connected to the second control signal S2.

[0055] Understandably, the first voltage divider module 214 provided in this embodiment of the invention operates in response to the second control signal S2. That is, during the grasping compensation stage, the second control signal S2 transmits the first preset voltage obtained by the first voltage divider module 214 to the third node Q3. At this time, the first node Q1 discharges until the voltage of the first node Q1 is the sum of the first preset voltage and the threshold voltage of the auxiliary phototransistor MO2. This reduces the voltage difference change between the second node Q2 and the third node Q3 during the grasping compensation stage, avoids the probability of damage to the auxiliary phototransistor MO2, and improves the service life of the photoelectric detection circuit.

[0056] refer to Figure 7 The diagram shows a schematic of another photoelectric detection circuit provided in an embodiment of the present invention. In this embodiment, the voltage divider terminal Vf and the first fixed voltage terminal V1 are the same voltage terminal, and / or the port corresponding to the fourth control signal S4 is the same voltage terminal as the first fixed voltage terminal V1. The first voltage divider module 214 can divide the voltage of the first fixed voltage terminal V1 to obtain a first preset voltage, and the sixth transistor M6 can remain in a conducting state through the voltage of the first fixed voltage terminal V1. Based on the first voltage divider module 214 completing the voltage division and output of the first preset voltage, the number of voltage ports can be reduced, simplifying the photoelectric detection circuit.

[0057] Or, refer to Figure 8The diagram shows a schematic of another photoelectric detection circuit provided in an embodiment of the present invention. The voltage divider terminal Vf provided in this embodiment is the same port as the port corresponding to the second control signal S2, and / or the port corresponding to the fourth control signal S4 is the same port as the port corresponding to the second control signal S2. During the grasping compensation stage, the sixth transistor M6 can respond to the control of the second control signal S2 and be turned on, and the first voltage divider module 214 can divide the second control signal S2 to obtain a first preset voltage output. Based on the first voltage divider module 214 completing the voltage division and output of the first preset voltage, the number of voltage ports can be reduced, simplifying the photoelectric detection circuit. Simultaneously, the second control signal S2 only controls the sixth transistor M6 to be turned on during the grasping compensation stage, which can improve the characteristic drift phenomenon of the sixth transistor M6.

[0058] In one embodiment of the present invention, the photoelectric detection circuit provided by the present invention can determine the detected light intensity solely based on the photoelectric signal, as in any of the above embodiments. Alternatively, the photoelectric detection circuit provided in the embodiments of the present invention can also include a reference signal, and determine the light intensity based on the difference between the reference signal and the photoelectric signal, as detailed in the following reference. Figure 9 The diagram shown is a structural schematic of another photoelectric detection circuit provided in an embodiment of the present invention, wherein the photoelectric detection circuit further includes:

[0059] The main transistor M03 has its first terminal electrically connected to a preset voltage terminal Vy, and its second terminal is used to output a reference signal to the signal detection unit 100.

[0060] The auxiliary transistor M04 and the main transistor M03 are both located in a non-light-illuminated environment.

[0061] The second threshold grabbing compensation unit 220 is electrically connected to both the main transistor M03 and the auxiliary transistor M04. The second threshold grabbing compensation unit 220 is used to obtain the threshold voltage of the auxiliary transistor M04 and compensate the threshold voltage of the auxiliary transistor M04 to the gate of the main transistor M03.

[0062] Understandably, the technical solution provided in this embodiment of the invention includes an auxiliary phototransistor in the photodetector circuit, which operates under the same illumination conditions as the main phototransistor, ensuring that the threshold voltage shift of the auxiliary phototransistor is consistent with that of the main phototransistor. Therefore, the threshold voltage of the auxiliary phototransistor is captured and compensated to the gate of the main phototransistor by the first threshold capture and compensation unit. During the process of the main phototransistor generating a photoelectric signal based on the illumination intensity (i.e., during the generation of a photoelectric current), the influence of the threshold voltage shift of the main phototransistor on the generated photoelectric signal is reduced, thus improving the distortion of the output photoelectric signal caused by characteristic drift of the main phototransistor.

[0063] Simultaneously, the photoelectric detection circuit also includes an auxiliary transistor that operates under non-illuminated conditions, ensuring that the threshold voltage shift of the auxiliary transistor matches that of the main transistor. Therefore, the second threshold capture and compensation unit captures and compensates for the threshold voltage of the auxiliary transistor at the gate of the main transistor. During the generation of the reference signal by the main transistor (i.e., the generation of the reference current), the impact of the threshold voltage shift of the main transistor on the generated reference signal is reduced, mitigating the distortion of the output reference signal caused by characteristic drift of the main transistor. Furthermore, the signal detection unit compares the less distorted reference signal with the photoelectric signal to determine the illumination intensity information, thus improving the detection accuracy of the photoelectric detection circuit.

[0064] like Figure 9 As shown, the preset voltage terminal Vy and the first fixed voltage terminal V1 provided by the present invention can be the same voltage terminal, thereby reducing the number of ports in the photoelectric detection circuit and simplifying the wiring of the photoelectric detection circuit.

[0065] Or, continue as Figure 9 As shown, the preset voltage terminal Vy provided in this embodiment of the invention is the same port as the port corresponding to the third control signal S3. This reduces the number of ports in the photoelectric detection circuit and avoids burning out the main transistor M03 due to excessively high voltage in any stage other than the photoelectric detection stage, thereby improving the service life of the photoelectric detection circuit.

[0066] refer to Figure 10 The diagram shows a schematic of another photoelectric detection circuit provided in an embodiment of the present invention. The first threshold grasping compensation unit provided in this embodiment includes a first charging module 211, a first grasping compensation module 212, and a first output control module 213. The second threshold grasping compensation unit includes a second charging module 221, a second grasping compensation module 222, and a second output control module 223. The gate of the main transistor M03 and the gate of the auxiliary transistor M04 are both electrically connected to the fourth node Q4.

[0067] The first end of the second charging module 221 is electrically connected to the second fixed voltage terminal V2, and the second end of the second charging module 221 is electrically connected to the fourth node Q4. The second charging module 221 is used to control the second fixed voltage terminal V2 to charge the fourth node Q4 in response to the first control signal S1.

[0068] The second gripping compensation module 222 is electrically connected to the fourth node Q4, and the second gripping compensation module 222 is electrically connected to the first terminal of the auxiliary transistor M04 at the fifth node Q5. The second gripping compensation module 222 is electrically connected to the second terminal of the auxiliary transistor M04 at the sixth node Q6. The second gripping compensation module 222 is used to control the charged fourth node Q4 to discharge through the auxiliary transistor M04 in response to the second control signal S2 until the potential of the fourth node Q4 is the sum of the potential at the sixth node Q6 and the threshold voltage of the auxiliary transistor M04.

[0069] The second output control module 223 is electrically connected to the fourth node Q4, the fifth node Q5, the sixth node Q6, and the first fixed voltage terminal V1. The second output control module 223 is used to respond to the third control signal S3 and, after the potential of the fourth node Q4 is the sum of the potential at the sixth node Q6 and the threshold voltage of the auxiliary transistor MO4, control the first fixed voltage terminal V1 to form a path with the auxiliary transistor MO4, and at the same time control the preset voltage terminal Vy to form a path with the main transistor MO3 to output the photoelectric signal.

[0070] As can be understood, in the technical solution provided by the embodiments of the present invention, the first control signal S1 is first enabled to control the first charging module 211 and the second charging module 221 to work. The first charging module 211 controls the second fixed voltage terminal V2 to charge the first node Q1, while the second charging module 221 controls the second fixed voltage terminal V2 to charge the fourth node Q4. After the first node Q1 and the fourth node Q4 have finished charging, the second control signal S2 enables the first grasping compensation module 212 and the second grasping compensation module 222 to operate. The first grasping compensation module 212 controls the first node Q1 to discharge, and the discharge path is from the first node Q1 to the second node Q2. Then the second node Q2 discharges through the auxiliary phototransistor MO2 to the third node Q3. Finally, the third node Q3 discharges through the first grasping compensation module 212 until the potential of the first node Q1 is the sum of the potential at the third node Q3 and the threshold voltage of the auxiliary phototransistor MO2. Similarly, the fourth node Q4 discharges until its potential is the sum of the potential of the sixth node Q6 and the threshold voltage of the auxiliary transistor MO4. Finally, the third control signal S3 enables the first output control module 213 and the second output control module 223 to operate. The first output control module 213 controls the first fixed voltage terminal V1 to form a path with the main photosensitive transistor M01 and outputs a photoelectric signal to the signal detection unit 100. At the same time, the second output control module 223 controls the preset voltage terminal Vy to form a path with the main transistor M03 and outputs a reference signal to the signal detection unit 100. The signal detection unit 100 compares the reference signal and the photoelectric signal to determine the light intensity and completes the photoelectric detection process.

[0071] refer to Figure 11 The diagram shows a schematic of another photoelectric detection circuit provided in an embodiment of the present invention. The second charging module provided in this embodiment of the present invention includes an eighth transistor M8. The first terminal of the eighth transistor M8 is electrically connected to the second fixed voltage terminal V2, the second terminal of the eighth transistor M8 is electrically connected to the fourth node Q4, and the gate of the eighth transistor M8 is connected to the first control signal S1.

[0072] The second grasping compensation module includes a ninth transistor M9 and a tenth transistor M10; the first terminal of the ninth transistor M9 is electrically connected to the fourth node Q4, the second terminal of the ninth transistor M9 is electrically connected to the fifth node Q5, and the gate of the ninth transistor M9 is connected to the second control signal S2; the first terminal of the tenth transistor M10 is electrically connected to the sixth node Q6, the second terminal of the tenth transistor M10 is electrically connected to the third fixed voltage terminal V3, and the gate of the tenth transistor M10 is connected to the second control signal S2.

[0073] The second output control module includes an eleventh transistor M11, a twelfth transistor M12, and a second capacitor. The first terminal of the eleventh transistor M11 is electrically connected to the first fixed voltage terminal V1, and the second terminal of the eleventh transistor M11 is electrically connected to the fifth node Q5. The gate of the eleventh transistor M11 is connected to the third control signal S3. The first terminal of the twelfth transistor M12 is electrically connected to the sixth node Q6, and the second terminal of the twelfth transistor M12 is electrically connected to the third fixed voltage terminal V3. The gate of the twelfth transistor M12 is connected to the third control signal S3. The first terminal of the second capacitor is electrically connected to the fourth node Q4, and the second terminal of the second capacitor is connected to the third control signal S3.

[0074] In one embodiment of the present invention, the first fixed voltage terminal V1 and the second fixed voltage terminal V2 provided by the present invention can be the same fixed voltage terminal, and the output is the voltage of the first fixed voltage terminal V1; or, the first fixed voltage terminal V1 and the second fixed voltage terminal V2 are independent voltage terminals, and the absolute value of the output voltage of the second fixed voltage terminal V2 is less than the absolute value of the output voltage of the first fixed voltage terminal V1. The specific selection needs to be made according to the actual application.

[0075] It should be noted that the working process of the second threshold grasping compensation unit provided in this embodiment of the invention is consistent with the working process of the first threshold grasping compensation unit, therefore, in combination with Figure 4 The timing diagram shown can be used to analyze the working process of the photoelectric detection circuit, and the present invention will not elaborate further on this.

[0076] refer to Figure 12 The diagram shows a schematic of another photoelectric detection circuit provided in an embodiment of the present invention. The first threshold capture compensation unit further includes the first voltage divider module 214, and the second threshold capture compensation unit further includes the second voltage divider module 224. The second voltage divider module 224 is used to transmit the second preset voltage to the sixth node Q6 in response to the second control signal S2.

[0077] Continue as Figure 12 As shown, the first voltage divider module 214 includes: a first resistor R1, a sixth transistor M6, and a seventh transistor M7; wherein, the second voltage divider module 224 includes: a second resistor R2, a voltage-dividing photosensitive transistor Mf, and a thirteenth transistor M13. The first end of the second resistor R2 is electrically connected to the voltage divider terminal Vf, and the second end of the second resistor R2 is electrically connected to the second voltage divider node Qf2.

[0078] The first terminal of the voltage divider photosensitive transistor Mf is electrically connected to the second voltage divider node Qf2, the second terminal of the voltage divider photosensitive transistor Mf is electrically connected to the third fixed voltage terminal V3, and the gate of the voltage divider photosensitive transistor Mf is electrically connected to the fourth control signal S4. The voltage divider photosensitive transistor Mf, the auxiliary photosensitive transistor M02, and the main photosensitive transistor M01 are all located under the same lighting environment conditions.

[0079] The first terminal of the thirteenth transistor M13 is electrically connected to the second voltage divider node Qf2, the second terminal of the thirteenth transistor M13 is electrically connected to the sixth node Q6, and the gate of the thirteenth transistor M13 is connected to the second control signal S2.

[0080] It is understood that the current generated by the voltage divider phototransistor Mf provided in the embodiments of the present invention changes according to the light intensity. The greater the light intensity, the greater the current generated by the voltage divider phototransistor Mf, that is, the lower the second preset voltage. This ensures that the difference between the first preset voltage and the second preset voltage is large, increasing the difference between the reference signal and the photoelectric signal, thereby improving the degree of difference between the reference signal and the photoelectric signal, that is, improving the sensitivity of the photoelectric detection circuit.

[0081] In one embodiment of the present invention, the voltage divider terminal Vf provided in this embodiment is the same voltage terminal as the first fixed voltage terminal V1, and the output is the voltage of the first fixed voltage terminal V1. Alternatively, the port corresponding to the fourth control signal S4 is the same voltage terminal as the first fixed voltage terminal V1, and the output is the voltage of the first fixed voltage terminal V1. The sixth transistor M6 and the voltage divider photosensitive transistor Mf can remain in a conducting state through the voltage of the first fixed voltage terminal V1. Alternatively, the voltage divider terminal Vf provided in this embodiment is the same port as the port corresponding to the second control signal S2, and the output is the corresponding signal of the second control signal S2. Alternatively, the port corresponding to the fourth control signal S4 is the same port as the port corresponding to the second control signal S2, and the output is the corresponding signal of the second control signal S2. In this case, during the grasping compensation phase, the sixth transistor M6 and the voltage divider photosensitive transistor Mf can respond to the control of the second control signal S2 and be turned on.

[0082] Accordingly, embodiments of the present invention also provide a display device, the display device including the photoelectric detection circuit provided in any of the above embodiments.

[0083] refer to Figure 13 The diagram shown is a structural schematic of a display device provided in an embodiment of the present invention. The display device provided in this embodiment of the present invention can be a mobile terminal 1000, and the mobile terminal includes the photoelectric detection circuit provided in any of the above embodiments.

[0084] It should be noted that the display device provided in the embodiments of the present invention can also be a laptop, tablet computer, computer, wearable device, etc., and the present invention does not impose specific limitations on it.

[0085] This invention provides a photoelectric detection circuit and display device, comprising: a main photosensitive transistor, wherein a first terminal of the main photosensitive transistor is electrically connected to a first fixed voltage terminal, and a second terminal of the main photosensitive transistor is used to output a photoelectric signal; an auxiliary photosensitive transistor, wherein the auxiliary photosensitive transistor and the main photosensitive transistor are both located under the same illumination environment; and a first threshold capture compensation unit, wherein the first threshold capture compensation unit is electrically connected to both the main photosensitive transistor and the auxiliary photosensitive transistor, and the first threshold capture compensation unit is used to acquire the threshold voltage of the auxiliary photosensitive transistor and compensate the threshold voltage of the auxiliary photosensitive transistor to the gate of the main photosensitive transistor.

[0086] As can be seen from the above, the technical solution provided by the embodiments of the present invention includes an auxiliary phototransistor in the photoelectric detection circuit that is under the same lighting environment as the main phototransistor. The threshold voltage of the auxiliary phototransistor is captured and compensated to the gate of the main phototransistor by the first threshold capture and compensation unit. In this way, the influence of the threshold voltage deviation of the main phototransistor on the generated photoelectric signal can be reduced, the distortion of the output photoelectric signal caused by the characteristic drift of the main phototransistor can be improved, and the detection accuracy of the photoelectric detection circuit can be improved.

[0087] In the description of this invention, it should be understood that terms such as "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0088] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0089] In this invention, unless otherwise explicitly specified and limited, terms such as "installation," "connection," "linking," and "fixing" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection, an electrical connection, or a connection that allows communication between components; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0090] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "over," and "on top" of the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0091] In this invention, the terms "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0092] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention.

Claims

1. A photoelectric detection circuit, characterized in that, include: A main photosensitive transistor, wherein the first terminal of the main photosensitive transistor is electrically connected to a first fixed voltage terminal, and the second terminal of the main photosensitive transistor is used to output photoelectric signals; An auxiliary photosensitive transistor, wherein the auxiliary photosensitive transistor and the main photosensitive transistor are both located under the same lighting environment conditions; And, a first threshold grasping compensation unit, which is electrically connected to both the main photosensitive transistor and the auxiliary photosensitive transistor, and is electrically connected to the gate, first terminal and second terminal of the auxiliary photosensitive transistor, and is electrically connected to the gate of the main photosensitive transistor. The first threshold grasping compensation unit is used to obtain the threshold voltage of the auxiliary photosensitive transistor and compensate the threshold voltage of the auxiliary photosensitive transistor to the gate of the main photosensitive transistor. The first threshold grasping compensation unit includes: a first charging module, a first grasping compensation module, and a first output control module, wherein the gate of the main photosensitive transistor and the gate of the auxiliary photosensitive transistor are both electrically connected to the first node; The first end of the first charging module is electrically connected to the second fixed voltage end, and the second end of the first charging module is electrically connected to the first node. The first charging module is used to control the second fixed voltage end to charge the first node in response to the first control signal. The first grasping compensation module is electrically connected to the first node, and the first grasping compensation module is electrically connected to the first terminal of the auxiliary phototransistor at the second node, and the first grasping compensation module is electrically connected to the second terminal of the auxiliary phototransistor at the third node. The first grasping compensation module is used to control the first node after charging to discharge through the auxiliary phototransistor in response to the second control signal until the potential of the first node is the sum of the potential at the third node and the threshold voltage of the auxiliary phototransistor. The first output control module is electrically connected to the first node, the second node, the third node, and the first fixed voltage terminal. The first output control module is used to respond to the third control signal and, after the potential of the first node is the sum of the potential at the third node and the threshold voltage of the auxiliary phototransistor, control the first fixed voltage terminal to form a path with the auxiliary phototransistor, and at the same time control the first fixed voltage terminal to form a path with the main phototransistor to output the photoelectric signal.

2. The photoelectric detection circuit according to claim 1, characterized in that, The first charging module includes a first transistor, a first terminal of the first transistor is electrically connected to the second fixed voltage terminal, a second terminal of the first transistor is electrically connected to the first node, and the gate of the first transistor is connected to the first control signal. The first grasping compensation module includes a second transistor and a third transistor; the first terminal of the second transistor is electrically connected to the first node, the second terminal of the second transistor is electrically connected to the second node, and the gate of the second transistor is connected to the second control signal; the first terminal of the third transistor is electrically connected to the third node, the second terminal of the third transistor is electrically connected to a third fixed voltage terminal, and the gate of the third transistor is connected to the second control signal. The first output control module includes a fourth transistor, a fifth transistor, and a first capacitor; the first terminal of the fourth transistor is electrically connected to the first fixed voltage terminal, the second terminal of the fourth transistor is electrically connected to the second node, and the gate of the fourth transistor is connected to the third control signal; the first terminal of the fifth transistor is electrically connected to the third node, the second terminal of the fifth transistor is electrically connected to the third fixed voltage terminal, and the gate of the fifth transistor is connected to the third control signal; the first terminal of the first capacitor is electrically connected to the first node, and the second terminal of the first capacitor is connected to the third control signal.

3. The photoelectric detection circuit according to claim 1, characterized in that, The first fixed voltage terminal and the second fixed voltage terminal are the same fixed voltage terminal; Alternatively, the absolute value of the output voltage at the second fixed voltage terminal is less than the absolute value of the output voltage at the first fixed voltage terminal.

4. The photoelectric detection circuit according to claim 1, characterized in that, The first threshold capture compensation unit further includes a first voltage divider module electrically connected to the third node, the first voltage divider module being used to transmit a first preset voltage to the third node in response to the second control signal.

5. The photoelectric detection circuit according to claim 4, characterized in that, The first voltage divider module includes: a first resistor, a sixth transistor, and a seventh transistor; The first end of the first resistor is electrically connected to the voltage divider terminal, and the second end of the first resistor is electrically connected to the first voltage divider node; The first terminal of the sixth transistor is electrically connected to the first voltage divider node, the second terminal of the sixth transistor is electrically connected to the third fixed voltage terminal, and the gate of the sixth transistor is electrically connected to the fourth control signal. The first terminal of the seventh transistor is electrically connected to the first voltage divider node, the second terminal of the seventh transistor is electrically connected to the third node, and the gate of the seventh transistor is connected to the second control signal.

6. The photoelectric detection circuit according to claim 5, characterized in that, The voltage divider terminal is the same voltage terminal as the first fixed voltage terminal, and / or the port corresponding to the fourth control signal is the same voltage terminal as the first fixed voltage terminal; Alternatively, the voltage divider terminal and the port corresponding to the second control signal are the same port, and / or the port corresponding to the fourth control signal and the port corresponding to the second control signal are the same port.

7. The photoelectric detection circuit according to any one of claims 1-6, characterized in that, The photoelectric detection circuit also includes: The main transistor has a first terminal electrically connected to a preset voltage terminal and a second terminal used to output a reference signal. An auxiliary transistor, wherein both the auxiliary transistor and the main transistor are located in a non-light-illuminated environment; The second threshold grabbing compensation unit is electrically connected to both the main transistor and the auxiliary transistor. The second threshold grabbing compensation unit is used to obtain the threshold voltage of the auxiliary transistor and compensate the threshold voltage of the auxiliary transistor to the gate of the main transistor.

8. The photoelectric detection circuit according to claim 7, characterized in that, The preset voltage terminal and the first fixed voltage terminal are the same voltage terminal; Alternatively, the preset voltage terminal and the port corresponding to the third control signal are the same port.

9. The photoelectric detection circuit according to claim 7, characterized in that, The first threshold grasping compensation unit includes the first charging module, the first grasping compensation module, and the first output control module, wherein the second threshold grasping compensation unit includes the second charging module, the second grasping compensation module, and the second output control module, and the gate of the main transistor and the gate of the auxiliary transistor are both electrically connected to the fourth node; The first end of the second charging module is electrically connected to the second fixed voltage terminal, and the second end of the second charging module is electrically connected to the fourth node. The second charging module is used to control the second fixed voltage terminal to charge the fourth node in response to the first control signal. The second grasping compensation module is electrically connected to the fourth node, and the second grasping compensation module is electrically connected to the first end of the auxiliary transistor at the fifth node, and the second grasping compensation module is electrically connected to the second end of the auxiliary transistor at the sixth node. The second grasping compensation module is used to control the charged fourth node to discharge through the auxiliary transistor in response to the second control signal until the potential of the fourth node is the sum of the potential at the sixth node and the threshold voltage of the auxiliary transistor. The second output control module is electrically connected to the fourth node, the fifth node, the sixth node and the first fixed voltage terminal. The second output control module is used to respond to the third control signal and, after the potential of the fourth node is the sum of the potential at the sixth node and the threshold voltage of the auxiliary transistor, control the first fixed voltage terminal to form a path with the auxiliary transistor, and at the same time control the preset voltage terminal to form a path with the main transistor to output the photoelectric signal.

10. The photoelectric detection circuit according to claim 9, characterized in that, The second charging module includes an eighth transistor, the first terminal of which is electrically connected to the second fixed voltage terminal, the second terminal of which is electrically connected to the fourth node, and the gate of which is connected to the first control signal. The second grasping compensation module includes a ninth transistor and a tenth transistor; the first terminal of the ninth transistor is electrically connected to the fourth node, the second terminal of the ninth transistor is electrically connected to the fifth node, and the gate of the ninth transistor is connected to the second control signal; the first terminal of the tenth transistor is electrically connected to the sixth node, the second terminal of the tenth transistor is electrically connected to the third fixed voltage terminal, and the gate of the tenth transistor is connected to the second control signal. The second output control module includes an eleventh transistor, a twelfth transistor, and a second capacitor; the first terminal of the eleventh transistor is electrically connected to the first fixed voltage terminal, the second terminal of the eleventh transistor is electrically connected to the fifth node, and the gate of the eleventh transistor is connected to the third control signal; the first terminal of the twelfth transistor is electrically connected to the sixth node, the second terminal of the twelfth transistor is electrically connected to the third fixed voltage terminal, and the gate of the twelfth transistor is connected to the third control signal; the first terminal of the second capacitor is electrically connected to the fourth node, and the second terminal of the second capacitor is connected to the third control signal.

11. The photoelectric detection circuit according to claim 9, characterized in that, The first threshold capture compensation unit further includes a first voltage divider module electrically connected to the third node. The first voltage divider module is used to transmit a first preset voltage to the third node in response to the second control signal. The second threshold capture compensation unit further includes a second voltage divider module, which is used to transmit a second preset voltage to the sixth node in response to the second control signal.

12. The photoelectric detection circuit according to claim 11, characterized in that, The first voltage divider module includes: a first resistor, a sixth transistor, and a seventh transistor; the first end of the first resistor is electrically connected to the voltage divider terminal, and the second end of the first resistor is electrically connected to the first voltage divider node; the first end of the sixth transistor is electrically connected to the first voltage divider node, the second end of the sixth transistor is electrically connected to the third fixed voltage terminal, and the gate of the sixth transistor is electrically connected to the fourth control signal; the first end of the seventh transistor is electrically connected to the first voltage divider node, the second end of the seventh transistor is electrically connected to the third node, and the gate of the seventh transistor is connected to the second control signal; wherein, the second voltage divider module includes: a second resistor, a voltage divider photosensitive transistor, and a thirteenth transistor; The first end of the second resistor is electrically connected to the voltage divider terminal, and the second end of the second resistor is electrically connected to the second voltage divider node; The first terminal of the voltage divider photosensitive transistor is electrically connected to the second voltage divider node, the second terminal of the voltage divider photosensitive transistor is electrically connected to the third fixed voltage terminal, and the gate of the voltage divider photosensitive transistor is electrically connected to the fourth control signal. The voltage divider photosensitive transistor, the auxiliary photosensitive transistor, and the main photosensitive transistor are all located under the same lighting environment conditions. The first terminal of the thirteenth transistor is electrically connected to the second voltage divider node, the second terminal of the thirteenth transistor is electrically connected to the sixth node, and the gate of the thirteenth transistor is connected to the second control signal.

13. A display device, characterized in that, The display device includes the photoelectric detection circuit according to any one of claims 1-12.

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