A photodetector and display device

Abstract

This invention discloses a photodetector and a display device. The photodetector includes a photosensitive circuit and a compensation circuit. The photosensitive circuit includes a first transistor, which is a phototransistor. The compensation circuit is electrically connected to the gate of the first transistor and is used to perform threshold compensation on the gate of the first transistor. In this invention, the photosensitive circuit includes a first transistor, which is a phototransistor and is prone to characteristic drift under prolonged illumination. The compensation circuit is electrically connected to the gate of the first transistor and is used to perform threshold compensation on the gate of the first transistor, solving the characteristic drift problem of the first transistor caused by illumination, improving the stability of the first transistor, and thus improving the detection accuracy of the photodetector.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of light detection technology, and in particular to a light detector and a display device. BACKGROUND

[0002] With the rapid development of display devices, people are increasingly dependent on display devices. When using display devices for a long time, the brightness of ambient light may change, and if the brightness of the display screen cannot be adjusted in time, it will cause harm to the user's vision or make the display picture unclear.

[0003] At present, a light detector is integrated in a display device, and the light detector can detect ambient light. However, the characteristics of the transistor in the existing light detector will deviate, affecting the detection accuracy. SUMMARY

[0004] The present application provides a light detector and a display device to solve the problem of characteristic deviation of the transistor in the existing light detector.

[0005] According to an aspect of the present application, a light detector is provided, comprising: a light sensing circuit and a compensation circuit;

[0006] The light sensing circuit comprises a first transistor, and the first transistor is a photosensitive transistor.

[0007] The compensation circuit is electrically connected to the gate of the first transistor and is used for threshold compensation of the gate of the first transistor.

[0008] According to another aspect of the present application, a display device is provided, comprising: a light detector as described above, which is used for detecting ambient light.

[0009] In the present application, the light sensing circuit comprises a first transistor, and the first transistor is a photosensitive transistor, which is prone to characteristic drift under long-time light exposure. The compensation circuit is electrically connected to the gate of the first transistor and is used for threshold compensation of the gate of the first transistor, solving the problem of characteristic drift of the first transistor caused by light exposure and improving the stability of the first transistor, thereby improving the detection accuracy of the light detector.

[0010] It should be understood that the content described in this part is not intended to identify key or important features of the embodiments of the present application, nor is it used to limit the scope of the present application. Other features of the present application will become apparent from the following description. BRIEF DESCRIPTION OF DRAWINGS

[0011] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0012] Figure 1 This is a schematic diagram of a photodetector provided in an embodiment of the present invention;

[0013] Figure 2 This is a schematic diagram of another photodetector provided in an embodiment of the present invention;

[0014] Figure 3 This is a schematic diagram of another type of photodetector provided in an embodiment of the present invention;

[0015] Figure 4 This is a schematic diagram of another type of photodetector provided in an embodiment of the present invention;

[0016] Figure 5 This is a schematic diagram of another type of photodetector provided in an embodiment of the present invention;

[0017] Figure 6 This is a schematic diagram of another type of photodetector provided in an embodiment of the present invention;

[0018] Figure 7 This is a schematic diagram of another type of photodetector provided in an embodiment of the present invention;

[0019] Figure 8 This is a comparative diagram of photodetectors with and without compensation circuits.

[0020] Figure 9 This is a schematic diagram of a display device provided in an embodiment of the present invention. Detailed Implementation

[0021] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. 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 should fall within the scope of protection of the present invention.

[0022] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of the invention described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover a non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0023] Figure 1 This is a schematic diagram of a photodetector provided in an embodiment of the present invention. The photodetector provided in this embodiment is applicable to detecting ambient light. This photodetector can be integrated into any display device to sense the intensity of light in the surrounding environment, for example, integrated into a smartphone to detect ambient light and adjust the screen brightness accordingly. Figure 1 As shown, the photodetector includes a photosensitive circuit 11 and a compensation circuit 12; the photosensitive circuit 11 includes a first transistor M1, which is a photosensitive transistor; the compensation circuit 12 is electrically connected to the gate of the first transistor M1 and is used to perform threshold compensation on the gate of the first transistor M1.

[0024] In this embodiment, the photodetector includes a photosensitive circuit 11, which is electrically connected to a compensation circuit 12. The photosensitive circuit 11 senses light signals under illumination and generates and outputs an electrical signal under the drive of the compensation circuit 12. The photosensitive circuit 11 includes a first transistor M1, which is a phototransistor. A phototransistor, also known as a photoelectric transistor, is a semiconductor phototransistor device made using the photoelectric effect principle of semiconductor materials. The most distinctive feature of a phototransistor is that its casing has a photosensitive window. This window is unobstructed and can be illuminated by light. The phototransistor senses light signals through the photosensitive window and generates and outputs an electrical signal that characterizes the light signal. This electrical signal characterizes the effect of illumination on the phototransistor; changes in the illumination received by the phototransistor cause corresponding changes in the output electrical signal.

[0025] The photodetector also includes a compensation circuit 12, which is electrically connected to the photosensitive circuit 11. The compensation circuit 12 is electrically connected to the gate of the first transistor M1 in the photosensitive circuit 11, and is used to perform threshold compensation on the gate of the first transistor M1. The gate of the first transistor M1 is connected to the compensation circuit 12, and the first transistor M1 can sense light signals. Based on this, the compensation circuit 12 controls the first transistor M1 to be turned on or off. When the first transistor M1 is turned on, it generates and outputs an electrical signal characterizing the effect of light illumination. This electrical signal is the current flowing through the first transistor M1. It can be understood that changes in the light illumination received by the first transistor M1 will cause a corresponding change in the current flowing through it.

[0026] Phototransistors are used for light sensing to characterize the effects of illumination. However, after prolonged light exposure, phototransistors are susceptible to characteristic drift caused by illumination. For example, the threshold voltage of the phototransistor may drift, affecting its stability and causing a shift in the output signal, thus impacting the detection accuracy of the photodetector. Therefore, the gate of the first transistor M1 suffers from threshold characteristic drift due to prolonged illumination. In this embodiment, a compensation circuit 12 is added to the photodetector to compensate for the threshold voltage drift of the first transistor M1, reducing the characteristic drift caused by illumination, decreasing the shift in the output signal of the first transistor M1, improving the stability of the first transistor M1, and enhancing the detection accuracy of the photodetector.

[0027] It should be noted that the first transistor M1 serves as the illumination transistor, and the second transistor M2 serves as the compensation transistor, and they are arranged adjacent to each other. Similar illumination conditions mean that the first transistor M1 and the second transistor M2 are simultaneously illuminated, or simultaneously not illuminated. No light-shielding layer is placed above the first transistor M1 and the second transistor M2. The function of the compensation circuit 12 is to detect the characteristic (threshold voltage) drift of the illumination transistor and compensate for it. Then, the illumination transistor uses the compensated gate voltage for output.

[0028] In this invention, the photosensitive circuit includes a first transistor, which is a photosensitive transistor and is prone to characteristic drift under prolonged illumination. The compensation circuit is electrically connected to the gate of the first transistor and is used to perform threshold compensation on the gate of the first transistor to solve the characteristic drift problem of the first transistor caused by illumination, improve the stability of the first transistor, and thus improve the detection accuracy of the photodetector.

[0029] The optional photosensitive circuit also includes a first resistor, with a first end connected to a third signal terminal, and a first transistor connected between a second end of the first resistor and a second power supply terminal. The third signal terminal is connected to a second timing line; alternatively, the third signal terminal is connected to the first power supply terminal.

[0030] Figure 2 This is a schematic diagram of another photodetector provided in an embodiment of the present invention. Figure 2 As shown, the photosensitive circuit 11 also includes a first resistor R1. Optionally, the third signal terminal is connected to the first power supply terminal V1, in which case the first terminal of the first resistor R1 is connected to the first power supply terminal V1, and the first transistor M1 is connected between the second terminal of the first resistor R1 and the second power supply terminal V2. The second terminal of the first resistor R1 outputs a voltage divider signal Vo. Optionally, the first transistor M1 is an NMOS. Optionally, the first power supply terminal V1 provides a constant high-level signal, and the second power supply terminal V2 provides a constant low-level signal. In other embodiments, the first transistor may also be a PMOS, but specific examples are not provided.

[0031] Before compensation, the first transistor M1 experiences characteristic drift due to illumination, causing a shift in the voltage divider signal output from the second terminal of the first resistor R1, resulting in poor detection accuracy of the photodetector. After the compensation circuit 12 compensates for the threshold voltage drift of the first transistor M1, it reduces the characteristic drift caused by illumination. This compensates for the shift in the voltage divider signal Vo output from the second terminal of the first resistor R1, improving the stability of the first transistor M1 and enhancing the detection accuracy of the photodetector.

[0032] Optionally, the second terminal of the first resistor R1 can also be connected to the subsequent circuit. Then, the voltage divider signal Vo output by the first resistor R1 is transmitted to the subsequent circuit. The subsequent circuit analyzes and processes the Vo signal, which can detect ambient light and achieve the effect of sensing the intensity of light in the surrounding environment.

[0033] The optional compensation circuit includes a charging unit, a discharging unit, and a compensation unit; the compensation unit includes a second transistor, which is the same phototransistor as the first transistor, the gate of the second transistor is connected to the gate of the first transistor, and the second transistor is connected between the first node N1 and the first signal terminal N2; the charging unit is connected between the first power supply terminal and the gate of the second transistor; the discharging unit is connected between the gate of the second transistor and the first node.

[0034] Figure 3 This is a schematic diagram of another type of photodetector provided in an embodiment of the present invention. Figure 3 As shown, the compensation circuit 12 includes a charging unit 13, a discharging unit 14, and a compensation unit 15. The compensation unit 15 includes a second transistor M2, which is the same phototransistor as the first transistor M1. The gate of the second transistor M2 is connected to the gate of the first transistor M1, and the second transistor M2 is connected between the first node N1 and the first signal terminal N2. The charging unit 13 is connected between the first power supply terminal V1 and the gate of the second transistor M2. The discharging unit 14 is connected between the gate of the second transistor M2 and the first node N1.

[0035] In this embodiment, the charging unit 13 is connected between the first power supply terminal V1 and the gate of the second transistor M2. The charging unit 13 is selectively turned on, and when turned on, it writes the electrical signal of the first power supply terminal V1 into the gate of the second transistor M2. The discharging unit 14 is connected between the gate of the second transistor M2 and the first node N1. The discharging unit 14 is selectively turned on, and when turned on, it discharges the gate of the second transistor M2.

[0036] The compensation unit 15 includes a second transistor M2, which is the same phototransistor as the first transistor M1. The gate of the second transistor M2 is connected to the gate of the first transistor M1, and the second transistor M2 is connected between the first node N1 and the first signal terminal N2. The second transistor M2 is selectively turned on to perform threshold compensation on the gate of the first transistor M1. Specifically, since the second transistor M2 is the same phototransistor as the first transistor M1, the illumination conditions of the second transistor M2 and the first transistor M1 are similar, which ensures that the characteristic drift of the second transistor M2 and the first transistor M1 is similar. Therefore, the characteristic drift of the first transistor M1 can be compensated by the second transistor M2. Optionally, the first transistor M1 and the second transistor M2 can be the same NMOS, but are not limited to NMOS. In other embodiments, PMOS can also be selected.

[0037] The aspect ratio of the second transistor M2 can be the same as that of the first transistor M1. The second transistor M2 and the first transistor M1 are turned on or off synchronously. Under the same illumination, the illumination conditions of the second transistor M2 and the first transistor M1 are the same, which can ensure that the characteristic drift of the second transistor M2 and the first transistor M1 is almost the same. The characteristic drift of the first transistor M1 can be compensated by the second transistor M2.

[0038] The optional charging unit includes a third transistor, the gate of which is connected to a first timing line; the discharging unit includes a fourth transistor, the gate of which is connected to a second timing line. Both the optional third and fourth transistors are NMOS transistors.

[0039] Figure 4 This is a schematic diagram of another type of photodetector provided in an embodiment of the present invention. Figure 4As shown, the charging unit 13 includes a third transistor M3, the gate of which is connected to the first timing line ST1. The third transistor M3 is connected between the first power supply terminal V1 and the gate of the second transistor M2. The third transistor M3 is selectively turned on under the control of the first timing line ST1. The discharging unit 14 includes a fourth transistor M4, the gate of which is connected to the second timing line ST2. The fourth transistor M4 is connected between the gate of the second transistor M2 and the first node N1. The fourth transistor M4 is selectively turned on under the control of the second timing line ST2.

[0040] Optionally, both the third transistor M3 and the fourth transistor M4 can be NMOS. In other embodiments, the third transistor can also be PMOS, and / or the fourth transistor can be PMOS.

[0041] by Figure 4 Taking the NMOS transistor as an example, a high-level signal output from the first timing line ST1 turns on the third transistor M3, and a low-level signal output from the first timing line ST1 turns off the third transistor M3. When the third transistor M3 is on, the electrical signal at the first power supply terminal V1 is written into the gate of the second transistor M2. A high-level signal output from the second timing line ST2 turns on the fourth transistor M4, and a low-level signal output from the second timing line ST2 turns off the fourth transistor M4. When the fourth transistor M4 is on, the gate of the second transistor M2 is discharged to the first node N1.

[0042] The optional compensation circuit further includes a voltage divider unit; the voltage divider unit includes a second resistor and a third resistor, the first ends of the second resistor and the third resistor are connected to a first signal terminal, the second end of the second resistor is connected to a second signal terminal, and the second end of the third resistor is connected to a second power supply terminal. Optionally, the second signal terminal is connected to a second timing line; alternatively, the second signal terminal is connected to the first power supply terminal. The optional photodetector includes a charging stage and a compensation stage; during the charging stage, the third transistor is turned on, allowing the signal from the first power supply terminal to be written into the gate of the first transistor; during the compensation stage, the second transistor and a fourth transistor are turned on, allowing the gate of the first transistor to discharge to the first signal terminal through the fourth transistor.

[0043] Figure 5 This is a schematic diagram of another type of photodetector provided in an embodiment of the present invention. Figure 5As shown, the compensation circuit 12 also includes a voltage divider unit 16; the voltage divider unit 16 includes a second resistor R2 and a third resistor R3. The first ends of the second resistor R2 and the third resistor R3 are connected to the first signal terminal N2, and the second end of the second resistor R2 is connected to the second signal terminal, which is connected to the second timing line ST2; the second end of the third resistor R3 is connected to the second power supply terminal V2. All transistors can be NMOS. Optionally, the first power supply terminal V1 can provide a high-level signal VGH, and the second power supply terminal V2 can provide a low-level signal VGL. It should be noted that if the second timing line ST2 provides a stable signal during the compensation phase, the voltage at the first signal terminal N2 will be fixed during this compensation phase.

[0044] Figure 6 This is a schematic diagram of another photodetector provided in an embodiment of the present invention. Figure 5 The difference is that, Figure 6 The second end of the second resistor R2 is connected to the second signal terminal, and the second signal terminal is connected to the first power supply terminal V1. It should be noted that since the first power supply terminal V1 provides a constant signal, the voltage at the first signal terminal N2 remains constant.

[0045] In this embodiment, the working process of the photodetector includes a charging phase and a compensation phase executed sequentially. Figure 5 and Figure 6 The working principle and process are the same. Here, we will only use... Figure 5 The photodetector shown is used as an example for explanation.

[0046] The working process of a photodetector is as follows:

[0047] During the charging phase, a high-level signal is provided by the first timing line ST1, which turns on the third transistor M3; a low-level signal is provided by the second timing line ST2, which turns off the fourth transistor M4; a high-level signal is written to the gates of the first transistor M1 and the second transistor M2 respectively. Therefore, the gate voltage of the first transistor M1 is VGH, the gate voltage of the second transistor M2 is VGH, that is, the voltage at node N3 is Vn3 = VGH, and both the first transistor M1 and the second transistor M2 are turned on.

[0048] During the compensation phase, when the first timing line ST1 provides a low-level signal, the third transistor M3 is turned off; when the second timing line ST2 provides a high-level signal, the fourth transistor M4 is turned on. With both the second transistor M2 and the fourth transistor M4 on, the gate of the first transistor M1 discharges to the first signal terminal N1 through the fourth transistor M4. Specifically, the charge at node N3 is released until Vn3 = Vn2 + Vth2; Vn2 is the voltage at node N2, which is also the DC voltage divider voltage of R2 and R3; Vth2 is the threshold voltage of the second transistor M2. Since the first transistor M1 and the second transistor M2 are identical, Vth2 is also the threshold voltage of the first transistor M1.

[0049] Based on this, the gate voltage of the first transistor M1 is Vn3 = Vn2 + Vth2, and the threshold voltage of the first transistor M1 is Vth2. Therefore, when the first transistor M1 is operating, Vth2 is canceled out. Thus, the Vo output by the first resistor R1 is only related to the gate voltage Vn3 of the first transistor M1, and is independent of its threshold voltage. This achieves characteristic drift compensation for the first transistor M1; regardless of how the threshold voltage of the first transistor M1 drifts, it will not affect the Vo output by the first resistor R1.

[0050] Figure 7 This is a schematic diagram of another type of photodetector provided in an embodiment of the present invention. Figure 7 As shown, the photodetector includes a compensation device 10, which includes a photosensitive circuit and a compensation circuit. The photosensitive circuit includes a first transistor M1 and a first resistor R1, and the compensation circuit includes a second resistor R2, a third resistor R3, a second transistor M2, a third transistor M3, and a fourth transistor M4.

[0051] For example, M1 and M2 are phototransistors with the same aspect ratio. M1, M2, M3, and M4 are all NMOS. The first terminal of R1 is connected to the second timing line ST2. The first terminal of R2 is connected to the first terminal of R3 and connected to the first signal terminal N2. The second terminal of R2 is connected to ST2, and the second terminal of R3 is connected to the second power supply terminal V2. The gate of M1 is connected to the gate of M2, and M1 is connected between the second terminal of R1 and V2. M2 is connected between the first nodes N1 and N2. The gate of M3 is connected to the first timing line ST1, and M3 is connected between the first power supply terminal V1 and the gate of M2. The gate of M4 is connected to ST2, and M4 is connected between the gate of M2 and N1. However, the structure of the compensation device 10 is not limited to this; in other embodiments, the first terminal of R1 may also be connected to V1, and / or the second terminal of R2 may also be connected to ST2.

[0052] V1 provides a high-level signal VGH, and V2 provides a low-level signal VGL. ST1 provides a first pulse signal, ST2 provides a second pulse signal, and ST3 provides a third pulse signal. If the pulse signal is input to the gate of the transistor, the pulse signal includes a valid pulse and an invalid pulse. The valid pulse can control the connected transistor to turn on, and the invalid pulse can control the connected transistor to turn off. When the transistor is an NMOS, the valid pulse is a high-level signal.

[0053] like Figure 7 As shown, the photodetector also includes at least a third timing line ST3, transistors M5 to M22, resistors R4 to R6, and capacitors C1 to C2. The specific connection relationships between these structures are illustrated in the diagram and will not be elaborated upon here. The gate of M4 is connected to ST2, and the gate of M9 is connected to ST3. The second pulse signal of ST2 and the third pulse signal of ST3 are different, and they have a time difference. Specifically, the effective pulses of ST2 and ST3 do not overlap, and there is a time difference between them, that is, M4 and M9 are turned on in a time-division manner.

[0054] The working process of a photodetector is as follows:

[0055] During the charging phase, a high-level signal is provided by the first timing line ST1, which turns on the third transistor M3; a low-level signal is provided by the second timing line ST2, which turns off the fourth transistor M4; and a high-level signal is written to node N3 at the first power supply terminal V1. Therefore, the gate voltage of the first transistor M1 is VGH, the gate voltage of the second transistor M2 is VGH, and the voltage at node N3 is Vn3 = VGH, thus turning on both the first transistor M1 and the second transistor M2.

[0056] During the compensation phase, when the first timing line ST1 provides a low-level signal, the third transistor M3 is turned off; when the second timing line ST2 provides a high-level signal, the fourth transistor M4 is turned on. With both the second transistor M2 and the fourth transistor M4 on, the gate of the first transistor M1 discharges to the first signal terminal N1 through the fourth transistor M4. Specifically, the charge at node N3 is released until Vn3 = Vn2 + Vth2; Vn2 is the voltage at node N2, which is also the DC voltage divider voltage of R2 and R3; Vth2 is the threshold voltage of the second transistor M2. Since the first transistor M1 and the second transistor M2 are identical, Vth2 is also the threshold voltage of the first transistor M1. The compensation phase is an adaptive phase for the gate of the first transistor M1.

[0057] Following the compensation phase, there is also a voltage divider phase. During the voltage divider phase, ST2 maintains a high-level output signal, and M4 remains on; ST2 also provides a high-level signal to R1, so R1 begins voltage divider; M1 turns off itself, and the gate voltage of M1 remains unchanged.

[0058] When ST2 switches from a high level signal to a low level, M4 is turned off, and the voltage divider stage ends.

[0059] Figure 8 This is a comparative diagram of photodetectors with and without compensation circuits. For example... Figure 8 As shown, the horizontal axis represents time, and the vertical axis represents voltage. S11 is a solid line, representing the gate voltage of phototransistor M1 in a photodetector with compensation circuitry; S21 is a dashed line, representing the gate voltage of phototransistor M1 in a photodetector without compensation circuitry. M1 experiences characteristic drift due to illumination, for example, the gate voltage of phototransistor M1 increases. In a photodetector with compensation circuitry, the gate voltage of phototransistor M1 is reduced by the compensation of the second transistor M2, thus offsetting the increase in gate voltage caused by illumination. S11 and S21 overlap.

[0060] S12 is a solid line, representing the change of the voltage value Vo in the photodetector with compensation circuitry over time. S22 is a dashed line, representing the theoretical voltage value Vo in the photodetector. In a photodetector with compensation circuitry, if the gate voltage of the phototransistor M1 is compensated, its output voltage division value Vo will gradually approach the theoretical voltage value of Vo after compensation. S12 and S22 have an overlapping portion.

[0061] The simulation results show that after using the compensation circuit, the final voltage divider Vo gradually approaches the theoretical voltage value of Vo as the compensation time increases. Therefore, adding the compensation circuit does not affect the output voltage divider.

[0062] Based on the same inventive concept, embodiments of the present invention also provide a display device, including a photodetector as described in any of the above embodiments, the photodetector being used to detect ambient light.

[0063] In this embodiment, the display device can be an organic light-emitting display device or a micro LED display device, but is not limited to these. The display device can be any type of display device with adjustable screen brightness. The photosensor is used to detect ambient light and determine the illumination level. The display device adjusts the screen brightness according to the illumination level provided by the photosensor to protect the human eye and improve the display effect.

[0064] Figure 9 This is a schematic diagram of a display device provided in an embodiment of the present invention. The display device 100 can be a smartphone, tablet computer, or the like. It is understood that the above embodiments only provide some examples and structures of the photodetector; the photodetector also includes other structures, which will not be described in detail here.

[0065] The display device provided in this embodiment includes a photodetector containing a compensation circuit. The compensation circuit can compensate for the transistor characteristic drift caused by illumination, thereby solving the output voltage offset problem.

[0066] It should be understood that the various forms of processes shown above can be used, with steps reordered, added, or deleted. For example, the steps described in this invention can be executed in parallel, sequentially, or in different orders, as long as the desired result of the technical solution of this invention can be achieved, and this is not limited herein.

[0067] The specific embodiments described above do not constitute a limitation on the scope of protection of this invention. Those skilled in the art should understand that various modifications, combinations, sub-combinations, and substitutions can be made according to design requirements and other factors. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this invention should be included within the scope of protection of this invention.

Claims

1. A photodetector, characterized in that, include: Photosensitive circuit and compensation circuit; The photosensitive circuit includes a first transistor, which is a photosensitive transistor; The compensation circuit is electrically connected to the gate of the first transistor and is used to perform threshold compensation on the gate of the first transistor. The compensation circuit includes a charging unit, a discharging unit, and a compensation unit; The compensation unit includes a second transistor, which is the same phototransistor as the first transistor. The gate of the second transistor is connected to the gate of the first transistor, and the second transistor is connected between the first node and the first signal terminal. The charging unit is connected between the first power supply terminal and the gate of the second transistor; The discharge unit is connected between the gate of the second transistor and the first node.

2. The photodetector according to claim 1, characterized in that, The aspect ratio of the second transistor is the same as that of the first transistor.

3. The photodetector according to claim 1, characterized in that, The charging unit includes a third transistor, the gate of which is connected to a first timing line; The discharge unit includes a fourth transistor, the gate of which is connected to a second timing line.

4. The photodetector according to claim 3, characterized in that, Both the third transistor and the fourth transistor are NMOS.

5. The photodetector according to claim 1, characterized in that, The compensation circuit also includes a voltage divider unit; The voltage divider unit includes a second resistor and a third resistor. The first end of the second resistor and the first end of the third resistor are connected to the first signal terminal. The second end of the second resistor is connected to the second signal terminal. The second end of the third resistor is connected to the second power supply terminal.

6. The photodetector according to claim 5, characterized in that, The second signal terminal is connected to the second timing line; or, the second signal terminal is connected to the first power supply terminal.

7. The photodetector according to claim 3, characterized in that, The photodetector includes a charging phase and a compensation phase; During the charging phase, the third transistor is turned on, causing the signal at the first power supply terminal to be written into the gate of the first transistor. During the compensation phase, the second transistor and the fourth transistor are turned on, causing the gate of the first transistor to discharge to the first signal terminal through the fourth transistor.

8. The photodetector according to claim 1, characterized in that, The photosensitive circuit further includes a first resistor, a first end of which is connected to a third signal terminal, and a first transistor is connected between a second end of the first resistor and a second power supply terminal.

9. The photodetector according to claim 8, characterized in that, The third signal terminal is connected to the second timing line; or, the third signal terminal is connected to the first power supply terminal.

10. The photodetector according to claim 5 or 9, characterized in that, The first power supply terminal provides a high-potential signal, and the second power supply terminal provides a low-potential signal.

11. The photodetector according to claim 8, characterized in that, The second end of the first resistor is also connected to the subsequent circuit.

12. A display device, characterized in that, include: The photodetector as described in any one of claims 1-11, wherein the photodetector is used to detect ambient light.

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