CN115900938A - Optical detector and display device - Google Patents

Abstract

The invention discloses a light detector and a display device. The light detector includes: a light sensing circuit and a compensation circuit; the photosensitive circuit comprises a first transistor, and the first transistor is a photosensitive transistor; the compensation circuit is electrically connected with the grid electrode of the first transistor and used for carrying out threshold value compensation on the grid electrode of the first transistor. In the invention, the photosensitive circuit comprises a first transistor which is a photosensitive transistor and is easy to generate characteristic drift under long-time illumination; the compensation circuit is electrically connected with the grid electrode of the first transistor and used for carrying out threshold value compensation on the grid electrode of the first transistor, solving the characteristic drift problem of the first transistor caused by illumination, and improving the stability of the first transistor so as to improve the detection precision of the optical detector.

Description

Optical detector and display device

Technical Field

The invention relates to the technical field of optical detection, in particular to an optical detector and display equipment.

Background

With the rapid development of display devices, people rely on display devices more and more. When the display device is used for a long time, the brightness of ambient light may change, and if the brightness of the display screen cannot be adjusted in time, the eyesight of a user is damaged or a displayed picture is unclear.

Currently, a light detector is integrated in a display device, and the light detector can detect ambient light. However, in the conventional photo detector, the transistor may have characteristic deviation, which affects the detection accuracy.

Disclosure of Invention

The invention provides a light detector and a display device, which aim to solve the problem of transistor characteristic deviation in the existing light detector.

According to an aspect of the present invention, there is provided a photodetector including: a light sensing circuit and a compensation circuit;

the photosensitive circuit comprises a first transistor, and the first transistor is a photosensitive transistor;

the compensation circuit is electrically connected with the grid electrode of the first transistor and used for carrying out threshold compensation on the grid electrode of the first transistor.

According to another aspect of the present invention, there is provided a display device including: a light detector as described above for detecting ambient light.

In the invention, the photosensitive circuit comprises a first transistor which is a phototransistor and is easy to generate characteristic drift under long-time illumination; the compensation circuit is electrically connected with the grid electrode of the first transistor and used for carrying out threshold value compensation on the grid electrode of the first transistor, solving the characteristic drift problem of the first transistor caused by illumination, and improving the stability of the first transistor so as to improve the detection precision of the optical detector.

It should be understood that the statements in this section are not intended to identify key or critical features of the embodiments of the present invention, nor are they intended to limit the scope of the invention. Other features of the present invention will become apparent from the following description.

Drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings required to be used in the description of the embodiments are briefly introduced below, and it is obvious that the drawings in the description below are only some embodiments of the present invention, and it is obvious for those skilled in the art that other drawings can be obtained according to the drawings without creative efforts.

FIG. 1 is a schematic diagram of a light detector provided by an embodiment of the present invention;

FIG. 2 is a schematic view of another photodetector provided by an embodiment of the present invention;

FIG. 3 is a schematic diagram of another optical detector provided by an embodiment of the present invention;

FIG. 4 is a schematic diagram of another optical detector provided by an embodiment of the invention;

FIG. 5 is a schematic diagram of another light detector provided by an embodiment of the present invention;

FIG. 6 is a schematic diagram of another optical detector provided by an embodiment of the invention;

FIG. 7 is a schematic diagram of another optical detector provided by an embodiment of the invention;

FIG. 8 is a comparative schematic of a photodetector with and without a compensation circuit;

fig. 9 is a schematic diagram of a display device according to an embodiment of the present invention.

Detailed Description

In order to make the technical solutions of the present invention better understood, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be obtained by a person skilled in the art without making any creative effort based on the embodiments in the present invention, shall fall within the protection scope of the present invention.

It should be noted that the terms "first," "second," and the like in the description and claims of the present invention and in the drawings described above are used for distinguishing between similar elements and not necessarily for describing a particular sequential or chronological order. It is to be understood that the data so used is interchangeable under appropriate circumstances such that the embodiments of the invention described herein are capable of operation in sequences other than those illustrated or described herein. Furthermore, the terms "comprises," "comprising," and "having," and any variations thereof, are intended to cover a non-exclusive inclusion, such that a process, method, system, article, or apparatus that comprises a list of steps or elements is not necessarily limited to those steps or elements expressly listed, but may include other steps or elements not expressly listed or inherent to such process, method, article, or apparatus.

Fig. 1 is a schematic diagram of a light detector provided in an embodiment of the present invention, where the light detector provided in this embodiment may be suitable for detecting ambient light, and the light detector may be integrated in any display device for sensing the intensity of light in the surrounding environment, for example, integrated in a smart phone, so that the smart phone detects the ambient light and adjusts the brightness of the display screen accordingly. As shown in fig. 1, the photodetector includes: a light sensing circuit 11 and a compensation circuit 12; the light sensing circuit 11 includes a first transistor M1, and the first transistor M1 is a phototransistor; the compensation circuit 12 is electrically connected to the gate of the first transistor M1, and is configured to perform threshold compensation on the gate of the first transistor M1.

In this embodiment, the light detector includes a light sensing circuit 11, the light sensing circuit 11 is electrically connected to a compensation circuit 12, and the light sensing circuit 11 senses a light signal under illumination and generates and outputs an electrical signal under the driving of the compensation circuit 12. The light sensing circuit 11 includes a first transistor M1, and the first transistor M1 is a phototransistor. The phototransistor is also called as a phototransistor and is a semiconductor phototransistor device manufactured by utilizing the photoelectric effect principle of semiconductor materials, the appearance of the phototransistor is mainly characterized in that a light-sensitive window is arranged on a tube shell, the light-sensitive window is not shielded and can be irradiated by light, the phototransistor induces light signals through the light-sensitive window and generates electric signals capable of representing the light signals to be output, the light signals are used for representing the influence of light on the phototransistor, and the output electric signals are correspondingly changed when the light on the phototransistor is changed.

The photodetector further includes a compensation circuit 12, the compensation circuit 12 is electrically connected to the light sensing circuit 11, wherein the compensation circuit 12 is electrically connected to a gate of the first transistor M1 in the light sensing circuit 11, and the compensation circuit 12 is configured 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 the optical signal. 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, the first transistor M1 generates and outputs an electrical signal representing the influence of light, and the electrical signal is a current flowing through the first transistor M1, and it can be understood that the change of light received by the first transistor M1 affects the corresponding change of the current flowing through the first transistor M1.

The phototransistor is used as a light sensor to characterize the effect of light, but the phototransistor is susceptible to light induced characteristic drift after long time light exposure. For example, the threshold voltage of the phototransistor is shifted, which affects the stability of the phototransistor, so that the output electrical signal of the phototransistor is shifted, thereby affecting the detection accuracy of the photodetector. Therefore, the gate of the first transistor M1 has a problem of threshold characteristic shift caused by long-time illumination. In this embodiment, the compensation circuit 12 is added to the optical detector, so as to compensate for the threshold voltage drift of the first transistor M1, reduce the characteristic drift of the first transistor M1 caused by light irradiation, reduce the offset degree of the output electrical signal of the first transistor M1, improve the stability of the first transistor M1, and improve the detection accuracy of the optical detector.

The first transistor M1 is a light transistor, and the second transistor M2 is a compensation transistor, which are disposed adjacent to each other. The similar illumination conditions mean that the first transistor M1 and the second transistor M2 are illuminated at the same time, or the first transistor M1 and the second transistor M2 are not illuminated at the same time. The light-shielding layer is not provided above the first transistor M1 and the second transistor M2. The compensation circuit 12 functions to detect a characteristic (threshold voltage) drift condition of the illumination transistor and to make a compensation. The illumination transistor then outputs using the compensated gate voltage.

In the invention, the photosensitive circuit comprises a first transistor which is a photosensitive transistor and is easy to generate characteristic drift under long-time illumination; the compensation circuit is electrically connected with the grid electrode of the first transistor and used for carrying out threshold value compensation on the grid electrode of the first transistor, solving the characteristic drift problem of the first transistor caused by illumination, and improving the stability of the first transistor, thereby improving the detection precision of the optical detector.

The selectable light sensing circuit further comprises a first resistor, wherein a first end of the first resistor is connected with the third signal end, and the first transistor is connected between a second end of the first resistor and the second power supply end. The third signal end is connected with the second timing line; or, the third signal terminal is connected to the first power terminal.

Fig. 2 is a schematic diagram of another optical detector provided by the embodiment of the present invention. As shown in fig. 2, the photosensitive circuit 11 further includes a first resistor R1, and the optional third signal terminal is connected to the first power terminal V1, such that the first terminal of the first resistor R1 is connected to the first power terminal V1, and the first transistor M1 is connected between the second terminal of the first resistor R1 and the second power terminal V2. The second end of the first resistor R1 outputs the voltage-divided signal Vo. The first transistor M1 may be selected to be NMOS. The optional first power source terminal V1 supplies a constant high-level signal, and the second power source terminal V2 supplies a constant low-level signal. In other embodiments, the first transistor may also be selected to be PMOS, which is not specifically exemplified.

Before compensation, the first transistor M1 is affected by illumination to cause characteristic drift, and then the divided voltage signal output by the second end of the first resistor R1 is shifted, resulting in poor detection accuracy of the light detector. After the compensation circuit 12 compensates the threshold voltage drift of the first transistor M1, the characteristic drift caused by the illumination of the first transistor M1 can be reduced, and then the offset of the divided voltage signal Vo output by the second end of the first resistor R1 is compensated, so that the stability of the first transistor M1 can be improved, and the detection accuracy of the optical detector can be improved.

The second end of the optional first resistor R1 is also connected with a post-stage circuit. The voltage-dividing signal Vo output by the first resistor R1 is transmitted to the rear-stage circuit, and the rear-stage circuit analyzes and processes the Vo signal, so that the detection of ambient light can be realized, and the effect of sensing the intensity of light in the surrounding environment is achieved.

The selectable compensation circuit comprises a charging unit, a discharging unit and a compensation unit; the compensation unit comprises a second transistor, the second transistor is a photosensitive transistor same as the first transistor, the grid electrode of the second transistor is connected with the grid electrode of the first transistor, and the second transistor is connected between a first node N1 and a first signal end N2; the charging unit is connected between a 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.

Fig. 3 is a schematic diagram of another optical detector provided by the embodiment of the present invention. As shown in fig. 3, 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, the second transistor M2 is a phototransistor identical to the first transistor M1, a gate of the second transistor M2 is connected to a 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 discharge unit 14 is connected between the gate of the second transistor M2 and the first node N1.

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

The compensation unit 15 includes a second transistor M2, the second transistor M2 is a phototransistor identical to the first transistor M1, a gate of the second transistor M2 is connected to a 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 implement threshold compensation on the gate of the first transistor M1. Specifically, the second transistor M2 is a phototransistor identical to the first transistor M1, and therefore the illumination condition of the second transistor M2 is similar to that of the first transistor M1, so that it can be ensured that the characteristic drift degree of the second transistor M2 is similar to that of the first transistor M1, and then the characteristic drift of the first transistor M1 can be compensated through the second transistor M2. The first transistor M1 and the second transistor M2 may be selected to be the same NMOS, but are not limited to NMOS, and may be selected to be PMOS in other embodiments.

The width-to-length ratio of the optional second transistor M2 is the same as the width-to-length ratio of the first transistor M1. The second transistor M2 is turned on or off in synchronization with the first transistor M1. Under the same illumination, the second transistor M2 and the first transistor M1 are illuminated under the same condition, so that the characteristic drift degree of the second transistor M2 and the first transistor M1 can be ensured to be almost consistent, and the characteristic drift of the first transistor M1 can be compensated through the second transistor M2.

The selectable charging unit comprises a third transistor, and the grid electrode of the third transistor is connected with the first timing line; the discharge unit includes a fourth transistor, and a gate of the fourth transistor is connected to the second timing line. Optionally, the third transistor and the fourth transistor are both NMOS.

Fig. 4 is a schematic diagram of another optical detector provided by the embodiment of the present invention. As shown in fig. 4, the charging unit 13 includes a third transistor M3, a gate of the third transistor M3 is connected to the first timing line ST1, the third transistor M3 is connected between the first power terminal V1 and the gate of the second transistor M2, and the third transistor M3 is selectively turned on under the control of the first timing line ST 1. The discharge unit 14 includes a fourth transistor M4, a gate of the fourth transistor M4 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, and the fourth transistor M4 is selectively turned on under the control of the second timing line ST2.

The third transistor M3 and the fourth transistor M4 may be both NMOS. In other embodiments, the third transistor may be selected to be PMOS, and/or the fourth transistor may be selected to be PMOS.

Taking the NMOS shown in fig. 4 as an example, the third transistor M3 may be turned on by the first timing line ST1 outputting a high level signal, and the third transistor M3 may be turned off by the first timing line ST1 outputting a low level signal; when the third transistor M3 is turned on, an electric signal of the first power source terminal V1 is written into the gate of the second transistor M2. The second timing line ST2 outputs a high level signal to turn on the fourth transistor M4, and the second timing line ST2 outputs a low level signal to turn off the fourth transistor M4; when the fourth transistor M4 is turned on, the gate of the second transistor M2 is discharged to the first node N1.

The optional compensation circuit further comprises a voltage division unit; the voltage division unit comprises a second resistor and a third resistor, wherein the first end of the second resistor is connected with the first end of the third resistor and is connected with the first signal end, the second end of the second resistor is connected with the second signal end, and the second end of the third resistor is connected with the second power supply end. The selectable second signal end is connected with the second timing line; or, the second signal terminal is connected to the first power terminal. The optional photodetector comprises a charging phase and a compensation phase; in the charging stage, the third transistor is turned on, so that the signal of the first power supply end is written into the grid electrode of the first transistor; in the compensation stage, the second transistor and the fourth transistor are turned on, so that the grid electrode of the first transistor discharges to the first signal end through the fourth transistor.

Fig. 5 is a schematic diagram of another optical detector provided by the embodiment of the present invention. As shown in fig. 5, the compensation circuit 12 further includes a voltage dividing unit 16; the voltage dividing unit 16 comprises a second resistor R2 and a third resistor R3, a first end of the second resistor R2 is connected with a first end of the third resistor R3 and is connected with the first signal end N2, a second end of the second resistor R2 is connected with a second signal end, and the second signal end is connected with the second timing line ST2; a second terminal of the third resistor R3 is connected to the second power supply terminal V2. The optional transistors are all NMOS. The optional first power source terminal V1 provides the high level signal VGH, and the second power source terminal V2 provides the low level signal VGL. It should be noted that the second timing line ST2 provides a stable signal during the compensation phase, and the voltage of the first signal terminal N2 is fixed during the compensation phase.

Fig. 6 is a schematic diagram of another optical detector provided by the embodiment of the present invention. The difference from fig. 5 is that the second terminal of the second resistor R2 in fig. 6 is connected to the second signal terminal, and the second signal terminal is connected to the first power terminal V1. It should be noted that, the first power terminal V1 provides a constant signal, and the voltage of the first signal terminal N2 is constant.

In this embodiment, the working process of the optical detector includes a charging phase and a compensation phase that are sequentially performed. The working principle and process of fig. 5 and 6 are the same. The description will be given only by taking the photodetector shown in fig. 5 as an example.

The operation of the light detector is as follows:

in the charging phase, the first timing line ST1 provides a high level signal, and the third transistor M3 is turned on; the second timing line ST2 provides a low level signal, and the fourth transistor M4 is turned off; the high-level signal of the first power source terminal V1 is written into the gate of the first transistor M1 and the gate of the second transistor M2, respectively. Then the gate voltage of the first transistor M1 is VGH and the gate voltage of the second transistor M2 is VGH, i.e., the voltage Vn3 of the node N3= VGH, and the first transistor M1 and the second transistor M2 are turned on.

In the compensation stage, the first timing line ST1 provides a low level signal, and the third transistor M3 is turned off; the second timing line ST2 provides a high level signal, and the fourth transistor M4 is turned on; when the second transistor M2 and the fourth transistor M4 are turned on, the gate of the first transistor M1 is discharged to the first signal terminal N1 through the fourth transistor M4. Specifically, the charge of the node N3 is released until Vn3= Vn2+ Vth2; vn2 is the voltage of the node N2 and is also the direct-current voltage division 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 the same, vth2 is the same as the threshold voltage of the first transistor M1.

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, so that Vth2 is cancelled when the first transistor M1 operates, and Vo output by the first resistor R1 is only related to the gate voltage Vn3 of the first transistor M1 and is not related to the threshold voltage of the first transistor M1. Therefore, the characteristic drift compensation of the first transistor M1 is realized, and the Vo output by the first resistor R1 is not influenced no matter how the threshold voltage of the first transistor M1 drifts.

Fig. 7 is a schematic diagram of another optical detector provided by the embodiment of the invention. As shown in fig. 7, the light detector includes a compensation device 10, the compensation device 10 includes a light sensing circuit and a compensation circuit, the light sensing 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.

Illustratively, M1 and M2 are phototransistors having the same width-to-length ratio. M1, M2, M3 and M4 are all NMOS. The first end of R1 is connected to the second timing line ST2. The first end of R2 is connected with the first end of R3 and is connected to the first signal end N2, the second end of R2 is connected with ST2, and the second end of R3 is connected with the second power supply end V2. The grid of M1 is connected with the grid of M2, and M1 is connected between the second end 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 gates of the first power source terminals V1 and M2. The gate of M4 is connected to ST2, and M4 is connected between the gate of M2 and N1. The structure of the compensating device 10 is not limited thereto; in other embodiments, the first end of R1 may also be connected to V1, and/or the second end of R2 may also be connected to ST2.

V1 provides a high level signal VGH and V2 provides a low level signal VGL. The first pulse signal is provided by ST1, the second pulse signal is provided by ST2, the third pulse signal is provided by ST3, if the pulse signals are input to the grid electrode of the transistor, the pulse signals comprise an effective pulse and an ineffective pulse, the effective pulse can control the connected transistor to be turned on, and the ineffective pulse can control the connected transistor to be turned off. The transistor is NMOS, and the effective pulse is a high level signal.

As shown in fig. 7, the optical detector further includes at least a third timing line ST3, transistors M5 to M22, resistors R4 to R6, and capacitors C1 to C2, and the specific connection relationship between the structures is shown in the figure and is not described herein. The second pulse signal of the gate connections ST2 and ST3 of M4 and M9 and the third pulse signal of ST3 are different and have a time difference, specifically, the effective pulse of ST2 and the effective pulse of ST3 do not overlap and are separated by a time difference, that is, M4 and M9 are turned on in time division.

The working process of the light detector is as follows:

in the charging phase, the first timing line ST1 provides a high level signal, and the third transistor M3 is turned on; the second timing line ST2 provides a low level signal, and the fourth transistor M4 is turned off; the high level signal of the first power source terminal V1 is written into the node N3. Then the gate voltage of the first transistor M1 is VGH, the gate voltage of the second transistor M2 is VGH, i.e., the voltage Vn3= VGH of the node N3, and the first transistor M1 and the second transistor M2 are turned on.

In the compensation stage, the first timing line ST1 provides a low level signal, and the third transistor M3 is turned off; the second timing line ST2 provides a high level signal, and the fourth transistor M4 is turned on; the second transistor M2 and the fourth transistor M4 are turned on, and the gate of the first transistor M1 discharges to the first signal terminal N1 through the fourth transistor M4. Specifically, the charge of the node N3 is released until Vn3= Vn2+ Vth2; vn2 is the voltage of the node N2 and is also the direct-current voltage division 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 the same, vth2 is the same as the threshold voltage of the first transistor M1. The compensation phase is an adaptation phase of the gate of the first transistor M1.

After the compensation phase, a voltage division phase is also included. In the voltage division stage, ST2 keeps outputting a high level signal, and M4 keeps conducting; ST2 also provides a high level signal for R1, and then R1 starts to divide voltage; m1 is self-off and the gate voltage of M1 is unchanged.

When ST2 switches from the high level signal to the low level signal, M4 is turned off, and the voltage division phase is ended.

FIG. 8 is a schematic diagram comparing a photodetector with a compensation circuit and a photodetector without a compensation circuit. As shown in fig. 8, the abscissa is time and the ordinate is voltage. S11 is a solid line and is characterized in that the gate voltage of a photosensitive transistor M1 in the optical detector with the compensation circuit is represented; s21 is a dashed line and is characterized by the gate voltage of the phototransistor M1 in the photodetector without compensation circuit. M1 is influenced by illumination to cause characteristic drift, for example, the grid voltage of the photosensitive transistor M1 is increased, the grid voltage of the photosensitive transistor M1 in the light detector with the compensation circuit is compensated by the second transistor M2, the grid voltage of the photosensitive transistor M1 is reduced, and the grid voltage increased by the illumination of the M1 is counteracted. There is an overlap of S11 and S21.

S12 is a solid line, and is characterized by the change over time of the voltage value of Vo in the photodetector with the compensation circuit. S22 is a dashed line, characterized by the theoretical voltage value of Vo in the photo detector. In the photo detector with the compensation circuit, the gate voltage compensation is performed on the photosensitive transistor M1, and then the divided voltage value Vo output by the photosensitive transistor M gradually approaches the theoretical voltage value of Vo after the compensation. There is an overlap of S12 and S22.

As can be seen from the simulation results, after the compensation circuit is used, the final divided voltage Vo gradually approaches the theoretical voltage value of Vo along with the increase of the compensation time. Therefore, the addition of the compensation circuit does not affect the output of the divided voltage.

Based on the same inventive concept, embodiments of the present invention further provide a display device, including the light detector described in any of the above embodiments, where the light detector is configured to detect ambient light.

In this embodiment, the display device may be an organic light emitting display device or a micro LED display device, but is not limited thereto, and the display device may be any display device with adjustable screen brightness. The light detector is used for detecting ambient light and determining illumination brightness, and the display device adjusts screen brightness according to the illumination brightness provided by the light detector so as to protect human eyes and improve display effect.

Fig. 9 is a schematic diagram of a display device according to an embodiment of the present invention, and the display device 100 may be a smart phone, a tablet computer, or the like. It is understood that the above embodiments only provide some examples and structures of the optical detector, and the optical detector further includes other structures, which are not described in detail herein.

The display device provided by the embodiment, wherein the light detector comprises a compensation circuit, and the compensation circuit can compensate the transistor characteristic drift caused by illumination, so as to solve the problem of the offset of the output voltage.

It should be understood that various forms of the flows shown above, reordering, adding or deleting steps, may be used. For example, the steps described in the present invention may be executed in parallel, sequentially, or in different orders, and are not limited herein as long as the desired results of the technical solution of the present invention can be achieved.

The above-described embodiments should not be construed as limiting the scope of the invention. It should be understood by those skilled in the art that various modifications, combinations, sub-combinations and substitutions may be made, depending on design requirements and other factors. Any modification, equivalent replacement, and improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims (13)

1. A light detector, comprising: a light sensing circuit and a compensation circuit;

the photosensitive circuit comprises a first transistor, and the first transistor is a photosensitive transistor;

the compensation circuit is electrically connected with the grid electrode of the first transistor and used for carrying out threshold compensation on the grid electrode of the first transistor.

2. The light detector of claim 1, wherein the compensation circuit comprises a charging unit, a discharging unit, and a compensation unit;

the compensation unit comprises a second transistor, the second transistor is a photosensitive transistor identical to the first transistor, the grid electrode of the second transistor is connected with the grid electrode of the first transistor, and the second transistor is connected between a first node and a first signal end;

the charging unit is connected between a 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.

3. The photodetector of claim 2, wherein the width-to-length ratio of the second transistor is the same as the width-to-length ratio of the first transistor.

4. The photodetector of claim 2, wherein the charging unit comprises a third transistor, a gate of the third transistor being connected to a first timing line;

the discharge unit comprises a fourth transistor, and the grid electrode of the fourth transistor is connected with a second timing line.

5. The photodetector of claim 4, wherein the third transistor and the fourth transistor are both NMOS.

6. The light detector of claim 2, wherein the compensation circuit further comprises a voltage divider unit;

the voltage division unit comprises a second resistor and a third resistor, a first end of the second resistor is connected with a first end of the third resistor and is connected with the first signal end, a second end of the second resistor is connected with the second signal end, and a second end of the third resistor is connected with a second power supply end.

7. The optical detector of claim 6, wherein the second signal terminal is connected to a second timing line; or, the second signal terminal is connected to the first power terminal.

8. The light detector of claim 4, wherein the light detector comprises a charging phase and a compensation phase;

in the charging stage, the third transistor is turned on, so that the signal of the first power supply end is written into the grid electrode of the first transistor;

in the compensation phase, the second transistor and the fourth transistor are turned on, so that the gate of the first transistor is discharged to the first signal terminal through the fourth transistor.

9. The photodetector of claim 1, wherein the photosensitive circuit further comprises a first resistor, a first terminal of the first resistor is connected to a third signal terminal, and the first transistor is connected between a second terminal of the first resistor and a second power supply terminal.

10. The optical detector of claim 9, wherein the third signal terminal is connected to a second timing line; or, the third signal terminal is connected to the first power terminal.

11. A photodetector according to claim 6 or 10, characterized in that the first supply terminal supplies a high potential signal and the second supply terminal supplies a low potential signal.

12. The optical detector of claim 9, wherein the second terminal of the first resistor is further connected to a subsequent stage.

13. A display device, comprising: the light detector of any one of claims 1-12, for detecting ambient light.

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