Light detector and display device

Abstract

The present invention discloses a photodetector and a display device, the photodetector includes: a photosensitive circuit, a reference circuit and a driving circuit; the photosensitive circuit is electrically connected to the driving circuit, the photosensitive circuit includes a first transistor, and the first transistor is a photosensitive transistor; the reference circuit is electrically connected to the driving circuit, and is also electrically connected to the gate of the first transistor, the reference circuit is used to output a first reference signal under the drive of the driving circuit, and also drives the first transistor to output a first photoelectric signal; the driving circuit is used to adjust the first photoelectric signal through the photosensitive circuit, and adjust the first reference signal through the reference circuit, and then determine the light intensity according to the first reference signal and the first photoelectric signal. In the present invention, the driving circuit autonomously adjusts the first reference signal and the first photoelectric signal, so that the detected current can meet the current detection range of the driving circuit, so as to reduce the influence of the process environment on the current, avoid detection failure and burnout of the device, and improve the detection accuracy and device life.

Description

Technical Field

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

[0002] With the rapid development of display devices, people are becoming more and more dependent on them. When using display devices for a long time, the brightness of the ambient light may change. If the brightness of the display screen is not adjusted in time, it will cause damage to the user's eyesight or make the display image unclear.

[0003] Currently, display devices are integrated with photodetectors that can detect ambient light, but existing photodetectors are prone to failures such as detection failure or burnout. Summary of the invention

[0004] The present invention provides a light detector and a display device to solve the problem that the existing light detector fails to detect or is easy to burn out.

[0005] According to one aspect of the present invention, there is provided a photodetector, comprising: a photosensitive circuit, a reference circuit and a driving circuit;

[0006] The photosensitive circuit is electrically connected to the driving circuit, and the photosensitive circuit includes a first transistor, which is a photosensitive transistor;

[0007] The reference circuit is electrically connected to the driving circuit and is also electrically connected to the gate of the first transistor. The reference circuit is used to output a first reference signal under the drive of the driving circuit and drive the first transistor to output a first photoelectric signal.

[0008] The driving circuit is used to adjust the first photoelectric signal through the photosensing circuit and adjust the first reference signal through the reference circuit, and then determine the light intensity according to the first reference signal and the first photoelectric signal.

[0009] According to another aspect of the present invention, a display device is provided, comprising: the light detector as described above, wherein the light detector is used to detect ambient light.

[0010] In the present invention, the photosensitive circuit includes a first transistor, which is a photosensitive transistor; the reference circuit is electrically connected to the gate of the first transistor, the driving circuit adjusts the first photoelectric signal through the photosensitive circuit, and adjusts the first reference signal through the reference circuit, and determines the light intensity according to the first reference signal and the first photoelectric signal. In the present invention, the driving circuit can autonomously adjust the first reference signal and the first photoelectric signal so that the detected current can meet the current detection range of the driving circuit, thereby reducing the influence of the process environment on the current, avoiding detection failure and burning of the device, and improving the detection accuracy and device life.

[0011] It should be understood that the contents described in this section are not intended to identify the key or important features of the embodiments of the present invention, nor are they intended to limit the scope of the present invention. Other features of the present invention will become easily understood through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0013] Figure 1 is a schematic diagram of a light detector provided by an embodiment of the present invention;

[0014] Figure 2 is a schematic diagram of another light detector provided by an embodiment of the present invention;

[0015] Figure 3 is a schematic diagram of another optical detector provided by an embodiment of the present invention;

[0016] Figure 4 yes Figure 3 Timing diagram of

[0017] Figure 5 yes Figure 3 Another timing diagram of

[0018] Figure 6 is a schematic diagram of another optical detector provided by an embodiment of the present invention;

[0019] Figure 7 yes Figure 6 Timing diagram of

[0020] Figure 8 It is a schematic diagram of a display device provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0021] In order to enable those skilled in the art to better understand the scheme of the present invention, the technical scheme in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work 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 and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchanged where appropriate, so that the embodiments of the present invention described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units that are clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0023] Figure 1 is a schematic diagram of a light detector provided by an embodiment of the present invention. The light detector provided by this embodiment can be used to detect ambient light. The light detector can be integrated into any display device to sense the intensity of light in the surrounding environment. For example, it can be integrated into a smart phone to enable the smart phone to detect ambient light and adjust the brightness of the display screen accordingly. Figure 1 As shown, the photodetector includes: a photosensitive circuit 11, a reference circuit 12 and a driving circuit 13; the photosensitive circuit 11 is electrically connected to the driving circuit 13, and the photosensitive circuit 11 includes a first transistor M1, which is a photosensitive transistor; the reference circuit 12 is electrically connected to the driving circuit 13, and is also electrically connected to the gate of the first transistor M1, and the reference circuit 12 is used to output a first reference signal under the drive of the driving circuit 13, and also drives the first transistor M1 to output a first photoelectric signal; the driving circuit 13 is used to adjust the first photoelectric signal through the photosensitive circuit 11, and adjust the first reference signal through the reference circuit 12, and then determine the light intensity according to the first reference signal and the first photoelectric signal.

[0024] In this embodiment, the photodetector includes a photosensitive circuit 11, which is electrically connected to a reference circuit 12 and a driving circuit 13, respectively. The photosensitive circuit 11 senses a light signal under illumination, and generates an electrical signal under the control of the reference circuit 12 and the driving circuit 13 and transmits it to the driving circuit 13. The photosensitive circuit 11 includes a first transistor M1, which is a photosensitive transistor. A photosensitive transistor, also known as a phototransistor, is a semiconductor phototransistor device made using the principle of the photoelectric effect of semiconductor materials. The biggest feature of the appearance of a photosensitive transistor is that a photosensitive window is provided in the tube shell, and the photosensitive window is not blocked and can be illuminated by light. The photosensitive transistor senses the light signal through the photosensitive window and generates an electrical signal that can represent the light signal for output. It can be understood that the electrical signal is used to represent the influence of illumination on the photosensitive transistor. If the illumination on the photosensitive transistor changes, the output electrical signal changes accordingly.

[0025] The gate of the first transistor M1 is connected to the reference circuit 12, and the two ends of the first transistor M1 are respectively connected to the two ports of the driving circuit 13, and the first transistor M1 can sense the light signal. Based on this, the reference 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 an electrical signal representing the light signal under the drive of the driving circuit 13 and outputs it to the driving circuit 13. The electrical signal output by the first transistor M1 to the driving circuit 13 is the first photoelectric signal, and the first photoelectric signal is the current flowing through the first transistor M1. It can be understood that the change in the light received by the first transistor M1 will affect the corresponding change in the current flowing through the first transistor M1.

[0026] The photodetector further includes a reference circuit 12, which is electrically connected to the photosensitive circuit 11 and the driving circuit 13, respectively, wherein the reference circuit 12 is electrically connected to the gate of the first transistor M1 in the photosensitive circuit 11. The reference circuit 12 generates two electrical signals under the drive of the driving circuit 13, wherein one electrical signal is output to the driving circuit 13, and the electrical signal is the first reference signal output to the driving circuit 13, and the first reference signal is a current signal; and the other electrical signal is output to the photosensitive circuit 11, and the electrical signal is transmitted to the gate of the first transistor M1 to control the first transistor M1 to be turned on or off.

[0027] The photodetector also includes a driving circuit 13, which is electrically connected to the reference circuit 12 and the photosensitive circuit 11, respectively. The driving circuit 13 drives the reference circuit 12 to adjust the first reference signal, and also drives the photosensitive circuit 11 to adjust the first photoelectric signal. After adjustment, the first reference signal and the first photoelectric signal obtained by the driving circuit 13 are within the current detection range of the driving circuit 13. Based on this, the driving circuit 13 can detect the photoelectric current based on the first reference signal and the first photoelectric signal and determine the light brightness.

[0028] It should be noted that the driving circuit 13 can be an IC. The current of the photosensitive transistor in the photodetector is very different when it is illuminated and when it is not illuminated, and the current of each transistor will fluctuate due to the influence of process fluctuations, ambient temperature, etc. Usually, the channel interface of the IC has a limit on the current detection range. If the current received by the channel interface of the IC is lower than the minimum value of the current detection range, then the current is too small and may cause detection failure. If the current received by the channel interface of the IC is higher than the maximum value of the current detection range, then the current is too large and may cause the IC to burn out after being input into the IC. In this embodiment, the driving circuit 13 autonomously adjusts the first reference signal and the first photoelectric signal, so that the detected current meets the current detection range of the driving circuit 13, reduces the influence of process fluctuations, avoids detection failure and IC burning, and improves detection accuracy and device life.

[0029] The current detection range of the existing IC for the channel interface is 40mA to 300mA. If the current detected by the channel interface is greater than 300mA, the IC is likely to burn out. If the current of the channel interface is less than 40mA, it is difficult for the channel interface of the IC to detect the current signal, and the detection fails. In this embodiment, the driving circuit 13 adjusts the first reference signal output by the reference circuit 12 to be within 40mA to 300mA; and adjusts the first photoelectric signal output by the photosensitive circuit 11 to be within 40mA to 300mA.

[0030] refer to Figure 1 As shown, the optional first transistor M1 is connected between the first power supply terminal V1 and the photoelectric signal terminal S1; the driving circuit 13 is used to provide a first electrical signal to the first power supply terminal V1, and obtain a first photoelectric signal through the photoelectric signal terminal S1. In this embodiment, the gate of the first transistor M1 is connected to the reference circuit 12, the first end of the first transistor M1 is connected to the first power supply terminal V1 and the second end is connected to the photoelectric signal terminal S1. The first transistor M1 can sense the light signal.

[0031] If the first transistor M1 is an NMOS, the reference circuit 12 provides a high level signal to the gate of the first transistor M1 to turn on the first transistor M1, and the reference circuit 12 provides a low level signal to the gate of the first transistor M1 to turn off the first transistor M1. If the first transistor M1 is a PMOS, the reference circuit 12 provides a high level signal to the gate of the first transistor M1 to turn off the first transistor M1, and the reference circuit 12 provides a low level signal to the gate of the first transistor M1 to turn on the first transistor M1.

[0032] like Figure 1 The optional first transistor M1 shown is an NMOS. The reference circuit 12 provides a high-level signal to the gate of the first transistor M1 to turn on the first transistor M1. Then, under the drive of the drive circuit 13, the first transistor M1 outputs a first photoelectric signal that can represent the optical signal. The first photoelectric signal is output to the drive circuit 13 through the photoelectric signal terminal S1. It can be understood that the first photoelectric signal is a current signal flowing through the first transistor M1. The reference circuit 12 provides a low-level signal to the gate of the first transistor M1 to turn off the first transistor M1, and the first transistor M1 does not output an electrical signal to the photoelectric signal terminal S1.

[0033] In the present invention, the photosensitive circuit includes a first transistor, which is a photosensitive transistor; the reference circuit is electrically connected to the gate of the first transistor, the driving circuit adjusts the first photoelectric signal through the photosensitive circuit, and adjusts the first reference signal through the reference circuit, and determines the light intensity according to the first reference signal and the first photoelectric signal. In the present invention, the driving circuit can autonomously adjust the first reference signal and the first photoelectric signal so that the detected current can meet the current detection range of the driving circuit, thereby reducing the influence of the process environment on the current, avoiding detection failure and burning of the device, and improving the detection accuracy and device life.

[0034] Figure 2 FIG. 1 is a schematic diagram of another optical detector provided by an embodiment of the present invention. Figure 2 As shown, the optional reference circuit 12 includes a second transistor M2, which is connected between the first power supply terminal V1 and the reference signal terminal S2; the driving circuit 13 is used to provide a first electrical signal to the first power supply terminal V1, and obtain the first reference signal through the reference signal terminal S2. The optional reference circuit 12 also includes a voltage divider unit 14 and a coupling unit 15; the voltage divider unit 14 is connected between the first power supply terminal V1 and the second power supply terminal V2, and is also connected to the first voltage divider terminal N1 and the second voltage divider terminal N2 respectively, and the voltage divider unit 14 is used to provide a first voltage divider signal to the first voltage divider terminal N1, and provide a second voltage divider signal to the second voltage divider terminal N2; the first end of the coupling unit 15 is connected to the first voltage divider terminal N1, the second end is connected to the second voltage divider terminal N2, the third end is connected to the gate of the second transistor M2, and the fourth end is connected to the gate of the first transistor M1; the driving circuit 13 is used to provide a second electrical signal different from the first electrical signal to the second power supply terminal V2.

[0035] In this embodiment, the gate of the second transistor M2 is connected to the third terminal of the coupling unit 15, the first terminal of the second transistor M2 is connected to the first power supply terminal V1 and the second terminal is connected to the reference signal terminal S2. The second transistor M2 is not a photosensitive transistor and is not affected by light. If the second transistor M2 is an NMOS, the coupling unit 15 provides a high-level signal to the gate of the second transistor M2 to turn on the second transistor M2, and provides a low-level signal to turn off the second transistor M2. If the second transistor M2 is a PMOS, the reference circuit 12 provides a high-level signal to the gate of the second transistor M2 to turn off the second transistor M2, and provides a low-level signal to turn on the second transistor M2.

[0036] like Figure 2The optional second transistor M2 shown is an NMOS. The coupling unit 15 provides a high-level signal to the gate of the second transistor M2 to turn on the second transistor M2. Then, under the drive of the driving circuit 13, the second transistor M2 outputs a first reference signal, which is output to the driving circuit 13 through the reference signal terminal S2. It can be understood that the first reference signal is a current signal flowing through the second transistor M2. The coupling unit 15 provides a low-level signal to the gate of the second transistor M2 to turn off the second transistor M2, and the second transistor M2 does not output an electrical signal to the reference signal terminal S2.

[0037] The reference circuit 12 also includes a voltage divider unit 14. The voltage divider unit 14 is connected between a first power supply terminal V1 and a second power supply terminal V2. The first power supply terminal V1 provides a first electrical signal, and the second power supply terminal V2 provides a second electrical signal different from the first electrical signal. Then, the voltage divider unit 14 can divide voltages based on the different first electrical signals and second electrical signals to generate a first voltage divider signal and a second voltage divider signal. The voltage divider unit 14 is also connected to a first voltage divider terminal N1 and a second voltage divider terminal N2, respectively. Then, the first voltage divider signal generated by the voltage divider unit 14 is transmitted to the first voltage divider terminal N1, and the second voltage divider signal is transmitted to the second voltage divider terminal N2.

[0038] The reference circuit 12 further includes a coupling unit 15. A first end of the coupling unit 15 is connected to the first voltage-dividing terminal N1 to receive a first voltage-dividing signal, a second end is connected to the second voltage-dividing terminal N2 to receive a second voltage-dividing signal, a third end is connected to the gate of the second transistor M2, and a fourth end is connected to the gate of the first transistor M1. Then, driven by the first voltage-dividing signal and the second voltage-dividing signal, the coupling unit 15 generates a first control signal and provides it to the gate of the first transistor M1 to control the first transistor M1 to be turned on or off, and generates a second control signal and provides it to the gate of the second transistor M2 to control the second transistor M2 to be turned on or off.

[0039] Under the control of the coupling unit 15, the first transistor M1 is selectively turned on and provides a first photoelectric signal to the driving circuit 13 when turned on, and the second transistor M2 is selectively turned on and provides a first reference signal to the driving circuit 13 when turned on. The driving circuit 13 determines the light intensity according to the first photoelectric signal and the first reference signal.

[0040] In this embodiment, a reference circuit is newly added to the photodetector, and the driving circuit drives the photosensitive circuit and adjusts the current signal outputted by the photosensitive circuit, and also drives the reference circuit and adjusts the current signal outputted by the reference circuit, so that the current values ​​of the first photoelectric signal and the first reference signal are within the current detection range of the driving circuit. The driving circuit then determines the light brightness or light intensity based on the output currents of the photosensitive circuit and the reference circuit detected.

[0041] Figure 3FIG. 1 is a schematic diagram of another optical detector provided by an embodiment of the present invention. Figure 3 As shown, the optional voltage divider unit 14 includes a first resistor R1, a second resistor R2, a third transistor M3 and a fourth transistor M4, the third transistor M3 is a photosensitive transistor, and the fourth transistor M4 is a transistor that is not illuminated by light; the first resistor R1 is connected between the first power supply terminal V1 and the second voltage divider terminal N2; the third transistor M3 is connected between the second voltage divider terminal N2 and the second power supply terminal V2, and the gate of the third transistor M3 is connected to the first power supply terminal V1; the second resistor R2 is connected between the first power supply terminal V1 and the first voltage divider terminal N1; the fourth transistor M4 is connected between the first voltage divider terminal N1 and the second power supply terminal V2, and the gate of the fourth transistor M4 is connected to the first power supply terminal V1. The optional coupling unit 15 includes a fifth transistor M5 and a sixth transistor M6; the fifth transistor M5 is connected between the first voltage divider terminal N1 and the gate of the first transistor M1; the sixth transistor M6 is connected between the second voltage divider terminal N2 and the gate of the second transistor M2; the gate of the fifth transistor M5 and the gate of the sixth transistor M6 are commonly connected to the first timing terminal ST1; the driving circuit 13 is used to provide a first timing signal to the first timing terminal ST1. The optional coupling unit 15 also includes a first capacitor C1 and a second capacitor C2; the first capacitor C1 is connected between the second timing terminal ST2 and the gate of the first transistor M1; the second capacitor C2 is connected between the second timing terminal ST2 and the gate of the second transistor M2; the driving circuit 13 is used to provide the second timing terminal ST2 with a second timing signal different from the first timing signal.

[0042] In this embodiment, the first resistor R1 and the third transistor M3 are connected in series, and the first electrical signal provided by the first power supply terminal V1 and the second electrical signal provided by the second power supply terminal V2 are divided to generate a second divided voltage signal, and the second divided voltage signal is provided to the second divided voltage terminal N2. The second divided voltage terminal N2 is connected to the gate of the second transistor M2 through the sixth transistor M6, so when the sixth transistor M6 is turned on, the second divided voltage signal is used as the driving gate voltage of the second transistor M2.

[0043] The second resistor R2 and the fourth transistor M4 are connected in series, and divide the first electrical signal provided by the first power supply terminal V1 and the second electrical signal provided by the second power supply terminal V2 to generate a first divided voltage signal, and the first divided voltage signal is provided to the first divided voltage terminal N1. The first divided voltage terminal N1 is connected to the gate of the first transistor M1 through the fifth transistor M5, so when the fifth transistor M5 is turned on, the first divided voltage signal is used as the driving gate voltage of the first transistor M1.

[0044] It should be noted that the third transistor M3 is a photosensitive transistor. The third transistor M3 has a photosensitive window and is not blocked, so light can irradiate the photosensitive window. The third transistor M3 is affected by light and the output electrical signal can represent the light signal. It can be understood that the electrical signal is used to represent the light effect on the photosensitive transistor. When the light on the photosensitive transistor changes, the output electrical signal changes accordingly. The fourth transistor M4 is a transistor that is not illuminated by light. For example, the fourth transistor M4 is a photosensitive transistor, but its photosensitive window is blocked, so light cannot irradiate the fourth transistor M4, and the fourth transistor M4 is not affected by light; or, the fourth transistor M4 is a conventional non-photosensitive transistor, and light irradiates the fourth transistor M4 without affecting the fourth transistor M4.

[0045] As described above, the third transistor M3 and the fourth transistor M4 are different, the third transistor M3 is a photosensitive transistor, and the fourth transistor M4 is not illuminated by light, so factors such as process fluctuations, temperature, and light will affect the equivalent resistance of M3 and M4. Based on this, the voltage divider unit 14 can obtain different first voltage divider signals and second voltage divider signals by using the changed equivalent resistance to divide the voltage, and the two voltage divider signals are used as the driving gate voltages of M1 and M2 respectively.

[0046] The gate of the fifth transistor M5 and the gate of the sixth transistor M6 are commonly connected to the first timing terminal ST1, and the driving circuit 13 provides a first timing signal to the first timing terminal ST1. The first timing signal may be different in different working stages. Specifically, the first timing signal includes a valid scan signal and an invalid scan signal. The first timing signal is a valid scan signal, which can control the fifth transistor M5 and the sixth transistor M6 to be turned on at the same time; the first timing signal is an invalid scan signal, which can control the fifth transistor M5 and the sixth transistor M6 to be turned off at the same time. The fifth transistor M5 and the sixth transistor M6 can be both NMOS, then the valid scan signal of the first timing signal is a high level signal, and the invalid scan signal is a low level signal. In other embodiments, the fifth transistor and the sixth transistor can be both PMOS, then the valid scan signal of the first timing signal is a low level signal, and the invalid scan signal is a high level signal.

[0047] When the fifth transistor M5 is turned on, the first voltage-divided signal is used as the driving gate voltage of the first transistor M1 to control the first transistor M1 to be turned on or off; when the first transistor M1 is turned on, the first photoelectric signal is output to the driving circuit 13. When the sixth transistor M6 is turned on, the second voltage-divided signal is used as the driving gate voltage of the second transistor M2 to control the second transistor M2 to be turned on or off; when the second transistor M2 is turned on, the first reference signal is output to the driving circuit 13.

[0048] The coupling unit 15 also includes a first capacitor C1 and a second capacitor C2, C1 can couple the gate voltage of M1, and C2 can couple the gate voltage of M2. The first end of the first capacitor C1 is connected to the second timing terminal ST2, and the second end is connected to the gate of the first transistor M1; the first end of the second capacitor C2 is connected to the second timing terminal ST2, and the second end is connected to the gate of the second transistor M2. The driving circuit 13 provides a second timing signal different from the first timing signal to the second timing terminal ST2. The second timing signal may be different in different working stages. Specifically, the second timing signal includes a high level signal and a low level signal.

[0049] If the gate of the first transistor M1 is suspended, the second timing signal switches from a high level to a low level, and the gate voltage of the first transistor M1 is pulled down through the first capacitor C1; the second timing signal switches from a low level to a high level, and the gate voltage of the first transistor M1 is pulled up through the first capacitor C1. If the gate of the second transistor M2 is suspended, the second timing signal switches from a high level to a low level, and the gate voltage of the second transistor M2 is pulled down through the second capacitor C2; the second timing signal switches from a low level to a high level, and the gate voltage of the second transistor M2 is pulled up through the second capacitor C2.

[0050] It should be noted that the first voltage-dividing signal and the second voltage-dividing signal generated by the voltage-dividing unit 14 may be small, so C1 and C2 are required to couple and lift. The on-off state of M5 determines whether the gate of M1 is suspended, and the on-off state of M6 determines whether the gate of M2 is suspended. When ST1 controls M5 and M6 to turn on, the gates of M1 and M2 are not suspended, the electrical signal of the first voltage-dividing terminal N1 directly controls the on-off state of M1, and the electrical signal of the second voltage-dividing terminal N2 directly controls the on-off state of M2; when ST1 controls M5 and M6 to turn off, the gates of M1 and M2 are suspended, and the gate voltage of M1 can be coupled by C1, and the gate voltage of M2 can be coupled by C2.

[0051] The width-to-length ratio of the third transistor M3 can be the same as that of the first transistor M1. The third transistor M3 and the first transistor M1 are both photosensitive transistors, so the width-to-length ratio of the third transistor M3 is the same as that of the first transistor M1, and the same process can be used to manufacture, which reduces the difficulty of process manufacturing. However, in other embodiments, the third transistor can also be different from the first transistor.

[0052] Figure 4 yes Figure 3Timing diagram of the invention. The optional photodetector includes a first output stage; in the first output stage, the fifth transistor M5 and the sixth transistor M6 are turned on. The optional photodetector includes a second output stage; in the second output stage, the fifth transistor M5 and the sixth transistor M6 are turned off, and the gate voltage of the first transistor M1 and the gate voltage of the second transistor M2 are coupled to turn on the first transistor M1 and the second transistor M2. The optional photodetector includes a turn-off stage; in the turn-off stage, the gate voltage of the first transistor M1 and the gate voltage of the second transistor M2 are coupled to turn off the first transistor M1 and the second transistor M2. In the turn-off stage, the fifth transistor M5 and the sixth transistor M6 are turned off. The optional first power supply terminal V1 provides a high level signal H, and the second power supply terminal V2 provides a low level signal L.

[0053] The optional photosensitive circuit 11 and the reference circuit 12 both include transistors, and the transistors are all NMOS. The newly added reference circuit 12 includes transistors, and the manufacturing process is mature and not limited by the substrate. For example, it can be made on various glass panels. It should be noted that the transistors in the photosensitive circuit and the reference circuit are not limited to NMOS. Those skilled in the art can also reasonably design transistors according to product requirements, such as CMOS or PMOS.

[0054] like Figure 4 As shown, the working phase of the light detector includes at least t1 to t5, which are as follows:

[0055] In the t1 phase, the current ratio of M1 and M2 is adjusted. Specifically, ST1 and ST2 provide low-level signals, M5 and M6 are turned off; V1 provides a constant high-level signal H, V2 provides a constant low-level signal L, R1, R2, M3 and M4 are divided, wherein M3 can be illuminated, M4 is not illuminated, the illuminated M3 is divided to output a second divided voltage signal, and the unilluminated M4 is divided to output a first divided voltage signal; when M3 is illuminated, M1 is also illuminated; at this time, reducing the gate voltage of M2 can correspondingly reduce the Ids current of M2, so that the current ratio of M1 and M2 is further amplified, or increasing the gate voltage of M2 can correspondingly increase the Ids current of M2, so that the current ratio of M1 and M2 is reduced. The reason why the ratio needs to be adjusted is that when Vgs=25V, Vds=25V, the current ratio of the bright and dark states is relatively stable, but the ratio is small and the IC is not easy to detect it. In this case, adjusting and amplifying the ratio can enable the IC to detect the photoelectric current. Alternatively, when Vgs and Vds are not around 25V, the current ratio of the bright and dark states is unstable and it is very easy to exceed the current detection range and burn the IC. In this case, adjusting and reducing the ratio can enable the photoelectric current to meet the IC current detection range.

[0056] In the t2 stage, ST1 provides a high-level signal, M5 and M6 are turned on; ST2 maintains a low-level signal, V1 provides a constant high-level signal, and V2 provides a constant low-level signal; the illuminated M3 divides the voltage to output the second divided signal and outputs it to the gate of M2, and the unilluminated M4 divides the voltage to output the first divided signal and outputs it to the gate of M1. The t2 stage is the first output stage, M5 and M6 are turned on, providing a driving gate voltage to the gate of M1 and a driving gate voltage to the gate of M2.

[0057] In the t3 phase, ST1 provides a low level signal, M5 and M6 are turned off; ST2 maintains a low level signal, V1 provides a constant high level signal, and V2 provides a constant low level signal; the gate of M2 is suspended and maintained as the second voltage division signal, and the gate of M1 is suspended and maintained as the first voltage division signal.

[0058] In the t4 stage, ST1 provides a low-level signal, and M5 and M6 are turned off; V1 provides a constant high-level signal, and V2 provides a constant low-level signal; ST2 switches from a low-level signal to a high-level signal, and the high-level signal of ST2 raises the gate voltage of M1 through C1 coupling to make it higher than the first voltage-divided signal, then M1 is turned on, and M1 outputs the first photoelectric signal to the drive circuit 13; at the same time, the high-level signal of ST2 raises the gate voltage of M2 through C2 coupling to make it higher than the second voltage-divided signal, then M2 is turned on, and M2 outputs the first reference signal to the drive circuit 13. The t4 stage is the second output stage, M5 and M6 are turned off, M1 and M2 are turned on, M1 implements current output to output the first photoelectric signal to the drive circuit 13, and M2 implements current output to output the first reference signal to the drive circuit 13, and at this time, the first photoelectric signal and the first reference signal are both within the current detection range of the drive circuit 13.

[0059] In the t5 stage, ST1 provides a low-level signal, M5 and M6 are turned off, the gate of M1 is suspended and the gate of M2 is suspended; V1 provides a constant high-level signal, and V2 provides a constant low-level signal; ST2 switches from a high-level signal to a low-level signal, and the low-level signal of ST2 pulls down the gate voltage of M1 through C1 coupling, turning M1 off; at the same time, the low-level signal of ST2 pulls down the gate voltage of M2 through C2 coupling, turning M2 off. The t5 stage is the shutdown stage, and the output of M1 and M2 ends.

[0060] Figure 5 yes Figure 3 Another timing diagram of Figure 4The difference is that the optional off stage includes a discharge stage; in the discharge stage, the fifth transistor M5 and the sixth transistor M6 are turned on to discharge the gate of the first transistor M1 and the gate of the second transistor M2. The start time of the optional discharge stage is later than the start time of the off stage; the end time of the discharge stage is equal to or earlier than the end time of the off stage. The optional first power supply terminal V1 provides a low level signal in the discharge stage and a high level signal in other stages; the second power supply terminal V2 provides a low level signal. In this embodiment, the drive circuit 13 provides high and low level signals to the first power supply terminal V1. Specifically, the optional drive circuit 13 provides a low level signal to the first power supply terminal V1 in the discharge stage, and the drive circuit 13 provides a high level signal to the first power supply terminal V1 in other stages other than the discharge stage. The drive circuit 13 provides a constant low level signal to the second power supply terminal V2.

[0061] like Figure 5 As shown, the working phase of the light detector includes at least t1 to t5, which are as follows:

[0062] During the phase t1 , ST1 and ST2 provide low-level signals, V1 provides a high-level signal H, and V2 provides a constant low-level signal L.

[0063] In the t2 phase, ST1 provides a high level signal, ST2 maintains a low level signal, V1 provides a high level signal, and V2 provides a constant low level signal. The t2 phase is the first output phase.

[0064] In the t3 phase, ST1 provides a low level signal, ST2 maintains a low level signal, V1 provides a high level signal, and V2 provides a constant low level signal.

[0065] In the t4 phase, ST1 provides a low level signal, V1 provides a high level signal, V2 provides a constant low level signal, and ST2 switches from a low level signal to a high level signal. The t4 phase is the second output phase.

[0066] Figure 5 The working process of t1~t4 Figure 4 The working process of t1 to t4 is the same and will not be repeated here.

[0067] Figure 5 The working process of T5 Figure 4 The working process of t5 is different. Figure 5 As shown, the t5 stage includes the t50 sub-stage and other sub-stages.

[0068] In the other sub-stages except the t50 sub-stage in the t5 stage, ST1 provides a low-level signal, and M5 and M6 are turned off; ST2 is a low-level signal, and the low-level signal of ST2 pulls down the gate voltage of M1 through C1 coupling, so that M1 is turned off; at the same time, the low-level signal of ST2 pulls down the gate voltage of M2 through C2 coupling, so that M2 is turned off. V1 can provide a low-level signal or a high-level signal, and V2 provides a constant low-level signal. The t5 stage is the shutdown stage, and the output of M1 and M2 ends.

[0069] In the t50 sub-stage, V1 provides a low-level signal, and V2 provides a constant low-level signal, then M3 and M4 are turned off, and N1 and N2 are suspended; ST2 maintains a low-level signal, M1 and M2 are turned off; ST1 provides a high-level signal, M5 and M6 are turned on; the gate voltage of M1 is discharged through M5, and the gate voltage of M2 is discharged through M6. The t50 sub-stage is the discharge stage, the gate of the turned-off M1 is discharged through M5, and the gate of the turned-off M2 is discharged through M6. In the discharge stage, the gates of M1 and M2 are discharged to zero, which can prevent the characteristics of M1 and M2 from drifting.

[0070] In this embodiment, a reference circuit is newly added to the photodetector, and the driving circuit drives the photosensitive circuit and adjusts the current signal outputted by the photosensitive circuit, and also drives the reference circuit and adjusts the current signal outputted by the reference circuit, so that the current values ​​of the first photoelectric signal and the first reference signal are within the current detection range of the driving circuit. The driving circuit then determines the light brightness or light intensity based on the output currents of the photosensitive circuit and the reference circuit detected.

[0071] Figure 6 is a schematic diagram of another optical detector provided by an embodiment of the present invention. Figure 3 The difference is that, Figure 6 The coupling unit 15 shown does not include the first capacitor C1 and the second capacitor C2. Then the first voltage-divided signal of N1 is used as the gate voltage for driving M1, and the second voltage-divided signal of N2 is used as the gate voltage for driving M2.

[0072] Figure 7 yes Figure 6 Timing diagram of Figure 4 or Figure 5 The difference is that the optional light detector includes a first output stage; in the first output stage, the fifth transistor M5 and the sixth transistor M6 are turned on, and the first transistor M1 and the second transistor M2 are turned on. The optional first power supply terminal V1 provides a high level signal H, and the second power supply terminal V2 provides a low level signal L. The optional photosensitive circuit 11 and the reference circuit 12 both include transistors, and the transistors are all NMOS.

[0073] like Figure 7 As shown, the working phase of the light detector includes at least t1 to t3, which are as follows:

[0074] In the t1 phase, the current ratio of M1 and M2 is adjusted. Specifically, ST1 provides a low-level signal, M5 and M6 are turned off; V1 provides a high-level signal H, V2 provides a constant low-level signal L, R1, R2, M3 and M4 divide the voltage, the illuminated M3 divides the voltage to output the second divided voltage signal, and the unilluminated M4 divides the voltage to output the first divided voltage signal.

[0075] In the t2 stage, ST1 provides a high-level signal, M5 and M6 are turned on; V1 provides a high-level signal, and V2 provides a constant low-level signal; the illuminated M3 divides the voltage to output the second divided voltage signal and outputs it to the gate of M2, turning M2 on; the unilluminated M4 divides the voltage to output the first divided voltage signal and outputs it to the gate of M1, turning M1 on. The t2 stage is the first output stage, M5 and M6 are turned on, providing a driving gate voltage to the gate of M1, and providing a driving gate voltage to the gate of M2. M1 and M2 are turned on, M1 realizes current output to output the first photoelectric signal to the drive circuit 13, and M2 realizes current output to output the first reference signal to the drive circuit 13. At this time, the first photoelectric signal and the first reference signal are both within the current detection range of the drive circuit 13.

[0076] In the t3 phase, V1 provides a low-level signal, and V2 provides a constant low-level signal, turning off M1 and M2; ST1 provides a low-level signal, turning off M5 and M6. The t3 phase is the turn-off phase, and the output of M1 and M2 ends.

[0077] In this embodiment, a reference circuit is newly added to the photodetector, and the driving circuit drives the photosensitive circuit and adjusts the current signal outputted by the photosensitive circuit, and also drives the reference circuit and adjusts the current signal outputted by the reference circuit, so that the current values ​​of the first photoelectric signal and the first reference signal are within the current detection range of the driving circuit. The driving circuit then determines the light brightness or light intensity based on the output currents of the photosensitive circuit and the reference circuit detected.

[0078] Based on the same inventive concept, an embodiment of the present invention further provides a display device, comprising the light detector as described in any of the above embodiments, wherein the light detector is used to detect ambient light.

[0079] 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. The display device may be any display device with adjustable screen brightness. The light detector is used to detect ambient light and determine the light brightness. The display device adjusts the screen brightness according to the light brightness provided by the light detector to protect human eyes and improve the display effect.

[0080] Figure 81 is a schematic diagram of a display device provided by an embodiment of the present invention, and the display device 100 may be a smart phone, a tablet computer, etc. It can be understood that the above embodiments only provide some examples and structures of the light detector, and the light detector also includes other structures, which will not be described one by one here.

[0081] It should be understood that the various forms of processes shown above can be used to reorder, add or delete steps. For example, the steps described in the present invention can be executed in parallel, sequentially or in different orders, as long as the desired results of the technical solution of the present invention can be achieved, and this document does not limit this.

[0082] The above specific implementations do not constitute a limitation on the protection scope of the present invention. It should be understood by those skilled in the art that various modifications, combinations, sub-combinations and substitutions can be made according to design requirements and other factors. Any modification, equivalent substitution and improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A light detector, characterized in that: include: Photosensitive circuit, reference circuit and driving circuit; The photosensitive circuit is electrically connected to the driving circuit, and the photosensitive circuit includes a first transistor, which is a photosensitive transistor; The reference circuit is electrically connected to the driving circuit and is also electrically connected to the gate of the first transistor. The reference circuit is used to output a first reference signal under the drive of the driving circuit and drive the first transistor to output a first photoelectric signal. The driving circuit is used to adjust the first photoelectric signal through the photosensitive circuit, and adjust the first reference signal through the reference circuit, and then determine the light intensity according to the first reference signal and the first photoelectric signal; The reference circuit includes a second transistor connected between the first power supply terminal and the reference signal terminal; The driving circuit is used to provide a first electrical signal to the first power supply terminal, and obtain the first reference signal through the reference signal terminal; The reference circuit also includes a voltage dividing unit and a coupling unit; The voltage dividing unit is connected between the first power supply terminal and the second power supply terminal, and is also connected to the first voltage dividing terminal and the second voltage dividing terminal respectively, and the voltage dividing unit is used to provide a first voltage dividing signal to the first voltage dividing terminal and provide a second voltage dividing signal to the second voltage dividing terminal; The first end of the coupling unit is connected to the first voltage dividing end, the second end is connected to the second voltage dividing end, the third end is connected to the gate of the second transistor, and the fourth end is connected to the gate of the first transistor; The driving circuit is used for providing a second electrical signal different from the first electrical signal to the second power supply terminal.

2. The optical detector according to claim 1, characterized in that The first transistor is connected between the first power supply terminal and the photoelectric signal terminal; The driving circuit is used to provide a first electrical signal to the first power supply terminal, and obtain the first photoelectric signal through the photoelectric signal terminal.

3. The optical detector according to claim 1, characterized in that The voltage dividing unit includes a first resistor, a second resistor, a third transistor and a fourth transistor, the third transistor is a photosensitive transistor, and the fourth transistor is a transistor that is not illuminated by light; The first resistor is connected between the first power supply terminal and the second voltage dividing terminal; The third transistor is connected between the second voltage dividing terminal and the second power supply terminal, and the gate of the third transistor is connected to the first power supply terminal; The second resistor is connected between the first power supply terminal and the first voltage divider terminal; The fourth transistor is connected between the first voltage dividing terminal and the second power supply terminal, and a gate of the fourth transistor is connected to the first power supply terminal.

4. The optical detector according to claim 3, characterized in that The width-to-length ratio of the third transistor is the same as the width-to-length ratio of the first transistor.

5. The optical detector according to claim 1, characterized in that The coupling unit includes a fifth transistor and a sixth transistor; The fifth transistor is connected between the first voltage dividing terminal and the gate of the first transistor; The sixth transistor is connected between the second voltage dividing terminal and the gate of the second transistor; The gate of the fifth transistor and the gate of the sixth transistor are commonly connected to the first timing terminal; The driving circuit is used for providing a first timing signal to the first timing terminal.

6. The optical detector according to claim 5, characterized in that The coupling unit further includes a first capacitor and a second capacitor; The first capacitor is connected between the second timing terminal and the gate of the first transistor; The second capacitor is connected between the second timing terminal and the gate of the second transistor; The driving circuit is used for providing a second timing signal different from the first timing signal to the second timing terminal.

7. The optical detector according to claim 1, characterized in that The photosensitive circuit and the reference circuit both include transistors, and the transistors are both NMOS.

8. The optical detector according to claim 5, characterized in that The photodetector includes a first output stage; In the first output stage, the fifth transistor and the sixth transistor are turned on.

9. The optical detector according to claim 6, characterized in that The photodetector includes a second output stage; In the second output stage, the fifth transistor and the sixth transistor are turned off, and the gate voltage of the first transistor and the gate voltage of the second transistor are coupled to turn on the first transistor and the second transistor.

10. The optical detector according to claim 6, characterized in that The photodetector includes an off phase; In the turn-off phase, the gate voltage of the first transistor and the gate voltage of the second transistor are coupled to turn off the first transistor and the second transistor.

11. The optical detector according to claim 10, characterized in that In the turn-off phase, the fifth transistor and the sixth transistor are turned off; Alternatively, the turn-off phase includes a sub-discharging phase, during which the fifth transistor and the sixth transistor are turned on to discharge the gate of the first transistor and the gate of the second transistor.

12. The optical detector according to claim 11, characterized in that The start time of the discharge sub-stage is later than the start time of the shut-off stage; The end time of the discharge sub-phase is equal to or earlier than the end time of the shutdown phase.

13. The optical detector according to claim 1, characterized in that The first power supply terminal provides a high level signal, and the second power supply terminal provides a low level signal.

14. The optical detector according to claim 11, characterized in that The first power supply terminal provides a low level signal in the discharge sub-stage and provides a high level signal in other stages; The second power supply terminal provides a low level signal.

15. A display device, characterized in that: include: The light detector according to any one of claims 1 to 14, wherein the light detector is used to detect ambient light.

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