Backlight control circuit, control method thereof, and display device

Abstract

The present disclosure provides a backlight control circuit, a control method thereof, and a display device. In the backlight control circuit, a light flux sensing sub-circuit senses the light flux of the display device and outputs a obtained first control signal from a first control signal output terminal; the control sub-circuit includes N control units, and each control unit includes a first sub-unit and a second sub-unit; the first sub-unit is configured to conduct or disconnect the electrical connection between the output terminal of the second sub-unit and the backlight control signal output terminal under the control of the first control signal; the second sub-unit is configured to conduct or disconnect the electrical connection between the signal input terminal and the output terminal of the second sub-unit under the control of a second control signal output from a corresponding second control signal output terminal; the N second control signal output terminals provide valid second control signals in a time-division manner; the conduction thresholds corresponding to the N first sub-units increase in sequence, and when the first control signal and the conduction threshold of the first sub-unit conform to a corresponding relationship, the first sub-unit conducts.

Description

Technical Field

[0001] The present disclosure relates to the field of display technologies, and in particular, to a backlight control circuit, a control method thereof, and a display device. Background Art

[0002] With the continuous development of display technologies, the application scope of display products has become increasingly wide, and people's requirements for the user experience of display products have also become higher and higher. In order to better improve the user experience of display products, the light in the environment where the display products are applied is sensed, and then, according to the sensing result, the light output of the display products is adjusted so that users can have a more comfortable visual experience when viewing the pictures displayed by the display products. Summary of the Invention

[0003] The purpose of the present disclosure is to provide a backlight control circuit, a control method thereof, and a display device.

[0004] To achieve the above purpose, the present disclosure provides the following technical solutions:

[0005] In a first aspect of the present disclosure, a backlight control circuit is provided, which is applied to a display device. The backlight control circuit includes: a light flux sensing sub-circuit and a control sub-circuit;

[0006] The light flux sensing sub-circuit is configured to sense the light flux received by the display device in its environment, obtain a first control signal related to the light flux, and output the first control signal from a first control signal output end of the light flux sensing sub-circuit;

[0007] The control sub-circuit includes N control units, where N is a positive integer greater than or equal to 2. The control unit includes a first sub-unit and a second sub-unit; the first sub-unit is respectively coupled to the first control signal output end, an output end of the second sub-unit, and a backlight control signal output end; the first sub-unit is configured to conduct or disconnect an electrical connection between the output end of the second sub-unit and the backlight control signal output end under the control of the first control signal; the second sub-unit is further respectively coupled to a corresponding second control signal output end and a signal input end, and the second sub-unit is configured to conduct or disconnect an electrical connection between the signal input end and the output end of the second sub-unit under the control of a second control signal output from the corresponding second control signal output end;

[0008] The N second control signal output ends corresponding to the N second sub-units provide valid second control signals in a time-sharing manner; the conduction thresholds corresponding to the N first sub-units increase in sequence. When the first control signal and the conduction threshold of the first sub-unit conform to a corresponding relationship, the first sub-unit conducts the electrical connection between the output end of the second sub-unit and the backlight control signal output end.

[0009] Optionally, the first sub-unit includes a first transistor, the gate of the first transistor is coupled to the first control signal output terminal, the first pole of the first transistor is coupled to the output terminal of the second sub-unit, and the second pole of the first transistor is coupled to the backlight control signal output terminal.

[0010] Optionally, the second sub-unit includes a second transistor, the gate of the second transistor is coupled to the corresponding second control signal output terminal, the first pole of the second transistor is coupled to the signal input terminal, and the second pole of the second transistor serves as the output terminal of the second sub-unit.

[0011] Optionally, the light flux sensing sub-circuit includes: a first photosensitive transistor, a second photosensitive transistor, a subtractor, and a light-shielding pattern;

[0012] The light-shielding pattern shields the second photosensitive transistor;

[0013] The gates of the first photosensitive transistor and the second photosensitive transistor are both coupled to the first signal terminal, the first poles of the first photosensitive transistor and the second photosensitive transistor are both coupled to the second signal terminal, the second pole of the first photosensitive transistor is coupled to the first input terminal of the subtractor, the second pole of the second photosensitive transistor is coupled to the second input terminal of the subtractor, and the output terminal of the subtractor is coupled to the first control signal output terminal.

[0014] Optionally, the subtractor includes: a first operational amplifier, a first resistor unit, and a second resistor unit;

[0015] The first input terminal of the first operational amplifier is coupled to the second pole of the first photosensitive transistor, the second input terminal of the first operational amplifier is coupled to the second pole of the second photosensitive transistor, and the output terminal of the first operational amplifier is coupled to the first control signal output terminal;

[0016] The first end of the first resistor unit is coupled to the first input terminal of the first operational amplifier, and the second end of the first resistor unit is connected to the ground signal;

[0017] The first end of the second resistor unit is coupled to the second input terminal of the first operational amplifier, and the second end of the second resistor unit is connected to the ground signal.

[0018] Optionally, the light flux sensing sub-circuit further includes an integrator; the first input terminal of the integrator is coupled to the output terminal of the subtractor, the second end of the integrator is connected to the ground signal, and the output terminal of the integrator is coupled to the first control signal output terminal.

[0019] Optionally, the integrator includes: a second operational amplifier, a third resistor unit, a fourth resistor unit, and a capacitor unit;

[0020] A first end of the third resistor unit is coupled to an output end of the subtractor, and a second end of the third resistor unit is coupled to a first input end of the second operational amplifier;

[0021] A first end of the fourth resistor unit is connected to a ground signal, and a second end of the fourth resistor unit is coupled to a second input end of the second operational amplifier;

[0022] A first end of the capacitor unit is coupled to the first input end of the second operational amplifier, and a second end of the capacitor unit is coupled to an output end of the second operational amplifier;

[0023] An output end of the second operational amplifier is coupled to the first control signal output end.

[0024] Optionally, the luminous flux sensing sub-circuit further includes:

[0025] A control reset unit, the control reset unit is respectively coupled to a third signal terminal, a first end of the capacitor unit, and a second end of the capacitor unit, and the control reset unit is configured to control conduction or disconnection of an electrical connection between the first end of the capacitor unit and the second end of the capacitor unit under the control of a signal input at the third signal terminal.

[0026] Optionally, the luminous flux sensing sub-circuit further includes:

[0027] An inverting operational amplifier, an in-phase input end of the inverting operational amplifier is connected to a ground signal, an inverting input end of the inverting operational amplifier is coupled to an output end of the integrator, and an output end of the inverting operational amplifier is coupled to the first control signal output end.

[0028] Based on the technical solution of the above backlight control circuit, a second aspect of the present disclosure provides a control method for a backlight control circuit, which is applied to the above backlight control circuit. The backlight control circuit includes: a luminous flux sensing sub-circuit and a control sub-circuit; the control method includes:

[0029] During the acquisition stage, the luminous flux sensing subcircuit senses the luminous flux received by the display device in its environment, obtains a first control signal related to the luminous flux, and outputs the first control signal from the first control signal output terminal of the luminous flux sensing subcircuit; the N second control signal output terminals corresponding to the N second subunits provide effective second control signals in a time-sharing manner, and the effective second control signals control the electrical connection between the corresponding second subunit conduction signal input terminal and the output terminal of the second subunit; when there is a corresponding relationship between the first control signal and the conduction threshold of the first subunit, the first subunit conducts the electrical connection between the output terminal of the second subunit and the backlight control signal output terminal.

[0030] Optionally, the first subunit includes a first transistor, and the second subunit includes a second transistor, wherein the gate of the first transistor is coupled to the first control signal output terminal, the first electrode of the first transistor is coupled to the second electrode of the second transistor, and the second electrode of the first transistor is coupled to the backlight control signal output terminal; the gate of the second transistor is coupled to the corresponding second control signal output terminal, and the first electrode of the second transistor is coupled to the signal input terminal;

[0031] In the acquisition phase, the effective second control signal controls the corresponding second transistor to be turned on; when there is a corresponding relationship between the first control signal and the turn-on threshold of the first transistor, the first transistor is turned on.

[0032] Based on the technical solution of the above-mentioned backlight control circuit, the third aspect of the present disclosure provides a display device, including the above-mentioned backlight control circuit, and the display device also includes: a backlight driving circuit and a backlight source coupled to each other; the backlight driving circuit is also coupled to the backlight control signal output end, and the backlight driving circuit is used to output a corresponding backlight driving signal to the backlight source under the control of the backlight control signal output from the backlight control signal output end. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] The drawings described herein are used to provide a further understanding of the present disclosure and constitute a part of the present disclosure. The exemplary embodiments of the present disclosure and their descriptions are used to explain the present disclosure and do not constitute an improper limitation of the present disclosure. In the drawings:

[0034] Figure 1 A schematic diagram of a backlight control circuit controlling a backlight source according to an embodiment of the present disclosure;

[0035] Figure 2 A circuit structure diagram of a backlight control circuit provided in an embodiment of the present disclosure;

[0036] Figure 3 A timing diagram of the operation of the backlight control circuit provided in an embodiment of the present disclosure;

[0037] Figure 4 Schematic diagram of the relationship between luminous flux and backlight brightness provided by embodiments of the present disclosure. Detailed implementation manners

[0038] In order to further illustrate the backlight control circuit, its control method, and the display device provided by embodiments of the present disclosure, the following will be described in detail with reference to the accompanying drawings of the specification.

[0039] In the related art, when a display product changes the backlight emission power by sensing the magnitude of the ambient light flux to adjust the brightness of the module, the general architecture is as follows: An ALS (English: Ambient Light Sensor; Chinese: Ambient Light Sensor) three-in-one light sensor chip is used to transmit the light flux information to the main board platform, and a backlight control signal is sent to the backlight driving circuit (such as: LED Driver) through the main board platform, thereby changing the backlight emission brightness.

[0040] The following problems exist in adopting the above architecture:

[0041] It is necessary to use digital circuit devices on the main board platform for digital circuit logic operations to convert the light sensor signal into an LED PWM signal for controlling the backlight, which not only has high cost but also high power consumption.

[0042] Please refer to Figures 1 to 3 , embodiments of the present disclosure provide a backlight control circuit 10, which is applied to a display device. The backlight control circuit 10 includes: a light flux sensing sub-circuit 101 and a control sub-circuit 102;

[0043] The light flux sensing sub-circuit 101 is configured to sense the light flux received by the display device in its environment, obtain a first control signal related to the light flux, and output the first control signal from the first control signal output terminal Vk of the light flux sensing sub-circuit 101.

[0044] The control sub-circuit 102 includes N control units 1021, where N is a positive integer greater than or equal to 2. The control unit 1021 includes a first sub-unit (such as a first transistor T1) and a second sub-unit (such as a second transistor T2); the first sub-unit is respectively coupled to the first control signal output terminal Vk, the output terminal of the second sub-unit, and the backlight control signal output terminal PWM; the first sub-unit is configured to conduct or disconnect the electrical connection between the output terminal of the second sub-unit and the backlight control signal output terminal PWM under the control of the first control signal; the second sub-unit is also respectively coupled to the corresponding second control signal output terminal and the signal input terminal, and the second sub-unit is configured to conduct or disconnect the electrical connection between the signal input terminal (input signal Source_1) and the output terminal of the second sub-unit under the control of the second control signal (such as Gate_1 to Gate_N) output from the corresponding second control signal output terminal;

[0045] The N second control signal output terminals corresponding to the N second sub-units provide valid second control signals in a time-division manner; the conduction thresholds corresponding to the N first sub-units increase in sequence. When the first control signal and the conduction threshold of the first sub-unit conform to a corresponding relationship, the first sub-unit conducts the electrical connection between the output terminal of the second sub-unit and the backlight control signal output terminal PWM.

[0046] Exemplarily, the display device includes a display panel and a main board connected to the display panel, and the main board includes a flexible circuit board or a printed circuit board. The light flux sensing sub-circuit 101 is disposed on the main board and is configured to sense the light flux received by the display panel in its environment.

[0047] Exemplarily, the first control signal is positively correlated with the light flux received by the display device in its environment.

[0048] Exemplarily, among the N control units 1021, the first sub-units included in each control unit 1021 are all coupled to the first control signal output terminal Vk and are controlled by the first control signal. When the first control signal and the conduction threshold of the first sub-unit conform to a corresponding relationship, the first sub-unit conducts the electrical connection between the output terminal of the second sub-unit and the backlight control signal output terminal PWM.

[0049] Exemplarily, the N second control signal output terminals corresponding to the N second sub-units provide valid second control signals in a time-division manner, and can control the N second sub-units to conduct the electrical connection between the signal input terminal and the output terminal of the second sub-unit in a time-division manner.

[0050] Exemplarily, when there is a corresponding relationship between the first control signal and the conduction threshold of the first subunit, the first subunit conducts the electrical connection between the output terminal of the second subunit and the backlight control signal output terminal PWM. When there is no corresponding relationship between the first control signal and the conduction threshold of the first subunit, the first subunit disconnects the electrical connection between the output terminal of the second subunit and the backlight control signal output terminal PWM.

[0051] Exemplarily, when the first subunit conducts the electrical connection between the output terminal of the second subunit and the backlight control signal output terminal PWM, when the second subunit belonging to the same control unit 1021 as the first subunit conducts, it can enable the signal input terminal to be electrically connected to the backlight control signal output terminal PWM through the second subunit and the first subunit, so that the backlight control signal output terminal PWM outputs a valid level signal, and the duty cycle of the backlight control signal output by the backlight control signal output terminal PWM is increased.

[0052] According to the specific structure of the above-mentioned backlight control circuit 10, in the backlight control circuit 10 provided by the embodiments of the present disclosure, the luminous flux sensing sub-circuit 101 is provided. The luminous flux sensing sub-circuit 101 can sense the luminous flux received by the display device in its surrounding environment, and can output a first control signal related to the luminous flux from the first control signal output terminal Vk of the luminous flux sensing sub-circuit 101.

[0053] In the backlight control circuit 10 provided by the embodiments of the present disclosure, N control units 1021 are provided, and each control unit 1021 includes a first subunit and a second subunit; the N second control signal output terminals corresponding to the N second subunits included in the N control units 1021 provide valid second control signals in a time-sharing manner. When the second subunit provides a valid second control signal at the second control signal output terminal to which it is coupled, the electrical connection between the signal input terminal and the output terminal of the second subunit is conducted; the conduction thresholds corresponding to the N first subunits included in the N control units 1021 increase in sequence. When there is a corresponding relationship between the first control signal and the conduction threshold of the first subunit, the first subunit conducts the electrical connection between the output terminal of the second subunit and the backlight control signal output terminal PWM.

[0054] In the backlight control circuit 10 provided by the embodiments of the present disclosure, the first control signal is related to the luminous flux. When the first control signal conforms to the corresponding relationship with the conduction thresholds of more first sub-units, more first sub-units will conduct. When the first control signal conforms to the corresponding relationship with the conduction thresholds of fewer first sub-units, fewer first sub-units will conduct. Therefore, when the display panel receives different luminous fluxes, the number of first sub-units controlled to conduct is different. At the same time, by setting N second sub-units to conduct in a time-sharing manner, it is realized that the control unit 1021 corresponding to the conducted first sub-units can control the electrical connection between the signal input end and the backlight control signal output end PWM in a time-sharing manner, thereby changing the duty cycle of the backlight control signal output by the backlight control signal output end PWM. The higher the duty cycle of the backlight control signal, the greater the power output by the backlight source 30, and the higher the brightness of the display panel.

[0055] It should be noted that when the first sub-unit conducts, that is, under the control of the first control signal, the first sub-unit conducts the electrical connection between the output end of the second sub-unit and the backlight control signal output end PWM. When the second sub-unit conducts, that is, under the control of the corresponding second control signal, the second sub-unit conducts the electrical connection between the signal input end and the output end of the second sub-unit.

[0056] Therefore, in the backlight control circuit 10 provided by the embodiments of the present disclosure, by setting the backlight control circuit 10 to include a luminous flux sensing sub-circuit 101 and a control sub-circuit 102, a corresponding relationship between the luminous flux and the backlight control signal is established, and the backlight can be directly controlled according to the luminous flux. Without relying on the digital circuit devices of the main board for digital circuit logic operations, the light sensing signal can be converted into a backlight control signal for controlling the backlight, which not only effectively reduces the cost but also reduces the power consumption of the main board.

[0057] Such as Figure 2 and Figure 3 As shown, in some embodiments, the first sub-unit includes a first transistor T1. The gate of the first transistor T1 is coupled to the first control signal output end Vk. The first pole of the first transistor T1 is coupled to the output end of the second sub-unit. The second pole of the first transistor T1 is coupled to the backlight control signal output end PWM.

[0058] Exemplarily, the conduction thresholds (such as: threshold voltages) of the N first transistors T1 included in the N first sub-units increase in sequence. In the acquisition stage P1, when the first control signal conforms to the corresponding relationship with the conduction threshold of the first transistor T1, the first transistor T1 conducts.

[0059] In some embodiments, the second sub-unit includes a second transistor T2. The gate of the second transistor T2 is coupled to a corresponding second control signal output terminal. The first pole of the second transistor T2 is coupled to the signal input terminal. The second pole of the second transistor T2 serves as the output terminal of the second sub-unit.

[0060] Exemplarily, an effective second control signal controls the corresponding second transistor T2 to turn on. When the second transistor T2 includes an NMOS transistor, the effective second control signal is that the second control signal is at a high level. When the second transistor T2 includes a PMOS transistor, the effective second control signal is that the second control signal is at a low level.

[0061] As Figure 2 and Figure 3 shown, more specifically, take the example where both the first transistor T1 and the second transistor T2 include NMOS transistors. The first control signal is connected to the gates of the first transistors T1 with different threshold voltages. The gates of the N second transistors T2 are correspondingly connected to the second control signals Gate_1, Gate_2, Gate_3 to Gate_N. When the timing of the signals Source_1 input at the signal input terminal and Gate_1, Gate_2, Gate_3 to Gate_N is as Figure 3 shown, each second transistor T2 is turned on in sequence, and the signal Source_1 is transmitted to each first transistor T1. The threshold voltages of the N first transistors T1 gradually increase. When the first control signal is at a fixed potential, only the first transistors T1 with a threshold voltage less than this fixed potential will turn on, and the other first transistors T1 are all turned off. Figure 3 schematically shows that only two first transistors T1 are turned on.

[0062] It should be noted that as the potential of the first control signal increases, the number of first transistors T1 that can be turned on increases. Therefore, the duty cycle of the backlight control signal is positively correlated with the first control signal, that is, the high-potential duty cycle of the backlight control signal is positively correlated with the light flux received by the display panel. The higher the high-potential duty cycle of the backlight control signal, the greater the power output by the backlight source 30, and the higher the brightness of the display panel.

[0063] As Figure 2 shown, in some embodiments, the light flux sensing sub-circuit 101 includes: a first photosensitive transistor T3, a second photosensitive transistor T4, a subtractor 1011, and a light-shielding pattern;

[0064] The light-shielding pattern shields the second photosensitive transistor T4;

[0065] The gates of the first photosensitive transistor T3 and the second photosensitive transistor T4 are both coupled to the first signal terminal V1. The first electrodes of the first photosensitive transistor T3 and the second photosensitive transistor T4 are both coupled to the second signal terminal V2. The second electrode of the first photosensitive transistor T3 is coupled to the first input terminal of the subtractor 1011. The second electrode of the second photosensitive transistor T4 is coupled to the second input terminal of the subtractor 1011. The output terminal OUT1 of the subtractor 1011 is coupled to the first control signal output terminal Vk.

[0066] Exemplarily, the first photosensitive transistor T3 and the second photosensitive transistor T4 have the same characteristics.

[0067] Exemplarily, the subtractor 1011 is configured to subtract the signals input to its first input terminal and second input terminal and then output the result.

[0068] As Figure 2 shown, the first signal terminal V1 inputs a first signal, and the second signal terminal V2 inputs a second signal. When the display panel is in a 0 lux dark environment, the first photosensitive transistor T3 and the second photosensitive transistor T4 have the same electrical characteristics, and the output electrical signals are consistent. In this case, the output potential of the output terminal of the subtractor 1011 is 0. When the display panel is in an illuminated environment with a certain brightness, the electrical characteristics of the first photosensitive transistor T3 change, and the potential of the electrical signal output by the first photosensitive transistor T3 is higher than the potential of the electrical signal output by the second photosensitive transistor T4. The output terminal of the subtractor 1011 outputs a signal after subtraction operation, and this signal is positively correlated with the light flux.

[0069] The above-described light flux sensing sub-circuit 101 includes: a first photosensitive transistor T3, a second photosensitive transistor T4, a subtractor 1011, and a light-shielding pattern, such that the output terminal of the subtractor 1011 can output a signal that is positively correlated with the light flux, and the signal output by the output terminal of the subtractor 1011 can be directly used as the first control signal.

[0070] As Figure 2 and Figure 3 shown, in some embodiments, the subtractor 1011 includes: a first operational amplifier OP1, a first resistor unit R1, and a second resistor unit R2;

[0071] The first input terminal of the first operational amplifier OP1 is coupled to the second electrode of the first photosensitive transistor T3. The second input terminal of the first operational amplifier OP1 is coupled to the second electrode of the second photosensitive transistor T4. The output terminal of the first operational amplifier OP1 is coupled to the first control signal output terminal Vk.

[0072] The first end of the first resistor unit R1 is coupled to the first input terminal of the first operational amplifier OP1, and the second end of the first resistor unit R1 is connected to the ground signal;

[0073] The first end of the second resistor unit R2 is coupled to the second input terminal of the first operational amplifier OP1, and the second end of the second resistor unit R2 is connected to the ground signal.

[0074] Exemplarily, the first input terminal of the first operational amplifier OP1 includes a non-inverting input terminal, and the second input terminal of the first operational amplifier OP1 includes an inverting input terminal.

[0075] Exemplarily, the resistance values of the first resistor unit R1 and the second electronic unit are equal.

[0076] Such as Figure 2 and Figure 3 As shown, in some embodiments, the light flux sensing sub-circuit 101 further includes an integrator 1012; the first input terminal of the integrator 1012 is coupled to the output terminal of the subtractor 1011, the second end of the integrator 1012 is connected to the ground signal, and the output terminal OUT2 of the integrator 1012 is coupled to the first control signal output terminal Vk.

[0077] Exemplarily, the first input terminal of the integrator 1012 serves as a non-inverting input terminal, and the second input terminal of the integrator 1012 serves as an inverting input terminal.

[0078] Exemplarily, the signal output by the output terminal of the integrator 1012 can directly serve as the first control signal.

[0079] The above setting that the light flux sensing sub-circuit 101 further includes an integrator 1012 enables the integrator 1012 to accumulate the charge of the electrical signal output by the subtractor 1011, and the signal finally output by the integrator 1012 can serve as the first control signal, which is beneficial to improving the sensing accuracy.

[0080] Such as Figure 2 and Figure 3 As shown, in some embodiments, the integrator 1012 includes: a second operational amplifier OP2, a third resistor unit R3, a fourth resistor unit R4, and a capacitor unit C;

[0081] The first end of the third resistor unit R3 is coupled to the output terminal of the subtractor 1011, and the second end of the third resistor unit R3 is coupled to the first input terminal of the second operational amplifier OP2;

[0082] The first end of the fourth resistor unit R4 is connected to the ground signal, and the second end of the fourth resistor unit R4 is coupled to the second input terminal of the second operational amplifier OP2;

[0083] The first end of the capacitor unit C is coupled to the first input terminal of the second operational amplifier OP2, and the second end of the capacitor unit C is coupled to the output terminal of the second operational amplifier OP2;

[0084] The output terminal of the second operational amplifier OP2 is coupled to the first control signal output terminal Vk.

[0085] Exemplarily, the resistance values of the third resistor unit R3 and the fourth resistor unit R4 are equal.

[0086] Exemplarily, the current flowing through the third resistor unit R3 is equal to the current charging the capacitor unit C. Based on the virtual short principle of the operational amplifier, the potential at the second end of the third resistor unit R3 is equal to GND (i.e., the ground signal). Define the potential of the signal output by the first operational amplifier OP1 as Vout1, and the potential of the signal output by the second operational amplifier OP2 as Vout2. The current I1 passing through the third resistor unit R3 = Vout1 / R3, where R3 represents the resistance value of the third resistor unit R3 in the formula; according to the capacitance definition C = Q / U and the current definition I = dQ / dt, the current I2 charging the capacitor unit C = C×d(0 - Vout2) / dt; in the formula, C represents the capacitance value of the capacitor unit C, Q represents the accumulated charge amount of the capacitor unit C, and U represents the voltage applied across the two plates of the capacitor unit C.

[0087] According to I1 = I2, the solution is obtained as:

[0088] Vout2 = -∫(Vout1)dt / (C×R3),

[0089] As Figure 3 shown, when the subtractor 1011 stops outputting the high potential, the integrator 1012 stops charging the capacitor unit C, and the potential at the output terminal of the second operational amplifier OP2 remains stable until the reset stage P2.

[0090] As Figure 2 and Figure 3 shown, in some embodiments, the luminous flux sensing sub - circuit 101 further includes:

[0091] A control reset unit 1013, the control reset unit 1013 is respectively coupled to the third signal terminal V3, the first end of the capacitor unit C and the second end of the capacitor unit C. The control reset unit 1013 is configured to control the electrical connection between the first end of the capacitor unit C and the second end of the capacitor unit C to be turned on or off under the control of the signal input at the third signal terminal V3.

[0092] Exemplarily, the control reset unit 1013 includes a control transistor T5. The gate of the control transistor T5 is coupled to the third signal line. The first pole of the control transistor T5 is coupled to the first end of the capacitor unit C. The second end of the control transistor T5 is coupled to the second end of the capacitor unit C. The control transistor T5 is turned on or off under the control of the third signal input at the third signal line.

[0093] Exemplarily, the control transistor T5 includes an NMOS transistor.

[0094] Exemplarily, in the acquisition stage P1, the control reset unit 1013 controls to disconnect the electrical connection between the first end of the capacitor unit C and the second end of the capacitor unit C under the control of the signal input at the third signal terminal V3. In the reset stage P2, the control reset unit 1013 controls to connect the electrical connection between the first end of the capacitor unit C and the second end of the capacitor unit C under the control of the signal input at the third signal terminal V3.

[0095] The above-mentioned light flux sensing sub-circuit 101 further includes a control reset unit 1013, so that the control reset unit can discharge and reset the capacitor unit C in the reset stage P2 and wait for the start of the next frame of sampling.

[0096] As Figure 2 and Figure 3 shown, in some embodiments, the light flux sensing sub-circuit 101 further includes:

[0097] An inverting operational amplifier OP3. The non-inverting input terminal of the inverting operational amplifier OP3 is connected to the ground signal. The inverting input terminal of the inverting operational amplifier OP3 is coupled to the output terminal of the integrator 1012. The output terminal OUT3 of the inverting operational amplifier OP3 is coupled to the first control signal output terminal Vk.

[0098] The potential signal at the output terminal of the inverting operational amplifier OP3 is:

[0099] Vout3 = ∫(Vout1)dt / (C×R3)

[0100] The above-described light flux sensing sub-circuit 101 further includes an inverting operational amplifier OP3, which can control the potential of the first control signal to be positive.

[0101] As Figure 4 shown, exemplarily, the light flux is positively correlated with the signal output by the subtractor 1011, the signal output by the subtractor 1011 is negatively correlated with the signal output by the integrator 1012, the signal output by the integrator 1012 is opposite to the signal output by the inverting operational amplifier OP3, the signal output by the inverting operational amplifier OP3 is positively correlated with the number of turned-on first transistors T1, the number of turned-on first transistors T1 is positively correlated with the duty cycle of the backlight control signal, and the duty cycle of the backlight control signal is positively correlated with the backlight brightness.

[0102] Exemplarily, N is equal to 1000, the adjustment range of the backlight brightness is between 100 nit and 10000 nit, the signal potential range of the output of the inverting operational amplifier OP3 is between 200 mV and 1.2 V, and the threshold voltage range of the first transistor T1 is between 200 mV and 1200 mV; the threshold voltages of N first transistors T1 gradually increase, and the threshold voltage difference between adjacent first transistors T1 is 1 mV. The brightness increased by the turn-on of the first first transistor T1 is 100 nit, and for each additional turned-on first transistor T1, the corresponding increase in brightness is 9.9 nit. Exemplarily, the voltage value corresponding to the first control signal is 500 mV, the number of turned-on first transistors T1 is 301, and the output brightness of the backlight source 30 is controlled to be 2970 nit.

[0103] In the backlight control circuit 10 provided in the above embodiment, when the light flux of the display panel changes, the electrical signal difference between the first photosensitive transistor T3 and the second photosensitive transistor T4 changes in a positive correlation, thereby causing the signals output by each operational amplifier to change. By setting triodes with different turn-on voltages, a positive correlation is formed between the potential of the first control signal and the number of triodes that can be turned on, so that through a specific timing, the higher the signal potential, the larger the duty cycle of the high potential of the backlight control signal output within one cycle, thereby realizing a direct monotonic mapping from the light flux to the backlight control signal without digital circuit logic operations.

[0104] The embodiments of the present disclosure also provide a control method for a backlight control circuit 10, which is applied to the backlight control circuit 10 provided in the above embodiment. The backlight control circuit 10 includes: a light flux sensing sub-circuit 101 and a control sub-circuit 102; the control method includes:

[0105] In the acquisition stage P1, the light flux sensing sub-circuit 101 senses the light flux received by the display device in its environment, obtains a first control signal related to the light flux, and outputs the first control signal from the first control signal output terminal Vk of the light flux sensing sub-circuit 101; the N second control signal output terminals corresponding to the N second sub-units provide valid second control signals in a time-sharing manner, and the valid second control signals control the electrical connection between the conduction signal input terminal of the corresponding second sub-unit and the output terminal of the second sub-unit; when the first control signal and the conduction threshold of the first sub-unit conform to a corresponding relationship, the first sub-unit conducts the electrical connection between the output terminal of the second sub-unit and the backlight control signal output terminal PWM.

[0106] Exemplarily, one cycle includes an acquisition stage P1 and a reset stage P2.

[0107] In the backlight control circuit 10 provided in the above embodiment, N control units 1021 are provided, and each control unit 1021 includes a first sub-unit and a second sub-unit; the N second control signal output terminals corresponding to the N second sub-units included in the N control units 1021 provide valid second control signals in a time-sharing manner, and when the second control signal output terminal to which the second sub-unit is coupled provides a valid second control signal, the second sub-unit conducts the electrical connection between the signal input terminal and the output terminal of the second sub-unit; the conduction thresholds corresponding to the N first sub-units included in the N control units 1021 increase in sequence, and when the first control signal and the conduction threshold of the first sub-unit conform to a corresponding relationship, the first sub-unit conducts the electrical connection between the output terminal of the second sub-unit and the backlight control signal output terminal PWM.

[0108] In the backlight control circuit 10 provided in the above embodiment, the first control signal is related to the light flux, and when the first control signal conforms to a corresponding relationship with the conduction thresholds of more first sub-units, more first sub-units will conduct, and when the first control signal conforms to a corresponding relationship with the conduction thresholds of fewer first sub-units, fewer first sub-units will conduct. Therefore, when the light flux received by the display panel is different, the number of first sub-units controlled to conduct is different. At the same time, by setting the N second sub-units to conduct in a time-sharing manner, it is realized that the control units 1021 corresponding to the conducted first sub-units can control the conduction of the electrical connection between the signal input terminal and the backlight control signal output terminal PWM in a time-sharing manner, thereby changing the duty cycle of the backlight control signal output by the backlight control signal output terminal PWM. And the higher the duty cycle of the backlight control signal, the greater the power output by the backlight source 30, and the higher the brightness of the display panel.

[0109] Therefore, when the backlight control circuit 10 is controlled by using the control method provided by the embodiments of the present disclosure, the corresponding relationship between the luminous flux and the backlight control signal is established, and the backlight can be directly controlled according to the luminous flux. Without relying on the digital circuit devices on the main board for digital circuit logic operations, the light sensing signal can be converted into a backlight control signal for controlling the backlight, which not only effectively reduces the cost but also reduces the power consumption of the main board.

[0110] In some embodiments, the first sub-unit includes a first transistor T1, the second sub-unit includes a second transistor T2, the gate of the first transistor T1 is coupled to the first control signal output terminal Vk, the first pole of the first transistor T1 is coupled to the second pole of the second transistor T2, and the second pole of the first transistor T1 is coupled to the backlight control signal output terminal PWM; the gate of the second transistor T2 is coupled to the corresponding second control signal output terminal, and the first pole of the second transistor T2 is coupled to the signal input terminal;

[0111] In the acquisition stage P1, the effective second control signal controls the corresponding second transistor T2 to conduct; when the first control signal and the conduction threshold of the first transistor T1 conform to the corresponding relationship, the first transistor T1 conducts.

[0112] In the reset stage P2, the second control signal controls the corresponding second transistor T2 to cut off; the first control signal and the conduction threshold of the first transistor T1 do not conform to the corresponding relationship, and the first transistor T1 cuts off.

[0113] As Figure 1 and Figure 2 shown, the embodiments of the present disclosure further provide a display device, including the backlight control circuit 10 provided by the above embodiments. The display device further includes: a backlight driving circuit 20 and a backlight source 30 that are coupled to each other; the backlight driving circuit 20 is further coupled to the backlight control signal output terminal PWM, and the backlight driving circuit 20 is configured to output a corresponding backlight driving signal to the backlight source 30 under the control of the backlight control signal output from the backlight control signal output terminal PWM.

[0114] Exemplarily, the display device further includes a display panel. The backlight control circuit 10 is disposed on a flexible circuit board or a printed circuit board, and the flexible circuit board or the printed circuit board is connected to the display panel.

[0115] Exemplarily, the backlight control circuit 10 outputs a backlight control signal to the backlight driving circuit 20. The backlight driving circuit 20 is configured to output a corresponding backlight driving signal to the backlight source 30 under the control of the backlight control signal. The backlight source 30 realizes a corresponding backlight brightness according to the backlight driving signal.

[0116] It should be noted that the display device may be: a television, a monitor, a digital photo frame, a mobile phone, a tablet computer, or any other product or component with a display function. Among them, the display device further includes a flexible circuit board, a printed circuit board, a backplane, and the like.

[0117] The display device provided by the embodiments of the present disclosure directly outputs a backlight control signal by using a backlight control circuit integrated on the display panel, saving the ALS photosensitive chip and digital circuit devices for logical calculation. This not only saves the power consumption and cost brought by these devices, but also can meet the user's functional requirements for changing the module brightness according to the ambient light flux.

[0118] In the method embodiments of the present disclosure, the sequence numbers of the steps do not limit the order of the steps. For those of ordinary skill in the art, without creative efforts, the changes in the order of the steps are also within the protection scope of the present disclosure.

[0119] It should be noted that the embodiments in this specification are all described in a progressive manner. The same or similar parts among the embodiments can be referred to each other. Each embodiment focuses on the differences from other embodiments. In particular, for the method embodiments, since they are basically similar to the product embodiments, the description is relatively simple, and the relevant parts can refer to the partial description of the product embodiments.

[0120] Unless otherwise defined, the technical terms or scientific terms used in the present disclosure should have the ordinary meaning understood by those of ordinary skill in the art in the field to which the present disclosure belongs. The "first", "second" and similar terms used in the present disclosure do not indicate any order, quantity or importance, but are only used to distinguish different components. The terms such as "including" or "comprising" mean that the elements or objects appearing before the term cover the elements or objects listed after the term and their equivalents, without excluding other elements or objects. The terms such as "connected", "coupled" or "linked" are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. The terms such as "up", "down", "left", "right" are only used to represent relative position relationships. When the absolute position of the object to be described changes, the relative position relationship may also change accordingly.

[0121] It will be understood that when an element such as a layer, film, region, or substrate is referred to as being “on” or “under” another element, it can be directly “on” or “under” the other element, or intervening elements may be present.

[0122] In the description of the above embodiments, specific features, structures, materials, or characteristics may be combined in any one or more embodiments or examples in a suitable manner.

[0123] As described above, the specific embodiments of the present disclosure are merely provided, but the protection scope of the present disclosure is not limited thereto. Any person skilled in the art can easily conceive of changes or substitutions within the technical scope disclosed by the present disclosure, and all such changes or substitutions should be covered by the protection scope of the present disclosure. Therefore, the protection scope of the present disclosure should be subject to the protection scope of the claims.

Claims

1. A backlight control circuit, applied to a display device, the backlight control circuit comprising: Light flux sensing sub - circuit and control sub - circuit; The light flux sensing sub - circuit is used to sense the light flux received by the display device in its environment, obtain a first control signal related to the light flux, and output the first control signal from the first control signal output end of the light flux sensing sub - circuit; The control sub - circuit includes N control units, where N is a positive integer greater than or equal to 2. The control unit includes a first sub - unit and a second sub - unit; The first sub - unit is respectively coupled to the first control signal output end, the output end of the second sub - unit, and the backlight control signal output end; The first sub - unit is used to conduct or disconnect the electrical connection between the output end of the second sub - unit and the backlight control signal output end under the control of the first control signal; The second sub - unit is also respectively coupled to the corresponding second control signal output end and the signal input end, and the second sub - unit is used to conduct or disconnect the electrical connection between the signal input end and the output end of the second sub - unit under the control of the second control signal output from the corresponding second control signal output end; The N second control signal output ends corresponding to the N second sub - units provide valid second control signals in a time - sharing manner; The conduction thresholds of the N first sub - units increase in sequence. When the first control signal and the conduction threshold of the first sub - unit conform to the corresponding relationship, the first sub - unit conducts the electrical connection between the output end of the second sub - unit and the backlight control signal output end.

2. The backlight control circuit according to claim 1, wherein, The first sub - unit includes a first transistor. The gate of the first transistor is coupled to the first control signal output end, the first pole of the first transistor is coupled to the output end of the second sub - unit, and the second pole of the first transistor is coupled to the backlight control signal output end.

3. The backlight control circuit according to claim 1, wherein, The second sub - unit includes a second transistor. The gate of the second transistor is coupled to the corresponding second control signal output end, the first pole of the second transistor is coupled to the signal input end, and the second pole of the second transistor serves as the output end of the second sub - unit.

4. The backlight control circuit according to claim 1, wherein, The light flux sensing sub - circuit includes: a first photosensitive transistor, a second photosensitive transistor, a subtractor, and a light - shielding pattern; The light - shielding pattern shields the second photosensitive transistor; The gates of the first photosensitive transistor and the second photosensitive transistor are both coupled to the first signal end, the first poles of the first photosensitive transistor and the second photosensitive transistor are both coupled to the second signal end, the second pole of the first photosensitive transistor is coupled to the first input end of the subtractor, the second pole of the second photosensitive transistor is coupled to the second input end of the subtractor, and the output end of the subtractor is coupled to the first control signal output end.

5. The backlight control circuit according to claim 4, wherein, The subtractor includes: a first operational amplifier, a first resistor unit, and a second resistor unit; The first input terminal of the first operational amplifier is coupled to the second pole of the first photosensitive transistor, the second input terminal of the first operational amplifier is coupled to the second pole of the second photosensitive transistor, and the output terminal of the first operational amplifier is coupled to the first control signal output terminal; The first end of the first resistor unit is coupled to the first input terminal of the first operational amplifier, and the second end of the first resistor unit is connected to a ground signal; The first end of the second resistor unit is coupled to the second input terminal of the first operational amplifier, and the second end of the second resistor unit is connected to a ground signal.

6. The backlight control circuit according to claim 4, wherein, The luminous flux sensing sub-circuit further includes an integrator; the first input terminal of the integrator is coupled to the output terminal of the subtractor, the second end of the integrator is connected to a ground signal, and the output terminal of the integrator is coupled to the first control signal output terminal.

7. The backlight control circuit according to claim 6, wherein, The integrator includes: a second operational amplifier, a third resistor unit, a fourth resistor unit, and a capacitor unit; The first end of the third resistor unit is coupled to the output terminal of the subtractor, and the second end of the third resistor unit is coupled to the first input terminal of the second operational amplifier; The first end of the fourth resistor unit is connected to a ground signal, and the second end of the fourth resistor unit is coupled to the second input terminal of the second operational amplifier; The first end of the capacitor unit is coupled to the first input terminal of the second operational amplifier, and the second end of the capacitor unit is coupled to the output terminal of the second operational amplifier; The output terminal of the second operational amplifier is coupled to the first control signal output terminal.

8. The backlight control circuit according to claim 7, wherein, The luminous flux sensing sub-circuit further includes: A control reset unit, which is respectively coupled to the third signal terminal, the first end of the capacitor unit, and the second end of the capacitor unit. The control reset unit is used to control the conduction or disconnection of the electrical connection between the first end and the second end of the capacitor unit under the control of the signal input at the third signal terminal.

9. The backlight control circuit according to claim 6, wherein, The luminous flux sensing sub-circuit further includes: An inverting operational amplifier, the non-inverting input terminal of the inverting operational amplifier is connected to a ground signal, the inverting input terminal of the inverting operational amplifier is coupled to the output terminal of the integrator, and the output terminal of the inverting operational amplifier is coupled to the first control signal output terminal.

10. A control method for a backlight control circuit, applied to the backlight control circuit according to any one of claims 1 to 9, the backlight control circuit comprising: A luminous flux sensing sub-circuit and a control sub-circuit; The control method includes: In the acquisition stage, the luminous flux sensing sub-circuit senses the luminous flux received by the display device in its environment, obtains a first control signal related to the luminous flux, and outputs the first control signal from the first control signal output terminal of the luminous flux sensing sub-circuit; the N second control signal output terminals corresponding to the N second sub-units provide valid second control signals in a time-sharing manner, and the valid second control signals control the electrical connection between the conduction signal input terminal and the output terminal of the corresponding second sub-unit; when the first control signal and the conduction threshold of the first sub-unit conform to a corresponding relationship, the first sub-unit conducts the electrical connection between the output terminal of the second sub-unit and the backlight control signal output terminal.

11. The control method for the backlight control circuit according to claim 10, wherein, The first sub-unit includes a first transistor, the second sub-unit includes a second transistor, a gate of the first transistor is coupled to the first control signal output terminal, a first pole of the first transistor is coupled to a second pole of the second transistor, and a second pole of the first transistor is coupled to the backlight control signal output terminal; a gate of the second transistor is coupled to a corresponding second control signal output terminal, and a first pole of the second transistor is coupled to the signal input terminal; During the acquisition stage, a valid second control signal controls the corresponding second transistor to turn on; When a correspondence exists between the first control signal and the conduction threshold of the first transistor, the first transistor turns on.

12. A display device, comprising the backlight control circuit according to any one of claims 1 to 9, wherein the display device further comprises: A coupled backlight driving circuit and a backlight source; The backlight driving circuit is further coupled to the backlight control signal output terminal, and the backlight driving circuit is configured to output a corresponding backlight driving signal to the backlight source under the control of the backlight control signal output from the backlight control signal output terminal.

Images