Backlight module and display device

Abstract

The invention provides a backlight module and a display device.The backlight module comprises a backlight lamp, a backlight driving circuit, a key and a key switching circuit, the key and the key switching circuit are connected with the backlight driving circuit, the backlight lamp comprises a second lamp string and a first lamp string surrounding the second lamp string, the backlight driving circuit is connected with the first lamp string, and the key switching circuit is connected with the second lamp string. The second lamp string inputs a first driving voltage and displays a first brightness, when multiple key pressing actions occur on the key, the key switching circuit alternately outputs a first level signal and a second level signal, and the backlight driving circuit is controlled to alternately output the first driving voltage and the second driving voltage; therefore, the first lamp string displays the first brightness and the second brightness respectively, the second brightness is smaller than the first brightness, the backlight module provides global backlight or local backlight, regional light control of the display panel is achieved, hardware control is achieved through the key switching circuit and the backlight driving circuit, and the light control switching efficiency is improved.

Description

Technical Field

[0001] This invention belongs to the field of display technology, and particularly relates to a backlight module and a display device. Background Technology

[0002] The display module can achieve global or local display. Through regional light control technology, the backlight module can be divided into multiple independent control areas. The brightness of each area can be adjusted according to the content of the screen to achieve global or local display, and achieve high contrast and dynamic range display.

[0003] However, the existing local dimming control method mainly adopts system software. Through the system software menu, multiple operations such as "display settings - image mode - local dimming" are performed, with a corresponding delay of 1 to 2 seconds. Moreover, when the system freezes or the driver malfunctions, the function switching fails, which cannot meet the user's needs for instant switching and convenient operation, resulting in low switching efficiency. Summary of the Invention

[0004] The purpose of this invention is to provide a backlight module that solves the problem of low switching efficiency in traditional backlight modules.

[0005] A first aspect of this invention provides a backlight module, comprising:

[0006] The backlight includes a first light string and a second light string, the first light string is arranged around the second light string, the input terminal of the second light string is used to input a first driving voltage, and the output terminals of the first light string and the second light string are grounded. A backlight driving circuit is connected to the input terminal of the first light string. The backlight driving circuit is triggered by a first level signal to output the first driving voltage to the first light string, or triggered by a second level signal to output the second driving voltage to the first light string, wherein the second driving voltage is less than the first driving voltage. button; The button conversion circuit is connected to the button and the backlight driving circuit respectively. The button conversion circuit is used to output a first level signal or a second level signal according to the user's single button press action, and alternately outputs the first level signal and the second level signal in a loop when different button actions are performed. The first level signal and the second level signal are high and low level signals to each other.

[0007] Optionally, the backlight driving circuit includes: A first switching circuit, wherein the input terminal of the first switching circuit is used to input the first driving voltage, and the output terminal of the first switching circuit is connected to the input terminal of the first light string, and the first switching circuit is triggered to be turned on by the first level signal and triggered to be turned off by the second level signal; The second switching circuit has an input terminal for inputting the second driving voltage and an output terminal connected to the input terminal of the first light string. The second switching circuit is triggered to turn on by the second level signal and triggered to turn off by the first level signal.

[0008] Optionally, the first switching circuit includes a first resistor, a second resistor, a third resistor, a fourth resistor, a first capacitor, a first transient diode, a first diode, a first transistor, and a first field-effect transistor; The first end of the first resistor constitutes the control terminal of the first switching circuit. The second end of the first resistor is connected to the base of the first transistor. The emitter of the first transistor, the source of the first field-effect transistor, the first end of the first transient diode, and the first end of the first capacitor are connected and used to input the first driving voltage. The second end of the first capacitor is grounded. The collector of the first transistor is connected to the first end of the second resistor. The second end of the second resistor, the first end of the third resistor, and the gate of the first field-effect transistor are connected. The second end of the third resistor is grounded. The second end of the first field-effect transistor, the second end of the first transient diode, the cathode of the first diode, and the first end of the fourth resistor are connected. The anode of the first diode is grounded. The second end of the fourth resistor constitutes the output terminal of the first switching circuit.

[0009] Optionally, the second switching circuit includes a fifth resistor, a sixth resistor, a seventh resistor, a second transient diode, a second diode, a second transistor, and a second field-effect transistor; The first end of the fifth resistor constitutes the control terminal of the second switching circuit. The second end of the fifth resistor is connected to the base of the second transistor. The collector of the second transistor is connected to the first end of the sixth resistor. The emitter of the second transistor is grounded. The second end of the sixth resistor, the first end of the seventh resistor, and the gate of the second field-effect transistor are connected. The drain of the second field-effect transistor, the second end of the seventh resistor, the first end of the second transient diode, and the cathode of the second diode are connected and used to input the second driving voltage. The source of the second field-effect transistor and the second end of the second transient diode are connected to constitute the output terminal of the second switching circuit. The anode of the second diode is grounded.

[0010] Optionally, the key switching circuit includes an eighth resistor, a ninth resistor, a tenth resistor, an eleventh resistor, a twelfth resistor, a thirteenth resistor, a second capacitor, a third capacitor, a third transistor, and a fourth transistor; The emitter of the third transistor is connected to the first end of the eighth resistor and used to input a positive voltage. The base of the third transistor, the second end of the eighth resistor, and the first end of the ninth resistor are connected. The collector of the third transistor and the first end of the tenth resistor are connected to form the signal output terminal of the button conversion circuit. The second end of the ninth resistor, the collector of the fourth transistor, and the first end of the eleventh resistor are connected. The second end of the eleventh resistor, the first end of the second capacitor, and the first end of the button are connected. The second end of the button, the second end of the tenth resistor, the first end of the twelfth resistor, and the first end of the third capacitor are connected. The second end of the twelfth resistor, the first end of the thirteenth resistor, and the base of the fourth transistor are connected. The second end of the second capacitor, the second end of the third capacitor, the second end of the thirteenth resistor, and the emitter of the fourth transistor are connected.

[0011] Optionally, the backlight module further includes: The first power switch has an input terminal for inputting the first driving voltage, and its output terminal, the input terminal of the first switching circuit, and the input terminal of the second lamp string are connected. The first power switch is triggered to turn on by a first power control signal and triggered to turn off by a second power control signal. The second power switch has an input terminal for inputting the second driving voltage and an output terminal connected to the input terminal of the second switching circuit. The second power switch is triggered to turn on by a third power control signal and triggered to turn off by a fourth power control signal. The key switching circuit includes: The level switching circuit is used to output one of the following signals according to a single key press by the user: a first key signal, a second key signal, and a high-impedance signal, and to alternately and cyclically output the first key signal, the second key signal, and the high-impedance signal during different key presses. The controller is connected to the first power switch, the second power switch, the level switching circuit, and the backlight driving circuit, respectively. The controller is used to output the second level signal, the second power control signal, and the third power control signal when receiving the first button signal, or to output the first level signal, the first power control signal, and the fourth power control signal when receiving the second button signal, or to output the second power control signal and the fourth power control signal when receiving the high impedance signal.

[0012] Optionally, the level switching circuit includes a fourteenth resistor, a fifteenth resistor, a sixteenth resistor, a seventeenth resistor, an eighteenth resistor, a nineteenth resistor, a twentieth resistor, a twenty-first resistor, a twenty-second resistor, a twenty-third resistor, a twenty-fourth resistor, a twenty-fifth resistor, a twenty-sixth resistor, a twenty-seventh resistor, a third diode, a fourth diode, a fifth diode, a sixth diode, a seventh diode, an eighth diode, a ninth diode, a third capacitor, a fourth capacitor, a fifth transistor, a sixth transistor, a seventh transistor, an eighth transistor, and a ninth transistor; The anode of the third diode is connected to the emitter of the sixth transistor and used to input a positive voltage. The cathode of the third diode, the first terminal of the fourteenth resistor, and the emitter of the fifth transistor are connected. The second terminal of the fourteenth resistor, the collector of the seventh transistor, the anode of the fourth diode, the base of the fifth transistor, and the anode of the eighth diode are connected. The base of the sixth transistor is connected to the first terminal of the fifteenth resistor. The second terminal of the fifteenth resistor, the cathode of the fifth diode, the second terminal of the twenty-second resistor, and the collector of the ninth transistor are connected. The first terminals of the 25th resistor and the 26th resistor are connected together and connected to the first signal terminal of the controller. The collector of the 6th transistor and the emitter of the 7th transistor are connected. The base of the 7th transistor and the first terminal of the 27th resistor are connected. The second terminal of the 27th resistor, the first terminal of the 16th resistor, and the first terminal of the 4th capacitor are connected. The second terminal of the 16th resistor, the first terminal of the 18th resistor, the second terminal of the 17th resistor, the collector of the 8th transistor, and the cathode of the 9th diode are connected together and connected to the second signal terminal of the controller. The second terminal of the fourth capacitor, the second terminal of the eighteenth resistor, and the second terminal of the twenty-fifth resistor are connected and used to input a positive voltage. The cathode of the fourth diode is connected to the first terminal of the seventeenth resistor. The collector of the fifth transistor, the first terminal of the nineteenth resistor, and the first terminal of the twentieth resistor are connected. The second terminal of the nineteenth resistor, the anode of the seventh diode, and the anode of the ninth diode are connected. The cathode of the seventh diode, the first terminal of the twenty-third resistor, and the first terminal of the button are connected. The second terminal of the button, the first terminal of the third capacitor, and the second terminal of the twenty-sixth resistor are connected. The second terminal of the twentieth resistor, the anode of the fifth diode, and the anode of the sixth diode are connected. The cathode of the sixth diode, the first terminal of the twenty-first resistor, and the base of the eighth transistor are connected. The second terminal of the twenty-first resistor and the emitter of the eighth transistor are grounded. The second terminal of the twenty-third resistor, the first terminal of the twenty-fourth resistor, and the base of the ninth transistor are connected. The emitter of the ninth transistor and the second terminal of the twenty-fourth resistor are grounded. The cathode of the eighth diode and the first terminal of the twenty-second resistor are connected.

[0013] Optionally, the first light string includes a plurality of LEDs connected in series, and the second light string includes a plurality of LEDs connected in series, wherein the plurality of LEDs in the first light string and the plurality of LEDs in the second light string are arranged in an array.

[0014] A second aspect of the present invention provides a display device including a display panel and a backlight module as described above, wherein the backlight module and the display panel are disposed opposite to each other.

[0015] Optionally, the display device further includes a housing, and the buttons of the backlight module are located on the back or side of the housing.

[0016] The beneficial effects of the embodiments of the present invention compared with the prior art are as follows: The backlight module includes a backlight lamp, a backlight driving circuit, a button, and a button conversion circuit. The button, the button conversion circuit, and the backlight driving circuit are connected. The backlight lamp includes a second light string and a first light string surrounding the second light string. The backlight driving circuit is connected to the first light string. The second light string receives a first driving voltage and displays a first brightness. When the button is pressed multiple times, the button conversion circuit alternately outputs a first level signal and a second level signal. The backlight driving circuit is controlled to alternately output the first driving voltage and the second driving voltage, so that the first light string displays the first brightness and the second brightness respectively. The second brightness is less than the first brightness, so that the backlight module provides global backlight or local backlight, realizing regional light control of the display panel. Furthermore, the use of the button conversion circuit and the backlight driving circuit to achieve hardware control improves the light control switching efficiency. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the first structure of the backlight module provided in Embodiment 1 of the present invention; Figure 2 This is a schematic diagram of a second structure of the backlight module provided in Embodiment 1 of the present invention; Figure 3 These are schematic diagrams of the display devices provided in Embodiments 1 and 4 of the present invention; Figure 4 This is a schematic diagram of the backlight structure provided in Embodiment 1 of the present invention; Figure 5 This is a schematic diagram of a third structure of the backlight module provided in Embodiment 1 of the present invention; Figure 6 This is a circuit diagram of the backlight driving circuit provided in Embodiment 2 of the present invention; Figure 7 This is a circuit diagram of the key conversion circuit provided in Embodiment 2 of the present invention; Figure 8 This is a schematic diagram of the backlight module provided in Embodiment 3 of the present invention; Figure 9 This is a circuit diagram of the level switching circuit provided in Embodiment 3 of the present invention.

[0018] The figures in the diagram are labeled as follows: 1. Display device; 100. Backlight module; 200. Display panel; 300. Housing; 10. Backlight lamp; 11. First LED string; 12. Second LED string; 20. Button; 30. Button switching circuit; 40. Backlight driving circuit; 50. First power switch; 60. Second power switch; 31. Level switching circuit; 32. Controller; 41. First switching circuit; 42. Second switching circuit; VIN1, first driving voltage; VIN2, second driving voltage; OUT1, first level switching signal; OUT2, second level switching signal; VCC, positive voltage; R1, First resistor; R2, Second resistor; R3, Third resistor; R4, Fourth resistor; R5, Fifth resistor; R6, Sixth resistor; R7, Seventh resistor; R8, Eighth resistor; R9, Ninth resistor; R10, Tenth resistor; R11, Eleventh resistor; R12, Twelfth resistor; R13, Thirteenth resistor; R14, Fourteenth resistor; R15, Fifteenth resistor; R16, Sixteenth resistor; R17, Seventeenth resistor; R18, Eighteenth resistor; R19, Nineteenth resistor; R20, Twentieth resistor; R21, Twenty-first resistor; R22, Twenty-second resistor; R23, Twenty-third resistor; R24, Twenty-fourth resistor; R25, Twenty-fifth resistor; R26, Twenty-sixth resistor; R27 27. Resistor; C1, Capacitor 1; C2, Capacitor 2; C3, Capacitor 3; C4, Capacitor 4; K1, Transistor 1; K2, Transistor 2; K3, Transistor 3; K4, Transistor 4; K5, Transistor 5; K6, Transistor 6; K7, Transistor 7; K8, Transistor 8; K9, Transistor 9; D1, Diode 1; D2, Diode 2; D3, Diode 3; D4, Diode 4; D5, Diode 5; D6, Diode 6; D7, Diode 7; D8, Diode 8; D9, Diode 9; Q1, Field-Effect Transistor 1; Q2, Field-Effect Transistor 2; ZD1, Transient Diode 1; ZD2, Transient Diode 2. Detailed Implementation

[0019] To make the technical problems to be solved, the technical solutions, and the beneficial effects of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the present invention and are not intended to limit the present invention.

[0020] The terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified.

[0021] Example 1 A first aspect of this invention provides a backlight module 100, such as... Figure 3 As shown, the backlight module 100 is disposed opposite to the display panel 200 and provides backlight for the display panel 200. The display panel 200 may be a liquid crystal display panel 200. The backlight module 100 and the display panel 200 constitute the display device 1.

[0022] To achieve local dimming and backlight zone brightness control, in this embodiment, as follows: Figure 1 and Figure 2 As shown, the backlight module 100 includes: The backlight 10 includes a first light string 11 and a second light string 12. The first light string 11 is arranged around the second light string 12. The input terminal of the second light string 12 is used to input a first driving voltage VIN1. The output terminals of the first light string 11 and the second light string 12 are grounded. The backlight driving circuit 40 is connected to the input terminal of the first lamp string 11. The backlight driving circuit 40 is triggered by a first level signal to output a first driving voltage VIN1 to the first lamp string 11, or is triggered by a second level signal to output a second driving voltage VIN2 to the first lamp string 11. The second driving voltage VIN2 is less than the first driving voltage VIN1. Button 20; The button conversion circuit 30 is connected to the button 20 and the backlight driving circuit 40 respectively. The button conversion circuit 30 is used to output a first level signal or a second level signal according to the user's single button press action on the button 20. The first level signal and the second level signal are alternately output in a loop when different button actions are performed. The first level signal and the second level signal are high and low level signals to each other.

[0023] In this embodiment, button 20 is used to realize the regional light control function and the backlight zone brightness control. Button 20 can adopt an ergonomic curved keycap design. Button 20 can be set at the corresponding position of the backlight module 100 or the corresponding position of the display device 1. In an optional embodiment, the display device 1 further includes a housing 300, and the button 20 of the backlight module 100 is set on the back or side of the housing 300, such as... Figure 3As shown, the button 20 can be located at the bottom center of the housing 300 of the display device 1, and is equidistant from the left and right edges, or it can be located on the right side of the bottom frame. The button 20 is flush with the housing 300 and slightly protrudes, which combines convenient operation and overall appearance.

[0024] This is used to enable or disable local dimming based on display requirements. For example, when a user is typing or performing other operations against a completely black background and needs to disable local dimming, a short press of button 20 activates the button switching circuit 30 to output a first-level signal. Figure 1 As shown, the backlight driving circuit 40 switches the output of the first driving voltage VIN1 to the first LED string 11. Both the first LED string 11 and the second LED string 12 receive the first driving voltage VIN1, and the first LED string 11 and the second LED string 12 exhibit the same first brightness. The backlight switches to a full-area constant-on state, and correspondingly, the display panel 200 is in full-screen display. In this way, when performing operations such as document editing against a dark or completely black background, the halo phenomenon caused by regional light control can be effectively eliminated, reducing visual fatigue from prolonged use of the eyes. At the same time, it ensures the uniformity of the backlight across the entire area, making it suitable for scenarios with high requirements for visual comfort, such as office work.

[0025] When local dimming is needed, such as in a light white or white background office setting, button 20 can be pressed briefly again. The button switching circuit 30 will then switch to output a second-level signal. Figure 2 As shown, the second level signal controls the backlight driving circuit 40 to switch the output of the second driving voltage VIN2 to the first lamp string 11. The second driving voltage VIN2 is less than the first driving voltage VIN1. Correspondingly, the brightness of the outer first lamp string 11 is less than the brightness of the second lamp string 12. Correspondingly, the brightness of the periphery of the display panel 200 is lower, and the brightness of the central area is higher. This achieves a smooth transition from the high brightness area to the surrounding low brightness area, alleviates the halo problem from the root, enhances the details and brightness contrast of the dark areas of the image, and at the same time reduces the power consumption of the display device 1.

[0026] By setting up button 20, button conversion circuit 30 and backlight driving circuit 40, the backlight module 100 can be controlled in different areas, allowing it to switch between inner and outer ring brightness modes or inner and outer ring brightness modes, achieving precise adaptation to different display effects in different scenarios. At the same time, the use of hardware circuitry to achieve regional light control eliminates the need for additional control components. Real-time feedback and transmission of signals enable one-button control of regional light control, improving the efficiency of light control.

[0027] The button conversion circuit 30 can adopt a corresponding signal conversion circuit. The signal conversion circuit sequentially switches and outputs different level signals according to the button action of the button 20, thereby realizing the opening and closing of the area light control of the backlight module 100.

[0028] The backlight driving circuit 40 can adopt a corresponding switching circuit and switch the output of the corresponding first driving voltage VIN1 or second driving voltage VIN2 according to the received level signal.

[0029] In an optional embodiment, the backlight driving circuit 40 includes: The first switching circuit 41 has an input terminal for inputting a first driving voltage VIN1, and an output terminal connected to the input terminal of the first lamp string 11. The first switching circuit 41 is triggered to turn on by a first level signal and triggered to turn off by a second level signal. The second switching circuit 42 has an input terminal for inputting the second driving voltage VIN2, and an output terminal connected to the input terminal of the first lamp string 11. The second switching circuit 42 is turned on by a second level signal and turned off by a first level signal.

[0030] In this embodiment, when button 20 is pressed briefly, button switching circuit 30 can switch the output of a first level signal according to the button action of button 20. The first level signal triggers the output to the first switch circuit 41 and the second switch circuit 42. The first level signal triggers the first switch circuit 41 to turn on and triggers the second switch circuit 42 to turn off. The first driving voltage VIN1 is switched to the output of the second light string 12. Both the first light string 11 and the second light string 12 receive the first driving voltage VIN1. The first light string 11 and the second light string 12 present the same first brightness. The backlight switches to a full-area constant-on state. Correspondingly, the display panel 200 is in full-screen display. In this way, when performing operations such as document editing against a dark or completely black background, the halo phenomenon caused by regional light control can be effectively eliminated, reducing visual fatigue from prolonged use of the eyes. At the same time, it ensures the uniformity of the backlight across the entire area, which is suitable for scenarios with high requirements for visual comfort, such as office work.

[0031] When button 20 is pressed again, button switching circuit 30 switches to output a second level signal. The second level signal controls the second switching circuit 42 to turn on and the first switching circuit 41 to turn off. The second switching circuit 42 switches to output a second driving voltage VIN2 to the first light string 11. The second driving voltage VIN2 is less than the first driving voltage VIN1. Correspondingly, the brightness of the outer first light string 11 is less than the brightness of the second light string 12. Correspondingly, the brightness of the periphery of the display panel 200 is lower, and the brightness of the central area is higher. This achieves a smooth transition from the high-brightness area to the surrounding low-brightness area, alleviates the halo problem from the root, enhances the details and brightness contrast of the dark areas of the image, and reduces the power consumption of the display device 1.

[0032] The first switching circuit 41 and the second switching circuit 42 can use corresponding switching transistors and other auxiliary components.

[0033] The first light string 11 and the second light string 12 can be composed of multiple LEDs. In an optional embodiment, the first light string 11 includes multiple LEDs connected in series, and the second light string 12 includes multiple LEDs connected in series. The multiple LEDs of the first light string 11 and the multiple LEDs of the second light string 12 are arranged in an array, for example... Figure 4 As shown, the first light string 11 may include the first LED LED1, the second LED LED2, the third LED LED3, the fourth LED LED4, the fifth LED LED5, the sixth LED LED6, the fifteenth LED LED15, the sixteenth LED LED16, the twenty-fifth LED LED25, the twenty-sixth LED LED26, the twenty-seventh LED LED27, the twenty-first LED LED21, the twentieth LED LED20, the eleventh LED LED11, and the tenth LED LED10, which are connected in series.

[0034] The second light string 12 may include the ninth LED (LED9), the eighth LED (LED8), the seventh LED (LED7), the fourteenth LED (LED14), the thirteenth LED (LED13), the twelfth LED (LED12), the nineteenth LED (LED19), the eighteenth LED (LED18), the seventeenth LED (LED17), the twenty-fourth LED (LED24), the twenty-third LED (LED23), and the twenty-second LED (LED22) connected in series. The multiple LED arrays are arranged such that the multiple LEDs of the first light string 11 surround the backlight module 100, and the multiple LEDs of the second light string 12 are located in the middle area of ​​the backlight module 100.

[0035] The beneficial effects of the embodiments of the present invention compared with the prior art are as follows: The backlight module 100 includes a backlight lamp 10, a backlight driving circuit 40, a button 20, and a button conversion circuit 30. The button 20, the button conversion circuit 30, and the backlight driving circuit 40 are connected. The backlight lamp 10 includes a second light string 12 and a first light string 11 surrounding the second light string 12. The backlight driving circuit 40 is connected to the first light string 11. The second light string 12 receives a first driving voltage VIN1 and displays a first brightness. When the button 20 is pressed multiple times, the button conversion circuit 30 alternately outputs a first level signal and a second level signal. The backlight driving circuit 40 is then controlled to alternately output the first driving voltage VIN1 and the second driving voltage VIN2, thereby causing the first light string 11 to display a first brightness and a second brightness respectively. The second brightness is less than the first brightness, thereby enabling the backlight module 100 to provide global backlight or local backlight, realizing regional light control of the display panel 200. Furthermore, the button conversion circuit 30 and the backlight driving circuit 40 are used to achieve hardware control, improving the efficiency of light control switching.

[0036] Example 2 In one optional embodiment, in order to achieve the anti-shake and anti-long-press functions of button 20 and avoid accidental triggering, in one optional embodiment, such as Figure 6 As shown, the first switching circuit 41 includes a first resistor R1, a second resistor R2, a third resistor R3, a fourth resistor R4, a first capacitor C1, a first transient diode ZD1, a first diode D1, a first transistor K1, and a first field-effect transistor Q1. The first end of the first resistor R1 forms the control terminal of the first switching circuit 41. The second end of the first resistor R1 is connected to the base of the first transistor K1. The emitter of the first transistor K1, the source of the first field-effect transistor Q1, the first end of the first transient diode ZD1, and the first end of the first capacitor C1 are connected and used to input the first driving voltage VIN1. The second end of the first capacitor C1 is grounded. The collector of the first transistor K1 and the first end of the second resistor R2 are connected. The second end of the second resistor R2, the first end of the third resistor R3, and the gate of the first field-effect transistor Q1 are connected. The second end of the third resistor R3 is grounded. The second end of the first field-effect transistor Q1, the second end of the first transient diode ZD1, the cathode of the first diode D1, and the first end of the fourth resistor R4 are connected. The anode of the first diode D1 is grounded. The second end of the fourth resistor R4 forms the output terminal of the first switching circuit 41.

[0037] The second switching circuit 42 includes a fifth resistor R5, a sixth resistor R6, a seventh resistor R7, a second transient diode ZD2, a second diode D2, a second transistor K2, and a second field-effect transistor Q2; The first end of the fifth resistor R5 constitutes the control terminal of the second switching circuit 42. The second end of the fifth resistor R5 is connected to the base of the second transistor K2. The collector of the second transistor K2 is connected to the first end of the sixth resistor R6. The emitter of the second transistor K2 is grounded. The second end of the sixth resistor R6, the first end of the seventh resistor R7, and the gate of the second field-effect transistor Q2 are connected. The drain of the second field-effect transistor Q2, the second end of the seventh resistor R7, the first end of the second transient diode ZD2, and the cathode of the second diode D2 are connected and used to input the second driving voltage VIN2. The source of the second field-effect transistor Q2 and the second end of the second transient diode ZD2 are connected to constitute the output terminal of the second switching circuit 42. The anode of the second diode D2 is grounded.

[0038] like Figure 7 As shown, the key switching circuit 30 includes an eighth resistor R8, a ninth resistor R9, a tenth resistor R10, an eleventh resistor R11, a twelfth resistor R12, a thirteenth resistor R13, a second capacitor C2, a third capacitor C3, a third transistor K3, and a fourth transistor K4. The emitter of the third transistor K3 is connected to the first end of the eighth resistor R8 and used to input the positive voltage VCC. The base of the third transistor K3, the second end of the eighth resistor R8, and the first end of the ninth resistor R9 are connected. The collector of the third transistor K3 and the first end of the tenth resistor R10 are connected to form the signal output terminal of the button conversion circuit 30. The second end of the ninth resistor R9, the collector of the fourth transistor K4, and the first end of the eleventh resistor R11 are connected. The second end of the eleventh resistor R11, the first end of the second capacitor C2, and the first end of the button 20 are connected. The second end of the button 20, the second end of the tenth resistor R10, the first end of the twelfth resistor R12, and the first end of the third capacitor C3 are connected. The second end of the twelfth resistor R12, the first end of the thirteenth resistor R13, and the base of the fourth transistor K4 are connected. The second end of the second capacitor C2, the second end of the third capacitor C3, the second end of the thirteenth resistor R13, and the emitter of the fourth transistor K4 are connected.

[0039] In this embodiment, the output level of the key conversion circuit 30 occurs at the moment the key 20 is contacted. When the key 20 is pressed, whether the key 20 is jittering or pressed for a long time, the output level of the key conversion circuit 30 will not change.

[0040] When the button switching circuit 30 is initially powered on, the base and emitter of the third transistor K3 are short-circuited by the eighth resistor R8, and the third transistor K3 is in the off state. Correspondingly, the base and emitter of the fourth transistor K4 are short-circuited by the thirteenth resistor R13, and the fourth transistor K4 is in the off state. Correspondingly, the button switching circuit 30 switches to output a low-level signal. After power-on, the second capacitor C2 is slowly charged through the eleventh resistor R11, and the terminal voltage of the second capacitor C2 is close to the positive voltage VCC.

[0041] When button 20 is pressed, the second capacitor C2 discharges rapidly to the base of the third transistor K3 through the twelfth resistor R12, driving the fourth transistor K4 to quickly enter saturation. The fourth transistor K4 is triggered to conduct, and correspondingly, the fourth transistor K4 transmits a low level to the third transistor K3, triggering the third transistor K3 to conduct. Correspondingly, the output of the button conversion circuit 30 switches to a high level, that is, the button conversion circuit 30 switches to output a high-level signal, which is the first level signal.

[0042] When the second capacitor C2 discharges until the emitter junction voltage drop of the fourth transistor K4 reaches the threshold voltage (which can be 0.7V), the discharge process stops. At this point, if button 20 is released, the second capacitor C2 will continue to discharge until the saturation voltage drop of the fourth transistor K4 stabilizes (which can be 0.3V).

[0043] When button 20 is pressed again, the base level of the fourth transistor K4 abruptly switches to a low level, and the fourth transistor K4 switches from a saturated state to a cutoff state. Correspondingly, the base of the third transistor K3 is at a high level, and the third transistor K3 switches to a cutoff state. The output of the button conversion circuit 30 switches to a low level, that is, the button conversion circuit 30 switches to output a low-level signal, which is the second level signal.

[0044] Among them, the resistance of the eleventh resistor R11 is greater than that of the tenth resistor R10, the twelfth resistor R12, and the thirteenth resistor R13. When the voltage across the second capacitor C2 is stable, the current through the eleventh resistor R11 is insufficient to change the conduction state of the fourth transistor K4. Only when the button 20 is released does the second capacitor C2 continuously accumulate charge through the eleventh resistor R11. When the button 20 is pressed again, the charge stored in the second capacitor C2 is quickly released to form a large current, which can drive the switching state of the fourth transistor K4 to reverse. When the button 20 is bounced or pressed for a long time, no large current is formed, that is, the switching state of the fourth transistor K4 will not change. This solves the problem of button 20 bounce and long press skipping, and avoids the button switching circuit 30 being triggered erroneously.

[0045] Correspondingly, when the button switching circuit 30 switches to output the first level signal, the first transistor K1 is triggered to turn off, and the second transistor K2 is triggered to turn on. At this time, the gate of the first field-effect transistor Q1 receives a low level, the first field-effect transistor is triggered to turn on and switch the output of the first driving voltage VIN1 to the first lamp string 11, while the second field-effect transistor Q2 receives a low level, the second field-effect transistor Q2 is turned off, and the second driving voltage VIN2 is cut off.

[0046] Both the first LED string 11 and the second LED string 12 receive the first driving voltage VIN1, and the first LED string 11 and the second LED string 12 exhibit the same first brightness. The backlight switches to a constant-on state across the entire area, and correspondingly, the display panel 200 displays in full screen. In this way, when performing operations such as document editing against a dark or completely black background, the halo phenomenon caused by local light control can be effectively eliminated, reducing visual fatigue from prolonged use of the eyes. At the same time, it ensures uniformity of backlighting across the entire area, making it suitable for scenarios with high requirements for visual comfort, such as office work.

[0047] When button 20 is pressed again, button switching circuit 30 switches to output a low-level signal, triggering the first transistor K1 to conduct and the second transistor K2 to turn off. The gate of the first field-effect transistor Q1 receives a high level and is triggered to turn off. The first switching circuit 41 cuts off the output of the first driving voltage VIN1, while the gate of the second field-effect transistor Q2 receives a high level and is triggered to conduct, switching the output of the second driving voltage VIN2 to the first LED string 11. The second driving voltage VIN2 is less than the first driving voltage VIN1. Correspondingly, the brightness of the outer first LED string 11 is less than the brightness of the second LED string 12. Correspondingly, the brightness of the periphery of the display panel 200 is lower, and the brightness of the central area is higher. This achieves a smooth transition from the high-brightness area to the surrounding low-brightness area, fundamentally alleviating the halo problem, enhancing the details and brightness contrast in the dark areas of the image, and reducing the power consumption of the display device 1.

[0048] Example 3 To improve the display mode of the backlight module 100 and enable multi-functional control of the buttons 20, in an optional embodiment, such as Figure 8 As shown, the backlight module 100 also includes: The first power switch 50 has an input terminal for inputting the first driving voltage VIN1. The output terminal of the first power switch 50 is connected to the input terminal of the first switching circuit 41 and the input terminal of the second lamp string 12. The first power switch 50 is turned on by triggering the first power control signal and turned off by triggering the second power control signal. The second power switch 60 has an input terminal for inputting the second driving voltage VIN2, and its output terminal is connected to the input terminal of the second switching circuit 42. The second power switch 60 is turned on by a third power control signal and turned off by a fourth power control signal. The key switching circuit 30 includes: The level switching circuit 31 is used to output one of the following signals according to the user's single key press action on the key 20: first key signal, second key signal, and high impedance signal, and to alternately and cyclically output the first key signal, second key signal, and high impedance signal when different key press actions occur. The controller 32 is connected to the first power switch 50, the second power switch 60, the level switching circuit 31, and the backlight driving circuit 40 respectively. The controller 32 is used to output a second level signal, a second power control signal, and a third power control signal when receiving a first key signal, or to output a first level signal, a first power control signal, and a fourth power control signal when receiving a second key signal, or to output a second power control signal and a fourth power control signal when receiving a high impedance signal.

[0049] In this embodiment, button 20 can realize one-button multi-control function through button conversion circuit 30, that is, realize the control of area light control and power control. The user can press button 20 multiple times to turn the standby and area light control functions on and off.

[0050] When button 20 is pressed for the first time, level switching circuit 31 can switch to output a first button signal. When controller 32 receives the first button signal, controller 32 switches to output a second level signal to first switch circuit 41 and second switch circuit 42. At the same time, it switches to output a third power control signal and a second power control signal. Second power switch 60 is triggered and turned on, and transmits the second driving voltage VIN2 to second switch circuit 42. Second switch circuit 42 switches to output the second driving voltage VIN2. The second driving voltage VIN2 is less than the first driving voltage VIN1. Correspondingly, the brightness of the first LED string 11 is less than the brightness of the second LED string 12. Correspondingly, the brightness of the periphery of display panel 200 is lower, and the brightness of the central area is higher, thereby achieving a smooth transition from the high brightness area to the peripheral low brightness area.

[0051] When button 20 is pressed again, level switching circuit 31 switches to output a second button signal. When controller 32 receives the second button signal, controller 32 switches to output a first level signal to first switch circuit 41 and second switch circuit 42. At the same time, it switches to output a first power control signal and a fourth power control signal. First power switch 50 is triggered and conducts, and transmits the first driving voltage VIN1 to second switch circuit 42. First switch circuit 41 switches to output the first driving voltage VIN1. First light string 11 and second light string 12 both receive the first driving voltage VIN1. First light string 11 and second light string 12 present the same first brightness. Backlight switches to a full-area constant-on state. Correspondingly, display panel 200 is in full-screen display, ensuring full-area backlight uniformity and adapting to scenarios with high visual comfort requirements, such as office work.

[0052] When button 20 is pressed again, level switching circuit 31 switches to output high impedance signal. When controller 32 receives high impedance signal, it switches to output second power control signal and fourth power control signal. First power switch 50 and second power switch 60 are turned off at the same time. Backlight driving circuit 40 and backlight 10 are turned off as a whole, and backlight operation stops.

[0053] Button 20 can enable and disable area light control through button conversion circuit 30, and can also turn the backlight module 100 on or off. The backlight module 100 does not need to be equipped with an additional button 20 to control the power on and off of the backlight module 100, which simplifies the structure of the backlight module 100 and improves the operation integration.

[0054] The controller 32 can adopt a corresponding microprocessor, single-chip microcomputer or other structure, and the level switching circuit 31 can adopt a corresponding switch switching circuit.

[0055] In an alternative embodiment, such as Figure 9 As shown, in an optional embodiment, the level switching circuit 31 includes the fourteenth resistor R14, the fifteenth resistor R15, the sixteenth resistor R16, the seventeenth resistor R17, the eighteenth resistor R18, the nineteenth resistor R19, the twentieth resistor R20, the twenty-first resistor R21, the twenty-second resistor R22, the twenty-third resistor R23, the twenty-fourth resistor R24, the twenty-fifth resistor R25, the twenty-sixth resistor R26, the twenty-seventh resistor R27, the third diode D3, the fourth diode D4, the fifth diode D5, the sixth diode D6, the seventh diode D7, the eighth diode D8, the ninth diode D9, the third capacitor C3, the fourth capacitor C4, the fifth transistor K5, the sixth transistor K6, the seventh transistor K7, the eighth transistor K8, and the ninth transistor K9; The anode of the third diode D3 is connected to the emitter of the sixth transistor K6 and used to input the positive voltage VCC. The cathode of the third diode D3, the first terminal of the fourteenth resistor R14, and the emitter of the fifth transistor K5 are connected. The second terminal of the fourteenth resistor R14, the collector of the seventh transistor K7, the anode of the fourth diode D4, the base of the fifth transistor K5, and the anode of the eighth diode D8 are connected. The base of the sixth transistor K6 is connected to the first terminal of the fifteenth resistor R15. The second terminal of the fifteenth resistor R15, the cathode of the fifth diode D5, the second terminal of the twenty-second resistor R22, the collector of the ninth transistor K9, and the twentieth... The first terminal of resistor R25 and the first terminal of resistor R26 are connected together and connected to the first signal terminal of controller 32. The collector of transistor K6 and the emitter of transistor K7 are connected. The base of transistor K7 and the first terminal of resistor R27 are connected. The second terminal of resistor R27, the first terminal of resistor R16, and the first terminal of capacitor C4 are connected. The second terminal of resistor R16, the first terminal of resistor R18, the second terminal of resistor R17, the collector of transistor K8, and the cathode of diode D9 are connected together and connected to the second signal terminal of controller 32. The second terminal of the fourth capacitor C4, the second terminal of the eighteenth resistor R18, and the second terminal of the twenty-fifth resistor R25 are connected and used for input positive voltage VCC. The cathode of the fourth diode D4 is connected to the first terminal of the seventeenth resistor R17. The collector of the fifth transistor K5, the first terminal of the nineteenth resistor R19, and the first terminal of the twentieth resistor R20 are connected. The second terminal of the nineteenth resistor R19, the anode of the seventh diode D7, and the anode of the ninth diode D9 are connected. The cathode of the seventh diode D7, the first terminal of the twenty-third resistor R23, and the first terminal of the button 20 are connected. The second terminal of the button 20, the first terminal of the third capacitor C3, and the second terminal of the fourth diode C4 are connected to the first terminal of the seventh diode D7, the first terminal of the twenty-third resistor R23, and the first terminal of the button 20 are connected to the first terminal of the seventh diode D7, the first terminal of the twenty-third resistor R23, and the second ... seventh diode D7. The second end of resistor R26 is connected to the ground. The second end of resistor R20, the anode of diode D5, and the anode of diode D6 are connected to the ground. The cathode of diode D6, the first end of resistor R21, and the base of transistor K8 are connected to the ground. The second end of resistor R21 and the emitter of transistor K8 are grounded. The second end of resistor R23, the first end of resistor R24, and the base of transistor K9 are connected to the ground. The emitter of transistor K9 and the second end of resistor R24 ​​are grounded. The cathode of diode D8 and the first end of resistor R22 are connected to the ground.

[0056] In this embodiment, OUT1 is set as the first level switching signal and OUT2 is set as the second level switching signal. The first level switching signal OUT1 and the second level switching signal OUT2 constitute the first button signal, the second button signal and the high impedance signal.

[0057] When the level switching circuit 31 is initially powered on, the bases and emitters of the fifth transistor K5, the eighth transistor K8, and the ninth transistor K9 are all configured with reverse bias voltages. The fifth transistor K5, the eighth transistor K8, and the ninth transistor K9 are all in the off state. The collector of the ninth transistor K9 is in a high-impedance state, and the collector of the eighth transistor K8 is in a high-impedance state. That is, the first level switching signal OUT1 and the second level switching signal OUT2 are in a high-impedance state. At this time, the controller 32 receives two high-impedance states, which together form a high-impedance signal. The controller 32 switches the output of the second power control signal and the fourth power control signal. The first power switch 50 and the second power switch 60 are turned off, and the backlight driving circuit 40 and the backlight lamp 10 are turned off as a whole, stopping the backlight operation.

[0058] At the same time, the level switching circuit 31 enters the low-power standby mode, and the positive voltage VCC charges the third capacitor C3 to the positive voltage VCC through the third diode D3, the fourteenth resistor R14, the eighth diode D8, the twenty-second resistor R22, and the twenty-sixth resistor R26.

[0059] When button 20 is pressed for the first time, the third capacitor C3 discharges through the twenty-sixth resistor R26 and the collector of the ninth transistor K9. The base of the ninth transistor K9 meets the conduction threshold, and the ninth transistor K9 switches to the conducting state. At the same time, the ninth transistor K9 outputs a low level to the fifth transistor K5, triggering the fifth transistor K5 to conduct. The level of the collector of the ninth transistor K9 flips to a low level, and the level of the ninth diode D9 outputs a high level. That is, the first level switching signal OUT1 is a low level signal, and the second level switching signal OUT2 is a high level signal. Controller 3... When the controller 32 receives the high-level second-level switching signal OUT2 and the low-level first-level switching signal OUT1, it controls the activation of the area light control function, that is, switches the output of the second-level signal and the second power supply control signal. The second driving voltage VIN2 is output to the first lamp string 11. At the same time, the base of the eighth transistor K8 is triggered to turn off by a low level, the base of the seventh transistor K7 is triggered to turn off by a high level, the base of the sixth transistor K6 is triggered to turn on by a low level, and the third capacitor C3 discharges through the ninth transistor K9 to the saturation voltage drop of the ninth transistor K9.

[0060] When button 20 is pressed and closed for the second time, the base bias of transistor K9 disappears, and transistor K9 switches to the cutoff state. The first level switching signal OUT1 rises back to the high level. After receiving the high level, transistor K6 switches to the cutoff state. At the same time, the base of transistor K8 receives the high level and is triggered to conduct. The second level switching signal OUT2 switches to the low level. When controller 32 receives the low-level second level switching signal OUT2 and the high-level first level switching signal OUT1, controller 32 turns off the area light control function, that is, it outputs the first power control signal and the first level signal. The first switching circuit 41 switches to output the first driving voltage VIN1. The first light string 11 and the second light string 12 both receive the first driving voltage VIN1. The first light string 11 and the second light string 12 present the same first brightness. The backlight switches to the full-area constant-on state. Correspondingly, the display panel 200 is in full-screen display to ensure the uniformity of the backlight across the entire area, which is suitable for scenarios with high requirements for visual comfort, such as office work.

[0061] Meanwhile, the fourth capacitor C4 and the sixteenth resistor R16 form a delay unit, which delays the change in the base level of the seventh transistor K7, ensuring that the base of the seventh transistor K7 only drops to the conduction threshold after the sixth transistor K6 is completely turned off, thus avoiding the risk of common-mode conduction of the sixth transistor K6 and the seventh transistor K7.

[0062] When button 20 is pressed for the third time, transistor K9 switches from the off state to the on state, the first level switching signal OUT1 is pulled low, and transistor K6 is triggered to conduct. After the external button 20 is closed for the third time, the ninth transistor K9 returns to the saturated conduction state from the cutoff state. The seventh transistor K7 is still delayed by the delay unit composed of the fourth capacitor C4 and the sixteenth resistor R16. Finally, the fifth transistor K5 returns to the cutoff state due to the disappearance of the base bias. The fifth transistor K5, the eighth transistor K8 and the ninth transistor K9 switch to the cutoff state. At this time, the first level switching signal OUT1 and the second level switching signal OUT2 are reset to the high impedance state. The third capacitor C3 starts charging again. The circuit closed loop returns to the low power standby mode at the beginning of power-on. At this time, the controller 32 receives two high impedance states. The two high impedance states form a high impedance state signal. The controller 32 switches the output of the second power control signal and the fourth power control signal. The first power switch 50 and the second power switch 60 are turned off. The backlight driving circuit 40 and the backlight 10 are turned off as a whole, and the backlight operation stops.

[0063] Example 4 A second aspect of the present invention provides a display device 1, such as... Figure 3As shown, the display device 1 includes a display panel 200 and a backlight module 100. The specific structure of the backlight module 100 is as described in the above embodiments. Since the display device 1 adopts all the technical solutions of all the above embodiments, it has at least all the beneficial effects brought about by the technical solutions of the above embodiments, which will not be described in detail here.

[0064] The backlight module 100 is disposed opposite to the display panel 200 and provides backlight for the display panel 200. The display panel 200 may be a liquid crystal display panel 200. The backlight module 100 and the display panel 200 constitute the display device 1.

[0065] Button 20 is used to implement local dimming function and backlight zone brightness control. Button 20 can adopt an ergonomic curved keycap design. Button 20 can be set at a corresponding position on the backlight module 100 or a corresponding position on the display device 1. In an optional embodiment, the display device 1 further includes a housing 300, and the button 20 of the backlight module 100 is set on the back or side of the housing 300, such as... Figure 3 As shown, the button 20 can be located at the bottom center of the housing 300 of the display device 1, and is equidistant from the left and right edges, or it can be located on the right side of the bottom frame. The button 20 is flush with the housing 300 and slightly protrudes, which combines convenient operation and overall appearance.

[0066] The above-described embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention, and should all be included within the protection scope of the present invention.

Claims

1. A backlight module, characterized in that, include: The backlight includes a first light string and a second light string, the first light string is arranged around the second light string, the input terminal of the second light string is used to input a first driving voltage, and the output terminals of the first light string and the second light string are grounded. A backlight driving circuit is connected to the input terminal of the first light string. The backlight driving circuit is triggered by a first level signal to output the first driving voltage to the first light string, or triggered by a second level signal to output the second driving voltage to the first light string, wherein the second driving voltage is less than the first driving voltage. button; The button conversion circuit is connected to the button and the backlight driving circuit respectively. The button conversion circuit is used to output a first level signal or a second level signal according to the user's single button press action, and alternately outputs the first level signal and the second level signal in a loop when different button actions are performed. The first level signal and the second level signal are high and low level signals to each other.

2. The backlight module as described in claim 1, characterized in that, The backlight driving circuit includes: A first switching circuit, wherein the input terminal of the first switching circuit is used to input the first driving voltage, and the output terminal of the first switching circuit is connected to the input terminal of the first light string, and the first switching circuit is triggered to be turned on by the first level signal and triggered to be turned off by the second level signal; The second switching circuit has an input terminal for inputting the second driving voltage and an output terminal connected to the input terminal of the first light string. The second switching circuit is triggered to turn on by the second level signal and triggered to turn off by the first level signal.

3. The backlight module as described in claim 2, characterized in that, The first switching circuit includes a first resistor, a second resistor, a third resistor, a fourth resistor, a first capacitor, a first transient diode, a first diode, a first transistor, and a first field-effect transistor; The first end of the first resistor constitutes the control terminal of the first switching circuit. The second end of the first resistor is connected to the base of the first transistor. The emitter of the first transistor, the source of the first field-effect transistor, the first end of the first transient diode, and the first end of the first capacitor are connected and used to input the first driving voltage. The second end of the first capacitor is grounded. The collector of the first transistor is connected to the first end of the second resistor. The second end of the second resistor, the first end of the third resistor, and the gate of the first field-effect transistor are connected. The second end of the third resistor is grounded. The second end of the first field-effect transistor, the second end of the first transient diode, the cathode of the first diode, and the first end of the fourth resistor are connected. The anode of the first diode is grounded. The second end of the fourth resistor constitutes the output terminal of the first switching circuit.

4. The backlight module as described in claim 2, characterized in that, The second switching circuit includes a fifth resistor, a sixth resistor, a seventh resistor, a second transient diode, a second diode, a second transistor, and a second field-effect transistor; The first end of the fifth resistor constitutes the control terminal of the second switching circuit. The second end of the fifth resistor is connected to the base of the second transistor. The collector of the second transistor is connected to the first end of the sixth resistor. The emitter of the second transistor is grounded. The second end of the sixth resistor, the first end of the seventh resistor, and the gate of the second field-effect transistor are connected. The drain of the second field-effect transistor, the second end of the seventh resistor, the first end of the second transient diode, and the cathode of the second diode are connected and used to input the second driving voltage. The source of the second field-effect transistor and the second end of the second transient diode are connected to constitute the output terminal of the second switching circuit. The anode of the second diode is grounded.

5. The backlight module as described in claim 2, characterized in that, The key switching circuit includes an eighth resistor, a ninth resistor, a tenth resistor, an eleventh resistor, a twelfth resistor, a thirteenth resistor, a second capacitor, a third capacitor, a third transistor, and a fourth transistor; The emitter of the third transistor is connected to the first end of the eighth resistor and used to input a positive voltage. The base of the third transistor, the second end of the eighth resistor, and the first end of the ninth resistor are connected. The collector of the third transistor and the first end of the tenth resistor are connected to form the signal output terminal of the button conversion circuit. The second end of the ninth resistor, the collector of the fourth transistor, and the first end of the eleventh resistor are connected. The second end of the eleventh resistor, the first end of the second capacitor, and the first end of the button are connected. The second end of the button, the second end of the tenth resistor, the first end of the twelfth resistor, and the first end of the third capacitor are connected. The second end of the twelfth resistor, the first end of the thirteenth resistor, and the base of the fourth transistor are connected. The second end of the second capacitor, the second end of the third capacitor, the second end of the thirteenth resistor, and the emitter of the fourth transistor are connected.

6. The backlight module as described in claim 2, characterized in that, The backlight module also includes: The first power switch has an input terminal for inputting the first driving voltage, and its output terminal, the input terminal of the first switching circuit, and the input terminal of the second lamp string are connected. The first power switch is triggered to turn on by a first power control signal and triggered to turn off by a second power control signal. The second power switch has an input terminal for inputting the second driving voltage and an output terminal connected to the input terminal of the second switching circuit. The second power switch is triggered to turn on by a third power control signal and triggered to turn off by a fourth power control signal. The key switching circuit includes: The level switching circuit is used to output one of the following signals according to a single key press by the user: a first key signal, a second key signal, and a high-impedance signal, and to alternately and cyclically output the first key signal, the second key signal, and the high-impedance signal during different key presses. The controller is connected to the first power switch, the second power switch, the level switching circuit, and the backlight driving circuit, respectively. The controller is used to output the second level signal, the second power control signal, and the third power control signal when receiving the first button signal, or to output the first level signal, the first power control signal, and the fourth power control signal when receiving the second button signal, or to output the second power control signal and the fourth power control signal when receiving the high impedance signal.

7. The backlight module as described in claim 6, characterized in that, The level switching circuit includes the fourteenth resistor, the fifteenth resistor, the sixteenth resistor, the seventeenth resistor, the eighteenth resistor, the nineteenth resistor, the twentieth resistor, the twenty-first resistor, the twenty-second resistor, the twenty-third resistor, the twenty-fourth resistor, the twenty-fifth resistor, the twenty-sixth resistor, the twenty-seventh resistor, the third diode, the fourth diode, the fifth diode, the sixth diode, the seventh diode, the eighth diode, the ninth diode, the third capacitor, the fourth capacitor, the fifth transistor, the sixth transistor, the seventh transistor, the eighth transistor, and the ninth transistor; The anode of the third diode is connected to the emitter of the sixth transistor and used to input a positive voltage. The cathode of the third diode, the first terminal of the fourteenth resistor, and the emitter of the fifth transistor are connected. The second terminal of the fourteenth resistor, the collector of the seventh transistor, the anode of the fourth diode, the base of the fifth transistor, and the anode of the eighth diode are connected. The base of the sixth transistor is connected to the first terminal of the fifteenth resistor. The second terminal of the fifteenth resistor, the cathode of the fifth diode, the second terminal of the twenty-second resistor, and the collector of the ninth transistor are connected. The first terminals of the 25th resistor and the 26th resistor are connected together and connected to the first signal terminal of the controller. The collector of the 6th transistor and the emitter of the 7th transistor are connected. The base of the 7th transistor and the first terminal of the 27th resistor are connected. The second terminal of the 27th resistor, the first terminal of the 16th resistor, and the first terminal of the 4th capacitor are connected. The second terminal of the 16th resistor, the first terminal of the 18th resistor, the second terminal of the 17th resistor, the collector of the 8th transistor, and the cathode of the 9th diode are connected together and connected to the second signal terminal of the controller. The second terminal of the fourth capacitor, the second terminal of the eighteenth resistor, and the second terminal of the twenty-fifth resistor are connected and used to input a positive voltage. The cathode of the fourth diode is connected to the first terminal of the seventeenth resistor. The collector of the fifth transistor, the first terminal of the nineteenth resistor, and the first terminal of the twentieth resistor are connected. The second terminal of the nineteenth resistor, the anode of the seventh diode, and the anode of the ninth diode are connected. The cathode of the seventh diode, the first terminal of the twenty-third resistor, and the first terminal of the button are connected. The second terminal of the button, the first terminal of the third capacitor, and the second terminal of the twenty-sixth resistor are connected. The second terminal of the twentieth resistor, the anode of the fifth diode, and the anode of the sixth diode are connected. The cathode of the sixth diode, the first terminal of the twenty-first resistor, and the base of the eighth transistor are connected. The second terminal of the twenty-first resistor and the emitter of the eighth transistor are grounded. The second terminal of the twenty-third resistor, the first terminal of the twenty-fourth resistor, and the base of the ninth transistor are connected. The emitter of the ninth transistor and the second terminal of the twenty-fourth resistor are grounded. The cathode of the eighth diode and the first terminal of the twenty-second resistor are connected.

8. The backlight module as described in any one of claims 1 to 7, characterized in that, The first light string includes multiple LEDs connected in series, and the second light string includes multiple LEDs connected in series. The multiple LEDs in the first light string and the multiple LEDs in the second light string are arranged in an array.

9. A display device, characterized in that, It includes a display panel and a backlight module as described in any one of claims 1 to 8, wherein the backlight module and the display panel are disposed opposite to each other.

10. The display device as claimed in claim 9, characterized in that, The display device also includes a housing, and the buttons of the backlight module are located on the back or side of the housing.

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