Liquid crystal visual chart

Abstract

The liquid crystal visual chart comprises a liquid crystal screen, a backlight driving circuit, a photosensitive sensor and a controller, the liquid crystal screen comprises a backlight source and a liquid crystal layer, the backlight source provides backlight for the liquid crystal layer, and the backlight driving circuit is connected with the backlight source and can control voltage and current of the liquid crystal screen. The photosensitive sensor is arranged between the backlight source and the liquid crystal layer and can measure the intensity of backlight emitted by the backlight source and correspondingly output induction signals, and the controller is connected with the backlight driving circuit and the photosensitive sensor and can obtain the induction signals and output control signals to the backlight driving circuit. According to the liquid crystal visual chart, the controller can output the control signal to the backlight driving circuit according to the acquired sensing signal, and the backlight driving circuit controls the voltage and current of the liquid crystal screen to control the intensity of backlight emitted by the backlight source, so that the brightness of the liquid crystal screen is automatically adjusted; the brightness of the liquid crystal visual chart can be prevented from influencing the accuracy of vision measurement.

Description

Technical Field

[0001] The utility model relates to the field of medical instruments, in particular to a liquid crystal eye chart. Background Art

[0002] With the development of society, the detection and treatment methods for eye problems have been developed and improved. The eye chart is a chart used to measure vision. By using the eye chart to examine the subject, the initial situation of the subject's visual function can be simply and quickly understood, which is of great significance for the diagnosis and treatment of eye diseases.

[0003] In the medical field, higher requirements are placed on the performance and quality of eye charts. Current eye charts use electronic screens to display the corresponding content. According to market research data, the brightness of some eye charts decreases as they are used for a longer time, which will affect the accuracy of vision measurement. Utility Model Content

[0004] The utility model aims to provide a liquid crystal visual acuity chart which can automatically adjust the brightness of the liquid crystal screen to avoid affecting the accuracy of visual acuity measurement.

[0005] In order to achieve the above purpose, the utility model provides the following technical solutions:

[0006] A liquid crystal eye chart, comprising:

[0007] A liquid crystal screen for displaying sight marks, comprising a backlight source and a liquid crystal layer, wherein the backlight source is used to provide backlight to the liquid crystal layer;

[0008] A backlight driving circuit connected to the backlight source and controlling the voltage and current of the liquid crystal screen;

[0009] A photosensor disposed between the backlight source and the liquid crystal layer, for measuring the intensity of backlight emitted by the backlight source and outputting a sensing signal accordingly;

[0010] A controller is connected to the backlight driving circuit and the photosensor respectively, and acquires the sensing signal and outputs a control signal to the backlight driving circuit.

[0011] Optionally, the LCD screen is provided with a first interface and a second interface, the first interface is used to connect the backlight source, the backlight source is connected to the controller via the first interface, and the second interface is used to connect the photosensor, the photosensor is connected to the controller via the second interface.

[0012] Optionally, a light leakage hole is arranged on the LCD screen and corresponds to the backlight source and the liquid crystal layer, the photosensor is arranged corresponding to the light leakage hole or the photosensor extends into the light leakage hole, and the photosensor is used to measure the intensity of light transmitted from the light leakage hole.

[0013] Optionally, the photosensor includes a sensing circuit, and the sensing circuit is connected to the controller via a first line and a second line respectively, the first line is used for the sensing circuit to transmit a high level / low level signal to the controller, and the second line is used for the sensing circuit to transmit the sensing signal to the controller.

[0014] Optionally, the voltage provided by the backlight driving circuit to the liquid crystal screen remains unchanged, and the current provided to the liquid crystal screen changes, and the backlight intensity emitted by the backlight source changes with the current.

[0015] Optionally, the backlight driving circuit includes a driving chip and a first output terminal, a second output terminal, an input terminal and an enable terminal respectively connected to the driving chip;

[0016] The first output terminal and the second output terminal are respectively used to connect to the backlight source, the input terminal is used to input a pulse width modulation signal to the driver chip, and the enable terminal is used to enable the driver chip. When the enable terminal inputs a high-level signal to the driver chip, the first output terminal and the second output terminal output normally, and when the enable terminal inputs a low-level signal to the driver chip, the first output terminal and the second output terminal turn off the output.

[0017] Optionally, the backlight driving circuit further includes a field effect transistor, the driving chip includes a pin 24 and a pin 23, the gate of the field effect transistor is connected to the pin 24, the source is connected to the pin 23, and the drain is connected to the first output end.

[0018] Optionally, a diode is connected in series between the drain of the field effect tube and the first output terminal, the positive pole of the diode is connected to the drain of the field effect tube, the negative pole is connected to the first output terminal, the positive pole of the diode is connected to the ground terminal, a resistor and a capacitor are connected in series between the positive pole of the diode and the ground terminal, the negative pole of the diode is connected to the ground terminal, and a resistor is connected in series between the negative pole of the diode and the ground terminal.

[0019] Optionally, the backlight driving circuit further includes an inductor and a magnetic bead, one end of the magnetic bead is connected to the power supply end, and the other end is connected to the pin 28 of the driving chip, one end of the inductor is connected to the drain of the field effect tube, and the other end is grounded.

[0020] Optionally, the driving chip is provided with a first input pin to an Nth input pin and a first output pin to an Nth output pin, the first input pin to the Nth input pin are respectively connected to the input end, the first output pin to the Nth output pin are respectively connected to the second output end, and N is a positive integer greater than or equal to 1.

[0021] It can be known from the above technical scheme that the liquid crystal eye chart provided by the utility model includes a liquid crystal screen, a backlight driving circuit, a photosensitive sensor and a controller, wherein the liquid crystal screen includes a backlight source and a liquid crystal layer, the backlight source provides backlight to the liquid crystal layer, the backlight driving circuit is connected to the backlight source, and can control the voltage and current of the liquid crystal screen, the photosensitive sensor is arranged between the backlight source and the liquid crystal layer, and can measure the backlight intensity emitted by the backlight source and output a sensing signal accordingly, and the controller is respectively connected to the backlight driving circuit and the photosensitive sensor, and can obtain the sensing signal and output a control signal to the backlight driving circuit. The liquid crystal eye chart can output a control signal to the backlight driving circuit by the controller according to the acquired sensing signal, and control the voltage and current of the liquid crystal screen through the backlight driving circuit to control the backlight intensity emitted by the backlight source, thereby realizing automatic adjustment of the brightness of the liquid crystal screen, and can avoid the brightness of the liquid crystal eye chart affecting the accuracy of vision measurement. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the embodiments of the utility model or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the utility model. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0023] Figure 1 A schematic diagram of a liquid crystal eye chart provided by an embodiment of the utility model;

[0024] Figure 2 A structural diagram of a backlight driving circuit of a liquid crystal eye chart provided by an embodiment of the utility model;

[0025] Figure 3 A schematic diagram of a liquid crystal screen of a liquid crystal eye chart provided by an embodiment of the utility model;

[0026] Figure 4 for Figure 3 An enlarged schematic diagram of a portion A of the liquid crystal screen shown.

[0027] The reference numerals in the drawings of the specification include:

[0028] 100 - liquid crystal screen, 101 - backlight driving circuit, 102 - photosensor, 103 - sensing circuit, 104 - controller, 105 - first interface, 106 - second interface. DETAILED DESCRIPTION

[0029] In order to enable those skilled in the art to better understand the technical solutions in the present invention, the following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

[0030] This embodiment provides a liquid crystal eye chart, including:

[0031] A liquid crystal screen 100 for displaying sight marks, comprising a backlight source and a liquid crystal layer, wherein the backlight source is used to provide backlight to the liquid crystal layer;

[0032] A backlight driving circuit 101 connected to the backlight source and controlling the voltage and current of the liquid crystal screen 100;

[0033] A photosensor 102 disposed between the backlight source and the liquid crystal layer, for measuring the intensity of the backlight emitted by the backlight source and outputting a sensing signal accordingly;

[0034] A controller 104 is connected to the backlight driving circuit 101 and the photosensor 102 respectively, and is configured to obtain the sensing signal and output a control signal to the backlight driving circuit 101 .

[0035] The liquid crystal screen 100 includes a backlight source and a liquid crystal layer. The backlight source provides backlight to the liquid crystal layer. By controlling the electric field applied to the liquid crystal layer, the liquid crystal molecules in the liquid crystal layer twist with the applied electric field, so as to control the backlight to pass through the liquid crystal layer, so that the liquid crystal screen can realize the display function. The liquid crystal screen 100 displays a sight mark, thus becoming a liquid crystal eye chart. The backlight driving circuit 101 controls the voltage and current of the liquid crystal screen 100 to control the display of the liquid crystal screen 100. The sensing signal output by the light sensor 102 can reflect the intensity of the backlight emitted by the backlight source.

[0036] The liquid crystal eye chart of the present embodiment uses a photosensor to measure the intensity of backlight emitted by a backlight source and outputs a sensing signal accordingly. The controller can output a control signal to the backlight driving circuit based on the acquired sensing signal, and the voltage and current of the liquid crystal screen are controlled by the backlight driving circuit to control the intensity of backlight emitted by the backlight source, thereby automatically adjusting the brightness of the liquid crystal screen and preventing the brightness of the liquid crystal eye chart from affecting the accuracy of vision measurement.

[0037] In this embodiment, the type and structure of the photosensor 102 are not limited. In some embodiments, the photosensor 102 includes a sensor circuit 103, and the sensor circuit 103 is connected to the controller 104 through a first line and a second line, respectively. The first line is used for the sensor circuit 103 to transmit a high level / low level signal to the controller 104, and the second line is used for the sensor circuit 103 to transmit the sensing signal to the controller 104. For example, reference can be made to Figure 1 , Figure 1 A schematic diagram of a liquid crystal eye chart is provided for one embodiment. As shown in the figure, a photosensor 102 is provided on a liquid crystal screen 100. The photosensor 102 includes a sensing circuit 103. The sensing circuit 103 is connected to a controller 104 through a first line and a second line respectively. The first line transmits a digital signal, and the second line transmits an analog signal.

[0038] In some embodiments, the sensing circuit 103 compares the backlight intensity reflected by the sensing signal with a preset threshold value. If the backlight intensity reflected by the sensing signal exceeds the preset threshold value, a low-level signal is output, otherwise a high-level signal is output. The low-level signal or the high-level signal is transmitted to the controller 104 via the first line. The sensing circuit 103 can transmit the sensing signal to the controller 104 via the second line, and the sensing signal is an analog signal. When the controller 104 receives a low-level signal, it indicates that the brightness of the LCD screen 104 does not need to be adjusted. When the controller 104 receives a high-level signal, it indicates that the brightness of the LCD screen 100 is reduced and the brightness of the LCD screen 104 needs to be adjusted.

[0039] The controller 104 acquires the sensing signal and outputs the control signal to the backlight driving circuit 101, which may include: the controller 104 performs calculations according to the low-level signal / high-level signal output by the sensing circuit 103 and the sensing signal, and outputs the control signal to the backlight driving circuit 101. Before the controller 104 performs calculations according to the sensing signal output by the sensing circuit 103, it may first perform analog-to-digital conversion on the sensing signal to convert the sensing signal into a digital signal for further calculation to obtain a more accurate value of the backlight intensity. The control signal output by the controller 104 to the backlight driving circuit 101 may be a pulse width modulation (PWM) signal, and the duty cycle of the pulse width modulation signal may be adjusted to control the backlight intensity emitted by the backlight driving circuit 101. When the controller 104 receives a low-level signal, it indicates that the pulse width modulation signal does not need to be adjusted to adjust the backlight intensity emitted by the backlight source, and when the controller 104 receives a high-level signal, it indicates that the pulse width modulation signal needs to be adjusted to adjust the backlight intensity emitted by the backlight source.

[0040] In some embodiments, the voltage provided by the backlight driving circuit 101 to the LCD screen 100 remains unchanged, and the current provided to the LCD screen 100 changes. The backlight intensity emitted by the backlight source changes with the current. The voltage value of the voltage provided by the backlight driving circuit 101 to the LCD screen 100 remains constant. The intensity of the backlight emitted by the backlight source and the brightness of the LCD screen 100 can be controlled by changing the current provided by the backlight driving circuit 101 to the LCD screen 100.

[0041] The control signal output by the controller 104 to the backlight driving circuit 101 may be a pulse width modulation (PWM) signal. The controller 104 outputs the PWM signal, and adjusts the duty cycle of the PWM signal according to the calculation result of the low level signal / high level signal output by the sensor circuit 103 and the sensing signal, so that the backlight driving circuit 101 outputs a current with a corresponding current value, so that the backlight intensity emitted by the backlight source meets the requirements.

[0042] In some embodiments, the backlight driving circuit 101 includes a driving chip and a first output terminal, a second output terminal, an input terminal and an enable terminal respectively connected to the driving chip; the first output terminal and the second output terminal are respectively used to connect to the backlight source, the input terminal is used to input a pulse width modulation signal to the driving chip, and the enable terminal is used to enable the driving chip. When the enable terminal inputs a high-level signal to the driving chip, the first output terminal and the second output terminal output normally, and when the enable terminal inputs a low-level signal to the driving chip, the first output terminal and the second output terminal turn off the output.

[0043] The backlight driving circuit 101 also includes a field effect transistor, and the driving chip includes pins 24 and 23. The gate of the field effect transistor is connected to pin 24, the source is connected to pin 23, and the drain is connected to the first output terminal. Pin 24 is a GDRV pin, and pin 23 is an ISNS pin. The field effect transistor is used to control the opening and closing. When the field effect transistor is turned on, the output capacitor provides the current of the backlight source of the liquid crystal screen. When the field effect transistor is turned off, the magnetic energy in the form of a higher voltage is converted back into electricity to supply the backlight source of the liquid crystal screen.

[0044] In some embodiments, the backlight driving circuit 101 further includes an inductor and a magnetic bead, one end of the magnetic bead is connected to the power supply end, and the other end is connected to the pin 28 of the driving chip, one end of the inductor is connected to the drain of the field effect tube, and the other end is grounded. Pin 28 is a VIN pin. The magnetic bead is used as a filter. Since the magnetic bead has a very high resistivity and magnetic permeability, it is equivalent to a series circuit composed of a resistor and an inductor, which filters out ripple interference on the power supply end. The inductor plays a role of boosting, using magnetic energy for boost conversion.

[0045] In some embodiments, a diode is connected in series between the drain of the field effect tube and the first output terminal, the positive pole of the diode is connected to the drain of the field effect tube, the negative pole is connected to the first output terminal, the positive pole of the diode is connected to the ground terminal, and a resistor and a capacitor are connected in series between the positive pole of the diode and the ground terminal. The negative pole of the diode is connected to the ground terminal, and a resistor is connected in series between the negative pole of the diode and the ground terminal. The diode plays a role of rectification.

[0046] In some embodiments, the driving chip is provided with a first input pin to an Nth input pin and a first output pin to an Nth output pin, the first input pin to the Nth input pin are respectively connected to the input end, and the first output pin to the Nth output pin are respectively connected to the second output end, and N is a positive integer greater than or equal to 1.

[0047] For example, reference may be made to Figure 2 , Figure 2 A structural diagram of a backlight driving circuit of a liquid crystal eye chart provided in an embodiment. As shown in the figure, the backlight driving circuit 101 includes a driving chip U29 and a first output terminal LCD_LED_P, a second output terminal LCD_LED_N, an input terminal LCD_PWM and an enable terminal LED-PR_CTRL respectively connected to the driving chip U29.

[0048] The driver chip U29 includes:

[0049] Pin 1: UVLO, Pin 2: EN, Pin 3: PWM1, Pin 4: PWM2, Pin 5: PWM3, Pin 6: PWM4, Pin 7: PWM5, Pin 8: PWM6, Pin 9: FBP, Pin 10: ISET, Pin 11: IFBV, Pin 12: IFB1, Pin 13: IFB2, Pin 14: IFB3, Pin 15: IFB4, Pin 16: IFB5, Pin 17: IFB6, Pin 18: AGND, Pin 19: OVP, Pin 20: COMP, Pin 21: REF, Pin 22: PGND, Pin 23: ISNS, Pin 24: GDRV, Pin 25: VDD, Pin 26: FSW, Pin 27: FAULT, Pin 28: VIN, Pin 29: GND.

[0050] The working voltage of the driver chip U29 is 12V, and LCD_LED_P and LCD_LED_N are connected to the backlight interface of the LCD screen 100. LED-PR_CTRL enables the driver chip U29 to control the opening and closing of the backlight of the LCD screen 100. When LED-PR_CTRL inputs a high-level signal, LCD_LED_P and LCD_LED_N output normally; when LED-PR_CTRL inputs a low-level signal, LCD_LED_P and LCD_LED_N turn off the output. LCD_PWM inputs a PWM pulse width modulation signal to control the output current of the driver chip U29 and the backlight brightness of the LCD screen 100. The driver chip U29 is an LED driver chip, and the model can be TPS61196PWPRQ1.

[0051] The magnetic bead L33 is used as a filter. Since the magnetic bead has a high resistivity and magnetic permeability, it is equivalent to a series circuit composed of a resistor and an inductor, which can filter out the ripple interference on the 12V power supply. The model of the magnetic bead L33 can be BLM21PG220SN1. Capacitors C307, C308, C97, C86, C95, C305, and C306 respectively play the role of filtering and stabilizing voltage. Resistors RY23, RY27, and RY29 are used to control the input low voltage threshold. Resistors RY35 and RY34 are used to control the output high voltage threshold. Resistor RY37 is used to control the switching frequency, and resistor RY44 controls the six-way IFB1~IFB6 output current. The inductor L32 performs a voltage boosting function, using magnetic energy for voltage boosting conversion, and is turned on and off by the field effect tube Q1. When the field effect tube Q1 is turned on, the output capacitor provides the backlight current of the LCD screen. When the field effect tube Q1 is turned off, the magnetic energy in the form of a higher voltage is converted back into electricity to supply the backlight source of the LCD screen 100. The Schottky diode D2 performs a rectifier function.

[0052] In the backlight driving circuit 101, six pulse width modulation signals PWM are input, the carrier frequency is set to 20kHz, and six outputs are output, each outputting 60mA, and the total output is 360mA.

[0053] Input low voltage threshold = 1.229 × (RY23 + RY27 + RY29) / RY29 = 10V.

[0054] Output high voltage threshold = RY35×3.02 / RY34+3.02=71V.

[0055] fsw=4000 / RY37=200kHz. Iset=3992×1.229 / RY44=60mA.

[0056] Inductor current ILp=0.84+0.38=1.32A.

[0057] Schottky diode I>1.32A, Vrb>51.5V; field effect transistor Id>1.32A, V>51.5V.

[0058] Vripple=0.01V@100uF+Vripple(esr). Current protection current I=0.4 / 0.1=4A.

[0059] The brightness value of the LCD screen 100 is detected by the light sensor 102, the PWM duty cycle is fine-tuned (adjustable from 0 to 100%), and the corresponding current value is output (adjustable from 0 to 360 mA) to keep the backlight brightness constant.

[0060] In this embodiment, the structure of the controller 104 is not limited. The controller 104 may be, but is not limited to, a microcontroller unit (MCU).

[0061] In this embodiment, the specific structure of the liquid crystal screen 100 is not limited, and can be set according to display requirements in actual applications. Figure 3 and Figure 4 , Figure 3 is a schematic diagram of a liquid crystal screen of a liquid crystal eye chart provided by an embodiment, Figure 4 for Figure 3 The enlarged schematic diagram of a part A of the liquid crystal screen is shown. In some embodiments, the liquid crystal screen 100 may be provided with a first interface 105 and a second interface 106. The first interface 105 is used to connect the backlight source, and the backlight source is connected to the controller 104 through the first interface 105. The second interface 106 is used to connect the photosensitive sensor 102, and the photosensitive sensor 102 is connected to the controller 104 through the second interface 106. As shown in the figure, the first interface 105 and the second interface 106 are arranged side by side, so that the wiring is convenient when connecting to the controller 104.

[0062] The liquid crystal screen 100 includes a backlight source and a liquid crystal layer. In some embodiments, a light leakage hole is provided on the liquid crystal screen 100 and corresponds to the backlight source and the liquid crystal layer. The light sensor 102 is provided corresponding to the light leakage hole or the light sensor 102 extends into the light leakage hole. The light sensor 102 is used to measure the intensity of light transmitted from the light leakage hole. Such a configuration makes the liquid crystal eye chart compact.

[0063] The LCD eye chart can automatically adjust the brightness to keep the brightness of the LCD screen 100 constant, for example, the brightness is maintained at 250cd / ㎡±10%, thereby solving the problem of the LCD eye chart's brightness decaying over time and improving the reliability of the LCD eye chart's backlight brightness to avoid affecting the accuracy of vision measurement.

[0064] The above is a detailed introduction to a liquid crystal eye chart provided by the utility model. This article uses specific examples to illustrate the principle and implementation method of the utility model. The description of the above embodiment is only used to help understand the method and core idea of ​​the utility model. It should be pointed out that for ordinary technicians in this technical field, without departing from the principle of the utility model, the utility model can also be improved and modified, and these improvements and modifications also fall within the scope of protection of the claims of the utility model.

Claims

1. A liquid crystal eye chart, characterized in that: include: A liquid crystal screen for displaying sight marks, comprising a backlight source and a liquid crystal layer, wherein the backlight source is used to provide backlight to the liquid crystal layer; A backlight driving circuit connected to the backlight source and controlling the voltage and current of the liquid crystal screen; A photosensor disposed between the backlight source and the liquid crystal layer, for measuring the intensity of backlight emitted by the backlight source and outputting a sensing signal accordingly; A controller is connected to the backlight driving circuit and the photosensor respectively, and acquires the sensing signal and outputs a control signal to the backlight driving circuit.

2. The liquid crystal eye chart according to claim 1, characterized in that: The LCD screen is provided with a first interface and a second interface, the first interface is used to connect the backlight source, and the backlight source is connected to the controller through the first interface, and the second interface is used to connect the photosensor, and the photosensor is connected to the controller through the second interface.

3. The liquid crystal eye chart according to claim 1, characterized in that: A light leakage hole is arranged on the liquid crystal screen and corresponds to the backlight source and the liquid crystal layer. The photosensor is arranged corresponding to the light leakage hole or extends into the light leakage hole. The photosensor is used to measure the intensity of light transmitted from the light leakage hole.

4. The liquid crystal eye chart according to claim 1, characterized in that: The photosensor includes a sensing circuit, which is connected to the controller via a first line and a second line respectively. The first line is used for the sensing circuit to transmit a high level / low level signal to the controller, and the second line is used for the sensing circuit to transmit the sensing signal to the controller.

5. The liquid crystal eye chart according to claim 1, characterized in that: The voltage magnitude provided by the backlight driving circuit to the liquid crystal screen remains unchanged, while the current magnitude provided to the liquid crystal screen changes, and the backlight intensity emitted by the backlight source changes with the current magnitude.

6. The liquid crystal eye chart according to claim 1, characterized in that: The backlight driving circuit comprises a driving chip and a first output terminal, a second output terminal, an input terminal and an enable terminal respectively connected to the driving chip; The first output terminal and the second output terminal are respectively used to connect to the backlight source, the input terminal is used to input a pulse width modulation signal to the driver chip, and the enable terminal is used to enable the driver chip. When the enable terminal inputs a high-level signal to the driver chip, the first output terminal and the second output terminal output normally, and when the enable terminal inputs a low-level signal to the driver chip, the first output terminal and the second output terminal turn off the output.

7. The liquid crystal eye chart according to claim 6, characterized in that: The backlight driving circuit further includes a field effect transistor, the driving chip includes a pin 24 and a pin 23, the gate of the field effect transistor is connected to the pin 24, the source is connected to the pin 23, and the drain is connected to the first output end.

8. The liquid crystal eye chart according to claim 7, characterized in that: A diode is connected in series between the drain of the field effect tube and the first output terminal, the positive pole of the diode is connected to the drain of the field effect tube, and the negative pole is connected to the first output terminal, the positive pole of the diode is connected to the ground terminal, a resistor and a capacitor are connected in series between the positive pole of the diode and the ground terminal, the negative pole of the diode is connected to the ground terminal, and a resistor is connected in series between the negative pole of the diode and the ground terminal.

9. The liquid crystal eye chart according to claim 7, characterized in that: The backlight driving circuit also includes an inductor and a magnetic bead, one end of the magnetic bead is connected to the power supply end, and the other end is connected to the pin 28 of the driving chip. One end of the inductor is connected to the drain of the field effect tube, and the other end is grounded.

10. The liquid crystal eye chart according to claim 6, characterized in that: The driving chip is provided with a first input pin to an Nth input pin and a first output pin to an Nth output pin, the first input pin to the Nth input pin are respectively connected to the input end, the first output pin to the Nth output pin are respectively connected to the second output end, and N is a positive integer greater than or equal to 1.

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