LCD (liquid crystal display) capable of automatically adjusting brightness according to light

Abstract

The utility model discloses an LCD (liquid crystal display) capable of automatically adjusting brightness according to light. Comprising a liquid crystal panel used for displaying images and video information, a driving circuit used for processing and controlling display signals of the liquid crystal panel, and a backlight source used for providing uniform light to enable the liquid crystal panel to display clear images. The light sensing module is used for sensing external environment light; the backlight control module is used for controlling backlight brightness through a PWM (Pulse Width Modulation) signal; through cooperation of the liquid crystal panel, the driving circuit, the backlight source, the photosensitive module and the backlight control module, the photosensitive module senses external environment light in real time and transmits sensed light signals to the backlight control module, so that the backlight control module controls backlight brightness by adjusting PWM signals, the brightness of the liquid crystal panel is adjusted, and the brightness of the liquid crystal panel is adjusted. The purpose of automatically adjusting the brightness of the liquid crystal panel according to the light is achieved.

Description

Technical Field

[0001] This utility model relates to the field of LCD liquid crystal display technology, specifically to an LCD liquid crystal display that automatically adjusts its brightness according to light. Background Technology

[0002] Currently, LCD screens on the market are mainly composed of polarizers, liquid crystal layers, electrodes, and backlight modules. The backlight module typically uses light sources such as LEDs (light-emitting diodes) or CCFLs (cold cathode fluorescent lamps) to provide enough light to penetrate the liquid crystal layer so that the image can be clearly seen.

[0003] For example, patent application number 201820787190.X discloses a liquid crystal display screen, including: a frame, the frame being a four-sided frame structure composed of four sets of mounting plates, wherein the mounting plates have several mounting slots inside, and the mounting slots house a protective screen, a display module, a heating and defogging film, a backlight, a control circuit board, and a back cover; the protective screen is fixed to the front side of the frame, the display module is located on the rear side of the protective screen, the heating and defogging film is located on the rear side of the display module, the backlight is located on the rear side of the heating and defogging film, the control circuit board is located on the rear side of the backlight, and the back cover is located on the rear side of the control circuit board, the back cover being fastened to the frame; the back cover has wiring holes for connecting to the control circuit board; and an inner liner is provided inside the mounting slots. This utility model improves the display effect of the display screen in low-temperature environments by incorporating a heating and defogging film.

[0004] However, since LCD screens rely on backlights for illumination, and the brightness of backlights is usually fixed or can only be adjusted through a limited number of brightness levels, the brightness of the backlight cannot be adjusted automatically and in real time when the ambient light changes. Therefore, we need to propose an LCD screen that automatically adjusts its brightness according to the ambient light to solve the above-mentioned problems, so that it can automatically adjust its brightness when the ambient light changes. Summary of the Invention

[0005] The purpose of this invention is to provide an LCD screen that automatically adjusts its brightness according to changes in ambient light, thereby solving the problems mentioned in the background art.

[0006] To achieve the above objectives, this utility model provides the following technical solution: an LCD liquid crystal display screen that automatically adjusts its brightness according to light, comprising a liquid crystal panel for displaying images and video information, a driving circuit for processing and controlling the display signals of the liquid crystal panel, a backlight for providing uniform light so that the liquid crystal panel can display clear images, a photosensitive module for sensing ambient light, and a backlight control module for controlling the backlight brightness through a PWM signal. The backlight control module is electrically connected to the backlight and the photosensitive module, respectively. The backlight is electrically connected to the driving circuit, and the driving circuit is electrically connected to the liquid crystal panel.

[0007] The backlight control module includes a PWM signal adjustment unit and a control unit, with the two terminals of the PWM signal adjustment unit connected to the backlight and the control unit, respectively.

[0008] Preferably, the photosensitive module includes a light intensity sensor chip U4 and a connection terminal P4 connected to the light intensity sensor chip U4. A capacitor to ground is connected to pin 2 of the light intensity sensor chip U4. A capacitor C10 is connected between pins 1 and 3 of the light intensity sensor chip U4. Pins 6 and 4 of the light intensity sensor chip U4 are both connected to the connection terminal P4. A capacitor to ground C11 and a resistor R10 for connecting to VCC are connected in parallel to pin 5 of the light intensity sensor chip U4. A resistor R12 for connecting to VCC is also connected to pin 4 of the light intensity sensor chip U4. A resistor R11 for connecting to VCC is also connected to pin 6 of the light intensity sensor chip U4.

[0009] Preferably, the PWM signal adjustment unit includes a silicon controlled rectifier (SCR) Q2 and an optocoupler U22. One sensing terminal of the optocoupler U2 is connected to a resistor R62 for connecting to a 5V voltage. One end of the SCR Q2 is connected to one control terminal of the optocoupler U22. The other control terminal of the optocoupler U22 is connected to a resistor R72. One end of the resistor R72 is connected to the other end of the SCR Q2. A resistor R52 is connected to the connection terminal of the SCR Q2 and the optocoupler U22. A resistor R92 and a capacitor C52 are connected in series between the two control terminals of the optocoupler U22. The other end of the capacitor C52 is connected to the other end of the resistor R52. A PWM interface for connecting to a backlight is provided on the connection terminal of the capacitor C52 and the resistor R52.

[0010] Preferably, the control unit includes a programmable control chip U33, pin 11 of the control chip is connected to another sensing terminal of the optocoupler U22, pin 6 of the control chip U33 is connected to the connection terminal of resistor R92 and silicon controlled rectifier Q2, and pin 10 of the control chip U33 is grounded.

[0011] Preferably, the backlight includes a driver chip U8. A resistor R21 is connected between pins 1 and 2 of the driver chip U8, and a ground resistor R31 is connected to the connection point between pin 1 of the driver chip U8 and resistor R21. A resistor R16 for receiving PWM signals is connected to pin 3 of the driver chip U8. A ground capacitor C1 is connected to pin 4 of the driver chip U8. A resistor R17 and a ground capacitor C20 are connected in series between the ground capacitor C1 and the connection point between the ground capacitor C1 and the driver chip U8. A resistor R17 and a ground capacitor C20 are connected to pin 6 of the driver chip U8. A MOSFET Q1 is connected. Diodes D1 and D2, arranged in parallel, and inductor L1 and capacitor C12, arranged in series, are connected to the source of the MOSFET Q1. Resistor R25 is connected to the drain of the MOSFET Q1. Capacitor C5 is connected to pin 9 of the driver chip U8. The other end of resistor R25 is connected to pins 10 and 8 of the driver chip U8 and the other end of capacitor C5. Capacitors C17 and C18, arranged in association, are also connected to pin 10 of the driver chip U8.

[0012] Preferably, the liquid crystal panel is a TFT display screen, with a ground resistor R3 connected to pin 1 of the TFT display screen, a resistor R6 connected to pin 2 of the TFT display screen, a resistor R5 connected to pin 3 of the TFT display screen, and a resistor R1 connected to pin 30 of the TFT display screen. The other ends of resistors R6, R5, and R1 are all connected to a 5V power supply.

[0013] Preferably, the driving circuit includes an ADC chip U2, an ADC chip U1, and a driving chip P1, which are respectively connected to the TFT display screen. A resistor R4 is connected between pins 9 and 10 of the ADC chip U2, a resistor R2 is connected between pins 14 and 15 of the ADC chip U1, and a connector head is connected to the ADC chip U1.

[0014] Compared with the prior art, the beneficial effects of this utility model are:

[0015] This invention utilizes the cooperation of a liquid crystal panel, a driving circuit, a backlight, a photosensitive module, and a backlight control module. The photosensitive module senses ambient light in real time and transmits the sensed light signal to the backlight control module. The backlight control module then adjusts the PWM signal to control the backlight brightness, thereby regulating the brightness of the liquid crystal panel and achieving the goal of automatically adjusting the brightness of the liquid crystal panel according to the ambient light. Attached Figure Description

[0016] Figure 1 This is a system block diagram of the present invention;

[0017] Figure 2 This is the circuit diagram of the photosensitive module of this utility model;

[0018] Figure 3 This is the circuit diagram of the PWM signal conditioning unit of this utility model;

[0019] Figure 4 This is the circuit diagram of the control unit of this utility model;

[0020] Figure 5 This is the circuit diagram of the liquid crystal panel of this utility model;

[0021] Figure 6 This is a circuit diagram of the driving circuit of this utility model;

[0022] Figure 7 This is the circuit diagram of the backlight of this utility model. Detailed Implementation

[0023] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0024] Please see Figure 1-7 This utility model provides a technical solution: an LCD liquid crystal display screen that automatically adjusts its brightness according to light, comprising a liquid crystal panel for displaying images and video information, a driving circuit for processing and controlling the display signals of the liquid crystal panel, a backlight for providing uniform light so that the liquid crystal panel can display clear images, a photosensitive module for sensing ambient light, and a backlight control module for controlling the backlight brightness through a PWM signal. The backlight control module is electrically connected to the backlight and the photosensitive module, respectively. The backlight is electrically connected to the driving circuit, and the driving circuit is electrically connected to the liquid crystal panel.

[0025] The photosensitive module includes a light intensity sensor chip U4 and a connection terminal P4 connected to the light intensity sensor chip U4. A capacitor to ground is connected to pin 2 of the light intensity sensor chip U4. A capacitor C10 is connected between pins 1 and 3 of the light intensity sensor chip U4. Pins 6 and 4 of the light intensity sensor chip U4 are both connected to the connection terminal P4. A capacitor C11 to ground and a resistor R10 for connecting to VCC are connected in parallel to pin 5 of the light intensity sensor chip U4. A resistor R12 for connecting to VCC is also connected to pin 4 of the light intensity sensor chip U4. A resistor R11 for connecting to VCC is also connected to pin 6 of the light intensity sensor chip U4. The light intensity sensor chip U4 is an electronic component that can sense the intensity of light. When external light shines on the light intensity sensor chip U4, the chip will adjust its output signal according to the intensity of the light. The capacitor C10 connected between pins 1 and 3 may be used for filtering or decoupling to stabilize the chip's operating voltage and reduce noise interference.

[0026] The backlight control module includes a PWM signal adjustment unit and a control unit, wherein the two terminals of the PWM signal adjustment unit are respectively connected to the backlight and the control unit;

[0027] The PWM signal adjustment unit includes a silicon controlled rectifier (SCR) Q2 and an optocoupler U22. One sensing terminal of the optocoupler U2 is connected to a resistor R62 for connecting to a 5V voltage. One end of the SCR Q2 is connected to one control terminal of the optocoupler U22. The other control terminal of the optocoupler U22 is connected to a resistor R72. One end of the resistor R72 is connected to the other end of the SCR Q2. A resistor R52 is connected to the connection terminal of the SCR Q2 and the optocoupler U22. A resistor R92 and a capacitor C52 are connected in series between the two control terminals of the optocoupler U22. The other end of the capacitor C52 is connected to the other end of the resistor R52. A PWM interface for connecting to a backlight is provided on the connection terminal of the capacitor C52 and the resistor R52.

[0028] The control unit includes a programmable control chip U33. Pin 11 of the control chip is connected to the other sensing terminal of the optocoupler U22. Pin 6 of the control chip U33 is connected to the connection terminal of resistor R92 and silicon controlled rectifier Q2. Pin 10 of the control chip U33 is grounded. The control chip U33 generates a PWM signal as needed and transmits it to the silicon controlled rectifier Q2 through the optocoupler U22. The silicon controlled rectifier Q2 turns on and off according to the duty cycle of the PWM signal, thereby controlling the current through the backlight. Changes in current cause changes in the brightness of the backlight. The higher the duty cycle of the PWM signal, the longer the silicon controlled rectifier Q2 is on, the greater the current through the backlight, and the higher the brightness; conversely, the lower the duty cycle, the lower the brightness.

[0029] The backlight includes a driver chip U8. A resistor R21 is connected between pins 1 and 2 of the driver chip U8. A ground resistor R31 is connected to the connection between pin 1 of the driver chip U8 and resistor R21. A resistor R16 for receiving PWM signals is connected to pin 3 of the driver chip U8. A ground capacitor C1 is connected to pin 4 of the driver chip U8. A resistor R17 and a ground capacitor C20 are connected in series between the ground capacitor C1 and the connection between the ground capacitor C1 and the driver chip U8. A MOSFET Q1 is connected to pin 6 of the driver chip U8. Diodes D1 and D2, arranged in parallel, and an inductor L1 and a ground capacitor C12, arranged in series, are connected to the source of the MOSFET Q1. A resistor R25 is connected to the drain of the MOSFET Q1. A capacitor C5 is connected to pin 9 of the driver chip U8. The other end of the resistor R25 is connected to pins 10 and 8 of the driver chip U8 and the other end of the capacitor C5. Pin 10 of chip U8 is connected to capacitors C17 and C18, which are arranged in an associated configuration. Pin 3 of driver chip U8 receives PWM signals through resistor R16. The duty cycle of the PWM signal determines the amount of output energy, thereby controlling the average current of the backlight LED and thus the brightness of the screen backlight. A high duty cycle results in a brighter LED, while a low duty cycle results in a dimmer LED. Driver chip U8 receives the PWM signal and controls the switching state of MOSFET Q1 based on the signal, thereby achieving precise control of the backlight LED. Under the control of driver chip U8, MOSFET Q1 switches between the variable resistance region and the pinch-off region. When MOSFET Q1 is on, the backlight LED receives current and emits light; when MOSFET Q1 is off, the current to the backlight LED is cut off, and it stops emitting light. Inductor L1 and capacitor C12 form a filter circuit to smooth the current fluctuations generated when MOSFET Q1 is switched, ensuring a stable current supply to the backlight LED.

[0030] The LCD panel is configured as a TFT display screen. A resistor R3 is connected to ground on pin 1 of the TFT display screen, a resistor R6 is connected to pin 2 of the TFT display screen, a resistor R5 is connected to pin 3 of the TFT display screen, and a resistor R1 is connected to pin 30 of the TFT display screen. The other ends of resistors R6, R5, and R1 are all connected to a 5V power supply.

[0031] The driving circuit includes ADC chip U2, ADC chip U1, and driver chip P1, which are respectively connected to the TFT display screen. A resistor R4 is connected between pins 9 and 10 of ADC chip U2, and a resistor R2 is connected between pins 14 and 15 of ADC chip U1. A connector head is connected to ADC chip U1, and external analog signals are input to ADC chip U1 through the connector head. ADC chip U1 converts these analog signals into digital signals. During the conversion process, resistor R2 acts as a voltage divider, current limiter, or provides a reference potential. ADC chip U2 is responsible for processing analog signals from other sources or for other purposes and converting them into digital signals. The converted digital signals are sent to driver chip P1. Driver chip P1 receives the digital signals from ADC chip U1 and ADC chip U2 and generates signals to control the pixels of the TFT display screen based on these signals. The control signals are transmitted to each pixel through the internal circuit of the TFT display screen, thereby controlling the arrangement of liquid crystal molecules and the polarization of light, and ultimately realizing the display of the image.

[0032] By coordinating the LCD panel, driving circuit, backlight, photosensitive module, and backlight control module, the photosensitive module senses ambient light in real time and transmits the sensed light signal to the backlight control module. The backlight control module then adjusts the PWM signal to control the backlight brightness, thereby regulating the brightness of the LCD panel and achieving the goal of automatically adjusting the LCD panel brightness according to the ambient light.

[0033] Although embodiments of the present invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the present invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. An LCD liquid crystal display screen that automatically adjusts its brightness according to light, characterized in that: The device includes a liquid crystal panel for displaying images and video information, a driving circuit for processing and controlling the display signals of the liquid crystal panel, a backlight for providing uniform light so that the liquid crystal panel can display clear images, a photosensitive module for sensing ambient light, and a backlight control module for controlling the backlight brightness via a PWM signal. The backlight control module is electrically connected to the backlight and the photosensitive module, respectively. The backlight is electrically connected to the driving circuit, and the driving circuit is electrically connected to the liquid crystal panel. The backlight control module includes a PWM signal adjustment unit and a control unit, wherein the two terminals of the PWM signal adjustment unit are respectively connected to the backlight and the control unit; The PWM signal adjustment unit includes a silicon controlled rectifier (SCR) Q2 and an optocoupler U22. One sensing terminal of the optocoupler U2 is connected to a resistor R62 for connecting to a 5V voltage. One end of the SCR Q2 is connected to one control terminal of the optocoupler U22. The other control terminal of the optocoupler U22 is connected to a resistor R72. One end of the resistor R72 is connected to the other end of the SCR Q2. A resistor R52 is connected to the connection terminal of the SCR Q2 and the optocoupler U22. A resistor R92 and a capacitor C52 are connected in series between the two control terminals of the optocoupler U22. The other end of the capacitor C52 is connected to the other end of the resistor R52. A PWM interface for connecting to a backlight is provided on the connection terminal of the capacitor C52 and the resistor R52. The control unit includes a programmable control chip U33. Pin 11 of the control chip is connected to another sensing terminal of the optocoupler U22. Pin 6 of the control chip U33 is connected to the connection terminal of the resistor R92 and the silicon controlled rectifier Q2. Pin 10 of the control chip U33 is grounded.

2. The LCD liquid crystal display screen with self-adjusting brightness according to light as described in claim 1, characterized in that: The photosensitive module includes a light intensity sensor chip U4 and a connection terminal P4 connected to the light intensity sensor chip U4. A capacitor to ground is connected to pin 2 of the light intensity sensor chip U4. A capacitor C10 is connected between pins 1 and 3 of the light intensity sensor chip U4. Pins 6 and 4 of the light intensity sensor chip U4 are both connected to the connection terminal P4. A capacitor to ground C11 and a resistor R10 for connecting to VCC are connected in parallel to pin 5 of the light intensity sensor chip U4. A resistor R12 for connecting to VCC is also connected to pin 4 of the light intensity sensor chip U4. A resistor R11 for connecting to VCC is also connected to pin 6 of the light intensity sensor chip U4.

3. The LCD liquid crystal display screen with self-adjusting brightness according to light as described in claim 1, characterized in that: The backlight includes a driver chip U8. A resistor R21 is connected between pins 1 and 2 of the driver chip U8, and a ground resistor R31 is connected to the connection point between pin 1 of the driver chip U8 and resistor R21. A resistor R16 for receiving PWM signals is connected to pin 3 of the driver chip U8. A ground capacitor C1 is connected to pin 4 of the driver chip U8. A resistor R17 and a ground capacitor C20 are connected in series between the ground capacitor C1 and the connection point between the ground capacitor C1 and the driver chip U8. A resistor R17 and a ground capacitor C20 are connected to pin 6 of the driver chip U8. There is a MOSFET Q1. Diodes D1 and D2 are connected in parallel to the source of MOSFET Q1, as are inductor L1 and capacitor C12 connected in series. Resistor R25 is connected to the drain of MOSFET Q1. Capacitor C5 is connected to pin 9 of driver chip U8. The other end of resistor R25 is connected to pins 10 and 8 of driver chip U8 and the other end of capacitor C5. Capacitors C17 and C18 are also connected in association to pin 10 of driver chip U8.

4. The LCD liquid crystal display screen that self-adjusts its brightness according to light, as described in claim 1, is characterized in that: The LCD panel is configured as a TFT display screen. A resistor R3 is connected to ground on pin 1 of the TFT display screen, a resistor R6 is connected to pin 2 of the TFT display screen, a resistor R5 is connected to pin 3 of the TFT display screen, and a resistor R1 is connected to pin 30 of the TFT display screen. The other ends of resistors R6, R5, and R1 are all connected to a 5V power supply.

5. An LCD liquid crystal display screen that self-adjusts its brightness according to light, as described in claim 4, characterized in that: The driving circuit includes an ADC chip U2, an ADC chip U1, and a driving chip P1, which are respectively connected to the TFT display screen. A resistor R4 is connected between pins 9 and 10 of the ADC chip U2, and a resistor R2 is connected between pins 14 and 15 of the ADC chip U1. A connector head is connected to the ADC chip U1.

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