WO2015010383A1

WO2015010383A1 - Liquid crystal display

Info

Publication number: WO2015010383A1
Application number: PCT/CN2013/086241
Authority: WO
Inventors: 段亚锋; 金亨奎; 孙伟; 邓立广; 刘英明
Original assignee: 北京京东方光电科技有限公司
Priority date: 2013-07-26
Filing date: 2013-10-30
Publication date: 2015-01-29
Also published as: CN103412426A; CN103412426B

Abstract

A liquid crystal display, comprising: a temperature sensor (12), a temperature control unit (10), and a heating circuit (13); the temperature sensor (12) is used to transmit the temperature of a liquid crystal display (14) to the temperature control unit (10); the temperature control unit (10) is used to determine, according to the temperature of the liquid crystal display (14) collected by the temperature sensor (12), whether to control the heating circuit (13) to heat the liquid crystal display (14); and the heating circuit (13) is used to heat the liquid crystal display (14) under the control of the temperature control unit (10). The present invention widens the low-temperature working range of the liquid crystal display (14), and ensures normal operation and quick response thereof in a low-temperature environment.

Description

Liquid crystal display technology

The present invention relates to the field of display technologies, and in particular, to a liquid crystal display. Background technique

When the ambient temperature is lower than o°c, the liquid crystal material becomes viscous. When the temperature is lower, the liquid crystal material even “crystallizes”, which causes the liquid crystal display to change color when it starts working at low temperature. The brightness is low, and the phenomenon of "tailing" occurs. When it is serious, the graphic and image display cannot be seen at all, and some special environmental conditions cannot be met.

In order to make the liquid crystal display screen operate normally at a low temperature, the prior art has proposed heating in the liquid crystal of the liquid crystal display panel, but it often causes difficulty in liquid crystal outflow or reduction. In addition, there is another way in the prior art: to increase the brightness of the liquid crystal display, that is, to increase the backlight tube, and to develop a special high-pressure strip at a low temperature.

( -40 ° C ) to brighten the backlight tube, wherein the high voltage strip can generate a starting voltage of 2000V~3200V, and the huge heat generated by the backlight tube causes the liquid crystal to heat up. This way, the two methods can solve the low temperature of the liquid crystal. Work problems, and solve the problem of visibility in the sun, this method is called: brightening method.

However, there are many quality hazards in the above methods: many accessories are added, which reduces the reliability; assembly is more troublesome to produce, it is easy to cause defective products, and the defective rate is higher; the ability of the device to resist impact and vibration is reduced; the aging speed Extremely fast, with an increase in acceleration, especially in the way of brightening, the life is only 1/10 of the normal life.

In addition, some foreign companies have developed wide-temperature liquid crystal materials with higher clearing points, lower viscosity coefficients, and lower internal voltage voltages with uniform threshold characteristics over a wider temperature range. However, due to their high price, they are not easy to popularize and apply.

In addition, the new low-temperature reinforced liquid crystal display has achieved a breakthrough in technology, and the micro-power heating problem of the liquid crystal display can be solved without opening the inside of the liquid crystal display module assembly and installing the heater. The low temperature display of the liquid crystal display can be realized, but when the ambient temperature changes, the internal temperature of the liquid crystal display cannot be controlled, and the range of use thereof is limited. Summary of the invention

In view of the deficiencies of the prior art, embodiments of the present invention provide a liquid crystal display for widening the low temperature working range of the liquid crystal display to ensure that it can work normally in a low temperature environment and has a fast response speed. A liquid crystal display according to an embodiment of the present invention, the liquid crystal display comprising: a temperature control unit, a temperature sensor and a heating circuit, the temperature sensor is configured to transmit the temperature of the liquid crystal display to the temperature control unit; and the temperature control unit is configured to The temperature of the liquid crystal display screen collected by the sensor controls the heating circuit to work, that is, the temperature control unit controls whether the heating circuit is turned on according to the temperature value of the liquid crystal display screen collected by the temperature sensor; the heating circuit is used for liquid crystal display according to the control of the temperature control unit Spread the heat.

The liquid crystal display of the embodiment of the invention can realize the operation of the liquid crystal display in a very low temperature range, and can automatically control the temperature in the liquid crystal display when the external environment changes, without manual control, and the environment adaptability is strong.

Optionally, the heating circuit comprises: a switching device, a heater and a power source, wherein the switching device is controlled by the temperature control unit, and in the case of being turned off, the power source supplies power to the heater, and the heater starts to heat up.

Thus, when the heater starts heating, the low temperature operating range of the liquid crystal display can be widened. Optionally, the heating circuit further includes a fuse between the power supply access point and the heater. Thus, the fuse is used for protection of overcurrent, and it is possible to effectively prevent the device in the heating circuit from being burned out.

Optionally, the switching device is a first transistor, and the heating circuit further includes a first resistor connected between the power supply access point and the gate of the first transistor, and the gate of the first transistor The temperature control unit is connected, and the other two stages are connected to the heater and grounding point respectively.

In this way, the first transistor connected to the temperature control unit of the gate functions as a switch, and the transistor is used as a switching device to facilitate the implementation of the single tube, wherein the first resistor is used as a shunt resistor to protect the current from being excessively burned. Bad devices, but also easy to install.

Optionally, the heating circuit further includes a first capacitor and a second resistor, the first capacitor and the second resistor being respectively connected between the first transistor gate and the ground point.

Thus, the RC circuit composed of the first capacitor and the second resistor increases the time during which the switching signal of the first transistor is turned on and off, and the impact of the heating circuit on the power supply circuit is alleviated.

Optionally, the heating circuit further includes a second transistor having a gate connected to the temperature control unit, and the other two stages are respectively connected to the ground point and the gate of the first transistor.

Thus, the second transistor functions the same as the first transistor, and is a switching device in the heating circuit, which is easy to implement in the design of the heating circuit.

Optionally, the heating circuit further includes a second capacitor and a third resistor, wherein the third resistor is connected to Between the temperature control unit and the gate of the second transistor, the second capacitor is connected between the gate of the second transistor and the ground.

Thus, an RC circuit composed of a third resistor connected between the temperature control unit and the gate of the second transistor and a second capacitor connected between the gate of the second transistor and the ground point can function for the entire heating circuit Filtering, voltage regulation.

Optionally, the heater is located inside the liquid crystal display.

In this way, the heater is located inside the liquid crystal display, which is easy to control, low in cost and easy to handle, and does not require disassembly of the liquid crystal display, thereby improving the reliability of the display.

Optionally, the heating circuit comprises a plurality of heaters, wherein the plurality of heaters are connected in series or in parallel, respectively, at different positions inside the liquid crystal display.

In this way, the heaters located at different positions inside the liquid crystal display can uniformly heat the liquid crystal display.

Optionally, the liquid crystal display comprises a plurality of temperature sensors respectively connected to the temperature control unit, at different positions inside the liquid crystal display.

In this way, temperature sensors located at different locations inside the LCD display can capture more accurate temperature values. DRAWINGS

1 is a schematic diagram of a liquid crystal display according to Embodiment 1 of the present invention;

2 is a schematic diagram of another liquid crystal display according to Embodiment 2 of the present invention. detailed description

The embodiment of the invention provides a liquid crystal display for widening the low temperature working range of the liquid crystal display to ensure that it can work normally in a low temperature environment and has a fast response speed.

A detailed description of the technical solutions provided in the embodiments of the present invention is given below.

Embodiment 1:

As shown in FIG. 1, the embodiment provides a liquid crystal display, which includes: a temperature control unit 10, a temperature sensor 12, and a heating circuit 13, and the temperature sensor 12 is used to transmit the temperature of the liquid crystal display 14 to the temperature control. The temperature control unit 10 is configured to determine whether to control the heating circuit 13 to heat the liquid crystal display 14 according to the temperature of the liquid crystal display 14 collected by the temperature sensor 12; and the heating circuit 13 for controlling the temperature control unit 10, The liquid crystal display 14 is heated. Optionally, the heating circuit 13 comprises: a switching device 0, a heater L and a power source 11 , wherein the switching device Q is controlled by the temperature control unit 10, and in the case of being turned off, the power source 11 supplies power to the heater L, heating The device L starts heating.

The switching device Q can be a transistor, the gate of the transistor Q is connected to the temperature control unit 10, and the other two stages are respectively connected to the heater L and the ground point. One end of the heater L is connected to the power source 11 and the other end is connected to the transistor Q. .

Optionally, the heater L is located inside the liquid crystal display 14.

Optionally, the heating circuit 13 includes a plurality of heaters L respectively located at different positions inside the liquid crystal display panel 14, wherein the plurality of heaters may be connected in series or in parallel.

Optionally, the liquid crystal display comprises a plurality of temperature sensors 12 respectively connected to the temperature control unit 10, which are respectively located at different positions inside the liquid crystal display 14.

Embodiment 2:

As shown in FIG. 2, a liquid crystal display according to another embodiment of the present invention includes: a temperature control unit 20, a temperature sensor 22, and a heating circuit 23 for transmitting the temperature of the liquid crystal display 24 to The temperature control unit 20 is configured to determine whether to control the heating circuit 23 to heat the liquid crystal display 24 according to the temperature of the liquid crystal display 24 collected by the temperature sensor 22; and the heating circuit 23 for controlling according to the temperature control unit 20 , for the LCD screen 24 heat.

Illustratively, the temperature control unit 20 in the embodiment of the present invention is a single chip microcomputer.

Optionally, the heating circuit 23 may include: a switching device Q1, a heater L, and a power source 21, wherein the switching device Q1 is controlled by the temperature control unit 20, and in the case of being turned off, the power source 21 supplies power to the heater L, The heater L starts heating.

Optionally, the heating circuit 23 further includes a fuse F located between the power source 21 access point and the heater L.

Optionally, the switching device Q1 is a first transistor Q1, and the heating circuit 23 further includes a first resistor R1 connected between the power source 21 access point and the gate of the first transistor Q1. The gate of the first transistor Q1 is connected to the temperature control unit 20, and the other two stages are connected to the heater L and the ground point, respectively.

Optionally, the heating circuit 23 further includes a first capacitor C1 and a second resistor R2. The first capacitor C1 and the second resistor R2 are respectively connected between the gate of the first transistor Q1 and a ground point. The first capacitor C1 and the second resistor R2 form an RC protection circuit. Optionally, the heating circuit 23 further includes a second transistor Q2 whose gate is connected to the temperature control unit 20, and the other two stages are respectively connected to the grounding point and the gate of the first transistor Q1, wherein the second transistor Q2 is also It can be a triode whose base is connected to the temperature control unit 20, the emitter is connected to the ground point, and the collector is connected to the gate of the first transistor Q1.

Optionally, the heating circuit 23 further includes a second capacitor C2 and a third resistor R3, wherein the third resistor R3 is connected between the temperature control unit 20 and the gate of the second transistor Q2, and the second capacitor C2 is connected to the Between the gate of the second transistor Q2 and the ground point. The second capacitor C2 and the third resistor R3 constitute another RC protection circuit.

Optionally, the heater L is located inside the liquid crystal display 24.

In this embodiment, the heater L is specifically designed at the metal under the sealing frame (BM) of the cell portion inside the liquid crystal display panel 24, so that the temperature control is more accurate and more effective. Of course, the position of the heater L needs to be determined according to actual test results, and a plurality of heaters L can be disposed, which are evenly distributed at different positions inside the liquid crystal display 24, so that the heating of the liquid crystal display 24 is more uniform.

Further, the heater L may be an electronic device such as a heating resistor.

Optionally, the liquid crystal display includes a plurality of temperature sensors 22 respectively located at different positions inside the liquid crystal display 24 for collecting temperatures of the plurality of positions of the liquid crystal display 24, and inputting to the temperature control unit 20, so that the temperature control is performed. The unit 20 can calculate the average temperature of the liquid crystal display 24, compare the average temperature with a preset threshold, and when it is lower than the preset first threshold, send a control signal to the heating circuit to control the heating circuit to the liquid crystal display 24 Heating is performed. When the average temperature of the liquid crystal display 24 is higher than the preset second threshold, the control heating circuit is stopped to heat the liquid crystal display 24, so that the temperature control achieved is more accurate. The first threshold is smaller than the second threshold, and the specific value may be set according to actual needs.

Illustratively, the temperature sensor 22 in the embodiment of the present invention may be disposed at a position representative of the internal average temperature of the liquid crystal display panel 24, and the temperature sensor 22 may be a thin film transistor or a thermistor design.

In the embodiment provided by the present invention, the temperature control unit 20 shown in Fig. 2 is a single chip microcomputer having a function of receiving a command signal, making a judgment on the signal, and issuing a signal command. The temperature of the liquid crystal display 24 can be judged based on the value of the temperature sensor 22, and the heater L can be controlled to be heated so that the liquid crystal display is always in the operable temperature range.

The temperature sensor 22 in the embodiment of the present invention selects the AD7416, which is small in size, and is programmed to include a band gap temperature sensor and a 10-bit AD for monitoring and digitizing the temperature. The sensor also has a programmable threshold for comparing the measured temperature. Internal registers can be used to set the high and low temperature thresholds and provide an open-drain "over temperature indicator" output that is asserted when the set threshold is exceeded. Of course, the temperature sensor herein may also be other types of temperature sensors, and is not limited to the temperature sensor used in the embodiment of the present invention.

The liquid crystal display provided in the second embodiment of the present invention is specifically described as follows: As shown in FIG. 2, when the ambient temperature is too low, the temperature of the liquid crystal display 24 is too low, causing abnormal operation thereof. When the average temperature of the liquid crystal display 24 is lower than the preset first threshold, the heater L inside the liquid crystal display 24 is activated, and the heating temperature is continuously heated. When the average temperature of the liquid crystal display 24 is higher than the preset second threshold. At this time, the heater L is turned off.

Specifically, the single chip microcomputer first determines the operating temperature of the liquid crystal display 24 according to the temperature in the liquid crystal display screen collected by the temperature sensor 22. When the working environment temperature of the liquid crystal display 24 is lower than 0 ° C, the heating circuit 23 works, when the liquid crystal display When the operating temperature of the panel 24 is between 0 ° C and 20 ° C, if the heating circuit 23 is heating at this time, the heating is continued, and if the current heating circuit 23 is not heated, no heating is required. When the operating temperature of the liquid crystal display panel 24 is higher than 20 ° C, the heating circuit 23 stops heating.

As shown in FIG. 2, when the temperature sensor 22 senses that the temperature of the liquid crystal display 24 is too low (when the ambient temperature is too low, the temperature of the liquid crystal display is too low to cause abnormal operation), the temperature sensor 22 transmits the temperature signal to The single chip microcomputer sends a start signal through the command, the first transistor Q1 and the second transistor Q2 are turned on, the heater L starts to work, and the heating temperature is continuously heated. After reaching the predetermined temperature, the single chip microcomputer receives the instruction of the temperature sensor 22, and outputs the shutdown signal. A transistor Q1 and a second transistor Q2 are turned off, and the heater L is turned off.

At the same time, the RC circuit composed of the second capacitor C2 and the third resistor R3 increases the time during which the switching signal of the first transistor Q1 is turned on and off, thereby reducing the impact of the heating circuit on the power supply circuit.

In order to better control the operating temperature of the liquid crystal display 24, the single-chip microcomputer can be more specifically programmed to achieve more strict control on the working environment of the liquid crystal display 24, such as reducing the operating temperature range, so that the liquid crystal display 24 is continuously maintained. Within a reasonable temperature range. In addition, the MCU can also communicate with the LCD 24 to adjust the internal voltage of the LCD 24.

The temperature control unit and the outside of the liquid crystal display are made of heat insulating material to make the heat preservation device, and the heat is stored and accumulated by the heat insulating device, so that the liquid crystal display can work normally at a low temperature, which can reduce the power consumption of the heater. Among them, the heat preservation device can be designed according to the actual situation, such as vacuum insulation, material insulation and so on.

The liquid crystal display provided in the first embodiment of the present invention is the liquid crystal display provided in the second embodiment of the present invention. A single device diagram of the display device. Of course, the heating circuit in the liquid crystal display is not limited to the two heating circuits provided in the embodiments of the present invention, such as: driving the gate to the liquid crystal on the glass (Gate On Glass, GOA). When the display screen is low-temperature start-up, the phenomenon that the gate driving voltage is too low is easy to occur, and the gate driving voltage temperature compensation circuit can be added at the same time, which is integrated with the liquid crystal display provided in the embodiment of the present invention.

It is apparent that those skilled in the art can make various modifications and variations to the invention without departing from the spirit and scope of the invention. Thus, it is intended that the present invention cover the modifications and variations of the inventions

Claims

claims

1. A liquid crystal display, including a temperature control unit, a temperature sensor and a heating circuit, where the temperature sensor is used to transmit the temperature of the liquid crystal display screen to the temperature control unit; the temperature control unit is used to measure the temperature of the liquid crystal display screen based on the temperature sensor. , to control the operation of the heating circuit; the heating circuit is used to heat the LCD display according to the control of the temperature control unit.

2. The liquid crystal display according to claim 1, wherein the heating circuit includes: a switching device, a heater and a power supply, wherein the switching device is controlled by a temperature control unit, causing the power supply to power the heater when turned off. , the heater starts heating.

3. The liquid crystal display according to claim 2, wherein the heating circuit further includes a fuse located between the power access point and the heater.

4. The liquid crystal display according to claim 3, wherein the switching device is a first transistor, the heating circuit further includes a first resistor, the first resistor is connected to the power access point and the gate of the first transistor. Between them, the gate of the first transistor is connected to the temperature control unit, and the other two stages are connected to the heater and the ground point respectively.

5. The liquid crystal display according to claim 4, wherein the heating circuit further includes a first capacitor and a second resistor, and the first capacitor and the second resistor are respectively connected between the first transistor gate and the ground point.

6. The liquid crystal display according to claim 5, wherein the heating circuit further includes a second transistor, the gate of which is connected to the temperature control unit, and the other two stages are connected to the ground point and the gate of the first transistor respectively.

7. The liquid crystal display according to claim 6, wherein the heating circuit further includes a second capacitor and a third resistor, wherein the third resistor is connected between the temperature control unit and the gate of the second transistor, and the second capacitor Connected between the gate of the second transistor and ground.

8. The liquid crystal display according to claim 7, wherein the heater is located inside the liquid crystal display screen.

9. The liquid crystal display according to claim 8, wherein the heating circuit includes a plurality of heaters, wherein the plurality of heaters are connected in series or in parallel and are located at different positions inside the liquid crystal display screen.

10. The liquid crystal display according to claim 1, wherein the liquid crystal display includes a plurality of temperature sensors respectively connected to the temperature control unit, located at different positions inside the liquid crystal display screen. 6

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