CN103412426B - a liquid crystal display - Google Patents

Abstract

The invention discloses a kind of liquid crystal display, in order to widen the low-temperature working scope of LCDs, guarantee that it normally can work and have response speed faster in low temperature environment.Described liquid crystal display comprises temperature control unit, temperature sensor and heater circuit, and temperature sensor is used for the temperature of LCDs to be transferred to temperature control unit; Temperature control unit is used for the temperature of the LCDs gathered according to temperature sensor, determines that whether controlling heater circuit is LCDs heating; Heater circuit, for the control according to temperature control unit, is LCDs heating.

Description

a liquid crystal display

technical field

The invention relates to the technical field of displays, in particular to a liquid crystal display.

Background technique

When the ambient temperature of the liquid crystal display is lower than 0°C, the liquid crystal material will become viscous, and when the temperature is lower, the liquid crystal material will even "crystallize", which will cause the display screen to change color and brightness when the liquid crystal display starts working at a low temperature. Low, "smearing" phenomenon appears, in severe cases, graphics and image display cannot be seen clearly, and cannot meet the requirements of some special environmental conditions.

In order to make the liquid crystal display work normally at low temperature, the prior art proposes to heat the liquid crystal of the liquid crystal display, but this often causes the liquid crystal to flow out or be difficult to restore. In addition, there is another way in the existing technology: to increase the brightness of the liquid crystal display, that is, to increase the backlight tube, and to turn on the backlight tube at low temperature (-40°C) through the developed special high-voltage strip. Among them, the high-voltage strip can generate 2000V ～3200V start-up voltage, the huge heat generated by the backlight tube heats up the liquid crystal. This method kills two birds with one stone. It not only solves the problem of low-temperature operation of the liquid crystal, but also solves the problem of visibility under sunlight. This method is referred to as: brightening Way.

The above-mentioned methods have many hidden dangers in quality: many auxiliary parts are added, which reduces reliability; assembly and production are more troublesome, and defective products are easily caused, and the defective rate is high; the ability of devices to resist shock and vibration is reduced; the aging speed is extremely fast , rising at an accelerated rate, especially in the way of brightening, the lifespan is only 1/10 of the normal lifespan.

In addition, some foreign companies have developed wide-temperature liquid crystal materials with relatively high clearing point, low viscosity coefficient, and relatively consistent threshold characteristics in a wide temperature range. However, due to its high price, it is not easy to popularize and apply.

In addition, the new low-temperature reinforced liquid crystal display has achieved a breakthrough in technology. On the premise that it is not necessary to open the interior of the liquid crystal display module assembly and install the heater, it can solve the problem of micro-power heating of the liquid crystal display. This method 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 its application range is limited to a certain extent.

Contents of the invention

An embodiment of the present invention provides a liquid crystal display, which is used to widen 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 faster response speed.

According to a liquid crystal display provided by an embodiment of the present invention, the liquid crystal display includes: a temperature control unit, a temperature sensor and a heating circuit, the temperature sensor is used to transmit the temperature of the liquid crystal display to the temperature control unit; the temperature control unit is used to The temperature of the liquid crystal display screen collected by the temperature sensor controls the operation of the heating circuit, 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 controlling according to the temperature control unit. The LCD screen is heating up.

According to the liquid crystal display provided by the embodiment of the present invention, the liquid crystal display can realize the operation of the liquid crystal display in an extremely low temperature range, and can automatically control the temperature in the liquid crystal display when the external environment changes, without manual control, and adapts to the environment. strong ability.

Preferably, the heating circuit includes: a switch device, a heater and a power supply, wherein the switch device is controlled by the temperature control unit, and when it is turned off, the power supply supplies power to the heater, and the heater starts to heat.

In this way, when the heater starts to heat, the low-temperature working range of the liquid crystal display screen can be widened.

Preferably, the heating circuit further includes a fuse located between the power access point and the heater.

In this way, the fuse is used for overcurrent protection, which can effectively prevent devices in the heating circuit from being burned out.

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

In this way, the first transistor whose gate is connected to the temperature control unit acts as a switch, and the transistor is used as a switching device, which is convenient and simple, and is easy to implement. Among them, using the first resistor as a shunt resistor can protect the current from burning out due to excessive current device, but also simple and easy to implement.

Preferably, 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 gate of the first transistor and the ground point.

In this way, the RC circuit composed of the first capacitor and the second resistor prolongs the turn-on and turn-off time of the switch signal of the first transistor, and reduces the impact of the heating circuit on the power supply circuit.

Preferably, 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 respectively connected to the ground point and the gate of the first transistor.

In this way, the function of the second transistor is the same as that of the first transistor, and it is a switching device in the heating circuit, which is simple and easy in the design of the heating circuit.

Preferably, 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 is connected between the gate of the second transistor and the gate of the second transistor. between locations.

Like this, the RC circuit that is made up of the 3rd resistor that is connected between the gate of temperature control unit and the second transistor and the second capacitance that is connected between the gate of the second transistor and the ground point can play a role in the whole heating circuit. The role of filtering and voltage stabilization.

Preferably, 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, simple and easy to implement, and does not need to disassemble the liquid crystal display, thereby improving the reliability of the display.

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

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

Preferably, the liquid crystal display includes a plurality of temperature sensors respectively connected to the temperature control unit and located at different positions inside the liquid crystal display.

In this way, temperature sensors located at different positions inside the liquid crystal display can collect more accurate temperature values.

Description of drawings

FIG. 1 is a schematic diagram of a liquid crystal display provided by Embodiment 1 of the present invention;

FIG. 2 is a schematic diagram of another liquid crystal display provided by Embodiment 2 of the present invention.

Detailed ways

An embodiment of the present invention provides a liquid crystal display, which is used to widen 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 faster response speed.

A detailed introduction to the technical solutions provided by the embodiments of the present invention is given below.

Embodiment one:

As shown in Figure 1, a kind of liquid crystal display that the embodiment of the present invention provides, described liquid crystal display comprises: temperature control unit 10, temperature sensor 12 and heating circuit 13, and temperature sensor 12 is used for transmitting the temperature of liquid crystal display screen 14 to Temperature control unit 10; temperature control unit 10 is used to determine whether to control the heating circuit 13 to heat the liquid crystal display screen 14 according to the temperature of the liquid crystal display screen 14 collected by the temperature sensor 12; the heating circuit 13 is used to control according to the temperature control unit 10 , to heat the liquid crystal display screen 14 .

Preferably, the heating circuit 13 includes: a switching device Q, a heater L and a power supply 11, wherein the switching device Q is controlled by the temperature control unit 10, and when it is turned off, the power supply 11 supplies power to the heater L, heating The device L starts to heat up.

Wherein, the switching device Q is 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 supply 11, and the other end is connected to the transistor Q.

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

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

Preferably, the liquid crystal display includes a plurality of temperature sensors 12 respectively connected to the temperature control unit 10 and located at different positions inside the liquid crystal display 14 .

Embodiment two:

As shown in Fig. 2, the liquid crystal display that another embodiment of the present invention provides, described liquid crystal display comprises: temperature control unit 20, temperature sensor 22 and heating circuit 23, and temperature sensor 22 is used for transmitting the temperature of liquid crystal display screen 24 to The temperature control unit 20; the temperature control unit 20 is used to determine whether to control the heating circuit 23 to heat the liquid crystal display screen 24 according to the temperature of the liquid crystal display screen 24 collected by the temperature sensor 22; the heating circuit 23 is used to control the liquid crystal display screen 24 according to the temperature control unit 20 , to heat the liquid crystal display screen 24 .

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

Preferably, the heating circuit 23 includes: a switching device Q1, a heater L, and a power supply 21, wherein the switching device Q1 is controlled by the temperature control unit 20, and when it is turned off, the power supply 21 supplies power to the heater L to heat The device L starts to heat up.

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

Preferably, the switching device Q1 is a first transistor Q1, and the heating circuit 23 further includes a first resistor R1, the first resistor R1 is connected between the access point of the power supply 21 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 respectively connected to the heater L and the ground.

Preferably, the heating circuit 23 further includes a first capacitor C1 and a second resistor R2, and the first capacitor C1 and the second resistor R2 are respectively connected between the gate of the first transistor Q1 and the ground point. The first capacitor C1 and the second resistor R2 form an RC protection circuit.

Preferably, the heating circuit 23 further includes a second transistor Q2, the gate of which is connected to the temperature control unit 20, and the other two stages are respectively connected to the ground point and the gate of the first transistor Q1, wherein the second transistor Q2 is also connected to the ground point and the gate of the first transistor Q1. It may be a triode, the base of which 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 .

Preferably, 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 second transistor Q2. Between the gate of the second transistor Q2 and the ground point. The second capacitor C2 and the third resistor R3 form another RC protection circuit.

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

Among them, the heater L is specifically designed on the metal part under the sealing frame (BM) of the cell (cell) part inside the liquid crystal display 24, so that the temperature control is more accurate and more effective. Of course, the placement position of the heater L needs to be According to the actual test results, multiple heaters L can be arranged, evenly distributed in different positions inside the liquid crystal display 24, so as to make the heating of the liquid crystal display 24 more uniform.

Wherein, the heater L may adopt electronic devices such as heating resistors.

Preferably, the liquid crystal display includes a plurality of temperature sensors 22, which are respectively located at different positions inside the liquid crystal display 24, and are used to collect the temperatures of multiple positions of the liquid crystal display 24, and input them to the temperature control unit 20, so that the temperature control The unit 20 can calculate the average temperature of the liquid crystal display screen 24, compare the average temperature with the preset threshold value, and when it is lower than the preset first threshold value, send a control signal to the heating circuit, and control the heating circuit to control the temperature of the liquid crystal display screen 24. Heating is performed, and when the average temperature of the liquid crystal display 24 is higher than the preset second threshold, the control of the heating circuit to heat the liquid crystal display 24 is stopped, so that the temperature control realized will be more accurate. Wherein, the first threshold is smaller than the second threshold, and the specific value can be set according to actual needs.

Preferably, the temperature sensor 22 in the embodiment of the present invention is designed at a position that can represent the average temperature inside the liquid crystal display 24, and the temperature sensor 22 can be designed by using a thin film transistor or a thermistor.

In the embodiment provided by the present invention, the temperature control unit 20 shown in FIG. 2 is a single-chip microcomputer, which has the functions of receiving command signals, making judgments on the signals and sending out signal commands. The temperature of the liquid crystal display 24 can be judged according to the value of the temperature sensor 22, and the heater L is controlled to heat, so that the liquid crystal display is always within a workable temperature range.

The temperature sensor 22 in the embodiment of the present invention selects AD7416, which is small in size and simple in programming. It includes a bandgap temperature sensor and a 10-bit AD sensor for monitoring and digitizing the temperature, and a programmable threshold. to compare the measured temperature. The internal registers can be used to set high and low temperature thresholds, and provide an open-drain "over-temperature indicator" output. When the threshold is exceeded, the output is valid. Of course, the temperature sensor here can also be other The temperature sensor of the model is not limited to the temperature sensor used in the embodiment of the present invention.

The working process of the liquid crystal display provided in the second embodiment of the present invention will be described in detail below:

As shown in Figure 2, when the external environment temperature is too low, the temperature of the liquid crystal display 24 will also be too low and cause its abnormal operation, when the average temperature of the liquid crystal display 24 perceived by the single chip is lower than the preset first threshold, Start the heater L inside the liquid crystal display 24 to continuously heat up the temperature, and turn off the heater L when the average temperature of the liquid crystal display 24 is higher than the preset second threshold.

Specifically, the single-chip microcomputer first judges the working temperature of the liquid crystal display 24 according to the temperature in the liquid crystal display 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 24 When the working temperature is between 0° C. and 20° C., if the heating circuit 23 is heating at this time, then continue heating; if the current heating circuit 23 is not heating, then no heating is required. When the operating temperature of the liquid crystal display 24 is higher than 20° C., the heating circuit 23 stops heating.

As shown in Figure 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 will also be too low and cause abnormal operation), the temperature sensor 22 sends a temperature signal to Single-chip microcomputer, 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, continuously heats up the temperature, and after reaching the predetermined temperature, the single-chip microcomputer receives the command of the temperature sensor 22 and outputs a shutdown signal, The first transistor Q1 and the second transistor Q2 are turned off, turning off the heater L.

At the same time, the RC circuit composed of the second capacitor C2 and the third resistor R3 increases the turn-on and turn-off time of the switch signal of the first transistor Q1, and reduces 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, more specific programming can be carried out to the single-chip microcomputer, and the working environment of the liquid crystal display 24 can be controlled more strictly, such as narrowing the operating temperature range, so that the liquid crystal display 24 can be continuously maintained. within a reasonable temperature range. In addition, the single-chip microcomputer can also communicate with the liquid crystal display 24 to adjust the internal voltage of the liquid crystal display 24 .

The temperature control unit and the exterior of the LCD screen are made of heat insulating material to make a thermal insulation device, and the heat is stored and accumulated through the thermal insulation device, so that the LCD screen can work normally at low temperature, which can reduce the power consumption of the heater. Among them, the heat preservation device can be specifically designed according to the actual situation, such as vacuum heat preservation, material heat preservation, etc.

The liquid crystal display provided in Embodiment 1 of the present invention is a simple device diagram of the liquid crystal display provided in Embodiment 2 of the present invention. Certainly, the heating circuit in the liquid crystal display is not limited to the two heating circuits provided in the embodiment of the present invention, such as: It is easy to cause the gate drive voltage to be too low when the LCD on the glass (Gate On Glass, GOA) is driven at low temperature, and the gate drive voltage temperature compensation circuit can be added at the same time, which is the same as the liquid crystal display provided by the embodiment of the present invention. The display blends into one.

Obviously, those skilled in the art can make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalent technologies, the present invention also intends to include these modifications and variations.

Claims (7)

1. a liquid crystal display, is characterized in that, described liquid crystal display comprises temperature control unit, temperature sensor and heater circuit, and temperature sensor is used for the temperature of LCDs to be transferred to temperature control unit; Temperature control unit is used for the temperature of the LCDs gathered according to temperature sensor, controls heater circuit work; Heater circuit, for the control according to temperature control unit, is LCDs heating; Described heater circuit comprises: switching device, well heater, power supply, the second electric capacity and the 3rd resistance, and wherein, switching device is controlled by temperature control unit, makes power supply be heating installation power supply when closing, and well heater starts heating; Wherein:

Described switching device comprises the first transistor and transistor seconds, and the grid of described transistor seconds is connected with temperature control unit, and two-stage is connected with the grid of the first transistor with earth point respectively in addition; The other two-stage of described the first transistor is connected with earth point with well heater respectively;

Described 3rd resistance is connected between temperature control unit and the grid of transistor seconds;

Described second electric capacity is connected between the grid of transistor seconds and earth point.

2. liquid crystal display according to claim 1, is characterized in that, described heater circuit also comprises the fuse between plant-grid connection point and well heater.

3. liquid crystal display according to claim 2, is characterized in that, described heater circuit also comprises the first resistance, and this first resistance is connected between plant-grid connection point and the grid of the first transistor.

4. liquid crystal display according to claim 3, is characterized in that, described heater circuit also comprises the first electric capacity and the second resistance, and the first electric capacity and the second resistance are connected between first crystal tube grid and earth point.

5. liquid crystal display according to claim 4, is characterized in that, described well heater is positioned at LCDs inside.

6. liquid crystal display according to claim 5, is characterized in that, described heater circuit comprises multiple well heater, wherein, connected in series or in parallel between multiple well heater, lays respectively at the diverse location of LCDs inside.

7. liquid crystal display according to claim 1, is characterized in that, described liquid crystal display comprises multiple temperature sensor be connected with described temperature control unit respectively, is positioned at the diverse location of LCDs inside.