JP2009199745A - Temperature control system having backlight module - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a temperature control system having a backlight module. <P>SOLUTION: The temperature control system is used for the backlight module which raises luminance of a liquid crystal display device by increasing directly a light source amount of a backlight unit, and a control circuit adjusts low the emission luminance of a light-emitting module by combining with a pulse width modulation through measurement of the resistance value of at least one thermistor, and by lowering the temperature rise speed of the backlight unit, prevents that the whole of the related electronic elements does not operate normally due to remaining of heat generated from the light-emitting module or the durability lifetime is shortened. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a temperature control system having a backlight module, and more particularly to a temperature control system that appropriately adjusts the light emission luminance of a backlight module by a control circuit through measurement of a resistance value of a thermistor.

  Liquid crystals are organic compounds that are intermediate between solids and liquids, and are also compounds with a standard molecular arrangement. When heated above a certain temperature, it becomes a transparent liquid and cooled below a certain temperature. Then, it becomes a crystallized turbid state, and it is called liquid crystal because of these characteristics. Due to the basic characteristics of liquid crystal, the basic principle of liquid crystal display devices is that the liquid crystal is sealed in a glass box and the direction of the liquid crystal molecules changes when an electric field is applied. This change in direction changes the optical properties, and the polarizer transmits the light. You can change the gender and achieve a blinking effect.

However, in the case of a signboard display in an environment with sunlight or bright light in the external environment, the liquid crystal display device becomes thin because the reflected light or scattered light is too strong, and the display color is not clearly visible. The reason why it becomes impossible is that the screen image is blocked by reflected light or scattered light from the outside because the brightness of the display device body is insufficient, and at least the brightness of the liquid crystal display device is 1000 cd / The problem that the screen is blocked by the environmental light source cannot be improved unless it is raised to m ² or more.

  Increasing the amount of light source of the backlight unit is the most direct way to increase the brightness of the liquid crystal display device, and at the same time combined with a highly effective reflector, prism sheet to increase brightness, and a liquid crystal panel with a high aperture ratio If this is possible, the light utilization rate can be increased, thus achieving a high brightness effect.

  However, when the light is emitted, heat is generated in the light source itself. The greater the amount of light, the higher the total generated heat. As the lighting time of the backlight unit increases, the entire liquid crystal display module (Liquid Crystal Display Module, LCM) increases. As the temperature rises further, the product may overheat or display contrast may decrease, and the electronic device may overheat, making it impossible to work and even causing problems.

At present, the liquid crystal display device has a factor that makes it impossible to process due to the high temperature, so the luminance of the liquid crystal display product on the market is mostly around 300 cd / m ² , and combined with the semi-reflective design method It should be noted that the problem of reflection of an external light source is overcome by simply using a total reflection liquid crystal display device without using a backlight unit. However, even in these methods, the number of colors of the semi-reflective liquid crystal display device screen is reduced, the color purity is deteriorated, and the quality of the screen is affected. There is a problem.

  Therefore, in order to fundamentally solve the above-mentioned drawbacks, the main object of the present invention is to increase the number of light emitting sources and greatly increase the luminance of the backlight module, thereby adjusting the light emitting luminance of the light emitting source to emit light. It is possible to extend the useful life of the liquid crystal module by preventing the amount of source heat from continuing and preventing the related members and electronic elements from being overheated to reduce the effectiveness or shorten the lifetime.

  Based on the above object, the present invention proposes a temperature control system having a backlight module, which is used in a backlight module that directly increases the light source amount of the backlight unit to increase the luminance of the liquid crystal display device, and at least the backlight module is used. The light emitting module for providing the brightness of the light module, and at least one thermistor and a control circuit for detecting the temperature of the backlight module. The control circuit receives a signal of a resistance value change of the thermistor. By controlling the luminance output of the light emitting module, the temperature generation of the backlight module is adjusted, and the temperature rise rate is made slow and gradually lowered.

  The light emitting module includes a plurality of light emitting diodes or a plurality of cold cathode tubes, and the control circuit controls the luminance of the light emitting module by a pulse width modulation method.

  When the control circuit receives a resistance value of the thermistor lower than a reference value, the light emission brightness of the light emitting module is adjusted low, and when the control circuit receives a resistance value of the thermistor higher than a reference value, Without adjusting the light emission luminance of the light emitting module, the power necessary for the light emitting module is supplied to maintain the light emission luminance necessary for the light emitting module.

  The effect of the present invention is that the backlight module structure that increases the amount of light source of the backlight unit to increase the luminance of the liquid crystal display device is combined with the pulse width modulation of the control circuit through the measurement of the resistance value of the thermistor, The light emission brightness is adjusted to be low so that the temperature rise rate of the backlight module is slowed and gradually lowered. In addition, the amount of heat generated from the light emitting module is continuously maintained, and the temperature of the entire liquid crystal display module can be constantly raised to prevent normal operation. At the same time, the related members and electronic elements are less effective due to overheating. The lifetime can be prevented from being shortened.

  Although the detailed contents and technical description according to the present invention will be further described in the examples, it should be understood that the above examples are merely illustrative and should not be construed as limitations on the implementation of the present invention.

  In order to increase the brightness of the liquid crystal display module, increasing the amount of light source of the backlight unit is the most direct method. Therefore, the backlight unit incorporates many light emitting sources to increase the brightness of the liquid crystal display module (LCM). The higher the total amount of heat generated, the greater the amount of heat generated by the light source, especially as the backlight unit's lighting time increases, the temperature of the entire LCD module increases further, causing the product to overheat and display. There is a possibility that the contrast is lowered, and even the problem that the electronic device is overheated and the work cannot be performed and the operation is down is caused.

  As shown in FIG. 1, the present invention proposes a temperature control system having a backlight module, which is used in a backlight module that directly increases the amount of light source to increase the brightness of the liquid crystal display device, which is at least a pulse width modulation (PWM). ) Control circuit 10 for controlling the light emitting module 12 according to a method, and the light emitting module 12 includes a plurality of light emitting diodes or a plurality of cold cathode tubes, and provides the brightness of the backlight module. It also includes at least one thermistor 11 for detecting the temperature of the backlight module, and the thermistor 11 transmits a resistance value change signal to the control circuit 10, and the control circuit 10 transmits the luminance of the issuing module. By adjusting and controlling the output, the temperature change of the backlight module is adjusted, and the temperature rise rate is made slow and gradually lowered.

The surface brightness of the backlight module varies depending on the increase or decrease of the number of light emitting sources on the light emitting module 12. For example, if the backlight module contains 64 light emitting diode (LED) light emitting chips as a light source, the surface brightness of the backlight module is 30,780 cd / m ² , and the brightness passes through the liquid crystal panel. Then, the surface luminance of the liquid crystal display module (LCM) can be increased to 3,388 cd / m ² , and thus the high luminance is said to be blocked by the environmental light source as a signboard display in the environment of sunlight or bright light of the external environment. The problem can be improved.

In FIG. 2, when the lighting time of the light emitting source on the light emitting module 12 is extended, the amount of heat generated from the light emitting module 12 is constantly accumulated, the temperature of the backlight module gradually increases, and the temperature of the liquid crystal display module (LCM) is also increased. Ascend with this. At this time, by measuring the resistance value of the thermistor 11, the resistance value is transmitted to the control circuit 10, and when the resistance value of the thermistor 11 is lower than a preset reference value, The control circuit 10 adjusts the light emission luminance of the light emitting module 12 to be lowered by the pulse width modulation method, thereby reducing the heat amount of the light emitting module 12 and increasing the temperature increase rate of the backlight unit. Slow down slowly. In this way, the amount of heat generated from the light emitting module 12 is continuously accumulated, so that the temperature of the liquid crystal display module (LCM) is constantly raised to prevent normal operation, and at the same time, related members and electronic elements are overheated. The effect is not reduced or the life is not shortened.

  However, if the control circuit 10 receives a resistance value signal of the thermistor 11 higher than a preset reference value, it indicates whether the temperature of the backlight module is still not too high or has already fallen to a reasonable range. The control circuit 10 maintains a necessary pulse width, supplies necessary output power to the light emitting module 12, and maintains a necessary light emission luminance of the light emitting module 12. The light emission luminance of the light emitting module 12 is Do not adjust.

  With respect to a device that increases the surface luminance of a liquid crystal display module (LCM) by increasing the amount of light emission source of the backlight unit, the present invention addresses the problem that the total amount of heat generated increases as the amount of light source increases. Combined with the pulse width modulation of the control circuit through the measurement of the value, the light emission brightness of the light emitting module is adjusted to be low as appropriate, the temperature rise rate of the backlight unit can be slowed down and gradually lowered. The amount of heat generated will not continue and the liquid crystal display module will not be able to operate normally, thereby extending the useful life of the liquid crystal module, and at the same time, the related members and electronic elements will not be reduced in effectiveness or shortened life due to overheating. Can be.

Since the above description is only a preferred embodiment of the present invention and does not limit the scope of the present invention, all equivalent changes or modifications made based on the scope of the claims of the present invention It shall be included in the range.

It is the schematic of the temperature control system of an Example of this application. It is a judgment flowchart regarding a resistance value in the control circuit of the embodiment of the present application.

Explanation of symbols

10 control circuit 11 thermistor 12 light emitting module

Claims (2)

A light emitting module for providing brightness of the backlight module;
At least one thermistor for detecting the temperature change of the backlight module;
At least a control circuit for controlling the brightness of the light emitting module by a pulse width modulation (PWM) method;
The control circuit receives a signal indicating a change in the resistance value of the thermistor and controls the brightness output of the light emitting module to adjust the temperature of the backlight module, and the temperature control having a backlight module system. 2. The light emitting module according to claim 1, wherein the light emitting module includes one of a plurality of light emitting diodes (LEDs) and a plurality of cold cathode fluorescent lamps (CCFLs). Temperature control system having a backlight module.

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