JP2007065310A - Liquid crystal display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To efficiently increase the response speed of a liquid crystal display element 10, under a low-temperature environment. <P>SOLUTION: The liquid crystal display device 1 is equipped with a liquid crystal display element 10 and a sheet-like heater 20 provided having the front opposite the back of the liquid crystal display element 10. Furthermore, a far-infrared radiation substance layer 23 is formed on the front of the sheet type heater 20. The far-infrared radiation substance layer 23 is formed by applying ceramic. The liquid crystal display device may be equipped with a backlight 30 which is provided on the back side of the heater 20 and emits sheet-like light to the back side of the liquid crystal display element 10 and in this case, translucent materials having are used for the heater 20 and far-infrared radiation substance layer 23. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a liquid crystal display device, and more particularly, to a liquid crystal display device including a planar heater on the back side of a liquid crystal display element.

In recent years, display devices using liquid crystal display elements are widely used in mobile phones, televisions, computers, car navigation panels, automobile meter panels, and the like.
The liquid crystal display element is configured by sandwiching a liquid crystal between substrates disposed to face each other. Then, by applying a voltage to the liquid crystal sandwiched between the two substrates and changing the alignment of the liquid crystal molecules, the transmission of light between the substrates arranged facing each other is controlled.

By the way, the liquid crystal display element generally has a property that the response time required for changing the alignment of liquid crystal molecules after applying a voltage is significantly delayed at a low temperature.
For this reason, in automotive meter panels and car navigation panels used at low temperatures, there is a heater that radiates heat toward the liquid crystal display elements in order to improve the response characteristics of the liquid crystal display elements at low temperatures. Sometimes used.
As a liquid crystal display device using a heater, for example, a technique described in Patent Document 1 is known.
Japanese Unexamined Patent Publication No. 2003-29288 (particularly FIG. 1)

  However, even if the technique of Patent Document 1 is applied to an automobile meter panel or car navigation panel, for example, at a low temperature of −30 ° C. to 0 ° C., it takes a while until the response speed of the liquid crystal display element is sufficiently obtained. It was over. For this reason, immediately after starting the engine of the automobile, accurate information is not displayed on the liquid crystal display element, for example, information necessary for driving such as the number of revolutions of the engine and imaging information of a camera disposed behind the automobile. Could not start the car.

Here, in order to increase the response speed of the liquid crystal display element, it is possible to increase the voltage applied to the heater to increase the heat of the heater. However, even if the voltage applied to the heater is simply increased, the liquid crystal display In some cases, heat is trapped in the element, and the liquid crystal display element is deformed.
The present invention has been made to solve such problems, and an object thereof is to provide a liquid crystal display device capable of efficiently increasing the response speed of a liquid crystal display element in a low temperature environment.

The liquid crystal display device according to the present invention includes a liquid crystal display element and a planar heater provided with the front surface facing the back surface of the liquid crystal display element, and the far-infrared emitting material layer is on the front surface or the back surface of the heater. It is characterized by being formed.
By adopting such a configuration, the far-infrared emitting material layer radiates the heat of the heater as electromagnetic waves through the far-infrared emitting material layer in addition to normal heat radiation, so it is not necessary to increase the heater heat. The liquid crystal display element can be quickly heated, and the response speed of the liquid crystal display element in a low temperature environment can be increased efficiently.

Preferably, the heater has a substrate provided with a front surface facing the back surface of the liquid crystal display element, and an electrode formed on the entire front surface of the substrate or substantially the entire back surface, and emits far-infrared radiation. The material layer is formed on the electrode. The heater is provided with the surface on which the electrodes are formed facing the back surface of the liquid crystal display element.
Thereby, the heat generated by the heater electrode can be directly transferred from the electrode to the far-infrared emitting material layer, and can be efficiently radiated through the far-infrared emitting material layer. As a result, the liquid crystal display element can be quickly warmed, and the response speed of the liquid crystal display element in a low temperature environment can be increased more efficiently.

  The far-infrared emitting material layer is formed by applying ceramics. Thereby, a far-infrared radiation material layer can be formed easily.

Further, it is further provided with a planar light source body that is provided on the back side of the heater and irradiates planar light toward the back side of the liquid crystal display element, and the heater and the far-infrared emitting material layer have translucency. It is.
As described above, since the heater and the far-infrared emitting material layer have translucency, the liquid crystal display element can be efficiently irradiated with the planar light of the planar light source body.

  According to the present invention, the response speed of the liquid crystal display element in a low temperature environment can be increased efficiently.

Embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a schematic diagram showing a configuration of a liquid crystal display device according to an embodiment of the present invention. FIG. 1 (a) is a front view of the liquid crystal display device according to the embodiment of the present invention. FIG. 2B is a cross-sectional view taken along the line AA in FIG.
As shown in FIGS. 1A and 1B, the liquid crystal display device 1 includes a liquid crystal display element 10, a heater 20, and a backlight 30 as a planar light emitter. Note that a liquid crystal display device may be configured by the liquid crystal display element 10 and the heater 20 without including the backlight 30.

First, the configuration of the liquid crystal display element 10 will be described with reference to the drawings.
As shown in FIG. 1A and FIG. 1B, the liquid crystal display element 10 is configured such that a first transparent substrate 11 and a second transparent substrate 12 formed in a rectangular shape are opposed to each other. . A plurality of transparent electrodes (not shown) are formed in stripes on the inner surface of the first transparent substrate 11. A plurality of transparent electrodes (not shown) are formed on the inner surface of the second transparent substrate 12 in a stripe shape so as to be orthogonal to the plurality of transparent electrodes formed on the inner surface of the first transparent substrate 11. Is formed.

  Further, the first and second transparent substrates 11 and 12 are joined by a sealing material (not shown) provided along the periphery of the first transparent substrate 11, and a liquid crystal injection port (not shown). After the liquid crystal is injected from, the liquid crystal injection port is sealed with a sealing material (not shown).

An alignment film (not shown) is stacked on a plurality of transparent electrodes (not shown) formed on the inner surfaces of the first and second transparent substrates 11 and 12.
By applying a voltage between the two electrodes formed on the inner surfaces of the first and second transparent substrates, the arrangement of the liquid crystal molecules between the two electrodes is changed, so that the first and second transparent substrates 11, 12 are changed. The transmission of light between the two.

  As shown in FIG. 1A and FIG. 1B, the first and second transparent substrates 11 and 12 are formed in a rectangular shape using, for example, light-transmitting glass, polycarbonate, acrylic resin, or the like. . The plurality of transparent electrodes formed on the inner surfaces of the first and second transparent substrates are made of ITO (Indium Tin Oxide) using, for example, a photolithography method.

  As shown in FIG. 1A, the end portion of the second transparent substrate 12 extends beyond the end portion of the first transparent substrate 11 on one side of the liquid crystal display element 10. On the extended portion 12a of the second transparent substrate, a drive circuit 14 is mounted by COG (Chip On Glass), and a plurality of electrode terminals 13 are arranged. A flexible printed circuit board (not shown) is connected to the electrode terminal 13 by, for example, thermocompression bonding.

Next, the structure of the heater 20 is demonstrated based on figures.
As shown in FIG. 1B, the heater 20 is formed in a planar shape, and is provided with the front surface facing the back surface of the liquid crystal display element 10. As shown in FIG. 1B, a certain gap d (for example, 100 μm) is provided between the front surface of the heater 20 and the back surface of the liquid crystal display element 10. In addition, when the fixed gap | interval d is very small, the water vapor | steam in air will accumulate in the gap | interval d, and the problem that a polka dot may be produced may arise.

  In addition, it is conceivable that the back surface of the liquid crystal display element 10 and the front surface of the heater 20 are brought into close contact with each other without providing the gap d. However, a special adhesive that can cope with a sudden temperature difference is necessary, and repair is extremely necessary. It is difficult to do so, and there is a concern that the yield may decrease when foreign matter is mixed between the back surface of the liquid crystal display element 10 and the front surface of the heater 20, which increases the manufacturing process and cost of the liquid crystal display device 1. There is a problem of being connected. For this reason, a gap d of about 100 μm is provided.

Further, as shown in FIG. 1B, the heater 20 includes a rectangular transparent substrate 21 formed of glass or the like, and a substantially entire surface on the front surface of the transparent substrate 21 made of ITO using, for example, photolithography. And the formed transparent electrode 22. Here, although the transparent substrate 21 and the transparent electrode 22 have translucency, in the case where the backlight 30 is not provided on the back side of the heater 20, it is particularly necessary to use a translucent member. There is no.
The transparent electrode 22 has voltage input terminals (not shown) on one side of the transparent substrate 21 and on the opposite side. Then, by applying a voltage between both terminals, a current flows through the transparent electrode 22 formed on the entire surface of the transparent substrate 21, and heat is emitted from the transparent electrode 22.

In addition, as shown in FIG. 1B, the far-infrared radiation material layer 23 is laminated in close contact with the transparent electrode 22 of the heater 20.
Ceramics are used as the main material of the far-infrared emitting material layer 23. The far-infrared emitting material layer 23 is configured, for example, by applying a paint containing ceramics as a main component onto the transparent electrode 22 of the heater 20 with a brush or the like. Thereby, the far-infrared radiation material layer 23 can be easily formed. In addition, as a coating material containing ceramics, there exists a thing which added ceramics to the diluent, the epoxy resin, etc., for example. In addition, since an epoxy resin is excellent in heat resistance, it is suitable for such a use.

  Here, the far infrared ray refers to an electromagnetic wave having a wavelength of about 20 μm to 100 μm among infrared rays. In addition, ceramics as far-infrared emitting materials are composed of aggregates of metal oxides such as silicic acid oxide, titanium oxide, aluminum oxide, iron oxide, magnesium oxide, and the potential difference from each of these materials. Is generated and radiates electromagnetic wave far infrared rays. For example, platinum, tourmaline, silver, or the like may be used as the catalyst.

  Thus, by forming the far-infrared emitting material layer 23 on the front surface of the heater 20, the heat generated by the heater 20 is radiated as electromagnetic waves through the far-infrared emitting material layer 23 in addition to normal heat radiation. Therefore, the liquid crystal display element 10 can be quickly heated, and the response speed of the liquid crystal display element 10 in a low temperature environment can be increased efficiently. Further, since the heat generated by the heater 20 is radiated as an electromagnetic wave through the far-infrared radiation material layer 23, the surface temperature of the heater 20 does not increase remarkably. In addition, it is possible to efficiently warm the liquid crystal display element 10 without increasing the heater heat by increasing the voltage applied to the heater 20, and to efficiently increase the response speed of the liquid crystal display element 10 in a low temperature environment. Can do.

  The heater 20 includes a transparent substrate 21 provided with a front surface facing the back surface of the liquid crystal display element 10 and a transparent electrode 22 formed on substantially the entire front surface of the transparent substrate 21. Since the infrared radiation material layer 23 is formed on the transparent electrode 22, the heat generated by the transparent electrode 22 of the heater 20 can be directly transferred from the transparent electrode 22 to the far infrared radiation material layer 23. Radiation is possible through the material layer 23. As a result, the liquid crystal display element 10 can be quickly warmed, and the response speed of the liquid crystal display element 10 in a low temperature environment can be increased more efficiently.

  Further, by providing the surface of the heater 20 on which the transparent electrode 22 is formed facing the back surface of the liquid crystal display element 10, the heat generated by the transparent electrode 22 of the heater 20 passes through the transparent substrate 21 of the heater 20. However, it is possible to radiate heat radiation and electromagnetic waves directly toward the liquid crystal display element 10. As a result, the liquid crystal display element 10 can be quickly warmed, and the response speed of the liquid crystal display element 10 in a low temperature environment can be increased more efficiently.

Next, the structure of the backlight 30 is demonstrated based on figures.
As shown in FIG. 1B, the backlight 30 as the planar light source body is provided on the back side of the heater 20. The backlight 30 includes a light guide plate 31, a prism sheet (not shown) and a diffusion sheet (not shown) stacked on the front surface of the light guide plate 31, and a reflection sheet (not shown) provided on the back surface of the light guide plate 31. And a light source 31 such as a light emitting diode (LED) disposed on the side of the light guide plate 31.

  Here, the reflection sheet (not shown) reflects the light from the light source 32 toward the liquid crystal display element 10 side. The light guide plate 31 guides the light from the light source 32 so that the light is uniformly incident on the entire display area of the liquid crystal display element 10. The prism sheet (not shown) collects the light from the light source 31 incident from the light guide plate 32 toward the liquid crystal display element 10. The diffusion sheet (not shown) diffuses the light of the light source 32 incident from the prism sheet, and makes the brightness of the display area of the liquid crystal display element 10 uniform.

  When the backlight 30 is provided on the back side of the heater 20, the far-infrared emitting material layer 23 has a light transmitting property. In addition, since the transparent substrate 21 and the transparent electrode 22 are originally formed of a transparent material, they have translucency. Thus, by providing the heater 20 and the far-infrared emitting material layer 23 with translucency, the liquid crystal display element 10 can be efficiently irradiated with the planar light of the backlight 30 as the planar light emitter.

Next, the relationship between the temperature of the liquid crystal display element 10 of the liquid crystal display device 1 according to the embodiment of the present invention and the voltage application time to the heater 20 will be compared with the conventional one.
FIG. 2 is a diagram showing the relationship between the temperature of the liquid crystal display element of the liquid crystal display device according to the embodiment of the present invention and the voltage application time to the heater in comparison with the conventional one.
First, the test sample will be described.

In the product of the present invention and the conventional product, a 60 mm × 80 mm rectangular liquid crystal display element 10 and a 60 mm × 80 mm rectangular heater 20 were used.
The product according to the present invention is different from the conventional product in which the far infrared radiation layer 23 is not formed on the front surface of the heater 20 in that the far infrared radiation layer 23 is formed on the front surface of the heater 20. Further, as shown in FIG. 1B, the transparent electrode 22 and the far-infrared radiation layer 23 of the heater 20 are arranged between the liquid crystal display element 10 and the transparent substrate 21 of the heater 20. Further, the gap d between the back surface of the liquid crystal display element 10 and the heater 20 was set to 100 μm.

For the far-infrared radiation layer 23, a soft type of “first sticking first” (registered trademark) made by Oki Electric Cable Co., Ltd. The heat radiation sheet “First to paste first” soft type manufactured by Oki Electric Cable Co., Ltd. has a feature that the thermal emissivity of the surface at 100 ° C. is 0.96.
The test was performed such that the surface temperature of the heater 20 of the present invention product and the surface temperature of the conventional heater 20 were the same.

  As for the test results, as shown in FIG. 3, the surface temperature of the liquid crystal display element 10 rises according to the voltage application time to the heater 20 in both the product according to the present invention and the conventional product. It can be seen that the product according to the present invention in which 23 is formed is faster in the surface temperature of the liquid crystal display element 10 than the conventional product. That is, for example, the voltage application time required to increase the surface temperature of the liquid crystal display element from −30 ° C. to −10 ° C. is about 400 seconds (sec) in the conventional product, while the product of the present invention is used. Then, it was about 200 seconds (sec), which is about half of the conventional product.

  As described above, the far-infrared emitting material layer 23 is formed on the front surface of the heater 20, so that the far-infrared emitting material layer 23 applies the heat of the heater 20 to normal heat radiation, thereby forming the far-infrared emitting material layer 23. Therefore, it is possible to quickly increase the temperature of the liquid crystal display element 10 without increasing the heat of the heater 20, and efficiently increase the response speed of the liquid crystal display element 10 in a low temperature environment. Can do.

Next, a modification of the liquid crystal display device according to the embodiment of the present invention will be described with reference to the drawings. FIG. 3 is a cross-sectional view showing a configuration of a modified example of the liquid crystal display device according to the embodiment of the present invention, and is a cross-sectional view corresponding to the AA cut line in FIG.
In the description of the above embodiment, the transparent electrode 22 and the far-infrared radiation layer 23 of the heater 20 are disposed on the surface facing the back surface of the liquid crystal display element 10, whereas according to the embodiment of the present invention. In the modification of the liquid crystal display device, as shown in FIG. 3, the transparent electrode 22 and the far-infrared radiation layer 23 of the heater 20 are arranged on the surface opposite to the surface facing the back surface of the liquid crystal display element 10. It is different in point.

  Even when the liquid crystal display device is configured in this way, the heat generated by the transparent electrode 22 of the heater 20 can be directly transferred from the transparent electrode 22 to the far-infrared emitting material layer 23, and the far-infrared radiation can be efficiently performed. Radiation is possible through the material layer 23. As a result, the liquid crystal display element 10 can be quickly warmed, and the response speed of the liquid crystal display element 10 in a low temperature environment can be increased efficiently.

The above description is for explaining the embodiment of the present invention, and the present invention is not limited to the above embodiment. Moreover, those skilled in the art can easily change, add, and convert each element of the above embodiment within the scope of the present invention.
In the description of the above embodiment, a passive liquid crystal display device is used as an example. However, the present invention is not limited to this, and the invention according to this embodiment is applied to other types of liquid crystal display devices such as an active liquid crystal display device. Can also be adopted.

BRIEF DESCRIPTION OF THE DRAWINGS It is a schematic diagram which shows the structure of the liquid crystal display device which concerns on embodiment of this invention, Comprising: Fig.1 (a) is a front view of the liquid crystal display device which concerns on embodiment of this invention, FIG.1 (b) is FIG. It is sectional drawing in the AA cut line of Fig.1 (a). It is a figure which shows the relationship between the temperature of the liquid crystal display element of the liquid crystal display device which concerns on embodiment of this invention, and the voltage application time to a heater compared with the conventional one. It is sectional drawing which shows the structure of the modification of the liquid crystal display device which concerns on embodiment of this invention, Comprising: It is sectional drawing corresponding to the AA cut line of Fig.1 (a).

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 Liquid crystal display device, 10 Liquid crystal display element, 11 1st transparent substrate, 12 2nd transparent substrate, 13 Electrode terminal, 14 Drive circuit, 20 Heater, 21 Transparent substrate, 22 Transparent electrode, 23 Far-infrared radiation layer, 30 Backlight, 31 Light guide plate, 32 Light source

Claims (5)

A liquid crystal display element;
A planar heater provided with the front surface facing the back surface of the liquid crystal display element;
A liquid crystal display device, wherein a far-infrared emitting material layer is formed on a front surface or a back surface of the heater. The heater has a substrate provided with a front surface facing the back surface of the liquid crystal display element, and an electrode formed on substantially the entire front surface or the back surface of the substrate,
The liquid crystal display device according to claim 1, wherein the far-infrared emitting material layer is formed on the electrode.   The liquid crystal display device according to claim 2, wherein the heater is provided with a surface on which the electrode is formed facing a back surface of the liquid crystal display element.   The liquid crystal display device according to claim 1, wherein the far-infrared emitting material layer is formed by applying ceramics. A planar light source body that is provided on the back side of the heater and that emits planar light toward the back side of the liquid crystal display element;
The liquid crystal display device according to claim 1, wherein the heater and the far-infrared emitting material layer have translucency.

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