JPH0210510Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention relates to a liquid crystal display device in which a plurality of liquid crystal display elements are stacked.

[Technical background of the invention and its problems]

In a liquid crystal display device, when it is necessary to perform a large number of displays within a certain area, a display device in which liquid crystal display elements are stacked in a multilayer structure is generally used. Such display devices include a method in which a plurality of liquid crystal display elements are stacked by filling liquid crystal material between two transparent substrates, and a method in which three or more transparent substrates are stacked and a liquid crystal material is filled between adjacent substrates. It is formed by either a filling method or a method combining the above two methods.

Furthermore, when a liquid crystal display device is used in a low-temperature environment, the viscosity of the liquid crystal material filled between the transparent substrates increases, and the optical response speed to the voltage applied to operate the display device decreases.
In order to prevent such problems from occurring, it is necessary to heat the liquid crystal display element. For this reason, methods such as installing a planar heating element on the surface of the liquid crystal display element have been adopted.

Conventionally, when a heating element is installed in a multilayer liquid crystal display device in this manner, the heating element is installed on the outermost substrate among the transparent substrates that constitute the multilayer liquid crystal display device. An overview of one example is shown in Figure 1. 1, 2,
3 and 4 are transparent substrates each having a transparent conductive film formed on its surface; 5 and 6 are liquid crystal materials filled between the substrates; 7 and 8 are insulating spacers attached between the substrates;
9 is an optical component such as a polarizing plate, and 10 is a heating element installed outside the transparent substrate 4.

When a planar heating element is installed on one side of a display device consisting of such multilayer elements, (assuming the number of elements is n) the first liquid crystal layer closest to the heating element and the n-th liquid crystal layer furthest A temperature gradient will occur across the layers, and as a result, the response speeds of individual individual liquid crystal display elements will differ, and when display is performed as a whole in a multilayer liquid crystal display, the response speeds of individual display segments will be uneven. There was a drawback that this occurred. Furthermore, in order to raise the liquid crystal layer furthest from the heating element to the desired temperature, it is necessary to heat the liquid crystal display element facing the heating element more than necessary. There was a risk of thermal damage to the For this reason, it is conceivable to install heating elements on both outer surfaces of a multilayer liquid crystal display device, but this type of display device has the disadvantage of a complicated structure. Another disadvantage of the display device with the heating element installed on the outside is that it has a large heat loss. This is because the heat generated from one side of the heating element is lost without being used to heat the display device. It is caused by This is a big problem for display devices for vehicles, where power saving is strongly desired, and there has been a demand for a liquid crystal display device that does not have this drawback.

[Purpose of invention]

The present invention has been developed in consideration of these points, and aims to provide a multilayer liquid crystal display device that does not cause thermal damage, saves power, and has good response characteristics even in low-temperature environments.

[Summary of the idea]

In the multilayer liquid crystal display device of the present invention, at least one substantially transparent planar heating element or film heating element with a large aperture ratio is installed between the liquid crystal display elements, and the thicknesses of the substrates adjacent to the heating element are not adjacent to each other. This is a multilayer liquid crystal display device characterized by being thinner than the thickness of the substrate.

[Example of idea]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 2 shows an outline of one embodiment. In FIG. 2, 21, 22, 23, and 24 are transparent substrates each having a transparent conductive film formed on its surface in a predetermined manner;
5 and 26 are transparent substrates 21, 22 and 2, respectively.
A liquid crystal layer filled with liquid crystal material between 3 and 24, 27
A first liquid crystal display element 28 having a liquid crystal material filled between both substrates 21 and 22, and a second liquid crystal display element 29 having a liquid crystal material filled between both substrates 23 and 24.
A substantially transparent planar heating element 30 is installed between the two, and 30 is an optical component such as a polarizing plate.

In the liquid crystal display element, insulating spacers 31, 32 and 33, 34 are respectively attached between the two substrates, and the thicknesses of the substrates 22 and 23 adjacent to the heating element 27 are different from those of the other substrates 21 and 23, respectively.
It is formed thinner than the

For example, the thickness of the substrates 21 and 24 is 1.1
mm, and when the thickness of the substrates 22 and 23 is 0.55 mm, the interval between the liquid crystal layers 25 and 26 is shorter than when the thickness of the substrates is 1.1 mm, and the display pattern of each liquid crystal display element is It is possible to obtain a liquid crystal display device with reduced relative positional deviation due to parallax and improved display quality. In addition, the time required for each liquid crystal layer to reach a usable temperature and be able to perform a good display as specified can be shortened by reducing the thickness of the substrate adjacent to the heating element. Display quality can be significantly improved.

In particular, good display can be achieved even when the display device is used in a low temperature environment. (1) A heating element placed outside two liquid crystal display elements (each substrate has the same thickness), (2) A heating element placed between two liquid crystal display elements (each substrate has the same thickness) (3) Comparing the results with the present invention in which a heating element is placed between two liquid crystal display elements and the thickness of the substrate adjacent to the heating element is thinner than that of the other substrates, the results are described below. . Heater power in -30℃ environment
When 100W is used, the time it takes to reach a state where the specified display can be performed is 60 seconds for (1) and 60 seconds for (2).
30 seconds, (3) is 25 seconds, and it can be seen that the display quality of the device of the present invention is good.

As the sheet heating element, a plastic film coated with indium oxide, metal thin film, etc. may be used as long as it is almost transparent, and the aperture ratio is 90%.
A metal film formed into a mesh shape can also be used.

The above has described a liquid crystal display device consisting of two liquid crystal display elements, but multilayer liquid crystal display devices consisting of three or more liquid crystal display elements can also be used in the same way, with a heating element installed inside and a substrate adjacent to the heating element. Needless to say, the same excellent effect can be obtained by reducing the thickness of the film.

[Effect of idea]

The liquid crystal display device of this invention has low power consumption and good optical response characteristics even when used in low-temperature environments.
It is an industrially useful multilayer liquid crystal display device that has excellent display quality as a liquid crystal display device and is less likely to cause thermal damage to the display device during use.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram showing an outline of a conventional liquid crystal display device, and FIG. 2 is an explanatory diagram showing an outline of a liquid crystal display device of the present invention. 21, 22, 23, 24...transparent substrate, 25,
26...Liquid crystal layer, 27...Planar heating element, 31,3
2, 33, 34...Spacer.

Claims (1)

[Scope of utility model registration request] In a liquid crystal display device comprising at least two stacked sets of liquid crystal display elements each having a liquid crystal material filled between two transparent substrates having transparent conductive films formed on their surfaces facing each other, the display element At least one substantially transparent planar heating element or a film heating element molded to a high aperture ratio is installed between the display element and the heating element, and the thickness of the substrate adjacent to the heating element in the display element is equal to the thickness of the heating element. A liquid crystal display device characterized in that the thickness of the liquid crystal display device is thinner than the thickness of a substrate not adjacent to the substrate.