JPS5945991B2 - exiyouhiyoujisouchi - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a liquid crystal display device in which a reflective plate has directionality.

In general, a liquid crystal display device is constructed by arranging a liquid crystal between two electrode substrates, at least one of which is transparent, and applying a voltage to part or all of the liquid crystal in accordance with the pattern to be displayed. The pattern is displayed.

Since this liquid crystal display device has low power consumption and low voltage drive performance compared to other display devices, it is widely used for displaying electronic desktop calculators, digital wristwatches, and the like. FIG. 1 is a cross-sectional view showing an example of a conventional liquid crystal display device, and in the figure, 1a and Ib are an upper substrate and a lower substrate made of transparent insulating substrates arranged facing each other.

On the opposing surfaces of the upper substrate 1a and the lower substrate Ib, an upper electrode 2a and a lower electrode 2b in a predetermined pattern are formed using transparent conductive films. Further, the interval between the upper substrate 20 plate 1a and the lower substrate Ib is maintained at a predetermined dimension, and the periphery thereof is sealed with sealing materials 3a and 3b to form an outer atmosphere 4. A liquid crystal 5 is sealed inside the envelope 4 through a sealing opening (not shown).
Further, polarizing plates 6a and 6b whose polarization axes intersect are attached to the outer surfaces of the substrate 1a and the lower substrate 25 plate Ib, respectively. Further, a light guide T is arranged on the outer surface of this polarizing plate 6b. The light guide T is made of transparent glass, and its surface, that is, the surface on the polarizing plate 6b side, forms a light diffusing surface Ta that is roughly processed into a 30-sided shape, and the back surface thereof is made of aluminum. A vapor deposited film is applied to form a reflective surface 7b. The light diffusing surface Ta is processed by a combination of mechanical polishing such as sandblasting and chemical etching, and has both a transmitting function 35 and a diffusing function. Further, a lamp 8 for nighttime display is arranged on the end face portion of the light guide T, thereby configuring a liquid crystal display device. In the liquid crystal display device configured in this way, the polarized light that has passed through the polarizing plate 6a is transmitted to the upper substrate 1a1 and the upper electrode 2a.
The light is transmitted through the liquid crystal 2, rotated by 9', and then transmitted through the lower electrode 2b, the lower substrate 1b1, and the polarizing plate 6b, and further transmitted through the light diffusing surface 7a1 and the transparent light guide 7 to the reflective surface 7b.
is incident on the Then, the incident light wave is reflected at a reflection angle corresponding to the incident angle, and is transferred to the transparent light guide 7, the light diffusion surface 7a1, the polarizing plate 6b1, the lower substrate 1b1, the lower electrode 2b, the liquid crystal 5, the upper electrode 2a1, the upper substrate 1a1, the polarizing plate 6a. It faces the viewer through the lens, and the entire surface is uniformly bright. Next, the upper electrode 2a
When selecting the lower electrode 2b and applying a voltage between them,
Since the liquid crystal in the area to which the electric field is applied loses its optical rotation, the light incident on this area cannot pass through the polarizing plate 6b, and only the area to which the electric field is applied becomes dark and the desired pattern is displayed. will be done. Next, if the surroundings are dark,
For example, at night when there is no surrounding lighting, the display cannot be read because there is no external light incident on the polarizing plate 6a. For this purpose, a lamp 8 disposed close to the light guide 7 in the liquid crystal display device is turned on by a switch (not shown).
By uniformly diffusing the light source of the lamp 8 by the light diffusing surface 7a, a desired pattern can be displayed as a transmission type liquid crystal display device in the same manner as described above. However, in the conventional liquid crystal display device with the above configuration, since the reflector is non-directional, when the direction of the external light and the observation direction are almost the same, the display pattern becomes difficult to see, or in extreme cases. It has the disadvantage that it becomes completely invisible.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a liquid crystal display device that displays patterns with directivity. In order to achieve such an object, the liquid crystal display device according to the present invention provides a reflective surface of a reflective plate with directivity.

The liquid crystal display device according to the present invention will be explained in detail below using the drawings. FIG. 2 is a cross-sectional view for explaining one embodiment of the liquid crystal display device according to the present invention, and the same symbols as in FIG. 1 represent elements, so the explanation thereof will be omitted.

In the figure, a transparent glass light guide 9 is disposed on the outer surface of the polarizing plate 6b, and a lamp 8 is disposed close to the end face of the light guide 9. The surface of this light guide 9 has a light diffusing surface 9a that is roughened to have a transmitting effect and a diffusing effect, as in the case described above. In addition, a light reflecting plate 10 having directivity that reflects both the light from the lamp 8 and the external light only in a predetermined direction is adhered to the back surface of the light guide 9 with a transparent adhesive 11. has been done. This directional reflector 10 can be easily obtained by, for example, oblique vapor deposition, unidirectional polishing, or the like. For example, in order to give a reflector directivity by polishing, there are two directions: one polishing direction that produces a predetermined reflection directivity for external light, and the other polishing direction that produces a predetermined reflection directivity for light from a lamp. Polishing may be repeated in two different directions. In the liquid crystal display device configured in this way, when an electric field is applied between the upper electrode 2a and the lower electrode 2b in a desired pattern, the liquid crystal in the area where the electric field is applied loses its optical rotation effect. External light that has passed through the polarizing plate 6a and entering the portion is blocked by the polarizing plate 6b.

Therefore, only the portion to which the electric field is applied becomes dark, and the desired pattern is displayed. In this case, since the light reflecting plate 10 has directivity in its reflection direction as described above, it reflects more light only in a specific direction. Therefore, by setting the orientation direction of the light reflecting plate 10 to the viewing direction of the observer, it becomes extremely easy to read the displayed pattern. This is particularly advantageous for electronic desktop calculators, wristwatches, etc., since the viewing direction thereof is almost specified. Also,
By lowering the light diffusivity of the light diffusing surface 9a and increasing the transparency of the light guide 9, the incidence and reflection efficiency of the light reflecting plate 10 is increased, and external light in the daytime is further reduced close to the end face of the light guide 9. The light from the lamps 8 arranged in the same direction is also reflected with directionality in the direction of the observer's field of vision, so even the light source of the lamps 8 at night can be displayed with uniform brightness, so it can be used day or night. The display becomes extremely clear and easy to read. In addition, in the above-mentioned embodiment, a case was explained in which a light reflecting surface made of aluminum was used for the light reflecting plate to give directionality to the reflected light, but the present invention is not limited to this, and other It goes without saying that the same effect can be obtained even if the light reflecting surface is formed of metal.

In the above embodiment, a case has been described in which the polarization directions of the two polarizing plates are crossed, but it goes without saying that the same effect can be obtained even if they are made to match.

As explained above, the liquid crystal display device according to the present invention is a reflective device that directionally reflects both the light from the lamp disposed close to the end face of the light guide and the external light in the viewing direction of the viewer. Since it has a plate, a desired pattern is displayed within a predetermined viewing angle, and the display can be easily and instantaneously confirmed.

Furthermore, by giving the reflected light a predetermined directivity, it has various superior effects such as making it easier to see patterns compared to conventional liquid crystal display devices.

[Brief explanation of drawings]

Figure 1 is a cross-sectional view showing an example of a conventional liquid crystal display device;
The figure is a sectional view showing an embodiment of a liquid crystal display device according to the present invention. 1a... Upper substrate, 1b... Lower substrate, 2a... Upper electrode, 2b... Lower electrode, 3a, 3b...・Sealing material. 4...
Envelope, 5...Liquid crystal, 6a, 6b...
Polarizing plate, 7... Light guide, 7a... Light diffusing surface, 7b... Reflecting surface, 8... Lamp, 9a... - Light diffusion surface, 10...Reflector, 11...Adhesive.

Claims (1)

[Claims] 1 Insulating substrates facing each other, electrodes formed on opposite surfaces of the edge substrates, a liquid crystal sealed between both the insulating substrates, and a liquid crystal disposed on one outer surface side of the insulating substrates, a light guide having a light diffusing surface on the side thereof; a lamp disposed close to the end face of the light guide; and a lamp disposed on the outer surface of the light guide to protect an observer from light from the lamp and external light. 1. A liquid crystal display device comprising: a reflector plate having a reflective characteristic that is directional in a viewing direction.