JPS6220863Y2 - - Google Patents

Description

[Detailed explanation of the invention] This invention uses an external force such as a voltage or current to illuminate a light-receiving display element, which can perform display by absorbing, scattering, or rotating external light, with a luminous body that emits colored light. The present invention relates to a color display device that can easily display multiple colors.

Conventionally, liquid crystal is filled between opposing electrodes, a voltage is applied between the opposing electrodes selected according to the pattern to be displayed, and light is emitted from a light source on the back side to display multiple pattern parts. There is a liquid crystal display device that does this (see, for example, Japanese Utility Model Application Publication No. 122077/1983). In this prior art, a light source is provided inside a light source block covered with a reflector to prevent the diverging light of the light source from leaking outside the light source block, thereby increasing the effective amount of light. Efforts are being made to improve contrast.

However, in the above-mentioned prior art, since a plurality of pattern parts are irradiated with one light source, a plurality of pattern parts are always illuminated. Therefore, since light is irradiated even in the dark field area where some light is transmitted, there is a problem in that the contrast of the bright field pattern area is reduced accordingly.

By the way, while the above-mentioned prior art is a monochrome display, in recent years there are liquid crystal display devices that can change the display color appropriately by irradiating the patterned portion with multicolored light sources (for example, −
(See Publication No. 42468). Although this prior art has one pattern portion, it is conceivable to provide a plurality of pattern portions and simultaneously irradiate each pattern portion with a different color. However, if a light source is simply provided for each pattern portion, the light from the light sources of different colors will interfere with each other, resulting in a problem that the color contrast will deteriorate.

This invention was made in view of the above two problems, and aims to provide a color display device that can improve color and brightness contrast.

In order to achieve the above purpose, this idea first
By providing a reflective film for each light source block body in which a color light emitting element is embedded, and by providing a plurality of pattern parts, and by making the light source block body provided with the above reflective film correspond to each of these pattern parts, The color contrast is improved by preventing the different colored lights irradiated onto the plurality of pattern parts from interfering with each other. moreover,
This idea connects the light emitting elements of each light source block to the power source through independent switches, and uses the ON/OFF operation of this switch and the action of the reflective film provided for each light source block. ,
By illuminating only the bright field pattern area, i.e.
By not irradiating the dark-field pattern portions that allow some light to pass through, the contrast between light and dark is improved.

Hereinafter, detailed embodiments of this invention will be explained with reference to the drawings. FIG. 1 is a sectional view showing an embodiment of this invention. In the figure, 10 is a liquid crystal element, 20, 30
indicates a light source block body. FIG. 2 is a sketch showing the structure of the light source block body 20. As shown in FIG.

In FIG. 1, a liquid crystal element 10 has transparent electrodes 2a and 2b made of thin films such as In ₂ O ₃ and SnO ₂ placed on transparent substrates 1 a and 1 b such as glass, and these transparent electrodes 2 a and 2 b A nematic liquid crystal 4 is injected with a spacer 3 in between so that the long axes of the liquid crystal molecules are parallel to the planes of the transparent electrodes 2a and 2b and twisted by 90 degrees between the electrodes, and such a liquid crystal cell is made. , two polarizing plates (paranicol) 5a, 5 whose polarization directions are parallel to each other and coincide with the long axis or short axis of the liquid crystal molecules on the transparent electrodes 2a, 2b.
b has a sandwiched structure.

When light enters the liquid crystal element 10, the light passes through the polarizing plate (polarizer) 5a on the incident light side, passes through the liquid crystal cell, and then passes through the polarizing plate (analyzer) 5b on the light exit side.
, and a dark field (opaque state) is obtained. In this state, when a predetermined voltage is applied to the liquid crystal layer 4 from the power supply 6 through the lead wire 7, the liquid crystal molecules are rearranged so that their long axes are perpendicular to the surfaces of the transparent electrodes 2a and 2b, and the incident light is transmitted to the analyzer 5b. bright field (transparent state) is obtained. Therefore, if the transparent electrodes 2a and 2b are shaped into characters, symbols, or pictures to be displayed, various patterns can be displayed.

The light source blocks 20 and 30 each have a plurality of light emitting diodes of different colors formed into small blocks in order to obtain a plurality of luminescent colors, and as shown in FIG.
The display pattern portions 21 and 31 are provided in close contact with each other on the back side of the display pattern portions 21 and 31, and have a structure in which only the display pattern portions 21 and 31 are illuminated.

FIG. 2 shows an example of the structure of the light source block body 20, in which a red light emitting diode 15a is placed inside a block 14 made of transparent epoxy resin or silicone resin.
An orange light emitting diode 15b and a green light emitting diode 15c are embedded. The resin block 14 is provided with a metal reflective film 16 by vapor deposition or plating on all surfaces other than the surface in contact with the liquid crystal element 10, so that light emission can effectively cover the display pattern parts 21, 3 of the liquid crystal element.
It has a structure that irradiates 1. In this embodiment, the light source block 30 has exactly the same structure as the light source block 20 .

The transparent electrodes 2a and 2b of the liquid crystal element 10 are patterned, for example, by chemical etching, to form portions to which a voltage is applied to the liquid crystal layer 4 and portions to which no voltage is applied.
When a voltage is applied to the liquid crystal layer 4 from the power source 6 and power is supplied from the power source 8 through the lead wires 9a, 9b, 9c, and 9d to light up the light emitting diode 15a, 15b, or 15c contained in the resin block 14, the liquid crystal element The pattern portions 21, 31 to which a voltage of 10 is applied are illuminated with light from a light emitting diode.

Switch 11a or 11b or 11c
By blinking each light emitting diode appropriately using
31 can be seen in red, orange or green. The pattern portions 21 and 31 of the liquid crystal element 10 to which no voltage is applied are dark fields.

Similarly to the light source block body 20 , the light source block body 30 also has lead wires 10a, 10b, 10 connected to the power source 8.
Power is supplied to the included light emitting diodes through terminals c and 10d, and selection and blinking can be performed by switching the switches 12a, 12b and 12c.

FIG. 3 shows an example of a display by the display device of this invention.

The display pattern parts 21 and 31 are "7" shaped like "〓".
It uses a liquid crystal display element that displays numbers in segments, and the figure shows a state in which two digits "1" and "2" are displayed. The parts "1" and "2" are in a transparent state, and the light source blocks 20 and 30 provided on the back side of the parts are used to display a red light emitting diode for "1" and a green light emitting diode for "2". The selection is lit. As a result, "1" is displayed in red and "2" is displayed in green.

Various color displays can be made by changing the light emitting diodes to be lit in accordance with the changes in the number display pattern portions 21 and 31.

In the above configuration, the present invention provides that the light source blocks 20 and 30 have separate display pattern portions 21 and 30, respectively.
31, and each light source block body 20, 3
The area around 0 is covered with a reflective film 16. For this reason, each pattern portion 21, 31 is illuminated only by the corresponding light source block 20 , 30 , that is, by the other light source blocks 20, 30.
30, there is no risk of being illuminated by two lights of different colors. Therefore,
Since different colored lights do not interfere with each other, high color contrast can be obtained in each pattern portion 21, 31.

Incidentally, the liquid crystal layer 4 shown in FIG. 1 allows some light to pass through even in an opaque state, that is, in a dark field. Therefore, if there is a bright field pattern portion 21 and a dark field pattern portion 31, all pattern portions 2
When 1 and 31 are illuminated, light also passes through the dark field, so it is conceivable that the brightness contrast of the bright field pattern portion 31 in the entire liquid crystal element 10 is reduced.

On the other hand, in this invention, for example, when only the number "2" is displayed, that is, when the pattern portion 21 on the left side is in the dark field, while the pattern portion 31 on the right side is in the bright field, the switch 9a,
9b and 9c are turned off, and the dark field pattern portion 21 is not illuminated. Therefore, only the bright field pattern portion 31 is the light source block body 30.
Since the liquid crystal element 10 is illuminated by , the brightness contrast of the portion "2" in the entire liquid crystal element 10 is improved.

If the display pattern portions 21 and 31 have a larger area than the light emitting diode, the display pattern will be uneven, which is not preferable. In this case, a scattering plate may be inserted between the polarizing plate 5a and the light source block 20 or 30 , or the number of light emitting diodes may be increased to increase the lighting area. Further, by installing a parabolic mirror and arranging a light emitting diode at its focal point, it is possible to make parallel emitted light beams enter the liquid crystal element 10, and the above-mentioned uneven lighting can be improved. Further, in the above embodiment, the two polarizing plates 5a and 5b were set to parallel Nicols, but the pattern portions 21 and 31 can be displayed in color even if they are set to crossed Nicols. Only the colored pattern parts are reversed.

In the above embodiment, three types of light emitting diodes are used as the light emitters to enable three color display, but the number of displayed colors can be increased by increasing the number of types of light emitting diodes. Furthermore, it is clear that similar effects can be obtained by using not only a light emitting diode but also a light bulb, a fluorescent display tube, a plasma panel, an electroluminescence panel, or a Nixie tube as the light emitting body.

In the above-mentioned embodiment, a liquid crystal layer was provided in the light-receiving element and its twisted nematic mode was used, but a similar multicolor display can also be achieved by using a dynamic scattering mode. In addition to liquid crystal elements, transparent dielectric ceramics such as PLZT can be used as the light-receiving element, and the same multicolor display can be achieved by utilizing the scattering or birefringence mode of the transparent dielectric ceramics. An electrochromic panel may also be used.

As described above, according to this invention, it is possible to improve color and brightness contrast in a color display device that displays a plurality of pattern portions in color.

[Brief explanation of the drawing]

Fig. 1 is a sectional view showing an embodiment of the display device of this invention, Fig. 2 is a sketch showing the structure of a light source block body used in this invention, and Fig. 3 is a sectional view showing an embodiment of the display device of this invention. FIG. In the figure, 10...liquid crystal element, 1a, 1b...
...Transparent substrate, 2a, 2b...Transparent electrode, 3...Spacer, 4...Liquid crystal layer, 5a, 5b...Polarizing plate,
6... Power source for supplying voltage to be applied to the liquid crystal layer 4, 7a, 7b... Lead wires, 20 , 30 ...
Light source block body, 21, 31...pattern part,
8...Power source for supplying power to the light source block body, 9a, 9b, 9c, 10a, 10b, 10c
...Lead wires, 11a, 11b, 11c, 12
a, 12b, 12c...Switch, 13...Observer, 14...Resin block, 15a, 15b, 1
5c...Red, orange, and green light emitting diodes, respectively, 16...Metal reflective film. In addition, in the figures, the same reference numerals indicate the same or corresponding parts.

Claims (1)

[Scope of utility model registration request] First and second transparent electrode groups are disposed to face each other with a material whose transmittance to light changes depending on an electric field or current, and have a plurality of pattern portions in which patterns are displayed depending on the shape of the electrodes. A light-receiving display element, and a plurality of color light-emitting elements of different colors are embedded in each pattern part on the back side of the pattern part of this light-receiving display element, and each is connected to a power supply via an independent switch. a transparent resin light source block body connected to the light-receiving type display element to irradiate the light-receiving type display element, and having a surface other than the light irradiation direction to the light-receiving type display element coated with a metal reflective film; A color display device characterized in that a light emitting element in a light source block is selectively turned on in accordance with a change in transmittance of a type display element to light, thereby illuminating a desired display pattern portion for color display.