JPS59116613A - Color display device - Google Patents

Abstract

PURPOSE:To form a color display which is bright and is easy to see by utilizing the layer of an optically active material having a characteristic to scatter selectively visible light of a specific wavelength. CONSTITUTION:A display body layer 2 (a layer consisting of a liquid crystal controllable of a transparent mode and a scattering mode, or a ferrodielectric transparent ceramic) is sandwiched between a transparent substrate 3 provided with segment electrodes 4 and a transparent substrate 4 provided with a counter electrode 6. A light scattering layer 7 blanked with the part facing the display segments (may be transparent) is disposed behind the layer 2 and further an optically active material layer 8 (e.g.; cholesteric polymer film) and a specular reflection plate 9 are disposed in this order behind the same, thereby forming a display panel 1. If a material which scatters selectively, for example, green light and allows the transmission of red purple light is used for the layer 8, the above-mentioned panel is capable of displaying a bright green color on the background of a white color which is slightly greenish.

Description

[Detailed description of the invention] This invention relates to a color display device.

Conventionally, a color display device in which a twisted nematic crystal and a color polarizing plate are assembled is known as a color display device. Since this display device a uses a polarizing plate, the view is reduced and becomes dark, and since there is no color polarizing plate that has a complete function, parts other than the color display part also have a ril-like color, and the appearance It had drawbacks such as low contrast. Guest-host type liquid crystal display devices are also known, but the two-color ratio of the pigments is insufficient and the contrast is low.
If the display and non-display areas are similar in color, the visual contrast is poor, and furthermore, the dyes that can be used at present are limited, so if you mix dyes to produce a variety of colors, you will not be able to produce clear colors. There were drawbacks such as.

The present invention provides a bright and easy-to-see color display device using an optically active material that has the property of selectively scattering light of a specific wavelength in the visible range.

Next, examples will be described.

In the drawings, a display layer 2 is provided on the front side of a display panel 1 of a color display device. This display layer 2 must be capable of controlling transparent mode and scattering mode. Liquid crystals and ferroelectric transparent ceramics can be used as the display layer 2.

Liquid crystals include phase-change type liquid crystals, which are p-type nematic liquid crystals mixed with chiral materials, electrothermo-optic type liquid crystals, which are p-type smectine liquid crystals mixed with chiral materials, and n-type liquid crystals.
DF with ion dopant mixed in type nematic liquid crystal
Examples include JM type, but in short, any device that can control the transparent mode and scattering mode will suffice. As a ferroelectric transparent ceramic, PLZT ceramics whose optical properties change depending on an applied voltage are known.

This display layer 2 is assumed here to be, for example, a liquid crystal.
A segment hollow 5 and a counter electrode 6 are provided to be held between the two substrates 6 and 4 and to form display segments on the opposing surfaces thereof. Professional scattering Jε; 7 is arranged on the back of this display layer 2. This light-scattering layer 7 has a +1 display body (the part facing the display segment 12 is transparent or punched. The illustration shows a case where a polyester film subjected to light-scattering treatment is used as the light-scattering layer 7. In this case, a large opening is made in the part facing the display segment.If a glass plate is used, the part facing the display segment is made transparent, and the other part is subjected to scattering treatment.

Further behind this light scattering layer 7, an optically active material layer 8 is provided. This optically active substance layer 8 selectively scatters light of a specific wavelength in the visible range, and can contain cholesteric liquid crystal, chiral nematic liquid crystal, and mixed liquid crystals, as well as optically active substances and optically active liquid crystals that do not form a liquid crystal phase by themselves. In addition to liquid crystals such as mixed liquid crystals, polymer films made of liquid crystals that exhibit cholesteric colors and can be polymerized and fixed are known as cholesteric polymer films, and may also be used. The illustration shows an example using a cholesteric polymer film, but if a liquid crystal is used, it will naturally be sandwiched between glass substrates. A specular reflection plate 9 is provided behind this optically active material layer 8 . Note that when liquid crystal is used for the optically active material layer 8, this side reflection plate may be formed by vapor deposition or the like on the glass substrates that sandwich the liquid crystal.

Currently, a method has been developed to micro-encapsulate liquid crystals, so the micro-encapsulated liquid crystals are dispersed in a transparent binder, coated on a plastic sheet coated with aluminum foil or aluminum foil, and then attached to a transparent substrate. , the optically active material layer 8 and the trowel-faced reflector 9 can be made together.

The display effect of the illustrated display panel 1 will be explained.

Assume now that the optically active substance layer 8 of the cholesteric polymer film selectively scatters green light and transmits reddish-violet light, which is its complementary color. First, when looking at part A where the display segment of the display layer 2 is in the transparent mode, incident light passes through the display layer and the optically active material layer 8 of the polymer film
The green light is selectively scattered, and the red-violet light is transmitted and reflected by the specular reflector plate 9. When the display panel 1 is stood upright and viewed from the front, the reddish-purple light is reflected diagonally downward, and this portion appears bright green. Next, looking at part B where the display segment is in scattering mode, the incident light is scattered, but is transmitted through the polymer film, green light is selectively scattered, and red-violet light is transmitted through the specular reflector. 9, and is scattered again by the display layer 2 and comes out. Here, the amount of red-violet light is smaller than that of green light due to the amount of light that travels back and forth across the polymer film. Therefore, this portion B as a whole appears to be a white scattered area with a slight green tinge. Now, in the part O where no display segment is provided, the incident light passes through the display layer 2, a part of the incident light is scattered and reflected by the light scattering layer 7, and the remaining light is reflected by the optically active material layer 8. The green light is selectively scattered, and the red-violet light is transmitted and reflected by the specular reflector 9, and then scattered again by the light scattering layer and comes out. Since the amount of light is lower for reddish-violet light than for green light, part C of and looks like white scattering with a slight green tinge, and part C of and needs to look the same as part B. , the light scattering layer 7 (d) is selected that looks the same as the part B. Because of this display effect, a voltage is applied to the display segment that is not used for display among the display segments to set it as a scattering mode. , you can display numbers, etc. by changing the display there to the same color and brightness as the background and erasing it.

In the above-described embodiment, segments can be displayed in bright green in a white scattered area with a slight green tinge. In the above embodiment, the light scattering layer 7 is provided behind the display layer 2, but it may also be placed in front of the display layer 2, and in that case, the display effect will be completely the same as in the illustrated example. It's the same.

One feature of this invention is that the portion of the light scattering layer 7 facing the display segment is transparent or has a hole. If we try to use only the scattering mode of the display layer 2 without using the light scattering layer 7, in order to display green on a white background, the entire background must be in the scattering mode.

Since the normal scattering mode is a state in which a voltage is applied from 1 to 1, this increases current consumption. However, voltage cannot be applied to the so-called gap lines between segments or around the lead wires, so when a display is made, this cap line runs on a white background, making it look like an L-sized cap line.

-1 According to the color display device of the present invention, which has a double configuration, a clear color display can be displayed on a white scattered background or a tinted white scattered background, and the contrast is good and easy to see. However, it is possible to apply voltage only to segment parts that are not necessary for display, so current consumption can be reduced.

[Brief explanation of drawings]

FIG. 1 is an explanatory cross-sectional view of an embodiment of the present invention. 2...Display layer 7...Light scattering layer 8...Optically active material layer 9, old bell reflector and above Applicant Seikosha Co., Ltd. Agent Person Patent Attorney Mogami 〒 1 account

Claims (7)

[Claims] (1) A display segment is provided between the display bodies that can control the transparent mode and scattering mode, and a light-scattering layer in which the portion of the display layer described in item 1 above facing the display segment is made transparent or punched out. A color display characterized in that an optically active material layer that selectively scatters elongated waves and long light in the visible range is provided on the back of the layer, and a λ-plane reflector is placed behind it. Device. (2) The color display device according to claim 1, wherein the dream display layer is disposed on the front side, and the light scattering layer is disposed behind it. (3) The light-scattering layer J1 is disposed in front, and behind it the display layer is disposed 1°,
1. Color display device. (4) The color display device according to claim 1, wherein the optically active material layer is made of cholesteric polymer filter. (5) The color display device according to claim 1, wherein the optically active material layer is made of Cot/Sderic G crystal. (6) The color display device according to claim 1, wherein the light scattering layer is made of a polyester film having light scattering properties, and the portion facing the display segment is punched out. (7) The color display device according to claim 1, wherein the light-scattering layer is made of glass, and the portion facing the segment is transparent, and the other portion is a light-scattering surface.