JPH063707A - Liquid crystal display element and reflection type liquid crystal display device and information apparatus - Google Patents

Abstract

PURPOSE:To express three display colors and to enable a bright display by varying the color tone of a first dichromatic dye dissolved into a nematic liquid crystal and the color tone of a second dichromatic dye microcapsulated in the nematic liquid crystal. CONSTITUTION:The nematic liquid crystal dissolved with the first dichromatic dye 3 is filled between a pair of substrate 1 and 2 and the nematic liquid crystal 6 contg. the microcapsulated second dichromatic dye 5 is dispersed into the nematic liquid crystal. A reflection plate is attached to the outer side of the substrate 2. The nematic liquid crystal rises at a low voltage and the color tone appearing by the decoloration of the dichromatic dye 3 is the mixed colors of the color of the dichromatic dye 5 and the color of the reflection plate when a driving voltage is impressed to the element. The color of the dichromatic dye 5 is removed and the color of the reflection plate appears when the driving voltage is further raised. The color tones mixed with the colors of the dichromatic dyes 3, 5 and the reflection plate appear when the voltage is not impressed. Then, the three color tones are expressed by controlling the driving voltage.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal display device, a reflection type liquid crystal display device and information equipment.

[0002]

2. Description of the Related Art Recently, a polymer dispersion type liquid crystal display device capable of bright display since no polarizing plate is required has been attracting attention. For example, NCAP (Nematic Curviline)
arAlined Phase) is a polymer in which microencapsulated liquid crystals are dispersed, and a black dichroic dye is further added to the microencapsulated liquid crystals to be used as a shutter. A liquid crystal display device has been devised which is combined with the reflector plate. However, in such a liquid crystal display device, there is a problem in that the color of the reflection plate or the characters and figures drawn on the reflection plate are only visible or invisible, which lacks the expressive power as a display.

[0003]

Therefore, the present invention solves such a problem, and its purpose is to
An object of the present invention is to provide a reflective liquid crystal display device that can display bright colors by displaying the displayed colors.

[0004]

A liquid crystal display device of the present invention comprises a nematic liquid crystal having a first dichroic dye dissolved between a pair of substrates on which transparent electrodes are formed. Is that the color tone of the first dichroic dye and the color tone of the second dichroic dye are different in the liquid crystal display device in which the microcapsulated nematic liquid crystal containing the second dichroic dye is dispersed. Is characterized by.

[0005]

1 is a sectional view of the structure of a liquid crystal display device of the present invention.
Shown in. In FIG. 1, a nematic liquid crystal 4 in which a first dichroic dye 3 is dissolved is filled between an upper electrode substrate 1 and a lower electrode substrate 2, and the nematic liquid crystal 4 is microcapsulated in the nematic liquid crystal. Nematic liquid crystal 6 containing dichroic dye 5 is dispersed. A white or colored reflector 7 is attached to the outside of the lower electrode substrate. When a driving voltage is applied to such a liquid crystal display device, the nematic liquid crystal 4 first stands vertically with respect to the upper and lower electrode substrates at a low voltage L, and the color of the dichroic dye 3 disappears accordingly. At this stage, the color tone of the liquid crystal display device of the present invention is a mixture of the color of the second dichroic dye 5 and the color of the reflection plate 7. When the driving voltage is further increased, the color of the dichroic dye 5 disappears at the high voltage H, and the color of the reflection plate 7 appears. When the voltage is not applied, the color tone of the dichroic dye 3, the dichroic dye 5, and the reflection plate 7 is mixed. Therefore, according to the present invention, three colors can be expressed by controlling the magnitude of the driving voltage. In the above description, both the nematic liquid crystal 4 and the nematic liquid crystal 6 have a dielectric anisotropy (hereinafter, Δ
(abbreviated as ε) is a positive liquid crystal, and Δε of the nematic liquid crystal 4 is
≧ Nematic liquid crystal 6 Δε, and dichroic dye 3
And the dichroic dye 5 are assumed to have positive dichroism. Example 1 The distance between a pair of electrode substrates was set to 12 μm, and the maximum absorption wavelength of 650 nm was set as the first dichroic dye 3 in the liquid crystal of Δε = 10 as the nematic liquid crystal 4 therebetween.
This blue dichroic dye is dissolved at a concentration of 1.0 wt%, and as the second dichroic dye 5, a yellow dichroic dye 6 having a maximum absorption wavelength of 450 nm is dissolved in the blue liquid crystal at a concentration of 1%. What was dissolved in the nematic liquid crystal 6 having Δε = 10 at 0.0 wt% was dispersed. The particle size of the microcapsules is about 7 μm, and the addition rate of the microcapsules is 50 wt% with respect to the nematic liquid crystal 4. Further, a white reflector is attached to such a liquid crystal display element to form a liquid crystal display device. The voltage-transmittance curve of this example is shown in FIG. 2. From 0V to 3V, green that is a mixture of blue and yellow is exhibited, from 4.5V to 8V, yellow is exhibited, and from 12V and above, white is exhibited.

[Embodiment 2] The distance between a pair of electrode substrates is set to 1
The nematic liquid crystal 4 is set to Δε during the period of 5 μm.
= 10, a blue dichroic dye having a maximum absorption wavelength of 670 nm was dissolved as a first dichroic dye 3 at a concentration of 2.0 wt%, and microcapsules were dissolved in the blue liquid crystal.
As the second dichroic dye 5, a red-purple dichroic dye 6 having a maximum absorption wavelength of 550 nm was dissolved in a nematic liquid crystal 6 having Δε = 13 at a concentration of 1.5 wt% and dispersed. The particle size of the microcapsules is about 6 μm, and the addition rate of the microcapsules is 60 w with respect to the nematic liquid crystal 4.
t%. Further, a yellow reflector is attached to such a liquid crystal display element to form a liquid crystal display device. The voltage-transmittance curve of this example is shown in FIG. 3. From 0V to 4V, a black color with a mixture of blue, magenta and yellow is shown, and from 6V to 10V, an orange color with a mixture of magenta and yellow. To
15V or more is yellow.

[Third Embodiment] A dashboard to be mounted on an automobile was prepared by using the reflective liquid crystal display devices of the first and second embodiments. That is, the pattern as shown in FIG. 4 is formed by the reflective liquid crystal display device according to the present invention, and the voltage of 17V is applied to the display portion 8 of the speedometer by applying the second embodiment at a speed of less than 100 km. Yellow was displayed, and orange was displayed by applying a voltage of 7 V at a speed of 100 km or more. When there is no abnormality in the display unit 9 of the water thermometer by applying the first embodiment, it is 2
Green was displayed by applying a voltage of V, and white was displayed by applying a voltage of 17 V when the water temperature was abnormal. Next, by applying the second embodiment to the display section 10 of the tachometer, yellow is displayed by applying a voltage of 17V at less than 7,000 rpm, and orange is displayed by applying a voltage of 7V at 7,000 rpm or more. Displayed colors. Reference numeral 11 denotes a decorative plate which hides unnecessary portions other than the display portion and draws fixed characters by printing or the like.
Although this embodiment is premised on the use of a reflection type, if auxiliary lighting is required at night or the like, the light source 12 may be installed on the side surface or the back surface of the present liquid crystal display device for lighting.

[0008]

As described above, according to the present invention, since a polarizing plate is unnecessary, a bright display is possible, so that it is suitable for use in a reflection type display, and a three-color display can be easily performed by changing a driving voltage. There is an effect that a liquid crystal display device capable of expressing colors can be provided.

[Brief description of drawings]

FIG. 1 is a diagram showing a structure of a liquid crystal display device of the present invention.

FIG. 2 is a diagram showing a voltage-transmittance relationship of a liquid crystal display device of the present invention.

FIG. 3 is a diagram showing a voltage-transmittance relationship of the liquid crystal display device of the present invention.

FIG. 4 is a diagram showing an embodiment of the present invention.

[Explanation of symbols]

 1. Upper electrode substrate 2. Lower electrode substrate 3. First dichroic dye 4. Nematic liquid crystal 5. Second dichroic dye 6. Nematic liquid crystal 7. Reflector 8. Display of speedometer 9. Display of water temperature gauge 10. Display of tachometer 11. Veneer 12. light source

Claims (5)

[Claims] 1. A nematic liquid crystal in which a first dichroic dye is dissolved is filled between a pair of substrates on which transparent electrodes are formed,
In the liquid crystal display element in which the nematic liquid crystal containing the second dichroic dye-encapsulated microcapsule is dispersed in the nematic liquid crystal, the tone of the first dichroic dye and the tone of the second dichroic dye are A liquid crystal display device characterized by different. 2. A reflection type liquid crystal display device comprising a liquid crystal display device according to claim 1 and a white reflector attached thereto. 3. A reflective liquid crystal display device comprising a liquid crystal display element according to claim 1 and a colored reflector plate attached thereto. 4. An information device comprising the reflective liquid crystal display device according to claim 2. 5. An information device comprising the reflective liquid crystal display device according to claim 3.