JPS61256304A - Liquid crystal color display device - Google Patents

Abstract

PURPOSE:To obtain a clear color display by using mainly a specific quinacridone pigment as a red coloring material of the color filter. CONSTITUTION:The titled device is provided the liquid crystal element capable of controlling a transmission-shield of an electromagnetic wave according to an image information and the color filter of picture element shaped, thereby enabling to observe the transmitted light of the liquid crystal through the color filter. The quinacridone pigment shown by formula is mainly used to the red- colored coloring material of the color filter. The preferable quinacridone pigment is the compd. of the formula wherein X1 and X2 are each hydrogen, chlorine or bromine atom, methyl group or S atom. Said pigment has preferable spectral characteristics for the red coloring material of the red filter of the title device, and does not extend a half-width wavelength range to the wavelength of the green light, thereby effectively preventing to produce the mixed color.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a liquid crystal color display device using a liquid crystal element as an optical switching element.

Color display devices that apply liquid crystal elements have been attracting attention in recent years because they can be made thinner. p, 2
11-240''.

Among liquid crystal color display devices, those using a liquid crystal element as a light shutter are expected.

In this method, pixel color filters of three primary colors, R2O and B, are arranged corresponding to the pixel electrodes of a liquid crystal element, and the light transmitted through the color filters is observed by illuminating with a backside light source.

Color filters used in such devices are required to have high transmittance and clear colors. Furthermore, if the transmission spectrum of a filter of another color overlaps, color mixing occurs and the color tone deteriorates. Therefore, in order to display a clear color image, it is necessary to prevent the half-widths from overlapping with the transmission spectra of filters of other colors.

Conventionally, color filters have been formed into strips, mosaics, etc. by dyeing casein, gelatin, polyvinyl alcohol, synthetic proteins, or photoresists. In addition, dyes have also been formed by electrodeposition on electrodes.

However, these methods have limitations in the selection of dyes and have not been able to achieve sufficient color display.

SUMMARY OF THE INVENTION The object of the present invention is to realize clear color display in a liquid crystal color display device.

The liquid crystal color display device of the present invention includes a liquid crystal element that controls the transmission/blocking of electromagnetic waves according to image information, and a pixel-shaped color filter, and the liquid crystal color display device of the present invention has a pixel-shaped color filter that controls the transmitted light of the liquid crystal element. A liquid crystal color display device for viewing through a color filter is characterized in that a quinacridone pigment represented by general formula (I) is mainly used as a red coloring material of the color filter.

II H (In the formula, X represents hydrogen or a substituent.) The present invention will be explained in more detail below.

FIG. 1 is a sectional view schematically showing an embodiment of the present invention. a first substrate 15 with transparent electrodes 11, 13 respectively;
and a second substrate 17 are arranged to face each other, and this substrate 15
．． A TN type liquid crystal cell 21 is formed by sealing a TN type liquid crystal substance between the cells 17 and 17 . 19 indicates a sealing material. The liquid crystal cell 21 has a polarizing plate 23 on the viewing side and a polarizing plate 25 on the back side.
A 90°-TN type liquid crystal element 31 is sandwiched between the two. This liquid crystal element can control transmission and blocking of light from the light source 41 by applying a signal voltage between the electrodes 11 and 13, and functions as a light switching element. The light source 41 includes a phosphor layer 43 and an ultraviolet lamp 45 as an energy source. 47 is a substrate holding a phosphor layer.

A color filter 3 on the pixel is provided on the outer surface of the second substrate 17.
3 is formed. The color filter 33 includes an R pixel filter 33a that selectively transmits red light, a G pixel filter 33b that selectively transmits green light, and a B pixel filter 33c that selectively transmits blue light. Each pixel filter 33a.

By observing the transmitted light of 33b and 33c using the liquid crystal element 31 as a light shutter, full-color II
! An image is displayed.

As the main coloring material of the R pixel filter 33a, a quinacridone pigment represented by the general formula (I) is used.

Particularly preferred quinacridone pigments are those in which X□lX2 is hydrogen, chlorine, bromine, a methyl group, or S in general formula (I).

The quinacridone pigment of the present invention has spectral characteristics suitable as a coloring material for red filters in liquid crystal color display devices, and also has a wavelength range at half maximum that does not extend to the green wavelength region, making color mixing effective. It can be prevented. - As an example, the spectral transmission spectrum of a filter in which a quinacridone pigment in which Xl and x2 are both hydrogen in the general formula (A) is dispersed in a resin binder and applied to a thickness of about 3 μm is shown as TR in Figure 2. .

The color filter 33 can be formed by dispersing pigment in a resin binder and patterning it by a printing method such as screen printing or a photoetching method using a photoresist. Pigment has an average particle size of 2μ
It is preferable to use fine particles of less than m. The appropriate thickness of the color filter is about 1 to 5 μm, preferably 1-5 μm.
~5 μm. In addition, each color fill can use multiple coloring materials to cut unnecessary wavelengths or control color tone.

The coloring materials used for the G pixel filter 33b and the B pixel filter 33c are appropriately selected so that the half widths of the respective transmission spectra do not overlap, and examples thereof include phthalocyanine blue and phthalocyanine green. Preferred B and G pixel filter-like pigments include:
Examples include phthalocyanine pigments represented by the following general formulas (II), (m), or (IV).

(In the formula, Y,, Y2.Y3.Y, represents ci or Br, and nzt n2+ nay n< represents 1 to 4.) (Hereinafter, the margin is blank) 17= (1. in the formula, Z,, Z, , Z3.Z, t*C1 is shown, Tnz p ]n27 m3 y Jn4 is 1~
4 is shown. ) (In the formula, Ys=Ys-Y?-Ys represents H or =8-COONa.) In the general formula (II), X is C1, and spectroscopy of a phthalocyanine pigment containing 15 to 16 of these in total The transmission spectrum is shown in Figure 3.

In FIG. 1, the phosphor layer 43 can be formed by dispersing and coating phosphor particles that emit light in R, G, and B in a binder. Further, the phosphor can be formed in the shape of R, G, and B pixels corresponding to each of the R2O and B pixel filter sections.

The light emitted from the phosphor is additively mixed by a color filter, and a brighter and better color image can be obtained. Here, the relationship between the emission spectrum of the phosphor and the transmission spectrum of the color filter is important, but the quinacridone red pigment of the present invention has a transmission spectrum suitable as a coloring material for the R filter, so it can be used for good color display. It can be realized. FIG. 2 shows an example of the phosphor emission spectrum as ER.

The position of the color filter is not limited to that shown in FIG. 1; for example, it can be formed on the transparent electrode, on the first substrate surface, or on the polarizing plate 25 or on another separate substrate. It can also be provided in

The main feature of the present invention is to use a quinacridone-based red pigment in a color filter of a liquid crystal color display device, and other components may be selected as appropriate. For example, the light source is electroluminescence (EL).
) A light emitter, a fluorescent lamp, a white lamp, etc. can be used, and as for the liquid crystal element, any liquid crystal element can be used as long as it functions as a light shutter, such as a guest-host type.

According to the present invention, by using a quinacridone red pigment represented by the general formula (I) as a red coloring material of a color filter in a liquid crystal color display device, a clear color image display can be realized.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing an actual IO-embodiment of the liquid crystal color display device of the present invention. FIG. 2 is a graph showing an example of the spectral transmission spectrum of the quinacridone red pigment used in the present invention and the emission spectrum of the phosphor. FIG. 3 is a graph showing the spectral transmission spectrum of a green pigment. 11.13... Transparent electrode I5... First substrate 1
7... Second substrate 21... Liquid crystal cell 31...
・Liquid crystal element 33...color filter 4】...
・Light source 43...Phosphor layer 45...Ultraviolet lamp Patent applicant Ricoh Co., Ltd. 10 Procedural amendment June 27, 1985 Manabu Shiga, Commissioner of the Patent Office 1, Indication of case 1985 Patent application No. 98046 2, Name of the invention LCD color display device 3, Relationship with the amended person case Patent applicant 1-3-6 Nakamagome, Ota-ku, Tokyo (674) Ricoh Co., Ltd. Representative Hama 1) Hiroshi 4. Agent 5, Ichibancho Phoenix Building, 15-1 Ichibancho, Chiyoda-ku, Tokyo, Subject of amendment (I) "Invention Ichimon Kihon jJ column -+%' 6, Contents of amendment" (I) Insert "or Br" after "C1" on page 8, line 2 of the specification. I"2

Claims (1)

[Claims] 1. It has a liquid crystal element that controls transmission/blocking of electromagnetic waves according to image information and a pixel-shaped color filter, and the light transmitted through the liquid crystal element is observed through the color filter. In the liquid crystal color display device, the red coloring material of the color filter is mainly represented by the general formula (I)▲mathematical formula, chemical formula, table, etc.▼(I) (wherein, X_1 and X_2 are hydrogen or a substituent ) A liquid crystal color display device characterized by using a quinacridone pigment represented by: