JPS59139021A - liquid crystal display device - Google Patents

Abstract

PURPOSE:To improve display quality by disposing a neutral polarizer on the outside surface of a liquid crystal display element with the absorption axis made parallel therewith, and disposing a polarizer having the absorption axis intersecting orthogonally with said absorption axis, a display pattern and a light source on the one outside surface thereof. CONSTITUTION:The light radiated from a light source 11 is polarized by a multicolor polarizer 10 and is made incident to a neutral grey polarizer 9. Since the absorption axis of the polarizer 10 intersects orthogonally with the absorption axis a2 of the polarizer 9, only the light of the wavelength region showing a specific color is made incident to a liquid crystal display element 1 and the other light cannot be transmitted through the polarizer 10. The same holds true of the case in which the driving voltage is not impressed between electrodes 3a and 3b. If the driving voltage is impressed between the upper and lower electrodes 3a and 3b in contrast with the above-mentioned case, the optical rotatory power of a liquid crystal 4 is lost between 3a and 3b and the light transmitted through the liquid crystal 4 is transmitted through the polarizer 6a as it is and only the character A of the color polarizer 10 of a negative-printed two- layered polarizing plate 8 is displayed in a red color on the black ground by an electrode pattern. As a result, the display pattern having high contrast is obtd.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to a liquid crystal display device that performs multi-color display using transmitted light using a native nematic type (hereinafter referred to as TN) liquid crystal display element.

[Prior art]

Conventionally, in this type of liquid crystal display device, in order to display a color pattern using transmitted light on a black background consisting of the light shielding part of the TN liquid crystal display element, a neutral polarizing plate is placed on the outer surface of the electrode substrate of the TN liquid crystal display element, and the polarizing plate is Generally, a method is used in which a color filter cut out in the shape of a desired display pattern is adhered and placed on the back side polarizing plate, which is the surface opposite to the display surface of the TN liquid crystal display element whose axes are arranged parallel to each other. Ta.

However, with such a configuration, since the color filter is formed by coating a dye on a support, it is difficult to obtain an optically large dichroic ratio. In addition, in terms of appearance, when dividing one display surface to display different colors, it is necessary to arrange color filters of multiple colors, and with such a configuration, the filter shape of each color is different. There was a drawback that the color pattern was too conspicuous and the appearance shape of the color pattern was impaired. In addition, in order to prevent the external shape of each color filter from being too conspicuous, it is possible to reduce the transmittance of neutral polarizing plates arranged in parallel. In a liquid crystal display device, if a polarizing plate with reduced transmittance is used, the display of the color pattern will become cloudy and the display quality will deteriorate. Therefore, it is not possible to reduce the transmittance of the polarizing plate, and therefore It was impossible to prevent the external shape from becoming too conspicuous. In other words, there was a drawback that a color pattern display with high display quality could not be obtained.

[Purpose of the invention]

Therefore, the present invention has been made in view of the above-mentioned situation, and an object of the present invention is to provide a liquid crystal display device that can provide a color display pattern with high display quality.

[Summary of the invention]

In order to achieve such an object, the liquid crystal display device according to the present invention has a neutral polarizer arranged on the outer surface of the liquid crystal display element with absorption axes parallel to each other, and an absorption axis arranged on one outer surface of the neutral polarizer. A neutral polarizer, a multicolor display pattern, and a light source are arranged.

[Embodiments of the invention]

Next, embodiments of the present invention will be described in detail using the drawings.

FIG. 1 is a cross-sectional configuration diagram of essential parts showing an example of a liquid crystal display element according to the present invention. In the figure, reference numeral 1 has translucent upper and lower electrodes 3a and 3b on the entire opposing surfaces of translucent upper and lower electrode substrates 2a and 2b arranged oppositely, and both electrode substrates 2a and 2
A liquid crystal display element is constructed of a TN liquid crystal 4 sealed between b and its peripheral part sealed with a sealant 5, and 6 is a transparent adhesive on the observer side surface of the liquid crystal display element 1, that is, on the electrode substrate 2a. Neutral gray polarizer 8 is adhesively arranged through adhesive 7, neutral gray polarized light 39 is adhesively arranged on the back surface of liquid crystal display element 1, that is, lower electrode substrate 2b through transparent adhesive I, and color display pattern. 11 is a light source arranged on the back side of the liquid crystal display element 1, and 12 is an observer who observes the display surface of the liquid crystal display element 1. in this case,
The neutral gray polarizer 6 on the display surface side is formed by adsorbing iodine to polyvinyl alcohol (PVA) and stretching it, and one side is reinforced with a support made of translucent acrylic resin, and the other side is reinforced with a support made of translucent acrylic resin. A translucent adhesive 7 is adhered to the surface side. In addition, as shown in an enlarged cross-sectional view in FIG. 2, the two-layer polarizing plate 8 includes a neutral gray polarizer 9 having the same structure as the neutral gray polarizer 6 on the display surface side, and a red dye adsorbed on PVA. A multicolor polarizer 10 in which a printed layer 13 of a color display pattern is provided by negatively printing a black dye as each color dye on the background excluding the letter A on a multicolor polarizer stretched by
and a neutral gray polarizer9. Supports 14 and 15 made of a transparent acrylic resin for supporting the polarizer are arranged on the outer surface of the multicolor polarizer 10 and are laminated via an adhesive γ. A pressure-sensitive adhesive I is attached to the liquid crystal display element 1 (see FIG. 1).

Further, FIG. 3 is an exploded view of essential parts for explaining the principle of the liquid crystal display device according to the present invention shown in FIGS. 1 and 2, and the same symbols in the figures indicate the same parts. In the same figure, a liquid crystal display element l
The absorption axis al of the neutral gray polarizer 6 disposed on the display surface side and the absorption axis a2 of the neutral gray polarizer 9 constituting the two-layer polarizer 8 disposed on the back side thereof.
are arranged so as to be parallel to each other, and the absorption axis a8 of multicolor polarized light ÷10 is arranged so as to be orthogonal to each other.

In the liquid crystal display device configured in this way, the light source 11
The light emitted from the is polarized by a multicolor polarizer 10 with a negative printed display pattern, and then enters a neutral gray polarizer 9. absorption axis a
8 are almost perpendicular to each other, among the incident polarized light waves, only light in a wavelength range showing a specific color determined by the optical characteristics of the color polarizer 10 enters the liquid crystal display element 1, and only light in the other wavelength ranges enters the liquid crystal display element 1. The light cannot pass through the color polarizer 1o and is blocked. Thus force 2 - polarizer 10
When the light transmitted through the neutral gray polarizer 9, for example, red light, is transmitted through the liquid crystal display element 1, the portions of the upper and lower electrodes 3a and 3b (see FIG. 1) of the liquid crystal display element 1 that do not have an electrode pattern , this light is rotated 90 degrees by the liquid crystal layer, whereas the absorption axis a8 of the neutral gray polarizer 10 is almost parallel to the absorption axis al of the neutral gray polarizer 6 on the viewing surface side, so this neutral gray It cannot pass through the polarizer 6 and is blocked. This corresponds to the electrodes 3a and 3b of the liquid crystal display element 1 (
The same applies to the case where no driving voltage is applied to the portion provided with the electrode pattern (see FIG. 1). On choosing against this.

When a driving voltage is applied between the lower electrodes 3a and 3b, the optical rotation of the liquid crystal 4 (see Figure 1) is lost between the electrodes 3a and 3b, so that the light transmitted through the liquid crystal 4 remains neutral. The light passes through the gray polarizer 6, and only the letter A of the color polarizer 10 of the two-layer polarizing plate 8, which is negatively printed, is displayed in red on a black background due to the electrode pattern.

In addition, in the above-mentioned embodiment, the case where the printed layer 13 with the multi-color double pattern was provided on the outer surface of the neutral polarizer disposed on the outermost surface was explained, but the present invention is not limited to this. Even if a color filter printed or printed on a support is placed on the upper back surface of the liquid crystal display element 1, that is, on the outer surface of the lower electrode substrate 2a, on the inner and outer surfaces of the neutral gray polarizer 9, or on the inner surface of the neutral polarizer, the same effect as described above will not occur. Of course, similar effects can be obtained. In this case, the color filter printed on the support is, for example, according to the example, the letter A has a printed pattern by red dyeing, the background has a printed pattern by black dye, and the polarizer disposed on the outermost surface has no printed pattern at all. Only neutral polarizers with absorption axes orthogonal to each other are arranged.

Further, in the above-mentioned embodiment, a case was explained in which red was used on a black background as the color tone of the color polarizer 10, but the present invention is not limited to this, and in addition to red, for example, blue, Yellow, orange.

Of course, by using a warm color tone such as green, a color display pattern with high contrast can be obtained.

Further, in the above-mentioned embodiment, a case was explained in which only one type of letter A was used as the pattern of the color polarizer 10, but the present invention is not limited to this.
It goes without saying that a color display pattern with high contrast can be obtained even if a plurality of patterns of different color tones are formed in combination.

〔Effect of the invention〕

As explained above, according to the liquid crystal display device according to the present invention, a color display pattern with high contrast can be obtained, so that an extremely excellent effect of significantly improving display quality can be obtained.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional configuration diagram of essential parts showing an example of a liquid crystal display device according to the present invention, FIG. 2 is an enlarged cross-sectional view of the two-layer polarizing plate shown in FIG. 1, and FIG. 3 is a developed explanatory diagram of FIG. 1. is. 1...Liquid crystal display element, 2a...Upper electrode substrate, 2b...Lower electrode substrate, 3a...Upper electrode, 3b...Lower electrode, 4...TN liquid crystal ,5
... Seal agent, 6 ... Neutral gray polarized light 1, T ... Adhesive, 8 ... Two-layer polarizing plate, 9 ...
...neutral gray polarizer, 10...multicolor polarizer, 11...light source, 12...observer,
13...Printing layer, 14.15...Support. Figure 1 Cough ν12 Figure 2 Figure 3

Claims (1)

[Scope of Claims] 1. A liquid crystal display in which a transparent electrode is formed on the entire surface of the opposing surfaces of two transparent substrates arranged opposite each other, and a twisted nematic type liquid crystal is sealed between the opposing substrates. element, and a first. a second neutral polarizer, and a third polarized light disposed on the outer surface of one of the first and second neutral polarizers with the absorption axis orthogonal to the first and second neutral polarizers. a multicolor display pattern disposed between an outer surface of the liquid crystal display element and an outer surface of the third neutral polarizer; and a light source disposed on the outer surface of the third neutral polarizer. 2. The liquid crystal display device according to claim 1, wherein a multicolor display pattern is provided by negative printing on the third neutral polarizer.