JPS62200324A - Projection type liquid crystal display device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Summary] The present invention provides a reflective projection liquid crystal display that utilizes phase transition (cholestic phase = nematic phase).
This prevents the liquid crystal layer between the picture elements from becoming scattered and unnecessary lines etc. being displayed on the projection screen. In order to prevent the display of unnecessary lines, etc., a reflective layer was formed on one substrate on the light incident side of the LCD panel in a shape corresponding to the pixel gap, so that the incident light was reflected without scattering. It is something.

[Industrial application field]

The present invention relates to a method for improving the display quality of a reflective projection liquid crystal display.

Although attempts have been made to make liquid crystal displays into big foxes, crosstalk and viewing angle limitations have made it difficult to apply them to display devices where many people can view the same screen at the same time. A 6-6 display device has been proposed that uses an element to control the on/off of light, a so-called light bulb, and enlarges and projects the I (turn) displayed on a liquid crystal panel using external light.

[Conventional technology]

FIG. 2 shows the shape of a liquid crystal panel used in a conventional reflective projection liquid crystal display that utilizes phase transition (cholesteric phase μ nematic phase), and FIG. 3 shows the overall configuration of the display device.

As shown in FIG. 2(a), the conventional liquid crystal panel 5 has a structure including glass substrates 3, 40 with parallel transparent electrodes 1.2.
Two sheets are placed one on top of the other with a spacer interposed therebetween so that each transparent electrode 1, 2 forms a single line.

FIG. 2(b) shows a plan view of a conventional liquid crystal panel.

This liquid crystal panel 5 is inserted between a reflector 6 and a Fresnel lens 7 of the display device shown in FIG. do. The display pattern of the liquid crystal panel is controlled by a drive circuit 10.

[Problem that the invention seeks to solve]

The relationship between the applied voltage and optical blockage of a liquid crystal element undergoing phase transition (cholesteric phase/nematic phase) is shown in FIG. There is a difference in light transmission blockage when the applied voltage rises and when it falls, and it has hysteresis characteristics. The pattern is displayed by holding the entry point and point B in FIG. 4 by the drive circuit 10, and selecting light scattering and light transmission of the liquid crystal element.

FIG. 5 shows an example of a conventional projection display pattern. In FIG. 5, reference numeral 11 indicates a light-scattering picture element, and reference numeral 12 indicates a light-transmitting picture element. Conventionally, as shown in FIG. 5, the surrounding area of a picture element changes from an initial transparent state to a scattered state, and a lattice pattern 14 appears. The reason for this is thought to be that a transparent electrode runs in the picture element gap 13 on either the X direction or the Y direction, and when a voltage is applied, the structure of the liquid crystal in this part becomes focal conic. Such a state cannot be controlled back to the original transparent state by the operation of the drive circuit. Therefore, an unnecessary lattice pattern is superimposed on the enlarged and projected pattern due to light scattering in the picture element gaps 13, resulting in a decrease in display quality.

[Means for solving problems]

An object of the present invention is to solve the above-mentioned conventional problems, and the object is to provide a reflection-type projection liquid crystal display that utilizes a phase transition between a breatheric phase and a nematic phase, in a shape that corresponds to the picture element gap of a liquid crystal panel. This is achieved by a projection type liquid crystal display characterized by forming a layer that reflects the incident light.

[Effect]

In the present invention, since the reflective layer is provided between the picture elements of the liquid crystal panel, the light from the light source is directly reflected without passing through the liquid crystal layer. Therefore, unnecessary grid-like patterns are not superimposed on the enlarged projection surface as in the conventional case, and display quality can be improved.

〔Example〕

Next, examples of the present invention will be described. FIG. 1 shows a plan view of a liquid crystal panel of a projection type liquid crystal display according to the present invention.

The back surface of the glass substrate 4 on the incident side of the light from the light 71918 (
On the liquid crystal layer side), as shown in Figure 1, between the picture elements of the liquid crystal panel @
The reflective layer 15 corresponding to s13 is formed in a lattice shape.

Next, an example of a manufacturing method will be explained.

First, aluminum (AJ) is formed on the glass substrate 4 by vapor deposition, and this is patterned to form a grid-like reflective N15.
leave. Next, a polyimide layer is formed on the entire surface of the lattice-shaped reflective layer 15, and a transparent electrode is formed thereon in the conventional manner. The other glass substrate 3 side is the same as the conventional one.

Note that if the reflectance of the reflective layer is close to 10 (l), a bright lattice pattern will be displayed, degrading the display quality. The display quality can be further improved by matching the occlusion.The light transmittance of a phase change type liquid crystal display is usually about 80%.In the case of a reflective type, the projected light passes through the liquid crystal panel twice. Therefore, the actual light transmittance of the projected light is approximately 64%.
becomes. This can be done by selecting the material and thickness of the metal to be deposited to form the reflective layer.

〔Effect of the invention〕

Use of the projection type liquid crystal display of the present invention has the advantage that the grid-like display pattern is removed and the display quality is significantly improved.

[Brief explanation of drawings]

Fig. 1 is a plan view of a liquid crystal panel of a projection type liquid crystal display according to an embodiment of the present invention, Fig. 2 is an explanatory diagram of a conventional liquid crystal panel, Fig. 3 is a configuration diagram of a projection type liquid crystal display, and Fig. 4 is a phase transition diagram. FIG. 5, an applied voltage-light transmittance characteristic diagram of a liquid crystal element, shows an example of a conventional projection display pattern. In the figure, 1,
2 is a transparent electrode, 3.4 is a glass substrate, 5 is a liquid crystal panel,
8 is a light source, 13 is a picture element gap, and 15 is a reflective layer. The present invention I) Mugishima Ha-Joru Heihan Old Whisper 1 a Urushi FJ > Da Saraaki Ha-Year 7 Reka Months Awake h se & womb beating applied voltage - 4 az 4 eyes picture element 12 figure ← her struggle ＼ high turn A game + 1 blur 57

Claims (1)

[Claims] 1. In a reflection type projection liquid crystal display that utilizes a phase transition between a cholesteric phase and a nematic phase, a layer that reflects incident light is formed in a shape corresponding to the gap between pixels of a liquid crystal panel. Features a projection type liquid crystal display. 2. A projection type liquid crystal display characterized in that the reflectance of the layer that reflects incident light is equal to the light transmittance that the picture elements of the liquid crystal panel exhibit in a transparent state.