JPS612130A - Liquid crystal display element - Google Patents

Abstract

PURPOSE:To hold cell gaps easily and uniformly without deteriorating display quality by forming projections for spacer integrally with a plastic film substrate and setting the number of the projection to an appropriate value. CONSTITUTION:Plural numbers of projection for specer 2 are formed integrally with a pair of plastic film subsrate 1 comprising polycarbonate, polyethylene terephthalate, etc. and having about 50-200mum thickness. The diameter of the projection 2 is regulated to 10-20mum, the height to about 6-10mum, and the number is regulated to about 50-100/mm.<2>. Transparent electrodes 4, 4 comprising In2O3, etc. are formed on the substrate 1 and a confronting substrate 3, further films treated for orientation 5, 5 are formed. Succeedingly, obtd. pair of electrode sunstrates are pasted on each other interposing a sealing material 6, and a liquid crystal material 7 is sealed to prepare the target liquid crystal display element.

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field The present invention relates to a liquid crystal display device including a plastic film substrate integrally formed with a spacer portion for maintaining a uniform cell gap.

<Prior art> Conventionally, a commonly used method for maintaining a uniform cell gap in a liquid crystal display element is to scatter or interpose glass fiber, alumina powder, etc. as a spacer between a pair of substrates over the entire surface. There was something to hold at the desired cell gap. However, in this conventional method, spacers are sprinkled and interposed on the substrate, so the desired amount of spraying (
distribution), which caused problems in process control. In addition, since the spacers are not fixed within the liquid crystal cell, the spacers move when liquid crystal is injected, and furthermore, when the liquid crystal display element is used, the spacers move, forming a group of spacers and causing a cell gap. This has the disadvantage that the alignment film becomes non-uniform or the spacer pieces damage the alignment film, resulting in poor display.

Therefore, in order to eliminate the above-mentioned drawbacks, the present invention eliminates the conventional spacer and uses a plastic film integrally formed with spacer protrusions as the substrate, thereby holding a pair of substrates with a uniform cell gap. However, if the number of the convex portions is small, non-uniformity of the cell gap will occur, and if there are many convex portions, the convex portions will become noticeable, which is not desirable in terms of display quality. When a plastic film is used as a substrate, it is extremely difficult to make the cell gap uniform because it is flexible unlike a glass substrate.

<Object of the Invention> Therefore, an object of the present invention is to provide a liquid crystal display element that does not suffer from the above problem by setting the number of the spacer convex portions to an appropriate value.

<Structure of the invention> In the present invention, the substrate has a thickness of 50 μm to 200 μm.
Films such as polycarbonate, polyethylene terephthalate, polyether sulfone, phenol resin, polyimide, polyamide, triacetyl cellulose, epoxy resin, etc., with a size of approximately μm are appropriately selected and used, and at least one of the pair of substrates is attached to these plastic film substrates. Then, roll embossing method or solvent or dry
The convex part for the spacer is integrally formed by etching method etc.
It holds a pair of substrates at a desired cell gap. In the present invention, the convex portion is approximately 50 to 100/-
It is characterized by being formed at a ratio of .

<Example> The first layer was formed on a polyethylene terephthalate or polyether sulfone substrate with a thickness of 100 μm by a roll embossing method.
As shown in the figure, convex portions 2 are formed to constitute a plastic film substrate 1 with convex portions. This convex portion has a diameter of 10 μm and a height of 9 μm, and is formed at a ratio of 50 to 100 AJ. Next, transparent electrodes containing In2O3 as a main component are provided on the substrate and the counter substrate, and after a polyimide alignment film is formed, alignment treatment is performed. A pair of electrode substrates thus obtained are bonded together via a silicone sealant, and a liquid crystal material is encapsulated therein.

FIG. 2 shows the cross-sectional structure of the liquid crystal display element formed as described above. In the figure, 1 is a plastic film substrate with a spacer projection (rear substrate), 2 is a spacer projection, 3 is a front substrate, 4 is a transparent electrode, 5 is an alignment film, and 6 is a sealing material. , 7 is a liquid crystal material.

The diameter of the spacer convex portion is 10 μm to 20 μm1.
The height is preferably about 6 μm to 10 μm, and the number is suitably formed at a ratio of about 50 to 100/-.

The reason is as follows.

FIG. 3 is a diagram showing the relationship between the uniformity of the cell gap between two electrode substrates and the number of spacer protrusions (a diagram showing experimental results). Experiments have shown that in order to maintain good uniformity of the cell gap, it is necessary to set the cell gap to about 50/- or more, and that if it is less than that, the uniformity deteriorates.

On the other hand, if the number of spacer protrusions is increased to more than about 100/-, the protrusions become visible and the quality of the display becomes extremely poor. Based on the above reasons, we The number of spacer protrusions in the invention is set within a range of about 50 to 100/-.

<Effects of the Invention> As explained in detail above, according to the present invention, process control is easy, the cell gap can be made uniform regardless of the size, and a liquid crystal display with good display quality can be produced. This makes it possible to provide a display element.

[Brief explanation of the drawing]

Figure 1 shows a plastic model with an integrally formed protrusion for a spacer.
FIG. 2 is a cross-sectional view of a film substrate, FIG. 2 is a cross-sectional view of a liquid crystal display element according to the present invention, and FIG. 3 is a diagram showing the relationship between the uniformity of cell gaps and the distribution of spacer convex portions. Explanation of the symbols 1. A plastic film substrate integrally formed with a convex portion for a spacer, 2; a convex portion for a spacer, 3: a front substrate, 4.
Transparent electrode, 5: alignment treatment film, 6° sealing material, 7° liquid crystal material.

Claims (1)

[Claims] 1. In a liquid crystal display element made of a plastic film substrate on which a convex portion for a spacer is formed, the convex portion is integrally formed with the substrate on at least one side of the substrate, and has a diameter of approximately 50 mm.
A liquid crystal display element characterized in that it is formed at a ratio of ~100/mm^2.