JPH02101426A - Production of liquid crystal display element - Google Patents

Abstract

PURPOSE:To make curved surface display with good display quality by using a curved base having a prescribed sectional shape and successively sticking upper and lower polarizing plates while a liquid crystal cell on the curved base is held curved alone. CONSTITUTION:The upper polarizing plate 8 and the lower polarizing plate 9 are successively stuck to the surface of the liquid crystal cell 1 while the liquid crystal 1 formed of a flexible film substrate is held cured on the curved base 10 having a prescribed sectional shape. Generation of a change in the cell gap is, therefore, obviated at the time of sticking the polarizing plates. The curved display which does not impair the display quality in terms of brightness, visual angle characteristic, floating feel of display picture elements, etc., is executed in this way.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a method for manufacturing a liquid crystal display element including a liquid crystal cell using a flexible film substrate.

Conventional technology Conventionally, this type of liquid crystal display element was of the TN type (twisted type).
The mainstream is one using a nematic type (nematic type) liquid crystal cell. This means that there is a distance between the two substrates with transparent display electrodes.
It is composed of a liquid crystal cell provided with a liquid crystal layer having a 0' spiral structure, and a pair of upper and lower polarizing plates disposed to sandwich this liquid crystal cell.

However, this TN type has a limit in display capacity.

Therefore, when considering the recent increase in the size of dot matrix type liquid crystal display elements, this is insufficient.

Therefore, recently, instead of such a TN type,
A liquid crystal display element using a mode display method called SBE or STN in which the twist angle is 180° or more has been proposed and has already been put into practical use.

Here, in the display system of the mode called SBE or STN, Δn・d (however, Δ
n"n6 n, ne: refractive index in the long axis direction of liquid crystal molecules, nt: refractive index in the short axis direction of liquid crystal molecules, d: cell gap - for coloring by slight changes in the thickness of the liquid crystal layer , if there is a partial change in the gap d within the cell, color unevenness will occur.

For this reason, in this type of liquid crystal cell, polished glass plates or the like, whose cell gap can be easily controlled, are used as the pair of upper and lower substrates. However, in recent years, flexible film substrates such as polyester and polyether sulfon with a film thickness of about 100 μm have been used as liquid crystal cell substrates in order to make liquid crystal display devices thinner and lighter, easier to process, and lower in cost. It is attracting attention for its use. In addition, a pair of polarizing plates arranged to sandwich the liquid crystal cell usually has a polarizing plate of 100 to
A film-like material with a thickness of about 200 μm is used. In addition, by using a flexible circuit board made of polyimide or a thin glass evo board as the drive circuit board connected to the liquid crystal cell, it is possible to make the liquid crystal display device flexible as a whole, and the seal of the liquid crystal cell It is also possible to display curved surfaces as long as the strength and gap uniformity can be maintained.

Problems to be Solved by the Invention In such a liquid crystal display element, it is desirable to attach the polarizing plates to both sides of the liquid crystal cell from the viewpoint of brightness, viewing angle characteristics, floating feeling of display pixels, etc. However, it is difficult to bend a liquid crystal display element to which a polarizing plate is directly attached due to its thickness and rigidity when handling polarized light.
If you try to bend it forcibly, stress will be applied to the flexible film substrate of the liquid crystal cell to which the polarizing plate is attached, resulting in unevenness. Therefore, color unevenness occurs due to cell gap changes peculiar to liquid crystal display elements made of flexible film substrates.

Means for Solving the Problem A liquid crystal cell is provided in which a liquid crystal is sandwiched between a pair of flexible film substrates that have transparent electrodes for display and are aligned, and an upper polarizing plate and a lower polarizing plate are placed above and below this liquid crystal cell. Alternatively, in a method for manufacturing a liquid crystal display element in which a lower polarizing plate with a reflective plate is provided, the liquid crystal cell is curved on a curved table having a predetermined cross-sectional shape to form an upper polarizing plate and a lower polarizing plate or a lower polarizing plate with a reflective plate. The plates are sequentially bonded to the surface of the liquid crystal cell.

Function: When a liquid crystal cell made of a flexible film substrate is left alone in a curved state and polarizing plates are placed in contact with both its upper and lower surfaces, the liquid crystal cell will display a curved surface even if the cell is curved to a cross-sectional shape of approximately 150 mm. It is possible. However, simply arranging a polarizing plate causes problems such as brightness, viewing angle characteristics, and a floating feeling of display pixels due to the interface between the liquid crystal cell and the polarizing plate.

Therefore, by using a curved table with a predetermined cross-sectional shape and bonding the upper and lower polarizing plates in order with the liquid crystal cell curved independently on this curved table, we improved the brightness, viewing angle characteristics, floating feeling, etc. A liquid crystal display element capable of displaying a curved surface with good display quality without any problems can be obtained.

Example An embodiment of the present invention will be described based on the drawings.

First, a liquid crystal cell l having a structure as shown in FIG. 2 is prepared. This liquid crystal cell 1 has a thickness of 100 μm and has transparent display electrodes 3a and 3b (one becomes a common electrode and the other becomes a segment electrode, facing each other in a matrix shape) on which alignment films 2a and 2b are formed and subjected to alignment treatment. A pair of flexible film substrates 4a and 4b are provided, and a liquid crystal 7 is sandwiched between these flexible film substrates 4a and 4b by sealing with a sealing material 6 while maintaining a uniform interval with a gap material 5. Become. A liquid crystal cell with this structure alone has a radius of curvature of 10
Even when curved to about 0 mm, color unevenness due to cell gap change did not occur.

A pair of upper polarizing plates 8 are provided on both the upper and lower surfaces of such a liquid crystal cell 1.
and a lower polarizing plate with a reflector (a simple lower polarizing plate may also be used)
A liquid crystal display element is manufactured by bonding the convex curved table 10.9 as shown in FIG. It is manufactured using a concave curved table 11. First, as shown in FIG. 1(a), the liquid crystal cell 1 manufactured as shown in FIG. Place it alone on suction hole 1.
By adsorbing it onto the curved surface 10a through 0b, the liquid crystal cell 1 is suction-fixed in a curved cross-sectional shape of 150 mm (of course, the liquid crystal cell 1 may be fixed by a method other than suction).

A lower polarizing plate 9 with a reflector is arranged on the liquid crystal cell 1, and the lower polarizing plate 9 is sequentially pressed along the curved shape of the surface of the liquid crystal cell 1 by the rotational movement of the roller 12 while being brought into pressure contact. Paste them together.

After the pasting of one polarizing plate 9 is completed, the liquid crystal cell 1 with this polarizing plate 9 is turned over and placed on a concave curved table 11 having a curved surface 11a with a cross-sectional shape of 150 mm as shown in FIG. 1(b). to be installed. Then, the liquid crystal cell 1 (
(on the polarizing plate 9 side) is suctioned and fixed onto the concave curved table 11. Here, the curved surface table 10°11 has the same cross-sectional shape as the curved surface 10a, ll
Since the concavity and convexity are reversed, there is no new bending deformation in this adsorbed state. Then, as in the case of FIG. 1(a), the upper polarizing plate 8 is placed on the liquid crystal cell 1, and the upper polarizing plate 8 is sequentially shaped into a concave curved shape on the surface of the liquid crystal cell 1 by rotational movement of the roller 13. Paste them together by pressing them together and applying pressure.

By going through the steps shown in FIGS. 1(a) and 1(b), the bonding of the pair of polarizing plates 8 and 9 to the liquid crystal cell 1 is completed, and by removing them from the concave curved table 11, the structure shown in FIG. 3 is completed. As shown, a completed liquid crystal display element 14 is obtained. The liquid crystal display element 14 curved in this manner returns to a flat cross-sectional shape of approximately 200 mm due to the flexibility of the flexible film substrates 4a, 4b and the polarizing plates 8, 9, but due to external fixing and packaging processing, Radius of curvature 130~150mu+
Even when the cell was bent to a certain extent, color unevenness due to cell gap changes did not occur. Therefore, a curved display element with good display quality can be obtained.

In addition, the flexible film substrates 4a and 4b and the polarizing plates 8 and 9
Preferably, both are soft and thin.

In this embodiment, 1 is used as the flexible film substrates 4a and 4b.
004m polyether sulfon film, polarizing plate 8
. In addition, in this embodiment, first, the lower polarizing plate 9 with a reflector is bonded together using the convex curved table 10, and then the upper polarizing plate 8 is bonded together on the concave curved table 11. The order of use of to and 11 and the attachment of polarizing plates 8 and 9 may be reversed.

In addition, the curved table 10.11 of this embodiment has a cross-sectional shape of 150 m.
m, but one having a predetermined curvature is used depending on the material, thickness, etc. of the flexible film substrate and polarizing plate in the liquid crystal display element to be manufactured.

In addition, if the convex curved table 10 and the concave curved table 11 have opposite concave and convex shapes, a shape that partially has a predetermined radius of curvature or a shape whose curvature changes, etc. By using a curved table, various curved display elements can be produced.

Furthermore, although the liquid crystal display element of this example is an example of a dot matrix type that uses an STN or SBE mode display method, it can be applied to any liquid crystal display element in which the liquid crystal cell is formed of a flexible film substrate. .

Effects of the Invention As described above, the present invention focuses on the fact that when a liquid crystal cell formed from a flexible film substrate is curved alone, the display quality of the curved surface is not impaired, and the present invention provides a curved surface having a predetermined cross-sectional shape. The upper polarizing plate and the lower polarizing plate or the lower polarizing plate with a reflector were laminated to the surface of the liquid crystal cell in order with the liquid crystal cell in a curved state on the table, so that changes in the cell gap were avoided when the polarizing plates were laminated. It is possible to obtain a liquid crystal display element capable of displaying a curved surface, which prevents the occurrence of color unevenness, and does not impair display quality in terms of brightness, viewing angle characteristics, floating wind of display pixels, etc.

[Brief explanation of the drawing]

The drawings show one embodiment of the present invention, and FIG. 1 (a) and (b) are schematic front views showing the polarizing plate bonding process in order, FIG. 2 is a cross-sectional structural diagram of a liquid crystal cell alone, and FIG. 3 is a manufacturing process. FIG. 3 is a cross-sectional structural diagram of a subsequent liquid crystal display element. 1... Liquid crystal cell, 3a, 3b... Transparent electrode for display,
4a, 4b...Flexible film substrate, 7...Liquid crystal,
8... Upper polarizing plate, 9... Lower polarizing plate with reflective plate or lower polarizing plate, 10. li...Curved table diagram

Claims (1)

[Claims] A liquid crystal cell is provided in which a liquid crystal is sandwiched between a pair of flexible film substrates that have transparent electrodes for display and have been subjected to alignment treatment, and an upper polarizing plate and a lower polarizing plate or a lower polarizing plate with a reflector are provided above and below this liquid crystal cell. In a method of manufacturing a liquid crystal display element, the liquid crystal cell is curved on a curved table having a predetermined cross-sectional shape, and an upper polarizing plate and a lower polarizing plate or a lower polarizing plate with a reflector are sequentially attached to the surface of the liquid crystal cell. 1. A method for manufacturing a liquid crystal display element, which comprises bonding the element to a liquid crystal display element.