JPH04277719A - Liquid crystal display element - 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]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an adhesive elliptically polarizing plate that is used by adhering to a liquid crystal display device or the like.

0002

[Prior Art] A conventional adhesive elliptically polarizing plate used by adhering to an LCD (liquid crystal display panel) of a simple matrix type or TFT type liquid crystal display device includes, for example, a protective film, a polarizing plate, and at least one retardation plate. It is constructed by laminating a plate and a release film.

FIG. 3 is a partial cross-sectional view of an example of a conventional adhesive elliptically polarizing plate.

9 is a protective film having optically biaxial characteristics, 2 is a polarizing plate, 3 is a polarizer, 4a, 4b are supports for the polarizer, 5a, 5b, 5c are adhesives, 6a, 6b are The retardation plate 10 is a release film having optical biaxial characteristics.

[0005] Techniques using such polarizing plates include, for example, the Technical Report of the Television Society, I.T.
E.J. Technical Report Volume 12, Number 32, pp. 29-34, I.D.'88-75, 1
August 988 (ITEJ Technical Rep
ort Vol. 12 No. 32, pp. 29-34
, ID'88-75 (Aug, 1988)).

[0006]

[Problems to be Solved by the Invention] However, since both the protective film 9 and the release film 10 attached to the top and bottom of the conventional adhesive elliptically polarizing plate 8 have biaxial optical characteristics, it is difficult to remove both films. Glue the adhesive elliptically polarizing plate 8 to the LCD.
Unless it was mounted, it was not possible to inspect the polarization degree unevenness of the polarizing plate 2 and the phase difference unevenness of the retardation plates 6a and 6b. That is, conventionally, when the adhesive elliptically polarizing plate 8 is attached with both films 9 and 10, interference colors occur and photoelastic inspection cannot be performed.

Therefore, if an optical defect is detected on the adhesive elliptically polarizing plate 8, the adhesive elliptically polarizing plate 8 is peeled off.
A new adhesive elliptically polarizing plate had to be reattached, resulting in low productivity.

[0008] The object of the present invention is to use an adhesive elliptically polarizing plate in an LCD.
An object of the present invention is to provide an adhesive elliptically polarizing plate that can be inspected for polarization degree unevenness and retardation unevenness before being adhered to.

[0009]

[Means for Solving the Problems] In order to solve the above problems, the adhesive elliptically polarizing plate of the present invention has a protective film, a polarizing plate, at least one retardation plate, and a release film laminated. The adhesive elliptically polarizing plate is characterized in that the protective film and the release film each have an optically non-axial property.

0010

[Function] In the adhesive elliptically polarizing plate of the present invention, since the protective film and the release film each have an optically non-axial characteristic, the degree of polarization is uneven when the protective film and the release film are attached to the adhesive elliptically polarizing plate. and phase difference unevenness can be inspected.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a partial sectional view of an embodiment of the adhesive elliptically polarizing plate of the present invention.

1 is a protective film having an optically non-axial characteristic; 2 is a polarizing plate; 3 is a polarizer; 4a, 4b are supports for the polarizer; 5a, 5b, 5c are adhesives; 6a, 6b are The retardation plate 7 is a release film having an optically non-axial characteristic.

The protective film 1 is provided to prevent the upper surface of the polarizing plate 2, that is, the upper surface of the support 4a, from getting dirty or scratched when the adhesive elliptically polarizing plate is handled. It is attached to the top. The release film 7 is provided to protect the adhesive 5c used to attach the adhesive elliptically polarizing plate to an LCD (not shown), and is peeled off when the adhesive elliptically polarizing plate is attached to the LCD.

To explain each layer in more detail, the material of the protective film 1 is, for example, polyethylene, and the thickness is about 70 mm.
The thickness of the polarizing plate 2 is about 190 μm, and the polarizer 3 is made by dyeing polyvinyl acetate (PVA) with iodine (I2). The material of the supports 4a and 4b is triacetylcellulose (T
AC). The polarizing plate 2 is made by stretching a stack of a support 4a, a polarizer 3, and a support 4b. Adhesive 5a, 5
The thickness of b and 5c is about 25 μm, the material of the retardation plates 6a and 6b is polycarbonate (PC), and the thickness is about 50 μm.
Optically, it has uniaxial characteristics. The release film 7 is made by coating a polyester (PET) film with silica (Si). The total thickness of the adhesive elliptically polarizing plate 8 is approximately 37
It is 0 μm. The protective film 1 and the release film 7 are made by pouring them into molds and shaping them, so that they have an optically non-axial property. In addition to the above-mentioned polyethylene and polyester, acrylic, polystyrene, triacetyl cellulose (TAC), polyester sulfone, etc. can be used as the material for both films.

In the adhesive elliptically polarizing plate 8 of this embodiment, since the protective film 1 and the release film 7 each have an optically non-axial characteristic, both films are peeled off and the adhesive elliptically polarizing plate is adhered and mounted on the LCD. Even if you do not do this, it is possible to inspect uneven polarization degree and uneven phase difference with both films attached to an adhesive elliptically polarizing plate. Therefore, it is not necessary to reattach the adhesive elliptically polarizing plate as in the past, and the productivity of the LCD can be improved. To inspect uneven polarization and phase difference, place two ideal polarizing plates with no uneven polarization so that their absorption axes are at right angles, place an adhesive elliptical polarizer between them, and measure the polarization. The presence or absence of power unevenness and phase difference unevenness is photoelastically inspected with the naked eye.

FIG. 2 is an exploded perspective view showing a liquid crystal display device using the adhesive elliptically polarizing plate 8 according to the present invention.

11 is a liquid crystal cell, 11a is an upper electrode substrate,
11b is the lower electrode substrate, 25 is the liquid crystal alignment direction of the upper electrode substrate 11a, 26 is the liquid crystal alignment direction of the lower electrode substrate 11b, 12 is the upper polarizing plate, 21 is the absorption axis of the upper polarizing plate 12,
13 is a second retardation plate; 22 is an optical axis of the second retardation plate 13;
14 is a first retardation plate; 23 is an optical axis of the first retardation plate 14;
15 is a lower polarizing plate, 24 is an absorption axis of the lower polarizing plate 15, 1
6 is a light diffusing material, and 17 is a backlight.

Light emitted from the backlight 17 enters the liquid crystal cell 11 via the light diffusing material 16 and the lower polarizing plate 15. Further, the light passes through a first retardation plate 14 and a second retardation plate 13 for color compensation, and finally exits from the upper polarizing plate 12. A voltage is applied between the upper electrode substrate 11a and the lower electrode substrate 11b to select the optically rotating part and the non-optically rotating part in the liquid crystal cell 11 to perform a predetermined display. It goes without saying that the present invention is also applicable to a liquid crystal display element in which the incident direction and the outgoing direction of light are reversed in FIG. 2.

Although the present invention has been specifically explained above based on the above embodiments, the present invention is not limited to the above embodiments, and it goes without saying that various modifications can be made without departing from the gist thereof. be.

[0020]

[Effects of the Invention] As explained above, in the present invention,
Since the adhesive elliptically polarizing plate can be inspected for polarization degree unevenness and phase difference unevenness with the protective film and release film attached to the adhesive elliptically polarizing plate, the productivity of LCD can be improved.

[Brief explanation of the drawing]

FIG. 1 is a partial cross-sectional view of an embodiment of the adhesive elliptically polarizing plate of the present invention.

FIG. 2 is an exploded perspective view of a liquid crystal display device showing an example in which the adhesive elliptically polarizing plate according to the present invention is applied to the liquid crystal display device.

FIG. 3 is a partial cross-sectional view of an example of a conventional adhesive elliptically polarizing plate.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1... Protective film with optically non-axis characteristics, 2... Polarizing plate, 3... Polarizer, 4a, 4b... Support for polarizer, 5a,
5b, 5c...Adhesive, 6a, 6b...Retardation plate, 7...Release film with optically non-axis characteristics, 8...Adhesive elliptically polarizing plate, 11...Liquid crystal cell, 11a...Upper electrode substrate, 11b …
Lower plate electrode substrate, 12... Upper plate polarizing plate, 13... Second retardation plate, 14... First retardation plate, 15... Lower plate polarizing plate, 16... Light diffusing material, 17... Backlight, 21... Upper plate Absorption axis of polarizing plate, 22... Optical axis of second retardation plate, 23... Optical axis of first retardation plate, 24... Absorption axis of lower plate polarizing plate, 25... Liquid crystal alignment direction of upper plate electrode substrate, 26 ...Liquid crystal alignment direction on the lower electrode substrate.

Claims (1)

[Claims] Claim 1: A protective film, a polarizing plate, and at least one
An adhesive elliptically polarizing plate formed by laminating two retardation plates and a release film, wherein the protective film and the release film each have an optically non-axial property. The liquid crystal display element used.