JPS61203424A - Tn-fem liquid crystal display element - Google Patents

Abstract

PURPOSE:To increase response speed by forming a TN-FEM liquid crystal display element constituted of a pair of substrates to a prescribed cell thickness and forming transparent conductive film electrodes on the substrates to 1-3mum thickness thereby decreasing the thickness of the liquid crystal layer on the electrodes. CONSTITUTION:Films consisting of an indium-tin alloy (IT) are deposited to 1.5mum thickness onto the glass substrates 1, 1' by a sputtering method using said the IT. The films on the glass substrates 1, 1' are then patterned by photoetching. The patterned films are calcined by which the indium tin oxide (ITO) electrodes 2, 2' having 1.5mum thickness are obtd. Oriented films 3, 3' are formed thereon by using polyimide and subjecting the same to an orientation treatment. The cell is formed of the substrates 1, 1' and a seal 4 and a liquid crystal 5 is sealed therein. Polarizing plates 6, 6' are adhered to the outside of the substrates 1, 1. The cell thickness 7 between the electrodes 2, 2' is thereby decreased and the rising time and falling time of the liquid crystal display element are reduced, by which the response speed is increased.

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Object of the Invention [Field of Industrial Application] The present invention relates to a liquid crystal display element, and particularly to the structure of its transparent conductive film electrode.

[Conventional technology]

In conventional liquid crystal display elements, transparent conductive film electrodes are formed on glass substrates by sputtering and electron beam methods to a thickness of about 150 to 2,000 layers.

[Problem that the invention seeks to solve]

In conventional liquid crystal display elements, the sheet resistance of transparent conductive film electrodes is several hundred to several tens of ohms/sq, and there is a problem in that high-duty driving causes a voltage drop, resulting in a decrease in contrast. In addition, there was a demand for a reduction in response speed.

(B) Structure of the Invention The structure of the invention is such that the thickness of the transparent conductive film electrode on this substrate is 1 to 1 in the cell thickness of a cell configured between a pair of substrates.
The cell structure shown in Fig. 1 is adopted in which the cell thickness on the electrode is reduced to 3 μm, and in this case, the degree of brightness and darkness when the display section is on and off, which can be obtained with a conventional transparent conductive film electrode with a thickness of 150 to 2000, is In other words, by ensuring the contrast ratio and the steepness of the rise characteristic of the voltage-transmittance curve in the optical characteristics of the liquid crystal display element shown by the arrow in Fig. 3, that is, the γ value of the formula below, The TN is characterized by having no abnormality in environmental tests, shortening the rise time, interval and fall time of the response speed, and causing no voltage drop even during high-duty driving, thereby preventing a decrease in contrast. -FEM liquid crystal display element.

〔Example〕

The present invention will be described in detail below based on the embodiments shown in FIGS. 1 and 2, but the present invention is not limited thereby.

FIG. 1 shows the structure of a liquid crystal display element (100) of the present invention.

An alloy of indium and tin (IT) is deposited on a glass substrate (11 (1')) to a thickness of 1 by sputtering.
．． A 5 μm IT-based film is deposited.

At this time, this film has a film quality close to that of an IT film.

The above glass substrate (11
(1”) Patterning is performed to obtain the required pattern of electrodes from the IT-based film provided on the top.Here,
Since this IT-based film has a film quality similar to that of an IT film, it is extremely easily dissolved in an acidic aqueous solution and can be easily etched.

The patterned film was fired, and an ITo electrode (2
) (2°) is obtained. , 1m (7) I To electrode (2)
(2') has sufficient light transmittance and electrical conductivity as before.

The substrate (1) (
Alignment films (3) (3') are formed on (1').

After that, a cell is formed with the substrates (1) (1') and the seal (4), and a cyclohexane-based liquid crystal (5), for example, is filled in the cell, and then a liquid crystal injection hole (not shown) is filled. Close. In order to prevent the interference phenomenon of light, the interference phenomenon of the ITO electrode shown in Fig. 2, and the color tone difference of the liquid crystal layer due to the difference in cell thickness, we need to develop a property that can cancel this out in the visible range. The obtained polarizing plate (6) (6'') is attached to the outside of the glass substrate 111 (1'').

Here, the liquid crystal display element (100) is completed.

This liquid crystal display element (100) is manufactured as described above. Therefore, the sheet resistance of the transparent conductive film electrode, ie, the To electrode, is 1 Ω/sq or less, and even if this liquid crystal display element is used in high-duty driving, there is no reduction in contrast due to electrode resistance. In addition, since the ITO electrode (21 (2') is thick, the cell thickness on the ITO electrode (
7) In other words, the thickness of the liquid crystal layer is substantially thinner. Incidentally, the rise time τr and the fall time τd, which are the response speeds of the electro-optical phenomenon of the liquid crystal display element, satisfy the following relationship.

That is, τr CX: d ” r d oc d ” [where τr: rise time, τd: fall time, d: cell thickness, liquid crystal layer thickness], n: = 2°]. Therefore, in the liquid crystal display element of the present invention, the value of the cell thickness (7) on the ITO electrode is small, and the rise time τr and fall time τd are small. That is, the values are 18 m5ec and 29m5ec, respectively. Incidentally, in the conventional example, they were 34 isec and 33 m5ec, respectively.

Of course, the liquid crystal display element of the present invention has γ, which is the steepness of the rising characteristic of the voltage-transmittance curve in the optical characteristics of the liquid crystal display element.
The value and the contrast ratio, which is an index of the degree of brightness and darkness when the display is on and off, are at the same level as conventional ones, and it has also withstood reliability tests (environmental tests) and has no problems in use. An example of these characteristic values is summarized in Table 1 below.

(The following margins continue on the next page) Table 1 (c) Effects of the invention This invention does not cause a decrease in contrast even when driven at high duty, and also improves the rise time and fall time of electro-optical phenomena. We provide small liquid crystal display elements.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram showing an embodiment of the present invention, FIG. 2 is a diagram explaining the relationship between the wavelength of light and the transmittance of an ITO electrode according to the present invention, and FIG. FIG. 3 is a diagram illustrating the relationship between voltage and transmittance in optical characteristics. (100) One liquid crystal display element, (old glass substrate, (2) --ITO electrode, (
3) - alignment film, (4) - seal, (5) - liquid crystal, (6) - polarizing plate, (7) - cell thickness on ITO (thickness of liquid crystal layer). Figure 1 Required Figure 2 (Transparent length (nm)) Figure 3 (t/E/y)

Claims (1)

[Claims] 1. In a TN-FEM liquid crystal display element composed of a pair of substrates, the cell thickness is a predetermined thickness, and the transparent conductive film electrode on this substrate is formed to have a thickness of 1 to 3 μm, and the liquid crystal layer on this electrode is formed. A TN-FEM liquid crystal display element characterized by having a reduced thickness, thereby ensuring various electro-optical characteristics and reliability, and improving response speed and contrast reduction.