JPS58159519A - Manufacture of liquid crystal display device - Google Patents

Abstract

PURPOSE:To obtain a liq. crystal display device with enhanced durability and reliability, by irradiating far ultraviolet rays having a specified wavelength or below on orienting films on the surfaces of glass substrates at the peripheral sealing parts to enhance the tightly sealing performance of a sealing resin. CONSTITUTION:Far ultraviolet rays having <=250nm wavelengths are irradiated on a liq. crystal orienting agent on the surfaces of a pair of opposite glass substrates at the peripheral sealing parts to which a sealing resin is stuck. The lamp of an ultraviolet irradiator to be used is an ozone genertion type lamp emitting light having <=about 200nm wavelengths, and a conventional ozoneless type lamp which is used in the ultraviolet curing of resin, etc. is not effective. When ultraviolet rays are irradiated, it is required to use a mask corresponding to a liq. crystal display pattern on the glass substrate and to mask the parts where the orienting films are allowed to remain.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing a positive color liquid crystal display device of the Guest-Hos type.

Conventionally, in manufacturing a guest-host type positive color liquid crystal display device, a transparent electrode film is formed on two opposing glass substrates, and a 5102 insulating film is further applied thereon. After coating, in order to vertically align the liquid crystal with respect to the substrate, a method is used in which the liquid crystal is rubbed, treated with an organic silane coupling agent, and then heated and dried to form an alignment film.

In such a manufacturing method, the treatment with an organosilane-based carbonate soaking agent has conventionally been carried out using a dipping method, which is suitable for mass production and provides a high-quality coating.

In this method, an alignment film is formed on the entire surface of the glass substrate, but since the surface of this alignment film has a low energy surface chemically, it adheres to the sealing area around the glass substrate surface. A problem arises in that the applied sealing resin is susceptible to measles and its adhesion and sealing properties are significantly reduced. Therefore, in the sealing area on the pair of glass substrates, this alignment coating must be removed, or the concentration of the organic silane coupling agent that makes up the coating must be low enough not to impair the performance of the sealing resin. is desirable.

The entire purpose of the present invention is to provide a method of manufacturing a liquid crystal display device that eliminates such conventional problems.

It is thought that the organic silane coupling agent used as the alignment agent exists on the glass substrate in a state as shown in FIG. In addition, in FIG. 1, 1 is a glass substrate, and R is an alkyl group.

Conventionally, a plasma ashing method has been used to remove such an organic alignment film.
This requires low pressure conditions, which is not favorable for mass production.

The inventors believe that this compound has a short wavelength (25 onm or less)
It has been discovered that the metal has the property of completely absorbing ultraviolet rays and is decomposed by ultraviolet rays of that wavelength.In the present invention, the alignment film of the peripheral sealing area on the glass substrate surface is completely removed by irradiation with far ultraviolet rays. Alternatively, the concentration of the alignment agent can be lowered. This invention improves the sealing performance of the seal resin and improves the durability and reliability of the liquid crystal display device.

The lamp of the ultraviolet irradiation device used in the uninvented method is an ozone-generating type lamp that emits light with a wavelength of up to around 20 onm. No effect can be expected. Further, in the examples described later, a suitable irradiation time is 3 minutes or more, but this can be shortened by reducing the distance between the light source and the object to be irradiated. In addition, when irradiating ultraviolet rays, a mask corresponding to the liquid crystal display pattern on the glass substrate is used, and an alignment coating is applied. You need to mask the parts you want to keep.

Hereinafter, the present invention will be explained in detail using specific examples.

(Example 1) As an organic silane case springing agent, 0DYES (octadecyltriethoxylane, manufactured by Chisso ■) was used. After immersing this 0DTES in a 0.3% propyl alcohol solution for 2 minutes, the glass substrate on which the alignment film was completely formed was heated and dried for 0 minutes, 1 minute, 3 minutes, 5 minutes, and 10 minutes. All samples were prepared after being fully irradiated with ultraviolet rays. The ultraviolet lamp used was a 1.6 iKW high-pressure mercury lamp (ozone generation type), and the distance between the light source and the sample during irradiation was 13.6 m.

In order to investigate the degree of "jiki" on the surface of these samples, the contact angle when a water droplet was dropped was measured.

The results are shown in FIG.

As is clear from Figure 2, the contact angle of the masked part (white circle in the figure) is constant at 84 dog to 87 dig, whereas the contact angle of the part exposed to ultraviolet irradiation is It can be seen that the contact angle (black circle in the figure) rapidly decreases after 3 to 6 minutes of irradiation, and the surface roughness improves.

From this result, 0DTIC8 is decomposed by far ultraviolet rays,
It was shown that it had been removed.

Furthermore, similar samples were pasted together using sealing resin to create a test piece, and this test piece was used to create the test pieces shown in Figures 3a and b.
A tensile shear test was conducted to evaluate the performance improvement of the sealing resin. Ten test pieces as shown in Figure 3 were prepared for each UV irradiation time, and each adhesive area was 0.
．． 13C-. In addition, in FIG. 3, 2 is an adhesive part. The results are shown in Table 1. In addition, in the name of the table,
Y and E are the types of sealing resins, Y is an epoxy resin using an acid anhydride curing agent, and E is an epoxy resin using an amine curing agent. Further, BL indicates the laminated glass which has not been subjected to an orientation treatment, and each number indicates the time (minutes) of ultraviolet irradiation applied to the glass which has undergone an orientation treatment. In addition, the number of test pieces indicates the number of test pieces in which there was no substantial adhesion, and the number of glass breaks indicates the number of test pieces in which the tensile shear strength of the bonded part was greater than or equal to the breaking strength of the glass. .

Table 1 The results of Table 1 show that the adhesive strength of the sealing resin can be greatly increased by applying ultraviolet irradiation for about 3 minutes.

(Example 2) A glass substrate 7 with oriented gold foil similar to that in Example 1 was prepared, and the display pattern of this glass substrate was masked entirely except for the seal portion, and ultraviolet rays were irradiated for a total of 6 minutes in the same manner as in Example 1. Ta. This glass substrate is fully bonded with sealing resin,
All containers for liquid crystal display devices were made and a peel strength test was conducted. As a result, all of the containers showed strength greater than the breaking strength of glass.

(Example 3) TTS (isopropyl triisostearoyl titanate) was used as a titanate coupling agent.

A 1.6% propyl alcohol solution of this TTS was prepared using Ajinomoto Co., Ltd.), and all samples were prepared in the same manner as in Example 1. For this sample, all contact angles with water droplets were measured and the results are shown in FIG.

As is clear from FIG. 4, the irradiation for about 6 minutes resulted in very good removal, indicating that the TTS was decomposed and removed by the deep ultraviolet rays.

(Comparative Example 1) A similar evaluation was conducted using an ozone-less type lamp instead of the ozone generating type lamp used in Examples 1 and 2, but according to this company, the UV irradiation time was 20 minutes. However, no change was observed in the contact angle, and no improvement in the adhesive strength of the sealing resin was observed. As a result of the peel strength test, 0
．． 6-1. Everything peeled off with OK.

Here, in the above explanation, silane-based and titanate-based coupling agents were explained, but as shown in Table 2, the wavelength is 260 nm or less (the energy is 114 Kcal/m
Almost all organic bonds can be broken by ultraviolet rays (o1 or higher), and are not limited to those mentioned above.

Table 2 (according to Chemical Handbook Basic Edition 11) As described above, by using the uninvented manufacturing method, it is possible to completely improve the sealing performance around the glass substrate surface, thereby increasing the durability of the liquid crystal display device. Reliability can be improved.

[Brief explanation of the drawing]

Figure 1 is a model diagram showing the state of the surface of a glass substrate coated with oriented gold foil using a silane-based coupling agent. Figure 2 is a 10-page diagram showing the results of an embodiment of the uninvented manufacturing method, showing the UV irradiation time and water droplets. Figures 3a and 3b are side views and top views showing the state of a tensile shear strength test conducted to fully confirm the effects of the non-inventive manufacturing method, and Figure 4 is a diagram showing the relationship with the contact angle. FIG. 3 is a diagram showing the relationship between the ultraviolet irradiation time and the contact angle of water droplets as a result of another example of the manufacturing method.

Claims (1)

[Claims] A wavelength of 250 nm is applied to the liquid crystal aligning agent in the sealing area where the sealing resin around the opposing glass substrate surfaces is attached.
A method for manufacturing a liquid crystal display device characterized by irradiation with far ultraviolet rays as described below.