JPS63137213A - Liquid crystal display element - Google Patents

Abstract

PURPOSE:To improve the shock resistance of a panel by providing a partition wall which is made of positive photosensitive resin in a thin-width, double shape between liquid crystal and outside and a set adhesive layer between the partition wall and outside. CONSTITUTION:Transparent picture element electrodes 4 are provided on a transparent substrate 3, an insulating film 19 is formed on the electrodes 4 when necessary, and an orienting film 5 is further provided to form a 1st panel A'. Transparent picture element electrodes 8 are provided on a transparent substrate 9 and an insulating film 13, etc., are provided on the electrodes 8 when necessary to form a 2nd panel B'. The panels A' and B' are set opposite each other. Then their gap is held by a spacer 4 and the panels are joined by a sealing cylinder 12 made of the positive photosensitive resin in thin, double structure. A ultraviolet-setting or thermosetting adhesive is put in both panels A' and B' outside a sealing layer 12 in a cell plane direction and set to form the set resin layer 17. Consequently, the shock resistance of the panel is improved.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a liquid crystal display device, and more particularly to a liquid crystal display element suitable for encapsulating a ferroelectric liquid crystal.

(Prior art) Figure 3 shows twisted nematic ink (hereinafter abbreviated as TN).
An example of a transmission type liquid crystal display element using type liquid crystal is shown below. The light source (1) is a three-wavelength fluorescent lamp, natural light, or the like. Light source (1)
The light emitted from the polarizer (2), the transparent substrate (3), and the pixel electrode (
4), passes through an alignment film (5), a liquid crystal (6), an alignment film (7), an opposing pixel electrode (8), a transparent substrate (9), and an analyzer α0. The thickness of the liquid crystal (6) is maintained at constant intervals with spacers 〇〇. Furthermore, the liquid crystal (6) is protected from the outside air by the sealing material (2). When a voltage is applied between the pixel electrode (4) and the pixel electrode (8), this element operates as a display device. liquid crystal(
The thickness of 6) is 5 μm to 10 μm in conventional TN type liquid crystal display elements and guest-host type liquid crystal display elements,
The thickness of the liquid crystal (6), that is, the electrode spacing was regulated by spacer 〇〇. The sealing material (2) is mainly responsible for joining the first panel (A) and the second panel (B). The sealing material @ was formed by printing an adhesive on the first panel (A) or the second panel (B) in advance using a silk screen or the like, and then bringing the two panels into close contact with each other and heating and curing the adhesive.

(Problems to be solved by the invention) Ferroelectric liquid crystals were developed by Meyer et al. (J. de Phys., 36
．． 69+1975) and its existence was demonstrated for the first time.

Clark and Lagerval (Appl, Phys, 1et
T, 36°899, 1980), an element consisting of ferroelectric liquid crystals sealed in narrowly spaced cells and oriented and two polarizing plates has high-speed response characteristics, memory It has superior properties compared to conventional liquid crystal elements, such as high effectiveness and high contrast ratio. However, the distance required at this time varies depending on the liquid crystal, but is often 3 μm or less.

However, with conventional panel forming methods, it was not only difficult to form spacers in this way, but also the sealing material
It is difficult to print uniformly to a size smaller than μm, and furthermore, it is extremely difficult to control the spread of the sealing material during lamination and limit it to a specific position and range.

These drawbacks can be almost solved by patterning the sealing layer using a lithography method. However, the sealing layer formed in this way generally has poor adhesion, and when it is formed using a positive photoresist, gas is generated by heating and the adhesion deteriorates further, causing a phenomenon that the durability of the panel deteriorates. This was insufficient to obtain good strength properties such as impact resistance.

(Means for solving the problem) The above problem was solved using the following means. That is, the liquid crystal is sandwiched between a first panel having at least a transparent pixel electrode on a transparent substrate and an alignment film on the pixel electrode, and a second panel having at least a transparent pixel electrode on a transparent substrate. In a liquid crystal display element, a narrow partition wall made of a positive photosensitive resin and having at least a double shape is interposed between the first panel and the second panel, and the partition wall is interposed between the liquid crystal and the outside. By providing a cured adhesive layer between the two, it was possible to obtain a liquid crystal display element with excellent strength characteristics.

(Structure of the Invention) FIGS. 1(A) and 1(B) show the structure of a liquid crystal display element according to the present invention. A transparent pixel electrode (4) is provided on a transparent substrate (3), an insulating film Q91 is formed as necessary on the pixel electrode (4), and an alignment film (5) is further provided on the first panel (A'). ), a transparent pixel electrode (8) is provided on a transparent substrate (9), an insulating film αj is formed as necessary on the pixel electrode (8), and an alignment film (7) (not shown) is formed as necessary. )
facing the second panel (Bo) provided with , the distance is maintained by a spacer 00, and joined by a sealing layer (2) made of a positive photosensitive resin having a narrow shape and at least a double structure provided by a lithography method. do. Furthermore, after that, an adhesive such as an ultraviolet ray (hereinafter abbreviated as UV) curing type or a thermosetting type is placed between the first panel and the second panel on the outside of the sealing 1u in the cell plane direction and is cured to form an adhesive layer αη. do.

That is, if adhesive is applied to the edge of the cell and conditions such as temperature are controlled to further reduce the viscosity, it will be injected between the internal substrates due to interfacial tension and blocked by the sealing layer (2). By performing a curing treatment here, it becomes an adhesive layer αη.

The transparent substrate (3) and the transparent substrate (9) have a thickness of 0.
A glass substrate of 5 mm to 5 mm can be applied. The material is preferably optically polished alkali-free metal glass, but it may also be blue plate glass coated with silicon oxide. Pixel electrode (4
) and the pixel electrode (8) are formed by forming films of tin oxide, indium oxide, or ITo, which is a mixture thereof, by sputter deposition or the like, and patterning them into arbitrary shapes according to a conventional method. The alignment films (5) and (7) are coated with polyvinyl alcohol, polyimide, or the like by an offset printing method, a spin coating method, or the like, dried, buttered as necessary, and then rubbed. Further, as the alignment films (5) and (7), an obliquely vapor-deposited layer of an inorganic material such as silicon oxide may be used.

The insulating films α■ and α1 are formed by sputtering or the like using silicon oxide or aluminum oxide to a thickness of 0.1 μm to 0.5 μm, if necessary. Insulating film Q31. (IΦ is
Improve pressure resistance. Furthermore, as shown in FIG. 2, a color filter (2) may be formed on the first panel or the second panel if necessary.

A positive photoresist is used for the soil layer α.

In addition, when using a ferroelectric liquid crystal, the sealing layer (2) is preferably formed to have a thickness of about 0.1 μm to 3 μm. The spacer 〇〇 that maintains the distance between the liquid crystal cells is 0.1μ.
Uniform particles made of glass, new ceramics, resin, etc. and having a diameter of about 3 μm to 3 μm can be used. Alternatively, it may be formed in the same manner when forming the sealing layer.

(Effects of the Invention) In the conventional method of forming a sealing layer, it was extremely difficult to pattern a desired shape with a thickness of 3 μm or less, but according to the present invention, it is possible to use a photosensitive resin for the partition wall. As a result, a thickness of 3 μm or less can be produced with good reproducibility, and since a curable adhesive layer is provided on the outside in contact with the outside world, it is possible to produce a panel with good strength characteristics. In addition, since the sealing layer is narrow and has a double or more shape, even if a material that generates decomposed gas when irradiated with light or heated, such as a positive-type photoresist resin, is used, the decomposed gas will be sealed. Since the air is exhausted through the gaps between the partition walls of the layers, there is no possibility that the sealing layer will peel off from the substrate due to the generation of decomposition gas.

(Example) [Example 1] A transparent substrate (3) was obtained by optically polishing a 3-inch square glass substrate with a thickness of 1.6+am to achieve a flatness of within 2 μm. A 400-layer ITO film was formed on the transparent substrate (3) by a sputtering method, and a pixel electrode (4) in a line pattern with a line width of 200 μm, a pitch of 300 μm, and a length of 60 mm was formed using a conventional photoetching method. did. Next, the pixel electrode (4) was coated with polyimide resin PIX-1400 (manufactured by Hitachi Chemical) using a spinner at 3000 rpm for 2 minutes at 80°C for 15 minutes, 200°C for 30 minutes, and 300°C for 30 minutes. After cooling, orientation treatment was performed using a rubbing device to form an orientation film (5) to obtain a first panel (A).On the other hand, a 3-inch square with a thickness of 1.6
*N glass substrate was optically polished to a flatness of 2 μm or less, and an ITO film was formed on the surface of the transparent substrate (9) by the spackle method, and the surface flatness was 20 μm in the line as in the previous period.
After forming a pixel electrode (8) in a line pattern with a pinch of 300 μm and a length of 60 squares, a silicon oxide film was formed as an insulating film α by sputtering to obtain a second panel (B''). On the panel (B), apply a positive photoresist MP-1350 (manufactured by Sibley) for 20 minutes using a spinner.
Coating was carried out at 00 rpm for 30 seconds, and a spacer α having a square size of 50 μm was provided between the pixel electrodes according to a conventional photoetching method. Also, at the same time, 0.5m in the line
The triple sealing N@ patterning was also carried out using m. At this time, the film thickness after development was 0.6 μm. Next, the first panel (A゛) and the second panel (B') are sealed together, and 1 kg
/ci, the temperature was increased from room temperature to 160° C. at 6° C./min, held for 1 hour, and then cooled and the pressure was removed to prepare an element for liquid crystal encapsulation. Through the above steps, both panels were bonded together using the spacer ○a and the sealing layer (2).

Furthermore, after forming the panel, an adhesive was applied to the periphery of the panel except for the liquid crystal filling opening aO. Epoxy-based LI as adhesive
Appropriate amounts of X0NBOND-1001A and 1001B (manufactured by Chisso ■) were mixed and provided.

After applying this, the viscosity can be temporarily lowered by placing the panel in an oven and keeping it at about 70°C. At this time, the fluidized adhesive penetrates between the panels due to interfacial tension. This is stopped by the previously formed sealing layer side. Furthermore, by degassing before heating and returning to normal pressure after heating, it is possible to inject more reliably by injecting at atmospheric pressure.

After the adhesive has sufficiently penetrated between the panels, heat the panels at 120℃ for 3
The adhesive layer αη was cured by heating for 0 minutes.

Note that the ITO film patterning at this time was performed according to the following procedure.

■ Apply positive photoresist on the ITO film and heat to 90℃.
After drying for 30 minutes, mask exposure was performed and developed with a special developer.
Post-baked for 30 minutes at °C.

(2) A mixed solution of ferric chloride solution and hydrochloric acid was heated to 60''C, and the ITO film-coated substrate was immersed therein for etching.

(2) The resist was removed using a film removing agent and washed with ultrapure water.

C31OII (manufactured by Chisso ■) was used as the liquid crystal. In addition, the liquid crystal was encapsulated using the following procedure.

(2) At room temperature and pressure, place the liquid crystal near the liquid crystal filling port 0[9 of the device without blocking it, and place it in an oven that can reduce the pressure.

■ Keep at room temperature and reduced pressure.

■ 120℃ and reduced pressure.

■ 120℃ and normal pressure.

■ Make sure the liquid crystal is completely inserted and let it come to room temperature.

A good liquid crystal display element was produced by the above operations.

[Example 2] A transparent substrate (3) was obtained by optically polishing a 3-inch square glass substrate with a thickness of 1.6 m1i to achieve a flatness of within 2 μm. A 400-layer ITO film was formed on the transparent substrate (3) by sputtering, and the line width was 200 μm, the pitch was 300 μm, and the length was 60 m according to the conventional photo etching method.
A pixel electrode (4) with a green pattern was formed. Next, polyimide resin PIX-1400 (manufactured by Hitachi Chemical Co., Ltd.) was applied onto the pixel electrode (4) using a spinner at 3000 rpm for 2 hours.
Coat at 80℃ for 15 minutes at 200''C.
After heating for 30 minutes and 300'C for 30 minutes, after cooling, alignment treatment was performed using a rubbing device to form an alignment film (5) to obtain a first panel (A"). On the other hand, a 3 inch square thickness A 1.6mm glass substrate was optically polished to improve its flatness by 2.
An IT○ film was formed by sputtering on the surface of a transparent substrate (9) processed within μm, and the line width was 200 as in the previous period.
After forming a pixel electrode (8) in a ten thousand green pattern with a pitch of 300 μm and a length of 601 seconds, a silicon oxide film was formed as an insulating film α by a sputtering method, and the second panel (B
゛) was obtained. Furthermore, a positive photoresist MP-1350 (manufactured by Sibley) was coated on the panel (B) using a spinner at 200 rpm for 30 seconds, and a spacer of 50 μm square was formed using a conventional photoetching method. 〇〇 was provided between the pixel electrodes. At the same time, a double-shaped sealing layer 03 with a line width of 1.0+u was patterned. At this time, the film thickness after development was 0.6 μm.

Next, the first panel (A") and the second panel (B') are sealed together and pressurized at Ikg/co! to 6°C/mtn from room temperature.
The temperature was raised to 160° C., held for one hour, cooled, and the pressure was removed to prepare an element for liquid crystal encapsulation. Through the above steps, both panels were adhered by the spacer circle and the sealing layer side.

Furthermore, after forming the panel, an adhesive was applied to the periphery of the panel other than the liquid crystal filling opening αe.

As an adhesive, TOV-163 manufactured by Osaka Organic Chemical Industry ■
1 was used. This product is fluid at room temperature and hardens by UV irradiation in a degassed state.

Therefore, when applied, the adhesive penetrates between the substrates due to interfacial tension and is stopped by sealing N(2). After the adhesive was sufficiently filled between the substrates, it was cured by irradiating with U₂ in a deaerated state to form an adhesive Na1.

Note that ITO film patterning was performed in the same manner as in Example 1 above.

In addition, the liquid crystal was sealed in the same manner as in Example 1 above.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram showing one embodiment of the liquid crystal display element of the present invention. FIG. 1(a) is a sectional view thereof, and FIG. 1(b) is a plan view thereof. FIG. 2 is a sectional view showing an example of a panel used in the liquid crystal display element of the present invention. FIG. 3 is an explanatory diagram showing an example of a conventional liquid crystal display element. (1)...Light source (2)...Polarizer (3), (9)...Transparent substrate (4), (8)...Pixel electrode (5), (7)...Alignment film (6)...Liquid crystal aω...Analyzer αυ...Spacer■...Sealing material or sealing layer α■, O seepage...Insulating film α...Spacer 0ω... Ferroelectric liquid crystal αω... Liquid crystal sealing opening αη... Adhesive layer

Claims (1)

[Claims] 1) A first panel in which at least a transparent pixel electrode is provided on a transparent substrate and an alignment film on the pixel electrode, and a second panel in which at least a transparent pixel electrode is provided on a transparent substrate. In a liquid crystal display element comprising a liquid crystal sandwiched between the first panel and the second panel, a partition wall made of a positive photosensitive resin and having a narrow width and at least a double shape is interposed between the liquid crystal and the outside. . A liquid crystal display element further comprising a hardened adhesive layer between the partition wall and the outside. 2) The liquid crystal display element according to claim 1, wherein an ultraviolet curable adhesive is used as the cured adhesive layer. 3) The liquid crystal display element according to claim 1, wherein a thermosetting adhesive is used as the cured adhesive layer.