JPS6023827A - Electrooptical device - Google Patents

Abstract

PURPOSE:To improve thermal stability and stability against the lapse of time by coating the surface of a base plate provided with a transparent conductive film with a prescribed resin, and subjecting the film to orientation treatment to form an electrode plate usable for a liquid crystal display device. CONSTITUTION:A display device comprises transparent base plates 11, 12, segment electrodes 13, a resin film 15, an insulating film 14, a common electrode 16, nematic liquid crystals 18, and polarizing plates 10, 19 intersecting each other rectangularly. The resin film 15 is made of a film obtained by hardening an acetoacetylated polyvinyl resin or polyvinyl phosphate resin in the presence of a water-insolubilizing agent having at least 2 active groups, such as ammonium bichromate, magnesium chloride, or glyoxal, and the films 14, 15 are subjected to orienting treatment in the directions intersecting each other rectangularly to orient the liquid crystals to twist them at a 90 deg. angle. When voltage is applied between the electrodes 13, 16, the molecular axis of the liquid crystals is oriented in the electric field direction, and incident light is intercepted with rectangularly intersecting polarizing plates 10, 19, resulting in black display. The film 15 is stable against both of heat and the lapse of time.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an electro-optical device, and particularly to a liquid crystal display device using nematic liquid crystal having positive dielectric anisotropy.

Nematic liquid crystal (abbreviated as N-liquid crystal) has an electric field, a magnetic field,
It is known that changes in optical characteristics due to the application of ultrasonic waves or the like can be used for display and can be used for light modulation and the like. This is usually an N-liquid crystal sandwiched between two substrates, at least one of which is transparent, which are placed facing each other with an interval of about 50 μm or less, and molecules that are generated by applying electric fields, magnetic fields, ultrasonic waves, etc. Changes in the arrangement are used for light modulation. When applying an electric field, a thin layer 4 is placed on one side of a support plate such as a glass plate as the substrate.
Use an electrode plate with electrical coating.

The compounds forming the above-mentioned N-liquid crystals can be divided into different types depending on the relationship between the molecular KA structure and dielectric properties.

One is a type in which the molecular axis and the electric dipole are approximately perpendicular (referred to as Nn), and the other is a type in which the molecular axis and the electric dipole are approximately parallel (referred to as Np). Nn means N-liquid crystal with negative dielectric anisotropy, and Np means N-liquid crystal with positive dielectric anisotropy. A commonly used Np-liquid crystal electro-optical device has a structure in which an Np-liquid crystal is sandwiched between two opposing 711K plates. In this case Np
- In liquid crystal, the molecular axes are parallel to the electrode plates, and the direction of the molecular axes is parallel to the electrode plates (1"4). In order to align the molecular axes in this way, the electrode surface is polished in one direction with two sheets of cloth, etc., and the two sheets are stacked so that the polishing directions cross each other. It can be constructed by injecting liquid crystal between them.It is known that near the electrode surface, the molecular axes are aligned in the polishing direction, but within the liquid crystal layer, the molecular axes are continuously twisted.

However, this method has the disadvantage that the orientation is not uniform and that the orientation is lost within a short time. It is known that orientation destruction occurs under heating.

As a method to solve these problems, it is known to use a certain kind of surfactant in combination to rub the electrode plate in one direction, but surfactant causes deterioration of the liquid crystal and makes it difficult to apply voltage. If this continues, the surfactant may be decomposed or altered by the electric field, and its orientation may be destroyed. Another known method is to coat the surface of an electrode plate with a certain type of polymer such as polyimide or polyamideimide, and to orient the coated polymer layer. However, the polyimide film formed by dehydration ring closure of a polyamic acid solution using a polar solvent such as dimethylacetamide has excellent heat resistance and orientation, but the processing temperature is 250°C.
℃~300℃ or more, and the solvent is dimethylformamide, dimethylacetamide, dimethyl sulfoxide,
At present, it is a highly toxic polar solvent such as N-methylpyrrolidone, so it must be handled with care. On the other hand, polyvinyl alcohol is a water-soluble resin that uses water as a solvent, and is not toxic like the solvents mentioned above and is easy to handle. However, when a film formed of polyvinyl alcohol is used for orientation change, , it has the disadvantage of poor durability.

It is an object of the present invention to provide a liquid crystal display device that has improved the above-mentioned points, and particularly to provide a liquid crystal display device that has improved alignment stability against heat and stability over time.

Such an object of the present invention is to electro-optically conduct an electrode plate in which the surface of the group provided with the conductive film is covered with a film of hardened acetoacetylated or phosphoric acid esterified polyvinyl alcohol resin, and the surface is oriented. This is achieved by using a device, especially a liquid crystal display device, as an electrode plate consisting of a'.

The acetoacetylated polyvinyl alcohol (hereinafter simply referred to as rPVAj) used in the present invention can be used, for example, while keeping the PVA resin in a fluidized state or in an agitated state, under reduced pressure, normal pressure, or even under increased pressure. It can be obtained by contacting with.

Contact temperature is 30-250°C, preferably 50-200°C
Although it is preferable to bring the resin into contact with the resin at a temperature and under diketene partial pressure conditions such that the gaseous diketene does not liquefy upon contact with the resin, it is acceptable that some of the gas may form droplets.

The contact time can be appropriately selected from the range of 1 minute to 6 hours depending on the contact temperature, that is, when the temperature is low, the time may be long, and when the temperature is high, the time may be short.

When diketene gas is supplied, diketene gas itself or a mixed gas of diketene gas and an inert gas may be used.The gas may be absorbed into powdered PVA resin and then heated. It is preferable to contact the gas after heating while heating.

Since water, methanol, and the like consume diketene, it is preferable to use the powdered PVA resin to be subjected to acetoacetylation after removing volatile components. The finer the fat, the better, with a particle size of 10 to 450 mesh, preferably 60 mesh or less.

Since PVA resin powder usually contains sodium acetate, it is often not necessary to add a catalyst, but the amount of sodium acetate is 0.01 to 2,050, preferably 0.1 to 2.05.
It is 1.0%.

Next, when acetoacetylating a PVA resin molded product, use a basic compound such as sodium acetate, potassium acetate, primary amine, tertiary amine, or tertiary amine in the same manner as in the case of powdered PVA resin. It is preferable to use it after adsorbing it to the surface of the molded article, if necessary.

PVA-based resins include PVA obtained by saponifying a lower alcohol solution of polyacetic acid beer with a saponification catalyst such as an alkali, and derivatives thereof, as well as Qi polymers that are copolymerizable with vinyl acetate and vinyl acetate. Containers of copolymers can be used.

The monomers include (anhydrous) maleic acid, fumaric acid, crotonic acid, itaconic acid, unsaturated carboxylic acids such as (meth)acrylic acid, and their esters, α-olefins such as ethylene and propylene, and (meth)allylsulfone. acids, olefin sulfonic acids such as ethylene sulfonic acid, sulfonic acid malate, sodium (meth)allylsulfonate, sodium ethylene sulfonate, sodium sulfonate (meth)acrylate, sodium sulfonate (monoalkyl maleate)
, olefin sulfonic acid alkali salts such as disulfonic acid soda alkyl maleate, amide group-containing monomers such as N-methylol acrylamide and acrylamide alkyl sulfonic acid alkali salts, as well as N-vinylpyrrolidone and N-vinylpyrrolidone derivatives. It will be done.

In addition, S/2-esterified PVA can be obtained by reacting PVA with phosphorus. The phosphoric acids used in this case include orthophosphoric acid, pyrophosphoric acid,
Oxygen atoms of phosphoric acids such as triphosphoric acid, tetraphosphoric acid, polyphosphoric acid, metaphosphoric acid, phosphorous acid, hypophosphoric acid, and hypophosphorous acid can be mentioned. PVA includes PVA having various degrees of polymerization and saponification, as well as monomers copolymerizable with vinyl esters such as vinyl acetate (e.g., ethylene, propylene, isobutylene, α-octene, α-dodecene, α- α-olefins such as octadecene, unsaturated carboxylic acids such as acrylic acid, methacrylic acid, crotonic acid, maleic acid, or their alkyl esters or acid amides, acrylonitrile or methacrylonitrile, vinyl ethers, vinyl ketones, olefin sulfonates, etc.) Also used are saponified copolymers of PVA, or PVA derivatives obtained by post-modifying PVA or copolymerized PVA by acetalization, urethanization, cyanethyl etherification, etc. In short, the vinyl alcohol polymer referred to herein may be one having at least a portion of vinyl alcohol units in the polymer.

When the reaction is carried out in a reactor equipped with a stirrer, the reaction temperature is usually about 50°C to 170°C, especially 60°C to 170°C.
Approximately 120°C is appropriate. If the reaction temperature is too low, it will take a long time for the reaction to proceed; on the other hand, if the reaction temperature is too high, there is a danger that the product will be colored or become insoluble.

As for the charging composition, it is appropriate to use 4 parts by weight or more of phosphoric acids per 100 parts by weight of vinyl alcohol polymer.

The content of acetoacetyl groups or phosphate ester groups in the PVA resin in the present invention can be 0.05 mol% or more, up to the maximum within the range of water solubility, but usually 0.05 mol% or more.
It ranges from 1 to 40 mol%, preferably from 0.2 to 20 mol%.

This PVA resin is, for example, dissolved in water or alcohols (methanol, ethanol, inglobil alcohol, etc.), and in this solution active agents such as ammonium dichromate, magnesium chloride, dimethylolated melamine, and dialdehydes are added as water-resistant insolubilizers. After adding the compound with two or more groups, it can be cured under predetermined curing conditions. The dialdehydes mentioned above include glyoxal,
Although malondialdehyde, succindialdehyde, glucurdialdehyde, maleidialdehyde, phthalaldehyde, isofucraldehyde, themphthalaldehyde and the like can be used, glyoxal and glutardialdehyde are preferred, with glyoxal being particularly preferred.

The blending ratio of the water-resistant insolubilizer to the PVA resin is
0.0% water-resistant insolubilizer per 100 parts by weight of resin. The amount may be 1 part by weight to 100 parts by weight, preferably IM part to 50 parts by weight.

The above-mentioned PVA resins containing ammonium dichromate can be cured by appropriate light irradiation, especially ultraviolet irradiation, and the above-mentioned PVA resins containing dimethylolated melamines and dialdehydes can be cured by suitable temperature irradiation. for example(
It can be cured by heating at 180 to 200°C.

Methods for applying the PVA resin used in the present invention on the electrode plate include brush coating, dip coating, spinner coating, and spray coating using a solution prepared by adding, for example, ammonium dichromate and glyoxal as water-resistant insolubilizers to a PvA aqueous solution. PV is applied to an electrode plate using a bar coating method, dried, and then cured under predetermined curing conditions.
A coating of resin is formed.

This cured PVA resin coating is made of chromic acid (Cry
s) Since it can be removed with an aqueous solution, for example, the above-mentioned PVA coating formed on the terminal part of the electrode plate and the seal spacer forming part during the process of creating a display device can be removed using a normal photolithography process and a chromic acid aqueous solution. In particular, it can be removed by removing it. In particular, use of this chromic acid aqueous solution can prevent contamination of the seal spacer.

The PVA fat coating that has been treated with the water-resistant insolubilizing agent is subjected to a homogeneous orientation treatment, for example, a rubbing treatment, in one direction using a cloth or the like. This oriented PVA resin coating can improve stability and stabilize orientation over time.

The electrode plate used in the liquid crystal display device of the present invention has at least one transparent conductive f (e.g., indium oxide, tin oxide, indium oxide-tin oxide (tin oxide, 0.1 to 40
It is preferable to use a substrate (glass, plastic, etc.) provided with a material (such as % by weight). Furthermore, the opaque electrocardial membrane used in the present invention can be made of aluminum, gold, silver, copper, lead, or the like.

The liquid crystal sealed in the display device of the present invention is not particularly limited, and various types can be used as appropriate. In particular, nematic liquid crystals with positive dielectric anisotropy, such as rZLI-1216j, r
ZLI-1253J, rZLI-1285J, rZL
I-1414J, rZLI-1565J and rZLI-1
694J etc. can be used. These liquid crystals are
They can be used alone or in combination.

Hereinafter, V/ of a liquid crystal display device as an electro-optical device of the present invention will be described.
The present invention will be explained by referring to numeral 11. In FIG. 1, 11 and 12 indicate substrates such as glass plates and plastic plates. Segment electrodes 13 patterned into a predetermined shape are formed on the inner surface of the substrate 11, and a film 15 of cured acetoacetylated or succinic acid esterified PVA resin is further coated thereon. At this time, the segment electrodes 13 can be formed of a transparent conductive film such as indium oxide or tin oxide.

The aforementioned coating 15 has a portion 17 covering the segment electrode 13.
can be stained using an appropriate method to display half-colors and identify them. The coating 15 has an opposing common electrode 16
When alignment treatment is performed by rubbing in directions that intersect with one of the insulators J1ij14 provided above, the liquid crystal 18 disposed therebetween is twisted and aligned at an angle of 900 degrees.

As the liquid crystal 18 used in this case, a nematic liquid crystal (hereinafter referred to as Np liquid crystal) having positive dielectric anisotropy is used.

Polarizing plates 10 and 19 in a crossed nicol state are arranged outside the liquid crystal cell having such a structure.

In this liquid crystal display device, for example, when a voltage is applied between the segment electrode 13 and the common electrode 160 shown in FIG. The black display 22 can be seen as a black display 22 in a liquid crystal display device 21 as shown in FIG. .

In the liquid crystal display device Δ shown in FIGS. 1 and 2, by using polarizing plates colored blue, gray, red, etc. as the polarizing plates 10 and 19, the color tone effect in this device can be enhanced.

In addition, behind the polarizing plate IO, there is a reflecting plate (
(not shown) can be placed.

As a method for dyeing the portion 17 covering the segment electrode 13, for example, the coating 15 is formed on a substrate having a transparent conductive coating patterned into a predetermined shape, and then a coating of photoresist material is further applied on the coating 15 ((a coating of a photoresist material). After forming the coating 15.2, the part covering the electrode is dyed by immersing it in a prescribed 2% ammonia solution so that the part other than the electrode part becomes a mask, and then the mask is removed. There are many ways to remove it.

Hereinafter, the present invention will be explained according to examples.

Example 1 Ammonium dichromate and glyoxal (ammonium dichromate: glyoxal = 1:1) were added to a 5% aqueous solution of acetoacetylated PVA obtained by the following method at a ratio of 5% by weight based on the solid content of PVA. Added. This solution was coated on the electrode plate for 10 seconds using a spinner coater rotating at 300° rpm to form 1500 coats, and then heated and dried at 120° C. for 30 minutes.

Next, the terminal part of the electrode plate 1a and the seal spacer -
In order to remove the coating on the forming area, a mask was formed on the area excluding the terminal area and the seal spacer forming area using a normal photolithography process, and then the electrode plate was soaked in a 10% chromic acid (Cross) aqueous solution. The film formed on the non-mask area was removed by immersion for 10 minutes. Thereafter, the resist was peeled off and reheated at 180° for 15 minutes.

Next, a pair of electrode plates provided with a PvA film were aligned by rubbing in one direction with a cloth, and then cell-assembled so that the rubbing directions were perpendicular to each other. company r ZLI-1253j)
After encapsulating the cell, a display device was created by pasting polarizing films on both sides of the outside of the cell so that the polarization directions of the polarizing films were parallel to the directions of the adjacent substrates (this was used as sample N).
[11].

On the other hand, as a comparison sample, rNL-05J manufactured by Nippon Gosei Kagaku Kogyo Co., Ltd. was used as a PVA that does not have an acetoacetyl group in place of the PVA used when creating the display device of sample N[Ll described above. Otherwise, the display device was created in the same manner as described above.

These samples were tested for 100 hours, 200 hours, and 300 hours at a temperature of 85°C and a relative humidity of 85%, respectively)4.
A forced aging test was performed on each sample by storing it at 00, 500 and 1000 hours.
The increase in current in the liquid crystal display device was measured over time. As a result, the sample I&L1 of the present invention was 10
Even after 00 hours, the increase in current is less than 10%,
Moreover, although sufficient liquid crystal display ability was observed, the current increase in the comparative sample after 1000 hours was 10% or more.

In addition, sufficient display ability was observed in this comparative sample even after 500 hours had passed.

Production example of acetoacetylated PVA PVA powder containing 0.3% sodium acetate (saponification degree 8)
8 mol %, particle size of 80 meters or less) in a kneader of 196
After adding 16.8 parts of liquid diketene by spraying over 30 minutes at room temperature while stirring at a rotation speed of 5 Q rpm, the temperature was raised to 60 ° C. and reacted for 3 hours.
Acetoacetylated P with a degree of acetoacetylation of 3.3 mol%
A VA resin was obtained.

Example 2 Except for using dimethylolated melamine as the water-resistant insolubilizer used when preparing sample N [L l of Example 1,
A display device was created in the same manner as in Example 1 (sample amount 2
).

When sample amount 2 was subjected to a forced aging test in the same manner as in Example 1, the current increase was less than 10% even after 1000 hours, and sufficient liquid crystal display ability was observed.

Example 3 A display device was produced in the same manner as in Example 2, except that phosphorylated PVA was used in place of the acetoacetylated PVA used in Example 2 (sample Nα3).

When sample Nα3 was subjected to a forced aging test in the same manner as in Example 1, the current increase was less than 10% even after 1000 hours, and sufficient liquid crystal display ability was maintained.
It was noticed.

In addition, phosphoric acid esterified PVA is PVA (polymerization degree 500
, degree of saponification 88 mol %) 10RF near 0° C. while pouring 30 cc of 85% orthophosphoric acid to react PVA and orthophosphoric acid.

Examples 4 to 5 A display device was created in the same manner as in Example 3, except that glyoxal was used as the water-resistant insolubilizer used when creating sample amount 3 in Example 3 (sample Nα4). Similarly, a display device was prepared using malondialdehyde as a water-resistant insolubilizing agent (sample ++115).

When a forced aging test of Na4 and Nα5 was conducted in the same manner as in Example 1, the current increase was less than 10% even after 1000 hours, and a good display was obtained.0 Example 6 A display device was created in the same manner as in Example 1, except that malondialdehyde was used as the water-resistant insolubilizer used when creating sample NIL 1 in Example 1 (sample amount: 6).

When a forced aging test was conducted on sample NIL 6 in the same manner as in Example 1, the current increase was less than 10% even after 1000 hours, and good display was obtained.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a liquid crystal display device of the present invention, and FIG. 2 is a plan view thereof. 11.12...Substrate 13...Segment electrode 14...Insulating film 16...Common electrode 17...Segment electrode 13 is connected to the 619 insulating film part (
18...Liquid crystal 10.19...Polarizing plate 21...Liquid crystal display device 22...Display by driving 23...Half display. Patent applicant Canon Co., Ltd. 10 Procedural amendment (voluntary) January 2, 1980 Commissioner of the Japan Patent Office Kazuo Wakasugi 1 Indication of the case 1981 Inter-patent patent No. 60268 2 Name of the invention Electro-optical device 3 Amendment Relationship with the patent applicant case Address: 3-30-2 Shimomaruko, Ota-ku, Tokyo Name (+0
0) Canon Co., Ltd. Residence (7) 3-30-2 Shimomaruko, Ota-ku, Tokyo 146
・Canono Co., Ltd. (Telephone: 758-2111) 5, Subject of the amendment: MB document and drawings 6, Contents of the amendment (1) "Group" on page 5, line 19 of the document A is corrected to "substrate." (2) Insert "polyvinyl alcohol" after "alcohol (hereinafter referred to as") on page 6, line 6 of the above. "Water and methanol consume diketene, so remove volatile matter such as water and methanol," should be corrected to "Water and methanol consume diketene, so remove volatile matter such as water and methanol." (4) Same as above, page 7, no. 16 line ~ page 8, line 1 [Next PV
A-based resin...It is preferable to use it. ” to be deleted. (5) Correct “polarization direction” in line 3 of page 18 of the above to “polarization direction” 0 (6) Correct figure 1 of the drawing to the attached drawing 〇0

Claims (1)

[Claims] (1) A transparent conductive coating is provided on at least one of the two.
In an electro-optical device comprising a liquid crystal layer sandwiched between two substrates, at least one of the electrode plates has a hardened acetoacetylated or phosphated polyvinyl alcohol resin coating M on its surface; An electro-optical device h0(
21. The electro-optical device according to claim 1, wherein the liquid crystal is a nematic liquid crystal having positive dielectric anisotropy. (3) Claim 1, wherein the cured acetoacetylated or phosphated polyvinyl alcohol resin is cured under predetermined curing conditions in the presence of a water-insolubilizing agent having at least two active groups. The electro-optical device described. (4) the water-resistant insolubilizer is ammonium dichromate;
4. The electro-optical device according to claim 3, which is at least one compound selected from Group 16 of compounds consisting of magnesium chloride, dialdehydes, and dimethylolated melamine. (5) The electro-optical device according to claim 4, wherein the water-resistant insolubilizing agent is glyoxal. (6) The electro-optical device according to claim 1, wherein the alignment treatment is a rubbing treatment. (7) The electro-optical device according to claim 1, wherein the polyvinyl alcohol resin coating is colored at a portion of the conductive coating forming the segment electrode.