JP2003262858A - Liquid crystal display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a long-life and high quality liquid crystal display device without exfoliation. <P>SOLUTION: A transparent electrode 4 and an alignment layer 6 are successively formed on a glass substrate 3, the electrode 4 and the layer 6 are also successively formed on a glass substrate 8 and the substrates are stuck to each other with a sealant 5 via a liquid crystal layer. An optical retardation film and a polarizing film 2 are successively laminated on an outside surface of the glass substrate 3 and the retardation film and the film 2 are also successively laminated on an outside surface of the glass substrate 8. In addition, a synthetic resin material 1 is applied to peripheral edges of the polarizing films 2. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal display device in which a polarizing film is provided on a liquid crystal display panel.

[0002]

2. Description of the Related Art In recent years, liquid crystal display devices have been widely used as display devices for monitors and industrial equipment, or as display devices that can be used outdoors such as portable information terminals.
According to this liquid crystal display device, various driving methods such as an active matrix method and a simple matrix method have been developed.

In the field of application of such a liquid crystal display device, there are small devices such as calculators and watches in the early days, and then laptop personal computers, word processors, liquid crystal color projectors, in-vehicle navigation systems,
It has spread to a wide range of LCD TVs and indoor and outdoor measuring instruments.

According to such a liquid crystal display device, a laminated body of polarizing films having a light transmitting and shielding function is usually provided even if various driving methods are adopted.

Today, this polarizing film is a basic constituent element of a liquid crystal display device together with a liquid crystal material having a light switching function.

This polarizing film laminate is generally prepared by uniaxially stretching a polyvinyl alcohol-based polymer film (hereinafter, polyvinyl alcohol-based polymer is abbreviated as PVA) and dyeing it to form a polarizing film and three outer surfaces thereof. This is a structure in which a supporting plate such as cellulose acetate (TAC) is attached.

Further, as a non-optical rotatory film having a retardation value of 30 μm or less in a polarizing film, a polycarbonate resin, polysulfone, polyether sulfone,
A film of polysulfone resin such as polyallyl sulfone, polyolefin resin, cellulose triacetate resin or polyarylate resin having a thickness of 10 to 5
In some cases, a phase difference film having a thickness of 00 μm is attached to form an integrated product.

Furthermore, JP-A-6-313809,
JP-A-8-190017, JP-A-6-281817 and JP-A-8-190015 propose techniques for improving the performance and durability of a polarizing film laminate.

[0009]

In recent years, liquid crystal display devices have been used under a wide range of conditions of low temperature to high temperature and low humidity to high humidity. Therefore, a liquid crystal display device having more excellent heat and humidity resistance than conventional products can be obtained. It has been demanded.

However, according to the above-mentioned prior art, although the hygroscopicity / moisture permeability of the polarizing plate is reduced, satisfactory performance has not been achieved yet.
In particular, when the liquid crystal display device is driven under high temperature and high humidity conditions, peeling may occur from the adhesive layer due to the lamination of the polarizing film and the bonded portion between the laminated body of the polarizing film and the glass of the liquid crystal display device.

In particular, when the adhesive layer is left in a high temperature and high humidity condition for a long time, moisture permeates into the layer and deteriorates, so that the adhesive strength is lowered.

Therefore, an object of the present invention is to solve the above problems and provide a liquid crystal display device having excellent durability and resistance to moist heat.

[0013]

A liquid crystal display device according to the present invention comprises a member on which a transparent electrode and an alignment film are sequentially formed on a substrate, and a transparent electrode and an alignment film are sequentially formed on the substrate. A device in which a polarizing film is disposed on the outer surface of the substrate, with respect to a liquid crystal display panel in which the other member is disposed so as to face each other with a liquid crystal interposed between the transparent electrodes so that pixels are arranged in a matrix. In the configuration, a synthetic resin material is applied to the peripheral edge of the polarizing film.

Further, the liquid crystal display device of the present invention is characterized in that the synthetic resin material is extended to an end face of the liquid crystal display panel.

Furthermore, the liquid crystal display device of the present invention is characterized in that the coated synthetic resin material is subjected to deaeration treatment.

Further, the liquid crystal display device of the present invention is characterized in that the synthetic resin material is selected from acrylic resin, epoxy resin or urethane resin.

[0017]

BEST MODE FOR CARRYING OUT THE INVENTION The liquid crystal display panel according to the liquid crystal display device of the present invention has various configurations according to its driving system, but in this example, the STN simple matrix type liquid crystal display device will be described.

FIG. 1 shows a schematic sectional view of a liquid crystal display device of the present invention, and FIG. 2 is a plan view of the liquid crystal display device.

3 is a glass substrate on the segment side, and 8
Is a glass substrate on the common side.

On the glass substrate 3, transparent electrodes 4 made of ITO arranged in parallel in stripes and an alignment film 6 made of polyimide resin rubbed in a certain direction are sequentially formed, thereby forming the one member. .

Regarding the other member, a transparent electrode 4 made of ITO arranged in parallel in a stripe pattern on a glass substrate 8 and an alignment film 6 made of a polyimide resin rubbed in a certain direction are sequentially formed. .

The one member and the other member formed as described above are formed by bonding with the sealant 5 through the liquid crystal layer made of chiral nematic liquid crystal twisted at an angle of 200 ° to 270 °, for example. . In this bonding, both transparent electrodes 4 and 4 are arranged so as to be orthogonal to each other, each orthogonal portion is formed as a pixel, and these are arranged in a matrix. Reference numeral 7 is a spacer contained in the liquid crystal layer.

According to the transmissive mode liquid crystal display device, a backlight (not shown) is further provided.

FIG. 1 shows an example of a transmissive liquid crystal display device. In this mode, a retardation film (not shown) made of polycarbonate or the like and a polarizing film 2 are provided on the outer surface of a glass substrate 3. The retardation film (not shown) made of polycarbonate or the like and the polarizing film 2 are sequentially stacked on the outer surface of the glass substrate 8.

According to the liquid crystal display device having the above structure, the irradiation light of the backlight passes through the liquid crystal display panel through the polarizing film 2 and the retardation film, and subsequently passes through the retardation film and the polarizing film 2, thereby Is displayed.

According to the present invention, the polarizing film 2
The synthetic resin material 1 is applied to the peripheral edges of the.

The structure of the polarizing film 2 will be described with reference to FIG. The figure is a schematic sectional view, in which a polyvinyl alcohol polymer film (PVA film) is uniaxially stretched,
Support plates 9 made of cellulose triacetate (TAC) or the like are attached to both outer surfaces of the polarizing film 10 formed by dyeing.

The retardation film is bonded to such a bonded body. That is, it is made of a polycarbonate resin which is a non-optical rotatory film having a retardation value of 30 μm or less, a polysulfone resin such as polysulfone, polyether sulfone, and polyallyl sulfone, a polyolefin resin, a cellulose triacetate resin or a polyarylate resin. Thickness 10
The retardation film 12 having a thickness of 500 μm is attached by the adhesive 11.

Polarizing film 2 with such a retardation film
The integrated product is attached to the glass substrates 3 and 8 with the adhesive 11.

The adhesive 11 is, for example, TAC or PV.
A, TAC, acrylic adhesive, polycarbonate,
An acrylic adhesive may be used.

Next, the synthetic resin material 1 will be described. Regarding the synthetic resin material 1 applied to the peripheral edge of the polarizing film 2,
It is preferable to select an acrylic resin, an epoxy resin, or a urethane resin having low hygroscopicity and moisture permeability. Other,
Although a silicone resin may be used, the former resin may be selected because it has a high water permeability. Solventless urethane-based resins are especially suitable.

Then, after the laminated body of the polarizing film 2 composed of the adhesive 11 is pasted, the laminating portion of the laminated portion of the polarizing film 2 with a dispenser, and the laminated body of the polarizing film 2 and the liquid crystal display panel. The synthetic resin material 1 is applied to the bonding portion between the glass substrate 3 and the glass substrate 3 and is cured by heating. As a result, a structure in which such a bonded portion is closed is obtained, and as a result, a liquid crystal display device having excellent durability and resistance to moist heat can be obtained.

The resin applied from the dispenser may be adjusted so that the synthetic resin material 1 does not enter the effective display area of the liquid crystal display device.

Thus, according to the liquid crystal display device of the present invention,
By applying the synthetic resin material 1 to the peripheral edge of the polarizing film 2, even if the adhesive layer is placed in a high temperature and high humidity condition for a long time, moisture or the like does not penetrate into the layer, As a result, a liquid crystal display device having a long life and high quality that does not peel off was obtained.

According to the present invention, the synthetic resin material 1 may further extend to the end face of the liquid crystal display panel, whereby
Further, the following operational effects are exhibited.

FIG. 4 is a schematic cross-sectional view of a liquid crystal display device having such a structure, and the same parts as those of the liquid crystal display device shown in FIG.

If the synthetic resin material 1 is extended to the end surface of the liquid crystal display panel so that the polarizing films 2 are attached to both sides of the panel, the synthetic resin material 1 is applied to both sides in common. You can

Conventionally, since the transparent electrode 4 extends outside the sealant 5, there has been a problem that the electrode corrodes, thereby deteriorating the display performance. By extending the synthetic resin material 1 to the end surface of the liquid crystal display panel, the extended electrode is covered,
It was possible to prevent corrosion of the electrodes.

Moreover, since the sealing agent 5 is also covered, moisture and bubbles do not enter the liquid crystal layer through the sealing agent 5.

Furthermore, the glass substrate 3 and the glass substrate 8
Even if a foreign matter enters the space due to the formation of the gap between and, the occurrence of the situation could be prevented by extending the synthetic resin material 1 to the end surface of the liquid crystal display panel. .

Further, according to the present invention, it is desirable to perform the deaeration treatment on the coated synthetic resin material 1.

By sequentially passing through the following steps (a) to (e), it is possible to achieve removal of moisture and prevention of intrusion of moisture on the bonding surface of the polarizing film 2.

Step (a): The liquid crystal display panel is washed and dried to remove impurities, water and the like.

Step (b): The polarizing film 2 is attached to the liquid crystal display panel as described above.

Step (c): A synthetic resin material is used for the bonding part of the laminated part of the polarizing film 2 and the bonding part between the laminated body of the polarizing film 2 and the glass substrate 3 of the liquid crystal display panel with a dispenser. Apply 1.

FIG. 5 shows an outline of the dispenser, 9 is a dispenser head, and 10 is a nozzle. Resin is dropped from this nozzle 10 and applied. Then, by appropriately determining the application conditions such as the application pressure, the diameter of the nozzle 10 and the nozzle moving speed, it is possible to apply an appropriate amount to a required portion.

Step (d): The liquid crystal display device obtained in the previous step is inserted into a vacuum chamber, and the applied synthetic resin material 1 is subjected to heat treatment, and water and the like in the resin are removed. Foam.

Step (e): Continuously, for the above resin,
It is cured by heating at a higher temperature.

Through the above steps, the water and bubbles in the resin are removed, so that the water and the like in the resin does not penetrate into the polarizing film 2.

Further, after the polarizing film 2 is once attached, the water and the like adhering to the periphery thereof is removed. Therefore, the attached matter does not penetrate into the polarizing film 2.

By removing the moisture and air bubbles in this way, the resin further enters the removed portion, and as a result, a further sealed and sealed state is obtained. Can be prevented from penetrating.

In the present invention, as described above, the synthetic resin material 1 is applied and then defoamed, but there is no problem even if a rupture mark of bubbles is left by being removed from the display portion.

By setting the defoaming conditions, even if the bubbles burst, their influence can be reduced or eliminated.

Next, the point of using a solventless urethane resin as the synthetic resin material 1 will be described. The two-liquid mixed type solventless urethane resin raw materials are separately put into the material tank and then supplied to the head section for coating. In this head section, these materials are supplied to a chamber with a mixer for each mixing ratio. It is supplied, then sent to the coating valve, and coating is carried out on a predetermined portion by the dispenser as described above.

According to such a solvent-free urethane resin, no solvent is contained, which further reduces the problem that a slight amount of water is mixed in the solvent as in the conventional case, and the corrosion or the wiring portion is not corroded. It is the most effective against the problem of peeling.

Further, since the step of removing the water in the solvent as in the past is not necessary, the manufacturing efficiency is increased and the low cost liquid crystal display cell can be provided.

Regarding the viscosity of such a solventless urethane resin, the present inventor applied the coating by changing the viscosity of the solventless urethane resin within a range of 2000 mPa · s to 50000 mPa · s. When the relationship between the thickness, external strength, and coatability was measured, the viscosity of the solventless urethane resin was set in the range of 5000 mPa · s to 40,000 mPa · s. It turned out to be excellent.

Further, the viscosity of the solventless urethane resin is 5
By setting it in the range of 000 mPa · s to 40,000 mPa · s, even if there was a difference in height due to each member, it was possible to sufficiently protect against these.

Furthermore, according to the present invention, the solventless urethane resin has the effect of obtaining sufficient strength against external stress. The preferable resin thickness is as follows.
It should be 0.5 mm or more, preferably 1.0 mm or more.

The viscosity of the solvent-free urethane resin is adjusted by increasing the carbon number of the polyisocyanate used as a material or by adding various additives such as a filler, a defoaming agent and a crosslinking agent. This filler is made of silica, silicone rubber, Teflon (registered trademark), or the like.

Further, the hardness of the solventless urethane resin 2 was changed in various ways within the range of 20 to 200 degrees, and the relationship between the external strength and the thermal shock resistance was measured. It was found that by setting the hardness of the solventless urethane-based resin in the range of 60 to 100 degrees, both the external strength and the thermal shock resistance were excellent. The hardness of the solventless urethane resin is adjusted by increasing the carbon number of the polyisocyanate or by adding various additives such as a filler, a defoaming agent and a crosslinking agent, as in the case of adjusting the viscosity.

The present invention is not limited to the above embodiment, and various modifications and improvements can be made without departing from the scope of the present invention.

For example, regarding the liquid crystal display device,
The STN simple matrix type liquid crystal display device of the transmission mode has been described, but instead of this, in the case of the reflection mode liquid crystal display device, a light reflecting film or the like is provided to have a light reflecting function, and It is sufficient to provide one polarizing film 2 on only one member without using a backlight.

In order to use the liquid crystal display device of this embodiment for color display, a color filter may be formed.
Furthermore, instead of the simple matrix drive, an active matrix drive system such as a TFT may be used.

Further, according to this example, the polarizing film 2 having the retardation film bonded thereto is used as an integrated product, but instead of this, a polarizing film having no retardation film bonded thereto is used. It may be provided with a retardation film or a light scattering plate.

[0066]

As described above, according to the liquid crystal display device of the present invention, since the peripheral edge portion of the polarizing film is coated with the synthetic resin material as described above, the adhesive layer is particularly hot and humid. Even if the liquid crystal display was left for a long period of time, moisture and the like did not permeate into the layer and it was not deteriorated, and as a result, a liquid crystal display device having a long life and high quality was obtained.

[Brief description of drawings]

FIG. 1 is a schematic cross-sectional view of a liquid crystal display device of the present invention.

FIG. 2 is a schematic plan view of a liquid crystal display device of the present invention.

FIG. 3 is a cross-sectional view of a polarizing film.

FIG. 4 is a schematic cross-sectional view of another liquid crystal display device of the present invention.

FIG. 5 is a front view showing the outline of a dispenser.

[Explanation of symbols]

1 resin 2 Laminated film of polarizing film 3 glass substrates 4 Conductive film (transparent conductive film) 5 Seal layer 6 Alignment film 7 Spacer 8 glass substrate (opposite glass substrate) 9 TAC 10 PVA 11 Adhesive 12 Polycarbonate resin

Continued front page    F-term (reference) 2H049 BA02 BC10 BC14 BC22                 2H089 HA17 HA40 JA10 JA11 KA15                       QA07 QA08 TA06 TA15                 2H091 FB02 FB12 FD09 FD11 FD14                       GA01 GA17 LA02 LA04 LA06                       LA07 LA11 LA15

Claims (4)

[Claims] 1. A transparent electrode and an alignment film are sequentially formed on a substrate, and a transparent member and an alignment film are sequentially formed on a substrate. In a liquid crystal display device in which a polarizing film is disposed on the outer surface of the substrate, in contrast to a liquid crystal display panel in which pixels are arranged so as to face each other with a liquid crystal interposed therebetween, in a peripheral end portion of the polarizing film. A liquid crystal display device characterized by being coated with a synthetic resin material. 2. The liquid crystal display device according to claim 1, wherein the synthetic resin material is extended to an end surface of the liquid crystal display panel. 3. The liquid crystal display device according to claim 1, wherein the coated synthetic resin material is deaerated. 4. The liquid crystal display device according to claim 1, wherein the synthetic resin material is selected from acrylic resin, epoxy resin, and urethane resin.