JPH0643322A - Tacky adhesive polarizing plate - Google Patents

Abstract

PURPOSE:To facilitate peeling of a protective film even after a high-temp. resting stage and to prevent the failure of a liquid crystal display element and driving circuit by specifying the adhesive force of a tacky adhesive of a rubber system for adhering the protective film to a polarizing plate. CONSTITUTION:The tacky adhesive polarizing plate 1 constituted by including the polarizing plate 2 and the protective film 3 thereof is provided with the tacky adhesive layer 4 of the rubber system for adhering the protective film 3 to the surface of the base 2a of the polarizing plate 2. The base 2b of the polarizing plate 2 is provided with the tacky adhesive layer 65 for adhering the tacky adhesive polarizing plate 1 to the liquid crystal display element. A release film 66 which covers the tacky adhesive layer 65 and is peeled at the time of adhering the tacky adhesive polarizing plate 1 to the liquid crystal display element is provided. The adhesive of the rubber system which is about 10 to 100g/25mm width in the initial adhesive power to the polarizing plate 2 at ordinary temp. and is within about 1.5 times the initial adhesive power in the change of the adhesive power when the tacky adhesive polarizing plate 1 is rested for about two hours at about 70 deg.C is used for the tacky adhesive layer 4 of the rubber system in such a case.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an adhesive polarizing plate which is used by being adhered to a liquid crystal display element of a liquid crystal display device.

[0002]

2. Description of the Related Art A conventional adhesive polarizing plate used by adhering to a liquid crystal display element (liquid crystal display panel) of a simple matrix type or active matrix type liquid crystal display device is, for example, A protective film is attached to the surface of the polarizing plate to prevent it from getting dirty or scratched. That is, the adhesive polarizing plate is, for example, 2
A polarizing plate composed of a sheet of support and a polarizer sandwiched between them, a protective film attached to the surface of the polarizing plate, provided on the back surface of the polarizing plate, and the adhesive polarizing plate is used for liquid crystal display. A pressure-sensitive adhesive layer for adhering to the element and a release film covering the pressure-sensitive adhesive layer are laminated.

As a technique using such a polarizing plate, for example, a technical report of the Television Society of Japan
EJ Technical Report Volume 12, Number 3
2, pages 29-34, ID'88-75, August 1988 (ITEJ T
echnical Report Vol.12 No.32, pp.29-34, ID'88-75 (A
ug, 1988)).

[0004]

A protective film made of EVA (ethylene vinyl acetate copolymer) used in a conventional pressure-sensitive adhesive polarizing plate has a special pressure-sensitive adhesive layer interposed on the surface of the polarizing plate. It was a self-adhesive type that was adhered to the surface of the polarizing plate due to the characteristics of the material itself of the protective film only by bringing it into intimate contact with the surface of the polarizing plate.

After the adhesive polarizing plate is attached to the liquid crystal display element, a high temperature standing step is performed on the liquid crystal display element to which the adhesive polarizing plate is attached in order to stabilize the orientation of the liquid crystal material of the liquid crystal display element. (70 ° C x 2 hours) is applied.

The protective film made of EVA described above is a TA which constitutes a support of a polarizing plate after this high temperature heat dissipation step.
The affinity between C (triacetyl (triacetic acid) cellulose) and EVA of the protective film increases, heat curing proceeds, and the adhesive force of the polarizing plate to the support (hereinafter referred to as the polarizing plate adhesive force) is increased before the step. Of about 10 to 15 times that at room temperature.

With this, when the adhesive polarizing plate is attached to the liquid crystal display device and the protective film is peeled from the surface of the adhesive polarizing plate after the above high temperature standing step, the peeling work becomes difficult, and if peeling is forcibly performed, Peeling was not performed well, and the liquid crystal display element was sometimes damaged. Further, when the protective film is peeled off, a large amount of static electricity is generated, and this static electricity may damage the drive circuit of the MOS-IC of the liquid crystal display element.

The object of the present invention is to provide a high-temperature storage step,
You can easily peel off the protective film,
An object of the present invention is to provide an adhesive polarizing plate capable of suppressing damage to a liquid crystal display element and a drive circuit.

[0009]

In order to solve the above-mentioned problems, the present invention provides an adhesive polarizing plate comprising a polarizing plate and a protective film thereof, wherein the adhesive film adheres the protective film to the polarizing plate. A layer is interposed between the two, and
Initial adhesive strength to the above polarizing plate at room temperature is about 10
~ 100g / 25mm width and about 7
Provided is a pressure-sensitive adhesive polarizing plate using a rubber-based pressure-sensitive adhesive as the pressure-sensitive adhesive layer, wherein the change in the above-mentioned adhesive force when left at 0 ° C. for about 2 hours is within about 1.5 times the initial adhesive force.

Further, the protective film is characterized by being made of transparent polyester (PET), polypropylene (PP) or polyethylene (PE).

The conventional protective film made of EVA has the property of being melted by heat and increasing the adhesive force, and the affinity between TAC constituting the support of the polarizing plate and EVA of the protective film is increased by leaving it at a high temperature. The degree of changes greatly depending on the content of vinyl acetate. The present invention provides a pressure-sensitive adhesive polarizing plate having a weakly viscous pressure-sensitive adhesive and a base material of a protective film, which does not increase the adhesive force to the polarizing plate due to heating at the interface between the support of the polarizing plate and the protective film. .

[0012]

In the pressure-sensitive adhesive polarizing plate of the present invention, since the above-mentioned rubber-based pressure-sensitive adhesive is used to attach the protective film to the polarizing plate, the interface between the support of the polarizing plate and the protective film is maintained even after the high temperature standing step. Does not increase the adhesive strength. Therefore, the work of peeling the protective film can be easily performed, and damage to the drive circuit due to the liquid crystal display element or generated static electricity can be suppressed.

[0013]

EXAMPLE FIG. 1 is a partial sectional view of an adhesive polarizing plate of an example of the present invention. 1 is an adhesive polarizing plate, 2 is a polarizing plate, 2a,
Reference numeral 2b is a support for the polarizing plate, 2c is a polarizer, 3 is a protective film, 4 is a protective film 2 for the support 2 of the polarizing plate 2.
The rubber-based pressure-sensitive adhesive layer 65 for adhering to the surface of a is provided on the support 2b of the polarizing plate 2, and the adhesive polarizing plate 1 is adhered to a liquid crystal display element (not shown here) (see FIGS. 4 and 10). A pressure-sensitive adhesive layer 66 for covering the pressure-sensitive adhesive layer 65 is a release film that is peeled off when the pressure-sensitive adhesive polarizing plate 1 is bonded to the liquid crystal display element.

The supports 2a and 2b of the polarizing plate 2 are made of TAC (triacetyl cellulose). The polarizing plate 2 is produced by stretching a laminate of the support 2a, the polarizer 2c, and the support 2b. The polarizer 2c is polyvinyl acetate (PV
It is prepared by dyeing A) with iodine (I ₂ ). The polarizing plate 2 has a thickness of about 190 μm, and the supports 2a and 2b have a thickness of about 80 μm.
m, and the thickness of the polarizer 2c is about 30 μm.

The protective film 3 is provided to prevent the surface of the polarizing plate 2, that is, the surface of the support 2a from being soiled or scratched when the adhesive polarizing plate 1 is handled, and the support 2a is provided. Is adhered to the surface of the rubber adhesive layer 4 by a rubber-based pressure-sensitive adhesive layer 4. The protective film 3 is formed of, for example, polyester (PET), has a thickness of about 50 μm, and the rubber-based pressure-sensitive adhesive layer 4 has a thickness of about 20 μm. As the rubber-based pressure-sensitive adhesive layer 4, for example, one having the following composition was used.

[0016]

[Table 1]

The release film 66 is provided to protect the adhesive layer 65 for attaching the adhesive polarizing plate 1 to the liquid crystal display element, and is peeled off when attaching the adhesive polarizing plate 1 to the liquid crystal display element. The release film 66 is produced by coating silica (Si) on a polyester (PET) film, for example. The thickness of the release film 66 is about 38
μm. The adhesive layer 65 is, for example, an acrylic adhesive and has a thickness of about 25 μm.

The total thickness of the adhesive polarizing plate 8 is about 21.
It is 0 μm.

As the material of the protective film 3 and the release film 66, polypropylene, polyethylene, acryl, polystyrene, triacetyl cellulose (TAC), polyester sulfone, etc. can be used in addition to the above polyester. The protective film 3 and the release film 66 are, for example, produced by pouring into a mold and have an optically non-axial characteristic. Therefore, in the pressure-sensitive adhesive polarizing plate 1 of the present example, even if both films were not peeled off and the pressure-sensitive adhesive polarizing plate 1 was adhered and mounted on the liquid crystal display element, the polarization degree unevenness in the state in which both films were adhered to Can be inspected. Therefore, even if there is unevenness in the degree of polarization, it is not necessary to reattach the adhesive polarizing plate 1, and the productivity of the liquid crystal display device can be improved. In addition, in order to inspect the polarization degree unevenness, two ideal polarizing plates having no polarization degree unevenness are arranged such that their absorption axes are at right angles, and the adhesive polarization plate 1 to be inspected between them.
Then, the presence or absence of uneven polarization degree is visually inspected with the naked eye.

FIG. 2 is a graph showing the relationship between the high temperature standing time and the adhesive strength to the polarizing plate when the rubber adhesive according to the present invention is used and when the conventional EVA protective film is used. is there.

As is apparent from FIG. 2, when the conventional EVA protective film was used after the high temperature standing process at 70 ° C. for 2 hours, the width was 20 to 30 g / 25 mm to 290 g / 25 mm.
While the width of mm and the adhesive force to the polarizing plate are significantly increased to about 10 to 15 times, the adhesive force to the polarizing plate of the rubber adhesive according to the present invention is changed to 70 g / 25 mm width in the initial stage and after the process. No
The adhesive force to the polarizing plate does not increase.

As described above, in the pressure-sensitive adhesive polarizing plate 1 of this embodiment, since the above-mentioned rubber-based pressure-sensitive adhesive is used to attach the protective film 3 to the polarizing plate 2, the polarizing plate is left even after the high temperature standing step. The adhesive force does not increase at the interface between the second support 2a and the protective film 3. Therefore, the peeling operation of the protective film 3 can be easily performed, and damage to the drive circuit due to the liquid crystal display element or generated static electricity can be suppressed.

The rubber adhesive according to the present invention has an initial adhesive force to the polarizing plate 2 of about 10 at room temperature.
It is desirable that the adhesive strength to the polarizing plate is about 1.5 times the initial adhesive strength when the adhesive polarizing plate 1 is left at about 70 ° C. for about 2 hours. .

FIG. 3 shows the arrangement direction of liquid crystal molecules (eg rubbing direction) on the electrode substrate when the liquid crystal display element 62 according to the present invention is viewed from above, the twist direction of the liquid crystal molecules, and the polarization axis (or absorption) of the polarizing plate. The (axial) direction and the optical axis direction of the member that brings about the birefringence effect are shown, and FIG. 5 is a perspective view of a main part of the liquid crystal display element 62 according to the present invention.

Twisting direction 10 of liquid crystal molecules and twist angle θ
Is a rubbing direction 6 of the alignment film 21 on the upper electrode substrate 11, a rubbing direction 7 of the alignment film 22 on the lower electrode substrate 12, and a positive dielectric anisotropy sandwiched between the upper electrode substrate 11 and the lower electrode substrate 12. It is defined by the type and amount of the optical rotatory substance added to the nematic liquid crystal layer 50 having the property.

In FIG. 4, in order to align the liquid crystal molecules between the two upper and lower electrode substrates 11 and 12 sandwiching the liquid crystal layer 50 so as to form a twisted spiral structure, a transparent upper layer made of, for example, glass is used. The rubbing method, which is a method of rubbing the surfaces of the alignment films 21 and 22 made of an organic polymer resin made of polyimide, for example, in contact with the liquid crystal on the lower electrode substrates 11 and 12 with a cloth in one direction, is used. ing. The rubbing direction at this time, that is, the rubbing direction, the rubbing direction 6 in the upper electrode substrate 11, and the rubbing direction 7 in the lower electrode substrate 12 are the alignment directions of the liquid crystal molecules. The two upper and lower electrode substrates 1 that have been oriented in this way
1 and 12 are made to face each other with a gap d ₁ so that the rubbing directions 6 and 7 intersect each other at approximately 180 to 360 degrees, and the two electrode substrates 11 and 12 are notched for injecting liquid crystal. When a nematic liquid crystal having a positive dielectric anisotropy and having a predetermined amount of an optical rotatory substance is sealed in by adhering with a frame-shaped sealant 52 having a portion 51,
The liquid crystal molecules have a helical molecular arrangement with a twist angle θ in the figure between the electrode substrates. Reference numerals 31 and 32 are transparent upper and lower electrodes made of, for example, indium oxide or ITO (Indium Tin Oxide). A member that produces a birefringence effect on the upper electrode substrate 11 of the liquid crystal cell 60 thus configured (hereinafter referred to as a birefringence member. Fujimura et al., "ST
N-LCD retardation film ", magazine electronic material 1991
(February issue, pages 37-41) 40, and upper and lower polarizing plates 15 and 16 with the member 40 and the liquid crystal cell 60 sandwiched therebetween.

The twist angle θ of the liquid crystal molecules in the liquid crystal 50 can take a value in the range of 180 ° to 360 °, preferably 200 ° to 300 °, but the transmittance-applied voltage curve is turned on near the threshold value. From the practical viewpoint of avoiding the phenomenon that the state becomes an orientation that scatters light and maintaining excellent time division characteristics, the range of 230 to 270 degrees is more preferable. This condition basically makes the response of the liquid crystal molecules to the voltage more sensitive and acts to realize excellent time division characteristics. In order to obtain excellent display quality and the refractive index anisotropy [Delta] n ₁ of the liquid crystal layer 50 a product [Delta] n ₁ of the thickness d ₁
-D ₁ is preferably set in the range of 0.5 μm to 1.0 μm, more preferably 0.6 μm to 0.9 μm.

The birefringent member 40 acts so as to modulate the polarization state of light passing through the liquid crystal cell 60, and converts what could be colored display by the liquid crystal cell 60 alone into black and white display. Thus the birefringent member 40 refractive index anisotropy [Delta] n ₂ and is extremely important product [Delta] n ₂ · d ₂ of a thickness d _2, preferably 0.8μm from 0.4 .mu.m, more preferably 0.5μm To 0.7 μm.

Further, since the liquid crystal display element 62 according to the present invention utilizes the elliptically polarized light due to the birefringence, the polarizing plate 15,
When the uniaxial transparent birefringent plate is used as the birefringent member 40, the relationship between the 16 axes and the liquid crystal alignment directions 6 and 7 of the electrode substrates 11 and 12 of the liquid crystal cell 60 is extremely important. .

The function and effect of the above relationship will be described with reference to FIG. FIG. 3 shows an axis of a polarizing plate, an optical axis of a uniaxial transparent birefringent member when the liquid crystal display device having the configuration of FIG. 4 is viewed from above,
3 shows the relationship between the alignment directions of liquid crystal molecule axes of an electrode substrate of a liquid crystal cell.

In FIG. 4, 5 is the optical axis of the uniaxial transparent birefringent member 40, 6 is the alignment direction of the liquid crystal molecules of the birefringent member 40 and the upper electrode substrate 11 adjacent thereto, and 7 is the lower electrode substrate 12. The liquid crystal alignment direction, 8 is the absorption axis or polarization axis of the upper polarization plate 15, 9 is the absorption axis or polarization axis of the lower polarization plate 16, and the angle α is uniaxial birefringence with the liquid crystal alignment direction 6 of the upper electrode substrate 11. The angle β formed by the optical axis 5 of the member 40 is the angle formed by the absorption axis or polarization axis 8 of the upper polarizing plate 15 and the optical axis 5 of the uniaxial transparent birefringent member 40, and the angle γ is the lower polarizing plate 16. Is the angle between the absorption axis or polarization axis 9 of the liquid crystal and the liquid crystal alignment direction 7 of the lower electrode substrate 12.

Here, how to measure the angles α, β, and γ in this specification will be defined. In FIG. 8, an intersection angle between the optical axis 5 of the birefringent member 40 and the liquid crystal alignment direction 6 of the upper electrode substrate will be described as an example. The intersection angle between the optical axis 5 and the liquid crystal alignment direction 6 is shown in FIG.
As shown in FIG. ₂ , it can be represented by φ ₁ and φ ₂ , but in the present specification, the smaller corner of φ ₁ and φ ₂ is adopted. That is, since φ ₁ <φ ₂ in FIG. 8A, φ ₁ is defined as an intersection angle α between the optical axis 5 and the liquid crystal alignment direction 6,
Since φ ₁ > φ ₂ in FIG. 8B, φ ₂ is defined as an intersection angle α between the optical axis 5 and the liquid crystal alignment direction 6. Of course, either one may be adopted when φ ₁ = φ ₂ .

In the liquid crystal display device according to the present invention, the angles α, β and γ are extremely important.

The angle α is preferably 50 to 90 degrees, more preferably 70 to 90 degrees, the angle β is preferably 20 to 70 degrees, more preferably 30 to 60 degrees, and the angle γ is preferably. It is desirable to set each to 0 to 70 degrees, and more preferably to 0 to 50 degrees.

If the twist angle θ of the liquid crystal layer 50 of the liquid crystal cell 60 is in the range of 180 degrees to 360 degrees, the above angle is satisfied regardless of whether the twist direction 10 is clockwise or counterclockwise. α, β, and γ may be within the above range.

In FIG. 4, the birefringent member 40 is disposed between the upper polarizing plate 15 and the upper electrode substrate 11, but instead of this position, the lower electrode substrate 12 and the lower polarizing plate 16 are provided.
It may be disposed between and. This case corresponds to the case where the entire structure of FIG. 4 is inverted.

Example 1 The basic structure is the same as that shown in FIGS.
In FIG. 5, the twist angle θ of the liquid crystal molecules is 240 degrees, and as the uniaxial transparent birefringent member 40, a liquid crystal cell having a parallel orientation (homogeneous orientation), that is, a twist angle of 0 degree is used. Here, the ratio d / p of the thickness d (μm) of the liquid crystal layer and the helical pitch p (μm) of the liquid crystal material added with the optical rotatory substance was set to 0.67. The alignment films 21 and 22 were formed of a polyimide resin film and used after being rubbed. The alignment film that has been subjected to this rubbing treatment tilts the liquid crystal molecules that are in contact with the alignment film with respect to the substrate surface with a tilt angle (p
The retilt angle) is 4 degrees. The uniaxial transparent birefringent member 4
Δn ₂ · d ₂ of 0 is about 0.6 μm. On the other hand, Δn ₁ · d ₁ of the liquid crystal layer 50 having a structure in which liquid crystal molecules are twisted by 240 degrees is about 0.8 μm.

At this time, by setting the angle α to about 90 degrees, the angle β to about 30 degrees, and the angle γ to about 30 degrees, the voltage applied to the liquid crystal layer 50 via the upper and lower electrodes 31 and 32 is increased. When the voltage is below the threshold value, light non-transmission, that is, black display, and when the voltage exceeds a threshold value, light transmission, that is, white and black display, can be realized. In addition, the axis of the lower polarizing plate 16 is 50
When rotated 90 degrees from 90 degrees, white display was realized when the voltage applied to the liquid crystal layer 50 was below the threshold value, and black when the voltage was above the threshold value, which was the reverse of the above.

FIG. 6 shows a change in contrast during time-division driving at 1/200 duty when the angle α is changed in the configuration of FIG. Although the contrast was extremely high when the angle α was in the vicinity of 90 degrees, the contrast decreased as the angle deviated. Moreover, when the angle α is small, both the lighting part and the non-lighting part are bluish, and when the angle α is large, the non-lighting part is purple and the lighting part is yellow, and in any case black and white display is impossible. Similar results are obtained for the angle β and the angle γ, but in the case of the angle γ, as described above, when the image is rotated from 50 degrees to 90 degrees, the black and white display is reversed.

Example 2 The basic structure is similar to that of Example 1. However, the liquid crystal layer 50
The liquid crystal molecule has a twist angle of 260 degrees, and Δn ₁ · d ₁ is about 0.
The difference is 65 μm to 0.75 μm. Δ of the parallel alignment liquid crystal layer used as the uniaxial transparent birefringent member 40
n ₂ · d ₂ is about 0.58 μm as in the first embodiment. The ratio of the thickness d ₁ (μm) of the liquid crystal layer to the helical pitch p (μm) of the nematic liquid crystal material to which the optically active substance is added is d / p =
It was set to 0.72.

At this time, by setting the angle α to about 100 degrees, the angle β to about 35 degrees, and the angle γ to about 15 degrees, the monochrome display similar to that of the first embodiment can be realized. It is also similar to the first embodiment in that a reverse black-and-white display is possible by rotating the axial position of the lower polarizing plate from the above value by 50 to 90 degrees. The tendency for the deviations of the angles α, β, and γ is almost the same as that of the first embodiment.

In each of the above embodiments, a parallel alignment liquid crystal cell having no twist of liquid crystal molecules was used as the uniaxial transparent birefringent member 40, but rather a liquid crystal layer in which liquid crystal molecules are twisted by about 20 to 60 degrees is used. There is less color change depending on the angle. Like the above-mentioned liquid crystal layer 50, this twisted liquid crystal layer is formed by sandwiching liquid crystal between a pair of transparent substrates that have been subjected to the alignment treatment so that the alignment treatment directions intersect a predetermined twist angle. It In this case, the bisected angle of the two orientation treatment directions sandwiching the twisted structure of the liquid crystal molecules may be treated as the optical axis of the birefringent member. A transparent polymer film may be used as the birefringent member 40 (uniaxially stretched film is preferable at this time). In this case, PET (polyethylene terephthalate), acrylic resin film and polycarbonate are effective as the polymer film.

Further, although the single birefringent member is used in the above embodiments, in addition to the birefringent member 40 in FIG. 4, another birefringent member is provided between the lower electrode substrate 12 and the lower polarizing plate 16. It is also possible to insert a bending member. In this case, Δn ₂ · d ₂ of these birefringent members should be readjusted.

Example 3 The basic structure is the same as in Example 1. However, as shown in FIG. 7, red, green, and blue color filters 3 are formed on the upper electrode substrate 11.
By providing the light shielding film 33D between the filters 3R, 33G, 33B and the filters, multicolor display is possible.

Incidentally, in FIG. 7, each filter 33
On the R, 33G, 33B and the light shielding film 33D, a smoothing layer 23 made of an insulating material is formed in order to reduce the influence of these irregularities, and then an upper electrode 31 and an alignment film 21 are formed.

Example 4 A liquid crystal display module 63 in which a liquid crystal display element 62 according to Example 3, a drive circuit for driving the liquid crystal display element 62, and a light source are compactly integrated.

FIG. 8 shows an exploded perspective view thereof.
The IC 34 for driving the liquid crystal display element 62 is mounted on a frame-shaped printed board 35 having a window portion for fitting the liquid crystal display element 62 in the center. The printed circuit board 35 in which the liquid crystal display element 62 is fitted is fitted in the window portion of the frame-shaped body 42 formed by plastic molding, the metal frame 41 is overlapped on this, and the claws 43 are formed on the frame-shaped body 42. The frame 41 is fixed to the frame-like body 42 by bending it inside the notch 44.

A cold cathode fluorescent lamp 36 arranged at the upper and lower ends of the liquid crystal display element 62, a light guide 37 made of an acrylic plate for uniformly irradiating the liquid crystal display cell 60 with light from the cold cathode fluorescent lamp 36, A reflecting plate 38 formed by applying a white paint to a metal plate and a milky white diffusing plate 39 for diffusing light from the light guide 37 are fitted into the window portion from the back side of the frame-shaped body 42 in the order of FIG. Be done. An inverter power supply circuit (not shown) for turning on the cold cathode fluorescent lamp 36 is provided with a recess (not shown) provided on the right side rear portion of the frame-shaped body 42. The recess 45 of the reflector 38 is provided.
It is in a position facing. ). Diffusion plate 39,
The light guide 37, the cold cathode fluorescent lamp 36, and the reflector 38 are fixed by bending a tongue piece 46 provided on the reflector 38 into an edge 47 provided on the frame-shaped body 42.

Embodiment 5 The liquid crystal display module 63 according to Embodiment 4 is used in the display section of a laptop personal computer.

FIG. 9 is a block diagram thereof, and FIG.
FIG. 0 shows a diagram mounted on the laptop personal computer 64. The result calculated by the microprocessor 49 is to drive the liquid crystal display module 63 by the drive IC 34 via the control LSI 48.

As described above, according to the above-described embodiment, it is possible to realize the field effect liquid crystal display device which has excellent time-division driving characteristics and enables black and white and multicolor display.

Although the present invention has been specifically described based on the embodiments, the present invention is not limited to the above embodiments, and it is needless to say that various modifications can be made without departing from the scope of the invention. . For example, the adhesive polarizing plate is not limited to the configuration, material, thickness and the like shown in FIG. 1 and can be applied to various things. Further, in the above-mentioned embodiment, an example in which the present invention is applied to a simple matrix type liquid crystal display device is shown, but it goes without saying that the present invention can also be applied to an active matrix type liquid crystal display device.

[0053]

As described above, in the pressure-sensitive adhesive polarizing plate of the present invention, the adhesive force does not increase at the interface between the support of the polarizing plate and the protective film even after the high temperature standing step, so that the peeling work of the protective film is performed. Can be easily performed and damage to the drive circuit due to the liquid crystal display element or generated static electricity can be suppressed.

[Brief description of drawings]

FIG. 1 is a partial cross-sectional view of an adhesive polarizing plate according to an example of the present invention.

FIG. 2 is a diagram showing a relationship between a high-temperature standing time and a polarizing plate adhesive force when a rubber-based pressure-sensitive adhesive according to the present invention is used and when a conventional EVA protective film is used.

FIG. 3 is an explanatory diagram showing a relationship among an alignment direction of liquid crystal molecules, a twisting direction of liquid crystal molecules, a direction of an axis of a polarizing plate, and an optical axis of a birefringent member in a first embodiment of a liquid crystal display device according to the present invention. Is.

FIG. 4 is an exploded perspective view of essential parts of a first embodiment of a liquid crystal display device according to the present invention.

FIG. 5 is an explanatory diagram showing the relationship between the twist direction of liquid crystal molecules, the direction of the axis of the deflecting plate, and the optical axis of the birefringent member in the second embodiment of the liquid crystal display device according to the present invention.

FIG. 6 is a graph showing contrast and transmitted light color-crossing angle α characteristics of the first embodiment of the liquid crystal display device according to the present invention.

FIG. 7 is an explanatory diagram showing the relationship among the alignment direction of liquid crystal molecules, the twisting direction of liquid crystal molecules, the direction of the axis of the deflecting plate, and the optical axis of the birefringent member in the third embodiment of the liquid crystal display device according to the present invention. Is.

FIG. 8 is an exploded perspective view of a liquid crystal display module according to the present invention.

FIG. 9 is a diagram for explaining how to measure intersection angles α, β, and γ.

FIG. 10 is a partially cutaway perspective view of an upper electrode substrate portion of an embodiment of the liquid crystal display device according to the present invention.

FIG. 11 is a block diagram of an embodiment of a laptop personal computer according to the present invention.

FIG. 12 is a perspective view of an embodiment of a laptop computer according to the present invention.

[Explanation of symbols]

1 ... Adhesive polarizing plate, 2 ... Polarizing plate, 2a, 2b ... Support, 2
c ... Polarizer, 3 ... Protective film, 4 ... Rubber-based adhesive layer,
65 ... Adhesive layer, 66 ... Release film.

Claims (2)

[Claims] 1. An adhesive polarizing plate comprising a polarizing plate and a protective film thereof, wherein an adhesive layer for adhering the protective film to the polarizing plate is interposed between the two, and the polarizing plate is at room temperature. Initial adhesion is about 10-1
00g / 25mm width, and the adhesive polarizing plate about 70 ℃
A pressure-sensitive adhesive polarizing plate comprising, as the pressure-sensitive adhesive layer, a rubber-based pressure-sensitive adhesive whose change in adhesive strength when left for about 2 hours is within about 1.5 times the initial adhesive strength. 2. The protective film is transparent polyester,
The pressure-sensitive adhesive polarizing plate according to claim 1, which is made of polypropylene or polyethylene.