WO2008026374A1

WO2008026374A1 - Polarizing plate, polarizing plate manufacturing method, display panel and display element

Info

Publication number: WO2008026374A1
Application number: PCT/JP2007/063352
Authority: WO
Inventors: Nobuhiko Nakai
Original assignee: Sharp Kabushiki Kaisha
Priority date: 2006-08-29
Filing date: 2007-07-04
Publication date: 2008-03-06

Abstract

Provided are a large polarizing plate having excellent display quality, a polarizing plate manufacturing method for surely obtaining such polarizing plate, and a display panel applicable to large screen sizes. A large polarizing plate (2) is provided by connecting a plurality of small polarizing plates (2a, 2b) in the plane direction of the small polarizing plates (2a, 2b) so that polarizing axes (Pa, Pb) of the small polarizing plates (2a, 2b) are identical. A polarizing plate (1) is configured by integrally laminating the large polarizing plate on the surface of a temporary film (3), i.e., a supporting body.

Description

Specification

Polarizing plate, manufacturing method of polarizing plate, display panel and display element

Technical field

TECHNICAL FIELD [0001] The present invention relates to a polarizing plate that can be enlarged, a method for producing the polarizing plate, a display panel using a polarizing plate suitably used for a large liquid crystal display device, and the like, and a display element.

Background art

[0002] Liquid crystal display elements are widely used in televisions and the like. A liquid crystal display element has a power of two substrates with a liquid crystal layer sandwiched between them, and a liquid crystal display panel, which is an optical element that can electrically control the amount of transmitted or reflected light, is integrated with a drive circuit and backlight. Configured.

[0003] For example, in a transmissive liquid crystal display panel, a polarizing plate having a function of transmitting only a specific polarization component with respect to incident light is laminated on the surfaces of two transparent substrates. The two polarizing plates are arranged so that their polarization axes are orthogonal to each other on the incident light side and the outgoing light side of the liquid crystal layer.

[0004] A polarizing plate is made by laminating a base film on both the front and back sides of a polarizing film that is oriented by adding an iodine compound to a polybulal alcohol (PVA) film, and having an adhesive layer and a release film on one side. Those which are sequentially laminated are widely used. The base film supports the polarizing film and is provided for improving the reliability of the polarizing plate. Since the base film of the polarizing plate is excellent in optical properties and uniformity, is highly reliable and inexpensive, a triacetyl cellulose (TAC) film is generally used!

[0005] In recent years, display devices such as televisions have become larger in screen. In order to increase the size of the display device, it is necessary to increase the size of optical components such as polarizing plates. However, the TAC film used as the base film of the polarizing plate is supplied to the factory! The maximum size of the polarizing plate that can be obtained from the maximum width of the original film is up to the 65-inch class. A single-size polarizing plate exceeding the size of the class did not exist.

[0006] In order to produce a large polarizing plate, it is required to increase the size of the TAC film raw material.

To increase the size of the TAC film, it is necessary to increase the size of the original fabric while maintaining the current film characteristics. To supply large-scale films industrially Since it takes time to solve various technical problems, it is impossible to supply a large TAC film in a short time.

[0007] By the way, as a large-sized liquid crystal display element, four liquid crystal panels are arranged side by side to form a single liquid crystal panel, and a reinforcing substrate such as glass or acrylic resin is provided on the front side and the back side of the liquid crystal panel. A liquid crystal display device is known in which four polarizing plates are attached to a reinforcing substrate on the back side, and one polarizing plate is attached to the reinforcing substrate on the front side (Japanese Unexamined Patent Application Publication No. 2004-93). (Ref. No. 825).

Disclosure of the invention

Problems to be solved by the invention

[0008] By using the method described in Japanese Patent Application Laid-Open No. 2004-93825, it is conceivable to make a large polarizing plate by attaching four polarizing plates to a reinforcing substrate. Specifically, in this method, a plurality of thin and film-like polarizing plates are sequentially pasted on a single reinforcing base material that is hard and has a material strength such as glass and acrylic resin. Applying a thin film to the surface of such a hard substrate one by one with great force, it takes a lot of work to apply the film, and there is a gap or gap between the films. However, it was extremely difficult to paste it neatly and make a single large polarizing plate. If a gap is formed, shifted, or overlaps at the joint between the polarizing plates, polarized light is not generated, and the display quality of the display device is greatly reduced.

[0009] Even if the gap is small, microscopically there is an air layer at the joint, so reflection occurs due to the difference in refractive index between the air layer at the joint and the polarizing plate, and the joint is noticeable. There was a problem of end.

[0010] In view of the above situation, the problem to be solved by the present invention is to provide a large polarizing plate excellent in display quality, and to provide a method for producing a polarizing plate capable of reliably obtaining the polarizing plate. It is another object of the present invention to provide a display panel and a display element that can cope with a large screen.

Means for solving the problem

In order to solve such problems, the polarizing plate of the present invention has a plurality of small polarizing plates connected to the surface of a temporary film as a support so that the polarizing axes are the same. The gist is that the large polarizing plate is integrated.

In the polarizing plate of the present invention, the temporary film can be formed in the same size as the large polarizing plate. The temporary film can be formed as a single film or a plurality of film forces.

[0013] In the polarizing plate of the present invention, the joint between the small polarizing plates is processed to prevent misalignment, or the small polarizing plate is laminated at least on the polarizing film and on the front and back of the polarizing film. It can be formed from a base film, an adhesive layer laminated on one base film side, and a release film. The base film is preferably a triacetyl cellulose film.

[0014] Further, it is preferable that a transparent resin portion is formed in the gap between the joint portions. More preferably, it is desirable that the refractive index of the transparent resin part and the small polarizing plate are equal.

[0015] The method for producing a polarizing plate of the present invention comprises forming a large polarizing plate by arranging a plurality of small polarizing plates and connecting the small polarizing plates together in a plane direction, and a temporary substrate serving as a support on the large polarizing plate. The gist is that the films are laminated and integrated into a single polarizing plate. In the above production method, it is preferable to use a temporary film provided with an adhesive layer made of a releasable adhesive.

[0016] The display panel of the present invention is characterized in that the above polarizing plates are laminated. The gist of the display element of the present invention is that the above-described display panel is used.

The invention's effect

[0017] According to the present invention, the surface of the temporary film as the support is integrated with the large polarizing plate in which a plurality of small polarizing plates are connected in the plane direction. A film-like soft polarizing plate assembly can be attached to the support surface of a soft material compared to a glass plate such as a film. Compared to the case of bonding, it is easier to bond the small polarizing plates together, and the force is also less likely to cause problems such as overlap, gaps, and misalignment at the joints between the small polarizing plates. Thus, a large polarizing plate with excellent display quality can be easily obtained. [0018] Further, by forming a transparent resin portion at the joint portion of the small polarizing plate, reflection at the interface between the small polarizing plate and the air layer of the joint portion can be reduced, and the joint portion can be made inconspicuous. Furthermore, by making the refractive index of the transparent resin portion of the bonded portion substantially the same as the refractive index of the small polarizing plate, reflection at the interface can be further reduced and the bonded portion can be made less noticeable. Especially, it is effective for bright !, many screens, television images, etc.

[0019] As described above, since a large polarizing plate excellent in display quality can be obtained by laminating a small polarizing plate, even if the screen of the television is further rapidly increased, the polarizing plate is immediately increased in size. Therefore, it is possible to quickly supply a large display panel while maintaining excellent display quality.

Brief Description of Drawings

FIG. 1 is a perspective view showing an appearance of an example of a polarizing plate of the present invention.

2 is a cross-sectional view of the polarizing plate of FIG. 1 taken along the line BB.

3 is a cross-sectional view of a small polarizing plate 2a used for the polarizing plate of FIG.

FIG. 4 (a) to (c) are plan views showing other embodiments of polarizing plates.

[FIG. 5] (a) to (c) are plan views showing other embodiments of the polarizing plate.

[FIG. 6] (a) to (d) are process charts showing an example of a polarizing plate production method.

FIG. 7 is a plan view showing a joining process of a small polarizing plate.

[FIG. 8] (a) is a plan view showing a large polarizing plate in which unevenness for alignment is provided at the joint portion, and (b) is an enlarged view of the vicinity of the unevenness for alignment in (a).

FIG. 9 is a layout diagram showing a schematic configuration of a liquid crystal display element as an example of a display device using the display panel of the present invention.

[FIG. 10] (a) and (b) are schematic cross-sectional views showing another example of bonding a small polarizing plate and a temporary film.

FIG. 11 is an enlarged cross-sectional view for explaining the reflection at the interface between the air layer and the small polarizing plate at the junction of the small polarizing plate.

[FIG. 12] (a) and (b) are enlarged cross-sectional views for explaining the formation of a transparent resin portion at the joining portion of a small polarizing plate.

[Fig. 13] (a) Enlarged cross-sectional view of a bonded polarizing plate with a transparent resin part formed at the bonded portion of a small polarizing plate (B) is an enlarged cross-sectional view of a display panel in which a transparent resin portion is formed at a small polarizing plate and its joint.

FIG. 14 is a schematic view of a liquid crystal display device as another example of a display element using the panel of the present invention.

[FIG. 15] (a) to (d) are diagrams showing the arrangement of the junctions of the small polarizing plates.

FIG. 16 is a diagram showing the center part of the screen of the display panel.

BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a perspective view showing an example of the polarizing plate of the present invention, and FIG. 2 is a cross-sectional view taken along line BB in FIG. As shown in FIGS. 1 and 2, the polarizing plate 1 of the present invention has a plurality of small polarizing plates 2a and 2b, so that the polarizing axes Pa and Pb of the small polarizing plates 2a and 2b are the same. A large polarizing plate 2 connected in the plane direction of the small polarizing plates 2a and 2b is laminated and integrated on the surface of a temporary film 3 as a support.

As shown in FIG. 2, the large polarizing plate 2 is laminated and integrated with the temporary film 3 via an adhesive layer 4 provided on the surface of the temporary film 3. Each of the small polarizing plates 2a and 2b and the polarizing plate 1 is formed in a square shape.

FIG. 3 is a cross-sectional view of a small polarizing plate 2a used for the polarizing plate of FIG. The small polarizing plate 2a and the small polarizing plate 2b are structurally the same polarizing plate, and the small polarizing plate 2b has the same layer structure as the small polarizing plate 2a. The small polarizing plate 2a and the small polarizing plate 2b are formed in the same size.

As shown in FIG. 3, a polarizing plate 2a shown in FIG. 1 includes a polarizing film 21, base films 22 and 23 laminated on both front and back surfaces of the polarizing film 21, and one base film 22 side. It is formed at least from the laminated adhesive layer 24 and the release film 25.

[0025] As the small polarizing plates 2a and 2b, polarizing plates having a known material strength can be used. The polarizing film 21 is a polybulal alcohol (PVA) film added with iodine or a dichroic dye, uniaxially stretched and oriented in one direction. The base films 22 and 23 are preferably used because they are excellent in triacetyl cellulose (TAC) film strength, optical characteristics, reliability, and the like, and are inexpensive.

For example, the small polarizing plates 2a and 2b are obtained by the following method. First is the film feeder A roll-shaped PVA raw film is supplied, dyed with iodine or dichroic dye using a processing device, uniaxially stretched with a stretching device, then heat-treated and applied to both the front and back surfaces of the stretched polarizing film. Polarizing plate rolls can be obtained by laminating TAC films with a laminator and winding them with a winder. This polarizing plate roll is cut into a predetermined size according to the liquid crystal panel to be used, and single-sheet small polarizing plates 2a and 2b are obtained. Usually, a polarizing plate roll is formed such that the polarization axis is parallel to the longitudinal direction.

[0027] The temporary film 3 is used as a support for supporting the large polarizing plate 2 in which the small polarizing plates 2a and 2b are joined together to form a large polarized light until it is attached to the surface of the display panel. If the film can hold the shape of the plate 2 temporarily, Since the temporary film 3 is normally peeled and removed after the polarizing plate 1 is laminated on the display panel, no particular optical characteristics are required. As the temporary film 3, a polyethylene terephthalate (PET) film is preferred because a large single-piece film can be easily obtained, satisfies the above physical properties such as shape retention, and is inexpensive.

[0028] The temporary film 3 may be continuously laminated without being peeled off after the polarizing plate 1 is attached to the display panel. Thus, when the temporary film 3 is laminated on the large polarizing plate 2 even after being attached to the display panel, it can be used as a protective film for the display panel. In this case, it is preferable that the temporary film 3 is made of a film that is not easily damaged or a protective layer is provided on the surface of the temporary film 3.

[0029] The adhesive layer 4 for integrally bonding the temporary film 3 and the small polarizing plates 2a and 2b can maintain the state of the large polarizing plate 2 when the small polarizing plates 2a and 2b are attached to the temporary film 3. It only needs to have a moderate adhesive strength. If a releasable adhesive is used as the material for the adhesive layer 4, the temporary film 3 can be easily peeled off after the polarizing plate 1 is adhered to the liquid crystal panel, and the adhesive remains. There will be no malfunctions.

[0030] When the polarizing film 1 is attached to the liquid crystal panel and then the temporary film 3 is attached without peeling off, and when used as a protective film, the adhesive layer 4 has sufficient adhesive strength as a protective film. It is preferable to have it.

[0031] The polarizing plate 1 of the embodiment shown in FIG. 1 has a joint portion 11 between the small polarizing plates 2a and 2b. And are formed so as to be parallel to the polarization axes Pa and Pb. That is, the polarizing plate 1 is formed by connecting a plurality of small polarizing plates 2a and 2b in a plane direction parallel to the polarization axis direction. 4 (a) to (c) and FIGS. 5 (a) to (c) are plan views showing other embodiments of the polarizing plate. The polarizing plate of the present invention is not limited to the embodiment shown in FIG. 1, and can be formed in the embodiments shown in FIGS. 4 (a) to (c) and FIGS. 5 (a) to (c).

[0032] The polarizing plate 1 shown in FIG. 4 (a) has two small polarizing plates 2c and 2d having polarization axes Pc and Pd, respectively, and left and right so that the junction 11 is orthogonal to the polarization axes Pc and Pd. They are connected side by side. The polarizing plate 1 shown in Fig. 4 (b) has two small polarizing plates 2e and 2f with polarization axes Pe and Pf, respectively, and the polarization axes Pe and Pf are 45 degrees counterclockwise in the figure with respect to the junction 11. They are joined side by side so that they cross at an inclined angle. The polarizing plate 1 shown in Fig. 4 (c) has two small polarizing plates 2g and 2h with polarization axes Pg and Ph, respectively, and the polarization axes Pg and Ph with respect to the junction 11 are 45 degrees clockwise in the figure. They are joined side by side so that they cross at an angle.

[0033] The polarizing plate 1 shown in FIG. 1 has a force obtained by joining two small polarizing plates 2a and 2b arranged on the left and right sides, and as shown in FIG. 5 (a), the polarization axes Pi and Pj respectively. The two small polarizing plates 2i and ¾ having the upper and lower sides may be joined in the up and down direction so that the polarization axes Pi and Pj are parallel to the joining portion 11. Although not particularly illustrated, when two small polarizing plates are joined in the vertical direction, they may be joined side by side so that the joining portion 11 and the polarization axis are orthogonal or crossed. Further, three or more small polarizing plates may be arranged side by side in the vertical direction and joined. In the present invention, the vertical direction and the horizontal direction of the arrangement of the small polarizing plates mean the vertical direction or the horizontal direction when viewing the display panel image when the polarizing plate 1 is a display panel. To tell.

[0034] In addition, the polarizing plate 1 shown in FIG. 1 is formed by joining two small rectangular polarizing plates of the same size, but as shown in FIG. 5 (b), two polarizing plates with different widths are used. The polarizing plates 2k and 21 may be joined. In this case, the joint portion 11 is shifted from the center line 12 in the width direction that bisects the polarizing plate.

In the polarizing plate 1 of the present invention, the plurality of small polarizing plates to be bonded is not limited to two, and three or more small polarizing plates may be bonded. For example, as shown in Fig. 5 (c), three small polarizing plates 2m, 2n, and 2p having polarization axes Pm, Pn, and Pp are polarized with respect to the junctions 11 and 13 in the horizontal direction. The polarizing plate 1 may be configured by arranging and bonding so that the axes Pm, Pn, and Pp are parallel.

In the polarizing film shown in FIG. 1, the temporary film 3 has a single film force, but may also have a plurality of divided film forces. In the polarizing plate shown in FIG. 1, the temporary film 3 is formed in the same size as the large polarizing plate 2, but may be formed in a size different from that of the large polarizing plate 2. In addition, the temporary film 3 should be formed smaller than the large polarizing plate 2 and partially so as to cover at least the junction between the small polarizing plates.

[0037] As shown in FIG. 1, if the temporary film 3 is formed to have the same size as the large polarizing plate 2, the large polarizing plate 2 and the temporary film 3 are pressed with a roller or the like when they are laminated. In the case of laminating, since there is no unevenness at the interface between them, there is no risk of air entering the laminating surface, and a uniform laminate can be obtained. In addition, when the temporary leaf film 3 is used as a protective film without being peeled after the polarizing plate 1 is laminated on the display panel, the temporary film 3 needs to be formed in a size that covers the entire surface of the large polarizing plate 2.

6 (a) to 6 (d) are process diagrams showing an example of a polarizing plate manufacturing method. Hereinafter, the manufacturing method of the polarizing plate of this invention is demonstrated. First, as shown in FIG. 6 (a), the small polarizing plates 2a and 2b are placed on the flat surface 10, and the release film 25 (not shown) side is on the lower side (flat surface 10 side). In the junction 11 between the small polarizers 2a and 2b, align the junction 11 so that the junction ends of the small polarizers 2a and 2b do not overlap, move apart, or shift.

[0039] As shown in Fig. 10 (a) and (b), the vacuum pump 54 and the suction-on Z-off switching valve 50 are provided on the flat surface 10 so that the suction is turned off during the alignment and bonding is performed. When the part 11 force S fits together, adsorption may be turned on so that the small polarizing plates 2a and 2b can be fixed.

Next, as shown in FIG. 6 (b), the temporary film 3 provided with the adhesive layer 4 is laminated so that the adhesive layer 4 side is in contact with the surface of the large polarizing plate 2. Integrate plate 2 (see (c) in the figure). For this lamination and integration, for example, means for pressing with a roller from above the laminated body of the large polarizing plate 2 and the temporary film 3 can be used.

[0041] When a temporary film is laminated by bonding in FIG. They can be joined together under pressure, etc., or they can be bonded together by bending the temporary film so that the force at one end gradually contacts the other end!

[0042] For example, when the small polarizing plates 2a and 2b that are not joined together are directly bonded to an adherend that has a hard flat surface force such as a glass plate, the small polarizing plates 2a and 2b may be bonded at a time. Can not. Therefore, the small polarizing plates 2a and 2b are sequentially bonded. In order to stick each small polarizing plate 2a, 2b to the adherend sequentially, first attach the small polarizing plate 2a to the adherend, and then another small polarizing plate on the edge of the small polarizing plate 2a. It must be arranged and pasted so that the edges of 2b are aligned without gaps. At this time, a pressure-sensitive adhesive (adhesive) is usually present on the surface of each small polarizing plate 2a, 2b or adherend. Therefore, the alignment between the edge of the small polarizing plate 2a bonded to the adherend and the edge of the polarizing plate 2b bonded to the adherend needs to be performed in a non-contact state. Therefore, the positioning of the small polarizing plate 2b cannot be performed with high accuracy.

[0043] In addition, the adhesive force of the adhesive layers 24 of the small polarizing plates 2a and 2b is usually set to be strong so that the polarizing plate once applied is not peeled off. I can't. Therefore, the alignment of the joint 11 of the small polarizing plates 2a and 2b is a very difficult task that cannot be undone.

[0044] On the other hand, according to the polarizing plate 1 in which a plurality of small polarizing plates 2a and 2b are laminated on the temporary film 3 of the present invention, the alignment of the small polarizing plates 2a and 2b is the end of each other. Can be done in direct contact. Therefore, it is possible to precisely align the small polarizing plates.

[0045] Further, when a plurality of small polarizing plates are directly attached to the adherend, it is necessary to repeat positioning in a non-contact state by the number of small polarizing plates. The greater the number of non-contact positioning, the lower the bonding accuracy. On the other hand, when the large polarizing plate 2 with the small polarizing plates 2a and 2b bonded and the polarizing plate 1 in which 3 is laminated and integrated on the temporary film are attached to the adherend, the non-contact positioning is once performed. Just do it. Accordingly, positioning accuracy is improved because the number of times of positioning in a non-contact state is minimized.

In addition, as shown in FIG. 10 (a), in a state where the temporary film 3 is adsorbed to the upper plate 57 having an adsorbing function, one end of the temporary film and one end outside the small polarizing plate 2a or 2b Further, it may be adhered. At this time, it is better to set the adsorbing force of the upper plate 57 to be weaker than the adhering force of the adhesive layer 4. Also, as shown in Fig. 10 (b), the temporary film 3 can be used by adsorbing it to the upper plate 59 having an arc. Thus, when the adhesive layer 4 is provided on the surface in advance and the temporary film 3 is used, the trouble of forming the adhesive layer 4 can be saved, so that the lamination and integration can be easily performed.

[0047] As shown in FIG. 10 (b), the temporary polarizing film 3 is laminated and integrated with the large polarizing plate 2 in a state where the temporary film 3 is adsorbed by the upper plate 59 having an arc, as follows. One end of the temporary film 3 is brought close to one end of the large polarizing plate 2 while being aligned in a non-contact state. In this way, by bringing one end of the temporary film 3 into contact with one end of the large polarizing plate 2, the temporary film 3 and the large polarizing plate 2 are partially bonded via the adhesive layer 4. Subsequently, by gradually reducing the inclination of the upper plate 59 having an arc for adsorbing and supporting the temporary leaf film 3, the temporary film 3 is gradually brought into contact with the other end side of the large polarizing plate 2 by directing force. . Then, the portion of the temporary film 3 adhered to the large polarizing plate 2 is peeled off from the upper plate 59 having an arc, and is gradually laminated and integrated with the large polarizing plate 2.

[0048] In this way, the temporary film 3 is laminated on the large polarizing plate 2 in which the end surfaces of the small polarizing plates 2a and 2b are in direct contact with each other and aligned so as to be aligned without gaps on the flat surface 10 in advance. By doing so, it is possible to accurately align the joint portion 11 of the small polarizing plates 2a and 2b.

[0049] In addition, if the adhesive force of the adhesive layer 4 of the temporary film 3 is set so that the temporary film 3 and the large polarizing plate 2 can be repeatedly bonded and peeled off, the large polarizing plate 2 and the tempo are temporarily assumed. If the gap between the small polarizers 2a and 2b is created in the process of laminating the rally film 3 and the small polarizers 2a and 2b are wrinkled, the process can be easily repeated. be able to.

[0050] As described above, since the laminated integral film of the temporary film 3 and the large polarizing plate 2 is a film-to-film adhesion, it can be easily and cleanly adhered as compared with the case where the film is adhered to a hard glass plate. it can.

[0051] As shown in FIG. 6 (d), the polarizing plate 1 is obtained by being separated from the flat surface 10. Polarizing plate 1 has adhesive layer 4 with small polarizing plates 2a and 2b supported by temporary film 3. And integrated with Temporary Film 3. Further, since the polarizing plate 1 is provided with the release film 25 on the surface of the small polarizing plates 2a and 2b, a plurality of polarizing plates 1 can be stacked and stored.

FIG. 7 is a plan view showing a small polarizing plate bonding step. When joining the small polarizing plates 2a and 2b, as shown in FIG. 7, after using the L-shaped ruler 13 to place the small polarizing plate 2a along the ruler, the small polarizing plate 2b Place and join the plate 2a and the ruler 13 so that they are pressed against each other. In this way, the joining portion 11 of the small polarizing plates 2a and 2b can be neatly aligned.

[0053] Fig. 8 (a) is a plan view showing a large polarizing plate in which alignment irregularities are provided in the joint portion, and (b) is an enlarged view of the vicinity of the alignment irregularities in (a). The polarizing plate 1 of the present invention can be processed to prevent misalignment at the joint portion that becomes a joint between the small polarizing plates. The large polarizing plates shown in FIGS. 8 (a) and 8 (b) are provided with alignment irregularities 6 as an example of processing for preventing displacement. As shown in the figure, the alignment irregularity 6 is provided with a non-display area 15 that is outside the display area 14 of the image at the periphery of the display panel at the junction 11 of the two small polarizing plates 2a and 2b. Yes.

[0054] As shown in FIG. 8 (b), the alignment unevenness 6 is such that the joint portion of one small polarizing plate 2a is a convex portion 6a and the joint portion of the other small polarizing plate 2b is a concave portion 6b. When the joining portions 11 are brought together, the convex portion 6a is formed so as to fit into the concave portion 6b. In addition, the convexity 6 for alignment is such that when the convex part 6a is fitted in the concave part 6b, the small polarizing plates 2a and 2b do not move up and down and left and right! / It is farther and smaller than the width of the part! It has a wedge shape and is formed so that it is difficult to shift vertically and horizontally.

[0055] Also. As shown in FIG. 8 (a), the alignment irregularities 6 may be provided at two locations, which are the non-display area 15 above and below the joint portion 11. In order to perform processing for preventing misalignment of the alignment unevenness 6 and the like, for example, the polarizing plate roll force may be cut into a predetermined shape when cutting the polarizing plate of a single sheet. In the polarizing plate 1, if a misalignment, overlap, gap, etc. occurs at the junction between the small polarizing plates, there is an optical adverse effect such as no generation of polarized light. Improving the accuracy of joints by applying a process to prevent misalignment is effective in improving the display quality. FIG. 9 is a layout diagram illustrating a schematic configuration of a liquid crystal display element as an example of a display device using the display panel of the present invention. Hereinafter, the display panel of the present invention will be described. The liquid crystal display element 30 in FIG. 9 includes a liquid crystal display panel 31 and a backlight 32 provided on the back side of the liquid crystal display panel 31.

[0057] The liquid crystal display panel 31 is a transmissive display panel, and a color filter substrate 34 having an alignment film, a common electrode, a color filter, etc. 36 provided on the surface of one transparent substrate, and the surface of the other transparent substrate. An array substrate 35 provided with TFTs, display electrodes, alignment films, etc. 37, a liquid crystal layer 33 sandwiched between the pair of substrates 34 and 35, and a pair of layers laminated on the incident light side and the outgoing light side It comprises polarizing plates 38 and 39. The polarizing plates 38 and 39 are arranged so that their polarization axes are perpendicular to each other. For the polarizing plates 38 and 39, the polarizing plate 1 of the present invention joined together is used.

[0058] In the liquid crystal display panel 31, the polarizing plate 1 may be used for only one of the polarizing plate 39 on the incident light side and the polarizing plate 38 on the outgoing light side. When the polarizing plate 1 connected to the polarizing plate 39 on the incident light side is used, since the polarizing plate 1 is positioned on the back side with respect to the liquid crystal layer 33, there is an advantage that the joint becomes inconspicuous.

Further, as shown in FIG. 14, a selective reflection polarizing layer 80 may be disposed between the polarizing plate 39 on the incident light side and the backlight 32. As the selective reflection polarizing layer 80, for example, a brightness enhancement film “DBEF” (manufactured by 3M) can be used. The arrows 81 and 82 and the point 83 shown on the right side of FIG. 14 show an example of the arrangement of the polarization axes of the polarizing plate and the selective reflection polarizing layer. Here, the polarization axis indicates the polarization direction of the passing polarized light, that is, the vibration direction of the electric field. Arrows 81 and 82 indicate that the electric field oscillates in the left-right direction, which are the polarization axes of the polarizing plate 39 and the selective reflection polarizing layer 80, respectively. A point 83 indicates that the electric field is oscillating in a direction perpendicular to the paper surface, and is the polarization axis of the polarizing plate 38. If the direction of the polarizing axis 81 of the polarizing plate 39 on the incident light side formed by joining the small polarizing plates and the direction 82 of the polarizing axis of the selective reflection polarizing layer 80 are matched, the joint of the polarizing plates 3 9 becomes more conspicuous Can be eliminated.

[0060] When the polarizing plate 1 is attached to the transparent substrates 34 and 35, the release sheet 24 provided on the small polarizing plate is peeled off, the adhesive layer 24 surface is exposed, and the liquid crystal display panel 31 is transparent. Laminate on the surface of the base materials 34 and 35, and press and stick with a pressure roller. [0061] According to the polarizing plate forming method described above, the joints of the small polarizing plates can be made inconspicuous. However, when viewed microscopically, there is a slight gap in the joint, and there is an air layer in the gap. The reflection of light at the joint 11 will be described with reference to FIG. FIG. 11 is an enlarged cross-sectional view of the joint portion 11. Since the refractive index of the air layer is 1 whereas the refractive index of the polarizing plate is about 1.5, reflection occurs at the interface between the air layer 11a and the polarizing plates (small polarizing plates 2a and 2b). Even if the junction 11 is narrow, the junction 11 can be seen due to the interface reflection. Hereinafter, a method for making the joint portion 11 less noticeable will be described.

[0062] In order to make the joint portion 11 less noticeable, it is preferable to form a transparent resin portion 71 in the joint portion 11 as shown in FIGS. 12 (a) and 12 (b). As the transparent resin used for the transparent resin part 71, epoxy resin, acrylic resin, vinyl resin, polyimide, or the like can be used. A base resin used in a polarizing plate may be used. For example, polyvinyl alcohol or triacetyl cellulose may be used. The refractive index of transparent resin is generally about 1.3 to 1.7, which is close to the refractive index of a polarizing plate. Therefore, since the interface reflection is smaller than that of the air layer, the joint portion becomes inconspicuous. More preferably, a transparent resin having a refractive index equal to that of the polarizing plate is desirable.

An example of a method for providing the transparent resin portion 71 in the joint portion 11 will be described with reference to FIG. As shown in FIG. 12 (a), a transparent resin 70 is applied to the joint 11 using a dispenser 72 with a precision nozzle. After application, allow some time for the oil to penetrate into the joint. The transparent resin may be pushed into the joint portion 11 while removing the excess transparent resin using a squeegee or the like. Thereafter, the transparent rosin is dried. The transparent resin 70 may include a material having an adhesive function, a thermosetting material, or a photocurable material. In this case, after the transparent resin part is formed, an appropriate curing process is performed. However, since the polarizing plate may change in quality, it is not preferable to apply UV light or high temperature, for example, 100 ° C or higher. Visible light curable materials and materials that cure at a temperature that does not damage the polarizing plate can be used. preferable. By doing so, a transparent resin portion 71 can be formed at the joint as shown in FIG. 12 (b). If necessary, a protective layer may be provided to cover the small polarizing plates 2a and 2b and the transparent resin 70.

Note that the method of forming the transparent resin portion 71 in the bonding portion 11 can also be applied when bonding a polarizing plate without using a temporary film. For example, as shown in Figure 13 (a) Even if the transparent resin portion 71 is formed between the small polarizing plates 2a and 2b, the joint portion 11 can be made inconspicuous to some extent. Further, as shown in FIG. 13 (b), after the small polarizing plates 2a and 2b are formed on the liquid crystal panel, the transparent resin portion 71 may be formed on the joint portion 11. The transparent resin may also serve as an adhesive.

[0065] As shown in FIG. 13 (b), when a large polarizing plate in which a small polarizing plate is connected to only one surface of a liquid crystal display panel is laminated and used, one sheet without a joint portion is used. It is better to place the polarizing plate on the surface of the liquid crystal display panel (light emitting surface from the backlight) and the polarizing plate with the joint on the back surface of the liquid crystal display panel (light incident surface from the backlight). . By doing so, when the user observes the screen of the liquid crystal display device, the bonded portion of the polarizing plate is hardly visible.

[0066] Generally, a polarizing plate is produced by cutting a polarizing film raw material into a predetermined size. In many cases, the longitudinal direction of the polarizing film raw material is the same as the polarization axis direction. Therefore, as described above, in order to arrange a single polarizing plate without a joint on the surface of the liquid crystal display panel (light emission surface of the backlight power), the polarization axis direction of the polarizing plate on the front side is displayed on the liquid crystal display. It should be the same direction as the long side of the panel.

[0067] When the transparent resin portion 71 is formed, a selective reflection polarizing layer 80 may be disposed between the polarizing plate 39 on the incident light side and the backlight 32 as shown in FIG. As the selective reflection polarizing layer 80, for example, a brightness enhancement film “DBEF” (manufactured by 3M) can be used. The arrows 81 and 82 and the point 83 shown on the right side of FIG. 14 show an example of the arrangement of the polarization axes of the polarizing plate and the selective reflection polarizing layer. If the polarization axis direction 81 of the polarizing plate 39 on the incident light side formed by joining the small polarizing plates and the polarization axis direction 82 of the selective reflection polarizing layer are combined, in addition to the effect of the transparent resin portion 71, The joint of the polarizing plate 39 can be made even less conspicuous.

[0068] For example, as shown in FIG. 4 and the like, when two small polarizing plates 2a and 2b are joined to form one large polarizing plate 2, in general, two small polarizing plates having the same size are arranged in the center. If the polarizing plates are connected together to form a single polarizing plate, the polarizing plate can be used efficiently. However, if the joint of the polarizing plates exists in the center of the polarizing plate, the joints of the polarizing plates may be noticeable when displaying an image as a liquid crystal display panel. Especially when the display on the screen is black, the joints of the polarizing plates are easily noticeable. As a countermeasure, when joining small polarizing plates, for example, in Fig. 5 (b) and Fig. 5 (c) As shown, it is effective to dispose the small polarizing plate so that the joint (joint portion between the small polarizing plates) avoids the central portion of the polarizing plate.

Specifically, as shown in FIG. 15 (a), in the polarizing plate 1 in which three small polarizing plates 2q, 2r, 2s are joined in the left-right direction, the joint of the small polarizing plates 2q, 2r, 2s Is preferably disposed on both the left and right sides of the center line 12 so as to avoid the central portion C of the polarizing plate 1 (see FIG. 16). Here, the center portion C refers to a range of up to 50% of the length from the center line 12 in the left-right direction to the end portion in the left-right direction.

[0070] FIG. 15 (b) shows an example in which, when two small polarizing plates 2t and 2u are joined in the left-right direction, the joint between the small polarizing plates 2t and 2u is arranged avoiding the central portion C. FIG. Thus, even when two small polarizing plates are joined, it is preferable that the joint between the small polarizing plates is arranged so as to avoid the central portion C.

FIG. 15 (c) shows an example in which three small polarizing plates are joined vertically in the vertical direction. In such a case, it is preferable that the joints of the small polarizing plates 2v, 2w, and 2x are arranged above and below the center line 12a so as to avoid the central portion C of the polarizing plate 1. Here, the central portion C refers to a range of up to 50% of the length from the vertical center line 12a to the end portion.

Further, as shown in FIG. 15 (d), when two small polarizing plates 2y and 2z are joined in the vertical direction, they can be provided so as to avoid the central portion E and the central portion C. . Although not shown, a small polarizing plate joint may be provided above the center line 12a!

[0073] Since the polarizing plate is usually laminated so as to cover the entire screen of the display panel, the central portion C of the polarizing plate refers to the same region as the central portion of the screen of the liquid crystal display panel. . The central part of the display panel screen (that is, the central part C of the polarizing plate) is the 1Z4 area at the center of the entire screen D of the display panel as shown in FIG. In other words, the center line force is 50% of each area excluding the 25% area from the vertical and horizontal edges of the screen D of the display panel. It is preferable that a small polarizing plate is disposed so that the central portion C of this display panel (polarizing plate) is avoided from the joint (junction) between the small polarizing plates.

[0074] In the example shown in Fig. 15, a large polarizing plate is formed using a temporary film, but the polarizing plate is bonded via a transparent resin portion without using a temporary film. In addition, the small polarizing plate can be arranged so as to avoid the central portion of the polarizing plate where the joint of the small polarizing plate is provided. In addition, when the polarizing plate is laminated on the display panel, the small polarizing plate is preferably arranged so that the junction of the small polarizing plate avoids the central portion of the display panel.

[0075] When a small polarizing plate is bonded while avoiding the central portion, the polarization axis of each small polarizing plate may be any of vertical (vertical direction), horizontal (horizontal direction), diagonal direction, etc. . Further, the joints described above are all provided in a straight line parallel to the vertical and horizontal edges of the polarizing plate. The joints may be diagonal straight lines, curved lines, wavy lines, etc. However, if they are formed in such a straight line parallel to the up / down or left / right direction, the length of the joint can be minimized, and machining is easy and machining accuracy is improved. Can be raised. In addition, the position of the joint should be the position of the wiring connected to each TFT of the array substrate of the liquid crystal display panel or the position of the black matrix formed between the color filters of the color filter substrate. The joints are less noticeable.

[0076] As each constituent element of the liquid crystal display element excluding the polarizing plate, each constituent element of a conventional general liquid crystal display element can be used. The liquid crystal display panel of the liquid crystal display element may be a joined panel in which a plurality of liquid crystal display panels are joined together, but it is preferable to use a single large liquid crystal display panel because of excellent display quality. In the above embodiment, the force described in the case where the liquid crystal display panel is a transmission type is applicable to the reflection type liquid crystal panel. In that case, the polarizing plate may be laminated only on one side.

In the above description, the liquid crystal display panel has been described as an example of the display panel. However, the present invention is not limited to the liquid crystal display panel, and the present invention is applied to any display panel including a polarizing plate. be able to. The display panel of the present invention can be suitably used for IJs for large televisions and the like.

Claims

The scope of the claims

[I] A polarizing plate characterized in that a large polarizing plate in which a plurality of small polarizing plates are connected in a plane direction so that their polarization axes are the same is integrally formed on the surface of a temporary film as a support. Board.

[2] The polarizing plate according to [1], wherein the temporary film has the same size as the large polarizing plate.

[3] Temporary film force The polarizing plate according to claim 1, which also has a single film force.

[4] The polarizing plate according to [1], which has a plurality of temporary film forces.

[5] The polarizing plate according to [1], wherein the joining portion between the small polarizing plates is processed to prevent misalignment.

[6] The small polarizing plate is formed of at least a polarizing film, a base film laminated on both sides of the polarizing film, an adhesive layer laminated on one base film side, and a release film. The polarizing plate according to claim 1, wherein:

[7] Base film force The polarizing plate according to claim 6, which is a triacetyl cellulose film.

[8] The polarizing plate according to any one of [1] to [7], wherein a transparent resin portion is formed at a joint portion of the small polarizing plate.

[9] The polarizing plate according to [8], wherein the refractive index of the transparent resin portion is substantially equal to the refractive index of the small polarizing plate.

[10] The polarizing plate according to any one of [1] to [9], wherein the temporary film also serves as a protective layer.

[II] The polarizing plate according to any one of claims 1 to 10, wherein the small polarizing plate is disposed so that a joining portion between the small polarizing plates avoids a central portion of the polarizing plate.

[12] A large polarizing plate is formed by arranging a plurality of small polarizing plates and connecting the small polarizing plates together in a plane direction, and a temporary film as a support is laminated and integrated on the large polarizing plate to form a single sheet. A method for producing a polarizing plate, characterized by comprising a polarizing plate.

[13] The transparent resin portion is formed at the joint portion of the small polarizing plate as described in [12]. Manufacturing method of this polarizing plate.

[14] The method for producing a polarizing plate according to [12], wherein a temporary film provided with an adhesive layer made of a releasable adhesive is used.

[15] The method for producing a polarizing plate according to any one of [12] to [14], wherein the small polarizing plate is disposed so that a joining portion between the small polarizing plates avoids a central portion of the polarizing plate.

[16] A display nonole, characterized in that the polarizing plate according to any one of claims 1 to 11 is laminated!

17. A display element using the display panel according to claim 16.

[18] A large polarizing plate in which a plurality of small polarizing plates are connected in the plane direction so that the polarization axes of the respective small polarizing plates are the same is laminated on the back side of the display panel, 18. The display element according to claim 17, wherein one polarizing plate is laminated.

19. The display element according to claim 18, wherein the polarization axis direction of one polarizing plate laminated on the surface side of the display panel is the same as the long side direction of the display panel.

[20] A display element, wherein a selective reflection polarizing layer is disposed between the polarizing plate on the back side of the display panel according to any one of claims 17 to 19 and the light source.

21. The display element according to claim 20, wherein the polarization axis direction of the selective reflection polarizing layer is the same direction as the polarization axis direction of the panel back-side polarizing plate.

[22] A polarizing plate characterized in that a plurality of small polarizing plates are connected in the plane direction so that the polarization axes thereof are the same, and a transparent resin portion is formed at a joining portion of the small polarizing plates.

23. The polarizing plate according to claim 22, wherein the refractive index of the transparent resin portion is substantially equal to the refractive index of the small polarizing plate.

[24] The polarizing plate according to [22] or [23], wherein the small polarizing plate is disposed so that a joining portion between the small polarizing plates avoids a central portion of the polarizing plate.

[25] A display pane, characterized in that the polarizing plate according to any one of claims 22 to 24 is laminated!

[26] A display element comprising the display panel according to claim 25.

[27] Multiple small polarizing plates on the back side of the display panel have the same polarization axis 27. The display element according to claim 26, wherein a large polarizing plate connected in a plane direction is stacked so that a polarizing plate is stacked on the surface side of the display panel. .

28. The display element according to claim 27, wherein a polarization axis direction of one polarizing plate laminated on the surface side of the display panel is the same as a long side direction of the display panel.

[29] A display element, wherein a selective reflection polarizing layer is disposed between a polarizing plate on the back side of the display panel according to any one of claims 26 to 28 and a light source.

30. The display element according to claim 29, wherein the polarization axis direction of the selective reflection polarizing layer is the same direction as the polarization axis direction of the panel back-side polarizing plate.

[31] A display element in which a plurality of small polarizing plates are connected to each other on the back side of the display panel in a plane direction so that the polarization axes of the respective small polarizing plates are the same, and the polarizing plate on the back side of the display panel And a light source, a selective reflection polarizing layer is disposed.

32. The display element according to claim 31, wherein the polarization axis direction of the selective reflection polarizing layer is the same direction as the polarization axis direction of the panel back-side polarizing plate.

[33] The display element according to [31] or [32], wherein the small polarizing plate is disposed so that a joint portion between the small polarizing plates avoids a central portion of the display panel.

[34] The display element according to any one of [31] to [33], wherein one polarizing plate is laminated on the surface side of the display panel.

[35] The display element according to [34], wherein the polarization axis direction of one polarizing plate laminated on the surface side of the display panel is the same as the long side direction of the display panel.