JP2016090691A - Manufacturing method of polarizing plate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method capable of manufacturing a polarizing plate having an absorption axis precisely directed in a predetermined direction, and a manufacturing method of a liquid crystal panel.SOLUTION: The present manufacturing method of a polarizing plate is a method of manufacturing a polarizing plate having an absorption axis directed in a predetermined direction, and includes an original plate absorption axis detection step S14 of detecting a direction of an absorption axis in the original plate of a polarizing plate, and a processing step S16 of processing the original plate of a polarizing plate to obtain a polarizing plate, where in the processing step S16, the original plate of a polarizing plate is processed so that the direction of the absorption axis detected in the original plate absorption axis detection step S14 is directed in a predetermined direction in a polarizing plate to be obtained.SELECTED DRAWING: Figure 4

Description

  The present invention relates to a method for manufacturing a polarizing plate, and also relates to a method for manufacturing a liquid crystal panel.

  As a polarizing plate, a linear polarizing plate is known. The linearly polarizing plate has an absorption axis and a transmission axis perpendicular to the absorption axis, absorbs light oscillating in the absorption axis direction, and transmits light oscillating in the transmission axis direction. Such a polarizing plate is manufactured, for example, by cutting a strip-shaped polarizing plate into a predetermined size (see Patent Documents 1 and 2). Here, the band-shaped polarizing plate is manufactured by, for example, laminating protective films on both sides or one side of a band-shaped polarizer film. A strip-shaped polarizer film is usually produced by uniaxially stretching a strip-shaped raw material film in the longitudinal direction. In such a manufacturing method, the direction of the absorption axis of the band-shaped polarizing plate is parallel to the direction in which the raw material film is stretched in uniaxial stretching. And since uniaxial stretching of a raw material film is performed in a longitudinal direction, it is assumed that the longitudinal direction of a strip | belt-shaped polarizing plate corresponds with an absorption-axis direction. Therefore, a polarizing plate is manufactured from the strip-shaped polarizing plate so that the absorption axis of the polarizing plate faces a predetermined direction in the polarizing plate with respect to the longitudinal direction of the strip-shaped polarizing plate. Conventionally, the polarizing plate manufactured in this way has endured practical use even when applied to, for example, a liquid crystal display device.

JP-A-11-231129 Japanese Patent Laid-Open No. 11-2724

  When a polarizing plate is manufactured assuming that the longitudinal direction of the strip-shaped polarizing plate is the direction of the absorption axis, actually, the predetermined direction of the absorption axis required for the polarizing plate as a product and the actual absorption axis of the polarizing plate It has been found that there is a case where a slight deviation (for example, about 0.2 ° to 0.3 °) may occur between the first and second directions. Such a shift is a shift that occurs between the stretching direction when the raw material film is uniaxially stretched in the production of a strip-shaped polarizing plate to be a polarizing plate and the longitudinal direction of the strip-shaped polarizing plate, and the polarizing plate from the strip-shaped polarizing plate. This may be due to errors in cutting. On the other hand, in recent years, for example, higher contrast is demanded in displays for small and medium-sized portable devices. When contrast increases in a display or the like, if there is a slight shift between the specified absorption axis direction required for the product polarizing plate and the actual absorption axis direction of the polarizing plate, this is caused by the shift. There is a risk that the image quality will deteriorate.

  Therefore, the present invention provides a method capable of producing a polarizing plate in which the direction of the absorption axis is accurately oriented in a predetermined direction, and further provides a method for producing a liquid crystal panel.

  A method of manufacturing a polarizing plate according to one aspect of the present invention is a method of manufacturing a polarizing plate in which the direction of the absorption axis is in a predetermined direction, and detects the direction of the absorption axis in the original plate of the polarizing plate. And a processing step of obtaining a polarizing plate by processing the polarizing plate original plate. In the processing step, the direction of the absorption axis of the polarizing plate original plate detected in the original plate absorption axis detection step is a polarizing plate to be obtained. The polarizing plate original plate is processed so as to face the predetermined direction.

  In this method, the absorption axis of the polarizing plate original plate is detected. And a polarizing plate is manufactured based on the detection result of an absorption axis. Thus, since the detection result of the absorption axis is used, it is possible to manufacture a polarizing plate in which the direction of the absorption axis is accurately oriented in a predetermined direction.

  In one embodiment, in the processing step, the end surface of the polarizing plate original plate is cut so that the direction of the absorption axis of the polarizing plate original plate detected in the original plate absorption axis detection step faces a predetermined direction in the polarizing plate to be obtained. May be.

  In the embodiment in which the end face of the polarizing plate original plate is cut, a method of manufacturing the polarizing plate includes a single wafer cutting step of cutting out a single wafer polarizing plate from a strip-like polarizing plate, and a polarizing plate that is a polarizing plate original plate from the single wafer polarizing plate. You may further provide the intermediate body cutting process which cuts out an intermediate body.

  In this case, the polarizing plate intermediate as the polarizing plate original plate is cut out from the single-wafer polarizing plate cut out from the strip-shaped polarizing plate. Due to the influence of the cutting error or the like generated in each cutting step, the direction of the absorption axis of the polarizing plate intermediate that is the polarizing plate original plate may deviate from the absorption axis direction assumed in advance in the band-shaped polarizing plate. Even in such a case, in the manufacturing method described above, the direction of the absorption axis of the polarizing field intermediate that is the polarizing plate original plate is detected, and the polarizing plate is obtained based on the detection result. Therefore, it is possible to more reliably obtain a polarizing plate in which the direction of the absorption axis is accurately oriented in a predetermined direction.

  In one embodiment, in the processing step, the polarizing plate original plate may be cut and processed so that the direction of the absorption axis of the polarizing plate original plate detected in the original plate absorption axis detection step faces a predetermined direction in the polarizing plate to be obtained. Good.

  In one embodiment, the processing steps include an intermediate cutting step for cutting out a polarizing plate intermediate from a polarizing plate original plate, an intermediate absorption axis detecting step for detecting the direction of the absorption axis of the polarizing plate intermediate, and a polarizing plate intermediate Cutting the end face of the substrate, and in the intermediate cutting step, the direction of the absorption axis of the polarizing plate original plate detected in the original plate absorption axis detection step is the same in the polarizing plate intermediate to be obtained In addition, in the step of cutting the polarizing plate original plate and cutting the end face of the polarizing plate intermediate, the direction of the absorption axis of the polarizing plate intermediate detected in the intermediate absorption axis detection step is in the polarizing plate to be obtained. You may cut the end surface of a polarizing plate original plate so that it may face the predetermined direction.

  In this case, the polarizing plate intermediate is cut from the polarizing plate original plate by cutting the polarizing plate original plate so that the direction of the absorption axis of the polarizing plate original plate detected in the original plate absorption axis detecting step is the same in the polarizing plate intermediate. Cut out. Therefore, a polarizing plate intermediate in which the absorption axis directions are aligned is obtained. And the absorption axis of a polarizing plate intermediate body is further detected, and the polarizing plate is obtained based on the detection result. Since the polarizing plate is obtained based on the detection result in the absorption axis direction of the polarizing plate intermediate, it is easy to produce a polarizing plate in which the absorption axis direction is in a predetermined direction. Furthermore, since the polarizing plate is obtained from the polarizing plate intermediate based on the detection result in the direction of the absorption axis of the polarizing plate intermediate, it is possible to reduce the influence of errors when the polarizing plate intermediate is cut out from the polarizing plate original plate. As a result, it is easier to produce a polarizing plate whose absorption axis direction is in a predetermined direction.

  In the form of obtaining the polarizing plate intermediate or the polarizing plate from the polarizing plate original plate, it may further comprise a single wafer cutting step of cutting out the single-wafer polarizing plate as the polarizing plate original plate from the strip-shaped polarizing plate.

  A single-wafer polarizing plate as a polarizing plate original plate is cut out from a strip-shaped polarizing plate. In this case, the direction of the absorption axis of the single-wafer polarizing plate that is the polarizing plate original plate may deviate from the absorption axis that is assumed in advance with respect to the strip-shaped polarizing plate due to the influence of a cutting error or the like generated in the cutting step. . Moreover, the direction of the absorption axis assumed in the strip-shaped polarizing plate may not be aligned. Even in such a case, in the above manufacturing method, the direction of the absorption axis of the single-wafer polarizing plate that is the polarizing plate original plate is detected, and the polarizing plate is obtained based on the detection result. Therefore, it is possible to more reliably obtain a polarizing plate in which the direction of the absorption axis is in a predetermined direction.

  In one embodiment, the polarizing plate original plate is a strip-shaped polarizing plate, and in the processing step, the polarizing plate original plate is cut so that the absorption axis direction of the polarizing plate original plate detected in the original plate absorption axis detection step is directed to a predetermined direction. It may be processed.

  The direction of the absorption axis assumed in the band-shaped polarizing plate may not be aligned. Even in such a case, in the manufacturing method described above, the direction of the absorption axis of the strip-shaped polarizing plate that is the polarizing plate original plate is detected, and the polarizing plate is obtained based on the detection result. Therefore, it is possible to more reliably obtain a polarizing plate in which the direction of the absorption axis is accurately oriented in a predetermined direction.

  In the form in which the polarizing plate original plate is a band-shaped polarizing plate, the processing steps in the method for manufacturing a polarizing plate include an intermediate cutting step of cutting out the polarizing plate intermediate from the polarizing plate original plate, and detecting the direction of the absorption axis of the polarizing plate intermediate The intermediate absorption axis detecting step and the step of cutting the end face of the polarizing plate intermediate, and in the intermediate cutting step, the direction of the absorption axis of the polarizing plate original plate detected in the original plate absorption axis detecting step In the step of cutting the polarizing plate original plate and cutting the end face of the polarizing plate intermediate so as to be the same in the polarizing plate intermediate to be obtained, the polarizing plate intermediate detected in the intermediate absorption axis detection step The end face of the polarizing plate original plate may be cut so that the direction of the absorption axis is directed to a predetermined direction in the polarizing plate to be obtained.

  The absorption axis of the strip-shaped polarizing plate is detected, and the polarizing plate intermediate is cut out from the strip-shaped polarizing plate based on the detection result. Therefore, even if the direction of the absorption axis assumed in the band-shaped polarizing plate is not uniform, it is possible to obtain a polarizing plate intermediate in which the direction of the absorption axis faces the same direction in the polarizing plate intermediate. Furthermore, since the polarizing plate is obtained based on the detection result obtained by detecting the absorption axis of the polarizing plate intermediate, it is possible to reduce the influence of errors when cutting out the polarizing plate intermediate. As a result, it is easier to manufacture a polarizing plate in which the direction of the absorption axis is accurately oriented in a predetermined direction.

  The band-shaped polarizing plate may include a uniaxially stretched polarizing layer.

  When the polarizing layer is uniaxially stretched, the direction of the absorption axis can be assumed as the stretching direction. However, due to the influence of bowing during uniaxial stretching, the band-shaped polarizing plate tends to have a case where the directions of the absorption axes are not aligned. Therefore, in the form in which the strip-shaped polarizing plate includes a uniaxially stretched polarizing layer, the polarizing plate in which the direction of the absorption axis is accurately oriented in the predetermined direction is obtained by the above manufacturing method including the step of detecting the direction of the absorption axis. It is possible to obtain more reliably.

  The strip-shaped polarizing plate may have a width of 1000 mm or more. In this case, the above-described bowing effect is likely to occur. For this reason, the above manufacturing method including the step of detecting the direction of the absorption axis is effective for obtaining a polarizing plate in which the direction of the absorption axis is accurately oriented in a predetermined direction.

  In one embodiment, the planar view shape of the polarizing plate is rectangular or square, and the length of the diagonal line of the polarizing plate may be 350 mm or less, and is usually 12.5 mm or more, preferably 50 mm or more.

  Such polarizing plates tend to be used for small and medium-sized displays for which high contrast has been required. Therefore, the production method described above that can obtain a polarizing plate in which the direction of the absorption axis is accurately oriented in a predetermined direction is effective.

  The polarizing plate may be a polarizing plate for a VA type or IPS type liquid crystal panel.

  The VA type or IPS type liquid crystal display device can display an image with high contrast. For this reason, there is a tendency that image display with higher contrast is required. Therefore, the production method described above that can obtain a polarizing plate in which the direction of the absorption axis is accurately oriented in a predetermined direction is effective.

  The manufacturing method of the liquid crystal panel which concerns on the other side surface of this invention manufactures a polarizing plate with the manufacturing method of the polarizing plate which concerns on one side surface of this invention, and pastes the obtained polarizing plate to a liquid crystal cell, and is liquid crystal. Manufacture panels.

  The polarizing plate bonded to the liquid crystal cell by the method for producing a liquid crystal panel is produced by the method for producing a polarizing plate according to one aspect of the present invention. Therefore, in the manufactured polarizing plate, the absorption axis is accurately oriented in a predetermined direction. Therefore, when an image is displayed on the liquid crystal panel, the image quality can be improved.

  ADVANTAGE OF THE INVENTION According to this invention, the method which can manufacture the polarizing plate whose direction of an absorption axis is exactly a predetermined direction can be provided.

FIG. 1 is a plan view of a polarizing plate manufactured by a manufacturing method of a polarizing plate according to an embodiment. FIG. 2 is a schematic diagram of a strip-shaped polarizing plate for producing the polarizing plate shown in FIG. 3 is a cross-sectional view taken along line III-III in FIG. FIG. 4 is a flowchart of a method for manufacturing a polarizing plate according to one embodiment. Fig.5 (a) is a schematic diagram for demonstrating the process of cutting out a sheet-like polarizing plate from a strip | belt-shaped polarizing plate. FIG. 5B is a plan view of the strip-shaped polarizing plate for schematically showing the cutting position of the strip-shaped polarizing plate. Fig.6 (a) is a schematic diagram for demonstrating the process of cutting out a polarizing plate intermediate body from a single-wafer polarizing plate. FIG.6 (b) is a top view which shows typically the cutting position of the polarizing plate intermediate body in a single-wafer polarizing plate. FIG. 7 is a drawing schematically showing an absorption axis detection step. FIG. 8 is a drawing showing a shaved region of the polarizing plate from the polarizing plate intermediate based on the detection result of the absorption axis. FIG. 9 is a schematic diagram showing an end face processing step. FIG. 10 is a flowchart showing a method for manufacturing a polarizing plate according to another embodiment. FIG. 11 is a drawing for explaining a cutting process of a single-wafer polarizing plate. FIG. 12 is a flowchart showing a method for manufacturing a polarizing plate according to still another embodiment. FIG. 13 is a diagram for explaining a case where a single-wafer polarizing plate is cut out from a strip-shaped polarizing plate based on the detection result of the absorption axis. FIG. 14 is a drawing schematically showing a configuration of a liquid crystal panel manufactured by a method for manufacturing a liquid crystal panel according to an embodiment.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. The same symbols are assigned to the same elements. A duplicate description is omitted. The dimensional ratios in the drawings do not necessarily match those described. In the description, words indicating directions such as “up” and “down” are convenient words based on the state shown in the drawings.

(First embodiment)
FIG. 1 is a plan view of a polarizing plate manufactured by a manufacturing method of a polarizing plate according to an embodiment. Polarizer 10 has an absorption axis _{S A,} and a transmission shaft _{S T} perpendicular to the absorption axis (polarization axis) _{S A.} The polarizing plate 10 is an optical element having a polarization characteristic that absorbs light oscillating in the absorption axis S _A direction and selectively transmits light oscillating in the transmission axis S _T direction.

The polarizing plate 10 is applied to a liquid crystal display device. For example, the polarizing plate 10 can be bonded to both surfaces of the liquid crystal cell to constitute a part of the liquid crystal panel. An example of the planar view shape (shape seen from the thickness direction) of the polarizing plate 10 is a rectangle such as a rectangle or a square as shown in FIG. Absorption axis S _A direction of the polarizing plate 10 is oriented in a predetermined direction in the polarizer 10.

  The predetermined direction is a direction at a predetermined angle θ with respect to one side of the polarizing plate 10 as a reference. For example, when the planar view shape of the polarizing plate 10 is a rectangle, the predetermined direction is a direction with a predetermined angle θ = 0 (that is, a direction parallel to the long side) and a predetermined angle θ = 45 ° with respect to the long side. Examples of the direction may be exemplified. For simplification of description, unless otherwise specified, a configuration of the polarizing plate 10 in which the shape in plan view is a rectangle and the predetermined direction is the long side direction will be described below.

  The magnitude | size of the polarizing plate 10 should just be set according to the device in which the polarizing plate 10 is used. An example of the size of the polarizing plate 10 is a polarizing plate in which the length of the diagonal line is 50 mm to 350 mm, that is, a length corresponding to a so-called 2 type to 12 type. When the polarizing plate 10 is applied to a liquid crystal display device, the liquid crystal panel to which the polarizing plate 10 is bonded is not particularly limited. For example, a VA (Vertical Alignment) type that can display an image with high contrast, and IPS ( An in-place-switching type liquid crystal panel is exemplified.

  The polarizing plate 10 is manufactured from the strip-shaped polarizing plate 12 shown in FIG. FIG. 2 is a schematic diagram of a strip-shaped polarizing plate for producing the polarizing plate shown in FIG.

  The example of the length of the longitudinal direction of the strip | belt-shaped polarizing plate 12 is 1000m-2000m. The strip-shaped polarizing plate 12 is wound in a roll shape. A roll around which the strip-shaped polarizing plate 12 is wound is referred to as an original fabric roll 14. The example of the width | variety of the strip | belt-shaped polarizing plate 12 is 1000 mm or more.

  3 is a cross-sectional view taken along line III-III in FIG. The strip-shaped polarizing plate 12 is a laminate having a polarizer film 12a as a polarizing layer that selectively transmits light that vibrates in one direction. An example of the polarizer film 12 a is a film in which a dichroic dye is adsorbed and oriented on a PVA film uniaxially stretched in the longitudinal direction of the strip-shaped polarizing plate 12. The dichroic dye is oriented in the stretching direction of the PVA film and adsorbed on the PVA film. Thereby, the polarizer film 12a transmits the light orthogonal to the orientation direction of the dichroic dye (that is, the molecular major axis direction) and absorbs the light in the direction orthogonal thereto, that is, the polarization property. Have. Examples of dichroic dyes are iodine and dichroic organic dyes. An example of the thickness of the polarizer film 12a is 1 μm to 30 μm.

  Protective films 12b and 12c as protective layers for protecting the polarizer film 12a are bonded to both surfaces of the polarizer film 12a. An example of the protective films 12b and 12c is a cellulose film, and an example of the cellulose film is a TAC (triacetyl cellulose) film. The example of the thickness of the protective films 12b and 12c is 10 micrometers-200 micrometers.

  In the above description, the band-shaped polarizing plate 12 having a structure in which the polarizer film 12a is sandwiched between the protective films 12b and 12c has been described. However, the band-shaped polarizing plate 12 has the protective film 12b laminated on one side of the polarizer film 12a and the other side. The surface may have a structure in which a protective film is not laminated.

  A surface protective film (or a protective film) 12d for protecting the protective film 12b may be bonded to the protective film 12b. An example of the thickness of the surface protective film 12d is 30 μm to 100 μm. Examples of the material of the surface protective film 12d are polyethylene, polypropylene, and polyester.

  Furthermore, an adhesive layer 12e for bonding the polarizing plate 10 as a product to another member such as a liquid crystal cell may be formed on the protective film 12c. An example of the thickness of the pressure-sensitive adhesive layer 12e is 5 μm to 30 μm. The example of the adhesive which comprises the adhesive layer 12e contains an acrylic adhesive, a urethane adhesive, and a silicone adhesive. In the form in which the pressure-sensitive adhesive layer 12e is formed, a separate film 12f may be detachably bonded onto the pressure-sensitive adhesive layer 12e. The separate film 12f is a film for preventing other regions, dust, and the like from adhering to the pressure-sensitive adhesive layer 12e until the polarizing plate 10 as a product is used. An example of the thickness of the separate film 12f is 30 μm to 100 μm.

  The strip-shaped polarizing plate 12 is manufactured as follows, for example. That is, the strip-shaped raw material film is uniaxially stretched in the longitudinal direction. An example of the raw material film is a non-stretched PVA film having no orientation. The example of a draw ratio is 4 times-5 times. The uniaxial stretching method may be either a dry uniaxial stretching method or a wet uniaxial stretching method. Uniaxial stretching can be realized, for example, by stretching the raw material film while applying a tension in the longitudinal direction while contacting the hot roll. After uniaxially stretching the raw material film, the dichroic dye is adsorbed and oriented on the PVA film by immersing the PVA film, which is the uniaxially stretched raw material film, in an aqueous solution containing a dichroic dye in the stretching direction. Film 12a is obtained. And the said basic structure is obtained by bonding the protective films 12b and 12c to both surfaces of the polarizer film 12a, respectively. Then, the strip | belt-shaped polarizing plate 12 is obtained by providing the surface protective film 12d, the adhesive layer 12e, and the separate film 12f suitably.

  In the example of the manufacturing method of the strip-shaped polarizing plate 12, the dichroic dye is adsorbed and oriented on the PVA film after uniaxially stretching the raw material film. However, the raw material film may be uniaxially stretched during or after the dichroic dye is adsorbed and oriented.

A polarizer film 12 a (more specifically, a PVA film) included in the strip-shaped polarizing plate 12 is uniaxially stretched in the longitudinal direction of the strip-shaped polarizing plate 12. Therefore, the band-shaped polarizing plate 12, the absorption axis S _A direction, substantially coincides with the longitudinal direction of the strip polarizer 12. However, when uniaxially stretched, bowing may occur in which the edge portion is slightly curved inward in the width direction. Therefore, as shown in FIG. 2, there may be cases where the location of the strip polarizing plate 12, the absorption axis S _A direction is deviated from the longitudinal direction. Deviation angle from the longitudinal direction of the absorption axis _{S A} direction is, for example, approximately 0.2 ° to 0.3 °. In FIG. 2, this misalignment angle is exaggerated.

  Next, a method for producing the polarizing plate 10 shown in FIG. 1 from the strip-like polarizing plate 12 shown in FIG. 2 will be specifically described.

FIG. 4 is a flowchart of a method for manufacturing a polarizing plate according to one embodiment. When manufacturing the polarizing plate 10, first, the single-wafer polarizing plate (1st polarizing plate intermediate body) 16 is cut out from the strip | belt-shaped polarizing plate 12 (single-sheet cutting process S10). Next, a polarizing plate intermediate body (second polarizing plate intermediate body) 22 is cut out from the single-wafer polarizing plate 16 (intermediate body cutting step S12). Subsequently, detecting the absorption axis S _A of the polarizing plate Intermediate 22 cut out (absorption axis detection step S14). Then, the polarizing plate 10 is obtained by cutting (end surface processing) the end surface of the polarizing plate intermediate body 22 (end surface processing process S16). Hereinafter, each step will be described.

(1) Single wafer cutting step S10
The single wafer cutting step S10 will be described with reference to FIGS. 5 (a) and 5 (b). Fig.5 (a) is a schematic diagram for demonstrating the process of cutting out a sheet-like polarizing plate from a strip | belt-shaped polarizing plate. FIG. 5B is a plan view of the strip-shaped polarizing plate for schematically showing the cutting position of the strip-shaped polarizing plate.

  In the single wafer cutting step S <b> 10, the strip-shaped polarizing plate 12 is unwound from the raw roll 14. Then, the fed strip-shaped polarizing plate 12 is carried into a cutting device 18 disposed on the feeding direction (or transport direction) of the strip-shaped polarizing plate 12. The cutting device 18 cuts the strip-shaped polarizing plate 12 with a predetermined length by the cutting blade 18 a, and cuts the single-wafer polarizing plate 16 from the strip-shaped polarizing plate 12. The cutting position of the strip-shaped polarizing plate 12 may be set at a constant interval in the longitudinal direction, for example, like a virtual cutting line indicated by a two-dot chain line in FIG. The position of the virtual cutting line may be input to the cutting device 18 in advance. In the cutting device 18, the strip-shaped polarizing plate 12 may be cut by a laser beam instead of the cutting blade 18a.

(2) Intermediate cutting step S12
The intermediate cutting step S12 will be described with reference to FIGS. 6 (a) and 6 (b). Fig.6 (a) is a schematic diagram for demonstrating the process of cutting out a polarizing plate intermediate body from a single-wafer polarizing plate. FIG.6 (b) is a top view which shows typically the cutting position of the polarizing plate intermediate body in a single-wafer polarizing plate.

In the intermediate body cutting step S12, the single-wafer polarizing plate 16 is carried into the cutting device 20 arranged in the conveying direction. The cutting device 20 cuts out a plurality of polarizing plate intermediate bodies 22 from the single-wafer polarizing plate 16 by the cutting blade 20a. The polarizing plate intermediate 22 is a polarizing plate intermediate having a size in which a shaving (for example, a width of 0.5 mm) is provided with respect to the shape of the manufactured polarizing plate 10. In the present embodiment, the polarizing plate intermediate 22 corresponds to a polarizing plate original plate. The cutting position of the single-wafer polarizing plate 16 may be set with a virtual cutting line for the polarizing plate intermediate 22 shown by a two-dot chain line in FIG. Cutting line for polarizer Intermediate 22, the conveying direction of the absorption axis S _A is sheet polarizer 16 (i.e., the longitudinal direction of the strip-like polarizing plate 12) can be set on the assumption that along. A cutting line (cutting position) for the polarizing plate intermediate 22 may be input to the cutting device 20 in advance. The cutting blade 20a of the cutting device 20 should just be attached to the cutting device 20 so that the direction of the cutting blade 20a can be changed so that it can cut | disconnect along a cutting line. In the cutting device 20, the single-wafer polarizing plate 16 may be cut by a laser beam instead of the cutting blade 20a.

(3) Absorption axis detection step S14
The absorption axis detection step S14 will be described with reference to FIG. FIG. 7 is a drawing schematically showing a detection process in the absorption axis direction. Absorption axis S _A can be detected by the rotating analyzer method.

Specifically, in the thickness direction of the polarizing plate intermediate body 22, light is transmitted from the light source 24 arranged on one side of the polarizing plate intermediate body 22 (below the polarizing plate intermediate body 22 in FIG. 7). Irradiate the body 22. Irradiation light is usually unpolarized light in a non-polarized state. For example, light emitted from a normal light source such as an incandescent bulb, a fluorescent lamp, or an LED is usually unpolarized light. The light that has passed through the polarizing plate intermediate 22 is arranged on the other side of the polarizing plate intermediate 22 in the thickness direction of the polarizing plate intermediate 22 (above the polarizing plate intermediate 22 in FIG. 7). Detection is performed by the detector 26. Between the polarizing plate intermediate body 22 and the photodetector 26, a linear polarizing plate 28, which is an analyzer having a known absorption axis S _A direction and transmission axis _ST direction, is connected to the optical axis of the light output from the light source 24. And the linearly polarizing plate 28 are arranged so as to be rotatable about the intersection. What is necessary is just to control the rotation amount of the linearly polarizing plate 28 with the control apparatus which is a computer, for example. Moreover, what is necessary is just to process the signal from the photodetector 26 with the said control apparatus.

When detecting the absorption axis S _A of the polarizing plate Intermediate 22 outputs the light from the light source 24. When the light output from the light source 24 is incident on the polarizer Intermediate 22, light vibrating in the transmission axis S _T direction of the polarizer Intermediate 22 selectively pass through the polarizing plate Intermediate 22. Therefore, the linear polarizer 28, to rotate the optical axis of the light output from the light source 24 as the center axis, and the absorption axis S _A direction of the absorption axis S _A direction and the polarizer Intermediate 22 linear polarizer 28 When the state is orthogonal, that is, in the crossed Nicol state, the amount of light incident on the photodetector 26 is minimized. Therefore, when the amount of light incident on the photodetector 26 is minimized, the absorption axis S _A direction of the linearly polarizing plate 28 is the absorption axis S _A direction of the polarizing plate Intermediate 22.

Detection of the absorption axis S _A direction may be performed in the polarizing plate Intermediate 22 at a plurality of positions. Detection Points of absorption axis S _A direction is, for example, may set the width direction of the polarizer Intermediate 22.

  The detection device in the absorption axis direction including the light source 24, the linearly polarizing plate 28, and the photodetector 26 may be disposed on the transport line of the polarizing plate intermediate body 22 cut out from the single-wafer polarizing plate 16, for example. Moreover, it may be installed in a place different from the transfer line.

Light source 24, the linear polarizer 28 and photodetector 26 is not particularly limited as long as it is used in the detection of the absorption axis S _A. The arrangement relationship among the light source 24, the linearly polarizing plate 28 and the photodetector 26 is not particularly limited as long as the crossed Nicols state can be realized by the polarizing plate intermediate body 22 and the linearly polarizing plate 28. For example, the linearly polarizing plate 28 may be disposed between the light source 24 and the polarizing plate intermediate body 22. Further, linearly polarizing plates 28 may be disposed above and below the polarizing plate intermediate body 22. In this case, the two linear polarizing plates 28 may be arranged in a parallel Nicol state and rotated in synchronization.

Examples of the absorption axis S _A direction of the detection method a feasible apparatus shown in FIG. 7, Oji Scientific Instruments Co., Ltd. KOBRA, Otsuka RETS-100 and RE-100P, etc. Electronics Co., Ltd. and the like.

Detected absorption axis S _A direction it suffices recorded. This recording may, for example, it is sufficient to mark the absorption axis S _A direction abrasion is region like when the polarizer Intermediate 22 cut out a polarizing plate 10.

(4) End face processing step S16
In the end surface processing step S16, based on the absorption axis _{S A} direction of the detection result, the end surface 22a of the polarization plate Intermediate 22, 22b, 22c, by cutting a 22 d, to obtain a polarizing plate 10. The cutting includes polishing of the end faces 22a, 22b, 22c, and 22d. The end face processing step S16 will be described with reference to FIGS.

FIG. 8 is a drawing showing a shaved region of the polarizing plate from the polarizing plate intermediate based on the detection result of the absorption axis. In FIG. 8, the broken line indicates the absorption axis S _A0 direction when the longitudinal direction of the strip-shaped polarizing plate 12 is assumed to be the absorption axis direction, and the two-dot chain line is based on the detected direction of the absorption axis S _A. The polarizing plate region A is shown. The polarizing plate region A is a portion of the polarizing plate 10 to be cut out by cutting the end faces 22a to 22d in the polarizing plate intermediate body 22. The polarizing plate region A is set so that the absorption axis S _A faces a predetermined direction (longitudinal direction in the present embodiment) in the polarizing plate 10.

FIG. 9 is a schematic diagram showing an end face processing step. As shown in FIG. 9, together end face machining of a plurality of polarizers Intermediate 22 using an absorption axis S stacked body 30 in which the direction is laminated polarizing plate intermediate 22 of a plurality of detected of the _A Do.

  The end face processing step S16 is performed using the end face processing apparatus 32 shown in FIG. The end surface processing device 32 includes a pair of holding members 34A and 34B that hold the stacked body 30 with the stacked body 30 sandwiched from the stacking direction. One holding member 34 </ b> B of the pair of holding members 34 </ b> A and 34 </ b> B is placed on the rotary table 36. A pressing member 38 that presses the holding member 34A toward the holding member 34B is attached to the other holding member 34A. The rotary table 36 and the pressing member 38 are attached to a support base (not shown) so as to be movable in one direction. The pressing member 38 is attached to the support base so that it can rotate in the same direction as the rotary table 36 in synchronization with the rotation of the rotary table 36.

  The end surface processing device 32 has a pair of cutting members 40 </ b> A and 40 </ b> B on the moving direction of the rotary table 36. The pair of cutting members 40 </ b> A and 40 </ b> B are disposed to face each other in the direction orthogonal to the stacking direction of the polarizing plate intermediate body 22 and the moving direction of the rotary table 36 in the stacked body 30. The pair of cutting members 40A and 40B have rotating members 42A and 42B that can rotate about the arrangement direction of the cutting members 40A and 40B as a rotation axis, and face the inner surfaces of the rotating members 42A and 42B (opposing the stacked body 30). A cutting blade 44 is attached to the surface to be cut.

  An example of the end face processing step S16 of the polarizing plate intermediate 22 performed using the end face processing apparatus 32 having the above configuration will be described.

_A laminated body 30 is configured by laminating a plurality of polarizing plate intermediate bodies 22 in which the absorption axis SA is detected. Direction of absorption axis S _A of the polarizing plate Intermediate 22 constituting the layered body 30 are the same. In the laminate 30, the plurality of polarizing plate intermediate bodies 22 are laminated so that the polarizing plate regions 40 shown in FIG. 8 overlap in the laminating direction. The prepared laminate 30 is sandwiched between a pair of holding members 34A and 34B and pressed in the stacking direction by a pressing member 38 to hold the laminate 30 by the holding members 34A and 34B. Thereafter, the rotary table 36 is moved in the moving direction, and the laminate 30 is fed between the pair of cutting members 40A and 40B. At this time, the rotating members 42A and 42B of the cutting members 40A and 40B are rotated. Thereby, a pair of end surfaces (end surface 22c, 22d in the example of FIG. 9) which oppose cutting member 40A, 40B among four end surface 22a-22d of each polarizing plate intermediate body 22 which comprises the laminated body 30 are cut. Cutting (or polishing) is performed by the members 40A and 40B. Further, the cutting table 44 is brought into contact with the end face facing the cutting members 40A and 40B among the end faces 22a to 22d by the rotary table 36 so as to cut out the polarizing plate region 40 indicated by the two-dot chain line shown in FIG. The angle may be adjusted and the distance between the cutting members 40A and 40B and the end face may be appropriately controlled. If the cutting of the pair of end surfaces located on the opposite sides of the polarizing plate intermediate 22 is completed, the rotary table 36 may be rotated to process the remaining pair of end surfaces.

  As described above, the end face processing apparatus 32 cuts the end faces 22a to 22d of the polarizing plate intermediate body 22 and cuts out the polarizing plate 10 from the polarizing plate intermediate body 22, thereby obtaining the polarizing plate 10 as a product. It is done.

  Since the polarizing plate 10 is manufactured from the strip-shaped polarizing plate 12 as described above, the cross-sectional configuration (or layer configuration) of the polarizing plate 10 is the same as the cross-sectional configuration of the strip-shaped polarizing plate 12 shown in FIG. .

In the above manufacturing method, and detects the direction of the absorption axis S _A in the polarizer Intermediate 22 a polarizing plate source plate before stage of the end face machining. Then, based on the detection result, so as to face the absorption axis S _A direction in a predetermined direction in the polarizer 10, performs a cutting of the end face 22a~22d polarizer Intermediate 22, the polarizing plate from the polarizing plate Intermediate 22 I'm cutting 10 out. Therefore, in a polarizing plate 10, the absorption axis S _A direction, the members polarizing plate 10 is applied (e.g., liquid crystal panel) is oriented in a predetermined direction that is desired in such. In the polarizing plate 10, the absorption axis S _A direction coincides with the predetermined direction with higher accuracy.

The absorption axis S _A of the strip-shaped polarizing plate 12 is parallel to the stretching direction of the polarizer film 12 a and substantially along the longitudinal direction of the strip-shaped polarizing plate 12. Therefore, the longitudinal direction of the strip-shaped polarizer 12 on the assumption that the absorption axis S _A direction is also conceivable to produce a polarizing plate. However, by bowing effect in uniaxial stretching at the time of band polarizer 12 is produced, as illustrated in FIG. 2, the region where the direction is shifted to the absorption axis S _A from the longitudinal direction of the strip-like polarizer 12 is caused There may be. Further, a cutting error may occur during the cutting process in the single wafer cutting step S10 and the intermediate cutting step S12. As a result, as shown in FIG. 8, in the polarizing plate intermediate 22, the virtual absorption axis S _A0 direction when the longitudinal direction of the strip-shaped polarizing plate 12 is assumed to be the absorption axis, and the actual absorption axis S as the detection result. Deviation may occur in the _A direction.

Be such deviation has occurred if, in the above manufacturing method, to detect the absorption axis S _A direction of the polarizing plate Intermediate 22 according to the detection result, the absorption axis S _A direction in a predetermined direction in the polarizer 10 The polarizing plate 10 is shaved from the polarizing plate intermediate 22 so as to face. Therefore, it is possible to the absorption axis S _A direction to obtain a polarizing plate 10 a desired direction more reliably.

VA type capable of image display with high contrast, and the polarizing plate applied to the liquid crystal panel of the IPS type, determined for image display with high contrast, the absorption axis S _A direction in the polarizing plate as a product It is required that the predetermined direction coincides with high accuracy. Therefore, the absorption axis S _A direction is higher above production method can be produced a polarizing plate 10 which matches the predetermined direction in accuracy, VA type, and is effective to produce a polarizing plate for a liquid crystal panel of an IPS type is there. When the liquid crystal panel is a VA type, it may be an ASV (Advanced Super View) type.

Unlike a large TV with a large screen size, a display for a small and medium size portable device of type 12 (diagonal length 350 mm) or less is required to have high contrast because the user tends to view the screen from a short distance. Therefore, the absorption axis S _A direction is higher above manufacturing method capable producing matched polarizing plate 10 to the predetermined direction in accuracy, it is effective to produce a polarizing plate used in the display for small portable devices.

The planar view shape of the polarizing plate 10 is a rectangle or a square, and the length of the diagonal line is 12.5 mm to 350 mm. The size is about 0.5 type to 12 type, and further corresponds to 2 type (diagonal length 50 mm) or more. In the form which is length, the polarizing plate 10 is easy to be used for a display for small and medium-sized portable devices. Therefore, the absorption axis S _A direction, the production method can be produced the matching polarizing plate 10 to the predetermined direction with high accuracy, the length of the diagonal is the plan view shape rectangular or square in 12.5mm~350mm This is effective for a certain polarizing plate.

In the embodiment in which the width of the strip-shaped polarizing plate 12 is 1000 mm or more, the above-described bowing effect tends to increase. Therefore, the above-described manufacturing method comprises the absorption axis _{S A} direction detection step, or width 1000 mm, usually absorption axis _{S A} direction from the strip-shaped polarizer 12 3000 mm from a viewpoint of obtaining a polarizing plate 10 is a predetermined direction It is valid.

(Second Embodiment)
FIG. 10 is a flowchart showing a method for manufacturing a polarizing plate according to another embodiment. In the manufacturing method shown in FIG. 10, first, the single-wafer polarizing plate 16 is cut out from the strip-shaped polarizing plate 12 (single-wafer cutting step S20). Next, to detect the direction of the absorption axis _{S A} in sheet polarizer 16 (absorption axis detection step S22). Subsequently, the polarizing plate intermediate body 22 is cut out from the single-wafer polarizing plate 16 (intermediate body cutting step S24). Thereafter, the absorption axis direction of the polarizing plate intermediate 22 is detected (absorption axis detection step S26). And the polarizing plate 10 is obtained by cutting the end surface of the polarizing plate intermediate body 22 (end surface processing) (end surface processing process S28). Intermediate cutting step S24 and subsequent steps, i.e., the intermediate cutting step S24, the absorption axis detecting step S26 and the end surface processing step S28, based on the absorption axis S _A direction of the detection result, obtaining a polarizing plate 10 Correspond. Hereinafter, each step will be described.

  The single wafer cutting process S20 is the same as the cutting process S10 of the single wafer polarizing plate 16 shown in FIG.

In the absorption axis detecting step S22, it detects the direction of the absorption axis S _A single wafer polarizing plate 16. Detection method is the same as the method of detecting the direction of the absorption axis S _A of the polarizing plate Intermediate 22 described by using FIG. That is, in FIG. 7, instead of the polarizing plate intermediate 22, the single-wafer polarizing plate 16 may be disposed and detected. The detection device in the absorption axis direction including the light source 24, the linearly polarizing plate 28, and the photodetector 26 may be disposed, for example, on the conveying line of the single-wafer polarizing plate 16, or may be different from the conveying line. It may be installed at the place. Detection of the absorption axis S _A direction of sheet polarizer 16 may be performed in the polarizing plate Intermediate 22 at a plurality of positions. Detection Points of absorption axis S _A direction is, for example, may set the width direction of the polarizer Intermediate 22.

In the intermediate body cutting step S <b> 24, similarly to FIG. 6A, the single-wafer polarizing plate 16 is carried into the cutting device 20 while being transported, and a plurality of polarizing plate intermediate bodies 22 are cut out from the single-wafer polarizing plate 16. . At this time, based on the detected absorption axis S _A direction, as the direction of absorption axis S _A is oriented in the same direction in the polarizer Intermediate 22, cutting the polarizing plate Intermediate 22 from sheet polarizer 16 Cut with the blade 20a. This will be specifically described with reference to FIG.

FIG. 11 is a drawing for explaining a cutting process of a single-wafer polarizing plate. FIG. 11 shows a plan view of the single-wafer polarizing plate 16. Further, FIG. 11 shows an example of a detected plurality of absorption axis S _A direction. As shown in FIG. 11, in the central portion in the width direction of the sheet polarizer 16, whereas the direction of the absorption axis S _A is parallel to the longitudinal direction, the width direction near the edge of the sheet polarizer 16 in the absorption axis S _A is inclined relative to the longitudinal direction. In this case, as shown in FIG. 11 by a two-dot chain line, to set the virtual cutting line regions have all the absorption axis S _A direction cutout region of the polarizing plate Intermediate 22. In one embodiment, as shown in FIG. 11, to set the virtual cutting line so as to face the absorption axis S _A to the longitudinal direction of the polarizing plate Intermediate 22. In FIG. 11, in the width direction, virtual cutting lines are set in the respective regions in the vicinity of the center portion and in the vicinity of the edge portions on both sides. Then, the single-wafer polarizing plate 16 is cut with a cutting device along the set cutting line by the cutting blade 20 a, and the polarizing plate intermediate body 22 is cut out from the single-wafer polarizing plate 16. Incidentally, in each of the region set by the virtual cutting line, the direction of the absorption axis S _A need not have exactly aligned, in a range within the allowable range of the predetermined direction in the polarizing plate 10 for the purpose It only has to be present.

  The absorption axis detection step S26 and the end surface machining step S28 are the same as the absorption axis detection step S14 and the end surface machining step S16 shown in FIG.

The above manufacturing method, and detects the direction of the absorption axis S _A single wafer polarizing plate 16 corresponding to the polarization plate source plate in the present embodiment. And based on a detection result, the single-wafer polarizing plate 16 is processed and the polarizing plate 10 is obtained. For this reason, the polarizing plate is corrected by correcting the deviation between the absorption axis S _A0 assumed as the longitudinal direction of the strip-shaped polarizing plate 12 and the detected actual absorption axis S _A direction for the same reason as in the first embodiment. 10 can be manufactured. As a result, it is possible to the absorption axis S _A direction to obtain a polarizing plate 10 is a predetermined direction.

Further, as have all the absorption axis S _A direction in the polarizer Intermediate 22, since the sheet polarizer 16 are cut out polarizing plate Intermediate 22, the polarizer Intermediate 22, for example, the influence of Boeing Has been reduced. Since obtaining a polarizing plate 10 from the polarizer Intermediate 22 you have the absorption axis S _A direction, easy absorption axis S _A direction to produce a polarizing plate 10 which faces the predetermined direction.

Further, by detecting the absorption axis S _A direction of the polarizing plate Intermediate 22 again, based on the detection result, to obtain a polarizing plate 10. Therefore, the influence of the error when cutting out the polarizing plate intermediate 22 can also be reduced. As a result, it is possible to the absorption axis S _A direction to obtain a polarizing plate 10 is a predetermined direction more reliably.

Also in the production method is carried out in the flowchart shown in FIG. 10, as described above, the absorption axis S _A direction can be obtained a polarizing plate 10 is a predetermined direction. Therefore, it is the same as in the case of the first embodiment that the manufacturing method is effective for polarizing plates applied to VA-type and IPS-type liquid crystal panels or small-to-medium-sized displays. The width of the strip-shaped polarizing plate 12 is 1000 mm or more, and the planar view shape of the polarizing plate 10 is rectangular or square, and the diagonal length is 350 mm or less, preferably 12.5 mm or more, more preferably 50 mm or more. It is the same as in the case of the first embodiment that the manufacturing method is effective for a certain form.

Here, although the form provided with intermediate body cutting process S24 was demonstrated, you may cut out the polarizing plate 10 from the single-wafer polarizing plate 16 directly. In this case, the polarizing plate 10 may be cut out from the single-wafer polarizing plate 16 so that the absorption axis S _A direction detected in the single-wafer polarizing plate 16 faces a predetermined direction in the polarizing plate 10. Thus, in the form in which the polarizing plate 10 is obtained directly from the single-wafer polarizing plate 16, the polarizing plate 10 can be manufactured more easily.

In the flowchart shown in FIG. 10, and a absorption axis detecting step S26 of detecting the absorption axis S _A direction of the polarizing plate Intermediate 22. However, the absorption axis detection step S26 may not be provided. Absorption axis S _A direction of the polarizing plate Intermediate 22 are aligned, the direction of the absorption axis S _A in the polarizers intermediate 22 are known by detecting the absorption axis S _A single wafer polarizing plate 16. Therefore, as in the case shown in FIG. 8, by setting the polarizing plate area A based on the direction of the absorption axis S _A in the polarizer Intermediate 22, as in the case of the end surface processing step S16, the end face machining The polarizing plate 10 may be cut out from the polarizing plate intermediate body 22 by the device 32.

In the embodiment without the absorption axis detecting step S26, for example, a polarizing plate Intermediate 22 when regarded as a polarizing plate 10, so that the detected absorption axis S _A direction oriented in a predetermined direction, the sheet polarizer 16 The polarizing plate intermediate 2 may be cut out. In this case, the absorption axis S _A direction in the polarizer Intermediate 22 is oriented in a predetermined direction of the polarizer 10. For this reason, the end faces 22a to 22d of the polarizing plate intermediate 22 need only be cut with a certain width, so that the end face processing is easy.

(Third embodiment)
FIG. 12 is a flowchart showing a method for manufacturing a polarizing plate according to still another embodiment. In the manufacturing method shown in FIG. 12, first, the absorption axis direction of the strip-shaped polarizing plate 12 is detected (absorption axis detection step S30). Next, the polarizing plate intermediate body 22 is cut out from the strip-shaped polarizing plate 12 (intermediate body cutting step S32). The absorption axis direction of the polarizing plate intermediate 22 is detected (absorption axis detection step S34). Then, the polarizing plate 10 is obtained by cutting (end surface processing) the end surface of the polarizing plate intermediate body 22 (end surface processing process S36). Intermediate cutting step S32 and subsequent steps, i.e., the intermediate cutting step S32, the absorption axis detecting step S34 and the end surface processing step S36, based on the absorption axis S _A direction of the detection result, obtaining a polarizing plate 10 Correspond. Hereinafter, each step will be described.

In the absorption axis detecting step S30, after feeding the band-shaped polarizing plate 12 from the sheet roll 14, for detecting the absorption axis S _A direction of a band-shaped polarizing plate 12 of the fed-out area. Detection method is the same as the method of detecting the absorption axis S _A direction of the polarizing plate Intermediate 22 described by using FIG. That is, in FIG. 7, the band-shaped polarizing plate 12 may be arranged and detected instead of the polarizing plate intermediate 22. The detection device in the absorption axis direction including the light source 24, the linearly polarizing plate 28, and the photodetector 26 may be disposed on the transport line of the strip-shaped polarizing plate 12, for example. Detection of the absorption axis S _A direction of a band-shaped polarizing plate 12 may be carried out in strip polarizer 12 at a plurality of locations. Detection Points of absorption axis S _A direction is, for example, may be set for the width direction of the belt-like polarizing plate 12.

In the intermediate body cutting step S <b> 32, the belt-shaped polarizing plate 12 is carried into the cutting device while being transported in the feeding direction, and the polarizing plate intermediate body 22 is cut out from the belt-shaped polarizing plate 12. As a cutting device for cutting out the polarizing plate intermediate 22, the cutting device 20 for cutting out the polarizing plate intermediate 22 illustrated in FIG. 6A can be used. This step S32 is the same as when the single-wafer polarizing plate 16 shown in FIG. That is, set the virtual cutting line so as to face the longitudinal direction of the absorption axis S _A direction of the polarizing plate Intermediate 22. Then, the strip-shaped polarizing plate 12 is cut by a cutting device along the set cutting line, and the polarizing plate intermediate 22 is cut out from the strip-shaped polarizing plate 12.

  The absorption axis detection step S34 and the end surface machining step S36 are the same as the absorption axis detection step S14 and the end surface machining step S16 shown in FIG.

In the above manufacturing method, and detects the direction of the absorption axis S _A of the strip polarizer 12. And based on a detection result, the strip | belt-shaped polarizing plate 12 is processed and the polarizing plate 10 is obtained. Therefore, it is possible to produce a polarizing plate 10 while correcting the deviation from the longitudinal direction of the absorbent axis S _A in strip polarizing plate 12 inside due to bowing of the influence at the time of uniaxial stretching in the band polarizer 12 . As a result, it is possible to the absorption axis S _A direction to obtain a polarizing plate 10 a desired direction.

Further, as have all the absorption axis S _A direction in the polarizer Intermediate 22, the band-shaped polarizing plate 12 are cut out polarizing plate Intermediate 22, the polarizer Intermediate 22, for example, the influence of Boeing Has been reduced. Since obtaining a polarizing plate 10 from the polarizer Intermediate 22 you have the absorption axis S _A direction, easy absorption axis S _A direction to produce a polarizing plate 10 which faces the predetermined direction.

Further, by detecting the absorption axis S _A direction of the polarizing plate Intermediate 22 again, based on the detection result, to obtain a polarizing plate 10. Therefore, the influence of the error when cutting out the polarizing plate intermediate 22 can also be reduced. As a result, it is possible to the absorption axis S _A direction to obtain a polarizing plate 10 is a predetermined direction more reliably.

Also in the production method is carried out in the flowchart shown in FIG. 12, as described above, the absorption axis S _A direction can be obtained a polarizing plate 10 is a predetermined direction. Therefore, it is the same as in the case of the first embodiment that the manufacturing method is effective for a polarizing plate applied to a VA-type or IPS-type liquid crystal panel or a small-to-medium display. The width of the strip-shaped polarizing plate 12 is 1000 mm or more, and the planar view shape of the polarizing plate 10 is rectangular or square, and the length of the diagonal line is 350 mm or less, usually 12.5 mm to 350 mm, preferably 50 mm to It is the same as in the case of the first embodiment that the above manufacturing method is effective for the form of 350 mm.

Here, although the form provided with process S32 which cuts out the polarizing plate intermediate body 22 was demonstrated, you may cut out the polarizing plate 10 directly from the strip | belt-shaped polarizing plate 12. FIG. In this case, the detected absorption axis S _A direction in strip polarizer 12 may be cut out of the polarizer 10 from the strip polarizing plate 12 to face a predetermined direction in the polarizer 10. Thus, in the form in which the polarizing plate 10 is obtained directly from the strip-shaped polarizing plate 12, the polarizing plate 10 can be manufactured more easily.

In the flowchart shown in FIG. 12, it has an absorption axis detecting step S34 of detecting the absorption axis S _A direction of the polarizing plate Intermediate 22. However, the absorption axis detection step S34 may not be provided. Absorption axis S _A direction of the polarizing plate Intermediate 22 are aligned, the direction of the absorption axis S _A in the polarizing plates Intermediate 22 are known by detecting the absorption axis S _A of the strip polarizer 12. Therefore, as in the case shown in FIG. 8, by setting the polarizing plate area A based on the direction of the absorption axis S _A in the polarizer Intermediate 22, as in the case of the end surface processing step S16, the end face machining The polarizing plate 10 may be cut out from the polarizing plate intermediate body 22 by the device 32.

In the embodiment without the absorption axis detecting step S34, for example, polarized light polarizer Intermediate 22 when regarded as a polarizing plate 10, as detected absorption axis S _A direction oriented in a predetermined direction, the belt-shaped polarizing plate 12 The plate intermediate 2 may be cut out. In this case, the absorption axis S _A direction in the polarizer Intermediate 22 is oriented in a predetermined direction of the polarizer 10. For this reason, the end faces 22a to 22d of the polarizing plate intermediate 22 need only be cut with a certain width, so that the end face processing is easy.

  In the flowchart shown in FIG. 12, the polarizing plate intermediate body 22 is cut out from the strip-shaped polarizing plate 12. However, for example, the single-wafer polarizing plate 16 may be cut out from the strip-shaped polarizing plate 12. FIG. 13 is a diagram for explaining a case where a single-wafer polarizing plate is cut out from a strip-shaped polarizing plate based on the detection result of the absorption axis.

In FIG. 13, the top view of the strip | belt-shaped polarizing plate 12 is shown. Further, FIG. 13 shows an example of a detected plurality of absorption axis S _A. As shown in FIG. 13, in the central portion in the width direction of the strip polarizer 12, whereas the direction of the absorption axis S _A is parallel to the longitudinal direction, the width direction near the edge of the strip-shaped polarizer 12, absorption axis S _A is inclined relative to the longitudinal direction. In this case, as shown in FIG. 13 by a two-dot chain line, to set the virtual cutting line regions have all the directions of the absorption axis S _A as the cut-out region of the sheet-fed polarizing plate 16. In one embodiment, as shown in FIG. 13, to set the virtual cutting line so as to face the absorption axis S _A to the longitudinal direction of the sheet polarizer 16. Thus, the absorption axis S _A direction of displacement is smaller leaves polarizing plate 16 may be made. Therefore, if the polarizing plate 10 is manufactured by processing the single-sided polarizing plate 16 on the basis of the direction of the absorption axis S _{A in} the single-sided polarizing plate 16, the polarized light whose absorption axis S _{A is} directed to a predetermined direction. The plate 10 can be manufactured. Further, with respect to sheet polarizer 16 cut out on the basis of a strip-shaped polarizing plate 12 to the absorption axis S _A direction of the detection result, by applying the manufacturing method of the second embodiment, to manufacture the polarizing plate 10 Also good.

(Fourth embodiment)
As a fourth embodiment, a method for manufacturing a liquid crystal panel using the polarizing plate 10 will be described. In the following description, the polarizing plate 10 has the same layer configuration as that of the strip-shaped polarizing plate 12 illustrated in FIG. That is, the polarizing plate 10 includes a polarizer film 12a, protective films 12b and 12c bonded to both surfaces thereof, a surface protective film 12d provided on the protective film 12b, and an adhesive provided in order on the protective film 12c. It has the agent layer 12e and the separate film 12f. Only one of the protective films 12b and 12c may be used.

  Hereinafter, for the convenience of explanation, in the polarizing plate 10 having the layer configuration shown in FIG. 3, the polarizing plate 10 from which the separate film 12f is peeled is also referred to as a polarizing plate 10A.

  FIG. 14 is a drawing schematically showing the configuration of the liquid crystal panel manufactured in the fourth embodiment. As shown in FIG. 14, the liquid crystal panel 46 is configured by laminating a polarizing plate 10 </ b> A obtained by peeling the separate film 12 f from the polarizing plate 10 on both surfaces of a liquid crystal cell 48. As the liquid crystal cell 48, any liquid crystal cell may be used as long as it is used for a known liquid crystal panel. For example, the liquid crystal cell 48 may be one in which a transparent electrode, an alignment film, a liquid crystal, an alignment film, a transparent electrode, a color filter, and a glass substrate are sequentially provided on a glass substrate. Examples of the driving method of the liquid crystal cell 48 are a VA type and an IPS type.

  The liquid crystal panel 46 is manufactured as follows, for example. That is, the polarizing plate 10 is manufactured by the manufacturing method of any polarizing plate disclosed in the first to third embodiments (polarizing plate manufacturing process). Next, the polarizing plate 10 is bonded to both surfaces of the liquid crystal cell 48 to obtain the liquid crystal panel 46 (polarizing plate bonding step).

  In the polarizing plate bonding step, after separating the separate film 12f of each polarizing plate 10, the polarizing plate 10A from which the separate film 12f has been peeled is bonded to the liquid crystal cell 48 via the adhesive layer 12e. When the polarizing plate 10 is bonded to both surfaces of the liquid crystal cell 48, the two polarizing plates 10A are arranged with respect to the liquid crystal cell 48 so that the two polarizing plates 10 are in a crossed Nicols state.

In the manufacturing method, the polarizing plate 10 to be the polarizing plate 10A included in the liquid crystal panel 46 is manufactured by one of the manufacturing methods exemplified in the first to third embodiments. Therefore, the polarizing plate 10, is exactly the absorption axis S _A in a predetermined direction is oriented. Therefore, in the manufactured liquid crystal panel 46, it is possible to improve the image quality when displaying an image.

In addition, when the liquid crystal cell 48 used for manufacturing the liquid crystal panel 46 is either the VA type or IPS type liquid crystal cell 48, an image display with high contrast is possible. Therefore, by applying the polarizer 10A facing exactly absorption axis S _A in a predetermined direction, the liquid crystal panel 46, improvement in the image quality is further improved.

  In 4th Embodiment, the polarizing plate 10 manufactured by the manufacturing method of any polarizing plate disclosed by the 1st-3rd embodiment is at least one of the polarizer film 12a and protective film 12b, 12c. As long as it has. However, the polarizing plate 10 usually has an adhesive layer 12 e for bonding to the liquid crystal cell 48. When the polarizing plate 10 manufactured by any one of the manufacturing methods of polarizing plates disclosed in the first to third embodiments does not have the pressure-sensitive adhesive layer 12e, the polarizing plate 10 and the liquid crystal cell 48 are, for example, an adhesive. May be pasted together, or an adhesive layer may be provided on the liquid crystal cell 48 side.

  Although various embodiments of the present invention have been described above, the present invention is not limited to the illustrated various embodiments, but is shown by the scope of the claims and all within the scope and meaning equivalent to the scope of the claims. Is intended to be included.

  For example, in the first and second embodiments, the process of manufacturing the polarizing plate 10 from the strip-shaped polarizing plate 12 is exemplified. However, in the first embodiment, the single-wafer polarizing plate 16 or the polarizing plate intermediate 22 described in the first embodiment may be purchased, and the polarizing plate 10 may be manufactured therefrom.

  An example has been described in which, when the sheet-shaped polarizing plate 16 is cut out from the band-shaped polarizing plate 12, the rectangular sheet-shaped polarizing plate 16 whose longitudinal direction is the longitudinal direction of the band-shaped polarizing plate 12 is cut out. However, for example, the sheet polarizing plate 16 may be cut out in an oblique direction with respect to the longitudinal direction of the strip-shaped polarizing plate 12. That is, the sheet polarizing plate 16 may be cut out from the strip polarizing plate 12 so that the longitudinal direction of the single polarizing plate 16 and the longitudinal direction of the strip polarizing plate 12 intersect. Moreover, the planar view shape of the single wafer polarizing plate 16 is not limited to a rectangle or a square, For example, a parallelogram may be sufficient. Here, although the modification in the case of cutting out the sheet polarizing plate 16 from the strip-shaped polarizing plate 12 has been described, the same applies to the case of cutting out the polarizing plate intermediate 22 from the sheet polarizing plate 16.

  The planar view shape of the polarizing plate 10 is illustrated as a rectangle such as a rectangle or a square, but is not limited to a rectangle and may be a circle.

  When the polarizing plate 10 is cut directly from the strip-shaped polarizing plate 12 or when the polarizing plate intermediate body 22 is cut out, the number of the polarizing plates 10 and the polarizing plate intermediate body 22 is not limited to two, that is, two or more, but may be one. Similarly, when the polarizing plate 10 is directly cut out from the single-wafer polarizing plate 16 or when the polarizing plate intermediate body 22 is cut out, the number of the polarizing plates 10 and the polarizing plate intermediate bodies 22 is not limited to two, that is, two or more. It may be a sheet.

  Examples of the driving method of the liquid crystal panel to which the polarizing plate 10 is applied are not limited to the VA type and the IPS type. For example, the driving method of the liquid crystal panel to which the polarizing plate 10 is applied may be a TN (Twisted Nematic) method.

  DESCRIPTION OF SYMBOLS 10 ... Polarizing plate, 12 ... Band-shaped polarizing plate (polarizing plate original plate), 12a ... Polarizer film, 16 ... Single-wafer polarizing plate (polarizing plate original plate), 22 ... Polarizing plate intermediate body (polarizing plate original plate), 46 ... Liquid crystal panel 48 ... Liquid crystal cell.

In one embodiment, the processing steps include an intermediate cutting step for cutting out a polarizing plate intermediate from a polarizing plate original plate, an intermediate absorption axis detecting step for detecting the direction of the absorption axis of the polarizing plate intermediate, and a polarizing plate intermediate Cutting the end face of the substrate, and in the intermediate cutting step, the direction of the absorption axis of the polarizing plate original plate detected in the original plate absorption axis detection step is the same in the polarizing plate intermediate to be obtained In addition, in the step of cutting the polarizing plate original plate and cutting the end face of the polarizing plate intermediate, the direction of the absorption axis of the polarizing plate intermediate detected in the intermediate absorption axis detection step is in the polarizing plate to be obtained. You may cut the end surface of a polarizing plate intermediate body so that it may face the predetermined direction.

In the form in which the polarizing plate original plate is a band-shaped polarizing plate, the processing steps in the method for manufacturing a polarizing plate include an intermediate cutting step of cutting out the polarizing plate intermediate from the polarizing plate original plate, and detecting the direction of the absorption axis of the polarizing plate intermediate The intermediate absorption axis detecting step and the step of cutting the end face of the polarizing plate intermediate, and in the intermediate cutting step, the direction of the absorption axis of the polarizing plate original plate detected in the original plate absorption axis detecting step In the step of cutting the polarizing plate original plate and cutting the end face of the polarizing plate intermediate so as to be the same in the polarizing plate intermediate to be obtained, the polarizing plate intermediate detected in the intermediate absorption axis detection step The end face of the polarizing plate intermediate may be cut so that the direction of the absorption axis of the polarizing plate faces the predetermined direction in the polarizing plate to be obtained.

Claims (13)

A method of manufacturing a polarizing plate in which the direction of the absorption axis is directed to a predetermined direction,
An original plate absorption axis detecting step for detecting the direction of the absorption axis in the polarizing plate original plate,
A processing step of obtaining a polarizing plate by processing the polarizing plate original plate,
With
In the processing step, the polarizing plate original plate is processed so that the direction of the absorption axis of the polarizing plate original plate detected in the original plate absorption axis detection step faces the predetermined direction in the polarizing plate to be obtained.
Manufacturing method of polarizing plate. In the processing step, the end surface of the polarizing plate original plate is cut so that the absorption axis direction of the polarizing plate original plate detected in the original plate absorption axis detection step faces the predetermined direction of the polarizing plate to be obtained. ,
The manufacturing method of the polarizing plate of Claim 1. A single-wafer cutting step of cutting the single-wafer polarizing plate from the strip-shaped polarizing plate;
An intermediate cutting step of cutting out the polarizing plate intermediate that is the polarizing plate original plate from the single-wafer polarizing plate;
Further comprising
The manufacturing method of the polarizing plate of Claim 2. In the processing step, the polarizing plate original plate is cut so that the direction of the absorption axis of the polarizing plate original plate detected in the original plate absorption axis detection step faces the predetermined direction in the polarizing plate to be obtained.
The manufacturing method of the polarizing plate of Claim 1. The processing step is
An intermediate cutting step of cutting out a polarizing plate intermediate from the polarizing plate original plate,
An intermediate absorption axis detecting step for detecting the direction of the absorption axis of the polarizing plate intermediate;
Cutting the end face of the polarizing plate intermediate; and
Have
In the intermediate cutting step, the polarizing plate original plate is cut so that the absorption axis direction of the polarizing plate original plate detected in the original plate absorption axis detecting step is the same in the polarizing plate intermediate to be obtained. ,
In the step of cutting the end face of the polarizing plate intermediate, the direction of the absorption axis of the polarizing plate intermediate detected in the intermediate absorption axis detecting step faces the predetermined direction in the polarizing plate to be obtained. So as to cut the end face of the polarizing plate original plate,
The manufacturing method of the polarizing plate of Claim 1.   The manufacturing method of the polarizing plate of Claim 4 or 5 further equipped with the single wafer cutting process which cuts out the single wafer polarizing plate which is the said polarizing plate original plate from a strip | belt-shaped polarizing plate. The polarizing plate original plate is a strip-shaped polarizing plate,
In the processing step, the polarizing plate original plate is cut and processed so that the direction of the absorption axis of the polarizing plate original plate detected in the original plate absorption axis detection step faces the predetermined direction.
The manufacturing method of the polarizing plate of Claim 1. The processing step is
An intermediate cutting step of cutting out a polarizing plate intermediate from the polarizing plate original plate,
An intermediate absorption axis detection step for detecting the direction of the absorption axis of the polarizing plate intermediate; and
Cutting the end face of the polarizing plate intermediate; and
Have
In the intermediate cutting step, the polarizing plate original plate is cut so that the direction of the absorption axis of the polarizing plate original plate detected in the original plate absorption axis detecting step is the same in the polarizing plate intermediate to be obtained. And
In the step of cutting the end face of the polarizing plate intermediate, the direction of the absorption axis of the polarizing plate intermediate detected in the intermediate absorption axis detecting step faces the predetermined direction in the polarizing plate to be obtained. So as to cut the end face of the polarizing plate original plate,
The manufacturing method of the polarizing plate of Claim 1.   The method for producing a polarizing plate according to claim 3, wherein the strip-shaped polarizing plate includes a uniaxially stretched polarizing layer.   The manufacturing method of the polarizing plate of Claim 9 whose width | variety of the said strip | belt-shaped polarizing plate is 1000 mm or more. The planar view shape of the polarizing plate is rectangular or square,
The length of the diagonal line of the polarizing plate is 350 mm or less,
The manufacturing method of the polarizing plate as described in any one of Claims 1-10.   The said polarizing plate is a manufacturing method of the polarizing plate as described in any one of Claims 1-11 which is a polarizing plate for liquid crystal panels of a VA type or an IPS type. A polarizing plate is manufactured by the manufacturing method of the polarizing plate as described in any one of Claims 1-12, and a liquid crystal panel is manufactured by bonding the obtained polarizing plate to a liquid crystal cell.
A method for manufacturing a liquid crystal panel.

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