JP2008058557A - Optical film attaching method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical film attaching method for conveniently and exactly attaching an optical film by a marking corresponding to the need of an operator. <P>SOLUTION: The optical film attaching method relates to a method of attaching a polarizer 13 having a protective sheet 24 on one side surface to a liquid crystal display cell 12. The optical film attaching method includes: a step of attaching a liquid crystal display cell 12 to the surface of the polarizer 13 opposite to the surface having the protective sheet 24 of the polarizer 13; and a step of peeling the protective sheet 24 of the polarizer 13 attached to the liquid crystal display cell 12. Therein, micro characters are applied on the protective sheet 24. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an optical film sticking method for a polarizing plate or the like, for example, an optical film sticking method for sticking a polarizing plate having a protective sheet on one surface to a display cell.

  Liquid crystal display devices (LCDs) are widely used as flat panel displays in the era of information communication, for OA, consumer, and industrial applications, taking advantage of their thin, lightweight, and low power consumption features. As a liquid crystal display method used in the liquid crystal display device, there are an STN (super twisted nematic) method, a TN (twisted nematic) method, an IPS (in-plane switching) method, and the like.

  These liquid crystal display elements use polarizing plates in order to utilize the optical rotation and birefringence of light associated with the alignment state of liquid crystals. The polarizing plate is generally made by stretching a polyvinyl alcohol (PVA) film and dyeing it with a dichroic dye such as iodine. And the surface is laminated | stacked by protective films, such as a triacetyl cellulose (TAC). This polarizing plate is an optical film having a polarization function of transmitting light oscillated in a certain direction and absorbing light oscillated in an orthogonal direction. The liquid crystal display panel is generally configured to display an image by attaching two types of polarizing plates having different polarization axes to the front surface and the back surface, which are display surfaces.

  Optical films such as polarizing plates and retardation plates, and elliptically polarizing plates laminated with them are usually used for transportation, storage, assembly, etc. in a state where they are adhesively coated with a protective sheet so that the surface is not damaged. . Further, since it is difficult to understand that the protective sheet is adhesively coated, there are cases where forgetting to remove the protective sheet occurs. For this reason, forgetting to peel off is prevented by marking a line etc. on a protection sheet.

  With the active commercialization of liquid crystal display devices, various types of polarizing plates have been adopted. A liquid crystal display cell used in a liquid crystal display device has polarizing plates attached to both sides of a panel. In addition to the polarization axis, the front surface (F polarizing plate) and the back surface (R polarizing plate) may have different surface treatments for preventing reflection on the front surface and preventing scratches. As described above, since the types of the polarizing plates are different for the front side and the rear side, it is necessary to attach the polarizing plate so as not to mistake the type. Furthermore, the polarizing plate has an axial direction, and a liquid crystal display device installed by mistake is not able to exhibit the function as a liquid crystal display device. However, the polarizing plate is the same transparent film in appearance even if the specifications are slightly different. For this reason, for example, when a polarizing plate is delivered from a polarizing plate manufacturer, product information such as the product number is described in the polarizing plate packaging bag. It is difficult to distinguish from above. In addition, since the surface of the polarizing plate is covered with a protective sheet, it is more difficult to distinguish between the front side and the rear side in appearance.

  For this reason, there are cases where the same type of polarizing plate is mistakenly attached to both surfaces of the cell, or the front and back surfaces are attached in reverse. When such a work mistake occurs, there arises a problem of increasing the number of work steps, such as peeling off a wrongly attached polarizing plate and then attaching another polarizing plate. Further, when the polarizing plate is peeled off, static electricity is generated to break the liquid crystal display cell, resulting in a decrease in the yield of the liquid crystal display panel.

In order to solve such a problem, a technique is disclosed in which a protective sheet attached to the surface of a polarizing plate is labeled so that the type of polarizing plate can be distinguished (Patent Document 1). This indicates the axial direction and the like on the protective sheet affixed to the surface of the polarizing plate, and prevents the polarizing plate from being mistakenly attached.
JP 2003-14934 A

  In other words, the protective sheet for the polarizing plate requires the marking for preventing forgetting to peel as described above and the marking capable of preventing the wrong attaching of the polarizing plate as in the technique of Patent Document 1. However, a manufacturer that manufactures a liquid crystal display panel needs markings that can prevent mistakes in attaching the polarizing plate, but an assembly manufacturer that assembles a liquid crystal display device using an assembled liquid crystal display panel does not have such markings. It is unnecessary. Instead, the assembly manufacturer needs a more comprehensible marking, such as a line marked by magic. In other words, necessary markings and unnecessary markings differ depending on each manufacturer. For this reason, it is difficult to obtain markings according to the needs of the operator.

  This invention is made | formed in view of said problem, and it aims at obtaining the optical film sticking method convenient and correctly affixed by the marking according to an operator's needs.

  The optical film sticking method according to the present invention is an optical film sticking method for sticking an optical film having a protective sheet on one surface to a display cell, the opposite surface of the optical film having the protective sheet, A step of affixing a display cell; and a step of peeling off the protective sheet of the optical film affixed to the display cell, wherein microcharacters representing product number identification of the optical film are repeatedly arranged on the protective sheet. In this method, line marking is applied. Thereby, it can be simply and accurately applied by marking according to the needs of the operator.

  A plurality of the line-shaped markings may be aligned. Furthermore, the line-shaped marking may be an alignment mark with the display cell.

  According to the present invention, the optical film can be simply and accurately attached by marking according to the needs of the operator.

Embodiment.
Before describing an optical film attaching method for attaching an optical film such as a polarizing plate or a retardation plate according to the present invention to a display cell, a display device will be described. The display device is a flat display device (flat panel display) such as a liquid crystal display device or an organic EL display device. Here, as an example, a liquid crystal display device will be described with reference to FIG. FIG. 1 is a cross-sectional view illustrating a configuration of a liquid crystal display panel used in a liquid crystal display device. In a liquid crystal display device, a backlight unit or the like is attached to a liquid crystal display panel in which an optical film such as a polarizing plate is attached to the front and back surfaces of a liquid crystal display cell.

  As shown in FIG. 1, the liquid crystal display cell 12 includes a TFT array substrate 1 and a counter substrate 2 disposed so as to face the TFT array substrate 1 at the outer periphery of the TFT array substrate 1. The liquid crystal layer 4 is formed and sealed between them. The TFT array substrate 1 includes a TFT (thin film transistor) 5 as a switching element, and the pixel electrode 6 is disposed almost entirely except for the TFT 5 in a region surrounded by the sealant 3. A TCP (Tape Carrier Package) 7 provided with a drive circuit is connected to an end of the TFT array substrate 1 via an ACF (Anisotropic Conductive Film) 8. Thereby, various signals from the outside are supplied. In response to these signals, ON / OFF of the TFT 5 is controlled. When the TFT 5 is in the ON state, a display voltage is applied to the pixel electrode 6.

  The counter substrate 2 has a color filter layer and a counter electrode 9. The color filter layer includes, for example, a black matrix (BM) 10 and a colored layer 11 of red (R) green (G) blue (B). The counter electrode 9 is arranged on the liquid crystal layer 4 side of the counter substrate 2 and applies a common potential for supplying a signal potential to the liquid crystal layer 4. A color filter layer is formed between the counter substrate 2 and the counter electrode 9 in a region facing the pixel electrode 6 and the TFT 5, and color display is performed using the color filter layer.

  A liquid crystal alignment film (not shown) for aligning the liquid crystal is formed on the surface of the TFT array substrate 1 and the counter substrate 2 on the liquid crystal layer 4 side. Then, a polarizing plate 13 is attached to the outside of the TFT array substrate 1 and the counter substrate 2 to form a liquid crystal display panel 14. That is, the polarizing plate 13 is attached to the front and back surfaces of the liquid crystal display cell 12. Here, details of the polarizing plate 13 will be described later. The liquid crystal display panel 14 having such a structure is called a two-polarizing plate type, but there is also a one-polarizing plate type. In the STN (super twisted nematic) system, a retardation plate is usually attached in addition to the polarizing plate 13. A backlight unit (not shown) or the like is attached to the liquid crystal display panel 14. The liquid crystal display device is configured as described above. Moreover, said structure is an example and a structure other than this may be sufficient.

  Here, when a display voltage is applied to the pixel electrode 6, an electric field corresponding to the display voltage is generated between the pixel electrode 6 and the counter electrode 9. The liquid crystal is driven by the electric field between the pixel electrode 6 and the counter electrode 9. That is, the alignment direction of the liquid crystal between the substrates changes. As a result, the polarization state of the light passing through the liquid crystal layer 4 changes. That is, the polarization state of the light that has passed through the polarizing plate 13 and becomes linearly polarized light is changed by the liquid crystal layer 4. Specifically, the light from the backlight unit becomes linearly polarized light by the polarizing plate 13 on the TFT array substrate 1 side. Then, when the linearly polarized light passes through the liquid crystal layer 4, the polarization state changes.

  Accordingly, the amount of light passing through the polarizing plate 13 on the counter substrate 2 side varies depending on the polarization state. That is, the amount of light that passes through the polarizing plate 13 on the viewing side in the transmitted light that passes through the liquid crystal display panel 14 from the backlight unit changes. The alignment direction of the liquid crystal changes depending on the applied display voltage. Therefore, the amount of light passing through the viewing-side polarizing plate 13 can be changed by controlling the display voltage. That is, a desired image can be displayed by changing the display voltage for each pixel.

  Next, the polarizing plate 13 will be described with reference to FIG. FIG. 2 is a cross-sectional view showing a configuration of a general polarizing plate 13. The configuration of the polarizing plate 13 differs depending on whether the liquid crystal display device is a transmissive type, a semi-transmissive type, or a reflective type. Here, the configuration of the transmissive polarizing plate 13 will be described.

  The polarizing plate 13 is composed of a polarizing substrate 20 containing a polarizer and a base substrate 21. Base substrates 21 are provided on both surfaces of the polarizing substrate 20, and the base substrate 21 protects the polarizing substrate 20. As the polarizing substrate 20, a polarizing substrate (for example, polyvinyl alcohol: PVA) containing iodine or a dichroic dye as a polarizer can be used. As the base substrate 21, transparent triacetyl cellulose (TAC) can be used. TAC is preferable because it has excellent water resistance and does not warp or deteriorate due to moisture remaining in the polarizing plate. An adhesive layer 22 and a release sheet 23 are sequentially provided on the surface of one base substrate 21. Therefore, when the release sheet 23 is peeled off, the adhesive layer 22 is exposed and the polarizing plate 13 can be attached to the liquid crystal display cell 12. Further, a protective sheet 24 is provided on the other surface of the base substrate 21 opposite to the surface on which the polarizing substrate 20 is provided. This is provided to protect the polarizing plate 13. The polarizing plate 13 is configured as described above. The polarizing plate 13 is an optical film having a polarizing function of transmitting light oscillating in a certain direction and absorbing light oscillating in an orthogonal direction.

  The present invention is characterized by the protective sheet 24 affixed to the polarizing plate 13. Therefore, the protective sheet 24 will be described next with reference to FIG. FIG. 3 is a perspective view showing the configuration of the liquid crystal display panel 14 to which the polarizing plate 13 is attached. That is, FIG. 3 is a view of the liquid crystal display panel 14 shown in FIG. 1 as viewed obliquely. The configuration of the liquid crystal display panel 14 is the same as that in FIG.

  The polarizing plate 13 and the liquid crystal display cell 12 are attached by the adhesive layer 22 shown in FIG. Further, as described above, the protective sheet 24 is attached to the surface of the polarizing plate 13. A marking 25 is provided on the surface of the protective sheet 24. In the present embodiment, the marking 25 is a micro character having a width or height of 0.01 to 1 mm. And the product number of the polarizing plate 13 which shows product number identification by a micro character is repeatedly arranged on the surface of the protective sheet 24, and the line-shaped marking 25 is given. Depending on the product number, the type of the polarizing plate 13, for example, for the front side, for the back side, size, and specification can be identified. These micro characters can be confirmed by a microscope or the like. Moreover, it is preferable that the color of the micro characters is a warm color system such as red and yellow so that it can be easily identified in order to prevent forgetting to remove the protective sheet 24. In order to further increase the discriminating power, the line-shaped marking 25 is preferably a line group in which 10 to 100 lines are bundled. Further, it is preferable that a plurality of line groups are aligned.

  Next, the optical film sticking method according to the present embodiment will be described with reference to FIG. Here, a polarizing plate is used as an example of the optical film. FIG. 4 is a flowchart showing a polarizing plate attaching method.

  First, the protective sheet 24 with the marking 25 is stuck on the base substrate 21 constituting the polarizing plate 13 (step S1). Next, the peeling sheet 23 of the polarizing plate 13 is peeled (step S2). As a result, the adhesive layer 22 is exposed. And the liquid crystal display cell 12 and the polarizing plate 13 are bonded together by the adhesion layer 22 (step S3). That is, the opposite surface of the polarizing plate 13 having the protective sheet 24 and the liquid crystal display cell 12 are attached. And the protective sheet 24 of the polarizing plate 13 stuck on the liquid crystal display cell 12 is peeled (step S4). Through the above steps, the polarizing plate 13 having the protective sheet 24 on one surface is attached to the liquid crystal display cell 12.

  In the present embodiment, line-shaped markings 25 made of micro characters are provided on the protective sheet 24 of the polarizing plate 13. Since the product number is written in this micro character, it is possible to prevent conventional confusion. That is, it is possible to reduce mistakes in pasting polarizing plates as in the past. Moreover, if such a protection sheet 24 is used, it can cut | disconnect in the arbitrary locations of the protection sheet 24. FIG. This is because the description of the product number is unlikely to be interrupted because the characters are as small as a micro size. As a result, the product number can be confirmed regardless of where it is cut. Furthermore, by using the micro characters for the marking 25, it is recognized as a line by the naked eye. Thereby, forgetting to peel off the protective sheet 24 can be prevented. That is, the marking 25 written by micro characters is also used as a mark for preventing forgetting to peel off. Thereby, in the manufacturer which manufactures the liquid crystal display panel 14, the product number of a polarizing plate can be confirmed. An assembly manufacturer that assembles a liquid crystal display device using the assembled liquid crystal display panel 14 can reduce forgetting to remove the protective sheet 24 of the polarizing plate 13. In this way, the same marking 25 can be used in two ways: confirmation of the product number of the polarizing plate 13 and prevention of forgetting to remove the protective sheet 24.

  In addition, the manufacturer needs the product number of the polarizing plate 13, but the assembly manufacturer does not need the product number. As described above, since the micro characters are used for the marking 25, when the protective sheet 24 is peeled off by the assembly maker, the product number is not known. Moreover, as shown in FIG. 3, it can be seen that the protective sheet 24 is affixed at a glance because the micro characters are applied in a line shape. For example, line-shaped markings can be formed by repeatedly printing micro characters indicating the product number of the polarizing plate in a line. On the other hand, a manufacturer who needs the product number of the polarizing plate 13 can confirm the product number by using a microscope or the like. Thus, the same marking 25 can be used properly according to the needs of the manufacturer and assembly manufacturer. According to the present embodiment, it is possible to reduce forgetting to remove the protective sheet provided on the surface of the polarizing plate while preventing mistakes in attaching the polarizing plate. That is, it can be applied simply and accurately by the marking 25 according to the needs of the operator. Moreover, since the several line-shaped marking 25 is formed in the whole surface of the protection sheet 24, the protection sheet 24 can be cut | disconnected in arbitrary places. The line-shaped marking 25 is preferably formed in the same direction as the polarization axis direction of the polarizing plate 13.

  The shape of the marking 25 does not have to be formed in a diagonal line as shown in FIG. That is, it may be formed in any shape. Furthermore, the line-shaped marking 25 can be used as an alignment mark with the liquid crystal display cell 12. For example, the polarizing plate 13 can be accurately bonded to the liquid crystal display cell 12 by marking the display area on the protective sheet 24 and aligning it with the display area of the liquid crystal display cell 12. The marking 25 is not particularly limited, and one type or two or more types of letters, numbers, figures, pictures, and the like can be combined. By describing these in the micro size, the same effect as in the present embodiment can be obtained. Further, the present invention can be applied to optical films other than the polarizing plate 13, such as a retardation plate, an elliptical polarizing plate in which the polarizing plate 13 and the retardation plate are laminated, or a color filter. Here, the liquid crystal display cell 12 is used as a display cell to be bonded to an optical film such as a polarizing plate, but other display cells such as an organic EL display cell may be used.

It is sectional drawing which shows the structure of the liquid crystal display panel concerning embodiment. It is sectional drawing which shows the structure of the polarizing plate concerning embodiment. It is a perspective view which shows the structure of the liquid crystal display panel concerning embodiment. It is a flowchart which shows the polarizing plate sticking method concerning embodiment.

Explanation of symbols

1 TFT array substrate, 2 counter substrate, 3 sealant, 4 liquid crystal layer,
5 TFT, 6 pixel electrode, 7 TCP, 8 ACF, 9 counter electrode,
10 BM, 11 colored layer, 12 liquid crystal display cell, 13 polarizing plate,
14 Liquid crystal display panel,
20 polarizing substrate, 21 base substrate, 22 adhesive layer, 23 release sheet,
24 protective sheet, 25 marking

Claims (3)

An optical film sticking method for sticking an optical film having a protective sheet on one surface to a display cell,
The step of pasting the display cell and the opposite surface of the optical film having the protective sheet;
The step of peeling the protective sheet of the optical film affixed to the display cell,
An optical film sticking method in which micro characters representing the product number identification of the optical film are repeatedly arranged on the protective sheet to form a line-shaped marking.   The optical film sticking method according to claim 1, wherein a plurality of the line-shaped markings are aligned.   The optical film sticking method according to claim 1, wherein the line-shaped marking becomes an alignment mark with the display cell.

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