METHOD FOR MANUFACTURING OPTICAL DISPLAY DEVICE

Abstract

A method for manufacturing an optical display device from a web of optical film laminate including a carrier film, a pressure-sensitive adhesive layer formed on one of opposite surfaces of the carrier film, and a plurality of sheets of optical functional film continuously supported on the carrier film via the pressure-sensitive adhesive layer, comprises folding the other of opposite surfaces of the carrier film inside via a tip end of a releasing body to wind the carrier film, peeling the sheet of optical functional film to a head-out state while exposing the pressure-sensitive adhesive layer, stopping winding of the carrier film, detecting a front end of the peeled sheet of optical functional film in the head-out state, and rewinding the carrier film integrally with the sheet of optical functional film in the head-out state to mend a deformation of a pressure-sensitive adhesive, at the tip end of the releasing body.

Claims

1. A method for manufacturing an optical display device from a web of optical film laminate including a carrier film, a pressure-sensitive adhesive layer formed on one of opposite surfaces of the carrier film, and a plurality of sheets of optical functional film continuously supported on the carrier film via the pressure-sensitive adhesive layer, by peeling the sheet of optical functional film together with the pressure-sensitive adhesive layer from the carrier film of the web of optical film laminate, and laminating the peeled sheet of optical functional film with a corresponding one of panel members at a laminating position, the method comprising steps of: folding the other of opposite surfaces of the carrier film inside at a tip end of a releasing body having the tip end arranged at a position facing the laminating position, to wind the carrier film, and peeling the sheet of optical functional film together with the pressure-sensitive adhesive layer to a head-out state from the carrier film, when a front end of the sheet of optical functional film in the head-out state reaches a detecting position between a peeling position, where the sheet of optical functional film is peeled from the carrier film at the tip end, and the laminating position, winding of the carrier film is stopped for detecting the front end, after the front end is detected, winding and hooking the carrier film around the releasing body to be rewound to backwardly feed the sheet of optical functional film in the head-out state with the pressure-sensitive adhesive layer to mend a deformation of a pressure-sensitive adhesive of the pressure-sensitive adhesive layer, at the tip end of the releasing body, generated at the peeling position of the pressure-sensitive adhesive layer peeled to the head-out state and exposed, conveying a panel member to be laminated with the sheet of optical functional film from a waiting position to the laminating position, after the pressure-sensitive adhesive layer is mended, winding the carrier film again, peeling the sheet of optical functional film with the mended pressure-sensitive adhesive layer from the carrier film to feed the front end to the laminating position, and when the front end reached the laminating position, laminating the sheet of optical functional film with corresponding one of the panel members via the pressure-sensitive adhesive layer by a laminating unit.

2. The method according to claim 1, wherein winding and hooking the carrier film around the releasing body to backwardly feed the sheet of optical functional film in the head-out state with the pressure-sensitive adhesive layer includes backwardly feeding the sheet of optical functional film until the front end reaches a backwardly fed position upstream of the tip end of the releasing body from the detecting position.

3. The method according to claim 1, wherein winding and hooking the carrier film around the releasing body for rewinding includes rewinding the carrier film at a steady tension to laminate the sheet of optical functional film in the head-out state again on the rewound carrier film with the mended pressure-sensitive adhesive layer.

4. The method according to claim 1, wherein the detecting position is configured as a position which is 10 mm or more to 30 mm or less from the tip end facing the laminating position, and which does not reach the laminating position.

5. The method according to claim 1, wherein a distance which the carrier film is rewound after the front end is detected is a distance between the peeling position and the detecting position or longer.

6. The method according to claim 1, wherein a thickness of the sheet of optical functional film is in a range of 45 m to 85 m, and a thickness of the pressure-sensitive adhesive layer is 20 m to 30 m.

Description

BRIEF DESCRIPTION OF DRAWINGS

[0036] FIG. 1 is an overview of a manufacturing apparatus for manufacturing an optical display device.

[0037] FIG. 2 (a) and FIG. 2 (b) show a deformation of a pressure-sensitive adhesive of a pressure-sensitive adhesive layer.

[0038] FIG. 3 is a structure of an optical film laminate.

[0039] FIG. 4 is an operation flow.

[0040] FIG. 5 (a), FIG. 5 (b) and FIG. 5 (c) show configurations and a Table of results of Examples and Comparative Examples.

[0041] FIG. 6 (a), FIG. 6 (b) and FIG. 6 (c) show cause analysis diagrams of the deformation of the pressure-sensitive adhesive layer and experimental results.

DESCRIPTION OF EMBODIMENTS

[Cause of Generation of Deformation by Pressure-Sensitive Adhesive of Pressure-Sensitive Adhesive Layer]

[0042] As apparent from an operation flow of FIG. 4, from Step 1 in which the optical film laminate 1 is drawn from a roll arranged in the manufacturing apparatus 10, Step 2 succeeds in which slit lines are formed in a width direction to form a size of the panel member 5 on an optical film part 3 of the optical film laminate 1 being conveyed so that a plurality of sheets of optical functional film 3 on the carrier film 2 are formed, and the carrier film 2 is wound at the tip end 61 of the releasing body 60, and winding of the carrier film 2 is stopped where the sheet of optical functional film 3 is peeled from the carrier film 2 in a head-out state. Such stopping of winding leads to Step 3 in which the front end 31 of the sheet of optical functional film 3 is detected in a head-out state. Detection of the front end 31 is a step of storing a position of the front end in a storage device (not shown), and computing a deviated distance from the panel member using the stored information to adjust a deviated position of the panel member. The preceding steps are steps for manufacturing the optical display device 6 by the RTP manufacturing apparatus 10 also described in Patent Literature 5.

[0043] FIG. 6 (a) and FIG. 6(b) show cause analysis diagrams of the deformation of the pressure-sensitive adhesive layer. The cause of the deformation of the pressure-sensitive adhesive layer is apparent from schematic diagrams in FIG. 6 (a) and FIG. 6 (b). For the sheet of optical functional film shown in FIG. (a) which is without the head-out state for alignment, as shown in Table in FIG. 6 (c), the linear deformation is not generated on the pressure-sensitive adhesive layer. However, for the sheet of optical functional film in FIG. 6 (b) in the head-out state for alignment, as shown in Table in FIG. 6 (c), a head-out distance and a distance between a position where the linear deformation generated and the front end of the film matches. The peeling position for the peeling at the tip end 61 of the releasing body 60 is the position where the linear deformation is generated.

[0044] Step 5 of FIG. 4 is a step of mending the generated linear deformation. After the front end 31 is detected with the sheet of optical functional film 3 in the head-out state of FIG. 6 (b), the sheet of optical functional film 3 in the head-out state and the carrier film 2 are wound and hooked around the releasing body 60 by second feed rollers 82 of the film conveying device 80 so that a certain distance is rewound. Such back feeding pushes the bulged deformation of the pressure-sensitive adhesive generated at the peeling position 300 back at the tip end of the releasing body 60 to be mended. Needless to say, a head-out time for detection is very short in relation to a tact time, and the back feeding in a fairly early timing improves mending accuracy. Next, in Step 6, the film conveying unit 80 is actuated again to wind the carrier film 2 and feed the front end 31 of the sheet of optical functional film 3 to the laminating position 100, and in Step 7, it is laminated with the separately conveyed panel member 5 to complete the optical display device 6.

Examples and Comparative Examples

[0045] FIG. 5 (a) shows the sheet of optical functional film in the head-out state in which the carrier film 2 is being wound and peeled, and FIG. 5 (b) shows the sheet of optical functional film being rewound integrally with the carrier film 2 to the backwardly fed position 400. FIG. 5 (c) shows Examples and Comparative Examples visually checked as such.

[0046] Each of Examples 1 to 3 is of the sheet of optical functional film shown in FIG. 3 (b) having the thinnest thickness, and Example 4 is based on the thickness of the sheet of optical functional film also shown in FIG. 3 (b). All of the films are visually checked through a backlight as to whether the linear deformation 40 is generated in the optical display device 6, and it was not recognized.

[0047] Comparative Example 1 is of a thickness of the optical functional film used in Examples 1 to 3, and when the optical display device 6 is visually checked, which is manufactured by feeding the sheet of optical functional film peeled integrally with the carrier film 2 to the head-out state to the laminating position 100 without rewinding, the linear deformation 40 was recognized. Comparative Example 2 is of the sheet of optical functional film 3 having a thickness the same as Example 4, and when an optical display device fed to the laminating position 100 also without rewinding is visually checked, the linear deformation 40 was also recognized.

[0048] Reference Example 4 is a result of a visual check which is the same as Comparative Examples using the optical film of FIG. 3 (a) having a conventional thickness. Here, a thickness of the sheet of optical functional film is 280 m, and a winding process therefor does not exist. The linear deformation 40 was visually checked, but it was not recognized in terms of results.

REFERENCE SIGNS LIST

[0049] 1: Optical film laminate [0050] 2: Carrier film [0051] 3: Sheet of optical functional film [0052] 3: Part of optical film before forming slit lines [0053] 31: Front end of sheet of optical functional film [0054] 32: Rear end of sheet of optical functional film [0055] 4: Pressure-sensitive adhesive layer [0056] 41: Pressure-sensitive adhesive [0057] 40: Deformation by pressure-sensitive adhesive of pressure-sensitive adhesive layer [0058] 5: Panel member [0059] 6: Optical display device [0060] 10: RTP manufacturing apparatus [0061] 20: Controlling unit [0062] 50: Laminating unit [0063] 60: Releasing body [0064] 61: Tip end of releasing body [0065] 70: Detecting unit [0066] 80: Film conveying unit [0067] 81: First feed rollers [0068] 82: Second feed rollers [0069] 83: Third feed rollers [0070] 90: Panel member conveying unit [0071] 100: Laminating position [0072] 200: Detecting position [0073] 300: Peeling position [0074] 400: Backwardly fed position [0075] 500: Waiting position of panel member