As an example of optical display units mounted on liquid crystal display devices or the like, there is an optical display unit having a structure such that an optical sheet piece including an optical film such as a polarizing film is bonded onto one surface or both surfaces of a display substrate. Conventionally, as a method for manufacturing such an optical display unit, there is known a method including a step of manufacturing pieces of sheet material by feeding a sheet material from a material roll made by winding the sheet material in which a release film (first base film) is bonded onto a long optical sheet including an optical film, and sequentially cutting the sheet material along the width direction at an interval that corresponds to the size of the display substrate. Then, by peeling the first base film from the produced piece of sheet material, an optical sheet piece having a first pressure-sensitive adhesive layer on the surface is obtained, and the optical sheet piece is bonded onto the display substrate with the first pressure-sensitive adhesive layer interposed therebetween. As described above, the first base film is peeled off at the time of bonding the optical sheet piece to the display substrate, thereby providing a composition that can be peeled off in a comparatively easy manner.
Typically, by a conventional method of manufacturing an optical display unit as described above, pieces of sheet material produced by a film maker are packaged and transported to a panel processing manufacturer, and are subjected to unpacking and bonded to each display substrate by the panel processing manufacturer. The above packaging work is a necessary work because the film maker and the panel processing manufacturer are located at different positions; however, the work is cumbersome and also raises a problem in that scratches or contaminations are likely to generate in the pieces of sheet material at the time of transportation or the like.
In contrast, according to a technique disclosed in Japanese Unexamined Patent Publication No. 2007-140046 (Patent Document 1), a step of feeding a long sheet material from a material roll and cutting the sheet material and a step of bonding the cut piece of sheet material onto a display substrate are performed on a continuous production line. Accordingly, as compared with a conventional method in which the pieces of sheet material are packaged, the operation can be facilitated and the scratches or contaminations which may generate at the time of transportation or the like can be suppressed.