System and method for manufacturing optical display

The invention relates to systems and methods for manufacturing optical displays. More specifically, the invention relates to a system and method for manufacturing an optical display including a laminate of a belt- or sheet-shaped product and an optical display unit.

According to conventional techniques, optical film makers manufacture a roll of a belt and sheet-shaped product having an optical film component in a continuous manner. Examples of the “belt and sheet-shaped product” include a raw polarizing plate, a raw retardation plate, and a raw laminated film of a polarizing plate and a retardation plate each for use in liquid crystal displays. The optical film component is supplied to panel makers who assemble the optical film component (such as a polarizing plate and a retardation plate) and an optical display unit (such as a sealed glass substrate unit containing a liquid crystal cell) from the optical film makers. The optical film makers punch a desired size pieces, which is desired by the panel makers, from the belt and sheet-shaped product and pack a pile of several punched sheet-shaped product pieces for delivery.

A pressure-sensitive adhesive is used to stick the sheet-shaped product to the optical display unit. The pressure-sensitive adhesive is previously provided as a layer on the sheet-shaped product, and a release film is further provided to protect the pressure-sensitive adhesive layer. In the process of punching pieces from the sheet-shaped product, therefore, the pressure-sensitive adhesive layer can be squeezed out of the punched section. When a pile of several pieces is packed, the squeezing out of the pressure-sensitive adhesive layer (pressure-sensitive adhesive) can cause sticking of the layered sheet-shaped products and can further cause scratches or stains on the surface of the sheet-shaped products to degrade the quality. Against the problem, it is proposed that the end face of the sheet-shaped product should be worked after the punching so that the influence of the squeezing out of the pressure-sensitive adhesive layer can be reduced (see Patent Literature 1 listed below).

Patent Literature 1: Japanese Patent Application Laid-Open (JP-A) No. 2004-167673

The processes of piling several punched sheet-shaped products and packing the resulting pile require a high-cleanliness working environment such that dust, soil and so on can be prevented. In order to prevent scratches, cracks and so on during transportation, the packing material is carefully selected, and the packing process is also carefully performed.

On the other hand, panel makers use the carefully packed sheet-shaped products for assembling. However, unpacking of the carefully packed products is laboring and must be carefully conducted so as not to cause scratches or cracks, which is a significant work load.

After the unpacking, dust or soil must be cleaned from each individual sheet-shaped product, which is a complicated task.

The punched sheet-shaped product with a scratch or crack formed during the process of packing, transferring or unpacking is determined as a defective product. Therefore, there has been demanded for a solution to the problem of a reduction in the product yield or high cost, which is caused by a relatively large number of processes or a complicated process. Since optical displays as final products vary widely in terms of type and size, a wide variety of sheet-shaped products are produced by cutting and punching. For example, if there are 50 types of optical displays, individual makers should manufacture, stock and manage 50 types of sheet-shaped products corresponding thereto. However, properly stocking and managing all types of sheet-shaped products is a very complicated task, and inventory control under proper conditions requires an adequate warehouse space (in a clean room environment).

The invention has been made under the circumstances described above, and it is an object of the invention to provide a system and a method for manufacturing an optical display which allow an improvement in the yield of optical film components, a reduction in cost and an improvement in inventory control.

As a result of investigations for solving the problems, the invention described below has been completed.

The invention is directed to an optical display manufacturing system, including: feeding means that feeds a belt and sheet-shaped product including an optical film as a component of the optical display from a roll of the belt and sheet-shaped product; detection means that detects a defect of the belt and sheet-shaped product fed by the feeding means; cutting means that cuts the belt and sheet-shaped product into individual sheet-shaped products based on a result of the detection by the detection means; transfer means that transports each of the sheet-shaped products from the cutting means to a sticking process; and sticking means that sticks the sheet-shaped product transported by the transfer means to an optical display unit as another component of the optical display, wherein all of the means are placed on a continuous manufacturing line.

The effects of the invention are described below. The optical display includes at least the optical film and the optical display unit. The belt and sheet-shaped product includes at least an optical film layer and optionally, for example, a protective film layer. The belt and sheet-shaped product is long and provided in the form of a roll. The belt and sheet-shaped product is fed from the roll, when whether or not defects such as stains, scratches and cracks are present is detected by the detection means.

According to the result of the detection, the belt and sheet-shaped product is cut into specific size pieces. The “specific size” depends on the size of the optical display product. When a certain defect is found as a result of the detection, for example, the cutting means is controlled such that the defect can be removed while specific size cut pieces can be produced. The sheet-shaped product obtained by cutting is then transferred to a sticking process. The transferred sheet-shaped product is stuck to the optical display unit by the sticking means. All of these means are placed on a continuous manufacturing line.

In the above manufacturing system, desired size pieces can be directly obtained by cutting from the belt and sheet-shaped product having the optical film and each stuck to the optical display unit. Therefore, a roll of the belt and sheet-shaped product can be directly packed and delivered to panel makers in contrast to the conventional technique where the belt and sheet-shaped product is subjected to punching, and punched sheet-shaped products are carefully packed and supplied to panel makers. Packing the roll allows easy selection of the packing material, allows simple packing operation with no need of a conventional packing tool or instrument for piling and packing sheet-shaped cut products and allows a reduction in the work load. There is also no need to perform the conventional end face working, which is also significantly advantageous for optical film component makers because of a reduction in the number of working processes.

Panel makers to which the products are supplied can easily perform the unpacking so that the work load can be reduced. Transferring the roll can also reduce the occurrence of scratches, cracks and so on and can prevent quality degradation.

In addition, the packing material can be simple, and the packing material cost and the occurrence of scratches, cracks and so on during the transportation can be reduced, so that the cost performance of the whole of the product can be significantly increased. It is also unnecessary for optical film component makers to cut sheet-shaped products depending on the type and size of the final optical display product or to stock and manage individual sheet-shaped products. The belt and sheet-shaped product itself (in the form of a raw roll) can be stored and managed so that inventory control can be simplified and that control management can be significantly improved. This is also advantageous for panel makers, because it is possible to stock and manage only a single type or few types of row rolls of the belt and sheet-shaped product and to cut a necessary portion (size) in a necessary form for use in manufacture so that expensive optical film stocks can be significantly reduced. According to the invention, therefore, both makers can significantly increase the productivity.

In a preferred embodiment of the invention, the belt and sheet-shaped product has a pressure-sensitive adhesive for sticking to the optical display unit and a release film for protecting the pressure-sensitive adhesive, and the system further includes separating means that separates the release film from the belt and sheet-shaped product before the detection of a defect by the detection means and cleaning means that cleans the belt and sheet-shaped product from which the release film has been separated, before the detection of a defect by the detection means.

In this embodiment, the belt and sheet-shaped product further includes a pressure-sensitive adhesive for sticking the optical display unit and a release film for protecting the pressure-sensitive adhesive. Before a defect is detected by the detection means, the release film is separated from the belt and sheet-shaped product, and the resulting belt and sheet-shaped product is cleaned by the cleaning means so that dust and soil can be removed. According to these features, the detection means can precisely detect scratches, cracks, stains and so on of the optical film component, while scratches, stains and so on of the release film are not detected.