Polarizer slitting method

Abstract

Regarding polarizers in which a dichroic dye is adsorbed and oriented on a polyvinyl alcohol-based resin film, the method for suppressing tearing of the polarizer when cutting the edges in the width direction of the polarizer is important. [Solution] The polarizer slitting method involves cutting the end of the polarizer 40 in the width direction parallel to the transport direction D1 of the polarizer 40. The polarizer slitting method includes an insertion step of inserting the blade tool 27 of an ultrasonic cutter into the inside of the polarizer 40 from the end 41 of the polarizer 40 in the width direction. The insertion step is a step of moving the blade tool 27 toward the inside of the polarizer 40 in the width direction while maintaining the angle of the blade tool 27 when inserting the blade tool 27 from the end 41 of the polarizer 40. In the insertion step, the angle of the blade tool 27 is maintained so that the angle A1 between the direction of movement D21 of the blade tool 27 and the direction D3 in which the blade tip is facing is 50° or more and 65° or less, and the movement speed of the blade tool is 80 mm / sec or less.

Claims

1. A polarizer slitting method for a polarizer being transported by a film transport device that transports polarizers in which a dichroic dye is adsorbed and oriented on a polyvinyl alcohol-based resin film, wherein the end of the polarizer in the width direction is cut parallel to the transport direction of the polarizer, The process of inserting the cutting tool of the ultrasonic cutter into the inside of the polarizer from the edge of the polarizer in the width direction, The process includes a straight-line step of holding the cutting edge of the cutting tool, which is placed inside the polarizer, in a state where it is facing upstream of the polarizer in the transport direction, The aforementioned entry step is a step in which, when inserting the cutting tool from the edge of the polarizer, the cutting tool is moved toward the inside of the polarizer in the width direction while maintaining the angle of the cutting tool, In the entry process, the angle of the cutting tool is maintained such that the angle between the direction of movement of the cutting tool and the direction in which the cutting edge is facing is between 50° and 65°, and the movement speed of the cutting tool is set to 80 mm / sec or less. Method for slitting polarizers.

2. The process includes an angle-changing step of moving the cutting tool toward the inside of the polarizer in the width direction while gradually changing the angle of the cutting tool placed inside the polarizer, The entry step, the angle change step, and the straight-line step are performed in order. In the angle changing step, the angle between the direction of movement of the cutting tool and the direction in which the cutting edge is facing is changed from the angle of the cutting tool at the start of the angle changing step to 90°. In the angle changing step, for each 1° change in the angle of the cutting tool, the movement speed of the cutting tool is reduced by a decrease of 1.5 mm / sec or less. The polarizer slitting method according to claim 1.

3. The vibration frequency of the cutting tool is set to between 20 kHz and 40 kHz. The polarizer slitting method according to claim 1 or 2.

4. The transport speed of the polarizer is 10 m / min or more and 50 m / min or less. The polarizer slitting method according to claim 1 or 2.

5. This includes a step of removing the cutting tool from the polarizer, The aforementioned removal step is a step of removing the cutting tool from the polarizer while maintaining the angle of the cutting tool and moving the cutting tool toward the edge of the polarizer in the width direction, In the exit step, the angle of the cutting tool is maintained such that the angle between the direction of movement of the cutting tool and the direction in which the cutting edge is facing is between 50° and 65°. The polarizer slitting method according to claim 1 or 2.

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