Film defect inspection device, defect inspection method, and release film

Abstract

Disclosed is a film defect inspection device for detecting defects in a long-length film, the inspection device including: an illumination means that is provided on the side of one surface of the film and that illuminates same; a first polarizing plate that is provided between the illumination means and the film; a second polarizing plate that is provided on the side of the other surface of the film; a light-receiving means that is provided on the side of the other surface of the film and that receives transmitted light which has been emitted from the illumination means and which has passed through the first polarizing plate, the film, and the second polarizing plate; and an angle adjustment means that separately adjusts the angle of the first polarizing plate within the plane thereof and the angle of the second polarizing plate within the plane thereof.

Description

technical field [0001] The present invention belongs to a defect inspection device for a polarizing plate release film that can perform simple and easy optical defect inspection of a film to be inspected, in particular, a defect inspection of a polarizing plate release film used in a polarizing plate manufacturing process before the polarizing plate is processed. and the technical field of defect inspection methods. Background technique [0002] In recent years, the demand for liquid crystal displays (LCDs), which have the advantages of thinner and lighter weight, lower power consumption, and higher image quality than conventional display CRTs, has rapidly expanded. In particular, large-screen monitors, such as large screens of 32 inches or more, LCDs for TV applications are developing rapidly. In many cases, with the increase of LCD screen size, by increasing the brightness of the backlight or adding a functional film that improves brightness, etc., an LCD that ensures suf...

AI Technical Summary

Problems solved by technology

As a result, there is a problem that defects existing in the film cannot be inspected with good precision at the center and end of the film depending on the position in the width direction during film production.

Therefore, in the case of inspecting a film having a birefringence deviation in the width direction, defect inspection cannot be performed with good accuracy at the same time

[0009] Furthermore, according to the knowledge of the inventors of the present invention, leaving aside defects that cause large changes in light intensity, in the case of defects that cause only small changes in light intensity, the field of view becomes darkest when inspected by cross-Nicols. When a polarizer is configured, the contrast difference is smaller and difficult to detect

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