Characteristic of a Plastic Film Thickness Measuring System Using a Slit Beam X-ray

Abstract

The employment of plastic films has increased rapidly with use in flat-panel displays, secondary cells, and electronic devices, in order to make such devices lighter, thinner, and denser. Conventionally, the X-ray thickness measuring system for plastic films usually employs an X-ray spot beam of 10-20mm in diameter. However, this beam area is too large to measure some films, such as small size film components used in electronic devices. Therefore, it is necessary to improve the resolution ability. In the present study for solving this problem, the authors describe a new measuring system using a slit beam X-ray of 0.4mm to accurately measure the thickness of plastic films. The use of this system can drastically improve the resolution in the measurement of plastic film thickness, resulting in an accuracy of ±2.7% or less, for the sample film by the superposition of a polypropylene tape (PP, thickness: 30μm, width: 1or 20mm) over a PP film (thickness: 30μm).