Plastic substrate thickness of 0.25mm and below is called film, which is mainly used as the panel layer of the film keyboard. Various indicative patterns and texts are printed on the back of the film to indicate the operation area of the corresponding switch key position. The thickness should be selected according to Depending on the size of the panel and buttons, the material is thick, the touch force is increased, and the response is slow; the material is too thin, the hand feel is poor when touched, and the rebound is not obvious. Thickness above 0.25mm is called a plate, which is not suitable for three-dimensional key forming. It can be used as an indicative sign panel for a keyless operation area, and can also be used as a lining board for a membrane keyboard to improve its hardness.
