CONTACT DETECTING DEVICE, APPARATUS USING THE DEVICE AND RADIO TELEPHONE SET INCLUDING THE APPARATUS

摘要

PROBLEM TO BE SOLVED: To provide a means for realizing a contact detecting device including an integrated illumination system and having small thickness and weight and a low manufacturing cost. SOLUTION: A system for detecting the operation of each key of a keyboard and a uniform illumination system of the keyboard are integrated on the synthetic material foil of a device. A film 10 is folded into two portions 11, 12, a dome section 13 is preliminarily molded on the upper portion 11, and a detecting circuit 16 is printed on the lower portion 12. A contact electrode 15 is fixed beneath each dome section 13 to realize an electric contact with the detecting circuit 16 when the dome section 13 is depressed by a key of the keyboard. The key of the keyboard is illuminated by an electroluminescent ink 17 between the dome sections 13 arranged on the flat face 18 of the upper portion 11 of the synthetic material foil 10. This device can be applied to a portable electronic apparatus and a radio telephone set including the keyboard.