| 摘要 |
A method for marking a key top made of a translucent material with a character, a symbol, or the like, with sufficient wear resistance at a timing free from restriction from other processes, and a process for producing an illumination key unit which can be completed in an extremely short time by determining a destination. Inside of a transparent plastic key top is irradiated intermittently with focused laser light having a wavelength belonging to near infrared region of 1064 nm or less, visible region or near ultraviolet region to form an aggregation of multiple fine carbonization black points and an aggregation of points whitened by fine cracks or bubbling representing a character, a symbol, or the like. Under a state where a process capable of being carried out without determining a destination has ended, production is interrupted temporarily or ended and marking is performed by irradiating the top surface of the key top with laser light upon determination of a character, a symbol, or the like, related with the destination. |
