Abstract:
A button includes a keycap made of transparent material and including a first side surface and a second side surface opposite to the first side surface, a light guide block set on the first side surface of the keycap, and an ultraviolet lighting element set on the first side surface to emit ultraviolet light. Ultraviolet light emitted by the ultraviolet lighting element may enter into the light guide block, then is reflected by the light guide block to pass through the keycap to arrive to the second side surface of the keycap.
Abstract:
An electron gun and a CRT capable of accomplishing a reduction in spot diameter of electron beams, an increase in drive speed and control of luminance while being simplified in structure. Field emission cathodes acting as the electron source for the electron gun are arranged in the form of or divided into plurality of the small regions S for matrix driving, to thereby control luminance of the CRT depending on the number of small regions S selected. Thus, luminance control over any desired number of gradations which exhibits satisfactory resistance to noise and linearity can be realized while simplifying the structure, resulting in the field emission cathodes being highly conveniently applied to the electron gun of the CRT, leading to an improvement in functionality of the CRT.