| 摘要 |
<p>PURPOSE:To obtain an optical switch array type printing head having superior contrast characteristics by using an aperture type fluorescent lamp as a light source and making the longitudinal direction of the fluorescent lamp coincide with the polarizing shaft 10b of a polarizing plate or rectangular to the polarizing shaft 10b. CONSTITUTION:A light source 6 is arranged in parallel with a plastic rod lens and a polarizing plate 10b is arranged in the rectangular direction (Y-Y') to the longitudinal direction (X-X') of a rod lens. The spiral axis 8 of a liquid crystal part is set up to form an angle thetaa with the Y-Y' axis. In the constitution of a guest host type optical switch 3 having one polarizing plate, dichroic has coloring matter molecules 20 a property for absorbing light (polarized light) having the vibrating component in the long axis direction of a dichroic coloring matter molecules out of light made incident on the liquid crystal layer. If an electric field E is impressed when the diachronic coloring matter of black is mixed into the liquid crystal layer, the liquid crystal molecules are arrayed in the direction of the polarizing axis 10b. Since the dichronic coloring matter molecules 20 have the same array as the liquid crystal molecules 7, light made incident on the liquid crystal layer is absorbed by black and is not transmitted. Namely, the interrupted state of light is formed.</p> |
