Abstract: In a preferred embodiment, an optical rotation sensor for a rotating member, the optical rotation sensor including: at least one reflective element disposed on the surface of the rotating member; first light transmission means to transmit light from a light source, disposed at the proximal end of the first light transmission means remote from the rotating member, to illuminate the surface of the rotating member at the distal end of the first light transmission means; and second light transmission means to transmit from the distal end of the second light transmission means to a first photodetector, disposed at the proximal end of the second light transmission means remote from the rotating member, light reflected from the at least one reflective element as the at least one reflective element passes the distal end of the second light transmission means as the rotating member rotates.

Abstract: Improvements in alternating current plasma display panels are disclosed including an imperforate intermediate structure in such a panel which provides both the function of a separator between the front and back plates (layers or structures) of the panel and the function of cross talk reducing barriers between cells of the panel. The structure includes spacing bosses which extend from the barrier structure and engage the front transparent dielectric plate, and sidewall portions intermediate adjacent pairs of spacing bosses which are separated somewhat from the front dielectric plate to provide a gas and ion passing gap between adjacent cells. In one preferred form, the sidewalls blend into a generally flat bottom wall within each cell. The sidewalls and bottom wall have a smooth or specular surface and may be coated with a reflective material to enhance cell brightness.