Directional light-shield board

摘要

Disclosed is a light-shield board for placement in front of a visual display device such as a cathode-ray tube in a television set or an information system. The light-shield board comprises a transparent substrate and an opaque film which is bonded to the substrate and is formed with a number of substantially uniformly distributed light-transmitting apertures, which may be rectangular apertures arranged in a checkered pattern. So, the opaque film comprises wall-like parts respectively partitioning the apertures. The apertures are bored obliquely such that at least a selected portion of the wall-like parts of the film are unidirectionally inclined from a plane normal to the film. Besides the function of restricting the angle of incidence of extraneous light on the display screen, this light-shield board serves the purpose of controlling the angles of diffusion of light from the display screen and hence enabling to sight the display screen from limited directions only. For example, by applying this light-shield board to a car television set in the instrument panel it is possible to disenable the driver to sight the television screen while a passenger in the front seat next to the driver can sight the screen.