Nonreflective and limitatively light-transmitting board

摘要

A board suitable for use as a front cover of a vehicle instrument panel. The board consists of a transparent plate and an opaque shade film which is bonded to a major surface of the transparent plate and is formed with a number of substantially uniformly distributed light-transmitting holes. To adequately limit diffusion of light transmitted from the shade film side, the holes are designed such that the ratio of the hole diameter to the hole depth, i.e. shade film thickness, is greater than 0.23 and smaller than 0.5 and that the ratio of the hole diameter to the distance of each hole form every adjacent hole is greater than 1.2 and smaller than 25. The exposed front surface of the transparent plate is finished to a surface roughness of 0.15-0.40 micron so as to become a difusely reflective surface to thereby prevent undesirable reflection of extraneous light such as sunlight from this surface. The holed shade film is usually formed by using a photosensitive resin and is preferably matte-finished at least in its inner surfaces defining the respective light-transmitting holes.