| 摘要 |
PURPOSE:To greatly reduce the loss of incident rays and at the same time to obtain the desired diffused light, by forming a transmission type screen provided with a number of optical fibers close to the direction of the end face of said screen. CONSTITUTION:An optical fiber 2 composed of columnar acrylic fibers is formed into a desired length. A number of such fibers 2 are gathered together so as to arrange their end faces at the same level, and the outer circumference walls are adhered to each other by means of an adhesive of epoxy resin, etc. Thus a screen 1 is obtained. In this case, the black color is desirable for the adhesive 4 in order to ensure a higher contrast for the screen 1. For instance, incident rays 7a, 7b and 7c are made incident through an end face of the fiber 2 and propagate with different points of reflection to be turned into diffused rays 7a', 7b' and 7c' respectively when they are radiated through the other end face. The incident rays 7 almost passes through the fiber 2, and at the same time the diffused rays are obtained. Thus no loss caused on the diffusing surface unlike the conventional case. The loss is reduced to <=5% by keeping the thickness of the screen 1 to <=10cm. |
