| 摘要 |
<p>Transparent material is injection molded to produce the first layer (37). This is cooled till the surface (39) is at least near the glass transition temperature and is then placed in a second mold with a larger cavity (14) into which further material is injected that joins homogeneously to complete the article. The transition temperature is preferably between 100 and 120 [deg]C. Independent claims are included for the following: (1) An injection tool to carry out this process and provide the two mold cavities; the two halves of the tool can be rotated relative to each other so that the bottom half (27) is used in both stages and different cavities are presented to form the top half; (2) A light guide comprising two homogeneous refraction-free layers made by this method, e.g. containing a lens (35) or prism section and a light guide (36) section. The tool can contain additional parts for molding more than two layers, optionally using different colors, and to allow for re-entrant features. It is fitted with temperature control arrangements, e.g. electric heaters.</p> |
