| 摘要 |
The device consists of a plate carrying a row of LED chips; and each chip is covered by a light dispersal element (i) extending to the surface of the plate. Element (I) consists of a casting contg. a colourless resin and a difuser, and possessing a convex shape. The resin is pref. an epoxy- or silicone- resin, whereas the diffuser is pref. alumina; and the casting pref. also contains a thixotropic agent, esp. pyrogenic silica. yThe thixotropic agent is pref. used to ensure that element (I) retains its shape while setting after casting. The unhardened resin mixt. pref. has a viscosity of 150-300 Pa.s. and contains 100 pts. wt. silicone resin, 4.5-7 pts. wt. silica, and 1-2 pts.wt. alumina; and this mixt. pref. contains a pigment absorbing external light. Similar conventional devices use tunnels round each chip, but these tunnels prevent the display from being seen clearly from viewing points not directly in front of the display. The invention eliminates this problem. |
