| 摘要 |
<p>There is provided illuminating apparatus including an illuminating channel (10) defined between an incident surface (11), an emergent surface (12), an upper surface (13) and a lower surface (14). The upper surface (13) includes end portions (15) which may be adhered to the lower end portions (16) of an adjacent illuminating channel. The portion of the upper surface (13) between the end portions (15) comprises a steeply inclined outer portion (17), a horizontal central portion (20) and a shallow inner inclined portion (21). Light entering the incident face (31) at a low angle of incidence is reflected by total internal reflection in turn from the lower outer surface (32) of a first cavity (33), the central portion of the upper surface (34) of a second cavity (35), and then the inner lower surface (36) of the first cavity (33) before emerging from the emergent face (37). Light entering the incident face (31) at a medium angle of incidence is refracted at the incident face to a lower angle of refraction such that most incident light is reflected from locations distributed along the upper surface (40) of the cavity (41). Light entering the incident face (31) at a high angle of incidence is refracted to a lower angle such that most incident light falls on the outer end of the upper surface (42) of the cavity (43), such that the light rays are deflected through an angle sufficient for them to emerge from the emergent face (37) diffused and approximately perpendicular to the latter.</p> |
