| 摘要 |
A first toroidal ray guide defines an axis of revolution and has a toroidal entrance pupil adapted to image light incident on the entrance pupil at an angle to the axis of revolution between 40 and 140 degrees, and it also has a first imaging surface opposite the entrance pupil. A second toroidal ray guide also defines the same axis of revolution and has a second imaging surface adjacent to the first imaging surface. Various additions and further qualities of the ray guides, which form optical channels, are disclosed. In a method light emanating from a source at between 40-140 degrees from an optical axis is received at an entrance pupil of a ray guide arrangement that is circularly symmetric about the optical axis. Then the received light is redirected through the ray guide arrangement to an exit pupil in an average direction substantially parallel to the optical axis. |
