| 摘要 |
PURPOSE:To reduce the size and weight of a light emitting device by using a light transmission member having a function for correcting a light from a light source to parallel beam and an ellipse correcting function. CONSTITUTION:The second surface (plane of emission) 3b of a light transmission member 3 is brought in coincidence with the end 5a of an opening side, and a first surface (plane of incidence) 3a is disposed in a housing 5. Electrodes 6 are energized to emit a light beam L1 from a light source 12 toward a light transmission member 3. The beam L1 is refracted at the first surface ea of the member 3, corrected to a parallel beam (light beam L2) to the second surface 3b. lt is elliptically corrected by the second surface 3b to an emitted light beam L3 in which its perpendicular section is circular and its optical axis coincides with the axial direction of the housing 5. The beam L3 is applied as a spot S on a recording film 33 opposed to a guide groove 34, and the reflected light is introduced through the film 33 and a disk substrate 32 to an objective lens 22 side. |
