| 摘要 |
PURPOSE:To make a device light and small and lower cost by constituting a collimator lens and an objective lens by combining plane-convex lenses and holograms that correct their aberration. CONSTITUTION:A collimator lens and an objective lens are constituted by combining plane-convex lenses 12, 17 and holograms 13, 16 having the function of correcting their aberration. In this case, a beam is converged by plane-convex lenses 12, 17, and aberration generated by the beam convergence is corrected by holograms 13, 16. Only the function of correcting aberration of plane-convex lenses 12, 17 is given to holograms 13, 16, and the function of converging the beam is not given, and accordingly, holograms 13, 16 become near the shape of a plane grating. Such holograms 13, 16 can be made with two luminous fluxes being plane wave or nearly parallel light, easily and high in efficiency. On the other hand, since plane-convex lenses 12, 17 are of transmission type, they are high in efficiency and suitable for mass production with low cost. |
