| 摘要 |
PURPOSE:To remove aberrations by a simple aberration correcting optical system and to reduce the size, weight and cost of a device by forming a focusing diffraction grating to the shape at which the exit angle of the light beam emitting from central position of the arraying direction of the grid attains nearly 0 deg.. CONSTITUTION:The focusing diffraction grating to be formed on the surface of a light guide is formed to the shape at which the exit angle of the light beam emitting from the central position in the arraying direction of the grating attains nearly 0 deg.. The aberration nearly the same as the aberration in the case of condensing the light beam by an ordinary single spherical lens is generated in the case of emitting the guided light 13 to the outside of the focusing diffraction 11 from the focusing diffraction grating at such angle. The aberration is, therefore, removed by passing the light beam emitted from the light guide element 10 through the correcting optical system consisting of the spherical lens. This correcting optical system is easily constituted from, for example, a concave lens 30 and a convex lens 31. |
