Patent ID: 11953857
Assignee: DAI NIPPON PRINTING CO., LTD.
Field: Optics (Instruments)
Classification: CPC G  F  H | IPC F  G  H

Claim 0:
1. An illumination apparatus using a coherent light source, comprising:
a coherent light source (50) that generates a coherent light beam (L50);
a light beam scanning device (60, 65) that carries out beam scanning by controlling either or both of a direction and a position of the light beam (L50); and
an optical diffusing element (45, 46) that diffuses an incident light beam and emits a light beam, wherein, the optical diffusing element (45, 46) includes a hologram recording medium,
the light beam scanning device (60, 65) guides a light beam (L50) generated by the coherent light source (50) toward the hologram recording medium (45, 46), and carries out scanning so that an incidence position and an incidence direction of the guided light beam (L60) on the hologram recording medium (45, 46) changes with time, and
the hologram recording medium (45, 46) has a function of forming irradiation regions (I) on a light receiving surface (R) by diffusing an incident light beam, wherein the light receiving surface is not a refractive element, and is configured so that the formed irradiation regions (I) become substantially a same common region on the light receiving surface (R) regardless of an incidence position of the incident light beam, said irradiation regions (I) being irradiated by light which is diffused by said hologram recording medium and reaches said light receiving surface (R).