ILLUMINATION DEVICE USING COHERENT LIGHT SOURCE

摘要

A laser beam (L50) generated by a laser light source (50) is reflected by a light beam scanning device (60), and irradiated onto a hologram recording medium (45). On the hologram recording medium (45), an image (35) of a scatter plate is recorded as a hologram by using reference light that converges on a scanning origin (B). The light beam scanning device (60) bends the laser beam (L50) at the scanning origin (B) and irradiates it onto the hologram recording medium (45). At this time, scanning is carried out by changing the bending mode of the laser beam with time so that the irradiation position of the bent laser beam (L60) on the hologram recording medium (45) changes with time. Regardless of the beam irradiation position, diffracted light (L45) from the hologram recording medium (45) reproduces the same reproduction image (35) of the scatter plate at the same position. An illumination spot in which speckles are reduced is formed on the light receiving surface (R) of an illuminating object (70) by the reproduction image (35) of the hologram.