LIGHTING DEVICE, PROJECTION DEVICE, AND PROJECTION TYPE VIDEO DISPLAY DEVICE

摘要

PROBLEM TO BE SOLVED: To provide a lighting device capable of obscuring speckles.

SOLUTION: A lighting device 40 comprises: an optical element 50 including a hologram recording medium 55 capable of reproducing an image of a scattering plate; and an illumination device 60 which emits coherent light to the optical element such that the light scans on the hologram recording medium. Coherent lights entered from the illumination device onto respective locations of the hologram recording medium are superimposed on an illumination object region respectively to reproduce an image 5. A region IA on the hologram recording medium that is illuminated with the coherent light at an arbitrary instance has an area larger than a cross section of the coherent light immediately after emitted from the light source of the illumination device.

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