Patent ID: 8081360

Claim:
A light-collecting device, comprising: a first volume hologram recorded in a hologram recording layer by interference of a first spherical wave and a planar wave, the first spherical wave passing through a light path of diffused light which radiates from a light incident point positioned on a back surface of the hologram recording layer, passes through the hologram recording layer and spreads to a predetermined diameter; and a second volume hologram recorded in the hologram recording layer by interference of a second spherical wave and the planar wave, the second spherical wave passing through a light path of converging light which radiates from the same side as the first spherical wave, passes through the hologram recording layer and converges at an image-forming point spaced apart from a front surface of the hologram recording layer by a predetermined distance, the planar wave intersecting with the first spherical wave and the second spherical wave in the hologram recording layer.