| 摘要 |
PROBLEM TO BE SOLVED: To make possible obtaining an effect similar to that a numerical aperture of an objective lens is increased without revising the objective lens of an optical pickup device by providing a refractive angle control layer on a surface part of a transparent substrate. SOLUTION: This optical recording medium is provided with the substrate 1 consisting of transparent material and a signal recording layer 2 formed on the rear surface part of the substrate 1. The substrate 1 is provided with a hologram lens 3 as the refractive angle control layer controlling a refractive angle of light made incident from the surface part into the substrate 1 on the surface part. The hologram lens 3 performs the control that when θA≠0, nA.sinθA<nB.sinθB holds, and performs the control that when θA-0, 0<=θB holds when the refractive index of the material of the external side of the substrate 1 is defined nA, the refractive index of the substrate is nB, the incident angle of the light for the substrate 1 is θA and the refractive angle of the light after the light is made incident on the substrate 1 is θB. |
