OPTICAL ELEMENT, OPTICAL LENS, OPTICAL HEAD DEVICE, OPTICAL INFORMATION DEVICE, COMPUTER, OPTICAL INFORMATION MEDIUM PLAYER, CAR NAVIGATION SYSTEM, OPTICAL INFORMATION MEDIUM RECORDER, AND OPTICAL INFORMATION MEDIUM SERVER

摘要

PROBLEM TO BE SOLVED: To provide an optical element, an optical lens, and a device and a system employing these in which variation of focal distance and occurrence of spherical aberration are suppressed and reproduction and recording of information are stable at the time of variation in the wavelength such as switching of light quantity.

SOLUTION: An optical lens is provided with a hologram 134, a refraction type lens 144, and phase level difference 1442. The hologram 134 comprises a sawtooth type lattice of a sawtooth cross section type. In the hologram 134, +2 order diffraction light is generated most strongly for blue light by setting of depth of the sawtooth type lattice, +1 order diffraction light is generated most strongly for red light. The +2 order diffraction light of blue light is converged through a base material 9 having thickness t1, the +1 order diffraction light of red light is converged through a base material 10 having thickness t2, t1COPYRIGHT: (C)2004,JPO&NCIPI