| 摘要 |
<P>PROBLEM TO BE SOLVED: To perform multi-value recording of light phase information using a device configuration simpler than a conventional one. <P>SOLUTION: In an information recording and reproduction device, a phase is recorded using a void 19 as a minute reflector. A laser pulse from a laser diode 13 is converted into parallel light by a collimator lens 14, and then focused by a lens 15. A refractive index modulator 16 is disposed in a space between the lens 15 and the focal point thereof. The laser light once focused changes into divergent light beyond the focal point, then is converted into parallel light by a lens 17, and finally is focused in a recording possible area 11 by an objective lens 18 with the result that a void 19 is formed. When the refractive index of the convergent light path is changed with the application of a voltage to the refractive index modulator 16, the position of the focal point of the lens 15 is shifted. In such a case, the light outgoing from the lens 17 ceases to be parallel light, turning into weakly convergent or divergent light. This causes the position of the focal point of the objective lens to shift, so that the record depth of the void 19 can be modulated. <P>COPYRIGHT: (C)2012,JPO&INPIT |
