| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide an optical information reproduction apparatus for detecting an interference type optical information signal, which facilitates an adjustment of an optical path difference of two light beams and has a high signal amplification effect. <P>SOLUTION: An optical information recording/reproduction apparatus divides a luminous flux emitted from a light source 101 into a first luminous flux 102 as signal light, and a second luminous flux 103 as reference light which does not condense onto a light information recording medium, and performs a detection by causing the signal light and the reference light to optically interfere with a phase relationship therebetween being different from each other. The first or second luminous flux is defocused to the front/back by a first lens 113 and a second lens 114 so as to acquire a focus error signal from a difference signal thereof. <P>COPYRIGHT: (C)2013,JPO&INPIT |
