| 摘要 |
PURPOSE:To make it unnecessary to adjust a position at assembling the titled device into an applied apparatus, and to make it small in size and simple by using a beam reflected by a triangular prism which has been fixed onto a photodetector, as an irradiating beam, and detecting a transmitting beam. CONSTITUTION:A beam 4 which is emitted from a laser diode chip 31 and is reflected by a slant face 27a of a triangular prism 27 transmits through a window glass 32 and an objective lens 5 and is made incident on an optical recording medium 6. On the other hand, the beam 4 which is reflected by the medium 6 is made incident on the slant face 27a, in a converging state, and made incident on a PIN diode 25 and detected, in a state that an astigmatism is generated by a difference of a refractive index between the prism 27 and air. In this way, when incorporating the titled device into an applied apparatus, it is made unnecessary to adjust a position between each parts, and it can be made small in size and simple. |
