| 摘要 |
<p>Focusing detector (1) comprises a laser diode (31), a prism (37), and photodiodes (33-36), mounted on a Si substrate (32). Light omitted from the laser (45) illuminates an object and is reflected back into a half-mirror plane (37a) of the prism (37). Optics are arranged so that the convergence point is formed on the top plane (37c) when focusing is achieved. Two photodetectors (33,34), each of which consists of three diodes, are used to compare the beam spot size on the bottom (37b) and to detect this condition. Other photodetectors (35,36) are used for tracking and laser power monitoring purposes, respectively.</p> |
