| 摘要 |
<p>A silicon substrate is disposed parallel with an optical disc. A prism for transmitting an incident beam is installed on the silicon substrate. A diffraction grating on a side surface of the prism. A beam splitter for partially reflecting and partially transmitting the laser beam is positioned inside of the prism to be slanted. The beam irradiated from the laser light source is reflected by the beam splitter after having transmitted through the diffraction grating. The reflected beam focuses onto the optical disc via a selective light-transmitting part formed on the upper surface of the prism. The beam is totally transmitted through an inner circular portion of the selective light-transmitting part and half transmitted through a peripheral portion of the selective light-transmitting part. The beam reflected from the optical disc partially is transmitted through the beam splitter, and then reflected a reflecting layer formed on the lower surface of the prism, and received a photodetector formed on an upper surface of the prism.</p> |
