| 摘要 |
PURPOSE: An optical pickup is provided to convert a laser beam into a parallel beam, and to use an aspherical total reflection mirror or prism for reflecting the beam toward a recording surface of an optical disk, thereby simplifying a configuration without using a collimator lens. CONSTITUTION: A laser diode emits a laser beam. An aspherical total reflection mirror or prism(32) converts the emitted laser beam a parallel beam, and totally reflects the parallel laser beam at 90-degree angle. A half mirror transmits the totally reflected beam by 50 percent. An objective lens condenses the parallel laser beam passing through the half mirror, forms a beam spot on a recording layer(21) of an optical disk(20), and converts a beam reflected by the recording layer(21) into a parallel beam, and transmits the parallel beam. The half mirror reflects the converted reflected beam at 90-degree angle. A condensing lens condenses the reflected beam into a photo diode. The photo diode converts the reflected beam into an electrical signal to output the electrical signal. |
