Patent ID: 7848185
Filing Date: 2010-12-07
Classification: G11B

Abstract:
1. An optical pickup, comprising: a blue laser source; at least either one of a red laser source and an infrared laser source; a blue light objective lens focusing blue light emitted from the blue laser source onto an optical storage medium; a red and infrared light objective lens focusing red light emitted from the red laser source and infrared light emitted from the infrared laser source onto the optical storage medium; optical path branching unit separating the blue light from the red and infrared light, the optical path branching unit being provided along optical paths extending from the blue laser source, the red laser source, and the infrared laser source to the blue light objective lens and the red and infrared light objective lens; and blue light decay unit decaying the blue light, the blue light decay unit being provided along an optical branch path extending from the optical path branching unit to the red and infrared light objective lens, wherein the blue light decay unit contains at least either a low blue light transmittance plane transmitting the red and infrared light and having a lower transmittance for the blue light than a reflectance for the blue light or a low blue light reflectance plane reflecting the red and infrared light and having a lower reflectance for the blue light than a transmittance for the blue light, and the low blue light transmittance plane has a transmittance of not more than 30% for blue light at wavelengths of from 390 nm to 420 nm, inclusive and the low blue light reflectance plane has a reflectance of not more than 30% for blue light at wavelengths of from 390 nm to 420 nm, inclusive.