OBJECTIVE LENS, OPTICAL HEAD, OPTICAL DISK DEVICE, AND INFORMATION PROCESSING DEVICE

• Main Authors: SHIROIWA HIROSHI, YAMASAKI FUMITOMO, ASADA JUNICHI, KOMMA YOSHIAKI, KAJINO OSAMU, TERAHARA NORIAKI, TANAKA TOSHIYASU
• Format: Patent
• Language: English
• Published: 14.03.2013
• Subjects: INFORMATION STORAGE; INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORDCARRIER AND TRANSDUCER; OPTICAL ELEMENTS, SYSTEMS, OR APPARATUS; OPTICS; PHYSICS

A disclosed objective lens includes: a lens having an entrance surface and an emission surface; and an anti-reflection coat formed on the emission surface, wherein a transmittance T1-0 [%] of the anti-reflection coat when an incident angle of a first laser beam having a first wavelength λ1 (390 nm λ1 430 nm) is 0°, and the transmittance T1-40 [%] of the anti-reflection coat when the incident angle of the first laser beam is 40° satisfy 0.95 T1-0/T1-40 1.05, and a transmittance T2-0 [%] of the anti-reflection coat when an incident angle of a second laser beam having a second wavelength λ2 (630 nm λ2 680 nm) is 0° and a transmittance T2-40 [%] of the anti-reflection coat when the incident angle of the second laser beam is 40° satisfy 0.85 T2-0/T2-40 0.97.