| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a wavelength plate functioning as a quarter wave plate over a wide band of 400 to 780 nm to be a wavelength band required for an optical pickup corresponding to not only optical disks of a CD and DVD but also a blue laser disk. <P>SOLUTION: The wavelength plate 4 is formed by laminating a first wavelength plate 5, a second wavelength plate 6 and a third wavelength plate 7 at prescribed in-plane azimuthal angles, and as substrate materials of the wavelength plates, a quartz crystal is used for the first and the second wavelength plates 5 and 6, and lithium niobate is used for the third wavelength plate 7. The first wavelength plate 5 has a phase difference Γ1=180 deg. (λ=600 nm) and an in-plane azimuthal angle θ1=11.5 deg., the second wavelength plate 6 has a phase difference Γ2=195 deg. (λ=600 nm) and an in-plane azimuthal angle θ2=56.1 deg. and the third wavelength plate 7 has a phase difference Γ3=103 deg. (λ600 nm) and an in-plane azimuthal angle θ3=-45.0 deg. as each parameter of the wavelength plate 4. <P>COPYRIGHT: (C)2006,JPO&NCIPI |
