| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a wide-band wavelength plate receiving a plurality of light rays different in wavelength and emitting them by controlling the polarization state of the light rays, and to provide an optical head device. <P>SOLUTION: The wide-band wavelength plate 10 includes a first wavelength plate 11, a second wavelength plate 12 and a third wavelength plate 13 parallel to each other. The wavelength plate 10 emits light of wavelengths of λ<SB>1</SB>and λ<SB>2</SB>as circularly polarized light, and emits light of a wavelength of λ<SB>3</SB>as linearly polarized light (wherein λ<SB>1</SB><λ<SB>2</SB><λ<SB>3</SB>) to linearly polarized light of different wavelengths of λ<SB>1</SB>, λ<SB>2</SB>and λ<SB>3</SB>by adjusting retardation values Rd<SB>1</SB>, Rd<SB>2</SB>and Rd<SB>3</SB>of the three wavelength plates, and angles θ<SB>1</SB>, θ<SB>2</SB>and θ<SB>3</SB>formed by the vibration direction of incident light and each of the three wavelength plates. A compact optical head device and high-quality recording and playback can be achieved. <P>COPYRIGHT: (C)2010,JPO&INPIT |
