| 摘要 |
An optical pickup device including a dual wavelength light source module for emitting a selected one of two light beams having different wavelengths, a dual grating for splitting, into three beams, the selected light beam emitted from the dual wavelength light source, and a hologram for focusing the three beams of the selected light beam onto a photodetector having typical 8-section patterns such that the three beams of the selected light beam are focused onto the same spots as those of the other light beam, respectively.
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