| 摘要 |
PROBLEM TO BE SOLVED: To provide an optical pickup device by which a false error signal is not generated in a tracking error signal and to provide an optical recording and reproducing apparatus by which high-quality information can be recorded and reproduced. SOLUTION: A semiconductor laser is provided. A diffraction grating which separates a laser beam into zero-order light and±first-order light is provided. An objective lens which converges the zero-order light and the±first-order light is provided. A photodetector which comprises a first light receiving part 7a used to receive the zero-order light reflected and returned and which comprises a second light receiving part 7b and a third light receiving part 7c having two-split light receiving patterns used to receive the±first-order light is provided, A first computing means and a second computing means which sum-compute signals obtained by changing one output signal and the other output signal of the light receiving patterns used to receive the±first-order light to a prescribed multiple are provided. A third computing means which difference-computes output signals of the first and second computing means is provided. On the basis of an output signal from the third computing means, a tracking error signal is detected.
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