摘要:
To read information from a target information recording surface reliably by canceling DC offsets in tracking-signal detection signals is provided. In effecting tracking servo by 3-beam method, auxiliary light receiving domains D3—1, D3—2, D8—1, D8—2 are provided. The auxiliary light receiving domain receives images formed by the light returned from a different information recording surface from the one targeted for reading. Sub beams of ± first-order diffracted light enter the light receiving domains D3, D8, D1, D10. With respect to the diffraction direction of the hologram, the auxiliary light receiving domains D3—1, D3—2 (D8—1, D8—2) are provided on both sides of the light receiving domain D3 (D8). Since signals are computed as: D8−(D8—1+D8—2); and D3−(D3—1+D3—2) with the internal connection, DC offsets can be canceled in RES signals (D1+D3, D8+D10) used in the DPP method.
摘要:
To read information from a target information recording surface reliably by canceling DC offsets in tracking-signal detection signals is provided. In effecting tracking servo by 3-beam method, auxiliary light receiving domains D3—1, D3—2, D8—1, D8—2 are provided. The auxiliary light receiving domain receives images formed by the light returned from a different information recording surface from the one targeted for reading. Sub beams of ± first-order diffracted light enter the light receiving domains D3, D8, D1, D10. With respect to the diffraction direction of the hologram, the auxiliary light receiving domains D3—1, D3—2 (D8 1, D8—2) are provided on both sides of the light receiving domain D3 (D8). Since signals are computed as: D8-(D8—1+D8—2); and D3-(D3—1+D3—2) with the internal connection, DC offsets can be canceled in RES signals (D1+D3, D8+D10) used in the DPP method.
摘要:
An object of the invention is to provide a splitter, a light emitter, and an optical pickup apparatus which can realize a stable track servo. Because of the structure of an optical system including an objective lens (27) and a hologram pattern (25), even when the hologram pattern (25) is irradiated with a reflected light from one recording layer other than another recording layer in a focused state, first and second TES splitting portions (35, 36) are not irradiated with the reflected light from the one recording layer, but the reflected light is led to an axis vicinity portion (38) only. Accordingly, light reception by first and second TES light receiving portions (45, 46) is prevented, accurate track position information and deviation information can be positively acquired, and troubles such as the objective lens (27) being driven beyond a movable range can be eliminated.
摘要:
An object of the invention is to provide a splitter, a light emitter, and an optical pickup apparatus which can realize a stable track servo. Because of the structure of an optical system including an objective lens (27) and a hologram pattern (25), even when the hologram pattern (25) is irradiated with a reflected light from one recording layer other than another recording layer in a focused state, first and second TES splitting portions (35, 36) are not irradiated with the reflected light from the one recording layer, but the reflected light is led to an axis vicinity portion (38) only. Accordingly, light reception by first and second TES light receiving portions (45, 46) is prevented, accurate track position information and deviation information can be positively acquired, and troubles such as the objective lens (27) being driven beyond a movable range can be eliminated.
摘要:
In this semiconductor laser device, a polarization hologram transmits an outgoing beam directed from a semiconductor laser chip to an optical disk as a forward beam without diffracting the beam, and diffracts a backward beam of the laser beam, which is a return beam of the forward beam that has been reflected by the optical disk, so that the backward beam is deflected from a direction directed toward the semiconductor laser chip part and further directed toward first, second photoreception parts. Therefore, optical loss on the forward way from the semiconductor laser chip to the optical disk can be reduced, and return light to the semiconductor laser chip can be suppressed, so that a high-power, high-sensitivity semiconductor laser device can be realized.
摘要:
A focus error detecting device which can realize stable focus servo without causing a deterioration in the quality of a signal, is provided. The focus error detecting device outputs a reflected light detection result by an optical recording medium to control a distance between an objective lens and the optical recording medium. With respect to the focus error detecting device, between the objective lens and two split light-receiving segments, is provided a hologram element for bending an optical path so that part of light reflected by the optical recording medium enters the two split light-receiving segments, and splitting a light beam of reflected light entering the two split light-receiving segments into a plurality of parts.
摘要:
Not only a semiconductor laser element and a photodetector but also a capacitor connected to the photodetector is housed in a package to thereby reduce the distance from the capacitor to the photodetector so that power source noise is efficiently suppressed by the capacitor and a power source noise suppression effect is improved.
摘要:
An optical pickup can be provided, the optical pickup being capable of recording and playback of a plurality of optical disks having different specs by using light beams of different wavelengths, and further being suitable for integrating the semiconductor lasers and light receiving elements into a single package, by including: first and second semiconductor lasers adjacently disposed; a three-beam diffraction grating for generating three beams for tracking control; a second hologram element for diffracting light of the second semiconductor laser to guide it to a photosensor; a complex polarization beam splitter (PBS) for reflecting only light from the first semiconductor laser; and a first hologram element for diffracting light of the first semiconductor laser to guide it to the photosensor.
摘要:
An optical pickup can be provided, the optical pickup being capable of recording and playback of a plurality of optical disks having different specs by using light beams of different wavelengths, and further being suitable for integrating the semiconductor lasers and light receiving elements into a single package, by including: first and second semiconductor lasers adjacently disposed; a three-beam diffraction grating for generating three beams for tracking control; a second hologram element for diffracting light of the second semiconductor laser to guide it to a photosensor; a complex polarization beam splitter (PBS) for reflecting only light from the first semiconductor laser; and a first hologram element for diffracting light of the first semiconductor laser to guide it to the photosensor.
摘要:
An optical pickup can be provided, the optical pickup being capable of recording and playback of a plurality of optical disks having different specs by using light beams of different wavelengths, and further being suitable for integrating the semiconductor lasers and light receiving elements into a single package, by including: first and second semiconductor lasers adjacently disposed; a three-beam diffraction grating for generating three beams for tracking control; a second hologram element for diffracting light of the second semiconductor laser to guide it to a photosensor; a complex polarization beam splitter (PBS) for reflecting only light from the first semiconductor laser; and a first hologram element for diffracting light of the first semiconductor laser to guide it to the photosensor.