摘要:
An optical pickup head for performing recording, reproducing and erasing of information on an optical disc in an optical system employs an objective lens, which is integrated or combined with a holographic optical element, so that the focusing of a diffraction beam on a photo-sensor is stabilized irrespective of the movement of the objective lens due to the tracking control operation in the optical system.
摘要:
Disclosed is a compact optical pick-up head apparatus suitable for mass-production, which comprises a light radiation source, an element composed of photodetector split into a plurality of regions and integrated on the same base, an objective lens for focusing a beam from the above source on an optical disk, a blazed hologram integrated to the support member of the lens, a means for driving the support member to which the objective lens and blazed hologram are integrated in response to an output as servo signal output from the photodetector which receives a diffracted beam produced in such a manner that a return beam reflected or diffracted by the optical disk is incident on the objective lens integrated with the above hologram. The optical pickup apparatus according to the present invention employs a region-split-type phase hologram in which a pair of Flesnel zone plate-like patterns, by which a plurality of diffraction wavefronts having a different focus and the same diffraction order are produced outside an optical-axis, are non-superimposedly formed. The above hologram can be blazed with a pinpoint accuracy by lithography using a few mask patterns synthesized by a computer, and further a more preferably blazing can be realized by the combination of the ion beam etching and the lithography. Accordingly, not only noise caused by an unnecessary diffracted beam component but also the offset of a servo signal can be restrained and the size of the objective lens can be reduced by the integration of the entire optical system, which greatly contributes to the superminiaturization of an optical head.
摘要:
An optical head device includes: a light source for emitting a light beam; an objective lens for converging the light beam on an information storage medium; a hologram for receiving the light beam reflected by the information storage medium and generating diffracted light from the light beam, the hologram having such a polarization anisotropy that it diffracts light in a second polarization state more strongly than light in a first polarization state which is different from the second polarization state; and a photodetector including a plurality of photodetective sections for receiving a part of the diffracted light and outputting a photocurrent in accordance with the intensity of the part of the diffracted light. The optical head device further include a quarter-wave plate disposed between the objective lens and the hologram for causing the polarization state of the light beam reflected by the information storage medium to be the second polarization state; and the hologram is disposed so that the distance between the hologram and the objective lens is shorter than the distance between the hologram and the photodetector.
摘要:
The invention presents an optical element with which an optical head can be configured, in which there is little deterioration of the correctional effect when the objective lens shifts, as well as an optical head and an optical recording/reproducing apparatus using such an optical element. The invention also presents a novel optical recording/reproducing apparatus and optical recording/reproducing method. The optical element, includes a first voltage application electrode 13, a first opposing electrode 17 arranged in opposition to the first voltage application electrode 13, and a first phase changing layer 15 arranged between the first voltage application electrode 13 and the first opposing electrode 17. By changing a voltage between the first voltage application electrode 13 and the first opposing electrode 17, a phase that converts plane waves into spherical waves is imparted on light that is incident on the first phase changing layer 15.
摘要:
The invention presents an optical element with which an optical head can be configured, in which there is little deterioration of the correctional effect when the objective lens shifts, as well as an optical head and an optical recording/reproducing apparatus using such an optical element. The invention also presents a novel optical recording/reproducing apparatus and optical recording/reproducing method. The optical element, includes a first voltage application electrode 13, a first opposing electrode 17 arranged in opposition to the first voltage application electrode 13, and a first phase changing layer 15 arranged between the first voltage application electrode 13 and the first opposing electrode 17. By changing a voltage between the first voltage application electrode 13 and the first opposing electrode 17, a phase that converts plane waves into spherical waves is imparted on light that is incident on the first phase changing layer 15.
摘要:
An information recording/reproducing apparatus determines whether ejection of an optical disk stored in an optical disk drive or in a changer is allowed when receiving a command for ejecting the optical disk to the outside. The information recording/reproducing apparatus allows the optical disk to be ejected only when judging that the ejection is allowed. When judging that the ejection is not allowed, the information recording/reproducing apparatus rejects the ejection. Prohibition of ejection of an optical disk on which information whose copyright is to be protected has been recorded enables the use of the information for private hobby and at the same time prevents pirated versions or the like from being produced, thus realizing copyright protection.
摘要:
The invention presents an optical element with which an optical head can be configured, in which there is little deterioration of the correctional effect when the objective lens shifts, as well as an optical head and an optical recording/reproducing apparatus using such an optical element. The invention also presents a novel optical recording/reproducing apparatus and optical recording/reproducing method. The optical element, includes a first voltage application electrode 13, a first opposing electrode 17 arranged in opposition to the first voltage application electrode 13, and a first phase changing layer 15 arranged between the first voltage application electrode 13 and the first opposing electrode 17. By changing a voltage between the first voltage application electrode 13 and the first opposing electrode 17, a phase that converts plane waves into spherical waves is imparted on light that is incident on the first phase changing layer 15.
摘要:
The invention presents an optical element with which an optical head can be configured, in which there is little deterioration of the correctional effect when the objective lens shifts, as well as an optical head and an optical recording/reproducing apparatus using such an optical element. The invention also presents a novel optical recording/reproducing apparatus and optical recording/reproducing method. The optical element, includes a first voltage application electrode 13, a first opposing electrode 17 arranged in opposition to the first voltage application electrode 13, and a first phase changing layer 15 arranged between the first voltage application electrode 13 and the first opposing electrode 17. By changing a voltage between the first voltage application electrode 13 and the first opposing electrode 17, a phase that converts plane waves into spherical waves is imparted on light that is incident on the first phase changing layer 15.
摘要:
The invention presents an optical element with which an optical head can be configured, in which there is little deterioration of the correctional effect when the objective lens shifts, as well as an optical head and an optical recording/reproducing apparatus using such an optical element. The invention also presents a novel optical recording/reproducing apparatus and optical recording/reproducing method. The optical element, includes a first voltage application electrode 13, a first opposing electrode 17 arranged in opposition to the first voltage application electrode 13, and a first phase changing layer 15 arranged between the first voltage application electrode 13 and the first opposing electrode 17. By changing a voltage between the first voltage application electrode 13 and the first opposing electrode 17, a phase that converts plane waves into spherical waves is imparted on light that is incident on the first phase changing layer 15.
摘要:
A light beam emitted from a semiconductor laser element is collimated by a collimating lens, and is applied to an optical disk through a polarizing holographic beam splitter, a .lambda./4 plate and an objective lens, a light beam reflected by the optical disk is applied to the polarizing holographic beam splitter and is diffracted. Diffracted light beams of +1st order and -1st order are applied to two photodetectors, and a focus error signal and a tracking error signal are obtained on the basis of the diffracted light beam of +1st order and an information signal is obtained on the basis of the diffracted light beam of -1st order.