摘要:
There is provided a program reservation recording device capable of reducing load on a server and performing program recording as is reserved by a user. Immediately before the reserved program is started and immediately before the end of it (S1), the program reservation recording device makes a request to an information providing server connected via a general-purpose network so as to acquire the latest program list (S2). The program reservation recording device compares the reservation information indicating the program reservation contents (start time, end time, etc.) to be stored in a memory with the latest program list acquired (S3). If any mismatch is present, the reservation information is updated according to the program list (S4).
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 optical head device includes a light source for emitting light; an optical system for focusing the light emitted by the light source onto an information medium to form a light spot; a photodetector including a plurality of light detection areas for receiving the light reflected by the information medium and for outputting photocurrents in accordance with the respective amount of the light received; a holographic optical element for diffracting the light reflected by the information medium and for directing the light to the photodetector; and a signal processing circuit section for obtaining a focusing error signal and a tracking error signal for controlling the light spot using the photocurrents. The signal processing circuit section obtains the focusing error signal from the photocurrents which are obtained in accordance with the amount of light of one of .+-.Nth-order diffracted beams, and obtains the tracking error signal from the photocurrents which are obtained in accordance with the amount of light of the other of the .+-.Nth-order diffracted beams.
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:
In a photodetector, the minimum size of the photodetection area for detecting a focus error signal from a light beam on the inner radius side of a hologram is made smaller than the minimum diameter of diffracted light beam spots (30, 31) for recording and reproduction, and when a CD is reproduced, a light beam close to the optical axis is made to significantly contribute to the focus error signal and the minimum size of the photodetection area for detecting the focus error signal from a light beam from the peripheral side of the hologram is made larger than the minimum diameter of diffracted light beam spots (130, 131) for recording and reproduction, whereby the focus error signal is made equal to the normal focus error signal when a DVD is reproduced, so that the focus offset variation caused when the base material thickness varies can be reduced.
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 is obtained on the basis of the diffracted light beam of +1st order and a tracking error signal is obtained on the basis of the diffracted light beam of -1st order.
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.