Abstract: A rewritable type optical disc includes recording tracks formed with break portions; and recording marks corresponding to predetermined data and formed on the recording tracks. The recording marks are formed over the break portions on the recording tracks. If the predetermined data, such as control data, recorded as the recording mark is illegally altered, the position of the recording marks are changed and some break portions are not covered by the recording marks. Since the return light level of the break portion, which is not covered by the recording mark, is different from the return light level of the break portion covered by the recording mark, such illegal alteration of the predetermined data such as the control data may be detected.

Abstract: An optical recording apparatus includes a light source driving unit for driving a light source; an emitted light power detecting unit for detecting an emitted light power; a temperature detecting unit for detecting a temperature of the light source; a light power control unit for adjusting a driving current of the light source such that a change rate of an emitted light power detection value fall within a predetermined range; and a detection value storing unit for storing a driving current adjustment value in association with a temperature detection value. The light power control unit adjusts the driving current value of the light source based on an stored detection value when the temperature detection value is within a range of temperature detection values already stored in the detection value storing unit.

Abstract: An information recording/reproducing apparatus which is capable of recording information data even if prepits cannot be correctly read from a recording medium. Prepits are detected from a read signal retrieved from a recording medium to generate a prepit detection signal, and a block signal indicative of a recording timing is generated based on the prepit detection signal. In this event, when the prepit detection signal is normal, an information signal is recorded on the recording medium at a recording timing in accordance with the block signal. On the other hand, when the prepit detection signal is defective, the information signal is recorded on the recording medium at a recording timing in accordance with an auxiliary block signal having the same period as a block length, and a fixed phase.

Abstract: A boundary position search method and an information recording apparatus are provided for rapidly transferring a recording/reproducing head to a boundary position between a recorded region and an unrecorded region of a recording disc when new information data is recorded on the recording disc. In response to a recording start instruction, the recording/reproducing head is first forcedly transferred in a radial direction of the disc, while confirmation is made as to the presence or absence of an RF signal carrying an information signal in a read signal. A slider unit is controlled to stop a transfer operation of the recording/reproducing head when a transition is detected from a state in which an RF signal exists to a state in which no RF signal exists.

Abstract: A boundary position search method and an information recording apparatus are provided for rapidly transferring a recording/reproducing head to a boundary position between a recorded region and an unrecorded region of a recording disc when new information data is recorded on the recording disc. In response to a recording start instruction, the recording/reproducing head is first forcedly transferred in a radial direction of the disc, while confirmation is made as to the presence or absence of an RF signal carrying an information signal in a read signal. A slider unit is controlled to stop a transfer operation of the recording/reproducing head when a transition is detected from a state in which an RF signal exists to a state in which no RF signal exists.

Abstract: An information recording/reproducing apparatus which is capable of recording information data even if prepits cannot be correctly read from a recording medium. Prepits are detected from a read signal retrieved from a recording medium to generate a prepit detection signal, and a block signal indicative of a recording timing is generated based on the prepit detection signal. In this event, when the prepit detection signal is normal, an information signal is recorded on the recording medium at a recording timing in accordance with the block signal. On the other hand, when the prepit detection signal is defective, the information signal is recorded on the recording medium at a recording timing in accordance with an auxiliary block signal having the same period as a block length, and a fixed phase.

Abstract: An optical recording apparatus includes a light source driving unit for driving a light source; an emitted light power detecting unit for detecting an emitted light power; a temperature detecting unit for detecting a temperature of the light source; a light power control unit for adjusting a driving current of the light source such that a change rate of an emitted light power detection value fall within a predetermined range; and a detection value storing unit for storing a driving current adjustment value in association with a temperature detection value. The light power control unit adjusts the driving current value of the light source based on an stored detection value when the temperature detection value is within a range of temperature detection values already stored in the detection value storing unit.

Abstract: A method for recording an information data signal on an optical recording medium includes the steps of identifying the position of a control data recording area where control data regarding recording of the information data signal is recorded; detecting a pre-pit signal by reading a predetermined section of the control data recording area; detecting an RF data signal by reading a predetermined section of the control data recording area; and executing either one of the step of detecting a pre-pit signal and the step of detecting an RF data signal to generate a recording synchronizing signal indicating recording start timing from the detected signal.

Abstract: A rewritable type optical disc includes recording tracks formed with break portions; and recording marks corresponding to predetermined data and formed on the recording tracks. The recording marks are formed over the break portions on the recording tracks. If the predetermined data, such as control data, recorded as the recording mark is illegally altered, the position of the recording marks are changed and some break portions are not covered by the recording marks. Since the return light level of the break portion, which is not covered by the recording mark, is different from the return light level of the break portion covered by the recording mark, such illegal alteration of the predetermined data such as the control data may be detected.

Abstract: A video disk recorder for executing a real-time edition records desired scenes to a disk while allowing an operator to observe a relay video image that is currently in progress. In response to the generation of a recording command signal, a recording head is set to a recording mode and a disk address of the recording head at that time is stored as a determinate disk address. In response to the generation of a stop command signal, the recording mode is canceled and a disk address of the recording head at that time is stored as a temporary disk address. In the case where a skip command signal is generated during the recording mode, the recording head is moved to the determinate disk address stored at the time of the start of the recording mode. In the case where the skip command signal is generated in a mode other than the recording mode, the recording head is moved to the temporary disk address.

Abstract: A disc playing and controlling apparatus which includes a plurality of magazine type disc players. When a first disc player is operating, the apparatus controls the other disk players to find and load a disc holding the next song to be played. Before searching for the next song, the controller determines whether one player is already set in a standby position or whether the next song is located in the player currently being operated. If no player has been set for the next program, the apparatus reads the next selection from a program list and identifies which magazine contains the selected program based on a data map. The map stores each player number and magazine number in an one-to-one relation with the table of contents data for each song.

Abstract: A tracking servo apparatus is disclosed which detects the change in the level of tracking error signal per unit time when the information reading spot passes a position on the track at its center in the converging period of the servo pull-in operation after a decelerating pulse has been generated and, when the amount of the detected change is over reference value, controls such that at least either one of the equalizer characteristic and the gain is changed for a predetermined period of time after the detection.

Abstract: In a tracking servo system for use in a disc player having a pickup, for playing an information recording disc having a recording track, the peak value of the tracking error signal obtained during a track jump operation is detected, and at least one of the pulse width and the pulse height of the deceleration pulse for the jump operation is varied in response to the detected peak value. With this feature, an appropriate control amount for the track jump operation corresponding to the track pitch is obtained even if there is a change in the track pitch.

Abstract: A tracking servo system for use in a disc player having a pickup, for playing an information recording disc having a recording track, the tracking servo system comprises an equalizing circuit for compensating for the frequency characteristic of the tracking error signal for the tracking servo operation, the equalizing circuit means performing a compensating operation in accordance with a predetermined compensation characteristic during a normal playback of the recording disc.

Abstract: There is provided a tracking servo apparatus of a disk player comprising: off-track detecting means for detecting that an information reading spot of a pickup does not exist on an information recording track of a disk and for generating an off-track signal; and level control means for increasing an amplitude of a tracking error signal when the off-track signal exists, whereby the stable tracking servo operation can be executed.

Abstract: A high-speed search method for searching a target address and for use in a disc player system having a slider for positioning a pickup for reading an information signal recorded on a disc as tracks, in a disc radius, and a tracking servo system for causing an information detecting point of the pickup to follow the track. An accelerating-and-decelerating move control mode in which the slider is accelerated and subsequently decelerated with the tracking servo loop open, and a constant speed move control mode in which the slider is moved at a constant speed by using address data obtained from a signal from the pickup are prepared, and a distance from a present position of the pickup to the target address is detected.