Abstract: An optical pickup device includes an objective lens holder having a pair of tracking coils and an objective lens fixed thereto, and a pair of magnets. The pair of tracking coils are rectangular or square in geometry. When the objective lens is not displaced in a tracking direction, one tracking coil has a vertical portion closer to a centerline, which passes through the pair of magnets at their respective centers, at a position distant from the centerline in a positive direction of rotation by a prescribed angle ? and the other tracking coil has a vertical portion closer to the centerline at a position distant from the centerline in a negative direction of rotation by the prescribed angle ?.

Abstract: As the result of the detection of the runaway of the optical disc when the light pickup cannot detect sync signal in the reproducing signal sent from the optical disc, the control circuit turns off the tracking servo mechanism which controls the tracking of the optical disc by the light pickup. The direction of rotation of the optical disc that is running away is detected by comparing the initial mirror count value obtained by counting for a predetermined period of time the mirror pulse detected in correspondence with the RF signal based on the reproducing signal, with the mirror count value during braking obtained by counting the mirror pulse for the predetermined period of time when the spindle motor is applied with the brake pulse. The brake signal working in the direction opposite to the detected direction of rotation is applied to the spindle motor so as to stop the rotation of the optical disc.

Abstract: In a power on/off circuit apparatus, if a microcomputer malfunctions, an on/off operation of a power switch is executed, and thereby, the microcomputer is reset. A non-volatile memory stores an operating state of components just before the power switch is operated. Therefore, if the microcomputer malfunctions, without unplugging an AC cord, it is possible to reset the microcomputer by the power switch, and thus, to carry the components from a state just before the reset to the next operating state.

Abstract: A DVD auto-changer includes a controller, and in the DVD auto-changer, an all-repeat-mode that a plurality of disks stocked are exchanged to be successively reproduced can be set. The controller determines whether the all-repeat-mode is set or not, and unconditionally reproduces a story portion upon exchanging the disks when the all-repeat-mode is set. In other words, the controller obtains a start address of the story portion, and reproduces it from the start address.

Abstract: When a run-away phenomenon of an optical disk occurs, a control circuit detects a rotational direction of the optical disk that runs away by comparing an initial track count value and a braking time track count value. The initial track count value is a value calculated by counting track pulses corresponding to a tracking error signal for a predetermined time when a tracking servo is turned off. The braking time track count value is a value calculated by counting the track pulses corresponding to the tracking error signal for a predetermined time, when a brake pulse is applied to the spindle motor.

Abstract: A portable disk player capable of playing a disk while carrying, includes: a reproducing part for playing a disk; a battery for supplying power for each part; a main title detecting unit for detecting playing a main title recorded in the disk, wherein when a power-saving mode is set, the power is turned off at an end of playing the main title.

Abstract: In an optical disc apparatus 1, when a supply of operation power to the main unit is started, an objective lens 4a is moved to a focusing position (a position where the focus is placed on a reflective recording layer of an optical disc 10) which is determined in the design level. If the quantity of reflected light at this time is equal to or larger than a threshold SH, it is judged that the optical disc 10 is set in the main unit. Therefore, a time period required for detecting whether the optical disc 10 is set in the main unit or not can be shortened.

Abstract: An optical pickup device includes an objective lens holder having a pair of tracking coils and an objective lens fixed thereto, and a pair of magnets. The pair of tracking coils are rectangular or square in geometry. When the objective lens is not displaced in a tracking direction, one tracking coil has a vertical portion closer to a centerline, which passes through the pair of magnets at their respective centers, at a position distant from the centerline in a positive direction of rotation by a prescribed angle ? and the other tracking coil has a vertical portion closer to the centerline at a position distant from the centerline in a negative direction of rotation by the prescribed angle ?.

Abstract: A control part 7 detects pulse widths of four continuous pulses, and a pulse width w1 of a pulse detected first is compared in size with a pulse width w2 of a pulse detected second and when w2 is larger, normality is determined. The pulse width w2 of the pulse detected second is compared in size with a pulse width w3 of a pulse detected third and when w3 is larger, normality is determined. The pulse width w3 of the pulse detected third is compared in size with the pulse width w1 of the pulse detected first and when w1 is larger, normality is determined. In the above first to fourth determinations, when the number of cases determined as normality is two times or more, normal rotation is determined, and otherwise, reverse rotation is determined.

Abstract: As the result of the detection of the runaway of the optical disc when the light pickup cannot detect sync signal in the reproducing signal sent from the optical disc, the control circuit turns off the tracking servo mechanism which controls the tracking of the optical disc by the light pickup. The direction of rotation of the optical disc that is running away is detected by comparing the initial mirror count value obtained by counting for a predetermined period of time the mirror pulse detected in correspondence with the RF signal based on the reproducing signal, with the mirror count value during braking obtained by counting the mirror pulse for the predetermined period of time when the spindle motor is applied with the brake pulse. The brake signal working in the direction opposite to the detected direction of rotation is applied to the spindle motor so as to stop the rotation of the optical disc.

Abstract: When a run-away phenomenon of an optical disk occurs, a control circuit detects a rotational direction of the optical disk that runs away by comparing an initial track count value and a braking time track count value. The initial track count value is a value calculated by counting track pulses corresponding to a tracking error signal for a predetermined time when a tracking servo is turned off. The braking time track count value is a value calculated by counting the track pulses corresponding to the tracking error signal for a predetermined time, when a brake pulse is applied to the spindle motor.

Abstract: A control part 7 detects pulse widths of four continuous pulses, and a pulse width w1 of a pulse detected first is compared in size with a pulse width w2 of a pulse detected second and when w2 is larger, normality is determined. The pulse width w2 of the pulse detected second is compared in size with a pulse width w3 of a pulse detected third and when w3 is larger, normality is determined. The pulse width w3 of the pulse detected third is compared in size with the pulse width w1 of the pulse detected first and when w1 is larger, normality is determined. In the above first to fourth determinations, when the number of cases determined as normality is two times or more, normal rotation is determined, and otherwise, reverse rotation is determined.

Abstract: In an optical disc apparatus 1, when a supply of operation power to the main unit is started, an objective lens 4a is moved to a focusing position (a position where the focus is placed on a reflective recording layer of an optical disc 10) which is determined in the design level. If the quantity of reflected light at this time is equal to or larger than a threshold SH, it is judged that the optical disc 10 is set in the main unit. Therefore, a time period required for detecting whether the optical disc 10 is set in the main unit or not can be shortened.

Abstract: A DVD auto-changer includes a controller, and in the DVD auto-changer, an all-repeat-mode that a plurality of disks stocked are exchanged to be successively reproduced can be set. The controller determines whether the all-repeat-mode is set or not, and unconditionally reproduces a story portion upon exchanging the disks when the all-repeat-mode is set. In other words, the controller obtains a start address of the story portion, and reproduces it from the start address.

Abstract: A multi-layer recording medium reproducing device having an automatic adjustment mode of automatically performing servo adjustment to reproduce a multi-layer optical disk. The device includes a storing section which, during the automatic adjustment mode, performs the servo adjustment of recording layers of the optical disk respectively for predetermined periods of time, and stores the resultant service adjustment values respectively for the recording layers; and a servo adjustment control section which, during a reproduction of the optical disk, reads from the storing section a servo adjustment value corresponding to one of the recording layers to be reproduced, and performs the servo adjustment to reach the servo adjustment value thus read.

Abstract: A multi-layer recording medium reproducing device having an automatic adjustment mode of automatically performing servo adjustment to reproduce a multi-layer optical disk. The device includes a storing section which, during the automatic adjustment mode, performs the servo adjustment of recording layers of the optical disk respectively for predetermined periods of time, and stores the resultant service adjustment values respectively for the recording layers; and a servo adjustment control section which, during a reproduction of the optical disk, reads from the storing section a servo adjustment value corresponding to one of the recording layers to be reproduced, and performs the servo adjustment to reach the servo adjustment value thus read.

Abstract: In a power on/off circuit apparatus, in the case where a microcomputer 4 runs away, an on/off operation of a power switch 3 is carried out, and thereby, the microcomputer 4 is reset. A non-volatile memory 14 stores an operating state of equipments just before the power switch 3 is operated. Therefore, when the microcomputer 4 makes a malfunction, without plugging an AC code out of a receptacle, it is possible to reset the microcomputer 4 by the power switch 3, and thus, to transfer the equipments from a state just before reset to the next operating state.