Abstract: According to one embodiment, a disk drive comprises a head and a heating actuator. The head is configured to slide over a rotating disk in contact with a surface of the disk. The heating actuator is configured to vary a state of contact between the head and the disk by being expanded by supplied heat. The head comprises the heating actuator.

Abstract: A novel technology for lowering the surface free energy is provided. A treatment surface is irradiated with ultraviolet light in a gas containing a fluorine-containing organic substance, thereby forming a coating layer on the treatment surface.

Abstract: According to one embodiment, in a disk drive, a voice coil motor is controlled to cause a head to minutely vibrate in a radial direction on a track of a disk. When the voice coil motor vibrates the head in the radial direction of the disk, frictional force occurring between the disk and the head is calculated based on the driving force of the voice coil motor generated to vibrate and detected positional information, thereby measuring frictional characteristics.

Abstract: An AC power source is connected to a write coil mounted on a head slider for determination of contact of a head slider with a storage medium. The AC power source outputs the alternating current having a specific frequency. A measuring circuit measures a sequence of indices for the alternating current supplied to the write coil. A component corresponding to the specific frequency is extracted from the sequence of the indices. This serves to eliminate components corresponding to frequencies other than the specific frequency, namely noise. A detecting circuit detects contact between the head slider and the storage medium based on a change in the amplitude of the sequence appearing at the specific frequency. The contact can thus reliably be detected between the head slider and the storage medium.

Abstract: A method of detecting a gap between a head and a recording medium in an information-recording/reproducing apparatus that uses the head to record and reproduce information in and from the recording medium. In the method, the gap between the head and the recording medium is alternately increased and decreased, thereby gradually reducing the gap between the head and the recording medium. A detection signal is detected from which to determine a contact between the head or a slider supporting the head and the recording medium. When it is determined that the head or the slider has contacted the recording medium, the head is stopped and moved away from the recording medium to a prescribed position, and data representing a distance the head has moved to contact the recoding medium is acquired.

Abstract: A first wiring connects a first actuator to a controlling circuit on a head slider. The second wiring connects the second actuator to the first wiring in parallel with the first actuator. A first rectifying element is inserted in the first wiring. A second rectifying element is inserted in the second wiring. When electric voltage is applied to the first and second wiring in a first direction, the electric voltage acts on the first wiring. Only the first actuator is allowed to receive the electric voltage. When electric voltage is applied to the first and second wiring in a second direction opposite to the first direction, the electric voltage acts on the second wiring. Only the second actuator is allowed to receive the electric voltage in the second direction.

Abstract: A method of detecting a gap between a head and a recording medium in an information-recording/reproducing apparatus that uses the head to record and reproduce information in and from the recording medium. In the method, the gap between the head and the recording medium is alternately increased and decreased, thereby gradually reducing the gap between the head and the recording medium. A detection signal is detected from which to determine a contact between the head or a slider supporting the head and the recording medium. When it is determined that the head or the slider has contacted the recording medium, the head is stopped and moved away from the recording medium to a prescribed position, and data representing a distance the head has moved to contact the recoding medium is acquired.

Abstract: A discretization processing method for transforming a transfer function in continuous time systems to a transfer function in discrete time systems is disclosed. To obtain the new transfer function, angular frequency ?a of the original transfer function in continuous time systems is transformed to angular frequency ?c using the bilinear z-transform of the inverse characteristic. In the discretion processing result, the equivalent characteristics of the original transfer function in continuous time systems can be obtained by performing the bilinear z-transform against the new transfer function in continuous time systems having been obtained by the angular frequency transformation of inverse characteristic.

Abstract: A track servo control perform follow-up control of an optical beam to a track of an optical disk, and control the vibration of the optical beam due to the ID pit noise of the optical disk. The control system is comprised of a feedback control block for feedback-controlling the actuator by the track error signal from the actuator and the learning control block. Since the optical disk ID pit noise is periodic noise, the learning control block learns this, inputs the learning result to the feedback control system. The learning result is subtracted from the learning input, and the signal after subtraction is learned in order to converge the learning. Therefore even if the periodic ID pit noise is applied, this noise can be removed from the control loop and the vibration of the actuator due to periodic noise can be decreased, making a stable track follow-up operation possible.

Abstract: The present invention implements a servo system which can support changes of the higher resonance frequencies of the actuator with a simple configuration at low cost.

Abstract: The invention relates to an information recording apparatus including a head that is disposed so as to face a recording medium, and records information in the recording medium and/or reproduces information therefrom, and a head actuator for moving the head toward and away from the recording medium. The apparatus further comprises a capacitor electrically charged by a power source; and a driving processor for driving the head actuator with electric charge accumulated in the capacitor in accordance with a voltage of the power source, and for retracting the head to a position away from the recording medium.

Abstract: A digital servo controller generates a control signal from an analog observation signal using an output equation, state equation or a transfer function, and performs high precision servo-control with an inexpensive configuration. In a digital servo which executes an output equation yd[k]=C·x[k]+D·ud[k] and state equation x[k+1]=A·x[k]+B·ud[k]. The digital servo comprises a digital processor which outputs the second term D·ud[k] of the output equation by an analog circuit, and outputs the first term C·x[k] earlier for Ts/2. The digital servo also has a digital processor which executes the direct term of the output equation at period Ts/N (N is a 2 or higher natural number), which is 1/N of the basic operation period Ts, and updates the first term with the same delay time as the average delay time Ts/(2N) of the direct term.

Abstract: A digital servo controller generates a control signal from an analog observation signal using an output equation, state equation or a transfer function, and performs high precision servo-control with an inexpensive configuration. In a digital servo which executes an output equation yd[k]=C·x[k]+D·ud[k] and state equation x[k+1]=A·x[k]+B·ud[k]. The digital servo comprises a digital processor which outputs the second term D·ud[k] of the output equation by an analog circuit, and outputs the first term C·x[k] earlier for Ts/2. The digital servo also comprises a digital processor which executes the direct term of the output equation at period Ts/N (N is a 2 or higher natural number), which is 1/N of the basic operation period Ts, and updates the first term with the same delay time as the average delay time Ts/(2N) of the direct term.

Abstract: The invention relates to an information recording apparatus including a head that is disposed so as to face a recording medium, and records information in the recording medium and/or reproduces information therefrom, and a head actuator for moving the head toward and away from the recording medium. The apparatus further comprises a capacitor electrically charged by a power source; and a driving processor for driving the head actuator with electric charge accumulated in the capacitor in accordance with a voltage of the power source, and for retracting the head to a position away from the recording medium.

Abstract: A discretization processing method for transforming a transfer function in continuous time systems to a transfer function in discrete time systems is disclosed. To obtain the new transfer function, angular frequency &ohgr;a of the original transfer function in continuous time systems is transformed to angular frequency &ohgr;c using the bilinear z-transform of the inverse characteristic. In the discretion processing result, the equivalent characteristics of the original transfer function in continuous time systems can be obtained by performing the bilinear z-transform against the new transfer function in continuous time systems having been obtained by the angular frequency transformation of inverse characteristic.

Abstract: A track servo control perform follow-up control of an optical beam to a track of an optical disk, and control the vibration of the optical beam due to the ID pit noise of the optical disk. The control system is comprised of a feedback control block for feedback-controlling the actuator by the track error signal from the actuator and the learning control block. Since the optical disk ID pit noise is periodic noise, the learning control block learns this, inputs the learning result to the feedback control system. The learning result is subtracted from the learning input, and the signal after subtraction is learned in order to converge the learning. Therefore even if the periodic ID pit noise is applied, this noise can be removed from the control loop and the vibration of the actuator due to periodic noise can be decreased, making a stable track follow-up operation possible.

Abstract: The present invention implements a servo system which can support changes of the higher resonance frequencies of the actuator with a simple configuration at low cost.