Abstract: Compositions and methods for producing compositions comprising a monoamine-endcapped polyimide component. Based on a gas chromatography mass spectroscopy analysis of a surface rinse of the composition performed at room temperature, the composition can have at least one surface with less than or equal to 5 ppb releasable phosphorous residuals, and less than or equal to 5 ppb releasable volatile organic compound residuals. The composition can also comprise less than or equal to 10 ppb combined releasable residuals. Because of the very low levels of residual contamination, the compositions can be used to produce a variety of articles including a disk drive.

Abstract: To prevent the peak power/current consumption from exceeding a permitted level when more than one active mechanical mechanism of an electronic device (e.g., an optical storage apparatus) is involved in accomplishing a particular task, a method of controlling the electronic device is provided. The electronic device has a plurality of mechanical mechanisms including at least a first mechanical mechanism and a second mechanical mechanism. The method includes following steps: driving the first mechanical mechanism by applying a first control signal to the first mechanical mechanism; driving the second mechanical mechanism by applying a second control signal to the second mechanical mechanism; comparing the first control signal with a first predetermined threshold, and accordingly generating a first comparison result; and selectively adjusting the second control signal according to at least the first comparison result.

Abstract: An optical disc apparatus comprising: a spindle motor configured to drive a turntable on which an optical disc is loaded to rotate; a first substrate on which a first support member rotatably supporting a rotation shaft of the spindle motor is fixed, and on which a second support member is formed at a position adjacent to the spindle motor; a second substrate; an optical pickup device; and a guide member configured to guide the optical pickup device in a radial direction of the optical disc loaded on the turntable, one end of the guide member being supported by the second support member on the first substrate and fixed to a fixing member on the second substrate, and the other end of the guide member being fixed to the fixing member on the second substrate.

Abstract: A sampling circuit samples, while running a motor at a predetermined rotational speed, over a predetermined period a back electro-motive force induced at one end of at least one phase coil, with one end of each phase coil of the motor being brought to a high impedance. A waveform data generating circuit holds as waveform data SIN the back electro-motive force beforehand sampled by the sampling circuit. A PWM signal generating circuit sequentially reads the waveform data SIN from the waveform data generating circuit to generate a PWM signal Spwm, the pulse width of which is modulated.

Abstract: There is provided a motor including a rotating member coupled with a shaft and rotating in connection with the shaft, and a fixing member having the shaft inserted thereinto to support the shaft and including a round part whose outer surface corresponding to the rotating member is formed to be rounded to thereby allow oil to be sealed between the round part and the rotating member.

Abstract: There is provided a motor including: a rotating member coupled to a shaft and rotating in connection with the shaft; a stationary member having the shaft inserted therein and supporting the shaft; a wall part protruding from a surface of the rotating member and allowing oil to be sealed between the rotating member and the stationary member; and a pumping groove formed in at least one of the wall part and an outer surface of the stationary member corresponding to the wall part and pumping the oil between the shaft and the stationary member.

Abstract: The present invention discloses a 3-phase brushless DC motor controller, which comprises: a unit for generating a PWM signal; an ADC for converting a back electromotive force (BEMF) signal from an analog form into a digital form; a synchronization and extraction unit operating in synchronization in part with the PWM signal for extracting the digital BEMF signal to obtain a corresponding ZCP signal; and a unit for judging whether a commutation operation is to be performed according to a change of the corresponding ZCP signal. A wait instruction and a delay instruction help to accurately acquire the digital BEMF signal.

Abstract: There is provided a hydrodynamic bearing assembly that includes: a sleeve with an axial hole into which a shaft is inserted; a radial dynamic pressure unit formed on at least one of an outer diameter of the shaft and an inner diameter of the sleeve; and a sub-radial dynamic pressure unit formed on at least one of the outer diameter of the shaft and the inner diameter of the sleeve in an upper part in an axial direction of the radial dynamic pressure unit, wherein an oil interface formed in an axial hole between the radial dynamic pressure unit and the sub-radial dynamic pressure unit moves up toward the sub-radial dynamic pressure unit as the temperature of a motor rises due to driving of the motor.

Abstract: The invention discloses radio frequency zero crossing signal generators for optical disc drives, comprising a controllable low pass filter, a comparator, and a control circuit. The controllable low pass filter evaluates an average level of the magnitude of a radio frequency ripple from an optical disc drive. The comparator compares the radio frequency ripple to the average level evaluated by the controllable low pass filter to generate a radio frequency zero crossing signal. When the optical disc drive reads a fingerprint defect on an optical disc, the control circuit adjusts a cut-off frequency of the controllable low pass filter to adjust the speed at which the controllable low pass filter evaluates the average level.

Abstract: A back electromotive force detection circuit detects a zero-crossing point by comparing a back electromotive force Vu which occurs in at least one coil of a motor with a center tap voltage at a common node of the coils, and outputs a back electromotive force detection signal. A switching control circuit controls the switching states of multiple switching circuits based upon the back electromotive force detection signal, thereby adjusting the current flowing through the coils of the motor. A window generating circuit outputs a window signal at a predetermined level during a period obtained by multiplying the cycle of the back electromotive force detection signal by a predetermined coefficient before the detection of the zero-crossing point. The switching control circuit stops the switching operation of the switching circuit during a period in which the window signal is maintained at the predetermined level, thereby setting the state to the high impedance state that corresponds to a non-driving period.

Abstract: A device and method for reducing power consumption of an optical drive are proposed. The present invention samples a carrier control signal and then compares the samples of the signals with predetermined threshold signals. According to the comparison result, the present invention increases or decreases an output signal index. The variation of the output signal index is used to control phases of diphase excitation control signals so as to control the rotation direction of a motor or make it stop. The present invention need not output the diphase excitation control signals continuously. It only needs to output a predetermined number of the diphase excitation control signals after the output signal index is increased or decreased. Hence, the present invention reduces the time for outputting the control signals and greatly reduces the power consumption of the optical drive thereby.

Abstract: A disk device includes a frame, an optical pickup and a shock absorbing component. The frame has a receiving component. The optical pickup is slidable with respect to the frame. The shock absorbing component is fixedly coupled to the optical pickup and arranged to selectively contact the receiving component of the frame. The shock absorbing component includes a support portion and a spring piece. The spring piece has a first end portion that is fixedly coupled to the optical pickup and a second end portion that is spaced from the support portion in an unloaded rest state and that contacts the support portion to support the spring piece at both the first and second end portions with respect to the optical pickup when the spring piece is pushed by the receiving component of the frame to a loaded state.

Abstract: Provided are ultrasonic actuators and magnetic recording apparatuses that are stably equipped with superior driving performance without making the apparatus complex or raising cost. By providing an approximately equilateral triangular shaped vibrating member provided with piezoelectric deformation members that expand and contract upon the application of a driving signal, and a moving member that is in pressure contact with the three vertices of the vibrating member to cause relative movement with respect to the vibrating member. The moving member is caused to move relative to the vibrating member due to elliptical vibrations in the same rotational direction in basically the three vertices of the vibrating member due to a deformation vibration of the piezoelectric deformation parts.