Abstract: A vibration absorber provided on an optical disk drive module of a disk drive for suppressing vibration produced by the optical disk drive module at various speeds. The vibration absorber at least has a body, dampers, elastic members, an actuator and a controller. The body is secured on the optical disk drive module. The dampers elastically and vertically shift on the body. The elastic members are provided on the body for providing elasticity in shifting of the damper. The actuator is provided on the body and coupled to the damper for providing a driving force for the vertical shifting of the damper. The controller controls the driving force outputted by the actuator based on the change in rotational speed of the optical disk drive module, so as to change the elasticity in vertical shifting of the damper to reduce the shifting and corresponding vibration of the optical disk drive module.

Abstract: An optical pickup head and an electromagnetic actuating device thereof are provided. The electromagnetic actuating device is used to move an objective lens carrier having an objective lens assembly to form an optical pickup head. The electromagnetic actuating device includes at least a magnet, at least a coil, and at least a yoke. The magnet is spaced apart from the objective lens carrier by a distance, and the coil is disposed at the objective lens carrier, for generating an electromagnetic force to interact with the magnet. The yoke is spaced apart from the objective lens carrier by a distance, in which the yoke has a protruding part that extends towards the objective lens carrier and is used to attract magnetic flux lines produced by the magnet, and thus making the magnetic flux that passes through the coil be distributed evenly.

Abstract: A sensorless driving method for a brushless DC motor is provided. The time for the motor to rotate an electrical angle 60° is obtained by alternatively counting the occurrences of zero crossings with two counters and comparing the counted values, and the motor is delayed an electrical angle of 30°, by which a precise commutating time is obtained. The driving method provides a mask-based phase shift digital detection mechanism for effectively detecting true zero-crossing points. The driving method further provides an inhabitation mechanism with the function of soft-switch for inhibiting noise caused by transistor switching. By using these two counters, the time for the motor to rotate two electrical angles 30°??? and 30°+?? are obtained and stored in two registers. The time period before and after the commutating point is added into a pulse width modulation (PWM) signal to reduce the noise and vibration.

Abstract: A sensorless driving method for a brushless DC motor is provided. The time for the motor to rotate an electrical angle 60° is obtained by alternatively counting the occurrences of zero crossings with two counters and comparing the counted values, and the motor is delayed an electrical angle of 30°, by which a precise commutating time is obtained. The driving method provides a mask-based phase shift digital detection mechanism for effectively detecting true zero-crossing points. The driving method further provides an inhabitation mechanism with the function of soft-switch for inhibiting noise caused by transistor switching. By using these two counters, the time for the motor to rotate two electrical angles 30°??? and 30°+?? are obtained and stored in two registers. The time period before and after the commutating point is added into a pulse width modulation (PWM) signal to reduce the noise and vibration.

Abstract: An optical pickup head and an electromagnetic actuating device thereof are provided. The electromagnetic actuating device is used to move an objective lens carrier having an objective lens assembly to form an optical pickup head. The electromagnetic actuating device includes at least a magnet, at least a coil, and at least a yoke. The magnet is spaced apart from the objective lens carrier by a distance, and the coil is disposed at the objective lens carrier, for generating an electromagnetic force to interact with the magnet. The yoke is spaced apart from the objective lens carrier by a distance, in which the yoke has a protruding part that extends towards the objective lens carrier and is used to attract magnetic flux lines produced by the magnet, and thus making the magnetic flux that passes through the coil be distributed evenly.

Abstract: The present invention provides a three-phase motor stator. The shape of the three-phase motor stator is defined by an optimum pole-tooth ratio for reducing the cogging torque of the motor and increasing the efficiency of the motor. The three-phase motor stator includes at least one plate board. The plate board has a circular hole. A plurality of pole-teeth protrude from the rim of the circular hole and the pole-teeth are symmetric. An opening slot is individually located between two adjacent pole-teeth. The pole-tooth ratio ? defined by the tooth angle of a single pole-tooth divided by the pole pitch of two adjacent pole-teeth is between 0.65 and 0.85.

Abstract: A method and an apparatus for estimating the position of a moving part of a linear actuator are provided. The method comprises the following steps. Move the moving part towards a target position. Receive magnetic signals generated by the magneto-resistive sensor of the linear actuator, which include a sine signal and a cosine signal. Then, generate a first square wave, a second square wave, and a regional square wave based on the sine signal and the cosine signal. Generate a saw-tooth wave based on the sine signal, the cosine signal, the second square wave, and the regional square wave. Next, calculate the number of regions which the moving part is across from the origin point based on the first square wave, the second square wave, and the regional square wave. Finally, estimate the current position of the moving part based on the saw-tooth wave and the number of regions.

Abstract: A method for measuring a surface structure of a near-field object is provided. A light source produces at least a first light beam and a second light beam; guiding the first light beam and the second light beam to enter the SIL for interacting with the object surface. This method can be used in, for example, a near-field optical disc storage system, wherein reflection intensities of the first and second light beams are used to measure two distances between the SIL and the optical disc at two positions corresponding to the first and second light beams. A surface structure, such as a tilt angle or an average distance between the disc and the SIL or disc roughness, is obtained by analyzing the above-mentioned positions and distances. The first and second light beams are produced, for example, by a diffraction technology or by a single laser diode with multiple beams.

Abstract: A method and an apparatus for estimating the position of a moving part of a linear actuator are provided. The method comprises the following steps. Move the moving part towards a target position. Receive magnetic signals generated by the magneto-resistive sensor of the linear actuator, which include a sine signal and a cosine signal. Then, generate a first square wave, a second square wave, and a regional square wave based on the sine signal and the cosine signal. Generate a saw-tooth wave based on the sine signal, the cosine signal, the second square wave, and the regional square wave. Next, calculate the number of regions which the moving part is across from the origin point based on the first square wave, the second square wave, and the regional square wave. Finally, estimate the current position of the moving part based on the saw-tooth wave and the number of regions.

Abstract: An optical device. At least one guide bar is connected to a base. A coil is disposed in the base. A central axis of the coil in an optical axis direction of the optical device is parallel to a central axis of the guide bar in the optical axis direction. A lens housing slidably fits on the guide bar. A central axis of the lens housing in the optical axis direction is parallel to that of the guide bar. The lens housing slides along the central axis of the guide bar. A magnetic member is connected to the lens housing opposite the coil, providing a first magnetic field. When the coil is energized to generate a second magnetic field, the lens housing slides on the guide bar by attraction or repulsion of the first and second magnetic fields.

Abstract: An optical device. A guide bar is connected to a base, with a first central axis in an optical axis direction of the optical device. A coil slides on the guide bar and has a second central axis in the optical axis direction and a first central elevation axis. The second central axis is perpendicular to the first central elevation axis. A fixed magnetic member is disposed in the coil and has a central magnetizing axis and a second central elevation axis. The central magnetizing axis is perpendicular to the second central elevation axis and aligned with the second central axis of the coil. The second central elevation axis is separated from the first central elevation axis. A lens housing is connected to the coil. When the coil is energized by application of a current, a magnetic force is generated, moving the coil and lens housing along the guide bar.

Abstract: An optical device. At least one guide bar is connected to a base. A coil is disposed in the base. A central axis of the coil in an optical axis direction of the optical device is parallel to a central axis of the guide bar in the optical axis direction. A lens housing is slidably fitted on the guide bar. A central axis of the lens housing in the optical axis direction is parallel to that of the guide bar. The lens housing slides along the central axis of the guide bar. A magnetic member is connected to the lens housing opposite the coil, providing a first magnetic field. When the coil is energized to generate a second magnetic field, the lens housing slides on the guide bar by attraction or repulsion of the first and second magnetic fields.

Abstract: A method for measuring the electromotive force of motors is provided. The method enables the motor to rotate in single phase mode, and thereby measures the electromotive force constant of the motor. According to the principles and the method, motors do not have to work in close-loop. Neither encoders for detecting angle displacement or angle velocity are needed for motors, nor the motor impedance or current have to obtain in advance. Compared with the prior art, the disclosed method is more efficiency and economic.

Abstract: A method for measuring the electromotive force of motors is provided. The method enables the motor to rotate in single phase mode, and thereby measures the electromotive force constant of the motor. According to the principles and the method, motors do not have to work in close-loop. Neither encoders for detecting angle displacement or angle velocity are needed for motors, nor the motor impedance or current have to obtain in advance. Compared with the prior art, the disclosed method is more efficiency and economic.

Abstract: A magnetic bearing includes a base, a spindle rotatably mounted onto the base and a magnetic portion mounted between the base and the spindle to provide a magnetic repulsion that suspends the spindle. The magnetic portion further includes an inner magnetic portion and an outer magnetic portion that repulse against each other. The outer magnetic portion is located around the inner magnetic portion so that the inner magnetic portion and the spindle are suspended. Therefore, mechanical friction in the magnetic bearing is minimized.

Abstract: The invention pertains to a method for determining whether a rotor is good in magnetic induction by measuring the electromotive force (emf) of a motor. A standard stator of the motor is prepared as the standard of measurement. A set of induction coil is wound upon the standard stator so that when the rotor is combined with the standard stator and is subject to running by a driver, the induction coil can detect the back-emf signal generated by the rotor, by which the rotor quality can be determined. Since the measuring method disclosed in the invention is performed within the closed system composed of the rotor and the stator, the result is not only close to a real motor in rotation, the detection is simple and free from the problem of axis alignment. Thus, this method can increase the production efficiency of the product line.

Abstract: A magnetic bearing includes a base, a spindle rotatably mounted onto the base and a magnetic portion mounted between the base and the spindle to provide a magnetic repulsion that suspends the spindle. The magnetic portion further includes an inner magnetic portion and an outer magnetic portion that repulse against each other. The outer magnetic portion is located around the inner magnetic portion so that the inner magnetic portion and the spindle are suspended. Therefore, mechanical friction in the magnetic bearing is minimized.

Abstract: The invention pertains to a method for determining whether a rotor is good in magnetic induction by measuring the electromotive force (emf) of a motor. A standard stator of the motor is prepared as the standard of measurement. A set of induction coil is wound upon the standard stator so that when the rotor is combined with the standard stator and is subject to running by a driver, the induction coil can detect the back-emf signal generated by the rotor, by which the rotor quality can be determined. Since the measuring method disclosed in the invention is performed within the closed system composed of the rotor and the stator, the result is not only close to a real motor in rotation, the detection is simple and free from the problem of axis alignment. Thus, this method can increase the production efficiency of the product line.

Abstract: The present invention is a starting method for brushless DC motor and a device for the same, especially adapted to provide the starting method for a single-phase DC brushless motor in an open circuit and the device for the same. According to the art as disclosed in the present invention, there are two successive steps in starting a motor. An oscillator signal is transmitted to the driver at first, which causes the motor to oscillate in both clockwise and counter-clockwise direction. An operating signal is then sent to cause the motor to rotate normally in one direction once the motor is out of the dead initiating position. By that the rotor can be triggered out of the dead initiating position when the motor is going to start and the motor can be smoothly operated under the low cogging torque.

Abstract: A method for designing an optimal bi-axial type of magnetic gear system that uses magnetic coupling for transmitting torque in order to be free from the defects caused by using a conventional mechanical gear system. A non-coaxial rather than a conventional coaxial type of magnetic gear design is considered for this invention. For the non-coaxial magnetic gear system, the size of torque will depend on the number of poles magnetized out of the strong magnetic material around the magnetic gear. Therefore, the optimum number of magnetized poles must be carefully selected for a set of specified conditions such that the largest torque can be obtained. An optimal magnetic gear system can be produced by the method in this invention.