Abstract: A display apparatus includes a scanning assembly that scans about two or more axes, typically in a raster pattern. A plurality of light sources emit light from spaced apart locations toward the scanning assembly such that the scanning assembly simultaneously scans more than one of the beams. The scanning assembly is a resonant scanning assembly with a variable resonant frequency. The resonant frequency of the scanning assembly can be actively controlled by controlling partial pressure of fluids in a package containing the scanning assembly. In one embodiment, the increased partial pressure increases the mass of a scanning mirror, thereby changing the resonant frequency. In another embodiment, a gas absorbing material is coupled to a support arm that carries a scanning mirror. As the gas absorbing material absorbs gas, its physical properties change, thereby shifting the resonant frequency of the scanning assembly.

Abstract: A display apparatus includes a scanning assembly that scans about two or more axes, typically in a raster pattern. A plurality of light sources emit light from spaced apart locations toward the scanning assembly such that the scanning assembly simultaneously scans more than one of the beams. The scanning assembly is a resonant scanning assembly with a variable resonant frequency. The resonant frequency of the scanning assembly can be actively controlled by controlling partial pressure of fluids in a package containing the scanning assembly. In one embodiment, the increased partial pressure increases the mass of a scanning mirror, thereby changing the resonant frequency. In another embodiment, a gas absorbing material is coupled to a support arm that carries a scanning mirror. As the gas absorbing material absorbs gas, its physical properties change, thereby shifting the resonant frequency of the scanning assembly.

Abstract: A display apparatus includes a scanning assembly that scans about two or more axes, typically in a raster pattern. A plurality of light sources emit light from spaced apart locations toward the scanning assembly such that the scanning assembly simultaneously scans more than one of the beams. The scanning assembly is a resonant scanning assembly with a variable resonant frequency. The resonant frequency of the scanning assembly can be actively controlled by controlling partial pressure of fluids in a package containing the scanning assembly. In one embodiment, the increased partial pressure increases the mass of a scanning mirror, thereby changing the resonant frequency. In another embodiment, a gas absorbing material is coupled to a support arm that carries a scanning mirror. As the gas absorbing material absorbs gas, its physical properties change, thereby shifting the resonant frequency of the scanning assembly.

Abstract: A display apparatus includes a scanning assembly that scans about two or more axes, typically in a raster pattern. A plurality of light sources emit light from spaced apart locations toward the scanning assembly such that the scanning assembly simultaneously scans more than one of the beams. The scanning assembly is a resonant scanning assembly with a variable resonant frequency. The resonant frequency of the scanning assembly can be actively controlled by controlling partial pressure of fluids in a package containing the scanning assembly. In one embodiment, the increased partial pressure increases the mass of a scanning mirror, thereby changing the resonant frequency. In another embodiment, a gas absorbing material is coupled to a support arm that carries a scanning mirror. As the gas absorbing material absorbs gas, its physical properties change, thereby shifting the resonant frequency of the scanning assembly.

Abstract: A display apparatus includes a scanning assembly that scans about two or more axes, typically in a raster pattern. A plurality of light sources emit light from spaced apart locations toward the scanning assembly such that the scanning assembly simultaneously scans more than one of the beams. The scanning assembly is a resonant scanning assembly with a variable resonant frequency. The resonant frequency of the scanning assembly can be actively controlled by controlling partial pressure of fluids in a package containing the scanning assembly. In one embodiment, the increased partial pressure increases the mass of a scanning mirror, thereby changing the resonant frequency. In another embodiment, a gas absorbing material is coupled to a support arm that carries a scanning mirror. As the gas absorbing material absorbs gas, its physical properties change, thereby shifting the resonant frequency of the scanning assembly.

Abstract: A brushless permanent-magnet direct current motor has a permanent magnet which is magnetized to create an offset angle between detent and mutual torques for providing sufficient starting torque for all relative orientations between the stator and the rotor of the motor. This is accomplished by providing a permanent magnet in which the global magnetization of the magnet has been disrupted by the application of a local magnetic field to a portion of the magnet, thereby to provide a magnetic anomaly in the global magnetization. Also, a method of magnetization of the magnet is described.

Abstract: A hydrodynamic bearing is disclosed which includes a shaft and a rotor rotating relative to one another and defining a hydrodynamic bearing in the gap between the relatively rotating parts. Also disclosed is a method for identifying or signaling potential failure of the hydrodynamic bearing. The method for identifying or signaling potential failure includes a capacitance detector for generating a signal representing the capacitance across the gap defining the hydrodynamic bearing, a comparator for comparing the capacitance to an established threshold, and an indicator for providing a signal indicating that operation of the information storage device incorporating the hydrodynamic bearing should continue or that an interruption is likely.

Abstract: A disc drive data storage system according to the present invention comprises a housing, a central axis, a stationary member which is fixed with respect to the housing and coaxial with the central axis, and a rotatable member which is rotatable about the central axis with respect to the stationary member. At least one data storage disc is attached to and is coaxial with the rotatable member. Upper and lower ball bearing assemblies interconnect the stationary member and the rotatable member. At least one rotor magnet is attached to the rotatable member. A back-iron is supported by the stationary member. A stator winding is attached to the back-iron and has a slotless structure.

Abstract: A disc drive for storing and retrieving data from at least one memory storage disc includes a drive base and a spindle motor. The spindle motor includes a rotor hub, a shaft, a bearing unit. The bearing unit rotatably supports the rotor hub about an axis. A controlled resistance electrical pathway is established from the rotor hub to ground to control disc potential and to prevent excess static charge buildup. In one embodiment, the spindle motor includes structural elements made of a conducting plastic having a controlled resistance to establish a controlled resistance electrical pathway from the rotor hub to ground. In a second embodiment, the shaft of the spindle motor includes a conductive contact button electrically connected to the shaft and operatively coupled with a contact shield electrically grounded by an electrical conductor having a controlled resistance.

Abstract: A microprocessor-controlled-circuit applies pulses to a standing motor whose rotor position is to be determined. The time required for the injected current to reach a predetermined threshold in a comparator is measured. The pulses are long enough to effectuate an accurate measurement, but not so long that the rotor moves. The pulse is applied twice to each phase, once with a positive polarity and once with a negative polarity, for a total of six measurements. The positive and negative rise times are subtracted from each other to determine whether the positive or negative current rise time was greater. Based upon the differences in the readings for all of the phases, the position of the rotor is known. There are differences in which the difference is zero or negligible. There are at least two methods to determine rotor position when there are ambiguities in the sign of the difference.

Abstract: A disc drive for storing and retrieving data from at least one memory storage disc includes a drive base and a spindle motor. The spindle motor includes a rotor hub, a shaft, a bearing unit. The bearing unit rotatably supports the rotor hub about an axis. A controlled resistance electrical pathway is established from the rotor hub to ground to control disc potential and to prevent excess static charge buildup. In one embodiment, the spindle motor includes structural elements made of a conducting plastic having a controlled resistance to establish a controlled resistance electrical pathway from the rotor hub to ground. In a second embodiment, the shaft of the spindle motor includes a conductive contact button electrically connected to the shaft and operatively coupled with a contact shield electrically grounded by an electrical conductor having a controlled resistance.

Abstract: An actuator, suited for rapidly and precisely locating the head of a disc drive, reduces variations in flux density and reluctance torque across the entire effective stroke width of the actuator. The actuator, cooperating with a voice coil motor, includes a central yoke, upper and lower yokes aligned above and below the central yoke, and side yokes all formed of magnetic permeable material, a coil movable over the central yoke, and magnets supported from the upper and lower yokes and aligned with the stroke width of the coil. The upper and lower yoke pieces are profiled to have an increased radius in the region near the ends of these yokes and near the end of the coil stroke arc. This maximizes the flux density passing through these yokes so that the flux density and torque applied to the actuator is made linear. The simple structure improves performance without any substantial increase in the design envelope and operates at high efficiency.

Abstract: A voice coil motor (VCM) for a small form factor hard disk drive having a contoured flux field in the air gap wherein adjoining regions of oppositely directed magnetic flux form a transition zone. In the preferred embodiment, the magnetic structure assembly is contoured or shaped. The magnetic structure assembly comprises pole pieces and magnets. The shaping may be of either of the pole pieces or of either of the magnets. The shaping may be along the top edge only, along the bottom edge only, or along both edges. Alternatively, the shaping may be accomplished in the transverse plane, that is by shaping the profile in thickness. The shaping can be done so that when the flux is falling in one gap it is rising in the other gap. In this manner, the sum of the flux in the two gaps remains the same.

Abstract: A spindle motor for rotating at least one disc in a data storage device includes a base, a shaft, a rotor and a stator. A bearing interconnects the rotor with the shaft and allows the rotor to rotate about the shaft. A resilient coupling, such as an O-ring, is compressed between the stator and the base to mechanically isolate the stator from the base and thereby reduce the generation of acoustic noise in the storage device.

Abstract: An apparatus for rotatably journaling a rotor of a spindle motor about a shaft comprising a plurality of annular ring multi-pole magnets, each ring comprised of a plurality of axially aligned magnets whose polarity is alternated along the radius of the ring. The annular ring multi-pole magnets are disposed on both the rotor and stator of a spindle motor in opposition in attraction mode, or a complete offset repulsion mode with like poles facing one another with an full offset, thereby forming a radially stable magnetic bearing for maintaining rotor displacement about a shaft in conjunction with a conventional axial pivot.

Abstract: An apparatus for rotatably journaling a rotor of a spindle motor about a shaft comprising a plurality of annular ring multipole magnets, each ring comprised of a plurality of axially aligned magnets whose polarity is alternated along the radius of the ring. The annular ring multi-pole magnets are disposed on both the rotor and stator of a spindle motor in opposition in attraction mode, or a complete offset repulsion mode with like poles facing one another with an full offset, thereby forming a radially stable magnetic bearing for maintaining rotor displacement about a shaft in conjunction with a conventional axial pivot.

Abstract: A disc drive includes a disc drive motor for rotating a magnetic storage disc. The disc drive includes a sealed disc drive chassis which provides a substantially contaminant-free cavity. A fixed member is coupled to the disc drive chassis and a rotor is rotatably about the fixed member for carrying a magnetic storage disc in the contaminant-free cavity. A bearing assembly between the rotor and fixed member allows rotation of the rotor relative to the fixed member. A gap defined between the rotor and the fixed member separates the bearing assembly from the contaminant-free environment and the magnetic storage disc. A barrier material in the gap has a characteristic which reduces contaminant flow thereby. The barrier material tends to prevent liquid and particulate contaminants from escaping from the drive motor and entering the sealed cavity.

Abstract: Starting of single phase permanent magnet direct current motors in the desired direction of rotation is accomplished by providing a look up table stored in memory giving the correct sign or polarity of current for the angular position of the permanent magnet rotor of the motor. This stored look up table is developed by initially injecting current pulses of opposite polarity at different angular positions of the rotor, determining the difference between the rise times, and mapping the sign and the magnitude of the differences versus angular position. Thereafter, to start the motor in the correct direction, it is only necessary to inject current pulses of opposite polarity to know the angular position of the rotor and the polarity of the current required to start the motor in the correct direction. After the motor has been started, it is commutated by blanking the drive current at the zero crossings of the back emf.

Abstract: An apparatus for rotatably journaling a rotor of a flat spindle motor about a stator comprising a spindle magnet disc disposed on the rotor assembly of the flat spindle motor and journaled about the spindle motor shaft having a disc shaped first magnetized region with an outer radius r comprised of a plurality of axial aligned poles, a disc shaped second region having an outer radius r2 (where r2>r) comprised of a single pole, and a disc shaped non-magnetized spacer region disposed there between. The integrated spindle magnet disc is disposed on the inside surface of a rotor over complementary axially aligned electromagnet poles which are disposed on the base of the stator assembly. A like aligned single pole is fixedly attached to the stator and disposed in opposition to the second magnetized region having like aligned pole of the integrated spindle permanent magnet.

Abstract: A hydrodynamic bearing spindle motor for rotating at least one disc about a central axis in a data storage device comprises a base, a stationary member, a hub, and a stator. A hydrodynamic bearing interconnects the hub with the stationary member such that the hub is rotatable about the central axis. The stator is coaxial with the hub and has at least one stator winding that is distributed about its circumference. The distributed winding attenuates pure tone vibrations which become more noticeable with lower levels of background vibrations in hydrodynamic bearing spindle motors.