Rotary drive for a data carrier

Abstract

A data medium is driven by a brushless direct current more, and possesses control signals en a track which can be picked up by a sensing device and supplied to a switch arrangement for activation of the motor winding. The control signals on the track characterize at least those angular positions of the rotor with respect to the stator in which commutation is to be initiated.

I claim:  
     
       1. A rotary drive for rotating a  an optical data carrier, comprising a brushless direct current motor with a permanent magnet rotor;  and a wound stator having at least one winding coil; 
       a circuit arrangement for activation the winding coil to generate a magnetic field for producing rotary movement in the rotor;  
       optical sensing means for reading signals recorded on the optical data carrier, the output of the optical sensing means being connected to the circuit arrangement for activating the winding, and the optical data carrier having control signals which identify at least those angular positions of the rotor relative to the stator at which commutation of current fed to the winding cod is to the initiated.  
     
     
       2. A drive as claimed in  claim 1 , wherein the optical data carrier has first and second control signals for each commutation angular position and the circuit arrangement can be induced to activate the winding by a first control signal to interrupt the fed correct to the winding coil currently being energized, and by a subsequent second control signal for switching the current through an the next winding coil in an energizing sequence. 
     
     
       3. A drive n claimed in  claim 1 , further comprising delay means in the circuit arrangement and wherein, on receipt of a control signal supplied by the optical sensing means, the circuit arrangement for activating the winding interrupts the fed current to the energized winding coil, the delay means in the circuit arrangement is activated and, on the expiry of a delay time, the correct is switched through to the cast winding coil in an energizing sequence. 
     
     
       4. A drive n claimed in  claim 1 , wherein at least two circumferentially spaced control signals for each commutation angular position are provided on the optical data carrier, and the circuit arrangement further comprises a measuring device to determine the chronological interval between the two spaced control signals which follow, each other as the optical data carrier rotates, the measurement result of which measuring device is evaluated to control the magnitude of the current to be fed to the winding. 
     
     
       5. A drive as claimed in  claim 6  wherein the circuit arrangement further includes a comparator to determine the deviation from a preset value, and a delay device with varying or variable delay times, wherein a delay time of a magnitude commensurate the deviation from the present value can be initiated by the circuit arrangement between the interruption of the fed current to the energized winding coil and energization of the next winding coil in an energizing sequence. 
     
     
       6. A drive a claimed in  claim 4  wherein the circuit arrangement further includes a comparator to determine the deviation from a preset value, wherein in accordance with the deviation from the preset value, the circuit arrangement switches through a current pulse of increased or decreased current pulse breadth to the next winding coil in an energizing sequence. 
     
     
       7. A drive as claimed in any one of the preceding claims   claim 1 , wherein the optical sensing means includes respective optical write/read heads for the motor control signals and for the data signals to be written onto or read from the optical data carrier. 
     
     
       8. A drive as claimed in any our of claims  1 - 6   7 , wherein one control signals are located on a concentric storage track of the optical data carrier. 
     
     
       9. A drive as claimed in  claim 8 , wherein the storage track is a radially outer track of the optical data carrier. 
     
     
       10. A data storage device, comprising: 
       
         a non-magnetic movable data storage medium;  
       
       
         a brushless direct current motor with a permanent magnet rotor and a wound stator having at least one winding coil for conducting current pulses to generate a magnetic field for producing rotary movement of the rotor;  
       
       
         a data sensing means for reading data signals recorded on the data storage medium, the data signals including control data signals which identify at least those angular positions of the rotor relative to the stator at which commutation of current pulses conducted by the winding coil is to be initiated, said control data signals remaining in permanently fixed angular locations on said data storage medium relative to said rotor; and  
       
       
         a circuit operating to feed current pulses to said winding coil to rotate said rotor and to produce and separate the current pulses in response to said control data signals read from said data storage medium, said circuit being connected to the output of said data sensing means. 
       
     
     
       11. The data storage device of  claim 10 , wherein the data storage medium has first and second control signals for each commutation angular position and the circuit arrangement can be induced to activate the winding by a first control signal to interrupt the fed current to the winding coil currently being energized and by a subsequent second control signal for switching the current through to the next winding coil in an energizing sequence. 
     
     
       12. The data storage device of  claim 10 , further comprising delay means in the circuit and wherein, on receipt of a control signal supplied by the sensing means the circuit for activating the winding interrupts the fed current to the energized winding coil the delay means in the circuit is activated and, on the expiry of a delay time, the current is switched through to the next winding coil in an energizing sequence. 
     
     
       13. The data storage device of  claim 10 , wherein at least two circumferentially spaced control data signals for each commutation angular position are provided on the data storage medium, and the circuit further comprises a measuring device to determine the chronological interval between the two spaced control data signals which follow each other as the data storage medium rotates, the measurement result of which measuring device is evaluated to control the magnitude of the current to be fed to the winding. 
     
     
       14. The data storage device of  claim 13 , wherein the circuit further includes a comparator to determine the deviation from a preset value, and a delay device with varying or variable delay times, wherein a delay time of a magnitude commensurate with the deviation from the preset value can be initiated by the circuit between the interruption of the fed current to the energized winding coil and energization of the next winding coil in an energizing sequence. 
     
     
       15. The data storage device of  claim 13 , wherein the circuit further includes a comparator to determine the deviation from a preset value, wherein in accordance with the deviation from the preset value, the circuit switches through a current pulse of increased or decreased current pulse breadth to the next winding coil in an energizing sequence. 
     
     
       16. The data storage device of  claim 10 , wherein the sensing means includes respective read/write heads for the motor control data signals and for the data signals to be written onto or read from the data storage medium. 
     
     
       17. The data storage device of claims  10 ,  11 ,  12 ,  13 ,  14 ,  15 , or  16 , wherein the control data signals are located on a concentric storage track of the data storage medium. 
     
     
       18. The data storage device of  claim 17 , wherein the storage track is a radially outer track of the data storage medium.