Device for reading from or writing to recording media in disc form exhibiting unbalance

Abstract

The present invention relates to a device for reading from or writing to recording media in disc form which has an unbalance compensation means. The object of the invention is to propose a device of this type which has the smallest possible unbalance even when exchangeable recording media are used. This object is achieved according to the invention by virtue of the fact that the unbalance compensation means is a centrifugal force generation means which generates a centrifugal force which is variable during operation. According to another aspect of the present invention, provision is made for the unbalance compensation means to be a positioning means for positioning the recording medium. The field of application of the invention includes, inter alia, devices for reading from and/or writing to optical recording media such as CD, CD-ROM, DVD, DVD-ROM, DVD-RAM and the like.

What is claimed is:  
     
         1 ) Device for reading from or writing to recording media in disc form having a drive motor, a securing means and an unbalance compensation means, characterized in that the unbalance compensation means is a centrifugal force generation means with a centrifugal force which is variable during operation.  
     
     
         2 ) Device according to  claim 1 , characterized in that the centrifugal force generation means has a mass element, which can be moved during operation.  
     
     
         3 ) Device according to  claim 2 , characterized in that two mass elements are arranged such that they can move about the axis of rotation of the recording medium.  
     
     
         4 ) Device according to  claim 2 , characterized in that a plurality of small mass elements are present which can be placed along a circumference or a radius of the centrifugal force generation means.  
     
     
         5 ) Device according to  claim 4 , characterized in that an adhesion element or a holding element is arranged on the circumference or on the radius of the centrifugal force generation means.  
     
     
         6 ) Device according to  claim 1 , characterized in that the unbalance compensation means has a control means, which essentially follows the rotary movement of the unbalance compensation means.  
     
     
         7 ) Device according to  claim 6 , characterized in that the control means is a lever element.  
     
     
         8 ) Device according to  claim 7 , characterized in that the lever element has a point of action on a rotating part, a point of action on a stationary part and a point of action on a mass element.  
     
     
         9 ) Device according to  claim 1 , characterized in that the unbalance compensation means has a control means which is arranged such that it is essentially stationary with respect to the device.  
     
     
         10 ) Device according to  claim 9 , characterized in that the stationary control means has a braking means, which influences the angular position or the radial position of the mass element.  
     
     
         11 ) Device according to  claim 10 , characterized in that the unbalance compensation means has a positioning gear mechanism with rotating elements which can be influenced by the braking means.  
     
     
         12 ) Device according to  claim 10 , characterized in that the braking means is part of an engagement means for the recording medium.  
     
     
         13 ) Device according to  claim 9 , characterized in that the control means has a long-range-force-generating element.  
     
     
         14 ) Device according to  claim 13 , characterized in that the mass element is a magnetizable mass element and the long-range-force-generating element is a magnet.  
     
     
         15 ) Device according to  claim 1 , characterized in that a sensor and an evaluation means are present.  
     
     
         16 ) Device according to  claim 15 , characterized in that the sensor is a vibration sensor.  
     
     
         17 ) Device according to  claim 1 , characterized in that the unbalance compensation means has a sensor element, an evaluation means and a centrifugal force generation means or a positioning means, which are all arranged on a rotating part of the device.  
     
     
         18 ) Device for reading from or writing to recording media in disc form having a drive motor, a securing means and an unbalance compensation means, characterized in that the unbalance compensation means is a positioning means for positioning the recording medium.  
     
     
         19 ) Device according to  claim 18 , characterized in that the positioning means has spring elements and damper elements, which are arranged such that they are distributed uniformly over the circumference of the said positioning means.  
     
     
         20 ) Device according to  claim 18 , characterized in that a sensor and an evaluation means are present.  
     
     
         21 ) Device according to  claim 20 , characterized in that the sensor is a vibration sensor.  
     
     
         22 ) Device according to  claim 18 , characterized in that the unbalance compensation means has a sensor element, an evaluation means and a centrifugal force generation means or a positioning means, which are all arranged on a rotating part of the device.  
     
     
         23 ) Device for reading from or writing to recording media in disc form having a drive motor, a securing means and an unbalance compensation means, characterized in that the unbalance compensation means is an additional force generation means, which has, in particular, a long-range force generation means.  
     
     
         24 ) Device according to  claim 23 , characterized in that the long-range force generation means has a magnetic field generation means.  
     
     
         25 ) Device according to  claim 24 , characterized in that the magnetic field generation means is integrated in the drive motor.  
     
     
         26 ) Device according to  claim 23 , characterized in that a sensor and an evaluation means are present.  
     
     
         27 ) Device according to  claim 26 , characterized in that the sensor is a vibration sensor.  
     
     
         28 ) Method for setting a variable centrifugal force of a centrifugal force generation means, having the following steps: 
 a) start of the setting procedure,    b) comparison of a measured value, which corresponds to an unbalance, with a lower limit value and branching to step o) if the measured value lies below the limit value,    c) storage of the present value as stored value,    e) changing of the angular position of the mass element by a first value,    f) comparison of a present measured value (U n ) with the stored value, and branching to step h) if the present value is less than the stored value,    g) changing of the angular position of the mass element by a second value, whose sign and magnitude do not correspond to those of the first value from step e),    h) comparison of the difference between present value and stored value with a threshold value and branching to step c) if the threshold value is exceeded,    j) storage of the present value as stored value,    k) changing of the moment of inertia of the mass element by a first value,    l) comparison of a present measured value with the stored value and branching to step n) if the present value is less than the stored value,    m) changing of the moment of inertia of the mass element by a second value, whose sign and magnitude do not correspond to those of the first value from step k),    n) comparison of the difference between present value and stored value with a lower limit value and branching to step j) if the limit value is exceeded,    o) end of the setting procedure.    
     
     
         29 ) Method according to  claim 28 , characterized in that the following step is carried out between steps c) and e): 
 d) addition of a mass element.