Patent Publication Number: US-5155719-A

Title: Optical information recording and/or reproducing apparatus

Description:
BACKGROUND OF THE INVENTION 
     Field of the Invention and Related Art Statement 
     The present invention relates to an optical information recording and/or reproducing apparatus comprising an optical means for projecting a light beam upon an optical record medium, and a driving means for driving the optical record medium with respect to an optical axis of the optical means to effect the information recording and/or reproduction. 
     Optical record media can be roughly classified into read-only type, write-once type and rewritable type. Each of these different types of record media includes a large sub-varieties whose characteristics are different from each other based upon construction, materials, etc. of each optical record medium. 
     In order to effect recording and/or reproduction accurately for different optical record media, it is necessary to adjust the power of a laser light beam which is made incident upon the record medium to an optimum value. 
     In Japanese Patent Application Laid-open Publication Kokai Sho No. 63-103446, there is disclosed an optical information recording and/or reproducing apparatus in which the writing power of the laser light is adjusted in accordance with identifying information provided on a carriage of a record medium, i.e. an optical disk. That is to say, the above information is directly written on the cartridge surface or a label having the information written thereon is applied on the cartridge surface. In Japanese Patent Application Laid-open Publication Kokai Sho No. 63-108539, there is described another known optical information recording and/or reproducing apparatus comprising a detector for reproducing the information recorded on a magnetic tape which is applied on the cartridge of a disk and the writing laser power is controlled in accordance with the information reproduced from the magnetic tape. 
     In the known optical information recording and/or reproducing apparatuses mentioned above, the operational condition data such as the optimum writing laser power, writing pulse duration and reading, laser power have been recorded on the cartridge of the record medium. Usually the record medium and the cartridge are manufactured separately, so that there might occur that the record medium denoted by the information recorded on the cartridge is not always identical with the actual record medium installed in the cartridge. Moreover, the information recorded on the cartridge is liable to be damaged and stained, and thus the information could not be reproduced correctly. 
     Further in the write-once type and rewritable type optical record media, there has been proposed to record the information about the optimum laser power, etc. in a control track of an optical record medium in accordance with a proposal (DP9171, DP10089) of ISO (International Organization for Standardization). The operational condition data recorded in the record medium is first read out and the writing laser power is set to the optimum value in accordance therewith. It should be noted that the operational condition may also include the optimum laser power for reading and optimum time durations of recording pulses. 
     In the above explained known optical information recording and/or reproducing apparatus, the operational condition data such as the optimum writing laser power, optimum reading laser power, writing pulse duration, etc. is recorded. These values are usually selected when the record medium is set on the standard apparatus. However, in practice, the optical information recording and/or reproducing apparatuses have different characteristics, so that the optimum operational conditions for the standard apparatus could not be suitable for particular apparatuses. The optical information recording and/or reproducing apparatuses have optical systems having different NA, laser light source (different wavelengths) and the methods of measuring the laser power are different from each other. Particularly, when optical information recording and/or reproducing apparatuses which use the same optical record medium are manufactured by different makers, the optimum operational conditions differ from each other. 
     SUMMARY OF THE INVENTION 
     The present invention has for its object to provide a novel and useful optical information recording and/or reproducing apparatus in which the recording and/or reproducing can be carried out always accurately for various kinds of optical information record mediums. 
     According to the invention, an optical information recording and/or reproducing apparatus comprises 
     an optical means for projecting a light beam upon an optical record medium; 
     a driving means for driving the optical record medium with respect to an optical axis of the optical means; 
     a memory means for storing plural sets of operational condition data for plural kinds of optical information record media to be used in the apparatus; 
     a detecting means for reading information recorded on a control track of an optical information record, medium set on the apparatus and for identifying the kind of optical information record medium in accordance with the detected information; and 
     a control means for reading a set of operational condition data out of said memory means in accordance with the identified kind of the optical record medium and controlling the recording and/or reproducing operation in accordance with the read out operational condition data. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a schematic view showing an embodiment of the optical information recording and/or reproducing apparatus according to the invention; 
     FIG. 2 is a flow chart representing the operation of the apparatus shown in FIG. 1; and 
     FIG. 3 is a flow chart explaining a modification of the operation of the apparatus according to the invention. 
    
    
     DETAILED EXPLANATION OF THE PREFERRED EMBODIMENTS 
     FIG. 1 is a schematic view illustrating an embodiment of the optical information recording and/or reproducing apparatus according to the invention. In the present embodiment, an optical information record disk 1 is set on the apparatus and is rotated by a spindle motor 2 and information recorded in a control track of the optical disk is read out with the aid of an optical pick-up 3. Then, a kind of the optical disk 1 is identified by an identifying unit 4 in accordance with the read out information. A signal representing the detected kind of the optical disc 1 is supplied to a memory unit 5 as an address signal. In the memory unit 5 there have been previously stored plural sets of operational condition data for particular optical disks which are used by the present apparatus. A set of operational condition data related to the relevant optical disk 1 is read out of the memory unit 5 in accordance with the address signal supplied from the identifying unit 4. The operational condition data thus read out is supplied to a control unit 6 including a CPU. The control unit 6 controls operations of various units of the apparatus in accordance with the operational condition data. That is to say, a laser power of laser light emitted by a laser light source provided in the optical pick-up unit 3 is controlled by means of D/A converter 7 and laser driving circuit 8 in accordance with the recording or reproducing operation mode. 
     In accordance with ISO standard proposal, 4 bytes from 14 bytes to 17 bytes in the control track of the optical disk are not specified and are used as a vender unique area. Usually in this vender unique area there is recorded a name of a manufacture of the disk in ASCII code and when a manufacture makes a plurality of kinds of optical disks, identifying data for identifying a kind of the optical disk is also recorded. In the present embodiment, the kind of the optical disk is identified by utilizing such data stored in the vender unique area of the optical disk. 
     In the memory unit 5 there have been previously stored plural sets of operational condition data which have been obtained by actually using respective optical disks. For instance, optimum laser power for recording the information, optimum recording pulse widths in dependence on the disk rotating mode (CAV or CLV) and optimum laser power for reading the information out of the optical disk have been derived experimentally and have been stored in the memory unit 5. These plural sets of operational condition data are stored in the memory unit 5 in such a manner that they can be retrieved in accordance with the address signal corresponding to the identifying data read out of the optical disk. 
     An example of the operational condition data stored in the memory unit 5 is shown in the following table. In this example, optimum recording laser power and recording pulse width are defined for four different optical disks which are rotated in the CAV (constant angular velocity) mode. 
     
                       TABLE                                                       
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         Optimum Re-                                                      
Identifying                                                               
         cording Power                                                    
                     Pulse Width (nsec)                                   
Information                                                               
         (mW)        Inner     Middle                                     
                                     Outer                                
______________________________________                                    
ABCD     8           60        80    100                                  
ZAB1     7.5         70        90    110                                  
CCC1     8.5         90        90    100                                  
CCC2     7.5         90        90    110                                  
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     In the above table, four byte identifying information denote the name of the manufacture who made the optical disks and have been recorded in the vender unique area of the control track in ASCII code. CCC1 and CCC2 represent two different kinds of optical disks manufactured by the same disk maker. 
     Now the operation of the present embodiment will be explained with reference to a flow chart shown in FIG. 2. 
     At first, the optical disk 1 is set on a turntable and is rotated by the spindle motor 2. Then, the focusing and tracking servo control is turned on to read the information recorded in the control track of the optical disk 11. The read out information is supplied to the identifying unit 4. On the basis of the read out information, it is judged whether or not the optical disk is one corresponding to ISO. When the optical disk 1 is one corresponding to ISO, then the information recorded in the vender unique area of the control track is extracted and it is judged whether or not the relevant optical disk has been registered. That is to say, it is checked whether or not the operational condition data for the relevant optical disk has been stored in the memory unit 5. 
     When it is confirmed that the optical disk 1 does not correspond to ISO or the operational condition data of the optical disk has not been stored in the memory unit 5, it is difficult to effect the recording and/or reproducing accurately, so that the optical disk 1 is ejected. 
     Contrary to this, when it is confirmed that the optical disk 1 corresponds to ISO and the operational condition data of the optical disk has been stored in the memory unit 5, the operational condition data is read out of the memory unit 5 and the read out data is supplied to the control unit 6. Then the control unit 6 controls the recording and/or reproducing operation in accordance with the read out operational condition data. That is to say, in the recording mode, the recording power of the laser light is set to the optimum value denoted by the operational condition data by means of the D/A converter 7 and laser driving circuit 8. 
     As explained above, in the present embodiment a plurality of sets of the operational condition data for various kinds of optical record disks have been experimentally derived by using the actual optical disks and have been stored in the memory unit 5, and the information recorded in the vender unique area of the control track of the optical disk is read out to identify the optical disk. Then a corresponding set of operational condition data is selectively read out of the memory unit 5, and the various units of the apparatus are controlled in accordance with the thus read out operational condition data. Therefore, an optimum recording and reproducing operation can be always achieved. 
     The present invention is not limited to the embodiment explained above, but may be modified in various ways. For instance, in the above embodiment the optical disk is checked to determine whether it corresponds to ISO. However, according to the invention it is not always necessary to effect this check. In this case, the contents of the memory unit 5 may be retrieved in accordance with the identifying information as illustrated in FIG. 3. Further, in the above embodiment the optical record disk is identified in accordance with the information recorded in the vender unique area in the control track of the optical disk, but the identification may be effected by reading information recorded in another data area in the control track or the whole data in the control track. Further in the above embodiment, the optical record medium is an optical disk, but it may be formed by an optical record card. Moreover, the present invention may be applied not only to the once-write type and rewritable type record medium, but also to the read-only type record medium. 
     As explained above, in the optical information recording and/or reproducing apparatus according to the present invention, a plurality of sets of operational condition data for various kinds of optical record mediums have been experimentally derived by using the actual optical record media and have been stored in the memory unit, and the information recorded in the control track of the optical record medium is read out to identify the optical record medium set on the apparatus. Then, a corresponding set of operational condition data is selectively read out of the memory unit, and the various units of the apparatus are controlled in accordance with the thus read out operational condition data. Therefore, an optimum recording and/or reproducing operation can be always performed accurately.