Abstract:
An optical recording medium and method for recording/reproducing data on/from the optical recording medium having an optimum recording condition information, are provided. The method includes reading out a reference recording condition recorded on a specific area of the optical recording medium; recording test data while varying a recording condition with respect to the reference recording condition; determining an optimum recording power based on reproduction characteristics of the test data; and recording a recoding condition data including the optimum recording power, recording speed and write strategy type to be used or used to record data, on a specific area of the optical recording medium.

Description:
[0001]    This application is a Continuation of co-pending application Ser. No. 09/664,360, filed on Sep. 18, 2000, and for which priority is claimed under 35 U.S.C. § 120; and this application claims priority of Application No. 40306/1999 filed in Korea on Sep. 18, 1999 under 35 U.S.C. § 119; the entire contents of all are hereby incorporated by reference. 
     
    
     
       BACKGROUND OF THE INVENTION  
         [0002]    1. Field of the Invention  
           [0003]    The present invention relates to an optical recording medium and method for recording or reproducing data on and from the optical recording medium having an optimum recording condition information.  
           [0004]    2. Description of the Conventional Art  
           [0005]    [0005]FIG. 1 illustrates the configuration of an optical recording/reproducing apparatus for recording data on an optical recording medium and reproducing the recorded data.  
           [0006]    As shown in FIG. 1, this optical recording/reproducing apparatus includes a digital recording signal processing unit  30   a  for adding an error correction code (ECC) to input digital data, thereby converting the input digital data into a recording format, a channel bit encoder unit  40  for re-converting the data, converted into the recording format, into a bit stream, an optical driver unit  50  for outputting a light amount drive signal, an optical pick-up unit  11  for recording a desired signal onto an optical recording medium  10  in accordance with the light amount drive signal, and detecting a recording signal from the optical recording medium  10 , and a drive unit  80  for driving the optical pick-up unit  11  and a motor M. The optical recording/reproducing apparatus further includes an R/F unit  60  for filtering a signal detected by the optical pick-up unit  11 , conducting a waveform shaping for the filtered signal, and converting the resultant signal into a binary signal, a serve unit  70  for controlling the driving of the drive unit  80 , based on signals indicative of tracking errors and focusing errors generated in the optical pick-up unit  11 , along with the rotating speed of the optical recording medium  10 , a digital reproduced signal processing unit  30   b  for recovering the binary signal into original data at a clock synchronizing with the binary signal, and a microcomputer  100  for controlling the recording/reproducing procedure.  
           [0007]    Now, an operation of the above mentioned optical recording/reproducing apparatus will be described in conjunction with FIG. 1.  
           [0008]    When a data recording request is inputted to the microcomputer  100  under the condition in which an optical recording medium  10  is loaded in a tray not shown, the optical recording/reproducing apparatus conducts an optimal power calibration (OPC).  
           [0009]    In accordance with the OPC procedure, the microcomputer  100  controls the servo unit  70  and the drive unit  80  prior to recording of input data. In accordance with controlled operations of the servo unit  70  and drive unit  80 , the optical pick-up unit  11  is controlled to read out a target writing power value P ind  recorded in the form of 3-bit data W 1 , W 2 , and W 3 . FIG. 2 illustrates an example of the target writing power value recorded in the form of 3-bit data on the optical recording medium  10 .  
           [0010]    The microcomputer  100  then applies an adjustment signal to the optical driver unit  50  in a variable fashion. The adjustment signal is adapted to vary an optical power with reference to the read target recording power value, for example, 8 mW. FIG. 3 illustrates a variation in optical power with reference to a target recording power value. The optical driver unit  50  outputs a recording signal for test data at an optical drive power corresponding to the adjustment signal. In accordance with the recording signal, the optical pick-up unit  11  records test data onto a test recording area of the optical recording medium  10 . FIG. 4 illustrates a recording signal test area A in a re-writable optical recording medium (CD-RW), along with a count area B for recording the number of test times.  
           [0011]    The microcomputer  100  controls the pick-up unit  11  in a state, in which test data is recorded on the test area A of the optical recording medium  10 , as shown in FIG. 4, in order to sequentially read out test data recorded several times. Each of the test data sequentially read is applied to the R/F unit  60  which, in turn, conducts a filtering and a waveform shaping for the test data, thereby reproducing that test data. FIG. 5 illustrates a reproduced signal for the test data recorded on the optical recording medium.  
           [0012]    The microcomputer  100  then calculates the degree of modulation, based on the reproduced signal, and estimates a polynomial expression for a modulation degree curve (m=f (p)), using a curve filtering.  
           [0013]    The modulation degree m corresponds to a value of I 11T /I TOP  (m=I 11T /I TOP ). Here, “I 11T ” represents the amplitude of the reproduced signal for an 11T signal, and “I TOP ” represents a peak value of the 11T signal.  
           [0014]    Next, a γ curve is derived using the estimated modulation degree curve “m=f(p)”.  
           [0015]    [0015]FIG. 6 illustrates a modulation degree curve “m=f(p)” and a γ curve “γ=g(p)” for detecting an optimum recording power value. Here, an expression “γ=p/m×f′(p)” is established.  
           [0016]    Also, the value of a target γ recorded on the optical recording medium  10  is read out. Based on the read target γ value, an optimum optical power is derived. FIG. 7 illustrates respective data formats of γ and ρ values recorded on the optical recording medium  10 .  
           [0017]    The microcomputer  100  controls the optical driver unit  50  to output, for the input data, a recording signal according to the optimum optical drive power detected in the above mentioned procedure. The optical drive unit  50  applies, to the optical pick-up unit  11 , the recording signal according to the optical drive power, thereby allowing a pulse-width-modulated signal to be recorded onto a program area of the optical recording medium  10 .  
           [0018]    In accordance with a conventional data recording method applied to the above mentioned optical recording/reproducing apparatus, however, the detection of the optimum optical drive power should be conducted using the result of the recording of test data when every data is to be recorded on the optical recording medium. That is, the detection of the optimum optical drive power should be repeatedly conducted for all data to be recorded. For this reason, there is a problem in that the data recording time is delayed.  
           [0019]    In order to solve this problem, the following technique has been proposed.  
           [0020]    That is, the microcomputer  100 , which is a microcomputer internally equipped with a memory, is configured to detect an optimum recording power value based on the recording and reproduction characteristics of test data, as mentioned above, and to record the detected optimum recording power value onto a designated particular area of an optical recording medium  10 , along with an intrinsic recorder identification code for the optical recording/reproducing apparatus previously stored in the memory, that is, information for identifying the optical recording/reproducing apparatus, in order to reserve those information.  
           [0021]    When an optical recording medium  10  is subsequently inserted into the recording/reproducing apparatus for recording of data, the microcomputer  100  reads out an optimum recording power value and an intrinsic recorder identification code from a particular area of an optical recording medium  10 .  
           [0022]    The microcomputer  100  then compares the read intrinsic recorder identification code with the intrinsic recorder identification code of the optical recording/reproducing apparatus. When the microcomputer  100  determines that the read intrinsic recorder ID code corresponds to the intrinsic recorder ID code of the optical recording/reproducing apparatus, it conducts recording of data using an optimum power identified from the optical recording medium  10  without conducting the procedure for detecting an optimum recording power.  
           [0023]    However, where there is no optimum recording power value stored in the optical recording medium  10  or where the intrinsic recorder ID code read out from the optical recording medium  10  does not correspond to the intrinsic code of the recording/reproducing apparatus, the microcomputer  100  conducts the procedure for detecting an optimum recording power, that is, an OPC procedure, because the optimum power value stored in the optical recording medium  10  is that detected and recorded by a recording apparatus other than the above mentioned recording/reproducing apparatus. An optimum recording power value detected in the OPC procedure is then recorded onto the optical recording medium  10 , along with the intrinsic recorder ID code of the recording/reproducing apparatus. Thereafter, desired data is recorded onto the optical recording medium  10  using the optimum power detected in the OPC procedure.  
           [0024]    Thus, it is possible to more or less reduce the data recording time.  
           [0025]    Meanwhile, where recording of data is repeated on a re-writable recording medium in an overwrite fashion, there may be a degradation at side portions of recording marks subjected to an image variation. As a result, a degradation in data recording characteristics may occur. In particular, when the recording apparatus overwrites data at a recording power lower than that used upon the previous data recording, the degradation in data recording characteristics becomes more severe, thereby resulting in increased errors in reproduced signals. FIG. 8 illustrates a relation of the amount of jitters involved in recorded data with respect to the number of data overwrite times. Also, FIG. 9 illustrates a degradation in reproduction characteristics varying depending on a variation in recording power between successive recording procedures.  
           [0026]    The above mentioned problem is also involved in the method using the optimum power value along with the recorder ID code. That is, although recording of data is carried out using the power value derived in accordance with an OPC procedure when the recorder ID code detected from the optical recording medium is different from the identification code of the recording apparatus, it is difficult to expect satisfactory reproduction characteristics when the derived power value is not more than the power value used for the previous data recording, as shown in FIG. 9. The same problem may also occur where recording of data is carried out using the same power as the optimum power value for the data, previously recorded, without the execution of the OPC procedure when the recorder ID code detected from the optical recording medium corresponds to the identification code of the recording apparatus.  
           [0027]    Due to such a degradation in reproduction characteristics, reproduction errors may frequently occur, thereby making it impossible to recover the recorded data.  
         SUMMARY OF THE INVENTION  
         [0028]    Therefore, an object of the invention is to provide a method for recording or reproducing data on or from an optical recording medium, and it comprises the steps of reading out a reference recording condition recorded on a specific area of the optical recording medium; recording test data while varying a recording condition with respect to the reference recording condition; determining an optimum recording power, based on reproduction characteristics of the test data; recording a recoding condition data including the optimum recording power, recording speed and write strategy type to be used or used to record data, on a specific area of the optical recording medium; recording data using the determined optimum recording power; and determining whether to use the recorded recording condition data in next recording mode to record new data.  
           [0029]    Another object of the invention is to provide a method for recording or reproducing data on or from an optical recording medium, and it comprises the steps of reading out a reference recording condition data pre-recorded on an area of the optical recording medium; determining an optimum recording power for a specific recording speed, based on the reference condition data; recording an actual recoding condition data including the optimum recording power for the specific recording speed and a write strategy type for the specific recording speed to be used or used to record data, on a specific area of the optical recording medium; recording data using the determined optimum recording power; recording data at the actual recording speed and using the write strategy type for the specific recording speed; and determining whether to use the recorded actual recording condition data in next recording mode to record new data.  
           [0030]    Another object of the invention is to provide a method for recording or reproducing data on or from an optical recording medium, and it comprises the steps of reading out a reference recording condition data pre-recorded on an area of the optical recording medium; determining an optimum recording power for a specific recording speed, based on the reference condition data; recording an actual recoding condition data including the optimum recording power for the specific recording speed and other recording parameters for the specific recording speed to be used or used to record data, on a specific area of the optical recording medium, wherein the actual recording condition data to be classified by at least different recording speed; recording data using the determined optimum recording power; recording data at the actual recording speed and using other recording parameters for the specific recording speed; and determining whether to use the recorded actual recording condition data in next recording mode to record new data.  
           [0031]    Another object of the invention is to provide a method for recording or reproducing data on or from an optical recording medium, and it comprises the steps of reading out a reference recording condition data pre-recorded on an area of the optical recording medium; determining an optimum recording power for a specific recording speed, based on the reference condition data; and recording an actual recoding condition data including the optimum recording power for the specific recording speed and other recording parameters for the specific recording speed to be used or used to record data, on a specific area of the optical recording medium, wherein the actual recording condition data to be classified by at least one of different recording speed and different recorder ID.  
           [0032]    Another object of the invention is to provide a recording medium, and the recording medium comprises a reference recording condition data recorded on an area of the recording medium; and an actual recoding condition data including an optimum recording power for a specific recording speed and a write strategy type for the specific recording speed to be used or used to record data on a user data area of the recording medium.  
           [0033]    The further object of the invention is to provide a recording medium, and the recording medium comprises a reference recording condition data recorded on an area of the recording medium; and at least two actual recoding condition data classified by at least each different recording speed, each actual recording condition data including an optimum recording power for a specific recording speed and other recording parameters for the specific recording speed to be used or used to record data on a user data area of the recording medium. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0034]    The above objects, and other features and advantages of the present invention will become more apparent after a reading of the following detailed description when taken in conjunction with the drawings, in which:  
         [0035]    [0035]FIG. 1 is a block diagram illustrating the configuration of a general optical recording/reproducing apparatus;  
         [0036]    [0036]FIG. 2 is a diagram illustrating the data format for a reference power value recorded on a re-writable optical recording medium;  
         [0037]    [0037]FIG. 3 is a graph illustrating a variation in optical power with reference to a reference recording power value in the recording of test data;  
         [0038]    [0038]FIG. 4 is a view illustrating a recording signal test area A in a re-writable optical recording medium, along with a count area B for recording the number of test times;  
         [0039]    [0039]FIG. 5 is a waveform diagram illustrating a reproduced signal for the test data recorded on the optical recording medium;  
         [0040]    [0040]FIG. 6 is a graph depicting a modulation degree curve and a γ curve for detecting an optimum recording power value;  
         [0041]    [0041]FIG. 7 is a diagram illustrating respective data formats for γ and β values recorded on the optical recording medium;  
         [0042]    [0042]FIG. 8 is a graph illustrating a variation in jitter depending on the number of data overwrite times;  
         [0043]    [0043]FIG. 9 is a table illustrating a variation in the reproduction characteristics of the optical recording medium depending on a variation in recording power value;  
         [0044]    [0044]FIG. 10 is a flow chart illustrating an optimal recording method for optical recording media in accordance with a preferred embodiment of the present invention;  
         [0045]    [0045]FIG. 11 is a diagram illustrating optimum recording condition information recorded on the count area of the optical recording medium in accordance with the present invention;  
         [0046]    [0046]FIG. 12 is a flow chart illustrating an optimal recording method for optical recording media in accordance with another embodiment of the present invention;  
         [0047]    [0047]FIG. 13 is a table illustrating various optimum power values for optical recording/reproducing apparatuses of different types respectively;  
         [0048]    [0048]FIG. 14 is a diagram illustrating respective formats of TOC information and optimum recording condition information recorded on the lead-in area of the optical recording medium; and  
         [0049]    [0049]FIG. 15 is a diagram illustrating respective lead-in areas of sessions in an optical recording medium, each lead-in area being recorded with optimum recording condition information. 
     
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0050]    Now, preferred embodiments of an optimal recording method for optical recording media in accordance with the present invention will be described.  
         [0051]    The optical recording/reproducing apparatus illustrated in FIG. 1 may be used to implement the optimal recording method for optical recording media in accordance with the present invention. The optimal recording method of the present invention is characterized by additionally recording information about optimum recording conditions, detected by the execution of a procedure for detecting an optimum recording power value, on a count area B or a lead-in area of an optical recording medium  10 , and subsequently determining, based on the optimum recording condition information, whether or not a procedure for detecting an optical recording power value is to be conducted. Sequential procedures of the optimal recording method according to the present invention are executed under the control of the microcomputer  100  shown in FIG. 1.  
         [0052]    [0052]FIG. 10 is a flow chart illustrating an example of the optimum recording method for optical recording media according to the present invention.  
         [0053]    In accordance with the present invention, the count area B of an optical recording medium  10  is defined to be written with information about optimum recording conditions detected in the above mentioned procedure for detecting an optimum recording power value in association with an optical recording medium. This optimum recording condition information additionally recorded is used for data to be subsequently recorded.  
         [0054]    In accordance with this optimum recording method, the microcomputer  100  determines at first step S 10  whether or not an optical recording medium is loaded in the optical recording/reproducing apparatus. When it is determined that an optical recording medium is loaded in the optical recording/reproducing apparatus, it is determined at step S 20  whether or not a request for data recording is made. Where it is determined at step S 20  that there is a data recording request, the microcomputer  100  reads a count area B included in a PCA area (FIG. 4) of the optical recording medium  10  in order to determine whether or not there is recording condition information on the count area B (Step S 21 ).  
         [0055]    Thereafter, the microcomputer  100  determines whether or not there is recording condition information on the count area B (Step S 30 ). Where there is no recording condition information on the count area B, the microcomputer  100  conducts a procedure for detecting an optimum recording power value for the optical recording medium  10  because this state corresponds to a state in which there is no data recorded on the program area of the optical recording medium  10 .  
         [0056]    In order to execute the power detecting procedure, the control procedure of the microcomputer  100  proceeds to step S 32 . At step S 32 , the microcomputer  100  records test data onto the test area A of the optical recording medium  10 , and then detects an optimum recording power value, based on the result of the recording of the test data. This power detecting procedure is conducted in the same fashion as the above mentioned conventional method.  
         [0057]    When an optimum recording power value is detected for the optical recording medium  10  in accordance with the execution of step S 32 , the microcomputer  100  generates information about optimum recording conditions including the detected optimum recording power value. This optimum recording condition information is recorded onto the count area B of the optical recording medium  10  (Step S 33 ).  
         [0058]    Here, the optimum recording condition information is information adapted to determine whether or not the procedure for detecting an optimum recording power value is to be conducted for recording of data. Referring to FIG. 11, such optimum recording condition information is illustrated. As shown in FIG. 11, the optimum recording condition information consists of 42-bit data including 4-bit sync data, 3-bit optimum power data indicative of the detected power value, a 12-bit RID code indicative of a recorder ID stored in a memory internally equipped in the microcomputer  100 , 4-bit record speed data indicative of the current recording speed, 3-bit write strategy indicative of write strategy type, 2-bit reserved data, and 14-bit CRC data for error check, to be used or used to record data.  
         [0059]    In addition to the 42-bit optimum recording condition information, null data may be written on the remaining area of the 1ATIP (1 Absolute Time In Pre-groove) frame. In order to obtain an enhanced reliability, the optimum recording condition information may also be repeatedly recorded within the length of the 1 ATIP frame.  
         [0060]    After completing the optimum power detecting and recording procedures as described above, the microcomputer  100  controls the optical driver unit  50  to record input digital data onto the program area of the optical recording medium  10  starting from an initial position of the program area, using an optical drive current corresponding to the recorded power value (Step S 34 ).  
         [0061]    Now, a description will be made in conjunction with the case in which it is determined at step S 30  that there is data recorded on the count area B, and the recording request at step S 20  is not associated with overwriting of data, that is, the case in which data is written on the program area at a position following the initial position.  
         [0062]    In this case, the microcomputer  100  identifies the information recorded on the count area. B of the optical recording medium  10 , that is, information for determining whether or not the optimum recording power value detecting procedure is to be conducted.  
         [0063]    To this end, the microcomputer  100  compares the recorder ID code, included in the optimum recording condition information, with the ID code of the optical recording/reproducing apparatus stored in the internal memory of the microcomputer  100 , at step S 31 .  
         [0064]    Based on the result of the comparison, the microcomputer  100  determines whether or not the recorder ID code of the optical recording/reproducing apparatus corresponds to the recorder ID code detected from the optical recording medium (Step S 40 ). Where the ID cods are identical to each other, the microcomputer  100  then compares the current record speed with a record speed detected from the optical recording medium (Step S 41 ). Based on the result of the comparison, the microcomputer  100  determines whether or not the two record speeds are identical to each other (Step S 50 ).  
         [0065]    When it is determined at step S 50  that the current record speed corresponds to the record speed detected from the optical recording medium, this means that the optical recording medium  10  has been recorded with data, at least one time, at the same record speed as the current record speed, using the present optical recording/reproducing apparatus. In this state, accordingly, the microcomputer  100  identifies an optimum recording power value from the optimum recording condition information including the same record speed information as the current record speed information, without conducting the procedure for detecting an optimum power value at the data recording request (Step S 51 ).  
         [0066]    Since the identified power value is an optimum power value suitable for the optical system and circuit characteristics of the present optical recording/reproducing apparatus, the microcomputer  100  conducts recording of data on the optical recording medium  10 , using the identified power value (Step S 52 ).  
         [0067]    However, where it is determined at step S 40  that the two recorder ID codes are different from each other or where it is determined at step S 50  that the two recode speeds are different from each other, the control procedure of the microcomputer  100  proceeds to step S 32 . At step  32 , the microcomputer  100  executes the above mentioned optimum power value detecting procedure. Following step S 32 , the microcomputer  100  executes procedures for generating and recording information about optimum recording conditions (Steps S 33  and S 34 ).  
         [0068]    Here, the case, in which there is a difference between the optical recording medium  10  and the optical recording/reproducing apparatus in terms of the recorder ID code or the recode speed information, corresponds to the case in which there is no occasion that the optical recording medium has been recorded with data, using the optical recording/reproducing apparatus.  
         [0069]    This case may also correspond to the case in which the optimum recording condition information written on the optical recording medium  10  has been updated or deleted, on the basis of a determination for the optimum recording condition information to be useful no longer.  
         [0070]    Also, this case may correspond to the case in which although a data recording operation has been conducted for the optical recording medium  10  by the optical recording/reproducing apparatus, its record speed is different from the current record speed.  
         [0071]    In this case, accordingly, the procedures for detecting an optimum power value, generating information about optimum recording conditions, and recording the optimum recording condition information are carried out (Steps S 32 , S 33 , and S 34 ).  
         [0072]    [0072]FIG. 12 illustrates another embodiment of the optimal recording method for optical recording media according to the present invention.  
         [0073]    The optimal recording method of FIG. 12 is associated with the case in which the recording request at step S 20  of FIG. 11 corresponds to a data overwrite request.  
         [0074]    In this case, the microcomputer  100  conducts, in response to the recording request, a control procedure to directly execute a data overwrite operation without determining whether or not the procedure for detecting an optimum recording power value based on the optimum recording condition information written on the count area B of the optical recording medium is to be carried out.  
         [0075]    In accordance with this optimal recording method of FIG. 12, the microcomputer  100  first determines whether or not an optical recording medium is loaded in the optical recording/reproducing apparatus (Step S 60 ). When it is determined that an optical recording medium is loaded in the optical recording/reproducing apparatus, it is determined whether or not a request for data recording made corresponds to a data overwrite request (Step S 70 ). Where the data recording request corresponds to a data overwrite request, the microcomputer  100  identifies a highest power value from the recording condition information written on the count area B of the optical recording medium  10  (Step  71 ). Using the identified highest power value, the microcomputer  100  overwrites data on the optical recording medium  10  (Step S 72 ).  
         [0076]    This procedure is adapted to avoid a degradation in the characteristics of record signals occurring when overwriting of data is conducted at an optical power less than that used in the previous data recording.  
         [0077]    After completing the data overwrite operation, the microcomputer  100  completely deletes the recording condition information written on the count area B of the optical recording medium  10  (Step S 73 ). The reason why the recording condition information written on the count area B of the optical recording medium  10  is to be completely deleted will now be described.  
         [0078]    For example, it is assumed that the optical recording medium  10  is recorded with various optimum power values for optical recording/reproducing apparatuses A, B, and C of different types respectively, as shown in FIG. 13.  
         [0079]    Where the above mentioned procedure is carried out in this case, overwriting of data is conducted at a highest power value, that is, the power value of 9.5 mV associated with the optical recording/reproducing apparatus C. When data is recorded using the optical recording/reproducing apparatus B under the condition in which the optimum recording condition information of FIG. 13 is still maintained, a degradation in reproduction characteristics may occur because the power value of 8 mV less than the power value used in the previous data recording is used. In order to avoid this problem, the recording condition information written on the count area of the recording medium is completely deleted.  
         [0080]    At step S 74 , the microcomputer  100  then generates again recording condition information including the identified recording power value, the current record speed, and the recorder ID code stored in the internal memory of the microcomputer  100 . The generated recording condition information is then written on the initial portion of the count area B.  
         [0081]    Alternatively, the optimum recording condition information may be recorded on respective lead-in areas of sessions in the case of a multi-session type optical recording medium.  
         [0082]    In this case, once an optimum recording power value is detected in accordance with the optimum recording power detecting procedure, that is, the OPC procedure, as mentioned above, desired data is recorded onto a track at the detected power value. After the recording of data, a session completion is made for that track. Thereafter, optimum recording condition information is written on the lead-in area of an associated session in the form of sub-queue data having a format of FIG. 14. At this time, the address of an address field for the optimum recording condition information is designated by a value other than values, previously designated, for example, values of “1” or “5”. For example, the address value may be a value of “2”. This value of “2” is recorded as a value indicative of the optimum recording condition information. Accordingly, it can be found that when the address value of an address field detected corresponds to “2”, data following the address data is optimum recording condition information having the same format as that of FIG. 11.  
         [0083]    In accordance with such a recording procedure, optimum data recording condition information will be recorded for every session on the optical recording medium. FIG. 15 illustrates the recording format of an optical recording medium recorded with optimum recording condition information for every session. As shown in FIG. 15, optimum recording condition information is written on the lead-in area of each session.  
         [0084]    Where an optical recording medium recorded with data for every session is loaded in the optical recording/reproducing apparatus A in order to record data thereon, and when a request for overwriting data on a particular session is made, the microcomputer of the optical recording/reproducing apparatus A detects an optimum recording power value from the optimum recording condition information written on the lead-in area of the particular session designated for the data overwriting.  
         [0085]    For example, if the detected optimum recording power value is 10 mW different from that of the present optical recording/reproducing apparatus A, this optical recording/reproducing apparatus A does not record data at the detected power value of 10 mV. In this case, the optical recording/reproducing apparatus A derives an optimum recording power value for the optical recording/reproducing apparatus A corresponding to the detected optimum recording power value of 10 mW. Where data is recorded on an optical recording medium using an optical recording/reproducing apparatus at an optimum recording power value detected by another optical recording/reproducing apparatus, the recording of data may be practically carried out at a power value more or less than the optimum recording power value used for the optical recording medium because respective optical driver units of those optical recording/reproducing apparatuses may have different offset values. In order to avoid such a situation, an optimum recording power value is derived based on the detected optimum recording power value, as mentioned above.  
         [0086]    Also, where data is overwritten on the optical recording medium at a power value more than the power value used in the previous data recording, a degradation in reproduction characteristics may occur. Although a reduction in jitter occurs for a certain number of overwrite times, as indicated by an interval “C” in FIG. 8, a sharp increase in jitter exceeding an allowable range occurs following the interval “C”. In order to avoid such a situation, it is avoided to overwrite data at a power value more than the power value used in the previous data recording.  
         [0087]    In order to derive an optimum recording power value for the present optical recording/reproducing apparatus A corresponding to the detected optimum recording power value used for the previous data recording, the microcomputer of the optical recording/reproducing apparatus A conducts the above mentioned OPC procedure, thereby deriving a modulation degree curve as shown in FIG. 6. Thereafter, the microcomputer reproduces data from a session designated for the data overwriting, thereby deriving a degree of modulation for a particular signal component, for example, an 11T component. A recording power value corresponding to the degree of modulation associated with the session to be overwritten with data is derived from the modulation degree curve derived in the OPC procedure. The derived recording power value is the recording power value for the present optical recording/reproducing apparatus A corresponding to 10 mW, that is, the optimum recording power value for the optical recording/reproducing apparatus used in the previous data recording. The microcomputer of the optical recording/reproducing apparatus A overwrites input data onto the designated session at the derived power value.  
         [0088]    Although the optical recording/reproducing apparatus A records data onto the optical recording medium at a recording power value identical to the previous power value, it may achieve the recording of data in a different fashion by deriving an optimum recording power value in accordance with an OPC procedure, comparing the derived power value with the recording power value used for the previous data recording, and overwriting input data at the derived recording power value when the derived recording power value is not less than the previous recording power value.  
         [0089]    It is desirable for this method to be conducted in the case in which there is a high possibility of a degradation in the reproduction characteristics of overwritten data occurring, when the overwriting of data is conducted using a recording power value used in a previous data recording, due to a considerable difference of the recording power value from a desired optimum recording power value.  
         [0090]    As apparent from the above description, the present invention provides an optimal recording method for optical recording media which is capable of additionally recording information about optimum recording conditions on the count area or lead-in area of an optical recording medium in order to allow a subsequent recording of data on the optical recording medium, using an optimum recording power value included in the recorded optimum recording condition information.  
         [0091]    Therefore, in accordance with the present invention, it is possible to prevent a degradation in the reproduction characteristics of overwritten data from occurring when the power value used in the overwriting of the data is less than the power value used in the previous data recording.  
         [0092]    Although the preferred embodiments of the invention have been disclosed for illustrative purposes, those skilled in the art will appreciate that various modifications, additions and substitutions are possible, without departing from the scope and spirit of the invention as disclosed in the accompanying claims.