Abstract:
An apparatus for controlling an erasing power level, which is capable of optimally setting a power level applied to a disc when erasing a test period in an OPC (Optimum Power Control) area of the disc, and a method using the apparatus. The apparatus includes: a pickup unit irradiating light corresponding to the erasing power level to a test period and receiving reflected light; an RF processing unit outputting an indication signal indicating a writing state of the test period according to an output of the pickup unit; and a control unit temporarily setting a plurality of erasing power levels, erasing the test period by applying the plurality of erasing power levels, and then setting any one of the plurality of erasing power levels to an optimum erasing power level on the basis of the indication signal.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS  
       [0001]     This application claims the benefit of Korean Patent Application No. 2005-85895, filed Sep. 14, 2005 in the Korean Intellectual Property Office, the disclosure of which is incorporated herein by reference.  
       BACKGROUND OF THE INVENTION  
       [0002]     1. Field of the Invention  
         [0003]     Aspects of the invention relate to an apparatus for controlling an erasing power level and a method using the same, and more particularly to an apparatus for controlling an erasing power level, which is capable of optimally setting a power level applied to a disc when erasing a test period in an OPC (Optimum Power Control) area of the disc, and a method using the same.  
         [0004]     2. Description of the Related Art  
         [0005]     In a high-density disc, such as a Blu-ray disc rewritable (BD-RE), a distance between tracks is very short. Thus, if a writing power level is improper, a cross-talk and a cross-erase can occur when performing a reproducing operation and a recording operation. In consideration of the cross-talk and cross-erase, an OPC (optimum power control) operation has been performed in order to suitably select the writing power level applied to the disc.  
         [0006]     The procedure for performing the OPC operation is as follows. To begin with, a test period in an OPC area of the disc is erased to be initialized. Next, a specific writing power pattern is formed in a part of the erased test period. Thus, by checking a state of the writing power pattern, an optimum writing power level is defined. However, since a firstly-used disc does not perform the OPC operation, it is difficult to set a power level for erasing the test period.  
         [0007]     On the other hand, a disc manufacturer defines a range of the recommended erasing power level, wherein the recommended erasing power level is applied to the disc when erasing the test period. When erasing the test period according to the recommended erasing power level of the disc manufacturer, it is possible to ensure an adequate test period. However, if a deviation occurs with respect to a laser diode constituting a pickup unit, even though the recommended erasing power level of the disc manufacturer is applied to the disc, the erasing power level can be substantially improper, and thereby the writing power level typically can not be optimally set.  
       SUMMARY OF THE INVENTION  
       [0008]     Therefore, it is an aspect of the invention to provide an apparatus for controlling an erasing power level which is capable of optimally setting an erasing power level for erasing a test period of a rewritable disc, and a method using the same.  
         [0009]     In accordance with the invention, the above and/or other aspects can be achieved by the provision of an apparatus for controlling an erasing power level for erasing a test period arranged in an OPC (optimum power control) area of a rewritable disc, the apparatus including a pickup unit to irradiate light corresponding to the erasing power level to the test period and to receive reflected light; an RF processing unit to output an indication signal indicating a writing state or an erased state of the test period according to an output of the pickup unit; and a control unit for temporarily setting a plurality of erasing power levels, erasing the test period by applying the plurality of erasing power levels, and then setting any one of the plurality of erasing power levels to an optimum erasing power level on the basis of the indication signal.  
         [0010]     In other aspects of the invention, the apparatus can further include a memory to store information in relation to the optimum erasing power level set through the control unit. Also, the control unit can store the information in relation to the optimum erasing power level in the disc through the pickup unit. Further, the control unit can set the recommended erasing power level with respect to the disc to a temporary erasing power level.  
         [0011]     In accordance with another aspect of the invention, there is provided a method of controlling an erasing power level for erasing a test period arranged in an OPC area of a rewritable disc, the method including: determining whether information in relation to an optimum erasing power level to erase the test period is pre-stored; temporarily setting a plurality of erasing power levels when the information is pre-stored according the determination result; and setting any one of the plurality of erasing power levels to an optimum erasing power level according to a state of the test period, wherein the test period is firstly erased by applying the plurality of erasing power levels.  
         [0012]     In other aspects of the invention, the control unit, when the information in relation to an optimum erasing power level is pre-stored according the determination result, can erase the test period by applying the pre-stored optimum erasing power level. Also, temporarily setting a plurality of erasing power levels can be performed by adding or subtracting a predetermined value to/from the recommended erasing power level. Further, the setting of any one of the plurality of erasing power levels to an optimum erasing power level can further include: erasing the test period by applying the optimum erasing power; determining whether a state of the erased test period is satisfied; and re-setting the optimum erasing power level when the state is not satisfied according to the determination result.  
         [0013]     Additional aspects and/or advantages of the invention will be set forth in part in the description which follows and, in part, will be obvious from the description, or may be learned by practice of the invention. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0014]     These and/or other aspects and advantages of the invention will become apparent and more readily appreciated from the following description of the embodiments, taken in conjunction with the accompanying drawings of which:  
         [0015]      FIG. 1  is a view showing the configuration of rewritable disc, such as a Blu-ray disc rewritable (BD-RE), as an example of a disc to which aspects of the invention can apply;  
         [0016]      FIG. 2A  is a view illustrating a test period in an OPC area of the disc of  FIG. 1 ;  
         [0017]      FIG. 2B  is a view illustrating an erasing power level for erasing a test period;  
         [0018]      FIG. 2C  is a table illustrating recommended erasing power levels of various disc manufacturers;  
         [0019]      FIG. 3A  is a view illustrating an operation for erasing a test period to which aspects of the invention can be applied;  
         [0020]      FIG. 3B  is a view illustrating an operation to form a writing power pattern in an erased test period to which aspects of the invention can be applied;  
         [0021]      FIG. 4A  is a view showing a test period erased using a low erasing power level to which aspects of the invention can be applied;  
         [0022]      FIG. 4B  is a view showing a test period erased using an adequate erasing power level to which aspects of the invention can be applied;  
         [0023]      FIG. 4C  is a view showing a test period erased using an excessive erasing power level to which aspects of the invention can be applied;  
         [0024]      FIG. 5  is a block diagram showing the configuration of an apparatus for controlling an erasing power level according to an aspect of the invention; and  
         [0025]      FIGS. 6A and 6B  are flowcharts illustrating a method for controlling an erasing power level according to an aspect of the invention. 
     
    
     DETAILED DESCRIPTION OF THE EMBODIMENTS  
       [0026]     Reference will now be made in detail to the embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein like reference numerals refer to the like elements throughout. The embodiments are described below in order to explain the present invention by referring to the figures.  
         [0027]      FIG. 1  is a view showing the configuration of a rewritable disc  200 , such as a high density optical disc or a Blu-ray disc rewritable (BD-RE). As shown in  FIG. 1 , the high-density optical disc  200 , for example, a Blu-ray disc rewritable (BD-RE), has a track structure which is includes an inner area  210 , a center area  220 , and a rim area  230 , wherein, the inner area  210  of the disc  200  includes a Clamping Area  211 , a Transition Area  212 , a BCA (Burst Cutting Area)  213  and a Lead-In Zone  214 . In addition, the center area  220  and the rim area  230  of the disc  200  include a Data Zone  222  and a Lead-Out Zone  232 , respectively.  
         [0028]     Continuing with reference to the disc  200  of  FIG. 1 , the Lead-In Zone  214  is divided and allocated into a first protection zone (Protection Zone  1 )  214   a , a PIC (Permanent Information and Control data) area  214   b , a second protection zone (Protection Zone  2 )  214   c , a second information area (INFO  2 )  214   d , an OPC (Optimum Power Control) area  214   e , a reserved area  214   f  and a first information area (INFO  1 )  214   g . The first protection zone (Protection Zone  1 )  214   a  and the PIC (Permanent Information and Control data) area  214   b  are pre-recorded areas in which data are pre-recorded, while the remaining areas of the Lead-In Zone  214 , the Data Zone  222  and the Lead-Out Zone  232  are rewritable areas in which new data are rewritten.  
         [0029]     Also, with respect to the disc  200  of  FIG. 1 , the BCA (Burst Cutting Area)  213  is an inner most area for being firstly accessed when loading the disc  200 , such as a BD-RE disc, in the recording/reproducing apparatus, wherein various disc information such as a disc serial number (DSC), encryption information for disk copy protection, that is, Copy Protection Information (CPI), and the like, are recorded in the BCA  213 . The PIC area  214   b  is an area in which general disc information to be permanently preserved is stored, and wherein a High Frequency Modulated (HFM) groove is recorded in the PIC area  214   b . The OPC area  214   e  is an area arranged in the Lead-In Zone  214 , which is used when performing an OPC operation to select an optimum writing power level which can be different according to each manufacturer. An example of a PM address of the OPC area  214   e  is 0x1bc00˜0x1dc00.  
         [0030]      FIG. 2A  is a view illustrating a test period in an OPC area  214   e  of the disc  200  of  FIG. 1 , and  FIG. 2B  is a view illustrating an erasing power level for erasing a test period. Referring to  FIG. 2A , a part of the OPC area  214   e  is defined as a test period (EP). The test period (EP) is divided into a first period (EP 1 ), a second period (EP 2 ) and a third period (EP 3 ), wherein the writing power pattern is formed in the second period (EP 2 ). Whether the writing power pattern is pre-recorded in the test period (EP) or not, a process for erasing the whole test period is typically required so as to initialize the test period (EP). This is referred to as initialization of the test period. At this time, the power level for erasing the test period (EP) is referred as an erasing power level. The erasing power level is also referred as a DC power level (Pdc) since it has a fixed power level, such as shown in  FIG. 2B .  
         [0031]      FIG. 2C  is a table illustrating recommended erasing power levels of various disc manufacturers A, B and C. In addition, a disc manufacturer typically recommends a range of the adequate erasing power level. As shown in  FIG. 2C , the erasing power levels (PW 1 , PW 2  and PW 3 ) recommended, or predetermined, by the various disc manufacturers (A, B and C) can be different. For example, sizes of the erasing power levels can be PW 1 &lt;PW 2 &lt;PW 3 .  
         [0032]      FIG. 3A  is a view illustrating an operation for erasing a test period for a disc  200  as can be applied in an aspect of the invention. For example, as shown in  FIG. 3A , the initialization of the test period is an operation for erasing the first to third periods (EP 1 , EP 2  and EP 3 ) among the test period (EP) by applying the first erasing power level (PW 1 ).  
         [0033]      FIG. 3B  is a view illustrating an operation for forming a writing power pattern in an erased test period for a disc  200  as can be applied in an aspect of the invention. After the initialization of the test period (EP), a writing power pattern (Popc) is formed in the second period (EP 2 ) of the test period (EP) as shown in  FIG. 3B . This writing power pattern (Popc) is formed by varying the writing power level for every specific period. Because the writing power pattern (Popc) is formed in the initialized test period, when the initialization process is improperly performed, it can have a negative effect upon setting the optimum writing power level using the writing power pattern.  
         [0034]      FIG. 4A  is a view showing a test period erased using a low erasing power level,  FIG. 4B  is a view showing a test period erased using an adequate erasing power level, and  FIG. 4C  is a view showing a test period erased using an excessive erasing power level for a disc  200  as can be applied in aspects of the invention.  
         [0035]     For example, as shown in  FIG. 4A , in order to erase the test period (EP), when applying an erasing power level (PW 11 ) which is below an adequate level value of the erasing power, the data pre-recorded in the test period (EP) which are not completely erased can remain. In this case, when the writing power pattern is formed in a second period (EP 12 ), it can be difficult to ensure the setting of the optimum writing power level due to the remaining data.  
         [0036]     As shown in  FIG. 4B , when applying an erasing power level (PW 12 ) which is of an adequate level of the erasing power, the data pre-recorded in the test period (EP 22 ) can be completely erased. In this case, when the writing power pattern is formed in a second period (EP 22 ), it is possible to promote ensuring the setting of the optimum writing power level.  
         [0037]     In addition, as shown in  FIG. 4C , when applying an excessive erasing power level (PW 13 ) which exceeds the adequate level of the erasing power, the remaining data can be completely erased. However, since the erasing power level is too high, it can cause physical characteristics of the test period to be excessively changed. In this case, when the writing power pattern is formed in a second period (EP 23 ), it can be difficult to ensure the setting of the optimum writing power level due to physical characteristics of which can be excessively changed.  
         [0038]     Thus, as shown in  FIG. 4B , the disc manufacturers typically recommend use of the adequate erasing power level in consideration of disc characteristics and a disc type. However, the recommended erasing power level of the disc manufacturer does not always coincide in the optimum erasing power level which is suitable to initialize the test period due to a deviation of a laser diode in the pickup unit, etc.  
         [0039]     In consideration of the above and/or other aspects of the invention, an apparatus for controlling an erasing power level according to an embodiment of the present invention sets various temporary erasing power levels including the recommended erasing power level of a disc, such as recommended, or predetermined, by the manufacturer of the disc or other predetermined or pre-stored erasing power level for the disc. Next, the apparatus erases the test period according to one or more of the temporary erasing power levels, selects the best, or optimum, erasing power level among the temporary erasing power levels, and sets the erasing power level to the optimum erasing power level. In addition, the apparatus according an embodiment of the present invention stores information in relation to the optimum erasing power level in a storage medium or a disc. Thereafter, the apparatus according to the present invention retrieves the stored information, and applies the retrieved information when erasing the test period.  
         [0040]      FIG. 5  is a block diagram showing the configuration of an apparatus  1  for controlling an erasing power level according to an embodiment of the present invention. As shown in  FIG. 5 , the apparatus  1  for controlling an erasing power level according to an embodiment of the present invention includes a pickup unit  20 , an RF processing unit  30 , a signal processing unit  40 , a control unit  50  and a memory  60 .  
         [0041]     In the apparatus of  FIG. 5 , the pickup unit  20  reproduces data from a high-density disc  10 , such as the disc  200  of  FIG. 1  or a Blu-ray disc rewritable (BD-RE), and records data on the disc  10 . The RF processing unit  30  receives an output signal of the pickup unit  20 , sets a wave-form of the output signal, and transmits the output signal to the signal processing unit  40 . The signal processing unit  40  receives an output signal from the RF processing unit  30 , and performs a signal processing operation such as a decoding operation, and the like, under control of the control unit  50 , such as a microprocessor or an application specific integrated circuit (ASIC), with associated memory and software or programming, for controlling operation of the apparatus  1  including determining and controlling an erasing power level for erasing a test period for a rewritable disc, such as the disc  10 . The memory  60 , associated with the control unit  50 , serves to store various types of information under control of the control unit  50  for operation of the apparatus  1 , including information for determining and controlling an erasing power level for erasing a test period for a rewritable disc, such as the disc  10 .  
         [0042]     Continuing with reference to  FIG. 5 , in order to perform the OPC operation, the control unit  50  outputs a power level set signal (Pset) to set the power level to the pickup unit  20 . Accordingly, the pickup unit  20  sets a power level of the laser diode of the pickup unit  20  according to a temporary erasing power level, irradiates a laser beam corresponding to the power level into the disc  10 , receives a reflected beam from the disc  10 , and transmits a signal corresponding to the reflected beam to the RF processing unit  30 . The RF processing unit  30  then outputs an RECD signal to the control unit  50 , wherein the RECD signal is a signal to indicate to record corresponding data in a specific area of the disc  10 . The control unit  50  recognizes a record state of the test period according to a state of the RECD signal (High or Low logical value).  
         [0043]     The control unit  50  then performs an operation for erasing the test period by applying the temporary erasing power level or levels, and checks the record state of the test period. In addition, the control unit  50  sets the best, or optimum, erasing power level according to the check result of the record state of the test period. Herein, the best, or optimum, erasing power level is referred to as an erasing power level suitable to the disc  10 , such as shown in  FIG. 4B .  
         [0044]     A method of controlling an erasing power level according to an aspect of the present invention will now be explained with reference to  FIGS. 6A and 6B , and with reference to  FIGS. 1 through 5 .  FIGS. 6A and 6B  are flowcharts illustrating a method of controlling the erasing power level according to an aspect of the present invention.  
         [0045]     In  FIG. 6A , the control unit  50 , to begin, sets an operation mode for performing the OPC (operation  101 ) when loading the disc  10 , such as the disc  200 , in the recording/reproducing apparatus  1 , and the control unit  50  proceeds with a series of subsequent procedures according to the operation mode. The control unit  50  determines whether a writing start command for performing the OPC is received (operation  103 ). When the writing start command is received, the control unit  50  retrieves data stored in the memory  60  or the disc  10 , or in both (operation  105 ).  
         [0046]     According to the result retrieved in operation  105 , the control unit  50  determines whether a pre-stored optimum erasing power level (Pe) exists in the memory  60  or the disc  10  (operation  107 ). When the pre-stored optimum erasing power level (Pe) does not exist, the control unit  50  sets the test period (EP) in the OPC area  214   e  as shown in  FIG. 2A  (operation  109 ). As illustrated in  FIG. 2A , the test period (EP) is divided into the first period (EP 1 ), the second period (EP 2 ) and the third period (EP 3 ). Next, the control unit  50  retrieves a recommended erasing power level (Pdc), such as illustrated in  FIGS. 2B and 2C , applicable to the loaded disc  10  through the memory  60  or the disc  10  (operation  111 ), and sets a plurality of temporary erasing power levels including the retrieved recommended erasing power level (Pdc) (operation  113 ). The number of the temporary erasing power levels does not need to be defined, and can be set or determined as needed. For example, the temporary erasing power levels can be set to small or large values as a specific value (for example, 0.3 mW to 1 mW) on the basis of the recommended erasing power level. According to an embodiment of the present invention, the number of the temporary erasing power levels can be set in the range of 3 to 6. For example, when the recommended erasing power level is 4 mW, the temporary erasing power level or levels can be set to 3.5 mW, 4 mW, 4.5 mW, or other appropriate value or values for the temporary erasing power level or levels.  
         [0047]     In order to erase the test period by applying the preset temporary erasing power level or levels, the control unit  50  transmits a power level set signal (Pset) to the pickup unit  20 . Thus, the pickup unit  20  irradiates the laser beam corresponding to the preset temporary erasing power level, and erases the first, second and/or third periods (EP 1 , EP 2  and/or EP 3 ) of the test period (EP) (operation  115 ). At this time, the RF processing unit  30  provides the RECD signal to the control unit  50 , and the control unit  50  checks the RECD signal in the erased test period (operation  117 ) to determine an erased state of the test period (EP).  
         [0048]     Next, the control unit  50  determines whether the operation for erasing the respective test period with respect to the temporary erasing power level or levels is completed (operation  119 ). According to the determination result as to whether the operation for erasing the respective test period is completed, when the determination result indicates the operation for erasing the test period is not completed, the process returns to operation  115 . When the determination result in operation  119  indicates that the operation for erasing the test period is completed, the control unit  50  selects the best, or optimum, erasing power level on the basis of the check result of the RECD signal for the temporary erasing power level or levels, and sets the erasing power level to the optimum erasing power level (Pe) (operation  121 ). At this time, the control unit  50  stores information in relation to the optimum erasing power level (Pe) in the memory  60  or the disc  10 , or in both the memory  60  and the disc  10 .  
         [0049]     The control unit  50  erases the test period by communicating with the pickup unit  20  to apply the optimum erasing power level (Pe) (operation  123 ). The control unit  50  then sets or can set a test period different from the above-set test period for controlling an erasing power level for erasing the different test period.  
         [0050]     On the other hand, according to the determination result in operation  107 , when the pre-stored optimum erasing power level (Pe) is present in the memory  60  or the disc  10 , the control unit  50  erases the test period using the pre-stored optimum erasing power level (operation  108 ).  
         [0051]     In addition, when erasing the test period by applying the optimum erasing power level in operation  108  or operation  123 , the control unit  50  checks the erased state of the test period according to the RECD signal (operation  125 ). According to the check result of the erased state of the test period according to the RECD signal, the control unit  50  determines whether the erased state is satisfied (operation  127 ). If the erased state is not satisfied, the process returns to operation  109  in order to re-set the optimum erasing power level.  
         [0052]     According to the determination result of whether the erased state is satisfied in operation  127 , when the erased state is satisfied, as shown in  FIG. 3B , the control unit  50  forms through the pickup unit  20  the writing power pattern (Popc) in the second period (EP 2 ) of the test period (operation  129 ). In addition, the control unit  50  checks the record state of the test period, such as the second period (EP 2 ), according to the RECD signal to determine a writing state of the test period, and determines and sets the optimum writing power level, such as by varying the writing power level, or selectively applying one or a plurality of writing power levels to form the writing power pattern (Popc), and then determining, according to the RECD signal, the writing state of the test period corresponding to the applied writing power level, to determine whether the applied writing power level is the optimum writing power level (operation  131 ), which can then be stored in the memory  60  or in the disc  10 .  
         [0053]     From the above description, an aspect of the present invention provides an apparatus for controlling an erasing power level, wherein, by setting various temporary erasing power levels, selecting the best, or optimum, erasing power level among the temporary erasing power levels, and setting the erasing power level to the optimum erasing power level, it is possible to set the optimum erasing power level without having a negative influence due to the deviation of the laser diode in the pickup unit, etc., and, in another aspect of the invention, to provide a method of controlling an erasing power level using such apparatus.  
         [0054]     In addition, another aspect of the present invention provides an apparatus for controlling an erasing power level, wherein, the apparatus erases the test period by applying the optimum erasing power level for a disc, such as a rewritable disc, suitable to an actual recording/reproducing apparatus, and sets the optimum erasing power level from a writing power pattern formed in the test period, thereby promoting ensuring increased reliability with respect to the writing power level, and a method of controlling an erasing power level using such apparatus.  
         [0055]     In addition, further aspects of the present invention provide an apparatus for controlling an erasing power level and a method for controlling an erasing power level using such apparatus, wherein, with respect to a disc, such as a rewritable disc, in which a recording/reproducing apparatus does not perceive a pre-stored or predetermined optimum erasing power level for the disc provided from a disc manufacturer, since such apparatus and method sets the best, or optimum, erasing power level among a plurality of temporary erasing power levels, it is possible to use various discs with the recording/reproducing apparatus.  
         [0056]     The foregoing embodiments, aspects and advantages are merely exemplary and are not to be construed as limiting the present invention. Also, the description of the embodiments of the present invention is intended to be illustrative, and not to limit the scope of the claims, and various other alternatives, modifications, and variations will be apparent to those skilled in the art. Therefore, although a few embodiments of the present invention have been shown and described, it would be appreciated by those skilled in the art that changes may be made in the embodiments without departing from the principles and spirit of the invention, the scope of which is defined in the claims and their equivalents.