Abstract:
An optical information recording method and an apparatus that is capable of forming recording marks having the same length on a land and a groove track of an optical recording medium. The optical information recording method and apparatus identify whether any one of a land and a groove track on an optical recording medium is accessed. Then, the optical information recording method and apparatus establish differently an outputting manner of recording lights to be irradiated on the optical recording medium on the basis of a detecting resultant of the land and groove tracks.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     This invention relates to a method and an apparatus for recording an information on an optical recording medium having land and groove tracks. 
     2. Description of the Related Art 
     Nowadays, a need of larger capacity has been increased in an optical recording/reproducing field or an opto-magnetic recording/reproducing field in order to record an information that is greatly enlarged in the quantity. Accordingly, in optical discs such as a DVD-RAM (digital versatile disc-random access memory) and so on, there has been suggested so-called a land/groove recording system having an information recorded on both of land and groove tracks. Actually, a disc of a phase-change recording system such as DVD-RAM and a disc of an opto-magnetic recording system such as ASMO (Advanced Storage Magneto-Optical) are known as the disc of land/groove recording system. 
     Referring to FIGS. 1 and 2, there are shown an optical recording medium  20  having land tracks  22  and groove tracks  24 . The optical recording medium  20  consists of an information recording and reproducing layer  26 , a reflective layer  28  and a protective layer  32  formed sequentially under a substrate  30 . The information recording and reproducing layer  26  records an information and the reflective layer  28  reflects a light beam. The substrate  30  and the protective layer  32  are formed by a material hating relatively low heat conductivity. For example, PMMA (Poly Methyl MethAcrylate) can be used as the substrate material and the protective layer  32  can be formed by a resin class. Meanwhile, the information recording and reproducing layer  26  and the reflective layer  28  are formed by the material having a relatively high heat conductivity. The information recording and reproducing layer  26  can consist of a recording layer  26   a , a reproduction supporting layer  26   b  and a reproducing layer  26   c , as shown in FIG.  3 . The recording layer  26   a  and the reproduction supporting layer  26   b  are formed by a TbFeCo and a GdFe, respectively. The reproducing layer  26   c  and the reflective layer  28  are made of a GdFeCo and a Al, respectively. 
     In such an optical recording medium as described above, the information recording and reproducing layer  26  positioned at the land track  22  lies adjacent to the materials having the high heat conductivity. Meanwhile, the information recording and reproducing layer  26  positioned at the groove track  24  is contiguous to the materials having a low heat conductivity. Accordingly, the land and groove tracks  22  and  24  have a different thermal conductivity when a light beam is irradiated on the optical recording medium  20 . As a result, a thermal characteristic difference appears between the land and groove tracks  22  and  24 . 
     The thermal characteristic difference allows recording pits formed on the land and groove tracks  22  and  24  to have a different length although the light beam of the same recording power is irradiated on the optical recording medium with the land and groove tracks  22  and  24 . In detail, the material on the areas adjacent to the land track  22  radiates a great amount of thermal energies when the light beam is irradiated on the land track  22 . This results from that the material on the area adjacent to the land track  22  has the high heat conductivity. Thus, a relatively short recording pits are formed on the information recording and reproducing layer  26  corresponding to the land track  22 . Meanwhile, the material on the areas adjacent to the groove track  24  radiates a small amount of thermal energies when the light beam is irradiated on the groove track  24 . This results from that the material on the area adjacent to the groove track  24  has the low heat conductivity. Therefore, a relatively long recording pits are formed on the information recording and reproducing layer  26  corresponding to the land track  24 . In other words, although the light beam having the same recording power is irradiated on the land and groove tracks  22  and  24 , the recording pits formed on the land and groove tracks  22  and  24  have a different length according to the widths of the land and groove tracks  22  and  24  and the depth from the land track  22  to the groove track  24 . Due to this, recording errors can be generated when the information is recorded on the optical recording medium. 
     Further, the recording errors can increase more and more as the capacity of the opical recording mdeium is enlarged. This results from the tact that the difference between the recording pits on the land and groove tracks  22  and  24  is enlarged in accordance with decreasing of the land and groove tracks  22  and  24  in width. 
     SUMMARY OF THE INVENTION 
     Accordingly, it is an object of the present invention to provide an optical information recording method and an apparatus that can form recording marks having the same length on a land and a groove track of an optical recording medium. 
     In order to achieve these and other objects of the invention, an optical information recording method according to an aspect of the present invention includes the steps of: identifying whether any one of a land and a groove track on an optical recording medium is accessed; and establishing differently an outputting manner of recording lights to be irradiated on the optical recording medium on the basis of a identifying resultant for the land and groove tracks. 
     An optical information recording method according to another aspect of the present invention allows a rotating speed of optical recording medium to be different depending on a land/groove identification signal for indicating a land and a groove track on the optical recording medium. 
     An optical information recording apparatus according to still another aspect of the present invention includes: distinguishing means for identifying whether any one of a land and a groove track is accessed; and recording means for establishing differently an outputting manner of recording lights to be irradiated on the optical recording medium on the basis of an identifying resultant of the distinguishing means and for performing a recording operation. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     These and other objects of the invention will be apparent from the following detailed description of the embodiments of the present invention with reference to the accompanying drawings, in which; 
     FIG. 1 is a schematic view showing an optical recording medium having a structure of land and groove; 
     FIG. 2 is a sectional view showing the structure of the optical recording medium in FIG. 1; 
     FIG. 3 is a sectional view showing in detail the information recording layer and the reproduction layer in FIG. 2; 
     FIG. 4 is a schematic block diagram showing the configuration of an optical information recording apparatus according to an embodiment of the present invention; 
     FIG. 5 is a characteristic view showing temperature profiles on a land and a groove when light beams having the same power level are respectively irradiated on the land and the groove; 
     FIG. 6 a characteristic view explaining temperature profiles on a disc in accordance with a duty rate of pulse when an information is recorded by a laser pulse train on the disc; and 
     FIG. 7 a characteristic view depicting temperature profiles on a land and a groove in accordance with a rotation speed of disc. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Referring to FIG. 4, there is shown a optical information recording apparatus according to an embodiment of the present invention. The optical information apparatus of FIG. 4 has an optical pickup  40  for recording a data on a optical recording medium  20  and reproducing the data from the optical medium  20 , a control signal detector  50  for detecting a control signal from an electrical signal generated at the optical pickup  40 , and a land/groove distinguishing stage  60  for identifying a land/groove track on the basis of the control signal from the control signal detector  50 . Also, the optical information apparatus includes a signal processor  80  for converting a recording data into a channel bit stream (hereinafter, CHBS), a controller  110  for controlling the circuits of the optical recording apparatus in accordance with a land/groove identification signal from the land/groove distinguishing stage  60 , and a LD (Laser Diode) driver  70  for driving a LD included in the optical pickup  40  according to the CHBS from the signal processor  80  and controlling a record power of light beam on the basis of a control signal from the controller  110 . The signal processor  80  converts the recording data into the CHBS and applies the CHBS to the LD driver  70 . The LD driver  70  responds to the CHBS to switch the LD of the optical pickup  40 . The optical pickup  40  irradiates the light beam on a land track  22  and a groove track  24  of the optical recording medium  20  as shown in FIG. 1, to form recording marks corresponding to the recording data. The land track  22  has the temperature profile different from that of the groove track  24  in the case that the light beams having the same recording power are irradiated on the land and groove tracks  22  and  24 , as show in FIG.  5 . In FIG. 5, a curve  1  represents a temperature profile on the groove track  24  when the light beam is irradiated on the groove track  24 . Another curse  3  shows a temperature profile on the land track  22  when the light beam is irradiated on the land track  22 . The temperature profile difference between the land and groove tracks  22  and  24  for the light beam having the same recording power results from that the land track  22  has a heat conductivity different from that of the groove track  24 . Due to this, the record marks formed on the land and groove tracks  22  and  24  are different from each other in length. To solve this problem, the optical information recording apparatus according to an embodiment of the present invention sets up differently the intensities of the light beams to be irradiated on the land and groove tracks  22  and  24  such that the temperature profile on the land track  22  is equal to that of the groove track  24 . Therefore, the marks formed on the land and groove tracks  22  and  24  by the optical information recording apparatus according to an embodiment of the present invention have the same length. 
     In order to set up the intensity of the light beam in accordance with the land and groove tracks  22  and  24 , the optical information recording apparatus according to an embodiment of the present invention employs the land/groove distinguishing stage  60  for identifying whether the track accessed by the optical pickup  40  is the land track  22  or the groove track  24  The procedure for identifying of the land and groove tracks  22  and  24  will be described in detail. The optical pickup  40  irradiates the light beam on the optical recording medium  20  and converts the quantity of the lights reflected by the optical recording medium  20  into an electrical signal. The control signal detector  50  detects a tracking error signal from the electrical signal generated at the optical pickup  40  and applies the tracking error signal to the land/groove distinguishing stage  60 . Then, the control signal detector  50  inverts the polarity of the tracking error signal in accordance with whether the track accessed by the optical pickup  40  is the land track  22  or the groove track  24 . The land/groove distinguishing stage  60  identifies the land/groove track on the basis of the tracking error signal and applies a land/groove identification signal to the controller  110 . The controller  110  responds to the land/groove identification signal and supplies a control signal corresponding to the land track  22  or the groove track  24  to the LD driver  70 . Thus, the LD driver  70  responds to the control signal from the controller  110  and adjusts the intensity of the light beam to be generated at the optical pickup  40 , thereby allowing the intensities of the land track  22  to be the same to that of the groove track  24 . 
     The method for adjusting the intensity of the light beam sets up the intensity of the light beam irradiated on the groove track  24  lower than that of the light beam irradiated on the land track  22 . If the land/groove distinguishing stage  60  identifies that the groove track  24  has been accessed, the controller  110  controls the LD driver  70  to have the power level lower than a previously established power level, thereby forming the recording marks corresponding to the CHBS on the groove track  24  by a light beam of low power level. Meanwhile, when the land/groove distinguishing stage  60  identifies that the land track  22  has been accessed, the controller  110  enables the LD driver  70  to maintain the previously established power level so as to form the recording marks corresponding to the CHBS on the land track  22  by a light beam of high power level. In this case, the power level of the light beam irradiated on the groove track must be set up appropriately such that the recording marks formed on the land and groove tracks  22  and  24  are the same to each other in length. 
     On the other hand, the recording marks formed on the land and groove tracks  22  and  24  identifies each other in length by adjusting the duty ratio of the light beam in accordance with the land and groove tracks  22  and  24 . In detail, the controller  110  controls the LD driver  70  to have the pulse duty ratio lower than a previously established pulse duty ratio when the land/groove distinguishing stage  60  identifies that the groove track  24  has been accessed, thereby forming the recording marks corresponding to the CHBS on the groove track  24  by a light beam pulse of low duty ratio. Meanwhile, if the land/groove distinguishing stage  60  identifies that the land track  22  has been accessed, the controller  110  enables the LD driver  70  to maintain the previously established pulse duty ratio so as to form the recording marks corresponding to the CHBS on the land track  22  by a light beam pulse of high duty ratio. In this case, the duty ratio of the light beam pulse irradiated on the groove track  22  must be set up appropriately such that the recording marks formed on the land and groove tracks  22  and  24  are the same to each other in length, FIG. 6 shows temperature profiles on the land and groove tracks  22  and  24  in accordance with the duty ratio of the light beam pulse. In FIG. 6, a curse  5  represents a temperature profile on the track when the light beam pulse is set up at low duty ratio. Another curse  7  shows a temperature profile on the track in the case that the light beam pulse has a middle duty ratio. Still another curse  9  depicts a temperature profile on the track when the duty ratio of the light beam pulse is high. Wherein, the temperature on the track occupied by a spot of the light beam becomes high relatively to the duty ratio of the light beam pulse. In other words, the temperature on the track occupied by the spot of the light beam is high when the duty ratio of the light beam pulse is established at a high value, while is low in the case that the light beam pulse has a duty ratio of low value. In this case, the duty ratio of the light beam irradiated on the groove track  24  must be established appropriately to identify the recording mark formed on the land track  22  with the recording mark formed on the groove track  24 . 
     Further, the optical information recording apparatus according to an embodiment of the present invention includes a motor driver  90  for controlling a rotation speed of the optical recording medium  20  depending on a control signal from the controller  110 , and a spindle motor  100  for rotating the optical recording medium  20  upon a control of the motor driver  90 . The motor driver  90  adjusts differently the rotation speed of the spindle motor  100  in accordance with the land and groove tracks  22  and  24  such that the temperature profiles on the land and groove tracks  22  and  24  are equal to each other. Then, the controller  110  responds to the land/groove identification signal and generates the control signal for controlling the motor driver  90 . 
     A method for adjusting the rotation speed of the optical recording medium  20  will be described. The method for adjusting the rotation speed of the optical recording medium  20  allows the recording marks formed on the land and groove tracks  22  and  24  to be the same to each other in length. In detail, the controller  110  allows the motor driver  90  to rotate the optical recording medium  20  at the rotation speed higher than a previously established rotation speed when the land/groove distinguishing stage  60  identifies that the groove track  24  has been accessed, thereby forming the recording marks corresponding to the CHBS on the groove track  24  of the optical recording medium  20  rotated at the low rotation speed. Meanwhile, if the land/groove distinguishing stage  60  identifies that the land track  22  has been accessed, the controller  110  enables the motor driver  90  to rotate the optical recording medium  20  at the previously established rotation speed so as to form the recording marks corresponding to the CHBS on the land track  22  of the optical recording medium  20  rotated at the high rotation speed. In this to case, the rotation speed of the groove track  24  must be set up appropriately such that the recording marks formed on the land and groove tracks  22  and  24  are the same to each other in length. FIG. 7 shows temperature profiles on the land and groove tracks  22  and  24  responding to the rotation speed. In FIG. 7, a curse  11  represents a temperature profile on the groove track varying with the rotation speed of the optical recording medium  20 . Another curse  13  shows a temperature profile on the land track  24  responding to the rotation speed of the optical recording medium  20 . Referring to the curses  11  and  13  of FIG. 7, the temperature on the land and groove tracks becomes high and after low in a constant range of rotation speed. In other words, the recording marks formed on the land and groove tracks  22  and  24  can be equal to each other by mean of establishing the rotation speed of the groove track  24  lower than that of the land track  22 . In this case, the rotation speed of the groove track  24  must be set up to an appropriate rotation speed lower than that of the land track  22  to identify the recording mark formed on the land track  22  with the recording mark formed on the groove track  24 . Also, the recording marks formed on the land and groove tracks  22  and  24  can be equal to each other by mean of establishing the rotation speed of the groove track  24  higher than that of the land track  22 . In this case, the rotation speed of the groove track  24  must be established in the proper rotation speed higher than that of the land track  22  to identify the recording mark formed on the land track  22  with the recording mark formed on the groove track  24 . 
     As described above, an optical information recording apparatus and a method according to the present invention adjusts the power level of the light beam, the duty ratio of the light beam pulse, or the rotation speed of the optical recording medium in accordance with the land and groove tracks on the optical recording medium, thereby forming the recording marks having the same length on the land and groove tracks. Further, since the recording marks are formed on the land and groove tracks in the same length, an optical information recording apparatus and a method according to the present invention can record an information on the optical recording medium in the high density. 
     Although the present invention has been explained by the embodiments shown in the drawings described above, it should be understood to the ordinary skilled person in the art that the invention is not limited to the embodiments, but rather that various changes or modifications thereof are possible without departing from the spirit of the invention. Accordingly, the scope of the invention shall be determined only by the appended claims and their equivalents.