MXPA97003324A - Registration media, optic information reproduction apparatus and localization method - Google Patents

Abstract

Reduce problems related to the right of industrial property, reduce a need to collect a disco optic for, for example, use to rent and also allow the optical disc itself to be inhibited from use for rent. A reproduction film whose reflectance is changed by irradiating a laser beam having a higher intensity than a predetermined one is formed, the depth of the pre-bite in a data section is graduated to less than a quarter of the wavelength of a laser beam and the reproduction film is composed in such a way that its reflectance decreases if it is irradiated by a laser beam having a higher intensity than that of a predetermined level

Description

"REGISTRATION MEDIA, OPTICAL INFORMATION REPRODUCTION APPARATUS AND LOCALIZATION METHOD" BACKGROUND OF THE INVENTION 1. FIELD OF THE INVENTION This invention relates to a recording medium capable of optically reproducing recorded information, an optical information reproducing apparatus for reproducing the recorded information stored in the recording medium and a location method using the optical information reproducing apparatus. 2. DESCRIPTION OF THE PREVIOUS TECHNIQUE Conventionally, there have been optical discs which are recording means capable of reproducing the registration data. For example, as an optical rewriting disc, there are the magnetic optical disks (MO disk, including the so-called MD (minidisk, mark)) and the optical disk of phase change type and the like. Since a disc capable of recording only once write-only and multi-reading (WOR) is available and as a disc designed for read only, so-called CD-ROMs and the like are sold today.

With respect to the aforementioned optical rewriting discs, a number of rewrites for example is approximately 10 ^ times, and a number of reproductions, for example about 109 times. In optical discs where registration can be carried out only once, a registration number is only one and a reproduction number is, for example, approximately 10 ^ times. On optical discs designed for read-only, a registration number is one and a reproduction number is theoretically unlimited. All the different optical discs mentioned above contain a problem related to the intellectual property right. That is, even if for example the registered data is processed with mixed or similar for only users who have an appropriate privilege of use in industrial property rights viewpoints to solve the mixing and reproduce the registered data, if anyone obtains a The means to solve this mixture can capture the freely registered data even if it is not a person who has an appropriate privilege in terms of industrial property rights. In addition, anyone can capture the recorded data for unlimited times of optical discs to be used for distribution purposes, for example, optical discs that are allowed, for example, to be rented. Therefore, it is necessary to pick up these optical discs if an appropriate term is passed. That is, even if a user who has a license to rent an optical disc can be said to be a privileged person appropriate for the use of that optical disc within a rental period, if the rental period has already passed, he loses his privilege to appropriate use. In this way that optical disk must be collected. In addition there is a case in which it is not desired that an appropriate optic disk be rented due to intellectual property rights reasons.

COMPENDIUM OF THE INVENTION The present invention has been proposed to solve these problems. Therefore, an object of the present invention is to provide a recording medium that is capable of reducing the problems related to the intellectual property right and if the recording medium is an optical disc that is allowed to be used for rent, reduce a need to collect that optical disk, and also allow the optical disk itself to be inhibited from use for rent. In accordance with an aspect of the present invention, a recording means is provided having pitting where the information is reproduced by irradiating a beam on the pitting, the recording means also contains reproduction films to generate the pitting where the reflectance of they are changed by irradiating a laser beam having a higher intensity than a predetermined value. In accordance with another aspect of the present invention, a recording means according to claim 1 is provided., wherein the reflectance of the reproduction film decreases when a laser beam having a higher intensity than the predetermined value is irradiated. In accordance with still another aspect of the present invention, a registration means according to claim 2 is provided, further comprising address sections for recording the address information and data information sections for recording the data information by means of of the bites. In accordance with a further aspect of the present invention, a recording means according to claim 3 is provided, wherein the data information sections of generated by pitting and depth of pitting is between? / 8 + n ? / 2 and? / 6 + n? / 2 (n is an integer except 0) assuming that a wavelength of the laser beam is 1. In accordance with a still further aspect of the present invention, a recording means is provided according to claim 3, wherein the sections of address information are generated by pitting and the pit depth is essentially between? / 4 +? / 2 (n is an integer except 0) assuming that the wavelength of the laser beam is 1. In accordance with a still further aspect of the present invention, there is provided a recording means according to claim 4, further comprising a groove in at least one side of both sides of the laser beam. and the bite in the scanning direction of the laser beam, the direction information sections being formed by forming the slots in an oscillating configuration. In accordance with still a further aspect of the present invention, there is provided a recording means according to claim 4, further comprising slots on both sides of the pit in the scanning direction of the laser beam, the slots being essentially one depth of? / 8 assuming that the wavelength of the laser beam is 1.

In accordance with still a further aspect of the present invention, a registration means is provided according to claim 4, wherein the address information sections are formed by oscillating the pittings. In accordance with still a further aspect of the present invention, a recording medium is provided according to claim 1, wherein the reproduction film includes a first layer made of Sb2Se3, a second layer made of Bi2Te3 and a third layer manufactured of Sb2Se3 and when irradiated to the laser beam in the reproduction film, the first layer, the second layer and the third layer are melted, mixed and alloyed to change the reflectance. In accordance with a still further aspect of the present invention, a recording means according to claim 3 is provided, wherein the address information sections and the data information sections are formed by pitting and a spatial frequency in wherein the sting in the address information section is read by laser beam that is graded to be less than a spatial frequency at which the sting in the data information section is read by the laser beam.

In accordance with a still further aspect of the present invention, a recording means according to claim 1 is provided, further comprising another reproduction film whose reflectance is changed if a laser beam having a higher intensity than the predetermined value, the other reproduction film being formed on an opposite side to the side having the reproduction film. In accordance with a still further aspect of the present invention, there is provided an apparatus for reproducing the recording medium for reading the information optically from a recording medium, comprising an optical head for irradiating the optical beam on the recording medium; a light detecting means for receiving light reflected from the recording medium and emitting a detection signal; a demodulation means for demodulating the detection signal and issuing a demodulated signal; an error correction means for detecting errors in the signal of the demodulated data, correcting the error and outputting reproduced data signals; and a means of controlling the power of the reproduction beam to control the power of the beam, of the reproduction light beam to be irradiated from the optical head. According to a still further aspect of the present invention, there is provided an apparatus for reproducing the recording medium according to claim 12, further comprising a locating means for locating the optical head in a desired position, controlling the control of the power of the reproduction beam in order to irradiate the light beam from the optical head in a first laser power to the regular reproduction time and controlling during the localization operation, in order to irradiate the light beam from the optical head to a second laser power that is smaller than the first laser power. In accordance with still a further aspect of the present invention, there is provided a method for locating the optical head at a desired position in the recording medium, comprising: a process of irradiating the light beam to irradiate the light beam from the optical head to the registration means; a light detection process for receiving light reflected from a recording medium and emitting detection signals; a demodulation process to demodulate the detection signals and output the signals of the demodulation data; an error correction process to detect errors in the demodulation data signals; correct errors and issue reproduced data signals; a localization process for locating the optical head in a desired position in the recording medium; a first control process to control in order to irradiate the light beam from the optical head to a first laser power at the time of ordinary reproduction; and a control process for controlling, during the location operation in order to irradiate the light beam from the optical head to a second laser power that is smaller than the first laser power.BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 shows a perspective view of an optical disk according to the present invention. Figure 2 is an enlarged partially broken away perspective view of the optical disc shown in Figure 1. Figure 3 is a diagram for explaining a relationship between a slot and a pit of an optical disc according to the present invention. Figure 4 is a sectional view showing a configuration of a reproduction film of the optical disc according to the present invention. Figure 5 is a diagram for explaining a relationship between the depth of a pit or groove in the optical disc and the degrees of modulation before and after irradiation of the laser beam in accordance with the present invention. Figure 6 is a diagram for explaining the spatial frequency of a sting in the direction section and the spatial frequency of a sting in the data section. Figure 7 is a diagram showing a relationship between the spatial frequency of the address section and the spatial frequency of the data section and the amplitude. Figure 8 is a waveform diagram for explaining the signal waveforms reproduced in the address section and the data section before and after irradiation of the laser beam and the levels thereof. Figure 9 is a diagram for explaining an optical disc that allows reproduction on both sides. Figure 10 is a partially broken perspective view of an optical disk in which the slots are formed in an oscillating configuration. Figure 11 is a partially broken perspective view of an optical disk wherein the pits are formed in an oscillating configuration.

Figure 12 is an optical disc apparatus for reproducing an optical disc in accordance with the present invention. Figure 13 is a flow chart for explaining a location operation in the optical disc apparatus in accordance with the present invention.

DETAILED DESCRIPTION OF THE PREFERRED MODALITIES Next, preferred embodiments of the present invention will be described, with reference to the accompanying drawings. Figure 1 shows an optical disk which is an example of a recording medium in accordance with the present invention. Referring to the same Figure, the reference number 1 designates an optical disk belonging to a compact disk (CD), such as CD-ROM and the like, which includes a central hole 2a which is made to open to both sides of the disk , a registration area a in which, for example, the code information is recorded and a non-registration area (holding area) that extends around the opening portion of the central area 2a.

Figure 2 is an enlarged partially broken away perspective view of the optical disk 1 shown in Figure 1. With reference to Figure 2, the optical disk 1 according to the present invention includes a substrate 29 made of transparent material, such as for example, polycarbonate or the like, the reproduction film 30 in which the signals are recorded by means of a pre-bite and the recorded signals are reproduced by irradiating therein the laser beam, the protective film 21 to protect the film 30 from reproduction as its prominent factors and these elements are stacked in layers configuration. The optical disc according to the present invention has tracks 12 and grooves (guide groove) 13 in the reproduction film 30 and in addition the tracks 12 have punctures 14 formed as pre-pitting. That is, this bite 14 is formed by sealing according to a master disc wherein the signals are preliminarily recorded by pitting when the optical disc is produced. Therefore, by irradiating the laser beam on the track 12 in which the stings are formed, its reflected radius is read so that the signals recorded on that optical disk can be reproduced. In the meantime, this type of signal reproduction method for optical discs is already known in an optical disk aatus for CD-ROM. Figure 3 shows a sectional view of the optical disc shown in Figure 1 in a direction of the radius. Assuming that the wavelength of the aforementioned laser beam is?, In the optical disk 1 according to the present invention, a depth DG of the aforementioned slot 13 is graduated up to? / 8. On the other hand, in the optical disc 1 according to the present invention, approximately a depth DP of the aforementioned pit 14 formed in the track 12, a depth of a pit for the record data is of? / 8 -? / 6 and a depth of a sting for the direction (e.g., the direction of the track, etc.) is graduated to? / 4. The depth DG of lane 13 mentioned above can be any depth if the condition of? N / 2 +? / 8 (n is an integer except 0) is satisfied. The depth DP of the aforementioned sting 14 can be of any depth if the depth of the sting to record the data satisfies? n / 2 +? / 8? -? n / 2 +? / 6 (n is an integer except 0) and the depth of the sting for the address satisfies? n / 2 +? / 4 (n is an integer except 0). However, it is desirable to apply DG =? / 8, DP =? / 8 -? / 6 previous (to record the data) and DP =? / 4 (for the address) where the amplitude of the waveform of the Signal is converted to the maximum when using the so-called friction / traction method. As shown in Figure 4, the reproduction film 30 of the optical disc 1 according to the present invention has four layers comprising a reflective film 22 made of Al to reflect the irradiated laser beam, a first reproduction film 23 made of Sb2SE3, a second reproduction layer 24 made of Bi2Te3 and a third reproduction layer Sb2Se3, these layers being formed on the substrate 29. Even when the aforementioned first and third reproduction layers 23-25 form separate layers of amorphous condition (no crystalline) before irradiation of the aforementioned laser beam, if the laser beam having a more intense power than a predetermined power is irradiated, these first to third reproduction layers 23-25 are melted and mixed so as to form a alloy if the laser beam stops and they are left as they cool naturally. That is, as shown in Figure 4, an area 26 that cools naturally after the aforementioned area of the laser beam is irradiated is not in a condition in which the different layers of the former are formed separately. the third layer 23-25 of reproduction in an amorphous condition, but in this condition where the materials composing the first to third layers 23-25 of reproduction are mixed and remain alloyed. On the other hand, if the power of the irradiated laser beam is less than the predetermined value above, the melting and mixing of the first to third reproduction layers 23-25 never occurs or very little happens. The aforementioned reproduction film 30 produces a different reflectance between then the first and third reproduction layers 23-25 which are in an amorphous condition and when they are alloyed. For example, if the reflectance of the reproduction film 30 before irradiation of the laser beam having a more intense power than the previously predetermined value is assumed to be Rb, and the reflectance of the reproduction film that has been alloyed by irradiating the laser beam having a more intense power than the previously predetermined value is assumed as being Ra, a ratio of Rb >can be established; Ra. On the other hand, if the power of the irradiated laser beam is less than the above-mentioned predetermined value, the fusion and mixing of the first and third reproduction layers 23-25 never occurs or very little happens. Therefore, the reflectivity Rb and Ra are the same or slightly different from one another. Meanwhile, the aforementioned reflectance Rb and Ra can be arbitrarily changed by changing a ratio in the thickness of the film between the first and third reproduction layers 23-25. For example, this relationship can be changed to Rb < Ra. Due to the reasons described above, in the case in which the reflectance of the aforementioned reproduction film 30 is changed from Rb to Ra (Rb> Ra) by irradiation of the laser beam having a more intense power of a predetermined value, assuming that a degree of modulation of the aforementioned address section prior to irradiation of the laser beam is LAb and a degree of modulation of the address section after irradiation of the laser beam is LAa, a ratio of the degree of modulation LAb and LAa, just before and after irradiation of the laser beam is LAb > The A. The aforementioned modulation degree LAb corresponds to a level of a reproduced signal waveform that is obtained in the steering section when the laser beam is initially irradiated on the steering section. The aforementioned modulation degree LAa corresponds to a level of a reproduced signal waveform which is obtained just when the laser beam is irradiated in the direction section and then the laser beam is again irradiated in that direction section.

In a case in which the reflectance of the aforementioned reproduction film 30 is changed from Rb to Ra (Rb> Ra) by irradiation of a laser beam having a more intense power than a predetermined value, assuming that the degree The modulation of the aforementioned data section before the irradiation of the laser beam is LDb and a degree of modulation of the direction section after irradiation of the laser beam is LDa, a ratio of the modulation degrees LDb and Lüa just before and after irradiation of the laser beam is LDb > LDa. The aforementioned degree of modulation LDb corresponds to a level of a reproduced signal waveform that is obtained in the data section when initially irradiated to the laser beam on the data section. The aforementioned degree of modulation LDa corresponds to a level that a reproduced signal waveform obtained just when the laser beam is irradiated in the data section and when the laser beam is irradiated again in that data section. Figure 5 shows a relationship between pit depth or slot and degree of modulation (and waveform level of reproduced signal) before (before exposure) and after (after exposure) beam irradiation To be. Referring to Figure 5, a continuous line in the same Figure indicates a relationship between the depth of the pit or slot and the degree of modulation before exposure. The dotted line in the same Figure indicates a relationship between the depth of the pit or slot and the degree of modulation after exposure. As is evident from Figure 5, the degree of modulation in the largest when the depth of the slot or pit is? / 4 (the level of the signal waveform reproduced that becomes the largest). As the depth of the pit or slit is closer to 0 or? / 2, the degree of modulation decreases (the level of the signal waveform reproduced decreases). As described above, the sting 14 in the direction section is? / 4 in depth and the sting 14 in the data section is? / 8 -? / 6 in depth. Therefore, as will become apparent from Figure 5, in the direction section where the depth of the sting is? / 4, the degrees of modulation (level of the signal waveform reproduced) before and after the irradiation of the laser beam are LAb and LAa as shown in the same Figure, and the degree of modulation of LAa after exposure is quite large. On the other hand, as is evident from Figure 5, in the data section where the depth of the sting is? / 8 -? / 6 (only? / 8 is indicated in Figure 5), the degrees of modulation ( level of the waveform of the reproduced signal) before and after laser irradiation (before and after exposure) are LDb and LDa and the degree of LDb modulation before exposure is quite large. However, the LDa degree of modulation after exposure is very low. We now take into account the case in which an optical disc having the reproduction film 30 whose reflectance is changed before and after irradiation of the laser beam as described above, will be reproduced with an optical disc reproducing apparatus. that has existed since before. Here, suppose that the error correction capability (correction capability of the error correction code (in the ordinary optical disc playback apparatus is 10 ~ 3, when converted to a reproducing signal error rate and suppose that an error rate of a reproduction signal in which a bite of the data section having the degree of modulation LDb before irradiation of the laser radio is reproduced is 10 ~ 4 and suppose further that an error rate of one reproduction signal wherein the bite of the data section having the LDa degree of modulation after irradiation of the laser beam is for example 10 ~ 2, the ordinary optical disc reproducing apparatus having only a correction error capability of up to 10 ~ 3 under the aforementioned error rate can not correct errors in reproduced signals from a sting in the data section after irradiation of the laser beam even though it can correct errors in the reproduced signals of a bite in the data section before the exposure of the laser beam. On the other hand, as shown in Figure 5, because the degree of modulation before and after irradiation of the laser beam in the steering section is greater than the degree of modulation before and after irradiation of the laser beam in the data section, the aforementioned ordinary optical disc reproducing apparatus can correct errors in reproduced signals of a sting in the steering section at any time before and after the laser beam irradiation. This means that if the optical disc according to the present invention is reproduced with an ordinary optical disc reproducing apparatus, the data section can be reproduced only once, but can not be reproduced a second time and subsequently, because it is disabled. the error correction. On the other hand, it is intended that the address section may be reproduced a second time and subsequently. In other words, if the depth DP of the sting in the data section is graded in order to obtain a degree of modulation where the error rate of a reproduction signal after irradiation of the laser beam exceeds the correction capability of In addition to the reflectance Rb and Ra of the reproduction film 30 are thus graduated, this section of data can be designed so as to be reproducible only once, but not reproducible by second time and later. In this way, if the optical disc is related to a specific industrial property right, it eliminates a possibility of collecting the data stored in that optical disk for unlimited periods of time. If that optical disk is designed for distribution to limited destinations, it eliminates a need to collect those optical discs. In addition, because the optical disk according to the present invention can allow the reproduction of its data only once as described above, it is not appropriate for rent or rental use, assuming multiple uses. Therefore, this optical disk is effective in a case in which that disk is not desired to be used for rent due to the reason of the intellectual property right. Then, the optical disk according to the present invention has the aforementioned reproduction film 30 and as shown in Figures 6 and 7, the respective stings 14D for recording the data are assigned to the track 12 in such a way that its spatial frequency It is high (MTF). On the other hand, the respective stings 14A for the address are assigned in such a way that their spatial frequency is low. That is, in the optical disk according to the present invention, the signal components of the registration data are concentrated on the side of the high frequency band in order to increase the recording density of the data section in the track 12. On the other hand, the components of the direction signal are concentrated on the low frequency band side in order to decrease the recording density of the address section. Figure 6 shows the pin assignment at a boundary between the data section and the address section and further indicates a laser zone 15. In addition, Figure 7 shows a relationship of the spatial frequency in the address section and the data section. Because in the optical disk according to the present invention is or is described above, the depth of the sting in the direction section is? / 4 and the depth of the sting in the data section is? / 8 -? / 6, the amplitude of the reproduced signal waveform is large in the address section and small in the data section as shown in Figure 7. As described above, the spatial frequencies for the data section and The direction section is divided and as described above, the depth of the sting in the direction section is? / 4 and the depth of the sting in the data section is? / 8 -? / 6. As a result, as shown in Figures 8A and 8B, the reproduced signals of the address section and the data section can be easily distinguished. If the spatial frequency of the address section is reduced, even though the level of the signal waveform reproduced is decreased as described above, the information of that address section can be read with complete certainty. Figure 8A shows a reproduced signal waveform and the level before irradiation of the laser beam (ie, the signal waveform reproduced and the level obtained from the irradiation of the laser beam for the first time) and Figure 8B shows the waveform of the reproduced signal and the level after irradiation of the laser beam (ie, the waveform of the reproduced signal and the level obtained by irradiation of the laser beam a second time and subsequently). In addition, the optical disc 1 according to the present invention can be modified to make an optical disc 50 that allows reproduction on both sides. In this case, two pieces of the same optical disk having the structure shown in Figure 1 are prepared and linked together with the protective films 21 facing each other. That is, two layers indicated by the reference number 40 in Figure 9, include the protective film 21 and the reproduction film 30, as shown in Figure 2. The respective reproduction films 30 are structured to be irradiated by lightning laser from both sides of the optical disc 50 through the substrates 29. Furthermore, by bonding the protective films 21 of the two layers 40 through an adhesive layer 20, the optical disc allowing the reproduction in both sides. As described above, in accordance with the optical disk of the present invention, software that can be played only once, for example (audio, image, game software, etc.) can be supplied in a form of a optical disk designed for read only that can be produced by punching out a master disk. Therefore, it is possible to achieve protection of the right to additional intellectual protection in an effective manner. In the aforementioned example, it is manifested that the address information is recorded on the track 12 by means of a pre-bite. Different from a case in which the address information is recorded in the track 12 by means of the pre-bite as shown, for example, in Figure 10, it is possible to achieve the registration of the address information by forming the slots 13. by oscillating and modulating the frequency of the oscillation corresponding to the address information. Furthermore, as shown in Figure 11, it is possible to record the address information by oscillating an assignment of the pre-pits in a movable direction of the track, whereas the pre-pits are designed for only the data. In this case also, by modulating the oscillatory frequency of the pre-pits so that it corresponds to the address information, the address can be recorded. In this way, it is not necessary to form pitting for the direction in the track 12. Then, when it is desired to reproduce only the data in a specific track of the optical disc, the location is carried out. However, the area of the laser beam during the location operation moves above the data section as well as in the direction section.

During this time, if a power of the laser beam is greater than the previously predetermined value and the area of the laser beam sits in the data section in the period of time in which the first to third reproduction layers 23, 25 are melted, there is a risk that the data section can be transformed to not be reproducible only by localization through that portion. An optical disc reproducing apparatus for preventing this phenomenon will be described with reference to FIGS. 12 and 13. This optical disc apparatus operates in order to decrease the location operation during the lowest laser beam to approximately half the time during the ordinary reproduction. Figure 12 shows a schematic construction of a disc reproduction apparatus 100 for reproducing the signals from an optical disc 1 which is being rotated. Referring to Figure 12, an optical disc 1 which is a disc-shaped recording medium is driven to rotate by a spindle motor 103 through an arrow 102. This spindle motor 103 contains a signal generator FG for emitting FG signals accompanied by a rotation of the spindle motor 103 detecting the magnetic flux in a magnet. The spindle motor 103 is driven to rotate by the spindle drive signals, generated by a spindle control system 111 based on the signal FG from the aforementioned signal generator FG 104 and is subjected to a servo-spindle. The spindle control system 111 allows the rotation speed of the spindle motor 103 to be changed by control from a system controller 107. If an optical disk 101 is driven to rotate according to the area of Example CAV (angular velocity constant) or the CLV zone (linear velocity constant), the rotation speed of the optical disk 101 must be changed for each zone. In this way, the controller 107 of the aforementioned system controls the spindle control system 111 to change the rotation speed of the optical disk 101. During this time, the system controller 107 determines whether the rotation speed of the optical disk 101 reaches a predetermined speed based on the latching / unlocking signal FG from the latch detector 112 FG. The aforementioned latching detector FG 112 determines whether the rotation of the spindle motor 103 is engaged by detecting the fluctuations in the signal FG of the signal generator 104 FG and, in accordance with a result of this detection, emits the latching / uncoupling signals FG. previously cited. The aforementioned latching detector FG 112 contains the circuit PLL (phase-locked circuit) for the phase locking of the signal FG mentioned above by means of the circuit PLL. An optical head 105 includes an optical part that includes a laser beam source such as a laser diode and a target lens. An optical system composed of a photodetector having a beam receiving portion for the predetermined pattern and the like, and a biaxial actuator for driving the objective lens vertically in the focus direction and horizontally or in the tracking direction. Furthermore, the optical head 105 is structured so as to be movable in the direction of the diameter of the disk by means of a mechanism comprising a sliding or sled motor comprising a slide motor and a slide rail. In the optical head 105, the laser beam projected from the laser diode of the aforementioned optical system is concentrated in the disk 101 through the objective lens. During this time, the optical head 105 moves the objective lens in the focusing direction by means of the biaxial actuator to focus on the aforementioned disc registration surface and also moves the objective lens in the tracking direction to apply the focus point to the lane on the record surface of the aforementioned disk. On the other hand, the ray reflected from the optical disk 101 is introduced into the aforementioned photodetector through the objective lens of the optical system. In this photodetector, the introduced beam is converted into electrical signals by a photoelectric conversion process. The output signals of the optical head 105 are transmitted to a servo signal generation circuit 109. this servo signal generation circuit 109 detects, for example, the focusing error signals based on the so-called calculation method or the tracking error signals based on the friction / traction method from the output signals of the optical head 105 . The aforementioned focus error signals and tracking error signals from the servo signal generating circuit 109 are transmitted to the servo control system 110. The servo control system 110 drives the biaxial actuator of the optical head 105 based on the focus error signal and the tracking error signal mentioned above to carry out the servo-focusing and servo tracking. In addition, the servo control system 110 generates driving signals of the slide to move the optical head 105 to a destination position in the direction of the diameter of the disk based on the control of the system controller 109 and transmits this driving signal of the slide to a slide driver that is provided in the head 105 optics. Receiving the slide driving signal, the slide driver drives the slider motor of the above-mentioned sliding mechanism. As a result, the optical head 105 moves toward the radio direction of the optical disk 1. When the signals recorded on the optical disc 101 are reproduced in a state in such a manner that the servo, servo, and servo tracking are being performed, the disc reproduction apparatus 100 shown in FIG. 12 operates as follows: signals read by the optical head 1 of the optical disc 1 are transmitted to the playback system 108. This reproduction system 108 demodulates the reproduced signals of the optical disc 101 and carries out the error detection and correction thereof, the signals reproduced by this reproduction system 108 are for example transmitted to the host computer which is an external component to through a system controller 9 and in addition a terminal 113.

Here, the location operation for the optical head 105 to a destination position on the optical disk 1 will be described with reference to Figure 13. The system controller 109 determines whether an address has been received from the host computer (SI). the destination location position and a location command. If the location command has not been received, the processing returns to SI in such a way that it awaits the location command. If the location command is received, the system controller 109 outputs a signal that divides half the laser power to halve the laser power to a laser power control circuit 106. Correspondingly, the circuit 106 that halves the power of the laser controls the laser beam source to halve the power of the laser beam at the time of reproduction (S2). Then, the slider motor is driven to move the optical head to a destination position on the optical disk to begin the location operation (S3). During this time, the laser power is adjusted by half at the time of reproduction so that even when the data section is irradiated by the laser beam during the location operation, the reproduction layer 30 of the data section, it does not melt, mix or remain alloyed. Therefore, there is little possibility that reflectance can be changed. Namely, the data in the data section is not deleted so that it can be read to a regular reproduction. Because the depth of the sting for the direction in the direction section is? / 4, even when half the laser power is divided, the direction of the current position of the optical head can be read through the system 108 Of reproduction. Then, whether or not the current position address of the optical head supplied from the optical head 105 to the system controller 109 through the playback system 108 matches, is determined with a destination address transmitted from the host computer together with the remote control. of location (S4). If they do not coincide with each other, a process to determine if the current position address matches the destination address is repeated (S4). If it is determined that the position address matches the destination address, the system controller 109 outputs a laser power reset signal to the laser power control circuit 106. Correspondingly, the laser power control circuit 106 controls the source of the laser beam to return the power of the laser to a laser power at the time of reproduction (S5). By irradiating the laser beam in the laser power at the time of reproduction from the destination address position, the data is reproduced in the data section. During this time, the laser beam of the laser power during this time is melted, mixed and alloyed to the reproduction layer 30 of the data section. Consequently, the reflectance of the reproduction layer 30 decreases. That is, the data in the data section is deleted so that it can not be reproduced again. In this way, each time the localization command of the host computer is transmitted, the operation described above is repeated. Even when the laser beam power is halved, the information of the steering section can be read because the steering section has a large level in the form of a reproduced signal wave and an excellent S / N ratio as described above. On the other hand, as for the data section, because the data section originally has a small level in the waveform of the aforementioned reproduced signal and a poor S / N ratio, if the power of the laser beam it is reduced by half, at the time of ordinary reproduction, the information of that section of data can not be seen. Nevertheless, the signals recorded in the data section do not need to be read during the location operation and it is possible to prevent the signals in the data section from being incapable of being read by the location operation. Even when the power of the laser beam must be returned to its ordinary power level, after the localization operation is completed as manifested in the present invention, if there is no opportunity for the laser beam area to settle through the the data section for more than the time in which it fuses the first to third layers 23-25 of reproduction, the above-described operation of the laser power is not necessary. As is evident from the description carried out above according to the present invention, a reproduction film is formed whose reflectance is changed by irradiating the laser beam having a greater than a predetermined intensity, the depth of a pre-bite in the data section where the data is recorded by means of pre-pits, it is graduated to less than a quarter of the wavelength of a laser beam, if the reproduction film is composed in such a way that its reflectance decreases which is irradiated by a laser beam having an intensity greater than a predetermined level. As a result, the problem related to the right of industrial property can be reduced. For example, for even optical discs are allowed to renten, a need to collect that optical disk can be removed and at the same time it is possible to make that optical disk inhibited, is used to be able to rent. In addition, because the laser power for reproducing the optical beam is reduced during the location operation of the reproduction apparatus of the recording medium in accordance with the present invention, the data in the recording medium is never suppressed during the operation of location. In addition, because the steering section can still be read by a weak laser power, an attempt can be made to secure a destination position.

Claims (14)

CLAIMS:

1. A recording medium having stings where the information is reproduced by irradiating the beam on the stings, the recording medium also contains reproduction films to generate the stings in which the reflectance of them is changed by irradiating a laser beam having a intensity higher than a predetermined value.

2. A recording medium according to claim 1, wherein the reflectance of the reproduction film decreases when a laser beam having a higher intensity than a predetermined value is irradiated.

3. A recording medium according to claim 2, further comprising address sections for recording the address information and data information sections for recording the data information by means of the pits.

4. A recording medium according to claim 3, wherein the data information sections generated by the pits and the depth of the pits is between? / 8 + n? / 2 and? / 6 + n? / 2 (n is an integer except 0) assuming that a wavelength of the laser beam will be?

5. A recording medium according to claim 3, wherein the sections of address information are generated by pitting and the depth of the pitting is essentially between? / 4 +? / 2 (n is an integer except 0) assuming that A wavelength of laser beam will it be?

6. A recording medium according to claim 4, further comprising a groove in at least one side of both sides of the pit in the laser beam scanning direction, the address information sections are formed by forming the grooves in oscillating configuration.

7. A recording medium according to claim 4, further comprising slots on both sides of the pit in the scanning direction of the laser beam, the slots are essentially? / 8 in depth assuming that the beam wavelength laser be?

8. A recording medium according to claim 4, wherein the address information sections are formed by oscillating pits.

9. A recording medium according to claim 1, wherein the reproduction film comprises a first layer made of Sb2Se3, a second layer made of Bi2Te3 and a third layer made of Sb2Se3, and when the laser beam is irradiated on the The reproduction film, the first layer, the second layer and the third layer are melted, mixed and remain alloyed in order to change the reflectance.

10. A recording medium according to claim 3, wherein the address information sections and the data information sections are formed by pitting and a spatial frequency which the sting in the address information section is read. by the laser beam that is graded to be smaller than the spatial frequency at which the sting in the data information section is read by the laser beam.

11. A recording medium according to claim 1, further comprising another reproduction film whose reflectance is changed if the laser beam having a higher intensity than a predetermined value is irradiated, the other reproduction film is formed in a side of the side that has the playback movie.

12. An apparatus for reproducing a recording medium for reading the information optically from a recording medium, comprising: an optical head for irradiating the optical beam in the recording medium; a light detecting means for receiving the reflectance of the light from the recording medium and emitting a detection signal; a demodulation means for demodulating the detection signal and issuing a demodulated signal; an error correction means to detect errors in the demodulated data signal, correct the error and send reproduced data signals; and a reproduction beam power control means for controlling the power of the beam, of the reproduction light beam to be irradiated from the optical head.

13. A recording medium reproduction apparatus according to claim 12, further comprising a locating means for locating the optical head in a desired position, the power control means of the reproduction beam controls to irradiate the light beam from the optical head to a first laser power at the time of ordinary reproduction and to control during the localization operation in order to irradiate the light beam from the optical head to a second laser power that is smaller than the first power of To be.

14. A method for locating the optical head in a desired position in the recording medium, comprising: a process for irradiating the light beam, for irradiating the light beam from the optical head to the recording medium; a light detection process for receiving a light reflected from the recording medium and emitting detection signals; a demodulation process for demodulating the detection signals and issuing demodulation data signals; an error correction process to detect errors in the demodulation data signals, correct errors and send reproduced data signals; a localization process for locating the optical head in a desired position on the recording medium; a first control process to control in order to irradiate the light beam from the optical head to a first laser power at the time of ordinary reproduction; and a second control process to control during the location operation to irradiate the light beam from the optical head to the second laser power that is smaller than the first laser power.