MXPA01002576A - Methods and devices for recording marks in an information layer of an optical record carrier, and record carriers for use therein - Google Patents

Abstract

Methods and devices are described for writing an optical record carrier, in which a mark representing recorded data is written in a phase-change layer of a record carrier by a sequence of radiation pulses. A rear heating pulse (24) is introduced after a last write pulse (23, 26) and a front heating pulse (25) is introduced before the first write pulse (22,26). The power level (13) of the front heating pulse and the power level (15) of the rear heating pulse may be dependent on the length of the mark to be recorded and on properties of the record carrier. The method results in a reduced jitter of the marks written, especially when writing at high recording speeds.

Description

METHODS AND DEVICES FOR RECORDING BRANDS IN AN INFORMATION LAYER OF A CARRIER (CARRIER) OF OPTICAL RECORDING, AND RECORDING CARRIERS FOR USE IN THESE The invention relates to a method of recording marks representing data in a recording medium, said recording means comprising an information layer having a phase that is reversibly changeable between a crystal phase and an amorphous phase, when irradiating to the information layer with up pulse beam radiation, each mark is written by a sequence of pulses comprising at least one write pulse, the written marks can be erased by irradiating the information layer with a beam of radiation having a level of erasing power (e), a first pulse of writing a sequence of pulses that is preceded by a pulse of 'cooling having a cooling power level (c) which is less than the erasing power level (e), said radiation beam being generated by a radiation source. The invention also relates to a recording device for recording data in the form of marks in a recording medium, said recording medium comprises an information layer having a phase that is reversibly switchable between a crystal phase and a amorphous phase, by irradiating the information layer with a beam of pulsed radiation, the etched marks can be erased by irradiating the information layer with a beam of radiation having a level of erasing power (e), the device comprising a radiation source that provides the radiation beam and a control unit for controlling the power of the radiation beam, the control unit can be operated by providing a sequence of writing pulses to write a mark and control the beam power of radiation so that it has a cooling power level (c) that is lower than the level of erasing power (e) that precedes a first write pulse of a sequence of pulses. The invention further relates to a recording medium for use in a recording device, said recording medium comprises an information layer having a phase that is reversibly changeable between a crystal phase and an amorphous phase, and it comprises an area that contains recording parameters.

A method and recording device as described in the preamble are known from U.S. Patent 5,412,626. A mark is written by a sequence of writing pulses and previously written marks between the marks being written are erased by applying a level of erasing power (e) between the sequences. The known sequence has a cooling power level (c) immediately before a first write pulse of the sequence, the cooling power level (c) being less than the erasing power level (e). The level of cooling power (c) can be any power level less than the level of erasing power (e), including an out-of-level radiation source. The power level between the writing pulses can be any power level in the range between the erasing power level (e) and the cooling power level (c). As cooling power level (c) is found immediately before the first write pulse of the sequence, a stable recorded mark can be formed, resulting in a mark having a low movement. The movement is the standard deviation of the time differences between level transitions in a digitized reading signal and the corresponding transitions in a clock signal, the time difference is normalized by the duration of a period of said clock.

The known method is suitable for overwriting directly into a recording carrier, that is, when writing information that is to be recorded in the information layer of the recording carrier and at the same time the previously written information in the information layer is erased. A method for reducing motion in recording carrier phase change types is described in JPA 08287465. In this method, the edges of the write pulses in pulse sequences are changed in time. The degree of these time changes depends on the properties of the recording carrier and the recording device. In general, the time changes are very small compared to the duration of a writing pulse.

It is a drawback of the known method of US Pat. No. 5,412,626 that it does not carry sufficiently low the movement in the reading signal obtained from the written read marks when using the method, especially when the marks are written in high recording speeds. It is a drawback of the known motion reduction method of JPA 08287465 that this requires complex and expensive electronic application to produce the time changes with sufficient accuracy.

It is an object of the invention to provide a method for recording marks of the type described in the opening paragraph, having a reduced movement, without the need for complex and expensive electronic applications.

This objective is achieved when the method described in the preamble is characterized in that the last write pulse of a sequence is directly followed by a rear heating pulse having a level of rear heating power (r), the power level of rear heating (r) being greater than the level of erasing power (e). Instead of returning to a cooling power level (c) or an erasing power level (e) after a last write pulse in a pulse sequence, a rear heating pulse having a level of rear heating power (r) that is greater than the cooling power level (c), resulting in the movement of the marks that are smaller than the movement of the marks recorded by the known method. The modification of a power level in a sequence of writing pulses requires fewer complex and expensive electronic applications than are required to introduce very small changes in time to the edges of the writing pulses. In addition, electronic applications to provide different levels of power (such as the level of power to erase and the level of cooling power) are already available in the recording devices, and usually only one modification would be required to implement the method according to the invention. It may be apparent to a person skilled in the art that characterizations of the method according to the invention, introducing a rear heating pulse having more than one level of rear heating power, such as, for example, crossover power levels step from the level of writing power to the power level of erase, also results in reduced movement of the marks.

The method according to the invention in particular has advantages when used in combination with a recording carrier where a layer comprising an Al alloy is replaced by a layer comprising Si and a dielectric layer, as per For example, a layer comprising ZnS: SiO2. These types of recording carriers are known as Absorption Control recording carriers. A typical recording carrier of average a-pass data transmission comprises a layer of an Al alloy deposited on a substrate. Provided at the top of the composite layer of Al alloy are, successively, at least one dielectric layer, an information layer having a phase that is reversibly changeable between a crystal phase and an amorphous phase (i.e. , a phase change layer, and again at least one dielectric layer In Absorption Controlled recording carriers, the composite Al alloy layer is replaced by, successively, a composite layer of ANSI: SiO2 and a layer composed of Si on the art of the substrate A combination of the method according to the invention and a recording medium of the type of recording carriers Controlled Absorption described above results in a significant reduction of the movement of the marks, especially when the marks They are written in various recording speeds.

A characterization of the method according to the invention is characterized in that the rear heating power level (r) of the rear heating pulse depends on the properties of the recording medium. The level of rear heating power (r) can be assigned a fixed chosen value, alternatively, the level of rear heating power (r) can be assigned a value that depends on the properties of the individual recording camer in which the marks are recorded. The value of the rear heating power level (r) to be used by an individual recording carrier can be determined, for example, by a test procedure where the pulse sequences, with each sequence having a different value for the level of heating power (r), are used to record marks, and the resulting marks are read and analyzed. Other test procedures can be used alternatively. Finally, the optimum value for the rear heating power level (r) corresponding to an individual recording carrier can be recorded on that recording carrier. In this case, the value can be read directly from the recording carrier by a recording device.

A preferential characterization of the method according to the invention for recording marks having lengths of nT, where T represents the length of a period of a reference clock in a data signal and n represents a predetermined natural number greater than 1, is characterized in that the rear heating pulse has a first level of rear heating power (r1) when n = 2, a second level of rear heating power (r2) when n = 3, and a third power level of 'rear heating (r3) when n > 4, the first level of rear heating power (r1), the second level of rear heating power (r2) and the third level of rear heating power (r3) depend on the properties of the recording medium. A further reduction of the movement is obtained when, instead of using a single level of rear heating power (r) for all the marks to be recorded, the level of rear heating power becomes dependent on the length of the marks to be recorded. recorded. This results in a significant reduction of movement, especially of the shorter marks, that is, the marks that have a length of 2T and 3T. Each of the rear heating power levels (r1, r2 and r3) can be assigned values that depend on the properties of the individual recording carrier in which the marks are to be recorded. The values of the rear heating power levels (r1, r2 and r3) to be used by an individual recording carrier can be determined, for example, by a test procedure where the pulse sequences, with each sequence having different groups of values for each level of rear heating power (r1, r2 and r3) are used to record marks, and the resulting marks are read and analyzed. Other test procedures can be used alternatively. Finally, the optimum values for the rear heating power levels (r1, r2 and r3) corresponding to an individual recording carrier can be recorded on that recording carrier. In this case, the values can be read directly from the recording carrier using a recording device.

A characterization of the method according to the invention is characterized in that the first pulse of writing of a sequence is directly preceded by a frontal heating pulse having a level of rear heating power (r), the frontal heating pulse is directly preceded by the cooling pulse having a cooling power level (c), the frontal heating power level (f) being greater than the erasing power level (e). A further reduction of the movement is obtained when a frontal heating pulse is introduced between the cooling pulse and the first pulse of writing a pulse sequence, the frontal heating pulse having a frontal heating power level (f) which is greater than the erase power level (e). By introducing this frontal heating pulse, a symmetry is obtained between the frontal portion of a sequence of pulses and the rear portion of a sequence of pulses. The front heating power level (f) may have a value that is equal to the rear heating power level (r), or may have a value that is different from the rear heating power level (r).

A characterization of the method according to the invention is characterized in that the level of frontal heating power (f) of the frontal heating pulse depends on the properties of the recording medium. The front heating power level (f) can be assigned a fixed chosen value. Alternatively, the front heating power level (f) can be assigned a value that depends on the properties of the individual recording carrier in which the marks are to be recorded. The value of the front heating power level (f) to be used by an individual recording carrier can be determined by a test procedure or read directly from the recording carrier, as described above in the case of the characteristic characterization wherein the level of rear heating power of the rear heating pulse depends on the properties of the recording carrier.

A preferential characterization of the method according to the invention for recording marks having lengths of nT, where T represents the length of a period of a reference clock in a data signal and n represents a predetermined natural number greater than 1, is characterized in that the frontal heating pulse has a first level of frontal heating power (f1) when n = 2, a second level of frontal heating power (f2) when n = 3, and a third level of frontal heating power (f3) ) when n > 4, the first level of frontal heating power (f1), the second level of frontal heating power (f2) and the third level of frontal heating power (f3) depend on the properties of the recording medium. Instead of using a single level of front heating power (f) for all the marks to be recorded, the level of frontal heating power depends on the length of the marks to be recorded. This results in a significant reduction in Mftií = I ^ movement, especially of the shorter marks, that is, the marks that have a length of 2T and 3T. At each of the front heating power levels (f1, f2 and f3) a fixed chosen value can be assigned to them. Alternatively, the frontal heating power levels (f1, f2 and f3) can be assigned values that depend on the properties of the individual recording carrier in which the marks are to be recorded. The values of the frontal heating power levels (f1, f2 and f3) to be used by an individual recording carrier can be determined by a test procedure or read directly from the recording carrier, as described above in the case of characterization characterized in that the rear heating pulse has a first level of rear heating power (r1) when n = 2, a second level of rear heating power (r2) when n = 3, and a third Rear heating power level (r3) when n > Four.

A characterization of the method according to the invention is characterized in that the level of cooling power (c) of the cooling pulse depends on the properties of the radiation source and the recording medium. At the cooling power level (c) a fixed chosen value can be assigned to it. Alternatively, the level of cooling power (c) can be assigned a value that depends on the properties of the individual recording carrier in which the marks are to be recorded and the properties of the radiation source. The value of the cooling power level (c) to be used for an individual recording carrier can be determined by a test procedure as described above in the case of characterization characterized in that the power level of Rear heating depends on the properties of the recording carrier.

By assigning an optimal value to the level of cooling power (c), which depends on the properties of the individual recording carrier in which the marks are to be recorded and properties of the radiation source, a rapid transition of the level is obtained from cooling power (c) to either the frontal heating pulse power level (f) or 5 the power level of the first write pulse in a sequence. This results in well-defined markings that have a reduced movement.

A characterization of the method according to the invention for recording marks having lengths of nT, where T represents the length of a period of a reference clock in a data signal and n represents a predetermined natural number greater than 1, is characterized in that the cooling pulse has a first level of cooling power (d) when n = 2, a second level of cooling power (c2) when n = 3, and a third level of cooling power (c3) when n > 4, the first level of cooling power (d), the second level of cooling power (c2) and the third level of cooling power (c3) depend on the properties of the radiation source and the recording medium. Instead of using a single level of cooling power (c) for all the marks to be recorded, the level of cooling power becomes dependent on the length of the marks to be recorded. This results in a significant reduction of the movement, especially of the shorter marks, that is, the marks that have a length of 2T and 3T. Each of the cooling power levels (d, c2 and c3) can be assigned a fixed chosen value. Alternatively, the cooling power levels (d, c2 and c3) can be assigned values that depend on properties of the individual recording carrier in which marks and properties of the recording source are to be recorded.

«M = aaa» .j > Aafa. ,,% ». .? faith & jUamuu? Ar'ir > *? > .. »- .. - ~ < .- > . ^ < ^ JBI8i &El8IS8¡Ífa »i ^ &L-A ^« ftfe. »C» .xa? »C > a- a * a < ? «.- '< 6 ^,. »^ < ».» & .-. < t¿ »«? »j¡» ». * Jtt¿. radiation. The values of the cooling power levels (d, c2 and c3) to be used by an individual recording carrier can be determined by a test procedure as described in the previous case of characterization characterized in that the pulse rear heating has a first level of rear heating power (r1) when n = 2, a second first level of rear heating power (r2) when n = 3, and a third level of rear heating power (r3) when n > Four.

A characterization of the method according to the invention is characterized in that the rear heating pulse includes a front portion having a heating power level (r), and a rear portion having a power level that is lower than the level of erasing power (e).

Another object of the invention is to provide a recording device of the type described in the preamble, adapted for use in the method according to the invention.

This objective is achieved when the recording device described in the preamble is characterized in that the control unit is operative to control the power of the radiation beam in such a way that it has a rear heating pulse having a level of rear heating power. (r) that directly follows a last write pulse of a sequence, the rear heating power level (r) being greater than the erasing power level (e).

A characterization of the recording device according to the invention for recording marks having lengths of nT, where T represents the length of a period - ^ & ^ &ffli- ^ of a reference clock in a data signal and n represents a predetermined natural number greater than 1, characterized in that the recording device comprises means for determining a first value for the power level rear heating (r1) when n = 2, a second value for the rear heating power level (r2) when n = 3, and a third value for the rear heating power level (r3) when n > 4, said first value for the rear heating power level (r1), the second value for the rear heating power level (r2) and the third value for the rear heating power level (r3) depend on the properties of the recording medium.

A characterization of the recording device according to the invention is characterized in that the control unit is operative to control the power of the radiation beam in such a way that it has a frontal heating pulse having a frontal heating power level ( f) directly preceding a first write pulse and a cooling pulse having a cooling power level (c) directly preceding the frontal heating pulse, the one level of frontal heating power (f) being greater than the level of erasing power (e) and the cooling power level (c) being less than the erasing power level (e).

A characterization of the recording device according to the invention for recording marks having lengths of nT, where T represents the length of a period of a reference clock in a data signal and n represents a predetermined natural number greater than 1, is characterized wherein the recording device comprises means for determining a first value for the front heating power level (f1) when n = 2, a second value for the front heating power level (f2) when n = 3, and a third value for the frontal heating power level (f3) when n > 4, said first value for the front heating power level (f1), the second value for the front heating power level (f2) and the third value for the front heating power level (f3) depend on the properties of the recording medium.

It is another object of the invention to provide a recording medium of the type described in the preamble, adapted for use in the method and recording device according to the invention.

This objective is achieved when the recording medium described in the preamble is characterized in that the area containing recording parameters comprises a value for the heating power level (r). This objective is also achieved when the recording medium described in the preamble is characterized in that the area containing recording parameters comprises a value for the front heating power level (f). This objective is also achieved when the recording medium described in the preamble is characterized in that the area containing recording parameters comprises a value for the cooling power level (c). When using the method and recording device according to the invention, the heating power level (r), the rear heating power level (f) and the cooling power level (c), respectively, are you can assign a value that depends on the properties of the individual recording carrier in which the marks are to be recorded. The value for the rear heating power level (r), the front heating power level (f) and the cooling power level (c), respectively, corresponding to the individual recording carrier is recorded on a recording carrier according to the invention in an area that contains recording parameters. This value can be read directly from the recording carrier according to the invention by, for example, a characterization of the method and a characterization of the recording device according to the invention.

These and other objects, features and advantages of the invention will be apparent from the following more particular description of the characterizations of the invention, as illustrated in the accompanying drawings, wherein Figures 1 to 4 show diagrams comprising a dependency of time of the data signal and a corresponding control signal that controls the power levels of the radiation beam, Figure 5 shows a diagram of a first recording device according to the invention, and Figure 6 shows a diagram of a second recording device according to the invention.

Figure 1 shows diagrams composed of two signals, a digital data signal 10 and a control signal 20, as used in the method according to the invention. A Figure 1a provides the value of the digital data signal 10 as a function of time, the value of the signal representing the information to be recorded. The vertical broken lines indicate transitions in a clock signal of a data clock belonging to the data signal. The period of the data clock, also called channel bit period, is indicated by the T. When this data signal is recorded, a 'high' period 11 is recorded as a mark having a length corresponding to the duration of the period 'high' 11, and a 'low' period 12 is recorded as an unwritten area, a space, between the marks and having a length corresponding to the duration of the 'low' period. In general, the length of a mark is substantially equal to the number of channel bit periods of the write speed data signal times. Therefore, the length of a mark is often expressed by a number of data clock periods when the corresponding data signal is 'high' (eg 6T for a mark with a corresponding data signal that is 'high'). for 6 data clock periods, and 2T for a mark with a corresponding data signal that is 'high' for 2 data clock periods). The data is written to an optical recording carrier comprising an information layer having a phase that is reversibly switchable between a crystal phase and an amorphous phase (i.e., a phase change layer). The marks representing the data are written along a track in the information layer upon irradiating the information layer with a pulse radiation beam. The marks are areas of the information layer that have optical characteristics that are different from what surrounds them, which makes possible the optical reading of these marks.

Figure 1 b shows a control signal 20 corresponding to the data signal 10 in a first characterization of the invention. The control signal 20 is used to modulate the power of a beam of radiation with which the marks are being written into the information layer, where it is assumed that the power level of the radiation beam is proportional to the signal level of the signal. control. Figure 1 b shows two pulse sequences to subsequently write a 6T mark and a 2T mark. Each pulse sequence begins with a cooling pulse 27 that has a cooling power level (c) 17. The power level ".jH- t. '' SS¿ii». ^ > ..t ^ »< ^. > ** - - tel??? i i ^ ^ ^ ^ ^ ^ ^ ^ ^ »» »» »». jfcfcifeJ »aa.A». > ^ L. "J ^ nánSajrifchSae» »between the sequences is at an erase power level (e) 16. The power level between the write pulses 21, 22 and 23, with the write pulses having a level of writing power 14, is at the cooling power level (c) 17. The last write pulse of a sequence 23 is directly followed by a rear heating pulse 24 having a rear heating power level (r) 15, and the first write pulse of a sequence 22 is directly preceded by a front heating pulse 25 having a front heating power level (f) 13. When recording a 2T mark, only a single write pulse 26 is applied, said only write pulse 26 being the first write pulse in the sequence and the last write pulse in the sequence at the same time.

In a preference characterization! of the invention, the level of power of * rear heating (r) and the level of frontal heating power (f) are made dependent on the length of the marks to be recorded. Figure 2 shows a first control signal 31 corresponding to a first data signal 30 and a second control signal 33 corresponding to a second data signal 32 in this preferential characterization of the invention.

Figure 2a shows a data signal 30 successively comprising a 2T mark and a 3T mark to be recorded. Figure 2b shows the corresponding control signal 31. The front heating pulse 252 of the pulse sequence for recording a 2T mark has a first front heating power level (f1) 342, while the front heating pulse 253 of the pulse sequence for recording a 3T mark has a second level of front heating power (f2) 341. Figure 2c shows a data signal 32 which again comprises the ^ ziákmiS & a? *. 2T brand now followed by a 4T brand to be recorded. Figure 2d shows the corresponding control signal 33. The rear heating pulse 242 of the pulse sequence for recording a 2T mark has a first level of rear heating power (r1) 351, while the rear heating pulse 244 of the pulse sequence for recording a 4T mark has a second level of rear heating power (r3) 352. In this example, the rear heating pulse 242 of the pulse sequence for recording a 2T mark has a rear heating power level that is equal to that of the pulse of rear heating 243 of the pulse sequence to record a mark of 3. However, the rear heating pulse 242 of the pulse sequence for recording a 2T mark may alternatively have a rear heating power level that is different of the one having the rear heating pulse 243 of a pulse sequence to record a 3T mark. Likewise, the frontal heating power level of the frontal heating pulse 253 for recording a 3T mark may alternatively have a value that is different from that of the front heating power level of the frontal heating pulse 254 for record a 4T brand, although these have an equal value in this example. The example shown in Figure 2, the marks having a length greater than 4T will be recorded by using a frontal heating pulse having a frontal heating power level which is the same as that used to record a 4T mark and the Use a rear heating pulse that has a level of rear heating power that is equal to that used to record a 4T mark. It may be apparent to a person skilled in the art that marks that are longer than 4T may be recorded alternatively, using front heating power levels and rear heating power levels that are optimized for each individual brand length. In addition the level of rear heating power (r) and the level of frontal heating power (f), also the cooling power level (c) of the cooling pulse may depend on the length of the marks to be recorded . Figure 3a shows a data signal 40 successively comprising a 2T mark and a 3T mark to be recorded. Figure 3b shows the corresponding control signal 41. The cooling pulse 271 of the pulse sequence for recording a 2T mark has a first level of cooling power (d) 44, while the cooling pulse 272 of the pulse sequence for recording a 3T mark has a second level of cooling power (c2) 45.

Figure 4 shows a characterization of the invention where the rear heating pulse includes a front portion and a rear portion. Figure 4a shows a data signal 50 comprising a 3T mark to be recorded. Figure 4b shows the corresponding control signal 51. The last write pulse of a sequence 23 is directly followed by a front portion 54 of the rear heating pulse, which has a rear heating power level (r) 15, and subsequently a rear portion 55 of the rear heating pulse. The rear portion 55 of the rear heating pulse has a power level 53 that is less than the cooling power level (e) 16.

Figure 5 shows a recording device according to the invention for recording data on a disk-shaped optical recording carrier 150. Alternatively, the recording carrier may have the shape of a cassette. An SD data signal, comprising the information to be recorded in the form of marks, is connected jsaSS < ? mm? í &&iii: < . ? > -mUMBuaaMtaAWMto », to a control unit 60. A current source 61 inside the control unit 60 has five outputs, A, B, C, D, and E. Output A provides a current which, when fed to a radiation source 151, through a control signal So will result in a radiation beam 152 having a level of erasing power (3). Likewise, outputs B, C, D and E provide currents that result in the writing power level, the rear heating power level (r), the front heating power level (f) and the level of cooling power (c), respectively. The current of each output A, B, C, D and E can be selected by a change unit 6. The change unit 62 is operated by a pattern generator 63 controlled by an SD data signal and a SK clock signal . The pattern generator 63 transforms the SD data signals into pulse sequences having a cooling power level (c), a writing power level, a front heating power level (f), a power level of rear heating (r) and a level of erasing power (e) according to a desired pattern. The clock signal S? it is obtained from a clock generator 158. When a recording device is used to write at a single speed, the clock generator 158 is pre-programmed at a fixed frequency. When written at a variable speed, the frequency of the clock generator 158 will vary with the actual write speed. The control signal Sc, provided at the output of the control unit 60 and carrying out the write pulse sequences, is connected to the radiation source 151. The control signal The power of the radiation beam is controlled 152 generated by the radiation source 151. the radiation beam 152 is focused by a lens 153 on an information layer 501 of the recording carrier 150. The disc-shaped recording carrier 150 is rotated about its center by a motor 154.

This characterization of a recording device according to the invention is suitable for executing the characterizations of the method according to the invention as shown in Figure 1, using a single level of frontal heating power (f) and a single level of Rear heating power (r) that are independent of the length of the marks to be engraved.

Figure 6 shows a recording device according to the invention for recording on a disk-shaped optical recording carrier 150, using value for the front heating power level (f) and the rear heating power level (r). ) that depend on the length of the marks to be recorded. The data signal SD is connected to a unit 70 comprising determination means. This unit 70 analyzes the data signal So and determines the length of the marks to be recorded. Depending on the length of a mark to be recorded, the appropriate current determination for the outputs C (rear heating power level) and D (front heating power level) of a current source 61 are selected and transferred to the current source 61 through signal 71. In this way, instead of a single current, which results in a single power level of the radiation beam, both outputs C and B can supply different currents, resulting in different levels of power of the beam of radiation, the value of the currents is dependent on the length of the marks to be recorded.

In addition to depending on the length of the marks to be recorded, the level of frontal heating power (f) and the level of rear heating power (r) may also depend on the properties of the recording medium. The information concerning the optimum determination of the power levels for a specific recording carrier in which the data will be recorded can be supplied to the unit 70 by the signal 72. The information concerning the optimal determination of the levels of power can be supplied, for example, by a test procedure that determines the optimal determination or, alternatively, can be read directly from an area that contains recording parameters in the recording carrier.

Claims (25)

1. CHAPTER CLAIMING Having described the invention, it is considered as a novelty and, therefore, the content is claimed in the following: 5 CLAIMS 1. A method of recording marks representing data on a recording medium, said recording medium comprising an information layer having a phase that is reversibly switchable between a crystal phase and an amorphous phase, upon irradiating to the information layer with a pulse radiation beam, each mark is written by a sequence of pulses comprising at least one write pulse, the written marks are erasable when irradiating the information layer with a beam of radiation that has a level of erasing power (e), a first write pulse of a sequence of pulses that are preceded by a cooling pulse that has a level of cooling power (c) that is less than the level of erasing power (e), said beam of radiation is generated by a source of radiation, characterized in that a last pulse of writing of a sequence is directly followed by a pulse of rear heating having a rear heating power level (r), the rear heating power level (r) being greater than the level of erasing power (e).
2. 2. A method as claimed in claim 1, characterized in that the level of rear heating power (r) of the rear heating pulse depends on the properties of the recording medium.
3. 3. A method as claimed in claim 1, for recording marks having lengths of nT, where T represents the length of a period of a clock of faaaBtifcsh •, .. «tafet. Referring to a data signal and n representing a predetermined natural number greater than 1, each mark is written by a sequence of (n-1) write pulses, characterized in that the rear heating pulse has a first level of rear heating power (r1) when n = 2, a second level of rear heating power (r2) when n = 3, and a third level of rear heating power (r3) when n > 4, the first level of rear heating power (r1), the second level of rear heating power (r2) and the third level of rear heating power (r3) depend on the properties of the recording medium.
4. 4. A method as claimed in claim 1, 2 or 3, characterized in that the first pulse of a sequence is directly preceded by a frontal heating pulse having a frontal heating power level (f), the frontal heating pulse it is directly preceded by the cooling pulse having a cooling power level (c), the frontal heating power level (f) being greater than the erasing power level (e).
5. 5. A method as claimed in claim 4, characterized in that the front heating power level (f) of the frontal heating pulse depends on the properties of the recording medium.
6. 6. A method as claimed in claim 4 for recording marks having lengths of nT, where T represents the length of a period of a reference clock in a data signal and n represents a predetermined natural number greater than 1, each mark is written by a sequence of (n-1) write pulses, characterized in that the heating pulse has a first level of frontal heating power (f1) when n = 2, a second level of frontal heating power (f2) when n = 3, and a third level of frontal heating power (f3) when n > 4, the first level of frontal heating power (f1), the second level of frontal heating power (f2) and the third level of frontal heating power (f3) depend on the properties of the recording medium.
7. 7. A method as claimed in claim 1, 2, 3, 4, 5, or 6 characterized in that the level of cooling power (c) of the cooling pulse depends on the properties of the radiation source and the recording medium .
8. 8. A method as claimed in claim 4 for recording marks having lengths of nT, where T represents the length of a period of a reference clock in a data signal and n represents a predetermined natural number greater than 1, each mark is written by a sequence of (n-1) writing pulses, characterized in that the cooling pulse has a first level of cooling power (d) when n = 2, a second level of cooling power (c2) when n = 3 , and a third level of cooling power (c3) when n > 4, the first level of cooling power (d), the second level of cooling power (c2) and the third level of cooling power (c3) depend on the properties of the radiation source and the recording medium.
9. 9. A method as claimed in claim 1, 2 or 3, characterized in that the rear heating pulse includes a front portion having a rear heating power level (r), and a rear portion having a power level which is less than the erase power level (e).
10. 10. A method of recording marks that represent data in a recording medium, said recording medium comprises an information layer having a phase that is reversibly changeable between a crystal phase and an amorphous phase, by irradiating the layer of information wa pulse radiation beam, each mark has a length of nT, where T represents the length of a period of a reference clock in a data signal and n represents a predetermined natural number greater than 1, the marks that are written by a sequence of pulses comprising (n-1) write pulses, the written marks are erasable by irradiating the information layer wa beam of radiation having a level of erasing power (e), a first write pulse of a sequence of pulses that are preceded by a cooling pulse that has a cooling power level (c) that is lower than the erasing power level (e), said radiation beam is generated p or the source of radiation, characterized in that the cooling pulse has a first level of cooling power (d) when n = 2, a second level of cooling power (c2) when n = 3, and a third level of power cooling (c3) when n > 4, the first level of cooling power (d), the second level of cooling power (c2) and the third level of cooling power (c3) depend on the properties of the radiation source and the recording medium.
11. 11. A method as claimed in claim 10, characterized in that the first level of cooling power (d) is substantially equal to the second level of cooling power (c2) and the third level of cooling power (c3).
12. 12. A recording device for recording data in the form of marks in a recording medium, said recording medium comprises a layer of information that has fcdtffcfe «ttBm ^ h? a phase that is reversibly changeable between a crystal phase and an amorphous phase, upon irradiating the information layer wa beam of pulsed radiation, the etched marks are erasable by irradiating the information layer wa beam of radiation having a level of erasing power (e), the device comprises a radiation source that provides the radiation beam and a control unit to control the power of the radiation beam, the control unit is operated for providing a sequence of writing pulses to write a mark and controlling the power of the radiation beam such that it has the level of cooling power (c) which is less than the level of erasing power (e) preceding a first pulse of writing a sequence of pulses, characterized in that the control unit is operated to control the power of the radiation beam in such a way that it has a back heating pulse having a level of po After the rear heating curve (r) which * 'directly follows a last pulse of a sequence, the rear heating power level (r) is greater than the level of erasing power (e).
13. 13. A recording device as claimed in claim 12, characterized in that the recording device comprises means for determining a value for the rear heating power level (r), whose value for the rear heating power level (r) it depends on the properties of the recording medium.
14. 14. A recording device as claimed in claim 12 for recording marks having lengths of nT, where T represents the length of a period of a reference clock in a data signal and n represents a predetermined natural number greater than 1, characterized in that the engraving device comprises means for determining a first value for the rear heating power level (r1) when n = 2, a second value for the rear heating power level (r2) when n = 3, and a third value value for the rear heating power level (r3) when n > 4, said first value level for the rear heating power level (r1), second value for the rear heating power level (r2) and third value for the rear heating power level (r3) depend on the properties of the recording medium.
15. 15. A recording device as claimed in claim 12, 13, or 14 characterized in that the control unit is operated to control the power of the radiation beam in such a way that it has a frontal heating pulse having a power level frontal heating (f) which directly precedes a first writing pulse and a cooling pulse having a cooling power level (c) that directly precedes the frontal heating pulse, the frontal heating power level (f) being greater than the erasing power level (e) and the cooling power level (c) being less than the erasing power level (e).
16. 16. A recording device as claimed in claim 15, characterized in that the recording device comprises means for determining a value for the front heating power level (f), whose value for the front heating power level (f) it depends on the properties of the recording medium.
17. 17. A recording device as claimed in claim 15 for recording marks having lengths of nT, where T represents the length of a period of a reference clock in a data signal and n represents a predetermined natural number greater than 1, characterized in that the recording device comprises ¡ß im aiiimitit, means to determine a first value for the front heating power level (f1) when n = 2, a second value for the front heating power level (f2) when n = 3, and a third value for the frontal heating power level (f3) when n > 4, said first value for the front heating power level (f1), second value for the 5 front heating power level (f2) and third value for the front heating power level (f3) depend on the properties of the recording medium.
18. 18. A recording device as claimed in claim 15, characterized in that the recording device comprises means for determining a 10 value for the cooling power level (c), whose value for the cooling power level (c) depends on the properties of the recording medium.
19. 19. A recording device as claimed in claim 15 for recording marks having lengths of nT, where T represents the length of a period of one 15 reference clock in a data signal and n represents a predetermined natural number greater than 1, characterized in that the recording device comprises means for determining a first value for the cooling power level (d) when n = 2, one second value for the cooling power level (c2) when n = 3, and a third value for the cooling power level (c3) when n > 4, said first value for the 20 level of cooling power (d), second value for the level of cooling power (c2) and third value for the level of cooling power (c3) depend on the properties of the radiation source and the recording medium.
20. 20. A recording device as claimed in claim 12, 13, or 14 characterized in that the control unit is operated to provide the pulse of te ^^ fe ^ S »fe ^ A ^^ ii ^^" JMgis "Aá¿ ^^^ fe ^ g¿.J¡ rear heating and control the power of the radiation beam in such a way that the rear heating pulse include a front portion having a rear heating power level (r), and a rear portion having a power level that is less than the erasing power level (e).
21. 21. A recording device for recording data in the form of marks on a recording medium, said recording medium comprises an information layer having a phase that is reversibly changeable between a crystal phase and an amorphous phase, and said markings having lengths of nT, where T represents the length of a period of a reference clock in a data signal and n represents a predetermined natural number greater than 1, when irradiating the information layer with a beam of pulse radiation, the recorded marks are erasable by irradiating the information layer with a radiation beam having a level of erasing power (e), the device comprises a radiation source that provides the radiation beam and a control unit to control the power of the radiation beam, the control unit is operated to provide a sequence of writing pulses to write a mark and control the power of the beam of radiation. such that it has the level of cooling power (c) that is less than the level of erasing power (e) that precedes a first pulse of writing a sequence of pulses, characterized in that the recording device comprises means for determining a first value for the cooling power level (d) when n = 2, a second value for the cooling power level (c2) when n = 3, and a third value for the cooling power level (c3) when n > 4, said first value for the cooling power level (d), second value for the cooling power level (c2) and third value for the cooling power level (c3) depend on the properties of the radiation source and the recording medium. '^^^^^^^^^^^^^^ ^^^^^^^^^^^^^^
22. 22. A recording device as claimed in claim 21, characterized in that the first value for the cooling power level (d) is substantially equal to the second value for the cooling power level (c2) and the third value for the level of cooling power (c3).
23. 23. A recording medium for use in a recording device as claimed in claim 13 or 14, said recording medium comprises an information layer having a phase that is reversibly switchable between a crystal phase and an amorphous phase , and comprising an area containing recording parameters, characterized in that the area containing recording parameters comprises a value for the rear heating power level (r).
24. 24. A recording medium for use in a recording device as claimed in claim 16 or 17, said recording medium comprises an information layer having a phase that is reversibly switchable between a crystal phase and an amorphous phase , and comprising an area containing recording parameters, characterized in that the area containing recording parameters comprises a value for the frontal heating power level (f).
25. 25. A recording medium for use in a recording device as claimed in claim 18 or 19, said recording medium comprises an information layer having a phase that is reversibly switchable between a crystal phase and an amorphous phase , and that includes an area that contains parameters of recording, characterized in that the area containing recording parameters comprises a value for the cooling power level (c). s ^^ s ^^^ h ^ ikx ^^^.