MXPA99007261A - Method and device for writing optical record carriers - Google Patents

Abstract

A method is described for optimizing recording conditions for writing information on an optical record carrier. The information is written on the record carrier in the form of optically detectable marks, each mark being written by a pulse series of radiation. A series of test patterns is written on the record carrier (1) for the optimization. A jitter detector (11) measures both the leading-edge and trailing-edge jitter of the read signal. The leading-edge jitter is used to optimize the value of a parameter influencing only the leading part of a pulse series. The trailing-edge jitter is used to optimize a parameter influencing only the trailing part of the pulse series.

Description

METHOD AND DEVICE FOR WRITING ON CARRIERS OF OPTICAL RECORDS The invention relates to a method and a device for writing user information on an optical record carrier. The marks representing the user information are written on a recording layer sensitive to the radiation of the record carrier by means of a series of radiation pulses. The series of pulses comprises one or more pulses. Before registering the user information on a record carrier, a test pattern is written on the record carrier. The read signal obtained from this pattern provides information to optimize the registration process, in particular the shape of the series of pulses. The user's information is subsequently written on the record carrier with the optimized process. The European patent no. 0 669 611 describes such a method and device for optimizing the writing power of the series of pulses. The known device writes a test pattern on the record carrier, the test pattern consists of a series of subpatterns, each subpattern is written with a different radiation power. Subsequently, the fluctuation of each read signal corresponding to each subpattern is measured. The power of registration is fixed in the value where the fluctuation curve versus power or energy shows a minimum fluctuation. The fluctuation of a data signal is a measure of the deviation between the position of the ends and edges descending and / or rising of the data signal and the corresponding transitions of a clock signal, possibly recovered from the signal ends of the signal. data. The deviation can be normalized over the duration of a period of the clock signal. However, the known method does not always provide the optimal registration conditions, in particular when exchanging record carriers and device from different manufacturers. It is an object of the invention to provide a recording device and method with an improved adaptation of the registration conditions to the combination of a particular recording device and carrier. The object is achieved when the device according to the invention comprises recording means for writing a pattern of optically readable marks on the record carrier, irradiating the record carrier with a series of radiation pulses, a mark that is formed by a series of pulses, a generator of a test signal to generate a test signal comprising a test pattern and supplying the test signal to an input of the means register, reading means for reading the markings on the record carrier and supplying a read signal, a jitter detector for measuring the fluctuation of the reading signal corresponding to the test pattern and supplying a signal for jitter of the edge end front and a rear edge end jitter signal, control means for supplying a first control signal and a second control signal depending on the jitter signal of the front and rear ends, respectively, the values of the control signals correspond to an optimum quality of the read signal, processing means for converting the input information to be recorded in an output signal supplied to the recording means, the output signal corresponds to the series of radiation pulses and represents the input information, the series of pulses has a front part and a back part, an optimal value of u The first parameter related to the front part is determined by the first control signal and / or an optimum value of a second parameter related to the rear part is determined by the second control signal. It has turned out that a known device is not always able to find the optimal recording conditions, because it uses the total fluctuation, that is, the combined fluctuation of both ends or front edges. and rear of the read or reading signal. When the fluctuation of the leading edge and rear edge are determined separately, it is possible to further improve the registration conditions. Since the fluctuation of the leading end is a measure of accuracy of the position of the leading end of a mark written on the recording layer, the fluctuation of the measured leading end is preferably used to influence this position. The position of the front end of a mark can be influenced by varying a first parameter of the front part of the series of pulses used to write the mark. Likewise, the fluctuation of the rear end is a measure of the accuracy of the position of the rear end of a written mark, and the fluctuation of the rear end is preferably used to optimize a second parameter of the rear part of the series of pulses. It is said that registration conditions are optimal if the number of errors in the retrieval of information recorded under these conditions is minimal. In general, the information is represented on the record carrier by a set of different marks. If, for example, the information is coded according to the so-called EFM, the set will comprise marks that have lengths of 3, A,. . . 11 times a unit of length and is possibly a synchronization mark of 14 units of length. A mark that has a length of n times the unit of length is known as a nT mark. A single mark outside the set of different marks is written by a series of pulses from a corresponding set of different impulse series. The length of the series of impulses increases with the length of the mark to be written that also increases. In the optimization method according to the invention, the front part of at least one series of pulses of the entire series of pulses is optimized; likewise, the rear part of at least one series of pulses in the assembly was optimized. Both the front and rear of a series of pulses can be optimized according to the invention. Preferably, the front part of the short pulse series is optimized, while the rear part of the series of long pulses is optimized. The front and back of the series of pulses of intermediate length can be optimized. The cessation between the short and long impulses should be closer to the series of shorter pulses than to the longer ones, because the relative change in the length of the longer written marks is greater for the shorter marks than for the shorter ones. the longest brands. The cessation of the information encoded by EFM is preferably in the series of pulses T4 or T5. The optimization of the separation of impulses of different Lengths provides a very suitable method to improve registration conditions. The first or second parameter to be optimized can be the radiation power of the front or rear of the series of pulses, respectively. A series of pulses may comprise one or more radiation pulses. When a series of pulses has two or more pulses, the first or second parameters may be the impulse widths of an impulse in the front or rear of the series of pulses, respectively. Alternatively, the first and second parameters may be a duration of time between two pulses in the front or rear of a series of pulses. A combination of different parameters is also possible for the front and rear, for example, the radiation power of the front part and a pulse width of the rear part. In a preferred embodiment of the device, the first parameter is the power of the front part and the second parameter is the power of the rear pulse in a series of pulses. The device according to the invention preferably adjusts or sets the power of the series of pulses to an optimum value depending on the measured total amplitude or fluctuation of the reading signal corresponding to a registered test pattern. The power is applied to those parts of the impulse series where the Power is not affected by the first or second parameter. The measured amplitude can be converted to a modulation or a so-called asymmetry of the measured signal to set the power. The parameter to be optimized first in the method according to the invention should be the parameter which affects the other parameters more strongly. A preferred order for determining the optimal recording conditions is to first write a test pattern with variable values of the first parameter, for example, the power of only the front part of the series of pulses. The optimum value of the first parameter is determined from this pattern by measuring the fluctuation of the forward end of the measured signal and determining the value of the first parameter that corresponds to the minimum fluctuation. A second test pattern is recorded using the optimum power and the optimum value of the first parameter and varying the value of a second parameter, e.g., the power of the rear pulse of a series of pulses. The optimum value of the second parameter is determined from the fluctuation of the rear end of the read signal. The two steps of the above optimization are preferably preceded by a step to optimize the write power of those parts of the series of pulses that are not affected by the two previous steps. So far a test pattern with values is written variables of the writing power of the series of pulses on the record carrier and an optimal writing power is determined from the read signal corresponding to that pattern. This writing power can be used when writing the first and second test patterns. After the two previous steps, a fourth test pattern can be recorded using the optimum values of the first and second parameters and varying the power of the series of pulses over a small interval around the optimum value found in the first step. The optimum value of the power is determined from the amplitude of the read signal. A further aspect of the invention relates to a method for recording information about an optical record carrier, which comprises the step of determining the optimal recording conditions according to what is described for the recording device according to the invention. A further aspect of the invention relates to a method for recording information on a record carrier in the form of marks of different lengths, the mark is formed by irradiating the record carrier with a series of radiation pulses, each series of pulses having a front part, a middle part and a back part, each series of impulses belongs to a set of series of impulses that has different lengths, the set of series of pulses comprises a subset of the series of short pulses and a series subset of long pulses, characterized in that the series of pulses of only one of the subsets has a front and a middle part, which differ in a first parameter, and because the series of pulses between the other subsets has a middle part and a back part, which differ in a second parameter. The two subsets can be partially superimposed, that is, one or more series of pulses belong to both subsets. The two subsets can also be disjunctive, and not all the series of impulses need to be included in the two subsets. A subset comprises at least one series of pulses, but preferably two or more. A further aspect of the invention relates to a method for recording information on a record carrier in the form of marks of different lengths, a mark being formed by irradiating the record carrier with a series of radiation pulses, each series of pulses has a front part and a back part, each series of pulses belongs a set of series of pulses having different lengths, the set of series of pulses comprises a first subset of series of short pulses and a second subset of series of pulses. long pulses, characterized in that the series of pulses of the first subset has a first value of a first parameter in the front and the series of pulses of the second subset has a second different value of the first parameter in the front, and because a series of impulses of the first subset have a first value of a second parameter in the rear part and the series of pulses of the second set having a second value different from the second parameter of the rear part. The registration method according to the invention has been shown to improve the quality of the records and significantly reduce the fluctuation of the signal read from the recorded information. The influence of the trademark of the registration bearer and the registration device on the quality of the registration is reduced. In particular, the quality of the record is less sensitive to the wavelength of the radiation and the filling of the objective lenses of the recording device. The objects, advantages and features of the invention will be apparent from the following more particular description of the preferred embodiments of the invention, as illustrated in the accompanying drawings, in which Figure 1 is a diagram of an optical recording device according to the invention, Figure 2 is a diagram of a jitter detector, Figure 3 shows a digital information signal, a signal corresponding to the power of radiation for writing and a sequence of corresponding states, Figure 4 is a diagram of the means for processing information, and Figure 5A and B illustrate two signals that correspond to the radiation power for writing. Figure 1 shows a device and an optical record carrier 1 according to the invention. The record carrier 1 has a transparent substrate 2 and a recording layer 3 arranged on it. The recording layer comprises a material suitable for writing information by means of a beam of radiation. The recording layer can be, for example, the magneto-optical type, the phase change type, the dye type or any other suitable material. The invention is applicable to any of those means, but has been shown to be particularly suitable for dyeing media. The information can be recorded in the form of optically detectable regions, also called marks, on the recording layer 3. The device comprises a radiation source 4, for example, a semiconductor laser, for emitting a beam of radiation 5. The beam of The radiation is made to converge on the recording layer 3 via a beam splitter 6, an objective lens 7 and a substrate 12. The record carrier can also impinge on the air, where the radiation beam strikes directly on the recording layer. 3 without passing through a substrate. The reflected radiation of the medium 1 is made to converge by means of the objective lens 7 and, after passing through the beam splitter 6, it falls on a detection system 8, which converts the incident radiation into electrical detector signals. The detector signals are fed to a circuit 9. The circuit derives various signals from the detector signals, such as a read signal SRI representing the information being read from the medium 1. The radiation source, the beam splitter 6 , the objective lens 7, the detection system 8 and the circuit 9, together form the reading means 10. In an alternative embodiment, the beam splitter 6 is a diffraction grating, and the detection system 8 is arranged by of the radiation source 4. The read signal S_u of the circuit 9, is processed in a first processor 11 to derive signals representing one or more read parameters, for example, a modulation, asymmetry or fluctuation, of the read signal. The signals are used to control the registration process. The signals are fed into the control means 12, which they process a series of values of the read parameters, and based on them they derive values of the control signals Sc that correspond to the optimal recording conditions. The control signals are supplied to the main processor means 13, for example, a microprocessor. The processor 11 and the control means 12 can be suitable circuits for processing analog signals or circuits suitable for processing digital signals. A second read signal SR2, which may be the same as the signal SR ?, supplied by the circuit 9, is also fed to the main processing means 13, which process the signal to form an information output signal Sj0, which represents the read information of the record carrier 1. The main processor means 13 controls a test signal generator 14, which supplies a test signal St to a driver of the radiation source 15 during the test phase preceding the registration of the information. The exciter of the radiation source 15 generates an exciting signal for the radiation source 4, depending on the fed signal. The test signal corresponds to a pulse pattern of the radiation emitted by the radiation source 4. The exciter of the source 15, the radiation exciter 4, the beam splitter 6, and the objective lens 7, together form the means of registration 17.

An information input signal Su, which represents the information of the user to be registered on the carrier 1, is also fed to the main processor means 13. The processor means 13, synchronization, address and error correction can be added to the information of the user. The processed information represented by the signal S? P is supplied to the processor means 16. Control signals Sc are also supplied to the processor means 16. The processor means 16 generates an SD signal to control the exciter of the radiation source 15 when information is recorded. It uses the control signals to adjust the exciter signal for an optimal registration process. The radiation pulses emitted by the radiation source 4 induce marks in the form of changes detected optically in the recording layer 3. Such a mark can be written by a single radiation pulse. A mark can also be written by a series of radiation pulses of equal or different lengths. The actual power of the radiation emitted by the radiation source 4 can be measured by a power detector not shown, arranged in a side lobe, in other circumstances not used, of the radiation beam or in the reflected radiation of an element in the optical path of the radiation beam. The detector signal power can be directly connected to the main processor means 13. The first processor 11 comprises means for deriving a read parameter from the read signal. The read parameter can be a parameter related to the amplitude of the read signal, such as modulation or a combination of the modulation of the high and low frequency components in the read signal. The read parameter can also be a parameter related to the synchronization of the transitions in the read signal, such as fluctuation. The processor 11 may comprise means for deriving more than one parameter from the read signal. According to the invention, the processor 11 comprises a fluctuation detector 20 for measuring the fluctuation of both front and rear ends of the read signal SRI. Figure 2 shows a jitter detector mode 20. The read signal SR_ is supplied to a phase detector 21, which measures the phase between the read signal and a clock signal SCL- A low pass filter 22 removes the components High frequency of the measured phase. The output of the low pass filter 22 is used to control the frequency of a clock generator 23. The clock generator provides the clock signal SCL. which is fed back to the phase detector 21. The components 21, 22 and 23 form a closed loop per phase, which it drifts a clock signal from the read signal. The clock signal SC and the signal read SR? they are supplied to a first time interval detector 24, which measures the time intervals between the forward ends of the read signal and the closest transitions of the clock signal. The front end is that part of the signal read SR? which corresponds to the first part of a mark detected by the scanning radiation beam, while the rear end is that part corresponding to the last part of the mark. The clock signal SC and the signal read SR? they are supplied to a second time interval detector 25, which measures the time intervals between the rear ends of the read signal and the closest transitions of the clock signal. The time intervals measured by the time interval detector 24 and 15 are analyzed in a circuit 26 and 27, respectively. Circuits 26 and 27 process the values of the time interval to form an average value, a standard deviation and / or a peak deviation. In the mode of the fluctuation detector according to the invention, the circuits 26 and 27 generate signals SLJ and STJ representing the standard deviation of the fluctuation of the leading end and the fluctuation of the trailing end, respectively. The processor means 16 generates an SD output signal in response to the information signal S? E and they supply the exciter of the radiation source 15. Figure 3 shows in the upper trace, a part of an information signal coded by EFM, to the double value, S? P as a function of time t. The signal shows a pulse of 3T, 4T and 6T as a sequence of logical values "0" and "1", with transitions between the values that occur at clock moments at a distance T. The second trace in Figure 3 shows an example of a series of three pulses of an SD output signal belonging to the three signal pulse shown in the first trace and optimized according to the invention. The second trace indicates the radiation power of the source 4 corresponding to the value of the SD signal. Pb is an insufficient deviation power level to write a mark on the record layer. Pw is a writing power level of the middle part of the series of pulses. Pw_ is a writing power level from the front to a series of pulses. Pw2 is a power from the back of a series of pulses. The third trace shows the logical states of each period of clock of duration T. In the example of SD shown in the second trace, the values of the signal can change in clock moments at a distance of T / 3. The first impulse of a series of impulses has a width of 4/3 T, the subsequent impulses in the series of impulses have a width of 2/3 T and a separation between the impulses of 1/3 T. The front part of a series of impulses in this example has a length of 1/3 T, the rear has a length of 2/3 T. The middle part of the series of pulses has a length equal to the total length of the series of pulses minus 1T. The fourth trace in Figure 3 shows schematically the marks formed by the series of pulses of the second trace: a mark of 3T, 4T and 6T 28a, 28b and 28c respectively and unwritten areas, intermediate, 29a and 29b, of 3T and 4T of length respectively. In the example of the signal optimized in the second trace of Figure 3, the power Pw_ in the front of the subset of the series of short pulses (3T and 4T) is optimized using the fluctuation of the forward end, while the power in the front of the series of longer pulses (nT with n> 5) is set to a level of P ". The power of the rear of the 3T pulse series is used and fixed to the Pw level, while the power Pw2 of the rear of the subset of the longer pulse series (nT with n> 4) is optimizes using the rear end fluctuation. It should be clear that the invention is not limited to the anterior lengths of the front and rear of the series of pulses, and that different lengths of the front and rear portions of the series of pulses are possible. Similarly, it should be clear that the invention it is not limited to the particular selection shown in the series of pulses, from which the front and rear are optimized. Figure 4 shows a mode of processor means 16 generating an output signal SD shown in the second trace of Figure 3, in response to the SIP information signal shown in the first trace of Figure 3. A clock signal Fc which has a period of T is supplied to a closed loop per phase 30. The output frequency FC3 of the closed loop per phase is divided by a factor of 3 by means of a divider 31 and then fed back to the closed loop per phase 30. The combination of the closed loop by phase 30 and the splitter 31 operates as a frequency triplicator, which generates a clock signal Fc3 having a period of 1/3 T. The SIP information signal is supplied to a deviation register of SIP. eight bits 32. The input bits of the S_p are fed to the register at a rate of one bit per clock period T. The content of the register is supplied to a state machine 33 once each clock period T. The machine of state converts each 8-bit word in the register into three consecutive power values. The power values are distributed at an output of the state machine at a rate of one value per period of 1/3 T. Accordingly, three power values are provided per clock periods T. The power values are converted from the digital format to the analog format by means of a DA 34 converter, which supplies an SD analog output signal, to be used in the exciter of the source 15. The operation of the State machine will be explained with reference to table I.

Table I The table shows the bit pattern received by the state machine 33 of the deviation or shift register 32, the corresponding state of the state machine and the three consecutive power values belonging to that state. The states belonging to the SIP information signal in the first trace of Figure 3 are indicated in the lower trace of Figure 3. There are two patterns of input bits that lead to the state 0 and two that lead to the state 1. bit further to the right of each bit pattern is the last bit of information entered in a deviation or shift register 32. The fourth bit on the right is the current bit. Each bit in the table can have the logical values "0" and "1" and in the so-called value "0" or "1" "without care", indicated by an "x". As an example, if at the instant of the clock the state machine Fc 33 has a bit pattern "xllllOxx", it enters state 3; in response, it provides in three consecutive clock moments of Fc3 the power values Pw, Pw2 and PW2. in this order. These digital power values are converted from digital to analog and supplied to the driver of the source 15. Before writing the information about the record carrier 1, the device advances to a test phase in which it fixes the power of the radiation of the series of pulses used to write to an optimal value, performing the following procedure. The device writes a first test pattern on the record carrier 1, comprising a series of subpatterns, each of which has a different write power. Subsequently the subpatterns can be written with the same incremental writing power under the control of the main processor means 13. The lengths of the marks in the subpattern should be selected to give a desired read signal. If the maximum modulation of the read signal is to be determined, the subpatterns should comprise sufficiently long marks to achieve a maximum modulation of the read signal. When the information is coded according to the so-called EFM modulation, the test pattern preferably comprises marks with a length In. The patterns can be written anywhere on the medium. They can also be written in test areas provided especially on the medium. The signal SR_ corresponding to the first test pattern is processed by the processor 11 and a first read parameter of the read signal is derived. The read parameter can be the modulation of the read signal. The first parameter read is preferably the asymmetry of the read signal, called ß, which is a measure of the difference between the average value of the signal read taken over the information bandwidth and the average value of the components of the signal read near the low frequency end of the bandwidth. Can a signal representing the asymmetry be obtained by passing the read signal SR? through a high-pass filter, determining the values of signal Al and A2 of the upper and lower envelope of the filtered signal, respectively, and calculating β = (A1 + A2) / (A1-A2) where, in general , A2 will have a negative value. The control means 12 receives from the processor 11 the values of ß for all the subpatterns in the first test pattern. The values of ß and the writing powers of the corresponding subpatterns of a curve of ß versus writing power, which is a line that crosses the axis in ß = 0. The control means 12 determines the writing power for which ß has a value close to or equal to zero, preferably in a range of -0.05 to +0.15. The selected optimal writing power is supplied to the main processor means 13. In the second step of the test phase, the device optimizes the front of the series of pulses used for writing. For this purpose, the signal generator 14 generates a test signal to write a second test pattern on the record carrier, using the optimum writing power obtained in the first step. The second test pattern controls a it would be subpatterns with different power values in the front of the series of pulses. The processor 11 measures the fluctuation of the forward end SL of the read signal corresponding to each subpattern and supplies the fluctuation values of the control means 12. The control means 12 uses the fluctuation values of the leading end of the subpatterns for determine the power of the front end Pl that gives the lowest fluctuation of the front end. The control signal representing this value is supplied to the main processor means 13. In the third step of the test phase, the device optimizes the back of the series of pulses used to write. The device writes a third test pattern, using the series pulses with the writing powers for the back pulses that have different values in the different subpatterns of the third test pattern. The series of pulses applies the optimum forward edge power obtained in the second step and the optimum power found in the first step. The processor 11 measures the fluctuation of the rear end STj of the read signal corresponding to each of the subpatterns. The control means 12 determines the power of the rear end Pw2 for which the fluctuation of the forward end shows a minimum value and supplies this value as a control signal to the processing means 13. For specific record carriers, the rear part is optimized in the second step and the front in the first step. In the fourth step of the test phase, the device once again optimizes the writing power using the front and rear powers obtained in the second and third steps. The device writes a fourth test pattern using a series of pulses with write power in the middle part of the series of pulses that have different values for the subpatterns in the fourth test pattern. The writing powers are in a relatively small range around the optimal writing power obtained in the first step. The processor 11 and the control means 12 form a control signal representing the optimal write power Pw and supply it to the main processor means 13. Then, the information of the test phase represented by the signal Su can be recorded on the record carrier under the optimal registration conditions. The series of pulses formed by the processing means 16 which depend on the information signal Su are modified according to the control signals Sc. In the previous mode of the device, the power of the front of the pulse series of 3T and 4T is set to the power Pw? of the front end and the power of the rear of the series of impulses nT with n > 4 fixed to the Pw2 power of the rear end. The power of the middle part of the series of pulses is set at the optimum power Pw. In an alternative embodiment of the method according to the invention, PW? of the 3T and 4T pulse series is optimized to the same value in a first step. P2 of the impulse series of nT with n > 4 is optimized to the same value in a subsequent step. Pw2 of the 4T pulse series is optimized again in a next step. Figure 5 shows the SD output signals for a 3T, 4T and 6T mark that results from the alternative embodiments of the registration method according to the invention. An nT mark is written by a series of pulses (N-l). In the embodiment of Figure 5A, the first parameter is the width Ti of the first pulse of the series of pulses of 3T and 4T, the value of which is determined in a single optimization step. The width T2 of the pulses between the first and last pulse of each series of pulses has a predetermined value, for example 2/3 T. The time duration between the pulses in a series also has a predetermined duration, for example 1/3 T The width T3 of the last pulse of the series of pulses of nT with n > 4 determined in a single step of optimization. The width T'i of the first pulse of the series of pulses of nT with n > 5 has a predetermined value, for example, 1/3 T. In a subsequent optimization step, the value of T3 of the series of 4T pulses can be further optimized. Figure 5B shows an SD output signal of a series of pulses of 3T, 4T and 6T, of which the time duration between the pulses has been optimized. In the example shown, the pulse widths have a constant predetermined value, for example, 1/3 T, 2/3 T, 2/3 T, 2/3 T, 1/2 T for the pulse series of 6T. In a first optimization step, the duration T5 between the first and second pulses of the series of pulses of 3T and 4T is optimized. The duration Te among other impulses different to the first and last impulses of a series has a predetermined value, for example, 1/3 T. Similarly, the duration T'5 between the first and second impulses of the series of impulses with n > 5 has a predetermined value, for example 1/3 T. In a subsequent optimization step, the duration T7 is determined between a different one from the last, and the last pulse of the series of pulses of nT with n > 4. It is clear that combinations of the methods shown in Figures 3, 5A and 5B can be made for specific applications, for example, a power optimization of the front part and an optimization of the impulse width of the rear part. A recording device can record the optimal registration conditions obtained in the above procedure on the record carrier, together with an identification of the device. The registration conditions may include the writing powers P, P? and Pw2. the writing speed and the wavelength. The device is then able to verify whether it should be tested or not, a record carrier before registration. If the identification on the record carrier is equal to the identification of the device, the registration test procedure does not need to be performed and the reading of registration conditions of the record carrier can be used instead. Alternatively or additionally, a registration device or registry manufacturer may write values or start intervals for the parameters on the record carrier. The registration methods according to the invention are suitable for writing to erased record layers and for writing to record layers not yet erased, that is, for direct overwriting.

Claims (15)

CHAPTER CLAIMEDICATORÍO Having described the invention, it is considered as a novelty and, therefore, the content is claimed in the following CLAIMS:

1. The device for recording information on an optical record carrier, characterized in that it comprises recording means for writing a pattern of optically readable marks on the record carrier by irradiating the record carrier with a series of radiation pulses, a mark being formed by a pulse series, a generator of a test signal for generating a test signal comprising a test pattern and supplying the test signal to an input of the recording means, reading means for reading the marks on the record carrier and supplying a read signal, a jitter detector for measuring the fluctuation of the read signal corresponding to the test pattern and supplying an end jitter signal front edge and a signal for fluctuation of the trailing edge end, control means for supplying a first control signal and a second control signal which depends on the signal of fluctuation of the leading and trailing ends, respectively, the values of the signals of control correspond to an optimum quality of the read signal, processing means for converting the input information to be recorded in an output signal supplied to the recording means, the output signal corresponds to the series of radiation pulses and represents the information of input, each series of pulses has a front part and a rear part, an optimum value of the first parameter related to the front part being determined by the first control signal and / or an optimum value of a second parameter related to the rear part , being determined by the second control signal.

The device according to claim 1, characterized in that the first or second parameter is a radiation power of the front or rear part.

3. The device according to claim 1, characterized in that the first or second parameter is a width of a pulse of the front or rear.

4. The device according to claim 1, characterized in that the first or second parameter has a duration of time between two pulses of the front and rear.

The device according to claim 1, characterized in that the control means is arranged to excite or derive the value of the second control signal from a registered test pattern with an optimum value of the first parameter.

The device according to claim 1, characterized in that the control means are arranged to supply a third control signal depending on an amplitude of the read signal corresponding to the test pattern and to control the radiation power of the series of pulses, the value of the third control signal corresponds to an optimum quality of the read signal, and the processing means are arranged to receive the third control signal and use its value in the conversion of the input information to be recorded in »The exit sign.

7. A method for recording information about a record carrier, characterized in that it comprises the steps of: writing a trademark test pattern of the record carrier, read the test pattern and form a read signal, measure the fluctuation of the front end and the fluctuation of the rear end of the read signal, - determine the optimal values of a first and second control signal depending on the fluctuation of the front and rear end , respectively, converting the user information to be recorded in an output signal and supplied to the output signal of the recording means, the output signal corresponds to the series of radiation pulses and represents the input information, each series of pulses has a front part and a rear part, an optimum value and a first parameter related to the front part being determined by the first control signal and / or the optimum value of the second parameter related to the rear part, being determined by the second control signal.

The method according to claim 7, characterized in that it comprises the steps of - measuring an amplitude of the read signal, determining an optimum value of a third control signal depending on the amplitude, - controlling a radiation power of the series of pulses depending on the value of the third control signal.

9. The method according to claim 1, characterized in that the optimization of the first parameter using a first test pattern is the optimization of the second parameter after using a second test pattern.

The method according to claim 8 and 9, characterized in that the optimization of the radiation power is followed by the optimization of the first and second parameters.

11. A method for recording information on a record carrier in the form of marks of different lengths, a mark is formed by irradiating the record carrier with a series of radiation pulses, each series of pulses having a front part, a middle part and a back, each series of pulses belongs to a set of series of pulses that have different lengths, the set of series of pulses comprise a subset of series of short pulses and a subset of series of long pulses, characterized because the series of impulse of only one of the subsets has a front part and a middle part, which differ in a first parameter, and because the series of pulses of the other of the sub-assemblies has a middle part and a back part, which differ in a second parameter .

12. The method according to claim 11, characterized in that the subset of short pulses has a different front part and a middle part and the subset of the long pulse series has a different middle part and a rear part.

13. A method for recording information about a record carrier in the form of marks of different lengths, a mark is formed by irradiating the record carrier with a series of pulse radiation, each series of pulses having a front part and a back part, Each series of pulses belongs to a set of series of pulses having different lengths, the set of series of pulses comprises a first subset of series of short pulses and a second subset of series of long pulses, characterized in that the series of pulses of the first subset has a first value of a first parameter in the front and the pulse series of the second subset has a second value different from the first parameter in the front, and because the pulse series of the first subset have a first value in a second parameter on the back side and the pulse series of a second subset have a second differential value e from the back.

14. The method according to claim 11 or 13, characterized in that the first parameter is a radiation power, a pulse width in the series of pulses, or the time duration between two pulses in the series of pulses. The method according to claim 11 or 13, characterized in that the second parameter is a radiation power, a pulse width in the series of pulses or a time duration between the two pulses of the series of pulses.