MXPA00002686A - Device for reading or writing on optical recording media with disk type recognition means - Google Patents

Abstract

A device for reading or writing on optical recording media (4) with disk type recognition means has an optical scanning means (5) and a focus regulating circuit (5, 28). The object of the invention is to provide a device of this type which can reliably recognise in a short time the type (Tn) of the recording medium (4) inserted into the device. Another object of the invention is to provide a corresponding process. These objects are attained in that the disk type recognition means comprise a mirror signal generator (13), a threshold value generator (12, 14), a counter (15) and an evaluation unit (16). The disclosed process is based on the utilisation of a mirror-signal (MIRD) value of the device for disk type recognition.

Description

APPARATUS TO READ FROM AN OPTICAL RECORDING MEDIA, OR TO WRITE IN THE SAME, THAT IT HAS A MEANS OF IDENTIFYING THE TYPE OF DISC The present invention relates to an apparatus for reading from an optical recording medium, and / or for writing thereon having a disc type identification means for identifying the type of recording medium, and also to a corresponding method . An apparatus of this type is described in US-A-5, 414, 684. In the case of this known apparatus, in order to identify the type of recording medium, an attempt is first made to read the list of contents thereof, the so-called TOC or Table of Contents. If it is not possible to read the TOC, then one or a number of renewed attempts are made to read the information in one, or a number of other, locations in the recording medium. The type of optical recording medium is inferred from the success or lack of success of these attempts. What is disadvantageous about the known apparatus is that a complete adjustment operation has to be performed for each attempt to read the information. This operation includes, inter alia, the closing of the focus regulation circuit, the tracking regulation circuit, the driving regulation circuit and the like. This procedure is relatively complicated and time-consuming. An object of the invention is to provide an apparatus having a disk type identification means that is capable of reliably identifying the type of recording medium inserted in the apparatus in a short space of time. A further object of the invention is to specify a corresponding method. In accordance with the invention, these objects are achieved by means of the features specified in the independent claims. Advantageous developments thereof are specified in the dependent claims. According to the invention, the disk type identification means has a mirror signal detector, a threshold value generator, a counter and an evaluation unit. This has the advantage that a rapid identification of the type of recording medium is achieved. The disc type identification means has elements with a relatively simple function that allows information about the type of the disc to be obtained even when the recording medium can not yet be read, even if the focus regulation circuit is closed. The mirror signal is a signal that assumes different values if the scanning medium is scanning an information track or a version between two information tracks. In this case, the region located between two information tracks may be free of information, but may also carry in itself information, for example, control information or information of a class corresponding to that of the information tracks. According to the invention, an input of the mirror signal detector is connected to an output of the scanning means and an additional input is connected to the threshold value generator, and the counter is connected to an output of the mirror signal detector. and to an entrance of the evaluation unit. In the case of this advantageous combination of the individual elements, the threshold value generator specifies a threshold value for the formation of the mirror signal.

The counter counts the occurrence of the specific states of the mirror signal, for example, the number of high or low states, which corresponds to • transitions, zero crosses or similar. The evaluation unit evaluates the meter reading for the purpose of determining the type of recording medium. An advantageous development of the invention provides the apparatus having a means of identification of the thickness of the layer. This has the advantage that the means of identifying the thickness of the layer provides an additional criterion by means of which specific adjustments of the apparatus are appropriately pre-selected in order to further accelerate the identification of the disk type. In addition, or as an alternative, the additional criteria also serve as a criterion for the identification of the disk type, • thereby accelerating the identification and increasing its reliability. The layer thickness identification means serves to determine the thickness of a protective layer that is superimposed on a layer having information on the recording medium. A further variant of the invention provides an apparatus having a spacing identification means for determining the spacing of different layers of the recording medium from each other. This additional criterion also contributes to the acceleration and / or increase in the reliability of the disc type identification. In this case, the several layers are advantageously two or more layers of information. However, it is also likely within the scope of the invention that the layers are other layers that are present in the structure of the optical recording medium and can be detected. The method of the invention for identifying the type of an optical recording medium has the following method steps: aa) focusing on an information layer of the recording medium; bb) adjustment of a threshold value for the generation of a mirror signal; ce) counting the transitions of the mirror signal; dd) determination of the type of recording medium using the count. This has the advantage that a tracking mode and signal identification, which is to say reading the information stored in the recording medium, are not necessary, which allows it to quickly identify the type of disc. As soon as the type of recording medium has been identified, the device settings that are adapted to this type of recording medium, in particular for focusing, tracking and other regulation circuits, are selected. As a result, the start-up phase, that is, the time from the insertion of the recording medium into the apparatus or from the issuance of a start command to the start of playback or recording, can be kept short. As a result, the waiting time for the user is advantageously shortened. According to the invention, step dd), the recording means is determined as being associated with the nth type if the count is in an nth range of values, where n is an integer number. This has the advantage that, if appropriate, a multiplicity of different types of recording media can be identified without the counts that necessarily have to be accurate. In the simplest case, a check is made to see if the count is greater or less than a limit value. This limit value is considered as the limit between the two ranges of values. In the extreme case, an individual type of recording medium is identified, for example by virtue of the fact that the count is greater than a limit value. For n = 2, by way of example, the recording medium is determined as being associated with a first type if the count is between zero and a first value ml, while it is determined as being associated with a second type if the counting is between a second m.2 value and a third m.3 value. In this case, it is perfectly possible that the start value mO is also a value different from zero, or for the first value ml and the second value m2 are identical. The same applies, correspondingly, to three or a greater number of disk types that are identified. An advantageous development of the method provides a scanning beam of the scanning medium of the apparatus, which moves through a region of the recording medium that is larger than a region corresponding to the maximum eccentricity that is presented. This has the advantage that a faster and more reliable identification is possible due to the large number, achieved as a consequence, of information tracks crossed by the scanning beam. In this case, the eccentricity includes both the eccentricity dictated by the production of the recording medium; that is, the circular or spiral information tracks thereof which do not exactly center with respect to the axis of rotational symmetry, and the eccentricity generated by the operation, for example due to inaccurate centering of the recording medium in the apparatus . The eccentricity is subjected to tolerance intervals which, in practice, are generally not exceeded and which serve in the present as a lower limit for the induced movement of the scanning beam. An advantageous refinement of the invention provides for steps bb) to c and c) that a different threshold value that is adjusted in each case in step bb) is to be performed a number of times. This has the advantage that a large number of different disk types can be identified relatively quickly. A further advantage is that, in combination with a plurality of ranges of values, a small number of passes is sufficient to distinguish a large number of different types. Additionally, the counter verification by means of different passes makes it possible to increase in a relatively fast way the reliability of the verification. The invention further provides, after the type of recording medium has been determined, a check to be made to see if it is possible to focus on an additional information layer. This has the advantage that it is already carried out in the presence of a multilayer recording medium with the settings of the apparatus that is adapted to the recording medium, which reduces the time that elapses until the complete identification of the disc type is completed. , and also allows the multilayer recording medium to be identified. According to a further refinement of the invention, the method according to the invention is used first of all to identify the type of information layer in which the optical scanning unit effects the focus, then the settings of the apparatus are adapted to the The type of layer that has been determined, the information of the information layer is read and the type of recording medium of the information read is determined. This method has the advantage that the identification operation is shortened again, since it is not necessary to search for additional information layers if the presence and, if appropriate, the type of additional layers, can be identified from the information read from the first layer of information. information.

A variant of the invention provides the mirror signal detector the apparatus having at least one element that is variable as a function of frequency. This has the advantage that an element that is variable as a function of the frequency can be adaptively matched according to its properties to the track crossing frequency during the operation; with the result that the interference influences that occur in certain frequency ranges, in a selective manner of the frequency, are compensated or minimized. The mirror signal detector generates a mirror signal that indicates whether the scanning medium is scanning a data track or is located between two data tracks. For this purpose, the high frequency signal read from the disk is considered, in general. It has a high degree of moderation if the scanning medium is scanning a data track, while modulating only weakly if the scanning medium is scanning between two data tracks. This is the case at high crossover frequencies that the differences in modulation between the data track and the inter-space between the two data tracks are only very small. Slightly modulated input signals are presented, for example, in the case of high density recording media. In this case, when an information track is traversed, the intensity of the high frequency signal decreases, in some cases, only by 20% compared to the path of the reflective region that is between the information tracks, while this value is approximately 65% in the case of conventional compact discs. The apparatus advantageously has a control device which has an influence on the threshold value formation unit and also a tracking regulator. This has the advantage that in order to determine the type of optical recording medium, the tracking regulator is inactivated and the formation unit of the threshold value is adjusted to a fixed threshold value. The effect of the disconnection of the tracking regulator is that the information tracks of the recording medium are traversed. Depending on the type of the recording medium, it is possible to set a mirror signal with respect to a properly set threshold value or this is not possible, and from this a conclusion is drawn with respect to the type of optical recording medium. Likewise, the average is performed as a function of the frequency of the mirror signal. This has the advantage that in the case of a higher frequency signal, the average value is also formed at a higher frequency in order to be matched as quickly as possible to a possibly altered signal strength, as presented, for example, in the case of recording medium having a high storage density, as specified above. Additionally, provision is made for a higher and a lower threshold value to be used instead of a single threshold value, the mirror signal that is adjusted to a first value, for example, the value 1, when the value of The upper threshold is exceeded, and it is adjusted to a second value, for example the value 0 when the lower threshold value falls short, its value that is maintained otherwise. This has the advantage that the value of the mirror signal does not fluctuate to an unnecessarily large degree in the transition region between the two values, that is, it becomes smoothed. The hysteresis asks that the value of the mirror signal jump back and forth in the transition region between the two values. As a result, the frequency determination of the mirror signal also becomes even more accurate and the quality of the method according to the invention is increased. An advantageous variant of the method according to the invention consists in specifying a certain threshold value and in verifying whether or not a mirror signal can be established with respect to it. This has the advantage that the type of recording medium can be determined by means of a mirror signal detector that is present in any case, that is, without any additional dispensing. If a mirror signal can be established, then a first type of recording medium is being scanned; if, on the other hand, a mirror signal can not be established, then a second type of recording medium is comprised. The different types of recording medium differ, for example, in terms of their arrangement of tracks, the size of the width of the tracks or the spacing of the tracks, as is the case, for example, with conventional CDs and recording media which have a high density of storage, such as DVDs. Advantageously, a plurality of different threshold values are tested one after the other. This has the advantage of increasing the number of different types of recording media that can be identified. In • Consequence, types that vary only slightly 5 based on their properties can also be distinguished using the mirror signal that can be determined with respect to different threshold values. For example, the means of optical recording, of a writing, of many writings or not writable, differ, in some cases, only • slightly with respect to the threshold value that is adequate to form the mirror signal, they can still be reliably identified by the method according to the invention based on the plurality of threshold values used. The invention is suitable for distinguishing different types of recording medium from each other, such as inter alia, CD, CD-R, CD-RW and DVD, DVD-RAM and others. According to the invention, it is crossed the information tracks of the recording medium during the implementation of the method steps, this being done in the simplest case when disconnecting a track controller and using the eccentricity of the recording medium in its assembly on the device. It is particularly advantageous to actively implement the path of the information tracks. This has the advantage that the conditions to generate a mirror signal • they are always satisfied and as a result, an absent mirror signal can be assigned inambiguously to the type of recording medium. Additional advantages of the invention are apparent from the following description of the advantageous exemplary embodiments. HE understands that the invention is not restricted to the example modalities described. In the figures: Figure 1 shows a schematic illustration of an apparatus according to the invention, Figure 2 shows a schematic illustration in the exemplary embodiment of an apparatus according to the invention, • Figure 3 shows a diagram of typical signals that they are presented in an apparatus according to the invention, Figure 4 shows a block diagram and an apparatus according to the invention, Figure 5 shows a flow chart of a method according to the invention, lß Figure 6 shows a flow diagram of a variant of the method, Figure 7 shows a flow diagram of a further variant of the method.

Figure 1 shows a schematic illustration of the disc type identification means of an apparatus according to the invention. A high frequency data signal HF, is transferred by the scanning means 5 (not shown here), is fed to a threshold formation unit 12, 14 and a mirror signal formation unit 13. The threshold value formation unit 12, 14 generates a threshold value TH which is fed to a mirror signal formation unit 13. In an advantageous variant, a plurality of threshold values are formed, which in this case are specified as a higher threshold value UTH and a lower threshold value LTH. The mirror signal MIR generated by the mirror signal formation unit 13 is fed to a counter, which is also referred to as the frequency counter 15 in the subsequent text. The functions of the threshold value formation unit 12, 14 and the mirror signal formation unit 13 are explained in more detail below. The frequency counter 15 counts the edges (positive in the example mode) of the mirror signal MIR and, after a period of time which is determined by the externally preset clock signal, follows the count Z to a logic block 16 , which serves as an evaluation unit. A control unit 26 can both receive information from the logic block 16 and transfer the information to the logic block. A memory M is connected to the unit 14 for forming threshold values. In order to determine the type of recording medium, the control unit 26 specific to the threshold value formation unit 14 a threshold value TH to be adjusted. In general, the latter does not correspond to the threshold value adapted for the currently inserted recording medium. The consequence of this is that the MIR mirror signal that is generated in response is well done to a greater or lesser degree, this is manifested for example in the number of countable edges. The count or Z count then assumes a higher or lower value. In the simplest example mode, the Z count is compared to a comparison value ml in the logical block 16. If the count is below the ml value, then the presence of a first type of the recording medium, for example , a CD, is indicated by means of an output signal TI, while the presence of a second type, for example a DVD, is indicated otherwise. After the type of Tn of the recording medium has been determined, the specification of the threshold value TH is canceled and The latter is then adapted, as further described later, for normal operation. The refinements of the invention provide the control unit 26 for successively specify different specifications for the threshold value TH to the unit 14 of formation of threshold values, to evaluate the corresponding output signals of the logic block 16, to then determine a type Tn disk of a multiplicity of disk types and to transfer a corresponding output signal Tn. The memory M serves to store the specification values, interim results, results or other parameters. The logical block 16 also can perform, as described later, additional functions. Figure 2 shows a schematic illustration of a mirror signal detector 1 and an apparatus according to the invention. An envelope signal E is applied to its input and the mirror signal MIR is present at its output. The wrapper signal E is generated from a digitized high frequency DHF by means of a wrapper detector 2. In the exemplary embodiment, a maximum or peak value detector with a sustained value of slow formation is used for this purpose , as indicated in the block illustration of the envelope detector 2. The high frequency DHF is generated by means of an analog-to-digital converter 3, to which input a high-frequency data signal, HF, is applied. Figure 4 shows a schematic block diagram of a device according to the invention. An optical recording medium 4, which has schematically indicated concentric or spirally arranged information tracks 25, is scanned by means of a light beam 6 generated by a scanning means 5. The light beam 6 in this case is reflected from the optical recording medium 4 and passes to the detection means of the scanning medium 5, where it is converted into an HF data signal and into error signals, specified as the track error signal TE and the error signal of • FE focus in the present, by way of example, and 5 are transferred by the scanning means 5. The HF data signal is converted into a digitized high-frequency signal of DHF by means of the analog-to-digital converter 3, signal which is fed by detecting 1 of the mirror signal, by a part, and to the demodulation stage 7 (only • suggested in the present), on the other hand. The demodulation stage 7 serves to demodulate the data signal, which is modulated to record on the recording medium 4, and to transfer it as an audio signal u demodulated data signal. The envelope detector 2 described with respect to Figure 1 is not illustrated separately in Figure 4; it is part of the mirror signal detector 1, by way of example. The track error signal TE and the signal Focus error signal FE is also digitized by means of a 3 'analog-to-digital converter, the digitized track error signal DTE is converted to a DTE signal' in a conditioning stage 8 and transmitted to a stage 9 of signal processing. The latter also receives the MIR mirror signal transferred by the mirror signal detector 1, the two signals are logically combined and a signal is transferred to a tracking regulator 10. The latter transfers a driving signal to the scanning means 5, so as to move the latter in the radial direction with respect to the optical recording medium 4. In the case of a normal reading of the recording medium 4, the radial movement serves to follow the light beam 6 in an information track 25 of the optical recording medium 4, while in the case of a search operation, the movement The radius of the scanning means 5 serves for the travel of a pre-determined number of information tracks 25. The number of tracks traversed or traversed can be determined in this case, for example, when counting the positive edges of the MIR mirror signal. The result is used to move the scanning means 5 in a correspondingly radial manner, so that the searched track is reached as accurately as possible. The digitized focus error signal DFE is fed to a focus adjustment unit 28, which transfers a signal to drive the optical elements of the scanning unit 5 to the latter. This is done in such a way that the light beam 6 is focused on the information layer of the recording medium 4. According to a variant of the invention, the focus adjustment unit 28 has an additional function, in a state of special operation, to move the focal point of the light beam 6 in the axial direction of the recording medium 4, and to evaluate the values of the focus error signal FE is presented in the process. The thickness of the layer of the protective layer covering the information layer is determined from the presence of relative spaced yarns and maximum values in the focus error signal FE. If the recording medium is a multilayer recording medium, the presence and the respective spacing of a plurality of layers together are also determined. The focus adjustment unit 28 in this manner serves as a means of identifying the layer thickness or as a means of identifying the spacing. The control unit 26, which serves to establish the type of the optical recording medium 4, for example CD or DVD, is illustrated schematically as a dependent block in this figure. An output of the control unit 26 is connected to a mirror signal detector 1 in order to set a specific threshold value TH, as described further below. An additional output of the control unit 26 is connected to the tracking regulator 10 or tracks, in order to disconnect this regulator or, according to another variant of the invention, in order to control this regulator in such a way that they are traversed by Actively activates the information tracks 25. An output of the mirror signal detector 1 is connected to an input of the control unit 26. The type of recording medium that is currently scanned is established from the signal reported in this case , if appropriate from a plurality of communicated signals buffered in a memory M. The individual component parts of the mirror signal detector 1 will now be explained in more detail with reference to Figure 2. The envelope signal E a digital low pass filter 11 is fed, the cutoff frequency EFl of which is variable and is adjusted according to a control signal SL1. In the case of the IIR filter illustrated here, this is implemented since in the system clock signal CLK is divided by a value specified by the control signal SL1 and the frequency that has been reduced in this way produces the clock of filter operation 11 low pass, digital. The smaller the operation clock of the filter 11 is low, the lower is also the cutoff frequency EFl thereof. The output signal FIL of the filter 11 is fed to a mirror signal formation unit 13 designated as a comparator, by way of example. According to a first configuration, the mirror signal formation unit 13 in this case compares the signal FIL at a threshold value TH. If the value of the FIL signal is above the threshold value TH, then the value of the mirror signal in MIR is adjusted to a first value, in this case to 1; if, on the other hand, the value of the signal FIL is below the threshold value TH, then the mirror signal MIR is adjusted to a second value, in this case to the value 0. According to a second variant, the unit 13 of mirror signal formation compares the signal FIL with a higher threshold value UTH and a lower threshold value LTH. In this case, the value of the mirror signal MIR is set 1 if the value of the signal FIL is above the clock of the upper threshold value UTH, and is set to 0 if the value of the signal FIL, is below of the lower threshold value LTH. The value of the mirror signal MIR remains unchanged as long as the value of the signal FIL is between the upper threshold value UTH and the lower threshold value LTH. A variant consists in maintaining the threshold value TH or the upper threshold value UTH and the lower threshold value LTH constant, or not changing them as a function of the frequency. However, it is advantageous to adapt the threshold values TH or UTH and LTH as a function of the frequency. A second low pass filter 12, digital for this purpose, is provided, which filter is also designed as an IIR filter. As described with respect to the filter 11, the cutoff frequency EF2 of the filter 12 is varied as a function of the frequency by reducing the clock signal of the CLK system by a factor specified by a control signal SL2 to form the operating clock of the filter 12. From the input signal the filter 12, the FIL signal, a free average value of the deviations of higher frequency is formed, by virtue of a suitably selected filter characteristic, and transferred as the threshold value TH. The filter 12 thus acts as a weighting unit. The threshold value TH is fed directly to the mirror signal formation unit 13 according to the first variant described above, this being illustrated by a line discontinued in Figure 2. It is advantageous, however, to feed the value threshold TH to a threshold value formation unit 14, which forms the upper threshold value UTH and the lower threshold value LTH from the threshold value TH by means of a higher hysteresis UHY value and a hysteresis value lower LHY, for example by addition or subtraction. The mirror signal MIR is transferred and fed to a frequency counter 15 within the mirror signal detector 1. This frequency counter operates with a fixed clock signal CL1, which can be adapted in a device-specific manner but is constant during operation. In the exemplary embodiment, the frequency counter 15 is designed as an 8-bit counter whose overflow forms the output signal. If the output signal of the frequency counter 15 is to have a higher frequency, then the provision is made to transfer the value of the highest bit or the second highest counter bit.

Any other bit is also suitable for this purpose, depending on the desired frequency. The output signal of the frequency counter 15 forms the input signal of a logic block 16, which adjusts the control signals SL1 and SL2 according to its input signal using specified threshold values, according to a specified algorithm, or using a stored table. The example embodiment described allows a correct mirror signal MIR to be obtained even when using an optical recording medium 4 having a high storage density, such as a DVD, for example, and in the case of high crossover frequencies of clues. In this case, the envelope signal E is compared with a threshold value TH in order to generate the mirror signal MIR. Since the envelope signal E is modulated only by approximately 20% with respect to the maximum value during the crossing of the tracks, in the case of the recording medium 4 having a high storage density, while this amount is approximately 65% in the case of conventional recording means, such as in the case of a CD, frequency-dependent, frequency-dependent filters 11, 12 are provided according to the invention. The frequency dependence in this case starts with a low cutoff frequency EFl, EF2 at the start of a track crossing operation in order to suppress the high frequency interference influences, which are, for example in the frequency range of the frequency of crossover tracks at maximum crossover speed. As the track crossing speed increases, that is, as the frequency of the mirror signal MIR increases, the cutoff frequency EFl and / or EF2 increases to allow the frequencies that are necessary to pass. Towards the end of the track crossing operation, the cutoff frequency EFl, EF2 are gradually decreased. In order to take into account the relatively narrow modulation bandwidth of the envelope signal E, which is of the order of magnitude of only 20%, as described, the second low pass filter 12 is provided for the purpose of forming the value threshold TH, a filter that reacts rapidly to changes in the amplitude of the HF data signal and thus of the envelope signal E, which can be caused, for example, by the eccentricity of the recording medium 4, by changes in the capacity of reflection, or by other interference influences. The low pass filter 12 can also be adapted as a function of frequency. The adaptation dependent on the frequency B of the filters 11, 12 depends on the crossover frequency of the tracks, which is why a measurement of this frequency is obtained from the period of the mirror signal MIR. The envelope signal E is generated by means of the envelope detector 2 by detection of the peak value and drops slowly, as indicated in a symbolic way. • Figure 3 illustrates the typical profile of a number of signals that are presented in the device according to the invention against time t. The output signal FIL that corresponds to the signal of filtered envelope E is free from high frequency interference overlays. The signal of the threshold value TH that is obtained when filtering by low pass is derived from the signal? FIL. It modulates to a lesser degree than the FIL signal and has steps by way of internal filter clock 12. The mirror signal MIR, which is illustrated as the mirror signal MIR in FIG. 3, is formed in the mirror signal formation unit 13 by comparison of FIL and TH signals . The MIR is a value "high" or one when the signal FIL is below the threshold value TH, while the inverted mirror signal MIR is "low" or the value 0 when the signal FIL is above the threshold value TH. The arrow 21 indicates the duration of the period of the mirror signal MIR, this period duration that produces the frequency of the crossing of tracks that is used, in turn, for the adaptation of the filters 11 and 12. The method, used in the exemplary embodiment, for the frequency-dependent formation of the mirror signal MIR of parameters is described with reference to Figure 2. In a first step of method a), the envelope signal E is formed from the HF data signal by means of the envelope detector 2. It is subsequently filtered, in step b), by means of the filter 11 which takes into account a cutting frequency EFl. The filtering envelope signal FIL is then compared, in step c), with a threshold value TH by means of the mirror signal formation unit 13. The parameter mirror signal MIR is set, in step d), to a first value if the filtered envelope signal FIL is above the threshold value TH, and to a second value if it is below the threshold value TH. In step e), the frequency of the mirror signal MIR is determined by means of the frequency counter 15. The value of the cutoff frequency EFl, EF2 is changed as a function of the frequency of the mirror signal MIR in the step f). While the operation of the crossing of tracks has not yet been completed, the derivation to a first step takes place in step g), otherwise the method is terminated. The threshold value TH is formed by averaging the envelope signal E by means of the filter 12. This weighting also takes place as a function in the frequency of the mirror signal MIR, in this case as the variation of the control signal corresponds SL2. A higher threshold value UTH and a lower threshold value LTH are formed from the threshold value TH by means of the unit 14 for forming threshold values. The parameter mirror MIR signal in this case is set to a first value if the filtered envelope signal FIL is above the upper threshold value UTH, and to a second value if it is below the lower threshold value of LTH, another mode the preceding value of the mirror signal MIR of parameter is maintained. Figure 5 depicts a flowchart of an exemplary embodiment of a method according to the invention for identifying the type of an optical recording medium. The principle behind this method is to use a parameter mirror MIR signal in a device to read from the optical recording medium 4 and / or write to it. For that purpose, step aa) is performed, first of all by focusing on the information layer of the recording medium 4. This is done by means of the focus adjustment unit 28 in a manner known to a person skilled in the art. . In the focused state, the value of the focus error signal is almost zero; the focus operation is therefore indicated by FE-0 in this case. In step bb), a threshold value TH to form the mirror signal MIR is specified. According to a variant, a provision is made to perform step bb in a repeated manner. In this case, a threshold value Thi is specified during the i-th pass. In the following text, the index i is specified even when performance by repeated performance is not included. The counter 15 forms a count Zi from the mirror signal MIR formed by means of the threshold value THi. This is specified in step ce). The type Tn of the recording medium 4 is determined from the account or the Zi accounts in step dd) or de), respectively. In step dd), a simple variant is specified according to which the nth type Tn is included if the count Zi is within a range of values joined by the values mn and mn + ?. In the step of), a more general specification is given by the presence of the n-type Tn can also be defined by the combination of a plurality of Zi accounts. According to a variant of the invention, after step c), in step cd) it is stored first of all the account Zi that has been determined, in step c) the count i is incremented, and in step c) the method is derived to step bb) as long as a maximum value imax is not exceeded. In this case, the threshold value THi is changed a number of times, the corresponding accounts Zi are stored and used during completion of the step of) to determine the type Tn. A modification provides, after step ce), first of all that a check is made to see if a type Tn can be determined unambiguously using the information already present, ie first of all so that the step of) is executed. Only, if it is not yet possible to determine the type, the method then branches to step cd), otherwise the process ends. A further variant provides in step df), for the identification of the layer thickness of the protective layer covering the information layer, or of the separation layers which, if appropriate, separate a plurality of recording medium layers 4. The thickness of the layer determined in the process serves as an additional information point, which, for safety and simplicity, is also designated as a Zi count, to determine the type Tn in the step of). Step df) is preferably coupled to the focusing operation of step aa). According to a further variant, after step aa) and before step bb), a periodic movement of the scanner 5 in the radial direction is initiated. This is specified in step ab). The periodic movement ends as soon as the type of recording medium has been established. Figure 6 depicts a flowchart of a further exemplary embodiment of a method according to the invention. In this case, steps aa) to that of) correspond to those described with respect to Figure 5, with the difference that in this case the Tin type of the information layer in which the focus is detected is determined. Once the Tin type is known, in step ee), the settings of the apparatus, in particular those for the track, focus and other regulation circuits, are adapted to the Tin type of the determined formation layer. In step ff) the information is read from the current information layer and the type Tn of the recording medium 4 is determined using the information read and, if appropriate, the Tin type already determined. In general, the type Tn can be collected from the information read, otherwise it is determined, for example by using a stored table or a suitable algorithm, from the information read. Figure 7 depicts a flowchart of an exemplary embodiment of a method according to the invention for identifying the type and an optical recording medium. The principle behind this method is to use a parameter mirror MIR signal in an apparatus for reading from the optical recording medium 4, and / or write in it. For this purpose, in step w), a threshold value THi is specified which, in step c) is compared to the output signal FIL derived from the HF data signal, from which the mirror signal is formed MIR in step d). In step e), a check is made to see if a mirror signal MIR can be formed with respect to the threshold value THi, which is to say whether the value of the mirror signal MIR remains constant or changes with a frequency Fi , which can vary very well. From this information, in the simplest case Fi = 0 Fi? O, the type of recording medium 4 is determined. In this case, the adjustment of the threshold value THi is initiated by the control unit 26, which drives the threshold formation unit 14 of the mirror signal detector 1 correspondingly, receives the frequency Fi from the latter, or, as described above, a Zi account and determine the type Tn. The following method steps are advantageously implemented in addition to the steps described above, but are not absolutely necessary for the method according to the invention. In step v), a value counter i is set to an imin start value. In the normal case, imin = l, and the account is required only when it is proposed to specify more than one threshold value TH. In step w), a threshold value TH is adjusted to a specified threshold value THi according to the count i. Steps a) and b), ie the formation of the envelope signal E from the HF data signal and the envelope signal filtering E taking into account a cutoff frequency EFl, which corresponds to the example mode finally described with anteriority. The filtered envelope signal FIL is compared to the threshold value TH i in step c), and in step d) the parameter MIR mirror signal is set to a first value, in this case the value 1, yes the signal Filtered envelope FIL is above the threshold value THi and a second value, in this case the value zero, if it is below the threshold value THi. The frequency Fi of the mirror signal MIR is determined in step e). The derivation to step a) takes place in step g) if a first specified time interval has not yet been exceeded. The time interval ti is selected such that steps a) to e) are iterated sufficiently to allow a significant frequency Fi to be established. The value of the frequency Fi is stored in the memory M in step 1) after the first time interval ti has been exceeded. This storage operation can be omitted if only a single threshold value THi is used in the method. The increment of the counter value i by a specified value, in general by the value 1, in step m) is also necessary only when a plurality of threshold values are used. In step n), the derivation of step w) is carried out as frequently as until count i has exceeded a specified final value imax. Subsequently, in step p) the type of recording medium 4 is determined from the set Fi frequencies, which are generally sufficient to distinguish between Fi = 0 and Fi? 0. The invention guarantees that a mirror signal MIR can always be generated by ensuring that the information tracks 25 of the recording medium 4 are traversed at the same time as the implementation of the steps of the method. For this purpose, the regulation mode of the normal tracking controller 10 is inactivated before the implementation of the first step of method v) and reactivated at the end of the last step p). During the implementation of method steps v) ap), the scanning means 5 is operated in such a way that the information tracks 25 are traversed, for example by the use of an appropriate mode of operation of the tracking controller 10. For this purpose, the scanning means 5 is preferentially deviated periodically, alternately in the positive and negative directions.

Claims (12)

1. CLAIMS 1. An apparatus for reading from an optical recording medium and / or writing thereon, having a disc type identification means, having an optical scanning means and a focusing regulation circuit, wherein the medium for identification of the disk type has a mirror signal forming unit, a counter and an evaluation unit, characterized in that the disk type identification means additionally has a threshold value forming unit to form one of a plurality of possible threshold values.
2. 2. The apparatus according to claim 1, characterized in that the inputs of the mirror signal formation unit are connected to an output of the scanning means and the threshold value formation unit, and in that the counter is connected to an output of the mirror signal formation unit and to an input of the evaluation unit.
3. 3. The apparatus according to claim 1 or 2, characterized in that the apparatus has a means of identifying the layer thickness to determine the protective layer covering a layer of information of the recording medium, or a means of identification spaced to determine the spacing between both • layers of information.
4. 4. The method for identifying the type of an optical recording medium, having the following steps of the method: 10 aa) focusing on a layer of information of the recording medium, bb) adjusting one of a plurality of possible threshold values for generation of a mirror signal, threshold value that is inappropriate 15 to generate the mirror signal for at least one type of recording medium, c) count the transitions of the mirror signal, dd) Determine the type of the medium • 20 recording using the account.
5. 5. The method according to claim 4, wherein the step dd) of the recording medium is determined as being associated with an nth type 25 if the count is in a nth range of values, where n is a whole number
6. 6. The method according to any of the • claims 4 and 5, characterized in that the scanning beam moves through a region of the recording medium that is greater than a region corresponding to the maximum eccentricity that is presented.
7. 7. The method according to one of claims 4 to 6, characterized in that the steps bb) to c and c) are performed a number of times, a different threshold value that is adjusted in each case in step bb).
8. 8. The method according to one of claims 4 to 7, characterized in that after the type has been determined, a check is made to see if it is possible to focus on the • 20 a layer of additional information.
9. 9. The method according to one of claims 4 to 7, characterized in that? the method first of all is used to identify 25 type of the information layer in which the focus is made, in which the settings of the apparatus are adapted to the type of layer that has been determined, in which the information is read from the information layer and the type of the recording medium it is determined from the information read.
10. 10. The method according to one of claims 4-9, wherein a check is made to see if a square wave signal can be formed from a data signal and a threshold value and the type of recording medium is determined from of this information, characterized in that the square wave signal is a mirror signal formed from an envelope signal of the data signal.
11. 11. A method for identifying the type of an optical recording medium by means of a parameter mirror signal in an apparatus for reading from and writing to the optical recording medium, comprising the following steps of the method: v) adjusting a counter value to a start value w) setting a threshold value to a specified threshold value a) forming an envelope signal from a data signal b) filtering the envelope signal • 5 taking into account a cutoff frequency c) comparison of the filtered envelope signal with the threshold value d) adjustment of the parameter mirror signal to a first value if the envelope signal 10 filtered is above the threshold value, and a second value if it is below the threshold value e) determination of the frequency of the mirror signal g) derivation to step a) if a first time interval is not exceeded specified 1) storage of the frequency value if the first time interval is exceeded m) increment of the value of the counter by a • 20 specified value n) branch to step w) if the value of the counter does not exceed a specified end value p) determination of the type of recording medium of the set frequencies
12. 12. The method according to one of claims 4 to 11, characterized in which the information tracks by means of recording are traversed simultaneously.