MXPA01002743A - Method of scanning a recording disc for defects, and recording device for recording information on a disc-shaped recording medium - Google Patents

Abstract

A method and a DVR video recorder (20) for recording real time video signals on a DVR disc (1) are described. The disc may exhibit two-dimensional spot defects (11;12;13) but the DVR error correction system is very powerful and is capable of correcting errors as a result of small spot defects (11;12). In order to examine in a rapid and efficient manner whether the disc has large spot defects (13), the integrity of predetermined test tracks (2T) is assessed on the basis of the tracking signal. When a defective test track (2T2;2T3) is found the proximity of said test track is examined further. If the number of affected tracks appears to be small, recording in these tracks is allowed;if the number of affected tracks appears to be large, these tracks are entered in a defect list, which is preferably recorded on the disc. During recording the tracks appearing in the defect list are skipped.

Description

Title: Scanning method to detect defects in a recording disc, and recording device to record information in a disc-shaped medium The present invention relates generally to a method for recording information in a disk-like recording medium of the type having a multitude of concentric circular recording tracks. Said recording tracks may take the form of individual circular tracks or continuous spiral tracks. Each track is divided into logical blocks and each block has a data area for recording data. In addition, each block usually has an area reserved for the recording of a reference number or a "reference account." In general, the amount of information that will be recorded in a recording session is greater than a block The information to be recorded, which is also known as "file", is divided into successive packets of data that are the size of a block, and the successive packets of data in a file are recorded in different disk blocks. For fast data transfer, it is recommended that successive packets of data be recorded in successive blocks. Thus, the recording process can proceed virtually continuously. In this way, during the subsequent reading (reproduction) of the information recorded on the disc, the reading process can proceed continuously. In practice, a disk may exhibit defects as a result of information that can not, or at least not reliably, be recorded where the defect is located. The causes of defects can be defects in the disc material or imperfections in the disc surface. Therefore, the blocks affected by the defect are no longer suitable for recording.

The defects can be of a very local nature and can be confined to a small portion of a single block, whose defects will be known in the following as "dot defects", but it is possible for a defect to occupy a larger portion of the surface area of the recording disc. The last mentioned defects will be known hereinafter as "stain defects". There are several possibilities to copy with the incidence of defects in the recording discs. A first possibility is to review, at regular intervals during the writing process, if the information to be recorded was recorded correctly. This is done by reading the recorded information and by comparing the information that is read with the source information: if it seems impossible to read the information or if the reading of the information deviates from the source information, a writing error is detected, which it is subsequently repaired by repeating the write operation in another recording area of the recording disc. An example of such a post-write reading method is described in US-A 5,218,590. It is even possible that the recording disc has certain spare recording areas, which are usually not described and are only used to rewrite information that was not written with the first write operation: an example of this is described in US-A 5,623,470. A disadvantage of such post-write read methods is that the recording process reduces the speed by verification during the recording process and possible rewriting of an information packet. Therefore, such soto methods are suitable if the speed of the recording process is not a critical factor, for example, when the information to be recorded is available in a memory and can simply be recovered again. This situation occurs for example when recording data from the memory of a computer.

However, there are situations in which the speed of the recording process, in particular the continuity of the recording process, is a critical factor. For example, such a situation occurs in the case of a real-time recording of signals that have a high index of information, like audio signals or in particular, video signals. In order to allow the recording process to be carried out without any problem it is recommended that preferably the information referring to the location of the defective blocks be available before starting the recording process. Thus, this information is used during the recording and simply the defective blocks are skipped. An example of this recording process is described in JP-A-09.102.173. The present invention relates more specifically to a method for acquiring the information to specify the location of the defects. Until now, it is traditional to acquire such information by recording test data on the recording disc during a test session, reading the recorded test data and then comparing said data with the source data. Thus, the traditional thing is to examine in this way all the blocks of all the tracks recorded on the recording disc. This has been clearly described in, for example, EP-A 0 798 716, from which the preamble of claim 1 is known. However, this method has the disadvantage that it takes a long time. This is a particular disadvantage in the case of a video recorder, since the user expects the video recorder to be ready to record just after the introduction of a new disc. A main objective of the invention is to provide a more efficient method to prove that there are no defects in a recording disc. The present invention proposes a method that is particularly useful in recording systems that include a very powerful error correction. For example, said recording system is the Digital Video Recording (DVR), whose system is known by itself and will not be described here in more detail. It is only necessary to take into account that in the DVR there is a recording layer arranged at a comparatively short distance (approximately 0.1 mm) from the surface of the disk. A laser beam for writing / reading is used which has an approach that is located very close to the surface of the disk and which is facing the origin of the laser, as a result of which the laser spot formed on this surface is comparatively small. Therefore, the system is susceptible in comparison to slight disturbances of the disk surface. The correction of errors of the DVR system is so powerful that the incidence of small errors in small portions of a block, in particular in those caused by point defects, no longer present problems. If the recording discs to be used for DVR have only point defects, these recording discs should not even be examined for the presence of such imperfections. However, the surface of the disc can also exhibit large continuous areas of two-dimensional defects, i.e., so-called blemish defects. The affected portion of the block will be as large as the blemish defects and the affected portion of a block can be so large that the error correction system can no longer, or at least not quickly enough, correct the writing errors resulting Therefore, it is advisable to know the locations of the blemish defects that are larger than the predetermined acceptance threshold.

Therefore, a specific objective of the present invention is to provide an efficient method for testing a disc-shaped recording method, in which defective areas whose physical dimensions are larger than the predetermined threshold size are quickly identified at the same time. time that defective areas whose physical dimensions are less than this threshold are ignored. The present invention advantageously uses the fact that a spot defect whose dimension in the longitudinal direction of the recording track (tangential dimension) is so large that the error correction system can not correct the resulting recording error and also has a large dimension in transverse direction of the recording tracks (radial dimension) that the spot defect extends over many adjacent recording tracks, and the present invention is based on recognition of the fact that it is not necessary to individually examine all recording tracks , but it is sufficient to examine only a few recording tracks, which are called test tracks, which are spaced at a long distance from each other. There is always an area with a large number of untested recording tracks located between the individual test tracks that have been examined. If no defects are found during said inspection process, it does not mean that the disc examined has no defect, but it is obvious that a possible defect will have a radial dimension smaller than said number of unexamined recording tracks located between two adjacent test tracks. , and that the tangential dimension of said blemish defect that is still present will also be small. The present invention also proposes to examine the direct proximity of the test track more closely if it is found that a test track exhibits a defect, in order to determine the size of the defect. This can be done before recording, but preferably after recording, and, during recording, a suspicious area is skipped on opposite sides of the test track that is defective.

Therefore, according to the present invention an acceptable compromise is reached between a short test time and the reliability of the test.

As it was said, before it was usual to check that there were no defects in the disk based on the writing and reading of the test data. One drawback of such test methods is that they consume a lot of time. Another disadvantage is that said methods can not be used for write-once recording discs. Another objective of the present invention is to overcome these problems as well. For this purpose, the present invention proposes to examine a recording track of a recording disc based on the signal of the track. For this purpose, a laser beam simply tracks the relevant track of the recording disc without there being written information on said track or without the information being read from said track. If the recording disc has a defect, the track signal will exhibit identifiable deviations or errors or even be completely lost. This can be detected in a very simple way. The defective criterion proposed by the present invention is that the absolute value of the track signal exceeds the predetermined threshold level by a predetermined time or more. A great advantage of this test method proposed by the present invention is that an unwritten operation is performed and that the test can be performed quickly. These and other aspects, features and advantages of the present invention will be illustrated by means of the following description of a preferred form of a test method according to the invention with reference to the diagrams, in which: Figure 1 is a view in schematic plan of a part of the disc-shaped recording medium; Figure 2 is a synoptic diagram illustrating a part of a recording apparatus in which the present invention is incorporated; Figure 3 is a diagram of operations of a test method according to the invention; and Figure 4 is a diagram of operations of another test method according to the invention. Figure 1 is a schematic plan view of a part of a disc-shaped recording medium 1, for example and in particular an optical recording disc for use in DVR. Disk 1 has a multitude of circular recording tracks previously defined. To illustrate the present invention, the recording disk 1 in Figure 1 is shown with three disk defects 11, 12 and 13 in the form of spots. The radial and tangential dimensions of each spot defect are of the same magnitude as the spot defects 11, 12 and 13 represented as circular spots in Figure 1. The radial and tangential dimensions of the first spot defect 11 are comparatively small. Consequently, the length of the affected track of a recording track 2 afflicted with the first spot defect 11 is comparatively small, the number of tracks affected by the first spot defect 11 is also comparatively small. The same applies to the second spot defect 12. The DVR system has a very powerful error correction system, so it is immune to errors produced in a comparatively small track length. Only when the affected track length becomes comparatively large, will the error correction system be able to correct the resulting recording errors. By way of illustration, this is the case with the comparatively large spot defect 13 and it is also apparent in Figure 1 that the number of recording tracks 2 affected by the comparatively large spot defect 13 is greater than the number of recorded tracks. affected by the comparatively small blemish defects 11 and 12. Conventionally, each recording track 2 is tested when writing and reading data, which takes a long time. In accordance with the present invention, it is proposed to examine only a limited number of recording tracks of disc 1, the tracks to be examined will be referred to hereinafter as "2T test tracks". Figure 1 shows some of these test tracks as strong lines referred to as 2T1, 2T2, etc. The successive 2T test tracks are spaced by a predetermined number N of recording tracks. In the following, it is assumed by means of the example that N is 50. However, for someone skilled in the art it will be evident that N can have any other value appropriately selected. Figure 2 schematically illustrates a recording apparatus 20 for recording information as video signals in real time on a recording disc 1, in which the recording apparatus 20 of the present invention is incorporated. The recording apparatus 20, which will also be called "video recorder", has a writing / reading unit 21 adapted to record information and to read it from the recording disc under the control of the control unit 22. As is possible Using a standard writing / reading unit for this purpose, this unit will not be described in more detail. It should be noted that the control unit 22 can give commands to the write / read unit 21 by means of a command line 23, for example, the command to carry out a write or read operation and the sequence number of the the relevant recording track 2 to which the write or read operation relates. As is well known, an optical recording system uses a laser beam to write information on a track of the rotating disc 1 and also to read information of the track on the recording disc 1. As is well known, the laser beam is controlled for follow the trail. For this purpose, a track signal is used that is based on the reflection of the laser beam from the track on the disk. If the beam is placed exactly in the center of the track, the track signal has a known nominal value; in the following description, for the sake of simplicity it will be assumed that the nominal value is zero, but for an expert in the matter the necessary adaptations will be evident if the nominal value is not zero. If the beam does not focus exactly on the track, the reflected beam will contain information to control a correction movement of the laser beam, as it is known per se. For the sake of simplicity, it will be assumed in the following description that the value of the track signal is proportional to the radial deviation of the laser beam from the center of the track and that the sign of the track signal indicates the direction of the track. the deviation. If the disk has surface defects, the track signal will deviate or be completely lost, which can be detected in the writing / reading unit 21 and / or in the control unit 22, as will be apparent to those skilled in the art. matter. The track signal is obtained even if the control unit 22 only instructs the writing / reading unit 21 to follow a track with no information to be read or written. The track signal of the addressed track is transferred to the control unit 22 by the write / read unit 21 by means of a signal line 24. In the field of the present invention, it is generally assumed that a track has a satisfactory integrity if there is no disturbance in the track signal over the full length (one full revolution) of a track, or if they appear at most on a small portion of the track; hereinafter referred to as "correct track" or "track OK". However, if the track signal contains one or more disturbances in a very large part of the track, it will be referred to below as "fault track". The lack of track integrity or track failure will be seen as an indication of the presence of a surface defect, which affects at least a portion of the relevant track. Thus, the track signal S indicates the presence of a defect in the surface without requiring a writing / reading / comparison cycle that takes a long time. The control unit 22 of the recording apparatus 20 is adapted to carry out a test procedure according to the present invention to determine which tracks should not be used for recording because they must be severely damaged, when the video recorder 20 receives a command of recording by the user, or even before this, when a disc 1 is loaded into the video recorder 20 for the first time. An example of this procedure is clarified with reference to Figures 1 and 3. The test begins at step 101 when a new recording disc 1 is loaded into the video recorder 20. In step 102 the control unit 22 instructs the unit of write / read 21 to determine the integrity of the first test track 2T1 to be examined. The sequence number or direction of this first test track 2T1 can be 1. The write / read unit 21 points the laser beam to the first test track 2T1 and tracks the track for one full revolution. It will be evident that in this case the presence or absence of data in said track is not relevant: any information that may be present is ignored. The test only aims to examine whether the writing / reading unit 21 can follow the 2T1 test track without any problem about the full length. Upon completion of a complete revolution of the disk 1, or during this revolution, the control unit 22 checks in step 103 whether the integrity of the test track examined is good based on the received track signal. If this is the case, as shown for the first test track 2T1 in Figure 1, the control unit 22 instructs the writing / reading unit 21, in a step 104, to move the laser beam by means of the tracks N, and control unit 22 proceeds to a step 105. N may have a predetermined fixed value, for example and preferably 50. In step 105, it is checked whether the end of the disk has been reached. If that is the case, the test procedure is stopped; if this is not the case, the control unit 22 returns to step 103 to test the integrity of the next test track. Thus, the recording tracks that lie between the successive test tracks are skipped, that is, they are not tested. If a blemish defect is located in the immediate area, such as the first blemish defect 11 shown in Figure 1, this will not be detected. If in step 103 it appears that track errors are encountered, the control unit 22 proceeds to step 110 to determine the radial dimension of the detected spot defect, which is expressed as the number of tracks 2 affected by this spot defect, which will be denoted here by the letter X (track), where the parameter "track" is the sequence number of the relevant recording track 2. This process is followed, for example after exploring the second test track 2T2 that It is shown in the Figure 1, where a track error will occur as a result of the second spot defect 12. The control unit 22 is adapted to subsequently determine in a step 120 the magnitude of the spot defect detected by comparing the radial dimension X (track) with a predetermined threshold value. If it is found, as with the second test track 2T2, that the radial dimension X (track) determined by the detected spot defect, such as the second spot defect 12, is smaller than the predetermined threshold M, it is decided that the tangential dimension of the detected spot defect is allowed. The affected track length of each recording track affected by the second spot defect 12, such as the second test track 2T2, is comparatively small, and the error correction system can handle and correct writing errors and / or resulting reading. Thus, although these recording tracks are affected by the blemish defect, they are usually released for recording purposes. The control unit 22 now returns to step 104. For example, a suitable value for M is approximately 50. If it is in step 120, as in the case of the third test track 2T3, that the radial dimension X (track) found by the detected spot defect, such as the third comparatively large spot defect 13, is not smaller than the predetermined threshold M, it is decided that the tangential dimension of the spot defect detected It has a long not allowed. The affected track length of each recording track affected by the third spot defect 13, such as the third test track 2T3, is so large that the error correction system can no longer correct writing and / or reading errors resulting The control unit 22 proceeds to step 130 in order to record the addresses of the tracks affected by the third spot defect 13 in a defect list stored in a memory 25 associated with the control unit 22. After this, the control unit 22 returns to step 104. The defect list may take the form of an initially empty memory in which only the sequence numbers or addresses of the affected tracks are stored. The defect list may alternately take the form of a memory having a predetermined number L of storage locations, each storage location corresponds to the sequence number of a given recording track and the content of said storage location indicates the relevant recording track affected or not affected. It is suitable if each storage location consists of a single bit. Now the recording apparatus 20 is ready to record information (video signals) on the disc 1. The writing process will be substantially identical to the standard writing process, provided that the control unit 22 is adapted to read the list of defects in the memory 25 during writing and to skip the recording tracks that appear in the list. It will be evident that it is also possible to record a very fast information stream, for example, a digital video signal in real time, continuously without having problems due to possible spot defects: in case of comparatively small spot defects, the error correction system to correct any error and in the case of comparatively large blemish defect, simply skip the affected tracks. Moreover, it will be apparent that the method for testing the recording tracks of the recording disc, as proposed in accordance with the present invention, requires a comparatively small amount of time. The test method proposed by the present invention for testing the recording tracks of the recording disc may be carried out each time a new disc 1 is loaded in the apparatus 20. However, it is possible for the control unit 22 to adapt to record the list of defects on the disk that was just tested. Then, the control unit 22 for first checking everything, each time a new disk 1 is loaded in the device 20, if a list of defects has already been recorded in that disk and, if this is the case, loading it in the memory 25. In step 104, the skip of tracks N to be skipped can be made with respect to the test track 2T2 as shown, but this skip can also be made with respect to the track having the highest sequence number, which has been tested in the process of step 110. In step 110, the parameter X (track) can be determined by testing all individual recording tracks having descendant sequence numbers in a step similar to step 103, starting from the relevant test track, until a recording track without track errors is found, and subsequently by testing all individual recording tracks that have ascending sequence numbers, starting again from the relevant test track, until it is Find a recording track without track errors. However, it will also be possible to skip a number of tracks each time or cut the jump between the two tracks to be tested in each case, starting from N. For those skilled in the art, it will be evident that several search strategies are possible. efficient However, for the sake of simplicity, these are not illustrated in the operation scheme of Figure 3. As already noted, the integrity of the track being examined is determined based on the track signal received in step 103. Although a variety of criteria are conceivable, the present invention proposes a criterion which, on the one hand, can only be implemented comparatively, and on the other, produces satisfactory reliability. By the criterion proposed by the present invention, it is assumed that, under normal conditions, the track signal as a rule does not deviate much from the nominal value corresponding to the center of the track that was examined and that any significant deviation will only have a short duration . Thus, according to the present invention, it is assumed that the examined track is defective when it is found that a track signal, indicative of a significant deviation with respect to the center of the track, has a duration of a not allowed length. The track signal has a nominal signal value Snom that corresponds to the center of the track; as already said, it is assumed that Snom = 0. In addition, the absolute value of the track signal has a maximum Sma * that corresponds to a maximum lateral (radial) deviation from the center of a track. A track error parameter D is defined as follows to normalize the absolute value to said maximum: D = | S I / S Under normal conditions, this value will appear more briefly as the track error parameter becomes larger. According to the preferred criterion proposed by the present invention, the track to be tested is considered to be defective if the track error parameter is greater than 0.5 for a time length of 60 μs or longer. Figure 4 shows a diagram of operations of another variant of the test method according to the present invention, which is preferred over the method described with reference to Figure 3. Identical reference numbers refer to identical or similar steps, which therefore, they will not be described extensively. If in step 103 the track being tested is found to be defective, the sequence number of this track is stored in a list in step 141, said list is stored in memory 25 and is called "defect list". primary. " For example, this is the case for the second test track 2T2 and for the third test track 2T3. Now, in contradiction with the method described with reference to Figure 3, it is not determined which adjacent tracks are affected: it is assumed that all tracks 2 in the area between the test track examined and the test track directly preceding it are "suspicious." This is also assumed for all tracks 2 in the area between the test track examined and the test track directly following it. These two areas together are referred to as the "suspicious area" 3T; Figure 4 shows two suspicious areas 3T2 and 3T3, which correspond to test tracks 2T2 and 2T3, respectively. Thus, each suspect 3T area consists of 2N tracks. In a step 142 the suspect area 3T is stored in a list which is known as an "alarm list" in memory 25. As already explained, although a distinction can be made between the test tracks already examined and the suspect tracks not still examined and there may be two different lists, whose contents are treated in different ways, it is preferable that the two lists are combined in a single list. In other words, it is preferable that the test tracks already examined and the suspect tracks not examined still be stored in a single list, which will be called an "alarm list". Subsequently, the control unit 22 returns to step 104. It will be evident that the control unit 22 of the video recorder 20 is ready much faster than in the case of the method illustrated in Figure 3, since the step 110 described above with reference to Figure 3. The alarm list (and the list of primary defects, if any) can also be implemented by means of an initially empty memory in which only the sequence numbers of the tracks are stored. relevant, or by means of a memory having a predetermined number of storage locations, each storage location corresponding to the sequence number of a given recording track. After step 105, the video recorder is ready to record information (video signals) on disk 1 in step 106. The writing process will be substantially identical to the standard writing process, with the proviso that the control unit 22 is adapted to read the alarm list (and, if applicable, the list of primary defects) in the memory 25 during writing and to skip the recording tracks that appear in said list. It will be evident that it is also possible to record a very fast information stream, for example, a digital video signal in real time, continuously without having problems due to possible spot defects. For undetected spot defects, which by definition are comparatively small, activates the error correction system to correct possible errors. For spot defects detected, simply skip the affected tracks and the suspicious tracks in the immediate vicinity. Furthermore, it will be evident that the method for testing the recording tracks of the recording disc, as proposed by the present invention, takes comparatively little time. Thus, in the proposed method, not only the tracks affected by comparatively large blemish defects 13 are skipped, but also the affected tracks are skipped only slightly by comparatively small blemish defects or those which are not affected. After completing the recording in step 106, when the video recorder 20 does not need to be immediately ready for further commands from the user, the video recorder 20 has time to more closely examine individual suspicious tracks of the alarm list in order to detect the dimensions of the stain defects of each of the test tracks specified in the list of primary defects. The process that follows may be identical to that described for steps 110 and 120 of Figure 3. If the test tracks and associated suspicious tracks were stored in the alarm list, it is also simple to examine all the tracks specified in this list of alarm. In a step 151, a first track number of a test track of the alarm list is read (or, if applicable, from a list of primary defects). In a step 152, similar to step 110 described above, the radial dimension X of the detected spot defect is determined and in a step 153, similar to step 120 described above, said radial dimension X is compared with a given threshold value M. As in the case of the third test track 2T3, if it is found that a detected spot defect 13 is larger than what is allowed, the control unit 22 proceeds to step 154, similar to step 130 described above. , to store the addresses of the relevant affected tracks in a list which will be referred to hereinafter as "secondary defect list" or "defect list". In a step 155, the control unit determines whether a next test track exists in the alarm list (or, if applicable, a list of primary defects) and, if that is the case, control unit 22 is reversed step 152. With a subsequent write command, the control unit 22 will read the list of defects in the memory 25 and skip the tracks that appear there. The defect list can be written to the relevant disk 1, which allows the test procedure to be skipped during the subsequent use of the disk. In an alternate variant step 142 is skipped, which means that in step 141 only the defective test tracks will be recorded in the list known as the "primary defect list". The writing process performed in step 106 will be substantially identical to the standard writing process, provided that the control unit 22 is adapted to read the list of primary defects in the memory 25 during writing and to skip the suspicious areas (3T2, 3T3) that correspond to the test tracks (2T2, 2T3) in this list. In a further modification of the present invention, the control unit 22 is adapted to monitor the track signal during a writing process as described hereinabove and to interrupt the writing process if it is found that the track signal indicates a test error so large that it may damage an adjacent track by the writing process. The criterion of interruption of the writing proposed by the present invention is a criterion similar to that of the track integrity described above but now with a higher value for the acceptance threshold. The decision to interrupt the writing process is taken when the error parameter of track D of the track signal is greater than 23 of a time length of 60 μs or greater. It will be apparent to one skilled in the art that the field of the present invention is not limited to the examples described herein and that various changes and modifications are possible without departing from the scope of the invention as defined in the appended claims. For example, the present invention has many advantages if only predetermined test tracks are examined in the test procedure, even if the test procedure is not based on the use of track signals, although it is recommended. Furthermore, in the method described with reference to Figure 4, it is possible to combine the list of primary defects and the alarm list in a single list in the method described with reference to Figure 4.

Claims (17)

CHAPTER CLAIMING Having described the invention, it is considered as a novelty and, therefore, what is contained in the following is redacted:
1. CLAIMS 1. A method for examining the presence of some defetio on a recording track (2) of a record carrier (1), in which the track to be examined is followed and the resulting track signal is monitored, and wherein the recorded track track is considered based on the characteristics of the resulting track signal.
2. 2. A method as recited in claim 1, wherein the engraving track examined is considered defective if the absolute value of the track signal has a value that exceeds a predetermined signal threshold for a predetermined time period or greater.
3. 3. A method as recited in claim 2, wherein the track signal has a nominal signal value of zero corresponding to the center of the track, and has a maximum value corresponding to a maximum lateral deflection with respect to the center of the track. a track, and in which a selected fraction level is chosen before said maximum value as the signal threshold, preferably the fraction previously selected is equal to approximately 0.5.
4. 4. A method as recited in claim 2 or 3, wherein said predetermined time period falls in an approximate range of between 50 μs and 75 μs, and preferably is about 60 μs.
5. 5. A method for examining the presence of stain defixes (12, 13) in a recording carrier (1), the method consists of the following steps: a) examining the integrity of the predetermined test tracks (2T) of the carrier engraving (1), preferably by means of a method such as those recited in any of the previous claims; b) examine the integrity of the tracks (2) adjacent to the relevant test track (2T2, 2T3) each time a defective test track (21, 2T3) appears in the test, in order to determine in this way the number (X) of tracks (2) affected by the same spot (12; 13); c) registering the relevant tracks (2) in a list of defeds each time the number (X) determined in step (b) is greater than the predetermined threshold value (M); d) store the list of defedos in the memory 25.
6. 6. A method as recited in claim 5, wherein each time a predetermined number (N) of tracks (2) is stripped between successive test tracks (2T), said number (N) is preferably equal to about 50 .
7. 7. A method as recited in claim 5 or 6, wherein the list of defedos is stored in the examined engraving carrier (1).
8. 8. A method for recording information, in particular real-time video, in a recording carrier (1) of the type having a multitude of concentric circular recording tracks (2), in particular a DVR disc, the method is composed of the following steps: - first, in an inspection phase, providing a list of defile tracks of shaded tracks by a comparatively large stain defender (13) by means of a method such as those recited in any of Claims 5-7; - later, recording information on the disc in a recording phase at the same time that the reference to said list of defedos is made, the recording tracks included in said list of defedos are skipped in the recording process.
9. 9. A method for examining the presence of spot defixes (12, 13) on a record carrier (1), consists of the following steps: a) examining the integrity of the predetermined test tracks (2T) of the recording carrier ( 1), preferably by means of a method such as those recited in any of Claims 1-4; b) register the relevant clues (2T2; 2T3) in a list of primary defects each time the inspection of the test track (2T2; 2T3) appears defeduosa and, in an opdonal way, register tracks (2) located in a suspicious area ( 3T2; 3T3) on opposite sides of the relevant test track (2T2; 2T3) in an alarm list; c) store the list of defedos and, if applicable, the alarm list in the memory (25).
10. 10. A method as recited in claim 9, wherein each time a predetermined number (N) of tracks (2) is skipped between successive test tracks (2T), and in which each suspect area always extends from the test track -, * «< fer, j relevant (2T2, 2T3) up to the test track that precedes it and the one that follows it directly, respec- tively, said number (N) is approximately 50 preferential.
11. 11. A method for recording information, in particular real-time video, in a recording carrier (1) of the type having a multitude of concentric circular recording tracks (2), in particular a DVR disc, the method is composed of the following steps: - first, in a primary inspection phase, provide a list of primary tracks of test tracks (2T2; 2T3) that have a defedo and, in an opdonal way, an alarm list of tracks (2) located in an area suspicious (3T2; 3T3) on opposite sides of the relevant test tracks (2T2; 2T3), by means of a method as recited in any of claims 9-10; - later, recording information on the disc in a recording phase at the same time that reference is made to said list of primary defedos and to said opdonal alarm list, the recording tracks included in said list of primary defedos as well as the tracks ( 2) located in a suspicious area (3T2; 3T3) on opposite sides of the relevant test tracks (2T2; 2T3), are skipped in the recording process; - later, to examine the integrity of the tracks (2) in said suspicious areas (3T2; 3T3) in a secondary inspection phase, in order to determine in this way the number (X) of tests (2) affected by the same defedo of stain (12; 13); - register the relevant tracks (2) in a secondary defile list every time the determined number (X) is greater than a predetermined threshold value.
12. 12. A method as recited in claim 11, wherein the list of secondary defilements is recorded on the examined engraving member (1).
13. 13. A method for recording information in a recording track (2) of a recording carrier (1), in which the resulting track signal is monitored and in which, based on the characteristics of the resulting track signal, stop if the engraving process continues or is suspended.
14. 14. A method as recited in claim 13, wherein the engraving process is suspended if the absolute value of the track signal has a value that exceeds a predetermined signal threshold for a predetermined period of time or greater.
15. 15. A method as recited in claim 14, wherein the track signal has a nominal signal value of zero corresponding to the center of the track, and has a maximum value corresponding to a maximum lateral deflection with respect to the center of the track. a track, and in which a selected fraction level is adopted prior to said maximum value as a signal threshold, said previously selected fraction preferably being equal to about 2/3.
16. 16. A method as recited in claim 14 or 15, wherein said predetermined time period falls in an approximate range of between 50 μs and 75 μs, and preferably is about 60 μs.
17. 17. A recording apparatus (20) suitable for recording information, in particular audio or video in real time, in a recording holder (1) of the type having a multitude of concentric drcular recording tracks (2), in particular an optical disc , whose engraving apparatus is composed of: - a control unit 22; - a writing / led unit (21) adapted to aim a laser beam on a track (2) of a engraving carrier (1) under the control of the control unit (22) and to redirect laser light reflected from the disk (1), and subsequently adapted to provide a track signal for the control unit ( 22), whose track signal was determined based on the reflected laser light; wherein the control unit (22) is adapted to carry out the methods as recited in any of Claims 1-16.