MXPA97008158A - Apparatus and method for determining a type of disc before reproducing the data of the di - Google Patents

Abstract

A type of disc in a playback device is determined exactly before the reproduction of the data. To determine whether the disc type is Compact Disc (CD) or Digital Video Disc (DVD), one step of the track on the disc is examined, while the difference between the Single Layer of DVD and the Double Layer of DVD is based on the reflectance values of the disk. When the disk type determined in this way is incorrect, an operation is performed to calculate the correct disk type based on the highest possibility of disk type after the initial (incorrect) decision. The process is carried out until the correct disk type is identical, or the disk determines that it is unusable.

Description

"APPARATUS AND METHOD FOR DETERMINING A TYPE OF DISC BEFORE REPRODUCING THE DISC DATA.

BACKGROUND OF THE INVENTION The present invention relates to producing data from a disk, and more particularly to the apparatus (and the corresponding method) which functions to quickly and accurately secure the type of disk from which the data is reproduced by a reproduction apparatus (or steps of reproduction) . It is evident that the popularity of a Disc of Digital Video (DVD) is growing very fast nowadays. Typically the DVD can be a single layer disc (DVD SL disc) with a data layer to record / reproduce the data or a Double Layer disc (DVD DL disc) that has two data layers. Both types of disc can be used interchangeably by means of a reproduction device (apparatus). In addition to the DVD, the data of a Compact Disc (CD) can also be played by this playback device. Therefore, at least three types of disc can be used by a single reproduction device. Even though the physical form (diameter) of each type of disc (DVD SL SL, DVD DL and CD disc) can be the same, each of these discs works with singular parameters (operating conditions) graduated by the playback device. This is due to the fact that the data formats and / or the internal disk structures for data storage are different between the VDV SL disk, the DVD DL disk and the CD, for example. As a result, the reproduction device that can employ any of the three aforementioned discs must ensure which type of disc is currently in use. A control data area is provided on the DVD where the data related to the disk type can be recorded. Similarly, on the CD, an area of TOC (Matter Index) is assigned to record, among other things, the data related to the type of disc. Therefore, it seems that it is possible to easily determine the type of disk loaded in the device, by simply accessing the control data area or the TOC area and retrieving (reading) the appropriate information in those areas. However, a problem is encountered when the playback device is capable of operating to read the data of the disk. Namely, in order to read the data correctly, it is necessary to initiate several servo circuits (impellers) in the playback device (such as a focusing servocircuit, a tracking servo circuit, a servo circuit and the like) to their proper states (graduations ). Unless these servo circuits are set (the appropriate operating conditions are set), the data can not be read, the control data area or the TOC area. For example, it is necessary to adjust the power of the laser beam or the gain of the amplification of the RF signal reproduced in the reproduction device before reproducing the data of the disc. If these parameters do not graduate correctly, the data can not be read. The type of disk, therefore, can not be determined using the seemingly simple approach cited above. Therefore, it would be preferable to determine the type of disc before graduating the necessary parameters in the reproduction device. In this regard, it is possible to use a trial and error method. However, after inserting the disk in the device, it will require a long time for the playback device to reach a state where the reproduction of the data is carried out. The situation certainly becomes even worse as the number of possible disk types increases.

There is therefore a need for a device and method that overcomes the aforementioned disadvantage.

OBJECTS OF THE INVENTION Therefore, an object of the present invention is to reliably determine a type of disk. Another object of the present invention is to determine a disc type for discs of different formats and / or data recording densities. A further object of the invention is to be able to begin reproducing the data of the disk quickly after the termination of the disk type.

COMPENDIUM OF THE INVENTION According to one aspect, the invention is defined by an apparatus for reproducing the data of a number of disks, wherein each disk is of the predetermined type. The apparatus includes a reproduction means for reproducing the data of a disk, a detection means for carrying out a detection operation for detecting the type of disk in such a way that the data can be reproduced from the disk correctly; and a graduation means for graduating the reproduction medium to a predetermined condition corresponding to another type of disc when the disc type has been mistakenly detected. The predetermined condition is selected, as a function of the detection operation, from at least two or three predetermined conditions. In accordance with another aspect of the invention, the apparatus includes a means for performing a differentiation operation for differentiating between a compact disc and a digital video disc such that the detection operation comprises this differentiation operation. According to still another aspect of the invention, the apparatus includes a means for carrying out a differentiation operation to differentiate between the first digital video disc having the registered data in two layers and a second digital video disc having the data recorded in a layer in such a way that the detection operation comprises this differentiation operation. According to still another aspect of the invention, the graduation means sets the reproduction means to the predetermined condition, establishing a number of predetermined parameters in such a way that the data can be reproduced from the disk correctly. These predetermined parameters include a focus of the beam or beam and / or the speed of the disk, for example.

BRIEF DESCRIPTION OF THE DRAWINGS The aforementioned objects, features and advantages, as well as those additional to the invention, will become more readily apparent from the following detailed description thereof which will be read together with the accompanying drawings, in which: Figure 1 is a functional diagram showing a representative structure of the disc reproduction apparatus, in accordance with the present invention. Figure 2 is a flow chart showing the operation of the disc reproduction apparatus of Figure 1. Figure 3 is a continuation of the flow chart of Figure 2. Figure 4A is a flow chart that works on Step S3 of Figure 2, enumerate the steps for the differentiation between a DVD and a CD. Figures 4B and 4C illustrate a principle behind DVD / CD discrimination.

Figure 5 is a flow graph that works in step S3 of Figure 2, listing the steps to differentiate between a DVD DL and a DVD SL. Figures 6A-6D illustrate operations of the capture means 5 and different signals according to the flow chart of Figure 5, to differentiate between the DVD DL and the DVD SL. Figure 7 is a first mode of the decision-making process to calculate a disk type with the highest possibility of success after the initial mis-detection of the disk type. Figure 8 is another modality of the decision-making process to calculate a disk type with the highest possibility of success after the initial wrong detection of the disk type. In all the Figures, the like reference numbers represent identical or identical components of the invention.

DETAILED DESCRIPTION OF THE PREFERRED MODALITIES The present invention will now be explained in detail with reference to the accompanying drawings.

Figure 1 is a functional diagram showing a representative structure of the disc reproduction apparatus according to the present invention. A disk 1 (which can be a CD, single layer DVD or double layer DVD, for example) is placed for rotation at a predetermined speed by a spindle motor 2. A tilt sensor 3 directs a light beam (produced by an integral LED), for example) on the disk 1 and receives the reflected light beam (acquired by an integral photodiode) to detect the inclination (slope) of the disk 1. The result of the detection is sent by the inclination sensor 3 to a CPU 15 as a tilt sum signal. In addition, a CD discrimination sensor 4 supplies a light beam (produced by an integral LED) to disk 1 and determines whether a pitch of the track on disk 1 is approximately 1.6 micrometers (i.e., disk 1 is a CD since the pitch of the DVD disc track is approximately 0.74 micrometer). A CD detection signal (indicating whether the disc is CD) is sent by the CD discrimination sensor 4 to the CPU 15. During the reproduction of the data, a pick-up device 5, comprising a laser diode and a photodiode, directs a laser beam (produced by the laser diode) to disk 1 and receives the beam of light reflected from disk 1 by the photodiode. Then, a preamplifier 6 amplifies an electrical signal received from the feedback device 5 (ie, the reflected light beam received by the photodiode of the feedback means 5 is transformed through a photoelectric conversion into a reproduction signal of the electrical data ) and sends the same to the equalizer 7. After processing the data reproduction signal to conform to the specified characteristics, the equalizer supplies the processed signal to a PLL circuit 8 which derives a clock signal therefrom. The derived clock signal, together with the data reproduction signal, is provided to a demodulator 9. The data reproduction signal is demodulated by the demodulator 9 after being synchronized with the clock signal. The output of the demodulator 9 is supplied to a synchronization signal separator circuit 10 and an ECC circuit 13. The separator circuit 10 of the synchronization signal extracts a synchronization signal and sends it to a CLD controller 11 (constant linear velocity). ) and an address decoder 12, while the ECC circuit 13 sends the demodulated data signal to the address decoder 12 after carrying out an appropriate processing operation to correct errors on the modulated side, if necessary. On the basis of the synchronization signal supplied from the synchronization separator circuit 10, the address decoder 12 generates an error corrected data address supplied from the ECC circuit 13. As shown in Figure 1, the decoded address is allowed. to the CPU 15. In addition, the CLV controller 11 under the control of the CPU 15 is capable of operating to control an impeller 14 of the spindle motor to drive the spindle motor 2. The spindle motor driver 14 also produces a spindle signal FG corresponding to the rotation frequency of the spindle motor 2. The spindle signal FG is provided to the CPU. The feedback means 5 is adapted to reproduce the data using a so-called three-beam method (when playing the data of the CD) and using a beam method (when playing the data of the DVD). In the acquisition means 5, the photodiode for reproducing the data is divided into four sections A, B, C and D, named representatively; and a photodiode to follow the CD is divided into two representative E and F sections. As illustrated in Figure 1, the preamplifier 6 sends the signals of the photodiodes A to F to a matrix circuit 16. The matrix circuit 16, among other things, combines (adds) the signals to the photodiodes A to D, and sends the added signal to a peak retention circuit 17 as the latching signal and sends the detected peak value to the CPU 15. In addition, the matrix circuit 16 calculates a so-called diagonal signal as (A + C) - (B + D) from the output signals of the photodiode sections placed diagonally in the feedback unit 5, in such a way that a focus error signal is generated. Furthermore, in a case where the disk 1 is CD, the difference (E-F) in the output signals from the sections E and F of the photodiode is calculated resulting in a tracking error signal. However, when disk 1 is from BVD, the tracking error signal is produced by a Differential Phase Detection (DPD) method as a function of the diagonal signal and the Engage signal. A servo processor 18 receives the focus error signal and the tracking error signal from the matrix circuit 16, and adjusts these signals appropriately as an output to the pickup driver 20. The pickup driver 20 (servo) is positioned to move the pickup unit 5 in the focus direction or the tracking direction in accordance with the focus error signal or the tracking error signal, respectively, while also working to adjust the pickup unit 5 in the radial direction of the disk 1. An EEPROM 19 is also shown in Figure 1. Among other things, the EEPROM 19 stores a Pl level (sldisco, slmodo) of the Hitch signal when the DVD disc data SL is played back in the SL mode (a mode where the parameters for the DVD SL disc are graded) and a Pl (didisco, dimodo) level of the Engage signal when the DL disc data is played back in DL mode (a mode in which the parameters for the DVD DL disc are graduated). These signals will be explained further below. Then, the operation of the disk reproduction device as illustrated in the functional diagram of Figure 1 and as described above will be explained with reference to the flow charts of Figures 2 to 4. In Figure 2, in step SI, the CPU 15 is programmed to activate the laser diode of the pickup unit 5 to generate a laser beam. As a result, the generated laser beam is directed towards the disk 1, where the reflected light is received by a photodiode from the feedback means 5. Then, at the output of the photodiode, it is supplied to the preamplifier 6.

Then, in step S2, the CPU 15 is able to operate to control the driver 14 of the spindle motor (via a CLV controller 11) to drive the spindle motor 2. In step S3, the CPU 15 performs the processing operation to discriminate the disk 1. This processing operation includes the step of distinguishing between the DVD and the CD and the step of distinguishing between DVD DL and DVD SL when the disk 1 is inserted into the playback device. The processing operations for discriminating between DVD and CD are shown in detail in the flow chart of Figure 4A and in Figures 4B and 4C. That is, the flow chart in Figure 4A illustrates some of the operations included in step S3 of Figure 2, while Figures 4B and 4C show the principle behind DVD / CD discrimination. When the coherent light is directed towards the diffraction grating formed in the disk 1 as shown in Figure 4B, the incident light is divided into diffracted light rays, viz., a so-called ray of light of order 0 that advances in the same direction as the incident light, and other rays of light diffracted in divergent directions including a so-called light beam of + first order, a ray of light of + third order, ..., a ray of light of higher order, a ray of light of first order, a ray of light of second order, a ray of light of a higher order. When the light is radiated to disk 1 as shown in Figure 5, the rays of light diffracted by an AO pit are reflected and returned according to a diffraction pattern, as shown in the Figures. In this case, the angle divergence from the zero order light beam depends on the pitch Pt of the track. When the pitch of the track is approximately 1.6 micrometers on a disk 1 (being one of the CD type), a beam IB of diffracted light of the first order is returned (reflects) as shown in Figure 4C. The angle? L represents the diffraction angle for the CD.

Alternatively, when the pitch of the track is about 0.74 micrometer on disk 1 (being of the DVD type) a beam 1C of diffracted light of the first order is returned (reflected) as shown in Figure 4C. The angle T2 represents the diffraction angle for the DVD that is greater than? L. Based on the output of the CD discrimination sensor 4, the type of disk 1 can be identified. Since the angular difference between the diffraction angle? L and the diffraction angle T2 is typically approximately several degrees, the type of disk 1 can be secured with great reliability.

Turning now to the flow chart of Figure 4A, in step S91, a representative memory storage marked "N" to store the number of times that the detection described below is carried out starts at 3. In step S92, the CD detection signal from the CD discrimination sensor 4 is checked by the CPU 15. When the CD detection signal contains information indicating that the measured track pitch corresponds to approximately 1.6 microns, the process progresses to step S93. In step S93, after receiving and processing the CD detection signal, the CPU 15 executes the appropriate instructions to indicate that the disk 1 is a CD. In step S92 if the CPU 15 determines that the information carried by the CD detection signal is not indicative of the CD disc type, the CPU 15 functions to execute instructions to temporarily assume that the disc type is DVD. Accordingly, in this case, the process proceeds to step S94 and the value in N is decreased by one. Then, a determination is made in step S95 of whether the value in N is equal to 0. If N does not contain 0, the process returns to step S92 and is again checked at the output from the CD discrimination sensor 4. It is evident that a time interval has elapsed for when the output of the CD discrimination sensor 4 is checked again (ie, when N is less than 3, for example). Since the disk 1 continues to rotate during this time interval, the laser beam has a greater possibility of being directed to a different position on the disk 1 than before. The discrimination sensor 4 receives the reflected light beam from the new disk area 1 and carries out the detection processing on the newly reproduced data. Therefore, even if the disk type is not detected as CD during the first detection due to contamination and possible disk imperfection in the disk area illuminated by the laser diode, disk 1 is detected correctly during the second detection ( based on the data reproduced from the new position on disk 1), provided, of course, the disk type is CD. In this case, the CPU 15 is programmed to carry out the appropriate instructions for the CD disc type. When the CD discrimination sensor 4 does not send the CD detection signal the second time (or the CD detection signal does not contain information as processed by the CPU 15 indicating that the disc 1 is CD), the detection signal of the CD is checked once more and the process returns to step S92. Consequently, three detection operations according to this representative embodiment of the invention are carried out. If in step S94 N is equal to 0, the processing in step S96 is carried out in such a way that the type of disk 1 is graduated to DVD. In this case, the details of the processing operation for differentiation between the DVD DL disc and the DVD SL disc, are shown in the flow chart of Figure 5. In particular, in step S101, the CPU 15 executes the instructions to calculate a threshold level PIr? defined by the following equation: PIrl = ((Pl (didisco, slmodo) + Pl (sldisco, slmodo)) / 2 = ((Pl (didisco, dimodo) - PIref) x (a / b) x (c / d) + ((Pl (sldisco, slmodo) - PIref)) x (e / f) x (1/2) + PIref (1) Now will explain equation (1). On the DVD, when an SL disc is compared to a DL disc, it will be appreciated that the SI disc has a higher reflectance value (ie, the intensity of the reflected light beam is greater) than that of the DL disc. The threshold level PIr? it is used for differentiation between the SL disk and the DL disk based on a difference in the reflectance value. In particular, a focus error signal (as shown in Figure 6C) deviates from its zero level as the objective lens of the unit capture 5 (marked in the Figure as a so-called OPT) is gradually brought closer to disk 1 (as shown by the distances DQ, DI, D2, in the direction of the arrow (the direction of focus) to its position optimum (the distance D ^ in Figure 6A) The movement of the pick-up medium 5 is carried out through the pick-up driver 20 by sending a driving voltage, as shown in Figure 6B, then in accordance with the Figure 6D, the hooking signal becomes maximum when the focus error signal (Figure 6C) crosses approximately the zero level, since the Si disk has a reflectance value larger than the DL disk, the level of the latching signal (Pl) is greater for the SL disk than for the DL disk in the vicinity of the zero crossing by the focus error signal, as illustrated in Figure 6D (ie, Pl (sldisk, slmodo) is greater than Pl (didisco, slmodo)). The threshold level PIr? it is pre-learned at an intermediate value between the Engage signal of the SL disk (PI (sldisco, slmodo)) and the Engage signal of the DL disk (Pl (didisco, slmodo)). As mentioned above, the EEPROOM 19 stores the Pl (sldisco, sl odo) of the Engage signal when the DL disc data is played in the DL mode (exclusively the DC component, a so-called level of PIref) v stores the Pl (didisco, dimodo) of the Engage signal when the data of the SL disc is played in the SL mode (also excluding the PIref level). The threshold level PIr? which is selected as the approximate intermediate value between Pl (sldisco, slmodo) and Pl (didisco, slmodo) is adequate to differentiate between the two. The values of the Hitch signal however may vary as a function of the laser power or its gain or may depend on whether the servo-focus is connected to the playback device. Let a relation of LPga, and LP ^ L be the following: LPSL: LPDL = a: b where LPga is a parameter of the SL mode and LPjL is a parameter of the DL mode related to the laser power. Similarly, let a relation of G¡SL to GGJ be the following: GSL: GDL = c: d where GSL is a parameter of the SL mode and G ^ L is a parameter of the DL mode related to the gain of l. In addition, let the focus-to-focus-to-focus-to-focus-to-focus ratio be the following: Focus-off-focus-PI: focus-switching-point = e: f where focus-focus-is a signal level of engagement when the servo-focus is disconnects, and PI focus switching is a level of the Hitch signal when the servo approach is connected to the playback device. Based on the above, the maximum level of the Pl (didisco, slmodo) in a case where the DL disc is played in the SL mode, is expressed by the following equation: Pl (didisco, slmodo) = (Pl (didisco, dimodo). PIref) x (a / b) x (c / d) x (e / f) + PIref ... (2) In addition, the maximum level of the Pl (sldisco, slmodo) of the SL disk is expressed by the following equation: Pl (sldisco, slmodo) = (Pl (sldisco, slmodo) - PIref x (e / f) + PIref ... (3) Then it follows that equation (1) can be obtained from equations (2) and (3) in such a way that any of the changes in the aforementioned parameters (which depend on a condition as stated above) are taken In order to select the threshold level PIrl- That is, as will be appreciated from equation (1), the relationships of these parameters are used instead of their absolute values to remove any effect on the threshold level PIr? of variations in laser power, etc. Continuing with the description of Figure 5, after PIr calculations are carried out? previously described in step S101, the pickup means 5 (OPT) initially moves downward (i.e., in a direction away from the disc 1) and is then stopped by the pickup driver 20 in steps S102 and S103, respectively. At this point (ie, when the OPT is down), the level of the latch signal is stored in a memory storage marked "PImax" in step S104, thereby initiating the p ^ max * Then, the pick-up driver 20 starts by moving the pick-up means 5 (OPT) upwards (i.e. towards the disc 1) in step S105; and a synchronizer is graduated during a predetermined time interval in step S106. After the synchronizer is graduated, in step S107 the CPU 15 stores the level of the latch signal in memory storage marked representatively "PIX" and where "x" indicates the number of the sample. In step S108, the value in PImax and PIX are compared; and if PIX is greater than PImax, then the value in PImax is replaced with the current value of PIX in step S109. The above-mentioned process in steps S108 and S109 is repeated until the predetermined time interval is exceeded (as checked by the synchronizer in step S110). As a result, the maximum level of the latching signal is obtained and stored in PImax. The level of the maximum latch signal (ie, the value of PImax) is compared (in step Slll) with the level of the reference latch signal stored in PIr ?. If the level of the maximum latch signal is greater than the level of the reference latch signal (i.e. PImax> PIr?), Then the disc type is graded as DVD SL (step S112); whereas if the level of the maximum latch signal is less than the level of the reference latch signal (i.e. PIma? <PIrl) 'then the disc type is graded as DVD DL (step S113) as has illustrated graphically in Figure 6D. Turning now to the description of Figure 2, after carrying out the disc discrimination operation as mentioned above with reference to Figures 3 to 6, the process proceeds to step S4 of Figure 2, where the CPU 15 initiates a memory storage marked representatively "Disk of Type of Retry". The Retry Type Disk stores an account value for the number of times the disk type tries to be secured exactly in the initiation condition. In step S5, the CPU 15 performs the various operations to set the system parameters according to the result of the disk discrimination in step S3. That is, in step S3, it is determined whether the type of disc 1 is DVD SL, DVD DL or CD, so that according to the result of this determination, the power of the laser diode of the feedback means 5, the gain of the system and similar factors are correspondingly graduated as required for this specific disc type. In step S6, the CPU 15 starts a memory storage marked "Focus Retry". The "Focus Retry" maintains an account value for the number of times the servo-focus (connected) is activated during the start-up of the device. In step S7, a synchronizer is set by the CPU 15 which also controls the servo processor 18 to connect the servo approach in step S8.

As stated above, the output signals from the photodiode sections A-D (as further processed by the preamplifier 6) are calculated in the matrix circuit 16, the focus error signal based on these is generated. exit signs. Then, the focus error signal is supplied to the servo processor 18 to control the pickup driver 20 (as a function of the focus error signal) which adjusts the pickup means 5 in the focusing direction, as illustrated in FIGS. Figures 1 and 6 (A). As further shown in Figure 2, it is determined in step S9 whether the servo approach is latched (correctly graded). If it is not, the process then proceeds to step S10 where the CPU 15 operates to execute the instructions necessary to make sure that the synchronizer (as graduated in step S7) has expired (it has exceeded a predetermined time interval). If the synchronizer has not yet expired, the process returns to step S9 and steps S9 and S10 are repeated. When the servo approach does not latch (as determined in step S9) and the synchronizer has exceeded the predetermined time interval (as determined in step S10), the process proceeds to step Sil where the CPU 15 controls the servo processor. to disconnect the servo approach. In this case, in step S12, the account value of the Focus Retry (initially graduated to 0 in step S6) is increased by 1. Then, it is determined in step S13, if the account value of the Focus Retry is equal to 3. In the present example, since the Focus Retry is 1, a "NO" decision is made and the process proceeds to step S14. In step S14, the CPU 15 controls the servo processor 18 to move the capture means 5 in the direction of the outer circumference (periphery) of the disk 1. After that, the process returns to the step S7 in such a way that the synchronizer is graduate once more and the servo approach is connected in step S8. In the two steps S9, S10, the servo-locking interlock operation is attempted and waited until the synchronizer exceeds the predetermined time interval if the focus on the apparatus is not established. In a case where the servo approach does not lock, the servo approach is again switched off in step Sil and the count value of the focus retry is increased by one. In accordance with the exemplary embodiment of the present invention, the operation of connecting the servo-focus is performed three times when the servo-focus is not locked by the time the synchronizer expires during each attempt. If the third attempt can not produce the servo approach, the decision "YES" is made in step S13, and step S15 is carried out to calculate, with great probability, the type of disk. Namely, as mentioned above, the steps as shown in the flow chart of Figure 4A are carried out to process the output signal (the CD detection signal) of the CD discrimination sensor 4. so that a differentiation can be made between a CD or a DVD. If necessary, by carrying out the steps in the flow chart of Figure 5, you can determine whether disk type 1 is DVD DL or DVD SL. With reference to the two previous operations to be decisions as illustrated in Figures 4A and 5 (ie CD versus DVD, and DVD disc SL versus DVD DL), the differentiation between the DL disc and the Si disc is more likely of being wrong. As a result, in one embodiment of the present invention, a calculation method is carried out in step S15, as shown in Figure 7. In particular, according to Figure 7, when the type of disk in the device of reproduction has been determined to be DVD (in accordance with the operation in Figure 4A) and then SL (in accordance with the operation in Figure 5), the appropriate parameters that correspond to the determined type of disc are graded (DVD SL) . Then, an attempt is made to lock the servo approach. When three attempts are unsatisfactory (that is, the servo approach can not be locked three times) it is decided and the previous determination on the disk type was erroneous. Therefore, it is evident that the type of disk 1 has to be DVD DL or CD in the exemplary mode. In this situation the determination of whether the disc type is DVD DL or CD is based on the possibility of making an erroneous decision between these two types of disc. In the present case, the erroneous decision is more likely to be made in the determination of DL / SL (Figure 5) in the determination of DVD / CD (Figure 4A). In other words, the information that is provided by the CD detection signal from the CD discrimination sensor 4 is considered to be reliable. In view of this, as shown in Figure 7 when the first decision on the disk type has been wrong (DVD SL) the probability is greater that the disk type is DVD DL than CD. Therefore, the CPU 15 graduates the appropriate parameters corresponding to the DL disk based on a decision that DVD DL has the best chance of being the correct disk type after the first incorrect decision has been made.

However, if the servo approach still can not graduate after three attempts, indicating that the disk type is not DVD DL, then it is determined that disk 1 is CD. The appropriate parameters are then graduated for the CD as the type of disk with the second highest probability. The decision-making process described above based on the possibility of an erroneous determination for the representative disc types DVD SL, DVD DL and CD is illustrated in a first row (from left to right) in Figure 7. In this case the type Disk was initially determined as DVD SL. A second row in Figure 7 illustrates the process of making decisions when the initial incorrect decision on the disk type has been DVD DL. In this situation, the probability is high that the disc type is DVD SL (due to the higher reliability of the detection by the CD discrimination sensor 4, as mentioned above.) Therefore, the following type of disc is selected as DVD SL (with the CPU 15 setting the corresponding parameters) while the CD is selected last if the servo approach can not be locked for the DVD SL It will be appreciated that the difference in the reflectance values between DVD DL and CD is greater than between DVD SL and CD The fact that DVD DL has been mistakenly considered as being CD (or on the contrary, the CD is mistakenly considered as being DVD DL) means that decisions based on the passage of the track and on the reflectance values have been both incorrect, since the probability that these two decisions have been wrong is small, when the type of disk has been determined to be CD incorrectly, there is a greater possibility the disk type discrimination based on the reflectance value is correct. Therefore, according to a third row in Figure 7, the second type of disc of greater possibility in this representative mode is the DVD SL, and the next type of disc of greater possibility is the DVD DL. According to another embodiment of the present invention, Figure 8 shows a decision order for disc type discrimination when there is a greater possibility of error between DVD and CD disc types, as occurs in some reproduction devices. When the initial decision has been incorrect that the disc type is DVD SL, a probability that the disc type is CD is high, which has a refelectance value close to the reflectance value of the DVD SL. In other words, if the type of disc in the playback device is DVD DL, then the disc type discrimination based on the pitch of the track (using the CD discrimination sensor 4) and / or the discrimination based on the Reflectance values are considered as being erroneous. Since the probability that only one of them is wrong is higher than the probability that both are erroneous, giving preference to CD as the type of disk. Then, when it is determined that the disk type is not CD, the remaining disk type is set to DVD DL. This operation is illustrated in the first row of Figure 8. It will be appreciated that the order to make a decision in the aforementioned case is different from the order to make decisions in the case where the wrong discrimination is most easily made between the DVD DL and DVD SL as seen by comparing Figure 7 and Figure 8. Continuing with the description of Figure 8 and a second particular row, when the disk type determination initially considered as being DVD DL has been erroneous, the disk type is either DVD SL or CD. If the disc type is CD, it means that not only the DVD / CD discrimination is wrong, but also that the DL / SL discrimination using the refractive values has been done incorrectly. Therefore, based on the possibility that a disc type discrimination operation (between DVD and CD) is correct instead of both being incorrect, the parameters on the playback device are graded for the DVD SL. Then if it is not DVD SL, the type of disk is determined as being CD. In addition, according to Figure 8, when the initial determination has been incorrect of which type of disc in the playback device is CD, the probability that the disc type is DVD SL that has the reflectance value closest to CD that DVD SL is high. Therefore in this case, it is decided that the disc type is not CD but DVD SL. Then if the disk type is not DVD SL (because the servo-focus can not be graded) the parameters for DVD DL are set. As a result of the aforementioned operations carried out in step S15 of Figure 2 and as explained in detail in Figures 7 and 8, the type of disk with the highest probability is calculated. Next, in step S16 in Figure 2, the value retained in the Type of Retry Disk is increased by one such that in the present case it becomes 2. In step S17 it is determined whether the updated value is less than 3. In the present case, since the value is less than 3, the process returns to step S5 and processing to graduate the parameters corresponding to the disk type as calculated in step S15 is carried out once more . Then, similar to the foregoing, the servo approach is connected in step S8 and checked if it is locked in step S9. If the servo approach can not be latched after the parameters corresponding to each type of disk have been tried three times, a decision is made in step S18 that the disk in the playback device is unusable. Returning to step S9 in a case where the servo approach is locked, the process proceeds to step S19 (Figure 3) where memory storage marked representatively as "CLV Retry" is initiated. He CLV Retry stores a counter for the number of times the CLV servo is connected. In step S20, the CPU 15 controls the CLV controller 11 to connect an approximate servo circuit to operate the spindle motor 2. Then, in step S21, the CPU 15 controls the servo processor 18 to connect a tracking servo circuit and also controls the CLV controller 11 to connect the CLV servo circuit instead of the approximate servo circuit in step S22. In addition, in step S23, the CPU 15 sets a synchronizer and in step S24 determines whether the CLV servo circuit is latched. When the CLV servo circuit is not latched, it is determined in step S25 whether the synchronizer has exceeded the predetermined time interval. If not, the operation in step S24 continues to be carried out. The operations in steps S24, S25 are repeated until the synchronizer expires while the CLV servo circuit is not in the latched state. The process then proceeds to step S26 where the CPU 15 connects the approximate servo circuit again instead of the CLV servo circuit. Then, after disconnecting the tracking servo circuit in step S27, the CPU 15 increases the count value retained in the CLV retry in step S28. In step S29, it is checked if the updated account value is equal to 3. If so, the process proceeds to step S30 where the CPU 15 moves the pickup means 5 to the outer periphery and changes the locking position of the CLV servo circuit to a different position. Then, the process returns to step S20 and the corresponding steps are repeated as described above. If the CLV servo circuit can not latch after three attempts within the specified time interval, it is checked in step S31 if the value of the disk type Retry is less than 3. If so, neither the servo circuit The CLV servo circuit or approach can not be locked after the parameters corresponding to each of the three types of disk have been consecutively graded. Accordingly, in that case, the process proceeds to step S36 and the disk is considered as being unusable. When the Disk Type Retry is less than 3 in step S31, the process proceeds to step S32 and the operations for calculating and grading the disk type are carried out based on the possibility of wrong disk type discrimination. The operations are the same as in step S15 which is described above with reference to Figures 7 and 8. Then in step S33, the disk type retry is increased by 1 and the focusing servo circuit is turned off in the Step S34. In step S35 the CPU 15 moves the pickup means 5 to its base position. Then, the process returns to step S5 (Figure 2) and the operations to set the parameters corresponding to the type of disk calculated in step S32 as well as to lock the focusing servo circuit are carried out as described above with reference to Figure 2. That is, when the CLV servocircuit can not be locked, even when the focusing servocircuit has been locked, it is considered that the type of disc has been determined erroneously and consequently the operations to lock the focusing servocircuit and the CLV servo circuit is carried out again. When the CLV servo circuit is determined to be latched in step S24 (Figure 3), the focusing servo circuit and the CLV servo circuit both latch. In this case in step S37, the CPU 15 controls the servo processor 18 to connect the servo circuit. In step S38, the addresses received from the address decoder 12 are stored by the CPU 15 confirming the continuity of the addresses in step S39. Finally, disk 1 is reproduced in step S40. In the above, DVD and CD disc types have been described representatively. It will be understood, of course, that other types of disk (as well as a different amount thereof) may be used to reproduce the data Having described specific embodiments of the invention with reference to the accompanying drawings, it should be understood that the invention is not limited. to those precise modalities Therefore, various changes and modifications may be made by those skilled in the art without departing from the scope or spirit of the invention as defined in the appended claims.

Claims (21)

R E I V I N D I C A C I O N E S:

1. An apparatus for reproducing data from one of a number of disks, each disk being of a predetermined type, comprising: a reproduction medium for reproducing the data of a disk; a detection means for carrying out a detection operation to detect the type of disk in such a way that the data can be reproduced from the disk correctly; and a graduation means for graduating the reproduction medium to a predetermined condition corresponding to another type of disc when the detected type of disc has been detected erroneously, the predetermined condition is selected as a function of the detection operation, hence minus two other predetermined conditions.

The apparatus according to claim 1, further comprising means for performing a differentiation operation for differentiating between a compact disc and a digital video disc such that the decision operation comprises the differentiation operation.

3. The apparatus according to claim 1, further comprising a means for carrying out a differentiation operation to differentiate between a first digital video disc having the recorded data in two layers and a second digital video disc having the data registered in a layer such that the detection operation comprises the differentiation operation.

The apparatus according to claim 1, wherein the graduation means graduates the reproducing means to the predetermined condition, establishing a number of predetermined parameters in such a way that the data can be reproduced from the disc correctly.

The apparatus according to claim 4, wherein the predetermined parameters include one of a beam focus and a disk speed.

The apparatus according to claim 1, wherein the graduation means graduates the reproduction means to the predetermined condition when the reproduction means can not reproduce the detected disk data.

The apparatus according to claim 1, wherein the graduation means sets the reproduction means to the predetermined condition when the reproduction means unsuccessfully attempts to reproduce the data from the detected disk a predetermined number of times.

The apparatus according to claim 1, further comprising means for establishing the disk as usable when the reproduction means tries unsuccessfully to reproduce the data of a disk a predetermined number of times for this type of respective disk.

9. The apparatus according to claim 1, wherein each disk has a different data format.

10. The apparatus according to claim 1, wherein each disk has a data recorded in a number of different layers.

11. The apparatus according to claim 1, wherein each disk has a different data record density.

12. A device for determining a type of disk from which the data can be reproduced, comprising: means for detecting the type of disk in such a way that the data can be reproduced from the disk correctly; and a means for selecting a second disk type for the disk when a first disk type has been mistakenly detected, the selection being based on a provability of the disk being the second type of disk after the erroneous detection of the disk as being of the first type of disk.

13. The device according to claim 12, wherein the disk is one of a compact disk, a digital video disk first having the data registered in one layer, and a second digital video disk having the data registered in it. at least two layers.

14. A method for determining a type of a disk from which the data can be reproduced, comprising the steps of: detecting the type of disk in such a way that the data can be reproduced from the disk correctly; and selecting a second type of disk for the disk when the first type of disk has been mistakenly detected, the selection being based on a probability that the disk is the second type of disk after the erroneous detection of the disk as being the first type of disk.

The method according to claim 14, further comprising a differentiation between a compact disc and a digital video disc such that the detection step comprises the step of differentiation.

16. The method according to claim 14, further comprising a differentiation between the first digital video disc having the data registered in two layers and a second digital video disc having the data registered in a layer in such a way that the detection step comprises the step of differentiation.

The method according to claim 14, further comprising setting a number of predetermined parameters for the first and second types of disk in such a way that the data can be reproduced from the disk correctly.

18. The method according to claim 17, wherein the predetermined parameters include one of a beam focus and a disk speed.

19. The method according to claim 14, wherein the second type of disk is selected when the data can not be reproduced from the disk. The method according to claim 14, wherein the second type of disk is selected after unsuccessfully attempting to reproduce the data from the disk a predetermined number of times. The method according to claim 14, further comprising setting the disk as unusable after unsuccessfully attempting to reproduce the disk data a predetermined number of times for the first and second disk types.