CN100380491C

CN100380491C - CD identification method

Info

Publication number: CN100380491C
Application number: CNB2005100752381A
Authority: CN
Inventors: 陈志豪
Original assignee: Via Technologies Inc
Current assignee: Via Technologies Inc
Priority date: 2005-06-07
Filing date: 2005-06-07
Publication date: 2008-04-09
Anticipated expiration: 2025-06-07
Also published as: CN1710659A

Abstract

The present invention relates to a method for identifying the CD, which judges the kind of the source CD within the moving period of an optical pickup. The present invention has the steps that a first focusing error signal is obtained by detection, wherein the valley value of the first focusing error signal is smaller than a first threshold value, and then, a peak value of a second focusing error signal which is larger than a second focusing error signal of a second threshold value is detected within the preset time when the first focusing error signal is obtained, or else, the peak value of the second focusing error signal which is larger than a third threshold value is detected from the preset time to the moving period of the optical pickup. In addition, if the peak value of the second focusing error signal of the third threshold value is not measured, the source CD is a single-layer disk. Accordingly, the optical disk drive can correctly judge whether the kind of the source optical disk is a single-layer disk, a double-layer disk of a DVD, and one of the SACD double-layer disk.

Description

CD identification method

Technical field

The invention relates to a kind of CD identification and double-layer CD sheet method of discrimination, particularly relevant for time of occurrence and the CD identification method of size with differentiation CD-RW discsCD-RW kind according to focus error signal.

Background technology

Along with the continuous lifting of Information of Science and Technology level, various Storage Medias obtain exploitation in succession, in the hope of more suiting numerous consuming public's user demand.The visible Storage Media in market is CD-RW discsCD-RW (CompactDisk at present; CD), it is the Storage Media that utilizes luminous energy to keep a record and read, have high record density (capacity is big), noise is little, the life-span is long, volume is little, easy to carry, can substitute arbitrarily, advantage such as cost is low and can not be subjected to that surface dirt influences when reading, its usable range is quite extensive, the scope that can write down and read comprises literal, figure, image, sound, video signal and animation etc., not only become the people's livelihood consumer goods of music, film, recreation, more become the topmost Storage Media of computing information today.Generally speaking, existing Storage Media product can generally be divided into three types according to its record different with read functions:

1, only reads type (Read Only) CD-RW discsCD-RW: for example compact disc (CD Audio), compact disc read-only memory sheet (CD-ROM), video CDs (CD Video), digital audio-video CD-RW discsCD-RW (DVD-Video) and digital CD-RW discsCD-RW (DVD-ROM) or the like.

2, writable disposable type (Write Once And Read Only) or title recordable type (Recordable): for example can write down dispensable mould CD-RW discsCD-RW (CD-R) or the like.

3, rewritable type (Rewritable) or claim erasable type (Erasable): for example magneto-optic video disc (MO), miniature light video disc (MD), phase change CD-RW discsCD-RW (PD), rewritable type CD-RW discsCD-RW (CD-RW) and digital rewritable type CD-RW discsCD-RW (DVD-RAM) or the like.

Wherein, only read the type CD-RW discsCD-RW and be mainly used in making audio compact disc, video disc etc.; Writable disposable type CD-RW discsCD-RW only can be once write activity, do not possess the erasable function, mainly be applicable to the data that record needs long preservation can not be disappeared and again, as the foundation of secretarial document, Graphic Documentation, medical history information etc.; Rewritable type CD-RW discsCD-RW then possesses the function that can repeatedly write down, read with wiping.After occurring digital audio-video laser disc product DVD of new generation in recent years, because more traditional CD-RW discsCD-RW has many advantages, for example because the memory capacity of DVD is seven times of compact disc read-only memory sheet at least, can reach 20 times at the most, therefore capacity is bigger, and the audio-visual quality of DVD CD-RW discsCD-RW is excellent, its horizontal resolution is (the video recording analysis ability far surpasses VCD) up to 500, captions show 32 kinds, number of channels reaches eight and (can hold multi-lingual, multinational captions) etc., showing that DVD is better than original CD product connecing, expecting that generally DVD CD-RW discsCD-RW in the several years will definitely become the main flow commodity in laser disc market gradually.

In addition, a kind of Storage Media with the music video disc new spec that is called SACD (Super Audio Compact Disc) is after the invention of CD, successfully surmounts the new product of CD recording quality.The sampling frequency of SACD is up to 2822.4MHz, it is 64 times that general CD 44.1KHz takes a sample, and therefore the SACD frequency range also makes SACD improve original CD music and gives the chill stereotype of people, and present with finer and smoother, more details, more soft sound especially up to more than the 100KHz.Further, the record type of SACD is to record with DSD recording technology (Direct Stream Digital) mode, the PCM record type of forgoing traditional, with the high sampling mode of all signals with 2.8224MHz (being 64 times that CD 44.1kHz takes a sample), that is per second 2,800,000 sub-samplings, with 0 and 1 continuous quantization, can listen the dynamic range of frequency domain to be about 120dB, may include the about 1000kHz of frequency domain, directly (simulation is analogy simulation, below all be called simulation) the music signal waveform with the mode changing pulse be the numeral (numeral is numerical digit, below all be called numeral) signal, just so-called " directly bit element flow numeral ", because store music with the space that is four times in CD nearly, therefore can provide more outstanding sound effect, add sampling number of times height, so the waveform of taking a sample is very round suitable, relatively therefore take a sample waveform very near original analog waveform near original analog waveform.

In addition, SACD is not owing to adopt multidigit unit, so can save the bit transitions program, issuable distortion and noise have been reduced because of digital filtering, and be subjected to the influence of power supply or external disturbance owing to easy as multidigit metasystem (bit is healed the higher position more easily), therefore quality can be more stable in theory, and SACD also can hold multichannel and image, the tonequality of SACD multichannel has comprised 6 independently tracks, each track can be read and not pass through any compression and complete DSD specification (Full DSD Bit Rate), with respect to general DVD, because through overcompression, so only can hear the tonequality of 96K/24Bit.Because the location of SACD self and a bit (1bit) quantize the succinct and advantage of DSD direct data flow process at technical elements, therefore the salty SACD of recognizing has preferable tonequality.

On the other hand, the data access technology of CD-ROM device also promotes along with the Storage Media variation, and its primary structure comprises to be responsible for stablizing rotating mechanism, the control circuit of controlling this optical read/write head and signal processing circuit of rotation or the like by reading on the CD-RW discsCD-RW with the optical read/write head of tracer signal, mobile this optical read/write head to driving mechanism, the maintenance CD-RW discsCD-RW of ad-hoc location.Wherein, optical read/write head is the key part and component of CD-ROM device, it is formed subsystem and comprises the optical system of being made up of laser light source, collimation lens, collecting objective, cylindrical lens, OPTICAL SENSORS (or claiming optical receiver) etc., the focusing of being made up of Liar group, elastic support and power and mechanical energy transducer follows rail system (or being categorized as mechanical drive system), and the electromagnetic driving system of being made up of focus servo, rail searching servo, circulation orbital servo and Spindle Motor control etc. (or being categorized as servo-control system).One carry at this, because factors such as rotation and exterior vibration can influence the mechanical precision of CD-ROM device, the trajectory generation that causes laser light up and down with about skew or rotation rock, so CD-ROM device needs respectively to focus on and follows the rail action to drive laser point light accurately in alignment with CD-RW discsCD-RW groove (pit and land).

At present several focusing and modification methods that comparatively extensively adopt, comprise method of astigmatism (astigmatic), critical angle method (critical angel), right spot method (spot size), cutter lot or luck by which people are brought together (knife edge) and Fu Kefa (foucault) etc., be by comparing in positive burnt, near burnt focusing result burnt and far away in the formed reception difference of OPTICAL SENSORS, to obtain focus error signal (focusing error signal; FES), feedback by this and produce voltage and go to drive focus actuator (focus actuator) and revise focusing accuracy, and then provide servo-control system to adjust luminous point, wherein because near nearly Jiao that object lens are caused when moving up and down focus point will make focus error signal produce the positive and negative variation of amplitude with Jiao far away, so this focus error signal curve of a S shape normally; The rail that follows commonly used then comprises i-beam push-pull method (single beam), three-beam method (three beam) and dithering (wobble) etc. with modification method, be respectively by the received light intensity difference of OPTICAL SENSORS of relatively using sensitization in four fens with six fens sensitization, to obtain tracking error signal (tracking error signal; TES), as following the foundation of rail correction, wherein this tracking error signal also has the sigmoid curve that is similar to this focus error signal, produces voltage with back coupling and goes driving actuator by this.

From the above, focus error signal in wave form varies that OPTICAL SENSORS presented respectively shown in Figure 1A and Figure 1B, wherein, Figure 1A is that the focus error signal value of method of astigmatism changes synoptic diagram, comprise nearly burnt zone 110, positive burnt zone 120 and burnt zone 130 far away, waveform segment in these zones is to represent nearly Jiao, the focus error signal value when positive Jiao is extremely far burnt to change in regular turn, and positive focus 140 shows not have focusing error this moment, and positive burnt regional 120 width are that suitable CD-RW discsCD-RW data reads the scope on opportunity.Figure 1B is that the focus error signal value of cutter lot or luck by which people are brought together changes synoptic diagram, comprise nearly burnt zone 150, positive focus 160 and burnt zone 170 far away, waveform segment in these zones is to represent nearly Jiao, the focus error signal value when positive Jiao is extremely far burnt to change in regular turn, and just focus 160 demonstrations do not have focusing error at this moment.

Further, aforementioned each focus method all can produce focus error signal, and signal waveform all is similar sigmoid curve, when object lens arrive correct focal position, the focus error signal value is all zero, and in positive dirction and negative direction apart from correct focal position, each can produce the maximal value of a positive and negative focus error signal, promptly be respectively focus error signal peak value and valley, curve between two extreme values then is near linear, therefore can use linear control method to reach the job requirement of focus servosystem in this linear zone.Wherein, in the control loop design in this linear zone; usually the characteristic that can utilize focus error signal and RF signal (radio frequency) is to judge whether correct focusing, and wherein the waveform of RF signal is a secondary parabolic curve under shed, that is sinusoidal wave positive half cycle.When optical read/write head makes that by the bottom is up mobile the RF signal is higher than a certain critical value, then expression focuses on the range of linearity that has entered the S curve, and the RF signal can reach maximal value when correct focusing, therefore can judge whether near the correct focusing that the focuses on zero cross-point FZC (focus zero crossing point) of representative, just aforesaid positive focus 140 by focus error signal and RF signal.

Because the Development Technology of CD-RW discsCD-RW and CD-ROM device is to present positive correlation, and the integration trend of all kinds of information products, therefore along with the significantly growth of numerous smooth stored prods with weed out the old and bring forth the new, the CD-ROM device with complex function that is used to read the video disc audiovisual materials is in the correct and quick interpretation of Storage Media kind, and the design of optical R/W signal control circuit and wafer also needs superior day by day.For example in order to read SACD CD-RW discsCD-RW data, it is a SACD sheet or a DVD double-layer tablet (DVD dual layer or DVD double layer) that CD-ROM device must correctly be differentiated the source video disc, in case can interpretation bright dipping disc kind be to belong to a SACD sheet, just laser light source is focused on the CD layer reads data to CD-ROM device then, and is unlikely to make a mistake.Therefore, develop a kind of mechanism to satisfy the aforesaid Storage Media kind demand of interpretation correctly and fast, and provide CD-ROM device one smoothly the Storage Media data read flow process, real in to need one of research and development problem of processing badly, just become the improved target of current industry utmost point need.

Because the defective that above-mentioned existing CD identification method exists, the inventor is based on being engaged in this type of product design manufacturing abundant for many years practical experience and professional knowledge, and the utilization of cooperation scientific principle, actively studied innovation, in the hope of founding a kind of new CD identification method, can improve general existing CD identification method, make it have more practicality.Through constantly research, design, and after studying repeatedly and improving, create the present invention who has practical value finally.

Summary of the invention

A fundamental purpose of the present invention, be to overcome the defective that existing CD identification method exists, a kind of double-layer CD sheet method of discrimination is provided, be to be used to differentiate in the optical read head moving period pair of lamina CD-RW discsCD-RW kind, its step is at first to detect to obtain one first focus error signal, wherein this first focus error signal comprises one first focus error signal peak value, one first focus error signal valley and one first threshold value, and this first focus error signal valley is in essence less than this first threshold value.Then, rise in the schedule time obtaining this first focus error signal, whether detecting second focus error signal greater than one second threshold value occurs, to obtain the corresponding second focus error signal peak value, uses this kind of differentiation double-layer CD sheet and belongs to a DVD double-layer CD sheet.If the second focus error signal peak value that there is no in during this greater than this second threshold value occurs, before just then back to optical read head moving period finishes at the fixed time during this period of time in the middle of, whether detecting has this second focus error signal peak value greater than one the 3rd threshold value to occur, and uses this kind of differentiation double-layer CD sheet and belongs to a SACD CD-RW discsCD-RW.Therefore, if in order to read the content of SACD CD-RW discsCD-RW, CD-ROM device can be by double-layer CD sheet method of discrimination of the present invention, correctly and fast differentiating this double-layer CD sheet kind in optical read head moving period is a SACD CD-RW discsCD-RW, a but not DVD double-layer tablet, then laser light source is focused on the CD layer correctly to read data, the Storage Media data reads flow process to carry out smoothly.

A syllabus of the present invention, be to overcome the defective that existing CD identification method exists, a kind of CD identification method is provided, be to be used to differentiate in the optical read head moving period CD-RW discsCD-RW kind, its step is at first to detect to obtain one first focus error signal, wherein this first focus error signal comprises one first focus error signal peak value, one first focus error signal valley and one first threshold value, and this first focus error signal valley is in essence less than this first threshold value.Then, rise in the schedule time obtaining this first focus error signal, whether detecting second focus error signal greater than one second threshold value occurs, to obtain the corresponding second focus error signal peak value, uses this kind of differentiation double-layer CD sheet and belongs to a DVD double-layer CD sheet.If the second focus error signal peak value that there is no in during this greater than this second threshold value occurs, before just then back to optical read head moving period finishes at the fixed time during this period of time in the middle of, whether detecting has this second focus error signal peak value greater than one the 3rd threshold value to occur, and uses this kind of differentiation double-layer CD sheet and belongs to a SACD CD-RW discsCD-RW.At last, as if the second focus error signal peak value that does not record all the time in this optical read head moving period greater than this 3rd threshold value, CD-ROM device just judges that this CD-RW discsCD-RW kind belongs to a single-layer sheet; On the other hand, if in this optical read head moving period, do not record first focus error signal of its first focus error signal valley all the time less than first threshold value, CD-ROM device just is judged to be does not put into CD-RW discsCD-RW, can send mistake and subsequent alerts information this moment, the relevant and correct running program with the indication user.Therefore, CD-ROM device can be by CD identification method of the present invention, correctly and fast determines kind under the CD-RW discsCD-RW of source in optical read head moving period, correctly reads data after the rail relative program carries out focusing on following then.

The present invention compared with prior art has tangible advantage and beneficial effect.By above technical scheme as can be known, technology contents of the present invention is as follows:

Double-layer CD sheet method of discrimination of the present invention and CD identification method, be according to this focus error signal peak value size and the kind of opportunity occur in an optical read head moving period with decision source CD-RW discsCD-RW, correctly read the CD-RW discsCD-RW inside information for pick-up head for optical disk player, therefore whether really put into CD-ROM device for read if can differentiate CD-RW discsCD-RW fast, and correctly the kind of interpretation source CD-RW discsCD-RW be belong to DVD double-layer tablet, SACD CD-RW discsCD-RW or single-layer sheet one of them, correctly read the CD-RW discsCD-RW content for CD-ROM device and optical read head to relevant position.

In sum, the CD identification method that the present invention is special, it has above-mentioned many advantages and practical value, and in class methods, do not see have similar design to publish or use and really genus innovation, no matter it is all having bigger improvement on method or on the function, have large improvement technically, and produced handy and practical effect, and more existing CD identification method has the multinomial effect of enhancement, thereby be suitable for practicality more, and have the extensive value of industry, really be a new and innovative, progressive, practical new design.

Above-mentioned explanation only is the general introduction of technical solution of the present invention, for can clearer understanding technological means of the present invention, and can be implemented according to the content of instructions, and for above-mentioned and other purposes, feature and advantage of the present invention can be become apparent, below especially exemplified by preferred embodiment, and conjunction with figs., be described in detail as follows.

Description of drawings

Figure 1A is the focus error signal value variation synoptic diagram for the method for astigmatism of foundation known techniques.

Figure 1B is the focus error signal value variation synoptic diagram for the cutter lot or luck by which people are brought together of foundation known techniques.

Fig. 2 is the flow chart of steps for the double-layer CD sheet method of discrimination of foundation a preferred embodiment of the present invention.

Fig. 3 A is the method for astigmatism focusing and OPTICAL SENSORS synoptic diagram for one preferred embodiment of foundation known techniques.

Fig. 3 B is the focusing of cutter lot or luck by which people are brought together and OPTICAL SENSORS synoptic diagram for one preferred embodiment of foundation known techniques.

Fig. 3 C is the right spot method focusing and OPTICAL SENSORS synoptic diagram for one preferred embodiment of foundation known techniques.

Fig. 4 is the flow chart of steps for the CD identification method of foundation a preferred embodiment of the present invention.

Fig. 5 is the optical read head moving period inner focusing error signal of foundation a preferred embodiment of the present invention and the synoptic diagram of threshold value waveform.

110,150: nearly burnt zone

120: positive burnt zone

130,170: burnt zone far away

140,160: positive focus

310: object lens

320: cylindrical lens

330,330a, 330b, 330c: four fens OPTICAL SENSORS

331,332,333,334,351,352,361,362,363: optical diode

340: knife plate

350: two minutes OPTICAL SENSORS

360: three minutes OPTICAL SENSORS

510: the optical read head motion track

511: optical read head position low spot

512: the high point in optical read head position

520: the first focus error signals

521: the first focus error signal peak values

522: the first focus error signal valleies

523: the first threshold values

530: the schedule time

540,560: the second focus error signals

541,561: the second focus error signal peak values

543: the second threshold values

563: the three threshold values

Embodiment

Reach technological means and the effect that predetermined goal of the invention is taked for further setting forth the present invention, below in conjunction with accompanying drawing and preferred embodiment, to its embodiment of CD identification method, method, step, feature and the effect thereof that foundation the present invention proposes, describe in detail as after.

From the above, the invention relates to according to the time of occurrence of focus error signal and size to differentiate the CD identification method of CD-RW discsCD-RW kind.See also shown in Figure 2ly, it is double-layer CD sheet method of discrimination of the present invention one preferred embodiment.In this embodiment, the flow process of this double-layer CD sheet method of discrimination comprises following steps: at first, at step S200 the position of one optical read head is moved from low to high, the omnidistance temporal summation that is spent is an optical read head moving period, then detect to obtain one first focus error signal FE 1 at step S220, wherein this first focus error signal FE 1 comprises one first focus error signal peak F E 1_Peak at least, one first focus error signal valley FE1_Bottom and one first threshold value FE 1_Thrl, and this first focus error signal valley FE1_Bottom is in essence less than this first threshold value FE 1_Thr_1.Obtaining in 1 one schedule time T0 of this first focus error signal FE detecting at step S240 then and whether occurring, so can differentiate this kind double-layer CD sheet and belong to a DVD double-layer CD sheet greater than the one second focus error signal peak F E 2_Peak of the one second focus error signal FE 2 of one second threshold value FE2_thr_2.If the second focus error signal peak F E2_Peak that there is no during this period greater than this second threshold value FE 2_thr_2 occurs, just then carry out step S260, before finishing to optical read head moving period behind the T0 at the fixed time during this period of time in the middle of, whether detecting has this second focus error signal peak F E 2_Peak greater than one the 3rd threshold value FE 3_thr_3 to occur, and so is that this kind of decidable double-layer CD sheet belongs to a SACD CD-RW discsCD-RW.

One carry at this, the purpose that focuses on is in order to the distance between monitoring CD-RW discsCD-RW and the object lens, to keep reading focal length, and in order to further specify flesh and blood and the constituted mode of the first focus error signal FE 1 and the second focus error signal FE 2 among the present invention, enumerate and narrate focus method commonly used and focus error signal value account form thereof at this, with as the aid illustration according to the focus error signal value of CD-RW discsCD-RW data reading method of the present invention, and those narrations also can be continued to use respectively in the preferred embodiment according to CD identification method of the present invention and double-layer CD sheet method of discrimination.

Fig. 3 A is the method for astigmatism focusing and OPTICAL SENSORS synoptic diagram for one preferred embodiment of foundation known techniques.Because method of astigmatism is to use object lens 310, one cylindrical lens 320 and one or four fens OPTICAL SENSORS 330, when changing, the distance of the object lens 310 of the reflection horizon of CD-RW discsCD-RW 300 and optical read head cause focal position not simultaneously, luminous point on this four fens OPTICAL SENSORS 330 presents difformity, and its focus error signal value can utilize formula F ES=(A+C)-(B+D) to try to achieve, and its RF signal then can utilize formula RF=A+B+C+D to try to achieve, wherein (diode is a diode to optical diode, below all be called diode) A331, B332, C333 will produce the unlike signal value because receiving different intensities of reflected light respectively with D334, for example regional 110 the time when being positioned at nearly Jiao shown in Figure 1A, because a little less than optical diode A331 and C333 are subjected to light, and optical diode B332 and D334 are subjected to light stronger, therefore result shown in four fens OPTICAL SENSORS 330a will produce the focus error signal of negative value.For example regional 120 the time again when being positioned at positive Jiao, because four optical diodes 331 to 334 are subjected to light intensity identical, make that resulting focus error signal is zero when correct focusing, result shown in four fens OPTICAL SENSORS 330b.In addition, regional 130 the time when being positioned at Jiao far away, optical diode A331 and C333 are subjected to light stronger, and a little less than optical diode B332 and D334 be subjected to light, result shown in four fens OPTICAL SENSORS 330c, therefore produce on the occasion of focus error signal.Then, focus servosystem will focus on action and result to adjust with this focus error signal as input.

Fig. 3 B is the focusing of cutter lot or luck by which people are brought together and OPTICAL SENSORS synoptic diagram for one preferred embodiment of foundation known techniques.Because the cutter lot or luck by which people are brought together is to use this object lens 310, this cylindrical lens 320, one knife plate 340 and one or two fens OPTICAL SENSORS 350 etc. focus on, its focus error signal value can utilize formula F ES=D1-D2 to try to achieve, and the optical diode D1 351 that wherein is positioned at this OPTICAL SENSORS 350 and D2 352 suffered light intensity when focusing on is identical, therefore focus error signal is zero, for example shown in the positive focus 160 of Figure 1B, and D2 352 is subjected to light intensity greater than D1 351 when near Jiao, therefore produce the focus error signal of negative value, for example shown in the near burnt zone 150 of Figure 1B, and D1 351 is subjected to light intensity greater than D2 352 when Jiao far away, therefore produce on the occasion of focus error signal, for example shown in the far away burnt zone 170 of Figure 1B.In addition, Fu Kefa is in response in cutter lot or luck by which people are brought together uppity shortcoming when closely burnt, therefore change with prism replacement cutter edge, and with four optical diode D1, D2, D3 and D4 sensor light intensity, its principle is similar to the cutter lot or luck by which people are brought together, does not therefore repeat them here.On the other hand, the OPTICAL SENSORS structure of critical angle method also is similar to the cutter lot or luck by which people are brought together, this critical angle method is to use a reflecting prism, enter the angle of this reflecting prism with the detecting focus error signal by adjusting light, wherein if light is parallelly can produce total reflection when entering prism, make two optical diodes that are positioned at OPTICAL SENSORS receive identical light intensity, so focus error signal is zero; Far away burnt and near when burnt, because formed convergence of focusing error or diverging light will make light produce the part refraction, therefore the difference that produces of the light intensity that receives at two optical diodes can be used as focus error signal.

Fig. 3 C is the right spot method focusing and OPTICAL SENSORS synoptic diagram for one preferred embodiment of foundation known techniques.Because right spot method is to use one or three fens OPTICAL SENSORS 360, and this OPTICAL SENSORS 360 has three optical diode A361, B362 and C363, and its focus error signal value can utilize formula F ES=(A+C)-B to try to achieve.When being positioned at positive Jiao, the light intensity summation of optical diode A361 and C363 equals the value of optical diode B362, makes that therefore focus error signal is zero; Near when burnt when being positioned at, with produce on the occasion of focus error signal, and be positioned at far when burnt, will produce the focus error signal of negative value.

See also Fig. 4, it is CD identification method one preferred embodiment of the present invention.In this embodiment, the flow process of this CD identification method comprises following steps: at first, at step S400 the position of one optical read head is moved from low to high, the omnidistance temporal summation that is spent is an optical read head moving period, then detect to obtain one first focus error signal FE 1 at step S420, wherein this first focus error signal FE 1 comprises one first focus error signal peak F E 1_Peak at least, one first focus error signal valley FE 1_Bottom and one first threshold value FE 1_Thr1, and this first focus error signal valley FE 1_Bottom is in essence less than this first threshold value FE 1_Thr_1.One carry at this, if in this optical read head moving period, do not record the first focus error signal FE 1 of its first focus error signal valley FE 1_Bottom all the time greater than the first threshold value FE 1_Thr_1, then can be judged to be by CD-ROM device and not put into CD-RW discsCD-RW at step S490, and send mistake and subsequent alerts information, relevant and correct running program with the indication user.

Then, after completing steps S420, carry out step S440, whether detecting occurs greater than the one second focus error signal peak F E 2_Peak of the one second focus error signal FE 2 of one second threshold value FE 2_thr_2 in obtaining 1 one schedule time T0 of this first focus error signal FE, can differentiate this kind double-layer CD sheet and belongs to a DVD double-layer CD sheet if occur.If the second focus error signal peak F E 2_Peak that there is no during this period greater than this second threshold value FE 2_thr_2 occurs, just then carry out step S460, before finishing to optical read head moving period behind the T0 at the fixed time during this period of time in the middle of, whether detecting has this second focus error signal peak F E 2_Peak greater than one the 3rd threshold value FE 3_thr_3 to occur, if occur is that this kind of decidable double-layer CD sheet belongs to a SACD CD-RW discsCD-RW, at last, if do not record the second focus error signal peak F E 2_Peak greater than this 3rd threshold value FE 3_thr_3 all the time in this optical read head moving period, then CD-ROM device just judges that at step S480 this CD-RW discsCD-RW kind belongs to a single-layer sheet.Finish in case the CD-RW discsCD-RW kind is judged, CD-ROM device just can be carried out the correct data fetch program according to the attribute of this CD-RW discsCD-RW.

In order to further specify the present invention and relevant preferred embodiment, see also Fig. 5, it is the synoptic diagram for optical read head moving period's inner focusing error signal of the present invention and threshold value waveform.The oblique line that extends by lower-left to upper right side represent optical read head in optical read/write head moving period by the formed track 510 in low spot 511 lofty perches 512 shift positions, in this one-period, CD identification method one preferred embodiment according to Fig. 4, when the optical read head position when step S400 is moved by low spot 511 lofty perches 512, record one first focus error signal FE 1 520 at step S420, its waveform as previously mentioned, it is a sigmoid curve, wherein this first focus error signal FE 1 520 comprises one first focus error signal peak F E 1_Peak 521 at least, one first focus error signal valley FE1_Bottom 522 and one first threshold value FE 1_T,hr1 523, and this first focus error signal valley FE 1_Bottom 522 amplitudes are less than this first threshold value FE 1,_Th,r_1 523.Then, at step S440, whether detecting occurs greater than the one second focus error signal peak F E 2_Peak 541 of the one second focus error signal FE 2 540 (its waveform also is a sigmoid curve) of one second threshold value FE 2,_th,r_2 543 in obtaining 1 one schedule time T0 530 of this first focus error signal FE, can differentiate this kind double-layer CD sheet and belongs to a DVD double-layer CD sheet if occur.If the second focus error signal peak F E 2_Peak541 that there is no during this period greater than this second threshold value FE 2,_th,r_2 543 occurs, just then carry out step S460, height points 512 before T0 530 back to optical read head moving periods finish at the fixed time during this period of time in the middle of, whether detecting has the second focus error signal peak F E2_Peak 561 greater than the one second focus error signal FE 2 560 of one the 3rd threshold value FE3_thr_3 563 to occur, so be that this kind of decidable double-layer CD sheet belongs to a SACD CD-RW discsCD-RW, at last, if do not record the second focus error signal peak F E 2_Peak 560 greater than this 3rd threshold value FE 3_thr_3563 all the time in this optical read head moving period, then CD-ROM device just judges that at step S480 this CD-RW discsCD-RW kind belongs to a single-layer sheet.Finish in case the CD-RW discsCD-RW kind is judged, CD-ROM device just can be carried out the correct data fetch program according to the attribute of this CD-RW discsCD-RW.

The above, it only is preferred embodiment of the present invention, be not that the present invention is done any pro forma restriction, though the present invention discloses as above with preferred embodiment, yet be not in order to limit the present invention, any those skilled in the art, in not breaking away from the technical solution of the present invention scope, when the method that can utilize above-mentioned announcement and technology contents are made a little change or be modified to the equivalent embodiment of equivalent variations, in every case be the content that does not break away from technical solution of the present invention, according to technical spirit of the present invention to any simple modification that above embodiment did, equivalent variations and modification all still belong in the scope of technical solution of the present invention.

Claims

1. a double-layer CD sheet method of discrimination is in order to differentiation pair of lamina CD-RW discsCD-RW kind in an optical read head moving period, it is characterized in that it comprises:

Detecting is to obtain one first focus error signal, wherein this first focus error signal comprises one first focus error signal peak value, one first focus error signal valley and one first threshold value, and this first focus error signal valley is less than this first threshold value;

Play in the schedule time one second focus error signal of its peak value of detecting greater than one second threshold value obtaining this first focus error signal, differentiating this double-layer CD sheet is a DVD double-layer CD sheet; And

After this schedule time to its peak value of detecting is greater than this second focus error signal of one the 3rd threshold value between this optical read head moving period, differentiating this double-layer CD sheet is a SACD CD-RW discsCD-RW.

2. a CD identification method is in order to differentiation one CD-RW discsCD-RW kind in an optical read head moving period, it is characterized in that it comprises:

Detecting is to obtain one first focus error signal, wherein this first focus error signal comprises one first focus error signal peak value, one first focus error signal valley and one first threshold value, and this first focus error signal valley is in essence less than this first threshold value;

Play in the schedule time one second focus error signal of its peak value of detecting greater than one second threshold value obtaining this first focus error signal, differentiating this CD-RW discsCD-RW kind is a DVD double-layer CD sheet; And

After this schedule time to its peak value of detecting is greater than this second focus error signal of one the 3rd threshold value between this optical read head moving period, differentiating this CD-RW discsCD-RW kind is a SACD CD-RW discsCD-RW.

3. CD identification method according to claim 2 is characterized in that wherein this CD-RW discsCD-RW kind is a single-layer sheet if do not record its peak value this second focus error signal greater than the 3rd threshold value in this optical read head moving period.