CN1227660C - Optical medium identification method - Google Patents
Optical medium identification method Download PDFInfo
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- CN1227660C CN1227660C CN 02158495 CN02158495A CN1227660C CN 1227660 C CN1227660 C CN 1227660C CN 02158495 CN02158495 CN 02158495 CN 02158495 A CN02158495 A CN 02158495A CN 1227660 C CN1227660 C CN 1227660C
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- optical medium
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- determination methods
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Abstract
The present invention relates to an optical medium determination method which can effectively distinguish a DVD disk and a CD disk in order to be favorable to an optical drive to read. The method makes an optical pickup reciprocate between two limit positions, which makes a focused beam pass through a data layer of the optical disk twice; then the time difference or the range difference of two reflection peaks, exceeding the threshold value of a reflection quantity is measured. Thereby, the disk type can be judged according to the result. Because the reflection peak of a transparent layer of the disk does not need to be detected, the erroneous judgment opportunity is reduced, which can effectively promote the reading efficiency of the optical drive.
Description
Technical field
The present invention relates to a kind of optical medium determination methods, especially a kind ofly can effectively distinguish DVD disc and CD disc, to help the method that CD-ROM drive reads.
Background technology
Therefore media for storing optical information is subjected to gazing at of industry and consumer because there is capacity to reach the untouchable advantage that reads greatly always.From the read-only compact video disc (LD) that occurs the earliest, music CD (CD), optical data disk (CD-ROM) and erasable CD (CD-RW) etc., because physical arrangement, specification and technology limitation, so capacity there is no very big breakthrough.Come out up to Video CD (DVD), owing to have the light source of less gauge, minimum pit hole length and use shorter wavelength, so the more known optical data disk of capacity promotes more than seven times.
The specification formulated of Video CD (DVD) can roughly be sorted out as follows so far.
1.BOOKA:DVD-ROM the DVD-ROM machine must be compatible forward with known optical data disk (CD-ROM).
2.BOOK B:DVD-Video, the DVD-Video machine must be compatible forward with known videodisc (VideoCD).
3.BOOK C:DVD-Audio, the DVD-Audio machine must be compatible forward with known music CD (CD).
4.BOOK D:DVD-R, the DVD-R machine must be compatible forward with the CD (CD-RW) of known read-write.
5.BOOK E:DVD-RAM uses phase change optical disk.
In aforesaid four kinds of Video CDs, since must with known optical data disk (CD-ROM), videodisc (video CD), music CD (CD), and erasable CD (CD-RW) compatible forward, therefore general DVD-ROM machine also wants to read the CD of CD-ROM form.Right in the DVD disc has different physical arrangements and reads mode with the CD disc, therefore must to differentiate disc kind fast be Video CD (being called for short the DVD disc) and general disc (being called for short the CD disc) to digital laser video disk machine (DVD drive), to take the suitable mechanism that reads.
As shown in Figure 1, read the synoptic diagram of a disc 20 for optical head and associated component thereof in the known CD-ROM drive.This optical head comprises a laser diode 10, it launches the laser beam of a specific wavelength, this light beam through one the polarization optical splitter 11 after, by a collimator 12 with its converge parallel beam, parallel beam will become Circular Polarisation for the linearly polarized light beam originally through a quarter wave plate 13.The Circular Polarisation light beam forms a luminous point SP on disc after via the focusing of object lens 14.One drive circuit 30 drives an actuator 32, controlling these object lens 14 by moving along the optical axis fore-and-aft direction, and changes luminous point SP position, and luminous point SP can be focused on the data Layer of disc.Luminous point SP oppositely via behind object lens 14, the quarter wave plate 13, is become linear polarization by original Circular Polarisation by the reflected light of disc data layer, arrives polarization optical splitter 11 via collimator 12 again.This moment, folded light beam was because linear polarization direction and original light beam polarised direction were vertical, therefore can be reflected to behind the condenser lens 15 again by a device for testing light 16 receptions.
Referring to Fig. 2 A and Fig. 2 B, be the synoptic diagram of known discs determination methods.Because the distance on DVD disc data layer 22 and hyaline layer border is about the distance on 0.6mm, CD disc data layer 22 and hyaline layer border and is about 1.2mm (the disc gross thickness is 1.2mm, data Layer is very near the printed layers right with the hyaline layer borderline phase), therefore in known technology, be that light beam is judged disc kind by the hyaline layer edge reflection and by the range difference that data Layer reflects when measuring flying optical head.More specifically, as shown in Figure 3, trace reflection spike (peak) can be caused to luminous point in the hyaline layer border, and data Layer can cause bigger reflection spike to luminous point.For the DVD disc, the distance of these two reflection spikes is about 0.6mm; And for the CD disc, the distance of these two reflection spikes is about 1.2mm.By differentiating range difference or the mistiming between the spike, know that promptly disc is DVD disc or CD disc.Yet because trace reflection only can be caused to luminous point in the hyaline layer border, therefore be difficult for differentiating the position of hyaline layer, related can't the judgment data layer and the distance on hyaline layer border, so cause erroneous judgement.
Summary of the invention
The object of the present invention is to provide a kind of optical medium determination methods, this method can effectively be distinguished DVD disc and CD disc, reads to help CD-ROM drive.
Purpose of the present invention can realize by following measure:
A kind of optical medium determination methods is to use in an optical medium reading device, and the removable optical head of this optical medium reading device is between a primary importance and a second place, and this method comprises the following step:
A. move to this second place at this optical head by this primary importance and also retract once more in the process of this primary importance, calculate this optical head by a T.T. that obtains on the optical medium to be spent between high twice volume reflection or the corresponding acquisition total distance that high twice this optical head of volume reflection is moved; And
B. according to this T.T. or total distance, judge the type of this optical medium.
Wherein, this primary importance and this second place are between the lowest positions and position, the top that this optical head can arrive, and also retract once more in the process of this primary importance when this optical head moves to this second place by this primary importance, this optical head focuses on the luminous point that forms and needs twice through the data Layer on this optical medium.
This method also comprise with obtain twice high volume reflection face T.T. and one in limited time between comparison, to judge the type of this optical medium.
This method also comprise with obtain twice high volume reflection deduct T.T. this optical head by primary importance move to that the second place obtains the first time high volume reflection mistiming of time face the comparison of limit time value with at least one, to judge this optical medium type.
Facing distinguishable this CD of limit time value comparative result according to described mistiming and this is DVD CD or CD CD.
This method also comprises faces range line from relatively, to judge the type of this optical medium with the total distance and that obtains twice high volume reflection.
This method also comprise total distance that will obtain twice high volume reflection deduct this optical head by primary importance move to that the second place obtains the first time high volume reflection the range difference of distance face the comparison of limit distance value with at least one, to judge this optical medium type.
Institute took place when described high twice volume reflection was a laser beam that this optical head launches and strides across a data Layer of this optical medium.
Described optical medium is a CD, and this optical medium reading device is a CD-ROM drive.
Described primary importance is the position, the top that this optical head can arrive, and the second place is the lowest positions that this optical head can arrive.
Described primary importance is the lowest positions that this optical head can arrive, and the second place is the position, the top that this optical head can arrive.
The present invention has following advantage compared to existing technology:
The invention provides a kind of optical medium determination methods, the method is optical read head to be come and gone move between two extreme positions, make focused beam to pass through the data of optical disk layer twice, measure T.T. or mistiming or the total distance or the range difference of two reflection spikes that surpass a volume reflection threshold value again, promptly can this result judge disc kind; Owing to must not detect the reflection spike of disc hyaline layer, therefore reduce the erroneous judgement chance, can effectively promote the CD-ROM drive reading efficiency.
Description of drawings
Fig. 1 is the system schematic of known CD-ROM drive reading signal;
Fig. 2 A and Fig. 2 B illustrate the synoptic diagram of known disc identifying method;
Fig. 3 illustrates the reflection parameters measurement result synoptic diagram of known disc identifying method;
Fig. 4 A and Fig. 4 B are luminous point shift motion synoptic diagram of the present invention;
Fig. 5 is the synoptic diagram of reflection parameters measurement result of the present invention; And
Fig. 6 is a process flow diagram of the present invention.
Concrete embodiment
The invention provides a kind of optical medium determination methods, can effectively distinguish DVD disc and CD disc, referring to Fig. 1,5 and Fig. 6, flow process of the present invention is as follows:
Step 100 moves to the lowest positions H that an optical head can arrive with the focalizer of optical head;
Step 102 is lighted a laser;
Step 104 moves to position, the top U that an optical head can arrive with the focalizer of optical head, and continues the laser beam volume reflection of record when mobile, and record exceeds first spike time of origin t1 or the t3 of a reflection threshold value (seeing that dotted line partly);
Step 106 moves to the lowest positions H that an optical head can arrive again with the focalizer of optical head, and continues the laser beam volume reflection of record when mobile, and record exceeds second spike time of origin t2 or the t4 of a reflection threshold value;
Step 108 is calculated the mistiming (Δ t=t2-t1 or Δ t=t4-t3) of the first spike time of origin t1 and the second spike time of origin t2
Step 110 is by a reduced time difference Δ t and a time threshold value, and disc is DVD disc or CD disc as can be known.
Among flow process of the present invention, focalizer with optical head moves to the lowest positions H that an optical head can arrive earlier, focalizer with optical head moves to position, the top U that an optical head can arrive again, last again the focalizer of optical head is moved to the lowest positions H that an optical head can arrive again.Therefore shown in Fig. 4 A, 4B, luminous point SP can move to a lower position H ' earlier, moves on to a upper limit position U ' again, moves to this lower position H ' at last again, in this process, and respectively can be through DVD data of optical disk layer 22 and CD data of optical disk layer 22 twice.CD data of optical disk layer 22 as shown in Figure 5,, therefore has bigger mistiming Δ t=t2-t1, owing in darker position, therefore can laterly run into luminous point SP, and less mistiming Δ t=t4-t3 is arranged because luminous point SP can run into DVD data of optical disk layer 22 earlier.As mentioned above, can be poor, and judge disc kind by judgement time, as the mistiming greater than this threshold value, be expressed as the DVD disc, otherwise be the CD disc.
More specifically, in the present invention, except the focalizer of optical head being moved on to position, the top U that optical head can arrive by the lowest positions H that originally optical head can arrive, retract again outside the lowest positions H that optical head can arrive, position, the top U that the focalizer original position of optical head can also can arrive for optical head, and have and opposite stroke shown in Figure 4.Moreover among the present invention, the stroke of the focalizer of optical head also need not be between the lowest positions H that position, the top U that optical head can arrive and optical head can arrive, as long as can be through data of optical disk layer 22 twice among its stroke.
Moreover the total distance that focalizer moved that can also calculate optical head between two reflection spikes in the present invention decides.That is the focalizer of supposing optical head is to move to position, the top U that an optical head can arrive by the lowest positions H that an optical head can arrive to move back to the lowest positions H that optical head can arrive again.Total distance that the focalizer of optical head moves between two reflection spikes when inserting the DVD disc total distance that the focalizer of optical head moves between two reflection spikes when inserting the CD disc that is bound to.Therefore, can set one and face range line obtains disc from the total distance that focalizer moved by the contrast optical head kind.
The total distance that focalizer moved that can also calculate in addition optical head between two reflection spikes in the present invention deduct this optical head by primary importance move to that the second place obtains the first time high volume reflection the range difference of distance limit the distance value comparison with at least one facing, decide again to judge this optical medium type.
Above-mentioned only is embodiments of the invention, allly be skillful in this skill person when can doing other all improvement according to above-mentioned explanation, as the reflection spike of judging disc is except being caused by reflectance varies, can also comprise by magnetic and change or the resulting reflection spike of phase change, and these change and still belong in invention spirit of the present invention and the following claim that is defined.
Claims (10)
1, a kind of optical medium determination methods is to use in an optical medium reading device, and the removable optical head of this optical medium reading device is between a primary importance and a second place, and this method comprises the following step:
A. move to this second place at this optical head by this primary importance and also retract once more in the process of this primary importance, calculate this optical head by a T.T. that obtains on the optical medium to be spent between high twice volume reflection or the corresponding acquisition total distance that high twice this optical head of volume reflection is moved; And
B. according to this T.T. or total distance, judge the type of this optical medium.
Wherein, this primary importance and this second place are between the lowest positions and position, the top that this optical head can arrive, and also retract once more in the process of this primary importance when this optical head moves to this second place by this primary importance, this optical head focuses on the luminous point that forms and needs twice through the data Layer on this optical medium.
2, optical medium determination methods as claimed in claim 1, it is characterized in that this method also comprise with obtain twice high volume reflection face T.T. and one in limited time between comparison, to judge the type of this optical medium.
3, optical medium determination methods as claimed in claim 1, it is characterized in that this method also comprise with obtain twice high volume reflection deduct T.T. this optical head by primary importance move to that the second place obtains the first time high volume reflection mistiming of time face the comparison of limit time value with at least one, to judge this optical medium type.
4, optical medium determination methods as claimed in claim 3 is characterized in that facing distinguishable this CD of limit time value comparative result according to described mistiming and this is DVD CD or CD CD.
5, optical medium determination methods as claimed in claim 1, it is characterized in that this method also comprises faces range line from relatively, to judge the type of this optical medium with the total distance and that obtains twice high volume reflection.
6, optical medium determination methods as claimed in claim 1, it is characterized in that this method also comprise total distance that will obtain twice high volume reflection deduct this optical head by primary importance move to that the second place obtains the first time high volume reflection the range difference of distance face the comparison of limit distance value with at least one, to judge this optical medium type.
7, optical medium determination methods as claimed in claim 1, institute takes place when it is characterized in that described high twice volume reflection is a laser beam that this optical head launches and strides across the data Layer of this optical medium.
8, optical medium determination methods as claimed in claim 1 is characterized in that described optical medium is a CD, and this optical medium reading device is a CD-ROM drive.
9, optical medium determination methods as claimed in claim 1 is characterized in that the position, the top that described primary importance can arrive for this optical head, and the second place is the lowest positions that this optical head can arrive.
10, optical medium determination methods as claimed in claim 1 is characterized in that the lowest positions that described primary importance can arrive for this optical head, and the second place is the position, the top that this optical head can arrive.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 02158495 CN1227660C (en) | 2002-12-25 | 2002-12-25 | Optical medium identification method |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 02158495 CN1227660C (en) | 2002-12-25 | 2002-12-25 | Optical medium identification method |
Publications (2)
| Publication Number | Publication Date |
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| CN1510676A CN1510676A (en) | 2004-07-07 |
| CN1227660C true CN1227660C (en) | 2005-11-16 |
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| CN 02158495 Expired - Fee Related CN1227660C (en) | 2002-12-25 | 2002-12-25 | Optical medium identification method |
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Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP4367351B2 (en) * | 2005-02-08 | 2009-11-18 | 船井電機株式会社 | Optical disk device |
| CN101471111B (en) * | 2007-12-28 | 2011-05-11 | 广明光电股份有限公司 | Disk identifying method |
| CN101661764B (en) * | 2009-09-14 | 2011-11-02 | 凌阳科技股份有限公司 | Distinguishing method and distinguishing device of optical discs |
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| Publication number | Publication date |
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| CN1510676A (en) | 2004-07-07 |
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Granted publication date: 20051116 Termination date: 20100125 |