CN1581307A - System and method for discriminating optical storage medium recording area - Google Patents

Abstract

The invention provides an optical determination system and method thereof, which are used for determining whether a reflected light beam is reflected from a plurality of header areas of an optical storage medium. The optical discrimination system comprises a light beam detection module and a signal detection module. The method generates a first header signal when a reflected light beam is reflected from a first recording position of the header area. When the reflected light beam is reflected by a second recording position of the header area, a second header signal is generated. When the reflected beam has an address information, an address mark signal is generated. When the first header signal and the second header signal are received successively and the address mark signal is received during the period, it is determined that the reflected light beam is reflected from one of the headers.

Description

System and method for identifying recording area of optical storage medium

field of invention

The present invention relates to an optical discrimination system and its method, in particular to an optical discrimination system and method for discriminating the title area of an optical storage medium applied in an optical read-write device.

Background of the invention

See Figure 1. FIG. 1 is a schematic diagram of a track 10 of a conventional optical disc. A conventional optical disc has a plurality of tracks 10 . A plurality of sectors 14 (sectors) are distinguished on the tracks 10 , and each sector 14 is composed of a header area 16 and a recording area 18 . In addition, a plurality of recording pits 11, 12, 13 (pit) are distributed on the track 10. The recording pits 11 and 12 of the header area 16 are respectively arranged along the upper and lower sides of the track 10 and are used for recording the address information of the sector 14 . The recording pit 13 of the recording area 18 is located in the middle of the track for recording data content.

In the existing optical disc reading and writing device, correctly identifying the header area will reduce errors when the optical reading and writing device reads and writes data. The existing technology is to use the header indication signal (header indication signal) generated by extracting low pass filtered RFsubtraction (RFSUB) signal or phase difference detection (differential phase detection, DPD) signal to assist in identifying the header area , so that the operation of the servo control (servo control) and pre-amplification circuit (RF circuit) of the optical read-write device is more reliable.

Please refer to FIG. 1 and FIG. 2 . FIG. 2 is a circuit for generating a title indication signal of a conventional optical disc reading and writing device.

In the prior art, light beams are irradiated to the middle part of the track 10 to detect the distribution of recording pits, so as to obtain four kinds of signals A, B, C and D respectively. Signals A, B, C and D respectively indicate the pothole distribution status of each track at the four positions A, B, C and D in FIG. 1 .

Due to the difference in the distribution of the recording pits, the strengths of the signals A, B, C and D are also different. Next, the signals A, B, C and D enter adder/subtractor 20 (FIG. 2). The adder/subtractor 20 performs the calculation of E=(A+D)-(B+C). Then the E value enters the high threshold comparator 24 and the low threshold comparator 26 respectively after passing through the low pass filter 22 .

When the light beam passes through the upper row of recording pits 11 in the header area 16, because there are no recording pits below the track, the A and D signals are greater than the B and C signals, so the E value is greater than 0. The value of E passes through the high threshold comparator 24 to obtain the header indicating signal CP1. Since the value of E after passing through the low threshold comparator 26 is less than 0, the header indication signal CP2 will not be generated when the light beam passes through the upper row of recording pits 11 in the header area 16 in FIG. 1 . Conversely, when the light beam passes through the lower row of recording pits 12 in the header area 16, because there is no recording pit above the track, the B and C signals are greater than the A and D signals, so the E value is less than 0. The value of E passes through the low threshold comparator 26 to obtain the title indicating signal CP2. Since the value of E after passing through the high threshold comparator 24 is less than 0, the header indication signal CP1 will not be generated when the light beam passes through the lower recording pit 12 of the header area 16 in FIG. 1 .

US Patent Application No. 2002/0039331 directly uses whether there are header indication signals CP1 and CP2 to identify whether the header area 16 is being read. When the title indication signals CP1 and CP2 are received successively, the area is regarded as the title area 16 .

The prior art only uses the title indication signal CP1 or CP2 as a signal for identifying the title area. However,

During the process of reading the optical disc by the optical reading device, it is easy for the light beam to deviate from the center of the track, so the title indication signal CP1 or CP2 often appears in the non-title area from time to time. Therefore, the prior art often cannot achieve the function of correctly identifying the title area, resulting in identification errors. This identification error will further cause errors when the optical read-write device reads and writes the optical disc. Therefore, there is a need for a method and system capable of correctly identifying the header area, so as to reduce errors when an optical read/write device reads and writes an optical disc, thereby improving the operating efficiency of the optical read/write device.

Summary of the invention

An object of the present invention is to provide an optical discrimination system and its method, which can solve the problems of the prior art.

Another object of the present invention is to provide an optical judging system and method thereof, which can correctly judge whether a reflected light beam is reflected from a plurality of headers on an optical storage medium.

In one embodiment, the optical judging system of the present invention is used to judge whether a reflected light beam is reflected from a plurality of headers on an optical storage medium. The optical discrimination system includes a light beam detection module and a signal detection module.

When the reflected light beam is reflected by a first recording position of the header area, a first header signal is generated. When the reflected light beam is reflected by a second recording position of the header area, a second header signal is generated. When the reflected light beam has an address information in it, an address mark signal is generated. When the first title signal and the second title signal are successively received and the address mark signal is received during this period, it is judged that the reflected light beam is reflected from one of the title areas.

The present invention utilizes the first title signal, the second title signal and the address mark signal simultaneously to identify the title area, which can reduce the reading error caused by the wrong first title signal and the second title signal, resulting in wrong identification of the title area. The present invention further shields the erroneous first title signal and the second title signal by generating the shielding signal, thereby achieving the purpose of reducing interference.

The advantages and spirit of the present invention can be further understood through the following detailed description of the invention and the accompanying drawings.

Description of drawings:

FIG. 1 is a schematic diagram of a track of an existing optical disc.

FIG. 2 is a circuit for generating a title indication signal of an existing optical disc reading and writing device.

FIG. 3 is a functional block diagram of the optical discrimination system of the present invention.

FIG. 4 is a schematic diagram of signal generation and several discrimination embodiments in the optical discrimination system of FIG. 3 .

FIG. 5 is a flow chart of the steps of the optical judgment method in the third embodiment shown in FIG. 4 .

Drawing logo:

50: Optical discrimination system 52: Beam detection module

54: Signal detection module 56: The first logical operation unit

58: second logical operation unit 60: counter

CP1: First title signal CP2: Second title signal

IS initial state MS: masked state

MP: masked interval

preferred embodiment

The invention provides an optical judging system for judging whether a reflected light beam is reflected from a title area on an optical storage medium. The reflected light beam is emitted by an optical read-write device and reflected by the optical storage medium. The optical storage medium is a known optical disc, such as DVD-RAM. The optical read-write device can be a known optical drive or optical disc recorder.

Please refer to FIG. 3 , which is a functional block diagram of the optical discrimination system 50 of the present invention. The reflected beam 51 is reflected from the track 10 of the optical storage medium shown in FIG. 1 . The header area on the optical storage medium is illustrated with the header area 16 of FIG. 1 . Each header area 16 includes a first recording location and a second recording location for recording a location information. The first recording position is the upper row of recording pits 11 in the header area 16 in FIG. 1 . The second recording position is the lower recording pit 12 of the header area 16 in FIG. 1 . According to the DVD-RAM specification, the address information can be generated for the variable frequency oscillator field (Variable Frequency Oscillator Field), address mark field (Address Mark Field), physical ID field (Physical ID Field) information in the title area or other reference information signal of.

The optical discrimination system 50 includes a beam detection module 52 and a signal detection module 54 . The light beam detection module 52 is used to receive the reflected light beam 51 . When the reflected beam 51 is reflected by the first recording position, the beam detection module 52 generates a first header signal CP1. When the reflected beam 51 is reflected by the second recording position, the beam detection module 52 generates a second header signal CP2. When the reflected beam 51 has the address information, the beam detection module 52 generates an address mark signal.

The signal detection module 54 is used to receive the first header signal CP1, the second header signal CP2 and the address mark signal. The signal detection module 54 has an initial state IS and a mask state MS. What state the signal detection module 54 should be in is controlled by the signal detection module 54 itself. When in the initial state IS, the signal detection module 54 receives all the first header signal CP1 and the second header signal CP2. When in the mask state MS, the signal detection module 54 generates a periodic mask signal to mask the first header signal CP1 and the second header signal CP2 received in the non-header area.

See Figure 4. FIG. 4 is a schematic diagram of signal generation and several discrimination embodiments in the optical discrimination system 50 of FIG. 3 . Since there are multiple sections on the optical storage medium, and each section includes a header area 16 and a recording area 18, the light beam detection module 52 will periodically send out the first title when reading each header area. The signal CP1 and the second title signal CP2. However, when the optical read/write device reads the optical storage medium, the problem that the laser beam deviates from the center of the track often occurs, so sometimes the first header signal CP1 and the second header signal CP2 are still sent out at the recording area 18 . At this time, the first title signal CP1 and the second title signal CP2 are the wrong first title signal CP1' and the second title signal CP2' in FIG. 4 .

When the optical drive starts to read the optical storage medium, the signal detection module 54 is preset in the initial state IS. When the signal detection module 54 receives the first header signal CP1 and the second header signal CP2 successively, and receives the address mark signal during this period, it will determine that the reflected light beam 51 is reflected from one of these header areas. When the signal detection module 54 determines that the reflected light beam 51 is reflected from the header area, it switches from the initial state IS to the shielded state MS. When the signal detection module 54 is in the initial state IS, it must receive the first title signal CP1 and the second title signal CP2 successively, and only when it receives the address mark signal during this period, can it be determined that the reflected light beam is reflected from the title area. When the signal detection module 54 is in the masking state MS, it will periodically generate a masking signal to mask the received first header signal CP1 and second header signal CP2 . Therefore, as long as the unshielded first header signal CP1 and the second header signal CP2 are received, it can be determined that the reflected light beam is reflected from the header area 16 . The signal length of the masking signal can be set as the distance 14 between adjacent header areas. The distance 14 is equal to the length of each non-header area 16 and also equal to the length of the recording area 18 . In FIG. 4 , the time at which the signal detection module 54 starts switching states and sends out the masking signal is represented by the time axis T. As shown in FIG.

As shown in FIG. 3 , the signal detection module 54 further includes a first logic operation unit 56 and a second logic operation unit 58 . The first logical operation unit 56 is used for receiving the first title signal CP1 and the masking signal. The second logical operation unit 58 is used for receiving the second title signal CP2 and the masking signal. When the first logic operation unit 56 receives the first header signal CP1' and the masking signal simultaneously, the masking signal will mask the first header signal CP1'. Similarly, when the second logic operation unit 58 receives the second title signal CP2' and the shielding signal simultaneously, it will shield the second title signal CP2'.

The present invention confirms whether the light beam is located in the header area 16 by the address mark signal, and further sends out the first header signal CP1' and the second header signal CP2' which mask errors by the masking signal, which can reduce the time for the optical read-write device to read the optical storage medium. chance of error.

The optical discrimination system 50 may further include a counter 60 (counter). When the signal detection module 54 is in the masking state MS, the counter 60 is used to calculate the length of a masking interval MP that sends out the masking signal. According to a specific embodiment of the present invention, the counter 60 starts counting from zero, starts the masking interval MP when the counter 60 counts to a first specific value, and ends the masking interval MP after counting to a second specific value. When the signal detection module 54 receives an unmasked CP1 or CP2 signal, the count of the counter 60 will return to zero. The interval between the first specific value and the second specific value may be the length of a recording area 18 in the optical storage medium.

An example is given here to illustrate the operation of the counter 60 . The existing counter 60 measures time in units of bytes. When the counter 60 receives the first header signal CP1 and the second header signal CP2, it starts counting from zero. When the counter 60 counts to the eighth byte of the recording area 18, the signal detection module 54 can send out the masking signal, and the masking interval MP starts. One recording area 18 of a conventional DVDRAM contains 2567 bytes. Then, when the counter 60 counts to the 2,500th byte, the signal detection module 54 can end the masking interval MP, that is, stop sending the masking signal.

When the counter 60 receives the unmasked first header signal CP1 and the second header signal CP2 again, the above steps are repeated.

In the following, the signals generated by each item shown in FIG. 4 will be used to illustrate the optical discrimination method of the present invention with three embodiments. The main difference among the various embodiments lies in the setting of conditions for the signal detection module to enter and leave the shielding state.

According to one of the embodiments shown in FIG. 4 , the lengths of the header area 16 and the recording area 18 are fixed on the optical storage medium. Therefore, when the first header area 16 is confirmed by the first header signal CP1 , the second header signal CP2 and the address mark signal, the signal detection module enters the masking state MS. Regardless of whether the subsequent optical discrimination system 50 receives the address mark signal again, the signal detection module remains in the shielded state MS. The counter 60 starts counting from zero after the first header field 16 is confirmed. Whenever the counter 60 counts a certain number of bytes, it indicates that the next header field 16 is approaching, and the mask signal must be cleared. Therefore, the signal detection module 54 periodically sends out the masking signal at the non-title area 16 according to the counting result of the counter 60 . The first logic operation unit 56 and the second logic operation unit 58 can mask the errors CP1' and CP2' issued at the recording area 18 according to the masking signal. The timing sequence of the masking signal generated by the signal detection module 54 is shown in masking signal 1 in FIG. 4 .

However, when the counting clock of the counter 60 is unstable, or an error occurs in the recognition of the first title area 16, the practice of the first embodiment in FIG. 4 will jointly affect subsequent identification of all title areas. The second embodiment in FIG. 4 can avoid the problem of the first embodiment in FIG. 4 . According to the second embodiment in FIG. 4 , when the first masking interval MP ends, the signal detection module 54 immediately returns to the initial state IS. The mask state MS is not entered again until the first title signal CP1 , the second title signal CP2 and the address mark signal are simultaneously detected again. If the signal detection module 54 only detects the first header signal CP1 and the second header signal CP2 after returning to the initial state IS, but does not receive the address mark signal, the signal detection module 54 will remain in the initial state IS. The timing diagram of generating the masking signal in this embodiment is shown in FIG. 4 , masking signal 2 .

Although the second embodiment can improve the correctness of identifying the title area 16 when the optical drive reads the optical storage medium. But Fig. 4 specific embodiment two also has its shortcoming sometimes. Because the optical drive sometimes does not send the address mark signal when reading the optical storage medium. In the second embodiment of FIG. 4 , near the header area 16 where the address mark signal has not been sent, the optical drive may be affected by wrong CP1' and CP2', so that the function of correctly pointing out the header area 16 cannot be achieved.

The present invention proposes a method in another specific embodiment to solve the problem of the second specific embodiment. According to the first embodiment, the signal detection module 54 stays in the masking state MS within a certain number of intervals after entering the masking state MS for the first time. During this period, although the signal detection module 54 only receives the first header signal CP1 and the second header signal CP2 but does not receive the address mark signal, it remains in the masked state MS. When the specific number of intervals is exceeded and the signal detection module 54 has not received the address mark signal, the signal detection module 54 returns to the initial state IS after the masked interval MP of the predetermined number of intervals ends. The mask state MS is not entered again until the signal detection module 54 detects the first title signal CP1 , the second title signal CP2 and the address mark signal simultaneously again.

For example, please refer to the third embodiment in FIG. 4 . Assume that the number of specific intervals of the signal detection module 54 is two. After confirming the first header area 16, although the address mark signal of the second header area 16 is not received, it remains in the masked state MS. But after the end of the second masking interval MP, if the address mark signal of the third header area 16 has not been received, then after the end of the third masking interval MP, return to the initial state IS. In FIG. 4, the time to return to the initial state IS is represented by the time axis T1.

The signal detection module 54 does not enter into the next masking state MS until the first title signal CP1 , the second title signal CP2 and the address mark signal are simultaneously detected again. The masking signal generated in this embodiment is shown in masking signal 3 in FIG. 4 .

According to the standard of DVDRAM, if the header area 16 missed in the specific section number causes data reading error, it can be corrected by the error correction program of the optical drive. Therefore, unlike the first embodiment, when the clock is unstable, data decoding errors will not be directly caused due to too many error sectors that can be corrected by the error correction program of the optical drive. Therefore, according to the third embodiment in FIG. 4 , as long as the number of header areas that do not send address mark signals is less than the number of specific sections, the optical drive can correctly identify the header area 16 . The third embodiment in FIG. 4 not only avoids the problems of the second embodiment, but also further improves the recognition accuracy of the title area 16 by the optical disc drive. To implement the third embodiment, the optical discrimination system 50 in FIG. 3 may further include a counter (not shown in FIG. 3 ) for calculating the number of specific intervals. The following describes how the optical discrimination system 50 applies the counter to implement the third embodiment in FIG. 4 . See Figure 5. FIG. 5 is a flow chart of the steps of the optical judging method of the third specific embodiment in FIG. 4 .

The optical judgment method comprises the following steps:

Step S30: start;

Step S32: receiving a reflected light beam reflected from the optical storage medium;

Step S34: Generate the first title signal CP1, the second title signal CP2 and the address mark signal according to the reflection position of the reflected light beam;

Step S36: When the first title signal CP1, the second title signal CP2 and the address mark signal appear successively, it is judged that the reflected light beam is reflected from one of the title areas 16;

Step S38: Turn the signal detection module 54 from the initial state IS to the masking state MS, and generate a corresponding masking signal, the length of which is a masking interval MP;

Step S40: After the masking interval MP ends, the signal detection module 54 detects whether the first title signal CP1, the second title signal CP2 and the address mark signal are detected at the same time, if yes, the counter is reset to zero, otherwise, the counter is incremented;

Step S42: Check whether the value of the counter has reached a set value, which is 2 in this embodiment.

If so, then the signal detection module 54 gets back to the initial state IS, continues step S36, otherwise proceeds to step S40;

Step S44: The signal detection module 54 remains in the shielded state MS, and repeats Step S40. .

The invention provides an optical judging system and its method, which are used to judge whether a reflected light beam is reflected from several title areas of an optical storage medium. The optical discrimination system includes a light beam detection module and a signal detection module. When a reflected light beam is reflected by a first recording position of the header area, a first header signal is generated. When the reflected light beam is reflected by a second recording position of the header area, a second header signal is generated. When there is an address information in the reflected beam, an address mark signal is generated. When the first title signal and the second title signal are successively received and the address mark signal is received during this period, it is judged that the reflected light beam is reflected from one of the title areas.

Compared with the prior art, the present invention utilizes the first title signal, the second title signal and the address mark signal to identify the title area at the same time, which can reduce the error in identifying the title area caused by the wrong first title signal and the second title signal. Conditions that lead to read errors. The present invention further shields the wrong first title signal and the second title signal by generating the shielding signal, so as to achieve the purpose of reducing interference.

Through the detailed description of the preferred specific embodiments above, it is hoped that the features and spirit of the present invention can be described more clearly, rather than limiting the scope of the present invention by the preferred specific embodiments disclosed above.

On the contrary, the intention is to cover various changes and equivalent arrangements within the scope of the patent application for the present invention.

Claims (23)

1. optics judgement system, be used to differentiate a folded light beam and whether reflect a plurality of header areas (header) on an optical storage media, this folded light beam system is emitted by an optical read-write device, and via the reflection of this optical storage media and produce, respectively this header area comprises one first record position and one second record position to write down an address information, and this optics judgement system comprises:

A beam detection module is in order to receive this folded light beam; Wherein

When this folded light beam is by this first record position reflex time, produce one first header signal;

When this folded light beam is by this second record position reflex time, produce one second header signal; And

When having this address information in this folded light beam, produce an address mark signal; And

A signal detection module is used for

Receive this first header signal, this second header signal and this address mark signal;

Wherein ought receive this first header signal and this second header signal in succession, and when receiving this address mark signal during this period, differentiating this folded light beam is that reflection is from one of these header areas.

2. optics judgement system as claimed in claim 1, wherein this signal detection module has an original state and a shielding status, when this signal detection module is preset in this original state, when this signal detection module receives this first header signal and this second header signal in succession, and when receiving this address mark signal during this period, differentiate this folded light beam and be reflection from one of these header areas, this signal detection module also is converted to this shielding status by this original state.

3. optics judgement system as claimed in claim 2 wherein when this signal detection module is in this shielding status, can produce this first header signal and this second header signal that a mask signal receives with shelter.

4. optics judgement system as claimed in claim 3 further comprises a counter (counter), is used to calculate the length between a shielded area of this mask signal.

5. optics judgement system as claimed in claim 4, wherein the length between this shielded area is unit of account with byte (byte), the calculating of can starting from scratch of this counter, when counter calculates one first special value, begin between this shielded area, after counting down to one second special value, finish between this shielded area.

6. optics judgement system as claimed in claim 5, the distance between this first special value and this second special value wherein is the length between this header area respectively.

7. optics judgement system as claimed in claim 5, wherein this signal detection module periodically sends this mask signal under this shielding status.

8. optics judgement system as claimed in claim 5, wherein work as this signal detection module and receive this first header signal and this second header signal in succession, and when during this, receiving this address mark signal, this counter can be reset to a special value.

9. optics judgement system as claimed in claim 5, wherein when finishing between this shielded area, this signal detection module can be converted to this original state.

10. optics judgement system as claimed in claim 5, wherein when this signal detection module after finishing between this shielded area, when not receiving this address mark signal, then continue to remain on this shielding status.

11. optics judgement system as claimed in claim 10, wherein this signal detection module keeps this shielding status in a specific interval number, when not receiving this address mark signal yet above this specific interval number, this signal detection module turns back to this original state.

12. optics judgement system as claimed in claim 11 further comprises a counter, in order to calculate this specific interval number.

13. optics judgement system as claimed in claim 3, wherein this signal detection module further comprises one first logic unit, in order to receive this first header signal and this mask signal, and when receiving this first header signal and this mask signal simultaneously, then cover this first header signal.

14. optics judgement system as claimed in claim 3, wherein this signal detection module further comprises one second logic unit, in order to receive this second header signal and this mask signal, and when receiving this second header signal and this mask signal simultaneously, then cover this second header signal.

15. optics method of discrimination, be used to differentiate a folded light beam and whether reflect a plurality of header areas (header) on an optical storage media, this folded light beam is emitted by an optical read-write device, and via the reflection of this optical storage media and produce, respectively this header area comprises one first record position and one second record position to write down an address information, and this optics method of discrimination may further comprise the steps:

Receive the folded light beam of this reflection from this optical storage media;

When this folded light beam is by this first record position reflex time, produce one first header signal;

When this folded light beam is by this second record position reflex time, produce one second header signal;

When having this address information in this folded light beam, produce an address mark signal; And

When occurring this first header signal and this second header signal in succession, and when this address mark signal also occurring during this period, differentiating this folded light beam is that reflection is from one of these header areas.

16. optics method of discrimination as claimed in claim 15, further comprise a signal detection module, wherein this signal detection module has an original state and a shielding status, when this signal detection module is preset in this original state, when this signal detection module receives this first header signal and this second header signal in succession, and when receiving this address mark signal during this period, differentiate this folded light beam and be reflection from one of these header areas, this signal detection module also is converted to this shielding status by this original state.

17. optics method of discrimination as claimed in claim 16 wherein when this signal detection module is in this shielding status, then can produce this first header signal and this second header signal that a mask signal receives with shelter.

18. optics method of discrimination as claimed in claim 17, wherein when this signal detection module received this first header signal and this mask signal simultaneously, this mask signal can cover this first header signal; When this signal detection module received this second header signal and this mask signal simultaneously, this mask signal can cover this second header signal.

19. optics method of discrimination as claimed in claim 17, wherein the length of this mask signal activation (Active) is between a shielded area.

20. optics method of discrimination as claimed in claim 17, wherein this signal detection module periodically sends this mask signal under this shielding status.

21. optics method of discrimination as claimed in claim 19, wherein when finishing between this shielded area, this signal detection module can be converted to this original state.

22. optics method of discrimination as claimed in claim 19, when this signal detection module after finishing between this shielded area, during receiving this first header signal or this second header signal, when not receiving this address mark signal, continue to remain on this shielding status.

23. optics method of discrimination as claimed in claim 22, wherein this signal detection module keeps this shielding status in a specific interval number, when not receiving this address mark signal yet above this specific interval number, this signal detection module turns back to this original state.

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