JP3477711B2 - Optical disc reproducing apparatus and layer error correction program used in the apparatus - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention
The present invention relates to an optical disc reproducing apparatus for reproducing a two-layer optical disc such as a rsatile disc) and a layer error correction program used in the apparatus.

[0002]

2. Description of the Related Art An optical disk reproducing apparatus for reproducing a two-layer optical disk such as a DVD has a basic structure capable of reproducing data recorded in each of the inner and outer layers of each track as needed.

In the case of a two-layer optical disk, there are two points where the laser beam is focused, the inner layer and the outer layer. Depending on the characteristics of the optical pickup unit used in the same device and the influence of noise, etc., the layer to be reproduced. May be wrongly focused on the outer layer or the inner layer even though is the inner or outer layer.
In the same apparatus, in order to correct such a layer error, the layer information included in the lead-in of each track of the two-layer optical disk is read every time the track to be reproduced is changed, and the layer error of the layer error is read based on this. Determine the presence,
When there is a layer error, the focus is jumped to the correct layer.

[0004]

However, in the case of the above-mentioned conventional example, since the presence or absence of the layer error is determined after the automatic adjustment or the data read, when the layer error is present and is corrected, the data read or the like is performed again. As a result, it takes a long time before the reproduction is actually started, and in this respect, it is pointed out that the usability is poor.

However, Japanese Laid-Open Patent Publication No. 11-96568 discloses a structure of an optical disc reproducing apparatus capable of correcting a layer error without using layer information recorded on an optical disc, but the focus is Since a focus error signal or the like is used to determine the number of a layer that matches with, there is an essential drawback in that it is very complicated and the cost is high in this respect.

The present invention was created under the above circumstances, and an object of the present invention is to provide an optical disk reproducing apparatus and the same apparatus capable of correcting a layer error even though it is a very simple method. It is to provide a layer error correction program to be used.

[0007]

An optical disk reproducing apparatus of the present invention is an apparatus for reproducing a two-layer optical disk, which starts a focus search from the inside or outside of the optical disk.
A data recording unit in which the data of the focus required time set in the middle of the time required for the focus to match the inner layer of the track of the optical disk and the time required to match the outer layer of the track for each track are recorded in advance. When reproducing the data recorded on the layer of the track of the optical disk after the focus search, a timer unit that starts counting when the focus search is started,
The time indicated by the counting result of the timer unit when the focus is achieved is compared with the focus required time corresponding to the track read from the data storage unit, and based on the comparison result, the focus is the inner layer of the track, the outer layer. It is characterized by including a layer error correction unit that determines which of the layers matches and, when the layer does not match the layer to be reproduced, causes the layer to perform a focus jump.

The layer error correction program used in the optical disc reproducing apparatus of the present invention is a program processed by a control microcomputer incorporated in the optical disc reproducing apparatus for reproducing a two-layer optical disc, and is inside or outside the optical disc. The focus search is started from, and the data of the focus required time set in the middle of the time required for the focus to match the inner layer of the track of the optical disk and the time required for the focus to match the outer layer of the track are preset for each track. When prepared, first, after the focus search, when reproducing the data recorded on the layer of the track of the optical disc, counting is started at the time when the focus search is started, and the count result when the focus is achieved is displayed. The indicated time and the track corresponding to the track prepared in advance The required time is compared to determine whether the focus is on the inner layer or outer layer of the track based on the result of this comparison, and if it does not match the layer to be played, a focus jump is performed on the layer. The feature is that it is the content to be performed.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram of an optical disk reproducing apparatus, and FIG. 2 is a flowchart of a layer error correction program used in the apparatus.

The optical disk reproducing apparatus listed here is an apparatus for reproducing the optical disk 1 which is a two-layer optical disk as shown in FIG.

Reference numeral 2 in the drawing denotes a drive unit for rotating the optical disc 1. Reference numeral 3 in the figure denotes an optical pickup unit that irradiates the signal recording surface of the optical disc 1 with laser light and detects the reflected light. Reference numeral 4 in the figure denotes a servo circuit for performing focus servo and tracking servo of the optical pickup unit 3, which also has a function of outputting a servo detection signal γ indicating a servo state.

In the figure, reference numeral 5 indicates a detection signal α of the optical pickup unit 3.
Is a signal generation unit that reproduces the data recorded on the optical disc 1 based on the above, and also generates various error signals β of a focus error and a tracking error from the detection signal α. Reference numeral 6 in the figure is a control microcomputer for controlling the entire apparatus according to an operation switch (not shown), to which various error signals β and servo detection signals γ are input, and the focus servo of the optical pickup unit 3 through the servo circuit 4, It has a function of controlling tracking servo and the like.

The control microcomputer 6 includes a CPU 61 and a memory 6.
2 and the like, and the control program for exhibiting the above-mentioned functions is recorded in the memory 62. The description so far is no different from the conventional example. However, in the present embodiment, the data of the required focusing time described later is recorded in the memory 62. This is the data storage unit 621
It is expressed as. Further, the layer error correction program shown in FIG. 2 is newly recorded. The program is C
By being processed by the PU 61, the CPU 61 can function as a timer unit 611 and a layer error correction unit 612 described later.

That is, the optical disk reproducing apparatus according to the present embodiment starts the focus search from the inside of the optical disk 1 until the focus reaches the inner layer of the track of the optical disk 1 and the outer layer of the track. The focus search is started when reproducing the data recorded on the layer of the track of the optical disc 1 and the data recording section 621 in which the data of the focus required time set in the middle of the time required for A timer unit 611 that starts counting at the time
The time indicated by the counting result of the timer unit 611 when the focus is achieved is compared with the focus required time corresponding to the track read from the data storage unit 621, and based on the comparison result, the focus is the inner layer of the track. , Determine which of the outer layers it fits in,
When the layer does not match the layer to be reproduced, the layer error correction unit 612 that causes the layer to perform a focus jump
It is configured with and. This is the most characteristic configuration of this plan.

Here, the data of the required focusing time will be described. For example, attention is paid to the inner layer a1 and outer layer a2 of the track a on the data recording surface of the optical disc 1. Focus search is started from the innermost reference point of the optical disc 1, and respective times required for the focus to match the inner layer a1 and outer track a2 of the track a are t1 and t2. Here, (t1 + t2) / 2 is the data of the focusing time of the track a (this is FDA
TAa). The data recording unit 621 measures such data for all the tracks of the optical disc 1 and records it in the memory 62.

Next, the contents of the layer error correction program shown in FIG. 2 will be described, and also the operation of the optical disk reproducing apparatus configured as described above will be described.

The program is processed when reproducing the data recorded on the layer of the track of the optical disk 1 after the focus search. While the optical disk 1 is being reproduced, the tracks to be reproduced change one by one, but this is not the case, and a reproduction switch or the like (not shown) is operated,
It is processed when the track to be reproduced changes greatly. Here, the inner layer a of the track a of the optical disc 1
The case of reproducing the data above 1 will be described.

First, the focus is returned to the innermost reference point of the optical disc 1 to start the focus search. Then, when the focus search is started, the counting of the timer unit 611 is started (s1).

Thereafter, it is determined based on various error signals whether or not the focus is achieved (s2), and when the focus is achieved, the timer unit 611 stops counting (s).
3). Then, the time indicated by the counting result of the timer unit 611 and the focus required time corresponding to the track a prepared in advance in the data storage unit 621 are compared in magnitude (s4).

Based on the comparison result, it is determined whether the focus is on the inner layer a1 or the outer layer a2 of the track a. That is, when the time indicated by the counting result of the timer unit 611 is larger than FDATAa, it is determined that the focus is on the outer layer a2,
When it is smaller, it is determined that it matches the inner layer a1 (s4).

Next, the presence or absence of a layer error is determined based on this determination result. Since the data on the inner layer a1 of the track a of the optical disc 1 is reproduced, when the focus is on the inner layer a1, it is determined that there is no layer error, and the program ends. On the other hand, when the focus is on the outer layer a2, it is determined that there is a layer error, and in this case, the focus is jumped to the inner layer a1 (s
6). If the outer layer a of the track a of the optical disc 1
If the data of No. 2 is to be reproduced, the procedure is completely opposite to the above. When the focus is on the inner layer a1, the focus is jumped to the outer layer a2. Then, the program ends.

When the program is finished, the process returns to the process of the conventional main control program, and the optical disc 1 is processed as usual.
After the data is read from the track a, the data on the inner layer a1 of the track a of the optical disc 1 is reproduced. Then, the tracks to be reproduced are sequentially changed so that the data recorded on the optical disc 1 is sequentially reproduced from the track a. Here, the case of reproducing the data on the inner layer a1 of the track a of the optical disc 1 has been described, but the same is true for the case of reproducing the data of other tracks.

In the case of the optical disk reproducing apparatus having the above-mentioned structure, even if a layer error occurs due to the characteristics of the optical pickup unit 3 used in the apparatus, noise, etc., it is possible that the error occurs before the lead-in is performed. Since it is configured to correct layer errors, the time until the playback is actually started when the playback switch (not shown) is operated is shortened compared to the past, and the usability is improved in this respect. . Moreover, since the above functions can be realized only by changing the design of software, there is an advantage in achieving cost reduction and high performance of the device. In particular, since the presence / absence of a layer error can be recognized by a simple method of measuring the time of the focus search, the software itself is also simple, and this is also advantageous in terms of cost.

The optical disk reproducing apparatus according to the present invention is not limited to the above-mentioned embodiment, and can be applied to an optical disk such as a CD. Further, although the focus search is started from the inner side of the optical disk in the above embodiment, the focus search may be started from the outer side. In this case, when determining whether or not there is a layer error, the time indicated by the count result of the timer unit when the focus is achieved and the focus required time read from the data storage unit are compared, and the focus is inside the track. The correspondence is exactly the same except that the correspondence relation between the layer and the outer layer is opposite. Furthermore, the functions of the timer unit and the layer error correction unit may be realized by hardware.

[0025]

As described above, according to the optical disc data reproducing apparatus of the present invention and the layer error correction program used in the apparatus, even if a layer error occurs due to the influence of the characteristics of the optical pickup unit, noise, etc., the read operation is performed. Since the layer error is corrected before the input is performed, the time until the reproduction is actually started is shortened as compared with the case of the conventional example, and the usability is improved in this respect. Moreover, since the presence / absence of a layer error is recognized by a simple method of measuring the time for focus search, there is an advantage in achieving cost reduction and high performance.

[Brief description of drawings]

FIG. 1 is a diagram for explaining an embodiment of the present invention and is a block diagram of an optical disk reproducing device.

FIG. 2 is a flowchart of a layer error correction program used in the device.

[Explanation of symbols]

1 optical disc 3 Optical pickup section 6 Control microcomputer 611 timer part 612 Layer error correction unit 621 data storage unit

Claims (2)

(57) [Claims] 1. An optical disc reproducing apparatus for reproducing a dual-layer optical disc, wherein a time required for starting a focus search from the inside or outside of the optical disc to bring the focus into alignment with an inner layer of a track of the optical disc and an outer layer of the track. The focus search was started to reproduce the data recorded in the data recording part in which the data of the focus required time set in the middle of the time required for A timer unit that starts counting at a time point,
The time indicated by the counting result of the timer unit when the focus is achieved is compared with the focus required time corresponding to the track read from the data storage unit, and based on the comparison result, the focus is the inner layer of the track, the outer layer. An optical disk reproducing apparatus, comprising: a layer error correction unit that determines which of the layers matches and, if the layer does not match the layer to be reproduced, causes the layer to perform a focus jump. 2. A layer error correction program processed by a control microcomputer incorporated in an optical disc reproducing apparatus for reproducing a two-layer optical disc, wherein focus search is started from inside or outside of the optical disc, and the focus is on the optical disc. When the data of the focus required time set in the middle of the time required to fit the inner layer of the track and the time required to fit the outer layer of the track is prepared in advance for each track, When reproducing the data recorded on the layer, the counting is started when the focus search is started, and the time indicated by the count result when the focus is achieved and the focus required time corresponding to the track prepared in advance Are compared with each other, and the focus is adjusted to the It is used for an optical disk playback device characterized by determining whether it is in the inner layer or the outer layer of the track, and when it does not match the layer to be played back, the content is made to perform a focus jump. Layer error correction program.