JP2000260109A - Disk discriminating method and optical disk recording and reproducing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To exactly discriminate the kind of disk at all the time without depending on the sensitivity, control voltage and current of an actuator. SOLUTION: Concerning this disk discriminating method, a pickup is perpendicularly moved to an optical disk while irradiating the optical disk with laser light from the pickup, a reflect signal 1 showing the focusing of laser light provided at that time on the surface of the optical disk and first and second peak signals 2 and 3 to appear before and after focusing the pit surface of the optical disk with the laser light are measured, first time 4 between the reflect signal 1 and the first peak signal 2 and second time 5 between the first and second peak signals 2 and 3 are found, the ratio 4/5 of these times is calculated and from this ratio calculated result, it is discriminated whether the optical disk is CD disk or DVD disk. The dispersion in the moving speed of the pickup caused by the dispersion in the sensitivity, control voltage and current of the actuator is absorbed by the said ratio calculation and the kind of disk can be exactly discriminated at all the time.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical disk recording / reproducing apparatus such as a DVD player and, more particularly, to a method for determining a type of a disk to be recorded / reproduced.

[0002]

2. Description of the Related Art Conventionally, as an optical disk reproducing apparatus, C
There are a D-ROM drive, a DVD-ROM drive, a CD player, a DVD player, a video CD player, and the like. In these players, for example, it is determined whether a disc to be reproduced is a CD or a DVD. Reproduction is performed.

First, when discriminating the disk, as shown in FIG.
The pickup 2 is moved from top to bottom or from bottom to top by an actuator (not shown). At this time, if the disc 1 is a single-layer DVD disc, an SBAD (sub-beam addition) signal and an FE (focus error) signal as shown in FIGS. 5A and 5B can be obtained.

FIGS. 5C and 5D show an SBAD signal and an FE signal of a dual-layer DVD disk, respectively.
FIGS. 5E and 5F show the SBAD signal and F of the CD disk.
This is the E signal.

Here, the peak of the signal indicated by (1) in FIG. 5 is a reflection signal due to reflection when the laser beam focuses on the surface of the disk 1. (2) is FE
At the zero-cross point of the signal, the focus of the laser beam is
, Which indicates the focus point of the laser beam.

By the way, according to the disc standard, DVD
In the case of a disc, the distance from the surface to the focus point is 0.570 mm for a single layer disc,
It is defined as 0.550 mm for a dual layer disc and 1.2 mm for a CD disc.

Therefore, in the prior art, the time between the peak of the reflected signal (1) of the SBAD signal and the zero cross point (2) of the FE signal in FIG. 5 was measured to discriminate the CD / DVD disk.

That is, the time from the reflection signal (1) to the zero crossing point (2) in FIG. 5 is different between the DVD disk and the CD disk, and the CD disk is longer than the DVD disk. And a CD disk.

When the disc 1 is discriminated as a DVD disc, whether it is a single-layer disc or a dual-layer disc is determined by the number of focus points of the FE signal shown in FIGS. If the number of focus points is one, the disc is determined to be a single layer disc, and if the number of focus points is two, the disc is a dual layer disc.

[0010]

In the above-described conventional method for discriminating a disc in an optical disc reproducing apparatus, the SBAD shown in FIG.
The time from the signal reflection point (1) to the FE signal focus point (2) varies depending on the moving speed of the pickup, that is, the sensitivity, control voltage, and current of the actuator for moving the pickup. The time difference for discrimination varies. If the variation in the time difference is large, erroneous discrimination of the disk occurs,
There is a problem that the discrimination rate of the disc is lowered.

The above-mentioned problem occurs not only in an optical disk reproducing apparatus but also in an optical disk recording apparatus that determines the type of a disk and then records data on the disk.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned conventional problems, and an object thereof is to always accurately determine the type of a disk regardless of the sensitivity, control voltage, and current of an actuator. It is an object of the present invention to provide a disc discriminating method that can be used and an optical disc recording / reproducing apparatus using the discriminating method.

[0013]

In order to achieve the above object, a feature of the present invention is to determine the type of the optical disc when recording or reproducing data by irradiating the optical disc with a laser beam from a pickup. In the disc discriminating method, the pickup is moved in a direction perpendicular to the optical disc while irradiating laser light from the pickup, and a reflection signal indicating that the laser light obtained at that time is focused on the surface of the optical disc and the reflected signal. First and second peak signals appearing before and after the laser light is focused on the pit surface of the optical disk are measured, and a first time between the reflection signal and the first peak signal and the first and second peak signals are measured. A second time between them is calculated, and these times are ratio-calculated, and the type of the optical disc is determined based on the ratio calculation result. It is to.

According to the first aspect of the present invention, the first time between the reflection signal and the first peak signal differs depending on the type of the optical disk, but the second time between the first and second peak signals is different. Since it hardly changes, for example, the first time / second time
The time value differs depending on the type of the optical disc. Therefore, by obtaining this value, the type of the optical disk can be specified.

A feature of the invention according to claim 2 is that the type of the optical disk is determined based on a value obtained by dividing the first time by the second time.

A feature of the invention according to claim 3 is that the first and second features are provided.
Instead of determining the second time between peak signals, the first,
The area of two regions formed between the waveform of the second peak signal and the reference voltage line is determined, and the sum of the areas of the two regions is used instead of the second time.

A feature of the invention according to claim 4 is that it is determined whether the disc is a single layer disc or a dual layer disc based on the number of zero cross points or peak points indicating that the focal point of the laser beam is focused on the pit surface of the optical disc. It is in.

According to a fifth aspect of the present invention, there is provided an optical disc recording / reproducing apparatus for recording or reproducing data by irradiating an optical disc with a laser beam from a pickup, wherein the pickup irradiates the optical disc with the laser beam while irradiating the optical disc with the laser beam. Means for moving at right angles,
During the movement of the pickup, a reflection signal indicating that the laser light is focused on the surface of the optical disk and first and second peak signals appearing before and after the laser light is focused on the pit surface of the optical disk are measured. Means for determining a first time between the measured reflected signal and the first peak signal and a second time between the first and second peak signals, and calculating a ratio of these times; Means for determining the type of the optical disk based on the ratio calculation result.

According to a sixth aspect of the present invention, the first and second aspects are characterized.
Instead of determining the second time between peak signals, the first,
The area of two regions formed between the waveform of the second peak signal and the reference voltage line is determined, and the sum of the areas of the two regions is used instead of the second time.

[0020]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing a first embodiment of the optical disk recording / reproducing apparatus of the present invention. A disc discrimination system of the optical disc recording / reproducing apparatus includes a pickup 2 for irradiating a laser beam to the disc 1, a signal processing unit 3 for processing a signal obtained from the pickup 2 to generate an FE (focus error) signal and an SBAD signal, The FE signal or SBAD obtained from the signal processing unit 3
A / that converts analog signals such as signals to digital signals
The D / D converter 4 includes a disc discrimination processing section 5 for discriminating the type of the disc 1 based on the digitized FE signal and SBAD signal input from the A / D conversion section 4.

The system control unit 6 performs recording / reproduction control and the like, and performs recording or reproduction control corresponding to the type of the set disc based on the discrimination result of the disc discrimination processing unit 5.

Next, the operation of this embodiment will be described. During disc discrimination, the pickup 2 moves in a direction perpendicular to the disc 1 by an actuator (not shown) while irradiating the disc 1 with laser light. At this time, the signal obtained from the pickup 2 is processed by the signal processing unit 3 to generate an FE signal and an SBAD signal. These signals are digitized by the A / D conversion unit 4 and input to the disc discrimination processing unit 5. You.

The disc discriminating unit 5 discriminates the disc 1 based on the input FE signal and SBAD signal, and supplies the result to the system control unit 6.

First, while irradiating the disk 1 with laser light from the pickup 2 as described above, the pickup 2 is moved from top to bottom or from bottom to top.

As a result, S as shown in FIG.
As the BAD signal, an FE signal as shown in FIG. 2B is obtained. However, the peak of the signal in (1) is a reflection signal due to reflection when the laser beam focuses on the surface of the disk 1. The zero-cross point of the FE signal is when the focus of the laser light hits the pit surface of the disk 1, that is, the focus point of the laser light, and before and after this focus point, the peak signals (2) and (2) of the FE signal 3) appears.

Therefore, the disk discrimination processing unit 5 measures the time from the peak of the reflected signal (1) of the SBAD signal to the peak of the peak signal (2) of the FE signal in FIG. Further, the time from the peak of the peak signal (2) of the FE signal in FIG. 2 to the peak of the peak signal (3) appearing conversely is measured, and is defined as (5).

Then, the ratio of (4) / (5) is calculated,
The type of the disc 1 is determined based on the ratio calculation result. That is, the ratio calculation result is larger when the disk 1 is a CD disk than when it is a DVD disk. This is because the length of (4) differs depending on the type of the disc 1 (the CD is longer), but the length of (5) hardly changes. Thus, the disc discrimination processing unit 5 can discriminate the type of the disc 1.

According to the present embodiment, the above (4) /
Since the type of the disc 1 is determined based on the ratio calculation result of (5), when the sensitivity, control voltage, and current of the actuator for moving the pickup 2 vary, (4)
And (5) vary, but the ratio of (4) / (5) becomes almost constant. As a result, in this embodiment, the type of the disk 1 can always be accurately determined regardless of the sensitivity, control voltage, and current of the actuator.

In this example, after the disc 1 is determined to be a DVD disc, the number of zero-cross points (or the number of peak points of the FE signal) of the obtained FE signal indicates whether the disc 1 is a single-layer disc or a dual-layer disc. Is determined.

FIG. 3 is a signal waveform diagram showing a main part of a second embodiment of the optical disk recording / reproducing apparatus of the present invention.
In this example, the peak signals (2) and (3) appearing in the FE signal
Since the configuration of the apparatus is the same as that of the previous embodiment except that the method of obtaining the time from the top to the top of this embodiment is different from that of the previous embodiment, the configuration of FIG.

In discriminating the disc in this embodiment, the pickup 2 is moved from top to bottom or from bottom to top while irradiating the disc 1 with laser light from the pickup 2. Thereby, the SBAD signal and the FE signal as shown in FIG. 3 are obtained from the signal processing unit 3.

Thereafter, the time from the peak of the reflected signal (1) of the SBAD signal to the peak of the peak signal (2) of the FE signal in FIG. 3 is measured, and this is defined as (4). Also, F in FIG.
The area of the hatched portion surrounded by the E signal reference voltage and the peaks (2) and (3) of the FE signal is measured at regular intervals, and is defined as (6).

Next, the ratio of (4) / (6) is calculated,
Based on the result, the type of the disc 1 is determined.

Here, (6), which is the area of the hatched portion surrounded by the FE signal reference voltage and the FE signal in FIG. 3, is the time from peak to peak of the peak signals (2) and (3) of the FE signal. It turns out that the value is proportional.

Accordingly, the result of the ratio calculation of (4) / (6) obtained using the area (6) of the hatched portion is larger when the disc 1 is a CD than when it is a DVD. Therefore, the disc determination processing unit 5 can thereby determine the type of the disc 1.

In this embodiment, when the sensitivity of the actuator, the control voltage, and the current vary,
(4) and (6) vary, respectively, but (4) / (6)
Is almost constant, and the same effect as in the previous embodiment can be obtained.

The above SBAD signal is always obtained when the three-beam type pickup 2 is used.
Even when the beam type pickup 2 is used, the SB
Since a signal equivalent to the AD signal is obtained, the same effect can be obtained by applying the above-described disc determination method of the present invention.

In the above embodiment, the pickup 2
A / D conversion is performed on the signal obtained from the above, and the disc is discriminated digitally. However, the disc discriminating method of the present invention can be realized by an analog circuit together with the first and second embodiments. .

[0039]

As described above in detail, according to the present invention, the value used for disc discrimination is obtained by the ratio calculation, so that the disc can always be accurately obtained regardless of the sensitivity, control voltage and current of the actuator. The type can be determined.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a first embodiment of an optical disk recording / reproducing apparatus according to the present invention.

FIG. 2 is a signal waveform diagram for explaining a disc discriminating method in the apparatus shown in FIG.

FIG. 3 is a signal waveform diagram showing a main part of a second embodiment of the optical disk recording / reproducing apparatus of the present invention.

FIG. 4 is a diagram for explaining a conventional disc determination method.

FIG. 5 is a signal waveform diagram for explaining a conventional disk discriminating method.

[Explanation of symbols]

 Reference Signs List 1 disk 2 pickup 3 signal processing unit 4 A / D conversion unit 5 disk discrimination processing unit 6 system control unit

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Yuji Takanishi 580 Horikawa-cho, Saiwai-ku, Kawasaki-shi, Kanagawa F-term in Toshiba LSI System Support Co., Ltd. 5D066 HA01 5D117 AA02 CC07 DD03 FF01 FF02 FX08

Claims (6)

[Claims] 1. A disc discriminating method for discriminating the type of an optical disc when recording or reproducing data by irradiating the optical disc with a laser beam from a pickup, comprising: A pickup is moved in a right angle direction, and a reflected signal indicating that the laser light obtained at that time is focused on the surface of the optical disk and first and second peak signals appearing when the laser light is focused on the pit surface of the optical disk. Is measured, a first time between the reflection signal and the first peak signal and a second time between the first and second peak signals are obtained, and these times are ratio-calculated. Discriminating method for discriminating the type of a disc. 2. A disc discriminating method for discriminating a type of the optical disc when recording or reproducing data by irradiating the optical disc with a laser beam from a pickup, comprising: A pickup is moved in a right angle direction, and a reflected signal indicating that the laser light obtained at that time is focused on the surface of the optical disk and first and second peak signals appearing when the laser light is focused on the pit surface of the optical disk. And measuring the first time between the reflection signal and the first peak signal and the area of two regions formed between the waveforms of the first and second peak signals and the reference voltage line. A discriminator for discriminating the type of the optical disc based on a result of the ratio calculation; Law. 3. The method according to claim 1, wherein the type of the optical disk is determined based on a value obtained by dividing the first time by the second time. 4. A single-layer disc or a single-layer disc according to the number of zero-cross points or peak points indicating that the focus of the laser light is focused on the pit surface of the optical disc.
4. The disc discriminating method according to claim 1, wherein discrimination is made for a dual layer disc. 5. An optical disk recording / reproducing apparatus for recording or reproducing data by irradiating an optical disk with a laser beam from a pickup, means for moving the pickup in a direction perpendicular to the optical disk while irradiating the optical disk with the laser beam. A reflection signal indicating that the laser beam has focused on the surface of the optical disk while the pickup is moving, and first and second peak signals appearing before and after the laser beam focuses on the pit surface of the optical disk. Means for measuring a first time between the measured reflected signal and the first peak signal and a second time between the first and second peak signals, and calculating a ratio of these times. And means for determining the type of the optical disc based on the ratio calculation result. That optical disc recording and reproducing apparatus. 6. An optical disk recording / reproducing apparatus for recording or reproducing data by irradiating an optical disk with a laser beam from a pickup, means for moving the pickup in a direction perpendicular to the optical disk while irradiating the optical disk with the laser beam. A reflection signal indicating that the laser beam has focused on the surface of the optical disk while the pickup is moving, and first and second peak signals appearing before and after the laser beam focuses on the pit surface of the optical disk. Means for measuring the first time between the measured reflected signal and the first peak signal, and the area of two regions formed between the waveforms of the first and second peak signals and the reference voltage line. Means for calculating the ratio of these times, and discriminating the type of the optical disk based on the result of the ratio calculation. An optical disk recording / reproducing apparatus comprising: