KR100618793B1 - Determining method for the kind of optical disk - Google Patents

Abstract

The present invention relates to an optical disc recording / reproducing apparatus, and more particularly, to a method of determining a type of an mounted optical disc and a control method of an optical disc player suitable thereto.

An optical disc type determination method according to the present invention is a method for determining the type of an optical disc mounted in an optical disc player corresponding to a CD / CDR / CDRW / DVD, etc. (a) while changing the focus of an optical signal irradiated onto the mounted optical disc Detecting an elapsed time from when the surface reflection signal is generated to when the recording surface reflection signal is generated; And (b) comparing the detected elapsed time with a time corresponding to a CD or a time corresponding to a DVD, and determining whether the mounted optical disc is a CD type or a DVD type.

The optical disc determination method according to the present invention has the effect of increasing the adaptability of the CD / DVD-compatible optical disc player by determining the CD / DVD using the difference in the elapsed time from the generation of the surface reflection signal to the generation of the recording surface reflection signal.

Description

Determining method for the kind of optical disk}

1 is a cross-sectional view showing the structure of a CD.

2 is a flowchart illustrating a method of determining an optical disc type according to the present invention.

3 (a) and 3 (b) are waveform diagrams shown for explaining the elapsed time detection process S202 shown in FIG. 2.

4 is a flowchart showing a method of controlling an optical disc player according to the present invention.

5 is a waveform diagram showing a surface reflection signal and a focus error signal seen in the case of a CDR.

6 is a waveform diagram showing a surface reflection signal and a focus error signal seen in the case of a CD.

Fig. 7 is a waveform diagram showing a surface reflection signal and a focus error signal seen when the mounted optical disc is a CDR but it is incorrectly determined to be a CDRW.

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical disc recording / reproducing apparatus, and more particularly, to a method for determining the type of an optical disc mounted according to a difference in thickness and reflectance of an optical disc, and a control method of an optical disc player suitable thereto.

Generally, a DVD recorder / player can play both DVD-like discs such as DVD SINGLE and DVD DUAL and CD-like discs such as CD, CDR and CDRW. The type of optical disc must be accurately determined.

As a method of determining the type of the mounted optical disk, there are a method of using the reflectance of the optical disk, a sequential search method and the like. In the method of using the reflectance of the optical disk, the optical signal of a predetermined level is projected onto the optical disk by using the reflectance of the optical signal for each optical disk, and the type of the optical disk is determined according to the amount of light reflected therefrom. However, as the types of optical discs are diversified and the distribution of reflectances is diversified even in the same type of optical discs, it is difficult to accurately determine the type of optical discs by reflectance. In particular, some of the CDRs have a reflectance similar to that of the CDRW, which is often mistaken for a CDRW.

In order to determine the type of optical disk, the sequential search method assumes an arbitrary optical disk mode, and then reads the information of the lead-in area and determines that the optical disk mode is assumed if it meets the conditions corresponding to the assumed optical disk. It is a method of determining the type of optical disc by repeatedly reading and comparing the information of the lead-in area while changing the optical disc mode. This sequential search method has a problem in that it takes a long time to determine the type of the optical disc by determining the type of the optical disc by repeatedly reading and comparing the information of the lead-in area.

An object of the present invention is to provide an improved method for determining the type of optical disc, which has been devised to solve the above problems.

Another object of the present invention is to provide a control method for determining the type of optical disc in an optical disc player corresponding to a CD / DVD / CDR / CDRW.

In the optical disc type determination method according to the present invention for achieving the above object is a method for determining the type of optical disc mounted in the optical disc player corresponding to the CD / CDR / CDRW / DVD, etc. (a) Detecting an elapsed time from when the surface reflection signal is generated to when the recording surface reflection signal is generated while changing the focus of the signal; And (b) comparing the detected elapsed time with a time corresponding to a CD or a time corresponding to a DVD, and determining whether the mounted optical disc is a CD or a DVD. It features.

In accordance with another aspect of the present invention, a control method includes a CD LD (Laser Diode) corresponding to a CD / CDR / CDRW, a DVD LD corresponding to a DVD-single / DVD-dual, or the like. A control method for judging the type of a signal, comprising: detecting an occurrence point of a surface reflection signal, an occurrence point of a focus error signal, and a maximum value of a focus error signal while moving an objective lens closer to a recording surface of an optical disk under a CD LD condition. A first object lens up process; And a CD / DVD determination process of determining a CD / DVD using a generation time of the surface reflection signal detected in the objective lens up process and a generation time of the focus error signal.

Hereinafter, the configuration and operation of the present invention will be described in detail with reference to the accompanying drawings.

1 is a cross-sectional view showing the structure of a CD. As shown in Fig. 1, the CD is composed of a polycarbonate layer, an aluminum recording film, a protective film, a label, and the like from the bottom, and the total thickness is 1.2 cm. The optical signal emitted from the bottom of the CD is reflected on the surface or the recording surface. The signal reflected from the surface of the optical disc in this manner is called a surface reflection signal, and the signal reflected from the recording surface is called a recording surface reflection signal.

The signal reflected from the optical disc is converted into an electrical signal via a photodetector. An RF signal, a focus error signal, a tracking error signal, and the like are obtained from the output of the photodetector.

It has a constant thickness from the surface of the optical disk to the recording surface, which is about twice the thickness of DVDs. Since the DVD has a multilayer structure of at least two layers and the overall thickness is the same as that of the CD, the thickness from the surface to the recording surface is half that of the CD. Therefore, assuming that the moving speed of the objective lens is the same, the time from the time when the surface reflection signal appears to the time when the recording surface reflection signal appears is approximately doubled in the case of CD than in the case of DVD.

In the present invention, the CD and the DVD are judged by using the time difference from the time when the surface reflection signal is generated to the time when the recording surface reflection signal appears due to the thickness difference between the optical discs of the CD and the DVD.

On the other hand, the wavelength of an optical signal for reproducing a CD-based optical disc such as a CD, a CDR, a CDRW, and the wavelength of an optical signal for reproducing a DVD-based optical disc such as a DVD-single or a DVD-dual are different from each other. Accordingly, an optical disc recording / reproducing apparatus corresponding to a CD / DVD generally includes a laser diode (hereinafter referred to as CD LD) for generating an optical signal for reproducing an optical disc of a CD series and an optical signal for reproducing an optical disc of a DVD series. A laser diode (hereinafter referred to as DVD LD) that is generated is provided.

CD-CDRW can record 70-80% / 20-30% of the size of the recording surface reflection signal compared to the CD LD operation. Obtained. In the present invention, such a CD is used to determine other CD sequences and CDRs.

Typically, CDRs have lower reflectances than CDRWs, but some CDRs have similar reflectances as CDRWs, so that CDRs are considered CDRWs. In the present invention, if the gain setting according to the CDR and the CDRW is different and accordingly, when the CDR is set to the gain of the CDRW, the case where the CDR is incorrectly judged as the CDRW is determined by using a different size from the case where the recording plane reflection signal is normal, and the determination result is determined. Correct it.

2 is a flowchart illustrating a method of determining an optical disc type according to the present invention. The method shown in FIG. 2 detects the elapsed time from the time when the surface reflection signal is generated to the time when the recording surface reflection signal is generated in the state where the CD LD is operated (S202), and the CD / DVD is detected by the detected elapsed time. Determining (S204), detecting the size of the recording surface reflection signals in the state where the DVD LD is operated (S206), and determining the CD / CDR according to the detected recording surface reflection signals (S208), CDR Steps S216 and 218 of correcting that the CDR is incorrectly determined to be CDRW according to the gain setting of / CDRW are included.

In the elapsed time detection process (S202), the elapsed time T from the time when the surface reflection signal is generated to the time when the recording surface reflection signal is generated while moving the focus of the optical signal while the CD LD is operated is detected. Here, in order to easily detect the surface reflection signal and the recording surface reflection signal, the gain of the current-voltage converter for converting the electrical signal detected from the photodetector into the current-voltage is set to the maximum.

3 (a) and 3 (b) are waveform diagrams for explaining the elapsed time detection process S202 shown in FIG. 2, and FIG. 3 (a) shows a case where a DVD is mounted. 3 (b) shows a case where a CD is mounted.

As shown in Figs. 3A and 3B, s and s 'are surface reflection signals on DVD and CD, respectively, and f and f' are focus error signals obtained from recording surface reflection signals on DVD and CD, respectively. admit.

Comparing (a) and (b) of FIG. 3 , it can be seen that the time t from s to f and the time t 'from s' to f' are different. The difference between t and t 'is that the distance from the surface of the optical disk to the recording surface, that is, the thickness of the optical disk is different. Since the CD is about twice as thick as a DVD, t 'is about twice that of t.

 In the CD / DVD determination process (S204), the elapsed time T detected in the elapsed time detection process (S202) is compared with the time t corresponding to the DVD or the time t 'corresponding to the CD to determine whether the CD / DVD is present.

In the CD / DVD determination process (S204), if the elapsed time T detected in the elapsed time detection process (S202) corresponds to the time t 'corresponding to the CD, it is determined that the mounted optical disc is a CD, and at the time t corresponding to the DVD, If so, it is determined to be a DVD. The time t 'corresponding to the DVD and the time t corresponding to the CD are determined according to the moving speed of the objective lens, and the moving speed of the objective lens is set in consideration of the responsiveness of the servo system. When the moving speed of the objective lens is determined, the standard times can be determined with a standard CD or DVD mounted and used for the CD / DVD judgment.

If it is determined in the CD / DVD determination process (S204) that it is a DVD, the process branches to the DVD processing process. In the present invention, a detailed description of the DVD process is omitted.

In the size detecting process (S206), the size of the recording surface reflection signal is detected while moving the focus of the optical signal while the DVD LD is operated. The magnitude of the recording surface reflection signal can be obtained by using an RF signal or a focus error signal. However, since the magnitude of the RF signal changes when the disk rotates, it is preferable to use the focus error signal. In the magnitude detection process S206, the magnitude of the recording surface reflection signal is obtained as the maximum value of the focus error signal (peak to peak value).

In the CD / CDR determination process (S208), the CD / CDR is determined according to the magnitude of the recording surface signal detected in the size detection process (S106).

Under the DVD LD condition, the CDR has a characteristic of showing almost zero reflectance compared to other CD series optical disks, for example, CD / CDRW. In the CD / CDR determination process (S208), if the magnitude of the recording surface reflection signal measured under the DVD LD is less than or equal to the predetermined level by using this characteristic, it is determined as the CDR.

In the CD / CDRW determination process (S212), the CD / CDRW is determined by using the CDRW having a reflectance of 20-30% compared to the CD in the CD LD condition or the DVD LD condition.

If it is determined that the CD is a CD / CDRW determination process (S212), the process branches to the CD processing process. In the present invention, a detailed description of the CD processing is omitted.

If it is determined that the CDRW is in the CD / CDRW determination process (S212), the gain of the current-voltage converter processing the output of the photodetector is set to a gain suitable for the CDRW through the CDRW gain setting process (S214).

Some CDRs with high reflectance may not be determined as CDRs in the CD / CDR determination process (S208).

In this case, although the CDR is mounted, it is determined that it is not a CDR in the CD / CDR determination process (S208), and processes the output of the photodetector through the CD / CDRW determination process (S212) and the CDRW gain setting process (S214). Set the gain of the current-to-voltage converter appropriately for the CDRW. In this case, the gain of the CDR / CDRW (hereinafter, the gain refers to the gain of the signal processing system that processes the output of the photodetector and provides it to the servo system, and the signal processing system includes a current-voltage converter) is used. It is possible to correct a CDR that was incorrectly determined to be a CDRW.

In the signal size checking process (S216), whether the CDRs are determined to be CDRWs by using different gains of the CDRs / CDRWs.

Typically, the CDR has a reflectance almost equal to that of the CD, and since the CDRW has a reflectivity of about 1/2 of the CD, the gain of the CDRW is set to about twice that of the CD. Therefore, when the CDR is incorrectly determined as CDRW, the gain is set to about twice as large as when the gain is normally determined, so that the magnitude of the recording surface reflection signal is about twice as large as when normally determined. Using this, the magnitude of the recording surface signal is measured under the conditions of the CD LD, and accordingly, the CDR is incorrectly judged as the CDRW.

In the first CDR gain setting step S210 and the second CDR gain setting step S218, the gain of the current-voltage converter processing the output of the photodetector is set to a gain suitable for the CDR.

Processes flowing into the S216 process are only processes in which the CDR is judged normally as a CDR and processes in which the CDR is incorrectly determined as CDRW. In the former case, since the recording surface reflection signal must be generated within the normal range, the latter case is detected in step S216.

4 is a flowchart showing a method of controlling an optical disc player according to the present invention.

In general, the optical pickup including the objective lens is located under the optical disc, and the optical disc is mounted so that the recording surface is located far from the objective lens. When the objective lens is up, the focus of the optical signal moves from the surface of the optical disc toward the recording surface. On the contrary, when the objective lens is down, it moves from the recording surface of the optical disc toward the surface.

In the CD LD on process (S402), the power of the CD LD is turned on.

In the first objective lens down process (S404), the objective lens is brought down to prepare for detecting the surface reflection signal.

In the first objective lens up process (S406), the objective lens is up.

In the surface reflection signal detection process S408, it is determined whether the surface reflection signal has been detected. The time point at which it is determined that the surface reflection signal has been detected is, for example, the time when the maximum value of the surface reflection signal is detected or the time when the surface reflection signal exceeds a predetermined threshold. The reason for determining the detection time based on the maximum value or the threshold value of the surface reflection signal as described above is that the false detection operation may occur due to noise when detecting only the occurrence time of the surface reflection signal.

In the surface reflection signal detection time storing process (S410), the time when the surface reflection signal is detected is stored in a register.

In the recording surface reflection signal detection process (S412), it is determined whether the recording surface reflection signal has been detected. The time point at which it is determined that the recording surface reflection signal has been detected is, for example, a time at which the maximum value of the focus error signal is detected or a time exceeding a predetermined threshold.

In the recording surface reflection signal detection time storing process (S414), the time when the recording surface reflection signal is detected is stored in a register.

In the CD / DVD determination process (S416), the CD / DVD is determined by using the detected point of time of the surface reflection signal and the point of time of the recording surface reflection signal. Specifically, CD / DVD is determined by comparing the elapsed time from the time of surface reflection signal generation to the time of generation of recording surface reflection signal with the elapsed time corresponding to CD or the elapsed time corresponding to DVD.

If it is determined in the CD / DVD determination process (S416) that it is a DVD, the process branches to the DVD processing process. In the present invention, a detailed description of the DVD process is omitted.

In the LD replacement process (S418), the CD LD is turned off and the DVD LD is turned on.

In the second objective lens down process (S420), while the objective lens is down, the magnitude of the recording surface reflection signal, for example, the peak to peak value of the focus error signal is detected.

In the CD / CDR determination process (S422), the CD / CDR is determined according to the magnitude of the recording surface reflection signal detected in the second object lens down process (S420). In the DVD LD condition, since the CDRs generally have a reflectance of 0 to 10% compared to the CD, the CD / CDR is determined based on the CDRs.

Specifically, if the magnitude of the recording surface reflection signal is less than or equal to the predetermined level, it is determined as a CDR optical disk, otherwise it is determined as a CD.

In the CDR gain setting process (S424), a gain matching the CDR is set.

In the CDRW gain setting process (S426), a gain suitable for the CDRW is set.

The CD / CDRW determination process S212 as shown in FIG. 2 is omitted for simplicity.

In the LD replacement process (S428), the DVD LD is turned off and the CD LD is turned on.

In the second objective lens up process (S430), focus is achieved while the objective lens is up while the CD LD is operated. In addition, the peak to peak value of the focus error signal is detected.

In the process of determining the size of the focus error signal ( S432 ), it is checked whether the size of the focus error signal detected in the second object lens up process (S430) is appropriate.

If the mounted optical disc is a CDR and is normally set to the gain of the CDR, the magnitude of the focus error signal is normal. Also, if the mounted optical disc is a CDRW and is normally set to the gain of the CDRW, the magnitude of the focus error signal is normal.

However, even if the mounted optical disc is a CDR, if the gain of the CDRW is set, the size of the focus error signal is twice as large as that of the normal case.

If it is determined that the size of the focus error signal is larger than normal in the size determination process (S432) of the focus error signal, the gain corresponding to the CDR is set through the CDR gain setting process (S434).

5 to 7 are waveform diagrams shown to schematically illustrate the method shown in FIG. 4.

5 is a waveform diagram showing a surface reflection signal and a focus error signal seen in the case of a CDR. In FIG. 5, the lower triangular wave signal shows an actuator driving signal for controlling up / down of the objective lens, and the upper signal shows a surface reflection signal.

When the actuator drive signal increases, the objective lens is up, and when it decreases, it is down.

In FIG. 5, when the CD LD operates and the actuator driving signal increases, the section 1 (the objective lens is up), the surface reflection signal s is generated at time t1 and the focus error signal f is generated at time t2.

The magnitude of the surface reflection signal s is about 0.5Vp-p and the focus error signal f is about 3.3Vp-p.

Looking at section 2 (the objective lens is down) where the DVD LD operates and the actuator drive signal decreases, the focus error signal f 'occurs at t3 and the surface reflection signal s' occurs at t4.

The focus error signal f 'is about 3.0Vp-p and the surface reflection signal s' is about 0.5Vp-p. This is because the reflectance of the CD-based optical disc is about 70-80% under the DVD LD condition.

Looking at section 3 where the CD LD operates, the gain is set for the CD, and the actuator drive signal increases, the surface reflection signal s '' occurs at t5 and the recording surface reflection signal f '' at t6.

The magnitude of the surface reflection signal s " is about 0.5 Vp-p or less and very small, and the magnitude of the focus error signal f " is about 1.2 to 1.3 Vp-p, which is a normal value.

The level of the surface reflection signal and the focus error signal are different when compared with the interval 1 which is the same CD LD condition. This is because the gain of the focus error signal is set to the maximum in order to facilitate the detection of the surface reflection signal in section 1, and the gain suitable for the CD in section 3.

6 is a waveform diagram showing a surface reflection signal and a focus error signal seen in the case of a CDR.

Referring to section 1 in which the CD LD operates and the actuator driving signal increases in FIG. 6, the surface reflection signal s occurs at a time t1 and a focus error signal f occurs at a time t2.

The magnitude of the surface reflection signal s is about 0.5Vp-p and the focus error signal f is about 3.3Vp-p. Looking at section 2 where the DVD LD operates and the actuator drive signal decreases, the focus error signal s 'occurs at time t3 and the surface reflection signal f' occurs at time t4.

It can be seen that the focus error signal s 'is about 0.2 Vp-p and the surface reflection signal f' is about 0.5 Vp-p, which is very small. This is because, in the case of CDR, the reflectance becomes almost zero under DVD LD.

Looking at section 3 where the CD LD operates, the gain is set for the CDR, and the actuator drive signal increases, the surface reflection signal s '' occurs at t5 and the focus error signal f '' at t6.

The magnitude of the surface reflection signal s " is about 0.5 Vp-p or less and very small, and the magnitude of the focus error signal f " is about 1.2 to 1.3 Vp-p, which is a normal value.

The level of the surface reflection signal and the focus error signal are different when compared with the interval 1 which is the same CD LD condition. This is because the gain of the focus error signal is set to the maximum in order to facilitate the detection of the surface reflection signal in the section 1, and the gain suitable for the CDR in the section 3 is set.

Fig. 7 is a waveform diagram showing a surface reflection signal and a focus error signal seen when the mounted optical disc is a CDR but it is incorrectly determined to be a CDRW.

Referring to section 1 in which the CD LD operates and the actuator driving signal increases in FIG. 7, the surface reflection signal s occurs at time t1 and the focus error signal f occurs at time t2.

The magnitude of the surface reflection signal s is about 0.5Vp-p and the focus error signal f is about 3.3Vp-p.

Looking at the interval 2 where the DVD LD operates and the actuator driving signal decreases, the focus error signal f 'is generated at time t3 and the surface reflection signal s' is generated at time t4.

The focus error signal f 'is about 1 Vp-p and the surface reflection signal s' is about 0.3 Vp-p. This is because the reflectance decreases under the DVD LD in the case of the CDRW optical disc.

Looking at section 3 where the CD LD operates, gain is set for the CDRW, and the actuator drive signal increases, a surface reflection signal s '' occurs at t5 and a focus error signal f '' at t6.

The magnitude of the surface reflection signal s " is about 0.5 Vp-p or less, which is very small and the focus error signal f " is about 3 Vp-p, which is larger than normal.

This is because the gain of the CDRW is larger than the gain of the CDR. Therefore, it can be seen that the CDR is incorrectly recognized as CDRW because the size of the focus error signal is larger than normal.

As described above, the optical disc determination method according to the present invention improves the adaptability of the CD / DVD-compatible optical disc player by determining the CD / DVD using the difference in the elapsed time from when the surface reflection signal is generated to the time when the recording surface reflection signal is generated. Has an effect.

In addition, by distinguishing the CDR by using the difference between the reflectance for the CD LD and the reflectance for the DVD LD, it has an effect of increasing the coping force for the CDR optical disk.

Claims (11)

In the method of determining the type of optical disc mounted in the optical disc player corresponding to CD / CDR / CDRW / DVD, (a) detecting the elapsed time from the time when the surface reflection signal is generated to the time when the recording surface reflection signal is generated while changing the focus of the optical signal irradiated on the mounted optical disk; (b) comparing the detected elapsed time with a time corresponding to a CD or a time corresponding to a DVD to determine whether the mounted optical disc is a CD or a DVD; (c) detecting the magnitude of the recording surface reflection signal under a DVD LD condition if it is determined to be CD in step (b); And and (d) determining CD / CDR based on the magnitude of the recording surface reflection signal. delete The method of claim 1, (e) if it is determined in step (d) that the CD is a CD, detecting the magnitude of the recording surface reflection signal under the CD LD condition, and determining the CD / CDRW based on the magnitude of the recording surface reflection signal. Type judgment method. The method of claim 3, (f) if it is determined in step (e) that it is a CDRW, setting a gain suitable for the CDRW and determining whether the magnitude of the recording surface reflection signal is within a normal range under a CD LD condition; and (g) determining if the size of the recording surface reflection signal is not within the normal range in step (f). delete delete delete delete delete delete delete

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