KR100696757B1 - Apparatus and method for calculating betta value of optimum power control - Google Patents

Abstract

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for detecting an optimal recording power of an optical recording medium and an optimal recording power detection method. More particularly, the present invention relates to an apparatus and a method for accurately detecting a beta value necessary for optimal power detection.

The present invention does not measure the highest value (A1) and the lowest value (A2) of the detected high frequency signal, respectively, when measuring the beta value for optimal recording optical power detection in the optical recording medium, A1 + A2, An apparatus and method for optimally recording optical power detection of an optical recording medium, which have an arithmetic means for directly calculating and calculating the values of A1-A2, thereby reducing errors and improving accuracy in stepwise measurements.

Optical record carrier, optical disc, OPC, beta

Description

Optimal Recording Power Detection Apparatus and Method in Optical Recording Apparatus {APPARATUS AND METHOD FOR CALCULATING BETTA VALUE OF OPTIMUM POWER CONTROL}

1 shows a layout of a recordable optical disc;

2 is a diagram showing a relationship between a high frequency signal waveform and a beta value detected when recording and reproducing PCA test data during an OPC process.

Figure 3 shows an embodiment of the A1 + A2 detection circuit in the present invention.

Figure 4 shows an embodiment of the A1-A2 detection circuit in the present invention.

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for detecting an optimal recording power of an optical recording medium and an optimal recording power detection method. More particularly, the present invention relates to an apparatus and a method for accurately detecting a beta value necessary for optimal power detection.

Optical discs are disc media that have begun to become more common as CDs have become widespread, and are expected in recent years due to the emergence of large-capacity DVDs. In general, optical discs are repetitive discs, such as CD-ROMs, DVD-ROMs, and the like, CD-Rs, DVD-Rs, and other write-only discs, such as CD-RWs and DVD-RAMs. It can be classified as a recordable disc.

The optical recording / reproducing apparatus records an information on an optical disc by irradiating a light beam of relatively large energy that can change the physical characteristics of the information recording layer, and uses an optical disc of small energy that does not change the physical characteristics of the information recording layer. Play back information from. To this end, an optical recording / reproducing apparatus typically drives a laser diode at a relatively high recording power to perform optical recording during recording using a laser diode. Such an optical recording / reproducing apparatus inevitably performs an Optimal Power Control (OPC) process for selecting a recording power suitable for a disc when information is recorded on a recordable optical disc. For the OPC, the recordable optical disc has a PCA, which is a test area for determining recording power, in an unused area of the innermost circumference.

Referring to Fig. 1, a layout of a recording area of a recordable optical disc is shown. Referring to Fig. 1, a recordable optical disc is divided into a clamping area 10 clamped by a clamper and a recording area 20 in which data is recorded and reproduced.

The recording area 20 includes a PCA 22 which is used as a test area when performing OPC in the radial direction, a PMA 24 in which the head address of a track in which data is recorded in the user data area 26, and the like. An in area 26, a user data area 28 in which user data is recorded, and a lead-out area 30 located at the outermost circumference. Here, the PCA 22 is divided into a test area 22A in which test data is recorded when performing OPC, and a count area capable of counting the number of OPC executions, that is, the number of repeated recordings.                         

The optical recording / reproducing apparatus records and reproduces test data on the PCA 22 of the optical disc 10 described above, detects a reproduction signal (i.e., a high frequency signal) proportional to the amount of reflected light, and detects the up and down symmetry of the high frequency signal waveform. The corresponding parameter, i.e., beta beta) value is calculated and selected as the optimal recording power adjusted to keep the beta value constant, and the data to be recorded is recorded on the disc in accordance with the file structure. In this case, the recording power may vary due to factors such as the recording sensitivity of the disk film, the temperature, the change of the recording sensitivity due to the variation of the laser wavelength, and the like.

Referring to Fig. 2, the relationship between the high frequency signal waveform and the beta value detected when the test data is recorded and reproduced in the PCA in the OPC section is shown.

Each of the high frequency signal waveforms shown in FIG. 2 represents a case where a beta value is smaller than '0', a beta value is '0', and a beta value is larger than '0'. Here, the beta value indicating the up and down asymmetry of the high frequency signal waveform is calculated as follows using the Top Peak A1 and the Bottom Peak A2 based on the zero potential (0 V) of the high frequency signal waveform. Done.

That is, beta (β) = (A1 + A2) / (A1-A2) * 100 [%] (when using single power supply)

The beta value calculated as described above is smaller than '0' when the high frequency waveform has the lowest value A2 greater than the highest value A1, and the beta value is '0' when the high frequency waveform has the same maximum value A1 and the lowest value A2. It can be seen that the beta value is larger than '0' in the case of a high frequency waveform which is equal to ', and the minimum value A2 is smaller than the maximum value A1. Here, the recording power is adjusted to satisfy the case where the beta value is equal to '0' (target beta) to determine the optimal recording power. Meanwhile, the beta value may also be calculated as beta (β) = (A1 + A2-2VC) / (A1-A2) * 100 [%] (when using a positive power supply).

However, when measuring the levels of A1 and A2 of the AC-coupled HF signal in order to measure the beta values as described above, and calculating the beta values using the measured values, the fluctuation of the A1 and A2 levels is small according to the beta change. However, the sensitivity of the measured beta data is less reliable because of its sensitivity to noise levels, and many errors occur.

In addition, since the A1 and A2 signals deviate much from the reference level VC up and down, the amplification cannot be sufficiently performed.

The present invention does not measure the highest value (A1) and the lowest value (A2) of the detected high frequency signal, respectively, when measuring the beta value for optimal recording optical power detection in the optical recording medium, A1 + A2, An apparatus and method for optimally recording optical power detection of an optical recording medium, which have an arithmetic means for directly calculating and calculating the values of A1-A2, thereby reducing errors and improving accuracy in stepwise measurements.

An apparatus for detecting an optimal recording power of an optical recording medium according to the present invention includes: means for reproducing a high frequency signal from an optical recording medium for setting an optimum recording power, and a first outputting operation for calculating the sum of the highest and lowest values of the reproduced high frequency signal. OPC is performed by measuring a beta value using a calculation means, a second calculation means for calculating a difference value between the highest value and the lowest value of the reproduced high frequency signal, and a value output from the first calculation means and the second calculation means. It characterized in that it comprises a control means to.

The apparatus for detecting optimal recording power of the optical recording medium according to the present invention further includes means for reproducing a high frequency signal from the optical recording medium for setting the optimum recording power, and calculating and outputting a sum value of the highest value and the lowest value of the reproduced high frequency signal. And means for controlling OPC by measuring beta values using the values output from the calculation means and the measured highest and lowest values.

In addition, the optimal recording power detection method of the optical recording medium of the present invention comprises the steps of reproducing a high frequency signal from the optical recording medium to set the optimum recording power, and a factor for measuring beta using the highest and lowest values of the reproduced high frequency signal And a step of measuring the beta value using the converted factor for the beta measurement.

In the method of detecting the optimal recording power of the optical recording medium of the present invention, the factor for measuring beta is characterized by outputting A1 + A2 with respect to the highest value A1 and the lowest value A2 of the high frequency signal.

In the method of detecting the optimal recording power of the optical recording medium of the present invention, the factor for measuring beta is characterized by outputting A1 + A2 and A1-A2 with respect to the highest value A1 and the lowest value A2 of the high frequency signal. .

Fig. 3 is a circuit diagram showing an embodiment of the A1 + A2 detection circuit in the optimum recording optical power detection apparatus for the optical recording medium according to the present invention, and Fig. 4 is a circuit diagram showing an embodiment of the A1-A2 detection circuit. The f (A1 + A2) values and the f (A1-A2) values calculated by the detection circuits of FIGS. 3 and 4 are input to the beta measuring means for performing OPC, not shown, so that the beta measurement using the above values is performed. do.

First, the A1 + A2 detection operation will be described with reference to FIG.

As already described in the prior art, the A1 and A2 signals deviate much from the reference level VC up and down, and thus cannot sufficiently amplify. Due to this, the beta value is lacking in accuracy due to the influence of noise when measuring the A1 and A2 levels. However, the present invention does not use each factor (A1 level, A2 level) necessary for measuring the beta value separately, and uses a value converted into one value (A1 + A2, A1-A2) to calculate the beta value. By measuring, the influence of noise can be reduced and the accuracy and reliability of the measured beta values can be increased.

That is, according to Fig. 3, since the average signal (A1 + A2) / 2 of the signals A1 and A2 is near the reference signal level VC, the amplification can be made sufficient, so that the influence of noise can be reduced. will be.

Referring to FIG. 3, an A1 + A2 detection circuit includes an operational amplifier OP1 for calculating f (A1 + A2) for the highest value A1 and the lowest value A2 of a reproduction high frequency signal, and the operational amplifier. Resistor R1, R2 (R1 = R2) for inputting 1/2 of A1 and A2 values to the input terminal (+) of OP1 and inputting the amplification gain of the operational amplifier OP1. It includes the resistor (R3, R4) (R4 / R3 = a) for setting based on.

In Fig. 3, the values A1 and A2 are added through the resistors R1 and R2, respectively, and are input to the non-inverting input terminal (+) of the operational amplifier OP1, and the operational amplifier OP1 receives the input A1 and A2 signal values. The amplification operation is performed according to the gain a of the gain setting resistors R3 and R4 based on the reference level VC to output the amplification operation.

That is, under the condition of R1 = R2 and R4 / R3 = a, the output X of the operational amplifier OP1 outputs the converted values for the inputs A1 and A2 as follows.

X = (a + 1) / 2 * (A1 + A1) -a * VC = (a + 1) / 2 * [(A1 + A2) -2 * VC] + VC

4 is a circuit diagram showing an embodiment of the A1-A2 detection circuit in the optimum recording optical power detection apparatus for the optical recording medium according to the present invention, wherein the f (A1-A2) value calculated and output by this A1-A2 detection circuit. Is input to the beta measurement means for performing OPC not shown, and the beta measurement using the above values is performed.

Although the A1-A2 detection circuit of FIG. 4 cannot amplify as much as the A1 + A2 detection circuit, it can amplify more than A1.

Referring to FIG. 4, the A1-A2 detection circuit according to the present invention includes an operational amplifier OP2 for calculating f (A1-A2) for the highest value A1 and the lowest value A2 of a reproduction high frequency signal, and the operational amplifier. The resistors R5 and R6 (R5 = R6) for inputting the A1 and A2 values to the input terminals (+) (-) of the OP2 and the amplification gain of the operational amplifier OP1 are referred to as reference levels VC. Resistors R7 and R8 (R7 = R8) (R7 / R5 = b) for setting on the basis.

In Fig. 4, the values A1 and A2 are added through the resistors R5 and R6, respectively, and are input to the non-inverting input terminal (+) and the inverting input terminal (-) of the operational amplifier OP2, and the operational amplifier OP2 is input. The A1 and A2 signal values are amplified and output according to the gain b of the gain setting resistor based on the reference level VC.

That is, under the condition of R5 = R6, R7 = R8 and R7 / R5 = b, the output Y of the operational amplifier OP2 outputs the converted values for the inputs A1 and A2 as follows.

Y = b * (A1-A2).

In the present invention, both A1 + A2 and A1-A2 values converted into one value by the calculation means of Figs. 3 and 4 are used for beta measurement, or only A1 + A2 detection circuit is used and A1-A2 Levels can also beta by measuring A1 and A2 levels.

The beta calculation in the case of using the A1 + A2 and A1-A2 detection circuits described above may be performed as follows.

Beta = (A1 + A2-2 * VC) / (A1-A2) * 100 [%]

     = (X-VC) / Y * (b / (a + 1)) * 100 [%] (in this case, using both A1 + A2 and A1-A2 detection circuits).

That is, in this case, one value (A1 + A2) is not calculated separately using factor (A1 + A2) and (A1-A2) detection circuits of FIGS. 3 and 4 without separately calculating factors A1 and A2 for beta measurement. In this case, beta calculation is performed in terms of A1-A2).

Or beta = (X-VC) / (A1-A2) * (1 / (a + 1)) * 100 [%], in this case using only the A1 + A2 detection circuit.

That is, in this case, only the detection circuit (A1 + A2) of Fig. 3 is used. In this case, the values A1-A2 are obtained by measuring the levels A1 and A2, and the value A1 + A2 is determined using the detection circuit of Fig. 3. This is the case where beta calculation is performed by converting one value (A1 + A2).

In the beta measurement for setting the optimal recording power value of the optical recording medium, the present invention does not use each factor (the highest value A1 and the lowest value A2) of the HF signal separately for calculation, and uses one value A1 +. It measures using A2) and the value converted into (A1-A2).

Therefore, the amplification of the information for beta calculation is easy, and the accurate beta value can be calculated therefrom, thereby increasing the reliability of the optimum recording optical power control, and accurately calculating the optimized recording optical power value and using it for data recording.

Claims (7)

Means for reproducing a high frequency signal from an optical recording medium for setting an optimum recording power, first calculating means for calculating and outputting a sum value of a maximum value and a minimum value of the reproduced high frequency signal, and a maximum value and a minimum value of the reproduced high frequency signal. And second control means for calculating and outputting a difference value, and control means for performing OPC by measuring a beta value using the values output from the first and second calculation means. Optimal recording power detection device. Means for reproducing a high frequency signal from an optical recording medium for setting an optimum recording power, computing means for calculating and outputting a sum value of the highest value and the lowest value of the reproduced high frequency signal, the value output from the calculating means and the measured maximum value, And a control means for performing an OPC by measuring a beta value using the lowest value. 3. The apparatus according to claim 1 or 2, wherein the sum value calculating means of the highest value A1 and the lowest value A2 of the reproduction high frequency signal; An operational amplifier for f (A1 + A2) operation on the highest value A1 and the lowest value A2 of the reproduction high frequency signal, and the resistors R1, R2) (R1 = R2) and resistors R3 and R4 (R4 / R3 = a) for setting the amplification gain of the operational amplifier based on the reference level VC. Optimum recording power detection device in recording device. 2. The apparatus according to claim 1, wherein the difference value calculating means of the highest value A1 and the lowest value A2 of the reproduction high frequency signal; An operational amplifier for f (A1-A2) operation on the highest value A1 and the lowest value A2 of the reproduction high frequency signal, and resistors R5 and R6 for inputting A1 and A2 values to the input terminals of the operational amplifier, respectively ( R5 = R6, and resistors R7 and R8 (R7 = R8) (R7 / R5 = b) for setting the amplification gain of the operational amplifier based on the reference level VC. The optimal recording power detection device in the optical recording device. Reproducing a high frequency signal from an optical recording medium for setting an optimum recording power, converting and outputting a factor for beta measurement using the highest and lowest values of the reproduced high frequency signal, and converting the factor converted for the beta measurement And measuring the beta value by using the optical recording medium. 6. The method according to claim 5, wherein the factor for measuring beta outputs A1 + A2 in terms of A1 and A2 of the high frequency signal. 6. The optimal recording power detection of an optical recording medium according to claim 5, wherein the factor for measuring beta outputs A1 + A2 and A1-A2 in terms of A1 and A2 of the high frequency signal. Way.

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