JP2003248924A - Device and method to calculate optical recording medium performance data - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a device and method that can correctly calculate the data showing the performance of an optical recording medium by using signals read from narrow regions like embossed regions on an optical recording medium. <P>SOLUTION: At least, a track is sequentially designated from a plurality of tracks in the specified narrow regions consisting of many tracks in a recording area of an optical recording medium. Each track thus specified is read repeatedly, and the specified parameters are measured depending on the read signals to obtain tentative measurements. When specified tentative measurements are obtained for a plurality of tracks, the specified parameter measurements are decided for calculating the performance data using those tentative measurements. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a performance data calculation device and method for calculating performance data indicating the performance of an optical recording medium.

[0002]

2. Description of the Related Art Currently, CD-Rs, CD-RWs, and DVDs are used as optical recording disks capable of writing information data.
-R, DVD-RW, DVD-RAM, etc. are known. Furthermore, an information recording / reproducing apparatus for recording and reproducing information data on such a recording disc has been commercialized.

FIG. 1 shows a DVD as the recording disk.
It is a figure which shows the area | region structure of -RW roughly. As shown in FIG. 1, a DVD-RW is a PCA (Power Calibration Area), RMA (Rec
ording management area), a lead-in area, a data area, and a lead-out area. PCA is an area for performing trial writing when determining the recording power of the laser beam, and RMA is an area for writing management information regarding recording. Part of the lead-in area (control data zone) is an embossed area. In this embossed area, the track is formed by phase pits.

FIG. 2 is a view showing a part of the recording surface of such a recordable disc. As shown in FIG. 2, on the disk substrate 101, a convex groove track 103 and a concave land track 102 in which information pits Pt carrying information data are to be formed spirally or concentrically.
Are formed alternately. Further, a plurality of LPPs (land prepits) 104 are formed between the groove tracks 103 adjacent to each other. The LPP 104 is provided in advance on the land track 102 in order to know the recording timing and address when the disc recorder records the information data.

A disc player for reproducing an optical disc having such an LPP is provided with an LPP detection circuit. The LPP detection circuit is composed of a binarization circuit, and the reflected beam from the optical disk is received by the pickup by, for example, a photodetector divided into two in the track tangential direction, and a difference signal of the output signals of the photodetector, that is, a radial signal. The push-pull signal PP is obtained. Push-pull signal PP
Has a waveform as shown in FIG. 3, and the LPP component is a component protruding from the push-pull signal PP. Therefore, by comparing the level of the push-pull signal PP with the threshold value TH, the pre-pit detection signal P indicating the detection of LPP is obtained.
To generate a P _D.

The level of the pre-pit detection signal PP _D changes like a pulse as shown in FIG. 4 at each reading position of the pickup corresponding to the LPP. Pre-pit detection signal P
In P _D , there is a synchronizing pulse P _SYNC that appears every period T as shown in FIG. Following the synchronization pulse P _SYNC , there are two pre-data pulses at a predetermined interval, but they do not always exist in each cycle to represent data such as an address. As shown in FIG. 4, the pulse at the third position from the synchronization pulse P _SYNC is the pre-data pulse P _D carrying the information data relating to the address and recording. When recording information on the optical disc, this pre-pit detection signal PP
Information is recorded by detecting the record information such as the address of the optical disc and the write strategy based on _D.

Manufacturers of optical discs containing LPP are required to have the LPP of the produced optical discs satisfy the standards. In order to determine that the optical disc meets the standards, AR (Aperture Ra
tio) The measurement is performed. In the AR measurement, the LPP component of the push-pull signal PP (the third LPP position portion after the LPP for synchronization is the first LPP) is repeatedly sampled for a predetermined period. By this sampling, the overlapping waveform of the push-pull signal PP of the third LPP portion, that is, the pre-pit waveform is as shown in FIG.
It is displayed on a display device such as an oscilloscope. For this display, the LPP for synchronization is used to trigger the third L
The delay time is manually adjusted so that the PP is located at the center of the screen of the display device.

The maximum value APmax and the minimum value APmin of the peak value from the maximum value WOmax of the groove track component in the displayed push-pull signal PP are detected and AR
It is necessary to calculate the value as a standard expression, AR = APmin / APmax, and confirm that the AR value is not less than the specified value. The large AR value means that the binarizable range is wide and the detection accuracy of the pre-pit detection is high.

[0009]

The target area for determining that the optical disk is manufactured in conformity with the standard is not limited to the data area of the optical disk, but also the embossed area in the information area. However, the embossed area is very narrow, and it is difficult to detect the pre-pit waveform required for calculating the AR value with high accuracy simply by reproducing the embossed area continuously.

This problem is the same when the carrier level and the noise level of the wobble signal obtained from the read signal in the embossed area of the optical disc are measured to calculate the data indicating the performance of the optical recording medium such as the CN ratio. . Therefore, an object of the present invention is to provide an optical recording medium performance data calculating apparatus and method capable of accurately calculating data indicating the performance of an optical recording medium based on a read signal in a narrow area such as an embossed area of the optical recording medium. Is to provide.

[0011]

A performance data calculating apparatus of the present invention measures at least one predetermined parameter for a predetermined narrow area consisting of a plurality of tracks in a recording area of an optical recording medium, and measures the predetermined parameter. Is a performance data calculation device for calculating performance data indicating the performance of the optical recording medium according to the measured value of the parameter of, and at least one track is sequentially specified from a plurality of tracks in a predetermined narrow area. Reading means for repeatedly reading one track designated by the designating means, measuring means for measuring a predetermined parameter based on a read signal from the reading means to obtain a provisional measurement value, and for each of the plurality of tracks. When the provisional measurement value of the predetermined parameter of is obtained, the performance of the measurement value of the predetermined parameter according to each provisional measurement value It is characterized by comprising determination means for determining for the calculation of the over data, the.

The performance data calculating method of the present invention measures at least one predetermined parameter for a predetermined narrow area consisting of a plurality of tracks in a recording area of an optical recording medium, and uses it as a measured value of the predetermined parameter. A method for calculating performance data indicating the performance of an optical recording medium according to the method, comprising: a track specifying step of sequentially specifying at least one track from a plurality of tracks in a predetermined narrow area; A reading step for repeatedly reading the specified one track; a measuring step for measuring a predetermined parameter based on a signal read from the one track designated by the reading step to obtain a provisional measurement value; and a plurality of tracks. When the provisional measurement values of the prescribed parameters for each are obtained, the provisional measurement values A determining step of determining for the calculation of the performance data measurements for a given parameter depending,
It is characterized by having.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will now be described in detail with reference to the drawings. FIG. 6 shows a pre-pit waveform measuring device as a performance data calculating device of the present invention. This pre-pit waveform measuring apparatus is provided with a recording / reproducing head 2 capable of writing and reading information on an optical disc 1 (for example, DVD-RW) to be inspected. The recording / reproducing head 2 has a recording beam light generator (not shown) for recording information data on the write-once or rewritable optical disc 1 having a recording surface as shown in FIG. A reading beam light generator (not shown) for reading information data and a four-division photodetector (reference numeral 20 in FIG. 7) are mounted.

It is not necessary to separately provide the recording beam light generator and the reading beam light generator, and it is one light beam generator that generates the recording light beam during recording and generates the reading light beam during reading. May be. The reading beam light generator irradiates the optical disc 1 rotated by the spindle motor 9 with the reading beam light to form an information reading spot on the recording surface thereof. 4-split photodetector 20
Is the direction along the tangent line of the information recording track (groove track 103) of the optical disc 1, as shown in FIG.
It is composed of a photoelectric conversion element having light receiving surfaces 20a to 20d divided into four by a direction orthogonal to the tangent line of the recording track. The photoelectric conversion element receives the reflected light from the optical disc 1 due to the information reading spot by each of the four light receiving surfaces 20a to 20d, and individually outputs each as an electric signal and outputs it as light receiving signals Ra to Rd.

The servo control device 4 receives these received light signals Ra.
A focus error signal, a tracking error signal, and a slider drive signal are generated based on Rd to Rd. The focus error signal is supplied to a focusing actuator (not shown) mounted on the recording / reproducing head 2. The focusing actuator adjusts the focus of the information reading spot based on the focus error signal. The tracking error signal is a tracking actuator (not shown) mounted on the recording / reproducing head 2.
Is supplied to. The tracking actuator adjusts the formation position of the information reading spot in the disk radial direction based on the tracking error signal. The slider drive signal is supplied to the slider 10. The slider 10 moves the recording / reproducing head 2 in the disk radial direction at a speed according to the slider drive signal.

A track jump pulse generation circuit 40 is connected to the servo control device 4. The track jump pulse generation circuit 40 is a personal computer 6 described later.
A track jump pulse is generated in response to the track jump command from 2. The reading or writing position of the optical disk 1 by the recording / reproducing head 2 is moved inward by one track by the operation of the tracking servo system of the servo control device 4 in response to the track jump pulse.

The received light signals Ra to Rd are added to the adder 2
1 to 23 and a head amplifier 25 having a subtractor 24. The adder 21 adds the received light signals Ra and Rd,
The adder 22 adds the received light signals Rb and Rc. That is, the adder 21 adds the received light signals Ra and Rd received by the light receiving surfaces 20a and 20d of the four-division photodetector 20, respectively, and outputs the added received light signal Ra _{+ d} . The adder 22 adds the received light signals Rb and Rc received by the light receiving surfaces 20b and 20c of the four-division photodetector 20 and outputs the added received light signal Rb _{+ c} .

The adder 23 adds the output signals R _{a + d} and R _{b + c} of the adders 21 and 22. The output signal of the adder 23 is a read signal, that is, an RF signal, and is supplied to the information data reproducing circuit 30. The information data reproducing circuit 30 binarizes the read signal, and then sequentially executes demodulation processing, error correction processing, and various information decoding processing, so that the information data (video data, audio data) recorded on the optical disc 1 is processed. (Data, computer data) is reproduced and output.

The subtractor 24 outputs the output signal R _{a + d} of the adder 21.
From which the output signal R _{b + c} of the adder 22 is subtracted. Subtractor 2
The output signal of No. 4 becomes a signal indicating the frequency due to the wobbling of the track 103, and is supplied to the spindle servo device 26 of the spindle motor 9. The spindle servo device 26 rotationally drives the spindle motor 9 so that the frequency obtained from the output signal of the subtractor 24 becomes a frequency corresponding to a predetermined rotation speed. The configuration of the spindle servo device 26 is disclosed in JP-A-10-283638.
Since it has already been disclosed in the publication, the description thereof will be omitted here.

The pre-pit detection circuit 5 includes adders 21, 2
As shown in FIG. 2, the land prepit (LPP) 104 formed on the land track (prepit track) 102 of the optical disc 1 is detected based on the respective output signals of No. 2 and the prepit detection signal PP _D is obtained. It is supplied to the recording processing circuit 7. The recording processing circuit 7 uses the pre-pit detection signal PP _D.
On the basis of the above, the position at which the recording / reproducing head 2 is currently recording, that is, the position on the groove track 103 is recognized, and a control signal for causing the recording / reproducing head 2 to make a track jump from that position to a desired position is sent. Supply to the servo control device 4. Further, the recording processing circuit 7
A desired recording modulation process is performed on the information data to be recorded (inspection information data) to generate a recording modulation data signal, which is supplied to the recording / reproducing head 2. The recording beam light generator mounted on the recording / reproducing head 2 generates recording beam light according to the recording modulation data signal, and irradiates it on the groove track 103 on the optical disc 1. At this time, heat is transmitted to the area on the groove track 103 irradiated with the recording beam, and information pits (marks) are formed in the area.

The structure of the recording processing circuit 7 is also disclosed in Japanese Patent Laid-Open No.
Since it has already been disclosed in Japanese Patent Application Laid-Open No. 0-283638, further description will be omitted here. As shown in FIG. 7, the pre-pit detection circuit 5 outputs the output signal _{Ra + d} of the adder 21.
And an output signal R _{b + c of the} adder 22
An amplifier 32 that amplifies the output signal, a subtracter 33 that subtracts the output signal of the amplifier 32 from the output signal of the amplifier 31 and outputs the result as a radial push-pull signal (groove wobble signal) PP, and an output push-pull signal PP of the subtractor 33. It is composed of a binarizing circuit 34 which binarizes with the threshold value TH to generate the pre-pit detection signal PP _D , an AND circuit 50, and a gate pulse generating circuit 51. The gain G1 of the amplifier 31 and the gain G2 of the amplifier 32 are set to G1 = G2.

The push-pull signal output from the subtractor 33
The number PP is the LPP interval detection circuit 60 and the oscilloscope 6
1 is supplied. The output signal of the binarization circuit 34
Pit detection signal PP_DWill be described later via the AND circuit 50.
Supplied to a personal computer (personal computer) 62
It In addition to the binarization circuit 34 described above, the AND circuit 50 has a gate.
A pulse pulse generation circuit 51 is connected. Gate pal
The scanning circuit 51 is for the embossed area of the optical disc 1.
Command from personal computer 62 during AR measurement period
A gate pulse is generated according to the. AND circuit 50 is 2
Pre-pit detection signal PP from the digitizing circuit 34 _DThe person
The gate pulse is being supplied to the null computer 62
To stop.

As shown in FIG. 7, the LPP interval detection circuit 60 comprises a comparator 71, a divide-by-4 circuit 72, and a counter 73. The comparator 71 has a push-pull signal PP and a wobble slice signal Wslice (reference level).
And a binary wobble signal is generated. The divide-by-4 circuit 72 divides the binary wobble signal by four. Counter 73
Detects the period of the binarized wobble signal by counting the pulses of the clock signal. The frequency of the clock signal is sufficiently higher than the frequency of the push-pull signal PP. The counting result of the counter 73 is supplied to the personal computer 62 as the LPP interval.

The personal computer 62 generates the above-mentioned track jump command to the track jump pulse generating circuit 40 when measuring the AR of the embossed area of the optical disk 1. During the AR measurement period, the track jump command is repeatedly generated in synchronization with the rotation of the spindle motor 9 in order to repeatedly reproduce one track in the embossed area of the optical disc 1.

The oscilloscope 61 has a push-pull signal P
For example, P is sampled to display a portion corresponding to LPP in the push-pull signal PP. A personal computer (hereinafter referred to as a personal computer) 62 is connected to the oscilloscope 61. The personal computer 62 uses the level data of the push-pull signal PP stored in the internal memory of the oscilloscope 61 (for example, a sample memory 93 described later) and the LPP interval detection value by the LPP interval detection circuit 60 to calculate a delay time described below. Although not specifically shown, the personal computer 62 includes at least a CPU and an internal memory.

The connection between the personal computer 62 and the oscilloscope 61 is based on the interface standard such as GPIB, 10BASE-T or RS-232C. The signal (pre-pit detection signal PP _D ) output from the binarization circuit 34 is supplied to an error rate detection circuit (not shown), and the error rate according to the supplied signal is detected there.

The oscilloscope 61 can have the configuration shown in FIG. 8, for example. That is, the oscilloscope 61 includes an A / D converter 91, a control circuit 92, a sample memory 93, a display memory 94, X and Y drivers 95 and 96, a display panel 97, an operation unit 98, and an interface 99. It has and. The A / D converter 91 converts an input analog signal into a digital signal. The control circuit 92 sequentially writes the sample data of the digital signal obtained by the A / D converter 91 to the sample memory 93, reads the data to be displayed from the sample memory 93, writes the data to be displayed in the display memory 94, and expands it. The display memory 94 has a storage position corresponding to each pixel of the display panel 97. The X and Y drivers 95 and 96 drive the display panel 97 in accordance with the data written in the display memory 94 to display the waveform of the input analog signal on the display panel 97. The interface 99 is, for example, GPIB, 10BASE-T, for connecting with the personal computer 62.
Alternatively, it is a circuit based on an interface standard such as RS-232C and transfers the data written in the sample memory 93 to the personal computer 62 via the control circuit 92.
Further, the interface 99 relays the command from the personal computer 62 to the control circuit 92.

In the pre-pit waveform measuring apparatus having such a configuration, the push-pull signal PP output from the subtractor 33
In the case of the optical disc 1, as shown in FIG. 9A by the wobbling groove 103 as shown in FIG. 2, it is a sine waveform (correctly a waveform very similar to the sine waveform. (Referred to as a waveform). Further, as shown in FIG. 9A, the portion of the push-pull signal PP corresponding to LPP, that is, the LPP component largely protrudes from the sine waveform to the negative side and exceeds the threshold TH. Figure 9
The two LPP components shown in (a) correspond to the synchronization LPP and the third LPP from the synchronization LPP. That is, it is the waveform of the push-pull signal PP when the one-cycle portion without the second LPP is read.

The push-pull signal PP is compared with the wobble slice signal Wslice in the comparator 71 of the LPP interval detection circuit 60 and becomes a binarized wobble signal having a waveform as shown in FIG. 9B. The binarized wobble signal is a pulse signal indicating 1 if the push-pull signal PP is at a level higher than the wobble slice signal W slice, and 0 if the push-pull signal PP is at a level equal to or lower than the wobble slice signal W slice. . The binarized wobble signal has a waveform as shown in FIG. 9C by being divided by 4 by the divide-by-4 circuit 72. The period t of the signal divided by 4 is
This corresponds to twice the length of time from the LPP component for synchronization of the push-pull signal PP to the third LPP component. Since the spindle motor 9 rotates the optical disc 1 at a predetermined linear velocity by the servo operation of the spindle servo device, it is assumed that the cycle t of the optical disc 1 is constant.

The period t of the signal divided by 4 is the counter 73.
At the pulse signal of the clock signal. The count value of the counter 73, that is, the cycle t is supplied to the personal computer 62. The personal computer 62 has a counter 73
By calculating t / 2 using the count value t according to
The time from the LPP component for synchronization of the push-pull signal PP to the third LPP component is obtained. The calculated t / 2 is supplied to the oscilloscope 61 as a delay time.

During the operation of calculating the delay time t / 2, the personal computer 62 receives the LP for synchronizing the push-pull signal PP.
The position of the P component is detected. The position of the LPP component for synchronization is determined by comparing the push-pull signal PP with the threshold value TH.
Every time the time point of the P component is detected, it is judged from the LPP component generation interval. What is obtained as the LPP component interval is the time from the synchronization LPP component (first LPP component) to the second LPP component, the time from the second LPP component to the third LPP component, and the synchronization LPP component. 3 from LPP component
Time to the second LPP component, time between the second LPP component and the LPP component for synchronization of the next cycle, the third LPP
Time between PP component and synchronization LPP component of the next cycle, synchronization LPP component to synchronization LPP of the next cycle
The time between ingredients. The time from the LPP component for synchronization to the second LPP component and 3 from the second LPP component
It is the same as the time up to the second LPP component and is the shortest, but otherwise the time is long in the order arranged here. However, compared to the time from the LPP component for synchronization to the second LPP component, the time from the second LPP component to the third LPP component, and the time from the LPP component for synchronization to the third LPP component, respectively. Then, the time from the second LPP component to the LPP component for synchronization of the next cycle, the third LP
The time between the P component and the synchronizing LPP component of the next period and the time between the synchronizing LPP component and the synchronizing LPP component of the next period are sufficiently long. Therefore, one L
When the LPP component is not detected when the predetermined time TA elapses from the time when the PP component is detected, the LPP component generated next is the LPP component for synchronization. Predetermined time TA
Is set to be slightly longer than the above t / 2, for example.

The personal computer 62 generates a trigger signal for the oscilloscope 61. The trigger signal is an external synchronization signal indicating a reference time point on the time axis of the oscilloscope 61.
When generating the trigger signal, the personal computer 62 first determines whether or not it is an AR measurement of the embossed area of the optical disc 1 as shown in FIG. 10 (step S1). In the case of AR measurement of the embossed area of the optical disc 1,
The gate pulse command and the track jump command are generated in synchronization with the rotation of the spindle motor 9 (step S
2). In the case of the AR measurement of the area other than the embossed area of the optical disc 1, the gate pulse command and the track jump command are not generated (step S3).

In the case of the AR measurement of the area other than the embossed area of the optical disk 1, the gate pulse and the track jump pulse are not generated in response to the gate pulse command and the track jump command from the personal computer 62. The output pre-pit detection signal PP _D is directly supplied to the personal computer 62 via the AND circuit 50. On the other hand, in the case of AR measurement of the embossed area of the optical disc 1, a gate pulse is generated from the gate pulse generation circuit 51 in response to a gate pulse command from the personal computer 62,
The pre-pit detection signal PP _D output from the binarization circuit 34 during the generation of the gate pulse is blocked by the AND circuit 50 and is not supplied to the personal computer 62. Also, a personal computer 62
The track jump pulse generation circuit generates a track jump pulse in response to the track jump command from the track jump pulse, and one track in the embossed area of the optical disc 1 is repeatedly reproduced by the track jump pulse.

In addition to the optical disc (for example, DVD-RW version 1.0) in which all of the embossed areas are unrewritable areas, the embossed areas are sequentially read from the inner side of the disk. An optical disk that is an unreadable part (for example, a DVD
There is RW version 1.1). Such DVD-RW
According to version 1.1, the 176 control data blocks located inside the embossed area (called the control data zone) are the readable portions, and the 16 servo blocks that follow it are the unreadable portions. Further, according to the DVD-RW version 1.1 disc, the readable portion is recorded with deep phase pits from which information regarding copy protection and the like can be read, and most discs have LPP between tracks in the readable portion. Not formed. On the other hand, the unreadable portion is formed by shallow phase pits in order to prevent reading of the information overwritten and recorded in the area, and the LPP is formed between the tracks in the unreadable portion like the tracks in the data area. Has been done. The LPP in the unreadable section is provided to access the reading light beam to the data area located immediately after the unreadable section. Therefore, in the case of an optical disc having such a readable portion and an unreadable portion, the unreadable portion is the target of AR measurement of the embossed area.

The personal computer 62, as shown in FIG.
The output signal of the ND circuit 50 is monitored to determine whether or not the prepit detection signal PP _D, which is one LPP component, is generated (step S11). Pre-pit detection signal PP _D
If is generated, time measurement from that point is started (step S12). Then, it is determined whether or not the measured time exceeds the predetermined time TA (step S13).
If the measured time does not exceed the predetermined time TA, step S1
It returns to 1 and determines whether or not a new pre-pit detection signal PP _D is generated. If it is determined in step S11 that the pre-pit detection signal PP _D is not generated, the process proceeds to step S13.

When it is determined in step S13 that the measurement time exceeds the predetermined time TA, it is repeatedly determined whether or not the prepit detection signal PP _D is generated (step S14). When the pre-pit detection signal PP _D is not generated in step S14, it is determined whether the gate pulse is being generated (step S15). As described above, the gate pulse is generated by the gate pulse generation circuit 51 in response to the gate pulse command from the personal computer 62 during the AR measurement of the embossed area. This gate pulse is generated slightly earlier than the track jump pulse (FIG. 12 (a)) as shown in FIG. 12 (b). The time difference between the leading edge of the gate pulse and the leading edge of the track jump pulse corresponds to the time t / 2 from the first LPP to the third LPP. Since the same one track in the embossed area is repeatedly reproduced at the time of AR measurement of the embossed area, tracking is performed at the time of a track jump for moving the reading position (light beam irradiation position) of the optical disk 1 by the recording / reproducing head 2 to the previous track. The error signal produces an S-shaped characteristic as shown in FIG. After the track jump pulse is generated, the gate pulse is substantially generated until the tracking error signal returns to the reference level, that is, until the track jump to the position one track before is completed.

When it is determined in step S15 that the gate pulse is being generated, the time measurement is reset to the initial value (step S16), and the process returns to step S11. Step S1
If it is determined in 5 that the gate pulse is not being generated, the process returns to the determination in step S14. When it is determined in step S14 that the pre-pit detection signal PP _D is generated, the pre-pit detection signal PP _D is L for synchronization.
Since it corresponds to the PP component, the trigger signal is supplied to the oscilloscope 61 (step S17).

The oscilloscope 61 responds to the trigger signal with the delay time t / 2 from the time point as a reference.
The pre-pit waveform is displayed so that the display center is set at the time when the time has passed. The display operation will be described using the configuration of the oscilloscope 61 shown in FIG.
2 receives the trigger signal from the personal computer 62 via the interface 99, the sample data of the digital signal obtained by the A / D converter 91 is transferred to the sample memory 9
Write to 3 sequentially. This needs only the set time from the trigger signal, and this is repeated. On the other hand, the data to be displayed is read from the sample memory 93 and written in the display memory 94 to be expanded. This reading is performed so that the data at the time Tc when the delay time t / 2 has elapsed from the time when the trigger signal was supplied is displayed in the center of the display panel 97. That is, only the sample data for the time width Tc ± nΔt with respect to the time point Tc is repeatedly read for each trigger signal and written in the display memory 94. The number of graduations on the time axis of the display panel 97 is 2n (n is an integer), and the time of one graduation unit is Δt. Since each sample data expanded in the display memory 94 is displayed on the display panel 97 by the X and Y drivers 95 and 96, the pre-pit waveform is displayed at the center of the display panel 97.

AR for the embossed area of the optical disc 1
In the case of measurement, as shown in FIG. 12, the pre-pit detection signal PP _D is not output from the AND circuit 50 during the gate pulse generation period. Therefore, no trigger signal is generated during the gate pulse generation period, and at least a predetermined time T has elapsed since the pre-pit detection signal PP _D was first output from the AND circuit 50 even after the gate pulse disappeared.
If the time A has not elapsed, no trigger signal is generated. As a result, during the track jump period, the push-pull signal PP
12D is disturbed as shown in FIG. 12D, the pre-pit partial waveforms in that period are not superimposed and displayed as noise.

FIG. 13A shows an example in which the pre-pit waveform including the pre-pit detection signal PP _D in the track jump period during the AR measurement for the embossed area is displayed on the display panel 97. In the display waveform of FIG. 13 (a), it is determined that the portion other than the LPP portion of the push-pull signal PP at the time of the track jump is determined to be LPP, and a trigger occurs at a time position other than the synchronization LPP, Three
The component of which the level of the push-pull signal PP other than the th LPP has changed is shown as noise in the pre-pit waveform. FIG. 13B shows an example in which the prepit waveform is displayed on the display panel 97 by ignoring the prepit detection signal PP _D in the track jump period during the AR measurement on the embossed area as described above. In the display waveform of FIG. 13B, the trigger is prevented from occurring at a time position other than the synchronization LPP due to the fluctuation of the push-pull signal PP due to the track jump. The included noise component has been removed.

Next, the operation when the AR value is automatically measured by the personal computer 62 will be described. As shown in FIG. 14, the personal computer 62 first generates a reproduction start command (step S31). In response to the reproduction start command, the servo control device 4 and the spindle servo device 26 start operating to bring the optical disc 1 into a reproducible state. Then, the reading position of the optical disk 1 by the recording / reproducing head 2 is moved to a position immediately before the unreadable portion of the embossed area (step S
32). After moving the reading position, 1 of the unreadable part
Command repeat playback of track (step S3)
3). Repetitive reproduction is performed for one track while the operations of FIGS. 10 and 11 described above are executed in response to the repeated reproduction command.

The personal computer 62 measures the maximum value WOmax of the groove track component (step S34). For example,
The pre-pit waveform formed in the predetermined time TB is sampled at a predetermined timing, the level of each part of the waveform pattern is recognized, and the maximum value WOmax is measured.
When the maximum value WOmax is measured, it is determined whether or not the maximum value WOmax is larger than the memory value X (step S3).
5). The memory value X is the maximum value WOmax stored in the internal memory of the personal computer 62, and the initial value is the maximum value WOmax.
Is a value smaller than the value that can usually be taken as WOmax> X
If the maximum value WOmax at that time is the memory value X
Is stored in the internal memory (step S36), and the process proceeds to the next step S37. In step S35, WOma
If x ≦ X, the process immediately proceeds to step S37.

The personal computer 62 sets L in step S37.
The minimum value LPmin of the PP component is measured. For example, the pre-pit waveform formed in the predetermined time TB is sampled at a predetermined timing, the level of each part of the waveform pattern is recognized, and the minimum value LPmin is measured. When the minimum value LPmin is measured, the minimum value LPmin is the memory value Y.
It is determined whether it is smaller (step S38). The memory value Y is the value of the minimum value LPmin stored in the internal memory of the personal computer 62, and the initial value is a value larger than the value that can normally be taken as the minimum value LPmin. If LPmin <Y, the minimum value LPmin at that time is stored in the internal memory as the memory value Y (step S39), and the process proceeds to the next step S40. If LPmin ≧ Y in step S38, the process immediately proceeds to step S40.

Regarding the measurement of the maximum value WOmax and the minimum value LPmin, Japanese Patent Application No.
No. 1-30107. The personal computer 62 measures the maximum value LPmax of the LPP component in step S40. For example, the pre-pit waveform formed in the predetermined time TB is sampled at a predetermined timing and the maximum value of the pre-pit waveform is directly changed to the maximum value LPmax.
To measure. When the maximum value LPmax is measured, it is determined whether or not the maximum value LPmax is larger than the memory value Z (step S41). The memory value Z is the value of the maximum value LPmax stored in the internal memory of the personal computer 62, and the initial value is a value smaller than the value that can normally be taken as the maximum value LPmax. When LPmax> Z, the maximum value L at that time
Pmax is stored in the internal memory as the memory value Z (step S42), and the process proceeds to the next step S43. Step S
If LPmax ≦ Z at 41, the process immediately proceeds to step S43.

In step S43, the personal computer 62 determines whether or not all the tracks in the unreadable portion of the embossed area have been reproduced. If the unreadable portion of the embossed area is 7 tracks, it is determined whether or not the reproduction of all 7 tracks is completed. When all the tracks in the unreadable portion of the embossed area have not been reproduced, the reading position of the optical disk 1 by the recording / reproducing head 2 is jumped to the next one track (step S).
44). After the track jump, the process proceeds to step S33, the repeated reproduction of the one track after the jump is started, and the above steps S34 to S42 are repeatedly executed.

When all the tracks in the unreadable portion of the embossed area have been reproduced by the determination in step S43, the maximum value WOmax and the minimum value L of the unreadable portion are L.
The Pmin and the maximum value LPmax are finally measured. Therefore, the personal computer 62 calculates the AR value of the embossed area by the following equation (1) (step S45). AR = APmin / APmax = (LPmin-WOmax) / (LPmax-WOmax) (1) Since the prepit waveform from which the noise component at the time of track jump is removed can be obtained as data, the AR value for the embossed area is thus obtained. Is calculated on the personal computer 62, the maximum value APmax and the minimum value A shown in FIG.
The Pmin is not adversely affected by the noise component, and the AR value can be accurately calculated.

The LPP interval detection circuit 60 is not limited to the above-mentioned configuration, and is not limited to the Japanese Patent Application No.
Other configurations of the LPP interval detection circuit shown in No. 01-308868 can also be used in the present invention. Although the above-described embodiments have described the case where the present invention is applied to the calculation of the AR value of the embossed area, the present invention can be applied to the calculation of the CN ratio of the read signal of the embossed area.

Next, the operation when the PC 62 automatically measures the CN ratio of the wobble signal in the embossed area will be described. For automatic measurement of the CN ratio of the wobble signal, a spectrum analyzer 63 is connected to the signal line of the radial push-pull signal (groove wobble signal) PP as shown in FIGS. 6 and 7, and the personal computer 62 operates the spectrum analyzer 63. To control.

The wobble signal is analyzed by the spectrum analyzer 6
When measured by 3, the waveform as shown in FIG. 15 (a) is displayed, for example. In the signal waveform of FIG. 15 (a), carriers exist around a frequency of about 140.6 kHz. The ratio between the carrier level C and the noise level N is calculated as the CN ratio. In the embossed area, the carrier level C fluctuates as shown in FIG. 15B when measured at span zero due to wobbling of the track. The carrier level C becomes the maximum value Cmax when the wobbling of tracks is in the opposite phase relationship between adjacent tracks as shown in FIG. 16 (a), and the wobbling of tracks is adjacent to each other as shown in FIG. 16 (b). When the tracks have the same phase relationship, the minimum value is Cmin.

When the signal waveform of FIG. 15 (a) is displayed on the spectrum analyzer 63 with increased resolution, the signal components in the band near the center frequency are dispersed as shown in FIG. 15 (c). The noise level N is obtained by measuring the level between signal components. As shown in FIG. 17, the personal computer 62 first generates a reproduction start command (step S51).
In response to the reproduction start command, the servo control device 4 and the spindle servo device 26 start operating to bring the optical disc 1 into a reproducible state. Then, the reading position of the optical disc 1 by the recording / reproducing head 2 is moved to the position immediately before the unreadable portion of the embossed area (step S52). After the reading position is moved, the repetitive reproduction of one track of the unreadable portion is instructed (step S53). Repetitive reproduction is performed for one track while the operations of FIGS. 10 and 11 described above are executed in response to the repeated reproduction command.

The personal computer 62 has a maximum carrier level C
max is measured (step S54). For example, the change waveform of the carrier level formed in the predetermined time TC is sampled at a predetermined timing, the level of each part of the waveform pattern is recognized, and the maximum value Cmax is measured.
When the maximum value Cmax is measured, it is determined whether or not the maximum value Cmax is larger than the memory value X (step S55).
The memory value X is the value of the maximum value Cmax stored in the internal memory of the personal computer 62, and the initial value is a value smaller than the value that can normally be taken as the maximum value Cmax. If Cmax> X, the maximum value Cmax at that time is stored in the internal memory as the memory value X (step S56), and the next step S57.
Proceed to. If Cmax ≦ X in step S35, the process immediately proceeds to step S57.

The personal computer 62 measures the minimum value Cmin of the carrier level in step S57. For example, the change waveform of the carrier level formed in the predetermined time TB is sampled at a predetermined timing, the level of each part of the waveform pattern is recognized, and the minimum value Cmin is measured. When the minimum value Cmin is measured, it is determined whether or not the minimum value Cmin is smaller than the memory value Y (step S5).
8). The memory value Y is the value of the minimum value Cmin stored in the internal memory of the personal computer 62, and the initial value is a value larger than the value that can normally be taken as the minimum value Cmin. If Cmin <Y, the minimum value Cmin at that time is stored in the internal memory as the memory value Y (step S59), and the process proceeds to the next step S60. If Cmin ≧ Y in step S58, the process immediately proceeds to step S60.

In step S60, the personal computer 62 determines whether or not all the tracks in the unreadable portion of the embossed area have been reproduced. If the unreadable portion of the embossed area is 7 tracks, it is determined whether or not the reproduction of all 7 tracks is completed. When all the tracks in the unreadable portion of the embossed area have not been reproduced, the reading position of the optical disk 1 by the recording / reproducing head 2 is jumped to the next one track (step S).
61). After the track jump, the process proceeds to step S33, the repeated reproduction of the one track to which the jump is made is started, and the above steps S54 to S59 are repeatedly executed.

When all the tracks in the unreadable portion of the embossed area have been reproduced by the determination in step S60, the maximum value Cmax and the minimum value Cmin of the carrier level of the read signal in the unreadable portion are finally measured. It will be. Therefore, the personal computer 62 calculates the average value C of the carrier levels in the embossed area by the following equation (2) (step S62).

C = (Cmax + Cmin) / 2 (2) The personal computer 62 calculates the average value C of the carrier level, and then moves the reading position of the optical disk 1 by the recording / reproducing head 2 to the position immediately before the unreadable portion of the embossed area. (Step S63). After the reading position is moved, the repetitive reproduction of one track of the unreadable portion is instructed (step S64). Repetitive reproduction is performed for one track while the operations of FIGS. 10 and 11 described above are executed in response to the repeated reproduction command.

The personal computer 62 sets the variable i to 1 (step S65) and measures the noise level (step S6).
6) The measured noise level is stored in the internal memory as N [i] (step S67). The personal computer 62 determines whether or not all the tracks in the unreadable portion of the embossed area have been reproduced (step S68). If the unreadable portion of the embossed area is 7 tracks, it is determined whether or not the reproduction of all 7 tracks is completed. When all the tracks in the unreadable portion of the embossed area have not been reproduced, 1 is added to the variable i (step S6).
9) Then, the read position of the optical disc 1 by the recording / reproducing head 2 is jumped to the next one track (step S70). After the track jump, the repeat reproduction of the new one track is instructed (step S71). Repeated playback of the one track after the jump is started,
The measured noise level N [i] is stored in the internal memory by performing the above steps S66 and S67 again.

When all the tracks in the unreadable portion of the embossed area have been reproduced by the determination in step S68, the measured noise levels N [1], N for all tracks in the unreadable portion (n tracks). [2], ...
..., N [n] has been measured. Therefore, PC 6
2 is the average value N of the noise level in the embossed area
Calculation is performed according to (3) (step S72).

N = (N [1] + N [2] + ... + N [n]) / n (3) The personal computer 62 further uses the average value C of the carrier level and the average value N of the noise level. The CN ratio is calculated by the following equation (4) (step S73). CN ratio = C / N ...
(4) In the method of calculating the CN ratio shown in FIG. 17, the average value C of the carrier level is calculated first, and then the average value N of the noise level is calculated, but as shown in FIG. The average value N of the noise level is first calculated in steps S63 to S72, then the average value C of the carrier level is calculated in steps S52 to S62, and the CN ratio is calculated using these average values N and C. Is also good. Alternatively, Cmax, Cmin, and N [i] may be measured for each track and calculated after finishing the last track.

Although the embossed area has been described in the above embodiment, the AR of the embossed area is used in the present invention.
The present invention can be applied not only to the calculation of the value and the CN ratio, but also to the case of calculating the performance data of the optical recording medium such as the CN ratio from the measured values in other narrow areas of the optical recording medium. Further, in the above-mentioned embodiments, the optical disc is explained as the optical recording medium, but the present invention can be applied to other optical recording medium such as an optical card having a plurality of tracks formed therein.

[0060]

As described above, according to the present invention, the data indicating the performance of the optical recording medium can be accurately calculated based on the read signal in a narrow area such as the embossed area of the optical recording medium.

[Brief description of drawings]

FIG. 1 is a diagram showing an arrangement structure of respective areas of a DVD-RW.

FIG. 2 is a diagram showing a structure of a recording surface of a DVD-RW.

FIG. 3 is a diagram showing a waveform of a radial push-pull signal including an LPP component.

FIG. 4 is a diagram showing a waveform of a pre-pit detection signal.

FIG. 5 is a diagram showing a pre-pit waveform.

FIG. 6 is a block diagram showing a pre-pit waveform measuring device to which the present invention is applied.

7 is a block diagram showing a configuration of a head amplifier, a prepit detection circuit, and an LPP interval detection circuit in the device of FIG.

8 is a block diagram showing a schematic configuration of an oscilloscope in the apparatus of FIG.

FIG. 9 is a waveform diagram showing the operation of each part of the LPP interval detection circuit.

10 is a flowchart showing an area determination operation by a personal computer in the apparatus of FIG.

11 is a flowchart showing a trigger signal generating operation by a personal computer in the apparatus of FIG.

FIG. 12 is a waveform diagram showing the operation of each unit during a track jump of the apparatus shown in FIG.

FIG. 13 is a diagram showing an example of a pre-pit waveform displayed on an oscilloscope.

14 is a flowchart showing an AR value calculation operation by a personal computer in the apparatus of FIG.

FIG. 15 is a diagram showing carrier level and noise level display by a spectrum analyzer.

FIG. 16 is a diagram showing a relationship in which wobbling of tracks is in opposite phase and in phase between adjacent tracks.

17 is a flowchart showing a CN ratio calculation operation by a personal computer in the apparatus of FIG.

18 is a flowchart showing another example of the CN ratio calculation operation by the personal computer in the apparatus of FIG.

[Explanation of symbols]

1 optical disc 2 Recording / playback head 5 Pre-pit detection circuit 10 slider 20 4-split photodetector 60 LPP interval detection circuit 61 oscilloscope 62 PC

Continued front page    (72) Inventor Naoji Yanagawa             2626 Hanazono, Tokorozawa, Saitama Prefecture             Near Tokorozawa Factory (72) Inventor Yuko Muramatsu             2626 Hanazono, Tokorozawa, Saitama Prefecture             Near Tokorozawa Factory F-term (reference) 5D029 WA02 WA30 WD30                 5D090 AA01 BB02 BB04 BB11 CC18                       DD05 EE12 GG03 GG09 GG10                       GG26 GG28

Claims (7)

[Claims] 1. At least one of a predetermined narrow area composed of a plurality of tracks in a recording area of an optical recording medium.
A performance data calculation device that measures one predetermined parameter and calculates performance data indicating the performance of the optical recording medium according to the measured value of the predetermined parameter, among the plurality of tracks in the predetermined narrow area. Track specifying means for sequentially specifying at least one track, reading means for repeatedly reading one track specified by the specifying means, and the predetermined parameter is measured based on a read signal from the reading means. Measuring means for obtaining a provisional measurement value by means of the performance data, when the provisional measurement value of the predetermined parameter for each of the plurality of tracks is obtained, the measurement value of the predetermined parameter is determined according to the provisional measurement value. And a determination means for determining for calculating the performance data. 2. The performance data calculation device according to claim 1, wherein the predetermined narrow area is an unreadable portion of an embossed area. 3. The optical recording medium is characterized in that synchronization prepits and information prepits that carry information related to the tracks are repeatedly formed between the tracks, and the reading means is arranged so as to have a first and a first direction in a tangential direction of the tracks. Two light receiving surfaces are divided as two light receiving surfaces, and the reflected light of the light beam applied to the recording surface is received by the first and second light receiving surfaces, and the amount of light received by each of the first and second light receiving surfaces. The first and second light detection signals corresponding to the light detection means are output as the read signal, and the measuring means calculates the difference between the first and second light detection signals output from the light detection means. Subtracting means for calculating and generating a push-pull signal, extracting means for extracting a signal component corresponding to the existing position of the information pre-pit in the push-pull signal, and among the signal components extracted by the extracting means. Detection means for detecting the maximum value of the rack component portion, the maximum value and the minimum value of the component portion of the information pre-pit for each track designated by the designating means as a provisional measurement value of the predetermined parameter, The determining means determines the maximum value WOmax of each of the maximum values of the track component portion detected by the detecting means, the maximum value LPmax of each of the maximum values of the information prepit component portions, and the information prepit component portion. The performance data calculation device according to claim 1, wherein the minimum value LPmin of each of the minimum values is determined as a measurement value of the predetermined parameter. 4. The maximum value WOmax and the maximum value LPmax
And the minimum value LPmin, (LPmin-WOmax) / (L
The performance data calculation device according to claim 3, further comprising a calculation unit that calculates an AR value as the performance data by calculating (Pmax-WOmax). 5. The optical recording medium has the tracks formed in a meandering pattern, and the reading unit sets a maximum value and a minimum value of a carrier level of a wobble signal obtained from the read signal and a noise level to a temporary value of the predetermined parameter. The measuring means has a detecting means for detecting each track designated by the designating means, and the determining means has a maximum value Cmax among the maximum values of the carrier level detected by the detecting means, the carrier. 2. The performance data calculation according to claim 1, wherein the minimum value Cmin of the minimum level values and the average value N of the noise levels detected by the detection means are determined as the measured values of the predetermined parameters. apparatus. 6. The average value C of the carrier levels is (Cmax + Cmi) using the maximum value Cmax and the minimum value Cmin.
n) / 2, and C / N is calculated by using the average value C and the average value N of the noise level.
The performance data calculation device according to claim 5, further comprising a calculation unit that calculates an N ratio as the performance data. 7. At least one of a predetermined narrow area composed of a plurality of tracks in a recording area of an optical recording medium.
A performance data calculation method for measuring one predetermined parameter and calculating performance data indicating the performance of the optical recording medium according to the measured value of the predetermined parameter, wherein a plurality of tracks in the predetermined narrow area are included. A track specifying step of sequentially specifying at least one track, a reading step of repeatedly reading one track specified by the specifying step, and a signal read from the one track specified by the reading step. A measurement step of obtaining the provisional measurement value by measuring the predetermined parameter on the basis of the predetermined parameter; and when the provisional measurement value of the predetermined parameter for each of the plurality of tracks is obtained, the predetermined value according to the provisional measurement value. A determination step of determining a measurement value of the parameter for calculating the performance data; A method for calculating performance data, comprising: