JP2002269773A - Servo balance adjusting method for optical disk recording device, and optical disk recording device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To highly precisely and easily adjust the servo balance of focus servo and tracking servo. SOLUTION: An optical disk 10 on which a track meandering at a prescribed period is formed is irradiated with a laser beam 16 to perform recording. The meandering periodic component included in the light receiving HF signal of return light form the optical disk 10 is detected during the recording. A level balance is adjusted between the light receiving signals for the use of arithmetic operation of servo errors, in the manner that the level of the meandering periodic component shows the minimum or an approximate minimum.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a servo balance adjustment of an optical disk recording apparatus for adjusting a servo balance to an optimum state and improving a recording signal quality in various servos such as a focus servo and a tracking servo for optical disk recording. The present invention relates to a method and an optical disk recording apparatus, in which a servo balance can be adjusted with high accuracy and easily.

[0002]

2. Description of the Related Art Focus servo and tracking servo in optical disk recording calculate a servo error by calculating light receiving signals of return light (disk reflected light) of a recording laser beam, and operate a servo actuator so as to reduce the error. It is realized by driving. Servo balance adjustment is to adjust the level balance between the received light signals when calculating the received light signals.
Since the recording signal quality (jitter and the like) greatly varies depending on the adjustment state of the servo balance, it is required to adjust the servo balance with high accuracy.

In the conventional servo balance adjustment of the focus servo and the tracking servo, the HF signal waveform due to the light receiving signal of the return light at the time of recording changes the narrowing of the falling portion of the waveform by the servo balance as shown in FIG. Using the point that the most constricted state is the state where the servo balance is optimal, in the manufacturing process of the optical disc recording apparatus, the operator observes the HF signal waveform by the light receiving signal of the return light at the time of recording with the oscilloscope. The volume for focus servo balance adjustment and the volume for trunking servo balance (tracking offset) adjustment are individually operated to find the point where the waveform is most narrow, and the respective volumes are fixed to that point.

[0004]

In the conventional servo balance adjustment based on waveform observation, it is difficult to visually judge the most constricted state of the waveform. It was difficult to do. Also, it was difficult to automate the adjustment. The focus servo balance adjustment changes the depth of focus. However, since the type of dye and the thickness of the dye change depending on the type of disk, the optimum servo balance differs depending on the type of disk. Also, the optimum servo balance for the tracking servo balance differs depending on the type of disk. However, according to the above adjustment method, the servo balance has been adjusted and fixed at the factory shipment stage, so that the user could not adjust the servo balance according to the type of disk to be used at the time of use. .

SUMMARY OF THE INVENTION The present invention solves the above-mentioned problems in the prior art, and enables a servo balance to be adjusted with high precision and ease, and also enables adjustment at the time of use. It is intended to provide a device.

[0006]

Generally, in a recordable optical disk, guide grooves forming a recording track meander at a predetermined period (this meander is generally called a wobble). According to an experiment by the inventor, during recording on an optical disc, the meandering cycle component included in the received light signal of the return light from the optical disc fluctuates due to the servo balance, and the servo balance and meandering when the jitter of the recording signal is minimized. It was found that the servo balance when the periodic component became the minimum was almost the same. The present invention seeks to adjust the servo balance using this phenomenon.

That is, according to the servo balance adjusting method of the optical disk recording apparatus of the present invention, recording is performed by irradiating a laser beam onto an optical disk on which a meandering track is formed at a predetermined period, and returning light from the optical disk during the recording. Detecting the meandering cycle component included in the light receiving signal, and adjusting the level balance between the light receiving signals used for the servo error calculation so that the level of the meandering cycle component indicates the minimum value or almost the minimum value. is there. According to this servo balance adjustment method, it is possible to know the optimum state of the servo balance depending on the level, so that it is possible to adjust the servo balance to the optimum state with higher precision and easier than when judging from the waveform. it can.

[0008] Further, the optical disk recording apparatus of the present invention comprises:
An optical head for automatically adjusting a servo balance, irradiating a recording laser beam onto an optical disc to perform recording, and receiving a return light thereof, and an optical head included in a light reception signal of the return light when recording the optical disc. A meandering cycle component detection circuit for detecting a meandering cycle component of a track of an optical disc;
A servo error detection circuit that calculates a predetermined light receiving signal of the optical head to detect a servo error, a servo circuit that drives a servo actuator based on the detected servo error, and corrects the servo error; A level balance adjustment circuit that adjusts a level balance between light reception signals for calculating a servo error, and the level balance adjustment circuit that controls the meandering cycle component to have a minimum value or a substantially minimum value, and And a control circuit for automatically adjusting the level balance between them.

Another optical disk recording apparatus according to the present invention has a servo balance which can be manually adjusted. The optical head performs recording by irradiating a recording laser beam onto the optical disk and receives the return light thereof. A meandering cycle component detecting circuit for detecting a meandering cycle component of a track of the optical disc included in the received light signal of the return light during recording on the optical disc; a display device for displaying a level of the detected meandering cycle component; A servo error detection circuit that calculates a predetermined light receiving signal of the head and detects a servo error;
A servo circuit that corrects the servo error by driving a servo actuator based on the detected servo error; a level balance adjustment circuit that adjusts a level balance between light receiving signals for calculating the servo error; A level balance adjusting operator for manually adjusting a level balance between the light receiving signals by operating a balance adjusting circuit.

According to these optical disk recording devices, the servo balance can be adjusted during use, and the servo balance can be adjusted according to the type of the optical disk. It should be noted that the optical disk recording apparatus of the present invention may be configured by an optical disk drive alone or by a combination of an optical disk drive and a personal computer (for example, a level balance adjustment circuit, a level balance adjustment operator may be arranged on the drive side to control The circuit and the display device can be arranged on the personal computer side, etc.).

As a servo balance detecting device utilizing the same phenomenon as that of the present invention, the optical disk recording device is used by being connected to the optical disk recording device when the optical disk recording device does not have means required for servo balance adjustment. As an example, an input terminal for inputting a light receiving signal of return light of a recording laser beam output from an optical disk recording device, and a meandering cycle component of a track of an optical disk included in the light receiving signal input from the input terminal are detected. One that includes a meandering cycle component detection circuit and a display device that displays the level of the detected meandering cycle component may be considered. According to this, when the light receiving signal of the return light of the recording laser light output from the optical disk recording device is input, the level of the meandering cycle component included in the signal is displayed on the display device, and the optical disk recording is performed while watching the display. The servo balance can be adjusted by adjusting the level balance adjustment circuit in the apparatus to a point at which the minimum level is displayed.

The present invention relates to a CD-R, a CD-R
The present invention can be applied to servo balance adjustment of recording devices for various optical disks such as W, DVD-R, DVD-RAM, and MO.

[0013]

(Embodiment 1) FIG. 1 shows an embodiment of an optical disk drive for both recording and reproduction to which the present invention is applied. This optical disk drive 11 is one in which servo balance adjustment is automated. Optical disk 10
A guide groove (pre-groove) meandering (wobble) at a predetermined period is formed as a recording track on the recording surface of. The wobble cycle is set to 22.05 kHz at the standard speed (1 × speed) in the case of a CD-R. The optical disk 10 is driven to rotate by a spindle motor 12, and recording and reproduction are performed by a laser beam 16 emitted from an optical head 14. The return light of the laser light 16 reflected by the optical disk 10 is received by a four-division light receiving element (PIN photodiode) 18 in the optical head 14. The light receiving signals A, B, C, and D of the respective light receiving elements are converted into current / voltage conversion circuits 20, 22,
At 24 and 26, the signal is converted into a signal having a voltage value corresponding to the signal current value.

The summing amplifiers 28 and 30 calculate A + C and B + D, respectively. The subtraction amplifier 32 has a (B + D) −
(A + C) is calculated and a focus error signal is output. The focus servo circuit 34 controls the focus actuator 3 in the optical head 14 based on the focus error signal.
6 is driven to perform focus control. The focus servo balance adjustment is performed by dividing the output voltage of the addition amplifier 30 and inputting the divided voltage to the non-inverting input terminal of the subtraction amplifier 32.
The adjustment is made by adjusting the volume VR1 of the resistance voltage dividing circuit. The summing amplifiers 38 and 40 calculate A + D and B + C, respectively. The subtraction amplifier 42 calculates (B + C)-(A + D) and outputs a tracking error signal. The tracking servo circuit 44 drives a tracking actuator 46 in the optical head 14 based on the tracking error signal to perform tracking control. The tracking servo balance adjustment is performed by dividing the output voltage of the addition amplifier 40 and inputting the divided voltage to the non-inverting input terminal of the subtraction amplifier 42 by using a resistor voltage dividing circuit including an electrically controlled volume (eg, a voltage controlled volume) VR2 and a resistor R2. The adjustment is performed by adjusting the volume VR2.

The summing amplifier 48 calculates A + B + C + D and outputs an HF signal. The HF signal is sent to a signal reproduction processing system and is also input to a meandering cycle component detection circuit 50. The HF signal input to the meandering cycle component detection circuit 50 has a wobble fundamental frequency (22.05k for CD-R).
Hz × n (n is the recording speed magnification), and 2 when the wobble reference frequency is other than 22.05 kHz other than CD-R.
Enter that number instead of 2.05 kHz. ) Is input to a band-pass filter 52 having a center frequency, and a wobble period component is extracted. The extracted wobble cycle component is amplified by the amplifier 54, rectified by the rectifier circuit 56, smoothed by the low-pass filter 58, and a DC signal (meandering cycle component detection signal) having a level corresponding to the magnitude of the wobble cycle component is obtained. Is output. The control circuit 60 adjusts the electric control type regulators VR1 and VR2 based on this signal,
Automatically adjusts the focus servo balance and tracking servo balance to the optimal state.

FIG. 3 shows a change in jitter when the resistance value of the focus servo balance adjustment volume VR1 is changed variously and recorded and reproduced. The point at which the jitter is minimized is the optimum point of the focus servo balance. The focus servo balance adjustment volume V
FIG. 4 shows a change in the voltage value of the meandering cycle component detection signal when recording is performed while changing the resistance value of R1 in various ways. 3 and 4 that the value of the volume VR1 when the jitter is minimized and the value of the volume VR1 when the meandering period component is minimized substantially coincide with each other. This is because when the focus servo balance is changed as shown in FIG. 5A to change the focal depth of the laser beam 16, the track (guide groove) 62 of the dye layer is irradiated as shown in FIG. 5B. The wobble occurs in a state where the size of the beam spot 16a changes and the beam is most narrowed (in a state where the focus of the laser beam 16 is just on the track 62 as shown in (II) and an optimal focus servo balance state). It is considered that this is because the leakage amount of

FIG. 6 shows a change in jitter when the resistance value of the tracking servo balance adjustment volume (tracking error offset adjustment volume) VR2 is variously changed and recorded and reproduced. The point at which the jitter is minimized is the optimum point of the tracking servo balance. FIG. 7 shows a change in the voltage value of the meandering cycle component detection signal when recording is performed while changing the resistance value of the tracking servo balance adjustment volume VR2 in various ways. 6 and 7 that the value of the volume VR2 when the jitter is minimum and the value of the volume VR2 when the meandering cycle component is minimum substantially match. This is shown in FIG.
When the offset amount of the laser beam 16 is changed by changing the tracking servo balance as shown in (b), the beam spot 1 applied to the track 62 of the dye layer as shown in FIG.
It is considered that the leakage amount of the wobble becomes the smallest when the position of the beam spot 6a is changed and the beam spot 16a is just on the center of the track 62 (optimum tracking servo balance state).

Therefore, the control circuit 60 in FIG. 1 adjusts both the volumes VR1 and VR2 so that the level of the meandering period component detection signal indicates the minimum value during recording. This adjustment operation is performed, for example, in test recording using a PCA (Power Calibration Area) area prepared on the inner peripheral side of the lead-in area of the optical disk, recording by changing the volumes VR1 and VR2 variously, This can be realized by determining and storing the values of the volumes VR1 and VR2 at which the level of the periodic component detection signal is the minimum, and performing the recording while fixing the values of the volumes VR1 and VR2 to the values during the actual recording. Alternatively, at the time of actual recording, the two volumes VR1, V1
By changing the value of R2 as needed in the direction in which the level of the meandering cycle component detection signal decreases, adjustment can be performed in real time. According to this real-time adjustment,
It is possible to cope with a difference in the optimum state of servo balance due to a difference in dye film thickness between the inner and outer circumferences of the disk.

In FIG. 1, the arrangement of the resistor VR1 and the resistor R1 may be interchanged. Similarly, the volume VR2
And the arrangement of the resistor R2 may be exchanged.

(Embodiment 2) FIG. 9 shows an embodiment of an optical disk drive in which servo balance adjustment can be performed manually. FIG. 9A shows a front panel 66 of the optical disk drive 64. On the front panel 66, an entrance 70 of the disc tray 68, a knob 72 for adjusting a focus servo balance, a knob 74 for adjusting a tracking servo balance, a level meter 76 for a meandering cycle component.
Etc. are arranged.

FIG. 9 shows the configuration inside the optical disk drive 64.
(B). 1 are denoted by the same reference numerals. Volume VR1 of focus error detection circuit 27
Here, a manual volume is used, and the resistance value is adjusted by a rotary knob 72 for focus servo balance adjustment. Volume VR2 of tracking error detection circuit 37
Similarly, the resistance value is adjusted by a rotary knob 74 for tracking servo balance adjustment. FIG. 9B shows an arrangement in which the resistor VR1 and the resistor R1 in FIG. 1 are replaced, and the resistor VR2 and the resistor R2 in FIG.

A meandering cycle component detection signal (a DC signal whose level changes in accordance with the magnitude of the wobble component in the HF signal) output from the meandering cycle component detection circuit 50 is supplied to the driver 7.
The signal level is supplied to the level meter 76 via the display 7 and the signal level is displayed. When performing servo balance adjustment, set the optical disk 10 to a recording state (test recording or the like),
When the user looks at the level meter 76, the knobs 72, 74
Turn the knob to stop the knobs 72 and 74 at the position where the display of the level meter 76 becomes minimum (turn one knob to find the minimum point, and when that is completed, turn the other knob to find the minimum point).

(Reference Example) FIG. 10 shows a reference example of a servo balance detecting device utilizing the same phenomenon as the present invention. Figure 1
At 0, (a) is an external view and (b) is an internal configuration diagram. The same parts as those in FIG. 9 are denoted by the same reference numerals. The servo balance detecting device 78 is provided with the H of the optical disk drive.
An HF signal input terminal 80 for inputting an F signal output and a level meter 76 are provided. The meandering cycle component of the HF signal input from the HF signal input terminal 80 is detected by the meandering cycle component detection circuit 50, and the level is displayed on the level meter 76. To perform the servo balance adjustment, set the optical disk in the optical disk drive, set a recording state (test recording, etc.), and adjust the servo balance adjustment semi-fixed volume in the optical disk drive while watching the level meter 76, The volume is stopped at the position where the display of the level meter 76 becomes minimum.

[Brief description of the drawings]

FIG. 1 is a circuit diagram and a block diagram showing an embodiment of an optical disk recording device of the present invention.

FIG. 2 is a waveform diagram illustrating a conventional servo balance adjustment method.

FIG. 3 is a diagram showing jitter characteristics of a reproduced signal when recording is performed by changing the resistance value of the volume VR1 of FIG. 1 in various ways.

FIG. 4 is a diagram showing voltage characteristics of a meandering period component detection signal when recording is performed while changing the resistance value of the volume VR1 of FIG. 1 in various ways.

FIG. 5 is a diagram for explaining the reason why the characteristics of FIG. 4 are obtained.

FIG. 6 is a diagram showing jitter characteristics of a reproduced signal when recording is performed while changing the resistance value of the volume VR2 of FIG. 1 in various ways.

FIG. 7 is a diagram showing voltage characteristics of a meandering cycle component detection signal when recording is performed while changing the resistance value of the volume VR2 of FIG. 1 in various ways.

FIG. 8 is a diagram for explaining the reason why the characteristics of FIG. 7 are obtained.

FIG. 9 is a front panel layout diagram showing another embodiment of the optical disk recording apparatus of the present invention, and a block diagram showing an internal configuration.

FIG. 10 is an external view showing a reference example of a servo balance detecting device utilizing the same phenomenon as the present invention, and a block diagram showing an internal configuration.

[Explanation of symbols]

Reference Signs List 10 optical disk 11 optical disk drive (optical disk recording device) 14 optical head 16 laser beam 27 focus error detection circuit (servo error detection circuit) 34 focus servo circuit 37 tracking error detection circuit (servo error detection circuit) 44 tracking servo circuit 50 meandering cycle component Detection circuit 60 Control circuit 62 Track 64 Optical disk drive (optical disk recording device) 72 Knob for focus servo balance adjustment (level balance adjustment operator) 74 Knob for tracking servo balance adjustment (level balance adjustment operator) 76 Level meter (display device) 78 Servo balance detector 80 HF signal input terminal (input terminal) VR1 Focus servo balance adjustment volume (level balance adjustment circuit) VR2 Tracking Volume for servo balance adjustment (level balance adjustment circuit)

Claims (7)

[Claims] 1. An optical disc on which tracks meandering at a predetermined cycle are formed by irradiating a laser beam to perform recording, and detecting the meandering cycle component included in a light receiving signal of return light from the optical disc during the recording. A servo balance adjusting method for an optical disc recording apparatus for adjusting a level balance between light receiving signals used for calculating a servo error so that the level of the meandering cycle component indicates a minimum value or a substantially minimum value. 2. An optical head for performing recording by irradiating a recording laser beam onto an optical disk and receiving a return light thereof, a meandering cycle component of a track of the optical disk included in a light reception signal of the return light during recording on the optical disk. Meandering cycle component detecting circuit, which detects a servo error by calculating predetermined light receiving signals of the optical head, and a servo actuator based on the detected servo error. A servo circuit for correcting a servo error; a level balance adjusting circuit for adjusting a level balance between light receiving signals for calculating the servo error; and the level balance so that the meandering cycle component indicates a minimum value or a substantially minimum value. A control circuit for controlling an adjustment circuit to automatically adjust a level balance between the light receiving signals. The optical disc recording apparatus. 3. An optical head for performing recording by irradiating a recording laser beam onto an optical disk and receiving a return light thereof, a meandering cycle component of a track of the optical disk included in a light receiving signal of the return light during recording on the optical disk. Meandering cycle component detecting circuit, a display device for displaying the level of the detected meandering cycle component, a servo error detecting circuit for calculating a predetermined light receiving signal of the optical head and detecting a servo error, A servo circuit that corrects the servo error by driving a servo actuator based on the detected servo error; a level balance adjustment circuit that adjusts a level balance between light receiving signals for calculating the servo error; Operating a balance adjustment circuit to manually adjust a level balance between the received light signals; Optical disc recording apparatus that includes a child. 4. The optical disk recording apparatus according to claim 2, wherein the light receiving signal for detecting the meandering cycle component is an HF signal sent to a signal reproduction processing system. 5. The optical disk recording apparatus according to claim 2, wherein said servo error is a focus error. 6. The optical disk recording apparatus according to claim 2, wherein said servo error is a tracking error. 7. The optical disk recording apparatus according to claim 2, wherein said servo errors are a focus error and a tracking error.