JP2583447B2 - Angle adjustment method of beam train in optical disk recording / reproducing device - Google Patents

Description

Description: FIELD OF THE INVENTION The present invention relates to a beam train in an optical disc recording / reproducing apparatus for irradiating a disc-shaped recording medium with a light beam spot train to record and / or reproduce signals in parallel. The angle adjustment method.

2. Description of the Related Art As a method of recording and reproducing information by irradiating a disk-shaped recording medium with laser light, a magneto-optical recording method using a magneto-optical disk and an optical recording method using an optical disk are known. Have been.

What is the magneto-optical recording method? When information is recorded, a laser beam is first applied to the magneto-optical disk in a spot shape, and only the portion irradiated with the laser beam is heated to a temperature above the Curie point at which the recording medium loses magnetization. I do. If the irradiation of the laser beam is stopped while an external magnetic field is applied at this time, the portion irradiated with the laser beam drops to a temperature below the Curie point and is magnetized in the direction of the external magnetic field. Even if the external magnetic field is removed in this state, the portion irradiated with the laser beam remains magnetized in the same direction as the external magnetic field applied previously, so that information can be recorded.

As described above, in order to reproduce information from the recorded magneto-optical disk, a weak laser beam which does not heat the recording medium to a temperature equal to or higher than the Curie point is irradiated in a spot shape. Then, the Kerr effect in which the rotation direction of the polarization plane of the reflected light of the laser light changes and the Faraday effect in which the rotation direction of the polarization plane of the transmitted light of the laser light changes according to the direction of magnetization of the portion irradiated with the laser light. Therefore, information can be reproduced by detecting the direction of magnetization of the portion irradiated with the laser light from the rotation direction of the polarization plane of the laser light.

In the optical recording method using an optical disk, a strong laser beam is applied to the optical disk in a spot shape, and only the portion irradiated with the laser beam is deformed or deteriorated, and information is recorded by changing the transmittance or the reflectance. When reproducing information, the optical disk is irradiated with a weak laser beam that does not deform or degrade the optical disk in a spot shape, and the intensity of the transmitted light or reflected light from the portion irradiated with the laser beam is detected. To play.

As a method of increasing the speed of recording / reproducing of these magneto-optical disks and optical disks, a multi-beam method of simultaneously recording / reproducing a plurality of tracks on a disk simultaneously using a plurality of light beam spots has been known. . 14th
FIG. 1 is a perspective view showing the relationship between a disc and a light beam spot in this multi-beam system. A disc D has a spiral groove P used for tracking and information recording, and a groove P.
A land L used only for recording information between them is provided.

The plurality of light beam spots Sa to Sd from the multi-beam laser light source are, for example, several tens μm in the rotation direction of the disk D.
Irradiate the disk D at intervals of 1 to 2 μm in the radial direction along a line that makes a small angle to the groove P, and irradiate one of the light beam spots Sa to Sd, for example, light in FIG. The beam spot Sb is arranged so as to irradiate the groove P. At the time of recording, a plurality of tracks T
Are formed in parallel with the groove P, but are not specifically shown on the disk D.

FIG. 15 is a configuration diagram of a tracking detector in the case where reproduction is performed using reflected light on the disk D. The two-part photodiodes 1 a and 1 b are connected to the differential amplifier 2, respectively. First, the light beam spot on the disk D
Sa to Sd are reflected and partly incident on the two-part photodiodes 1a and 1b via the light receiving optical system. Reflection spot Ra
~ Rd, the spots Ra, Rc, Rd reflected by the land L
Is incident at a light intensity equal to the two-divided photodiodes 1a and 1b regardless of whether the tracking is correct or not by optical adjustment in advance.

On the other hand, the spot Rb reflected by the groove P
Are diffracted at the left and right ends of the groove P, and strong reflected light is generated on the left and right of the groove P. Therefore, when the intensity of the light beam spot Sb incident on the groove P is different at the left and right end portions of the groove P, that is, the light beam spot Sb is irradiated while being shifted from the center of the groove P,
If tracking is not appropriate, the reflected spot Rb
Since the intensity of the left and right is different,
The light amounts incident on a and 1b are also different.

That is, only when tracking is performed, the amount of light incident on the two-part photodiodes 1a and 1b of the reflection spot Rb becomes equal. Since the difference between the incident light amounts of the two-divided photodiodes 1a and 1b is detected by the differential amplifier 2, if a control device (not shown) adjusts the differential output to be zero, the light beam spot Sb is formed in the groove P It will be possible to accurately track up.

[Problems to be Solved by the Invention] However, in such a tracking method, of the plurality of light beams, only the tracking of the light beam tracing the groove P is performed, and the other light beams are not controlled. No tracking control is performed.

Therefore, when the angle between the multi-beam spot array and the groove P changes due to a temperature change or the like, or when the disc D
If the recording track T of the disc D to be reproduced is slightly deviated from the normal state when the data is exchanged and reproduced, a deviation occurs in the tracking of a plurality of light beams for which the tracking control is not performed, There is a disadvantage that information recording / reproduction cannot be performed well.

[Object of the Invention] An object of the present invention is to improve the tracking accuracy of a plurality of light beams emitted from an optical head onto a disk and to perform high-quality recording and / or reproduction of information. An object of the present invention is to provide a method of adjusting the angle of a beam train in a recording and reproducing apparatus.

[Summary of the Invention] A method for adjusting the angle of a beam train in an optical disc recording / reproducing apparatus according to a first invention for achieving the above-mentioned object comprises: a multi-beam light source having a plurality of light sources arranged in a line;
A projection optical system for projecting a plurality of light beams emitted from the multi-beam light source as a light beam spot array on a disk-shaped recording medium, and tracking detection for receiving reflected light of the light beam spot array on the recording medium A recording / reproducing apparatus, wherein one of the plurality of beams irradiates a groove for tracking and the other beam irradiates a land for recording / reproduction, wherein the multi-beam light source forms on the recording medium. When adjusting the angle formed between the light beam spot array and the tracking groove previously formed on the recording medium, a reproduction signal of a reflected light of the light beam that is farthest from the light beam tracing the groove The angle is adjusted by maximizing the amplitude value of.

Further, a method for adjusting the angle of a beam train in an optical disk recording / reproducing apparatus according to a second invention is a method of adjusting a beam angle of a multi-beam light source in which a plurality of light sources are arranged in a line. A projection optical system for projecting a beam spot array on a disk-shaped recording medium; and a tracking detection system for receiving reflected light of the light beam spot array on the recording medium.
One is a recording / reproducing apparatus which irradiates a groove for tracking and irradiates a land for recording / reproducing with the light beam spot array formed on the recording medium by the multi-beam light source and previously on the recording medium. When adjusting the angle formed by the formed tracking groove, the angle is adjusted by making the reproduction signal of each reflected light of the light beam spot row continuous in a sine wave shape. I do.

[Embodiment of the Invention] The present invention will be described in detail based on the embodiment shown in Figs.

FIG. 1 shows a configuration diagram of a function of rotating a light beam spot array. A multi-beam laser diode 10 is housed in a package 11 and attached to a holder 12.
A collimator lens 1 is placed on the optical axis of the laser diode 10.
3. The mirror 14 is sequentially arranged, and the objective lens 15 and the disk D are sequentially provided in the reflection direction above the mirror 14. The holder 12 has a projection 12a at the left end, and a wedge-shaped adjustment tool 16 is slidably contacting the projection 12a. The wedge-shaped adjustment tool 16 is movable in the left-right direction by an adjustment knob 17. On the other hand, a projection 12b is provided at the right end of the holder 12, and a compression spring 18 is interposed between the projection 12b and a frame (not shown).

The multi-beam emitted from the laser diode 10 is converted into parallel light by a collimator lens 13 and reflected by a mirror 14 to form a beam spot train B on a disk D by an objective lens 15. At this time, when the adjustment knob 17 is turned in an appropriate direction, the wedge-shaped adjustment tool 16 moves left and right.
The holder 12 rotates integrally with the laser diode 10 and the package 11 in the direction of the arrow around the optical axis by the cooperative action with the spring 18.

Thus, when the laser diode 10 is rotated,
Since the light beam spot array B formed on the disk D also rotates in the direction of the arrow, the inclination angle of the light beam spot array B with respect to the groove P, that is, the pitch of the multi-track T formed by the light beam spot array B is minute. It can be adjusted. Therefore, by turning the adjustment knob 17 manually or automatically, a favorable tracking state can be always obtained.

In addition, instead of the protrusion 12a, the wedge-shaped adjustment tool 16, and the adjustment knob 17 as a rotation mechanism, a piezoelectric element can be interposed between the holder 12 and a frame (not shown). Those that can change about 100 μm in the thickness direction can be used. That is, the laser diode 10 can be rotated together with the holder 12 by supplying a voltage to the piezoelectric element and changing the thickness appropriately.

FIG. 2 is a plan view showing a light beam spot array B formed on the disk D when the holder 12 rotates. When the beam spot B2 traces the groove P by tracking control, the track pitch is changed. For example, about 1.6μ
m, the distance between beam spots B2 and B4 is 45 μm,
Considering a circular arc having a radius of 45 μm around B2, if the beam spot B4 moves by 0.5 μm, the deflection angle Δθ corresponds to an angle of ± 40 minutes. Therefore, when rotating the holder 12 about the optical axis, if the radius of rotation r of the beam train of the laser diode 10 is 5 mm, the thickness change of the piezoelectric element needs to be ± 50 μm.

FIG. 3 shows a first embodiment using a piezoelectric element. A piezoelectric element 20 is provided at the left end of the holder 12, and a beam splitter 21 is provided below the disk D instead of the mirror 14 shown in FIG.
Are provided, and a lens 22 and a photodetector 23 are sequentially arranged in a new downwardly divided optical axis direction. Also, the output of the photodetector 23 is a maximum amplitude value adjusting unit 24 for the reproduced signal.
The output of the maximum amplitude adjusting unit 24 is connected to a piezoelectric element driver 25. Note that the same reference numerals as those in FIG. 1 denote the same members, and a description thereof will be omitted.

With this configuration, the multi-beam emitted from the laser diode 10 is reflected upward by the beam splitter 21 through the collimator lens 13, reaches the disk D via the objective lens 15, and the light reflected by the disk D again It passes through the objective lens 15 and part of it passes through the beam splitter 21
Is transmitted through the lens 22, enters the photodetector 23, and is photoelectrically converted into a reproduced signal A.

In order to make the tracking of the multi-beam and the disk D in the best state, the groove P of the disk D is controlled by the tracking control.
May be adjusted so that the amplitude of the reproduced signal A by the light beam that is farthest from the light beam tracing is maximized. For example, since the beam spot B2 traces the groove P in FIG. 2, the reproduced signal from the beam spot B4 is used and the amplitude is adjusted so that the amplitude becomes maximum.

Hereinafter, for simplicity, a tracking method will be described for a case where there are four multi-beams, that is, four beam spots B1 to B4 as shown in FIG. First, when performing tracking manually, it is not necessary to install the maximum amplitude value adjusting unit 24, and the output is maximized while observing the reproduced signal obtained from the photodetector 23 with a monitor or the like (not shown). The control voltage En of the piezoelectric element driver 25 is manually adjusted, and the adjustment is completed when the reproduction signal becomes maximum.

On the other hand, an automatic tracking mechanism, that is, an amplitude maximum value adjusting unit 24
Is used, the reproduction signal of the beam spot B4 obtained from the photodetector 23 is input to the maximum amplitude value adjustment unit 24. The maximum amplitude adjusting unit 24 controls the output voltage of the piezoelectric element driver 25 according to the magnitude of the amplitude of the input reproduction signal, and controls the piezoelectric element 20 so that the amplitude of the reproduction signal always becomes the maximum.
To control the rotation angle.

Hereinafter, a specific control operation of the maximum amplitude value adjusting unit 24 will be described with reference to the graph of FIG. 4 and the flowchart of FIG. FIG. 4 is a graph showing the relationship between the control voltage En of the piezoelectric element 20 and the reproduced signal An obtained from the photodetector 23 at that time. First, in step 100 of the flowchart of FIG. 5, when the initial control voltage E1 is output from the piezoelectric element driver 25 to the piezoelectric element 20, the reproduction signal A1 sent from the photodetector 23 is obtained in the subsequent step 101.

Next, at step 102, the control voltage E1 is set to a predetermined voltage Δ
E to increase the control voltage E2, and the piezoelectric element driver 25
To the piezoelectric element 20. In the following step 103, the reproduction signal A2 at the time of the control voltage E2 is obtained from the photodetector 23, and in the next step 104, the magnitudes of the reproduction signals A1 and A2 are compared.
If it is larger than 1, the process returns to step 102 again and the control voltage E2
Is increased by ΔE.

Such an increase in the control voltage En is repeatedly performed, and when the magnitude of the reproduction signal An becomes equal to or less than An-1 in step 104, the process proceeds to step 105, and the control voltage En is increased by an amount Δ
The value is reduced by a small value Δe which is about a fraction of E and output from the piezoelectric element driver 25 to the piezoelectric element 20. In the following step 106, the reproduction signal An at that time is obtained from the photodetector 23. In step 107, if the reproduction signal An-1 before the control voltage En is decreased by Δe is equal to the reproduction signal An after the decrease, The process jumps to step 109 to end the tracking adjustment.

On the other hand, if the sizes are not equal in step 107,
Proceeding to step 108, the magnitudes of the reproduced signals An-1 and An are compared. If An is greater, the process returns to step 105 again, and the control voltage En is similarly reduced by Δe. If the reproduction signal An is smaller than An-1, the process proceeds to step 109, where the control voltage En at that time is set as the final control voltage EL, and the tracking ends.

In the graph of FIG. 4, the adjustment is performed in the order of... In accordance with the flowchart of FIG. 5, the final control voltage EL is E9, and the reproduced signal A9 at that time has almost the maximum value. . Therefore, since the reproduced signal by the beam spot B4 furthest from the beam spot B2 tracing the groove P of the disk D is maximum, the angle between the light beam spot array B and the track T shown in FIG. It can be said that.

In the above embodiment, the method of automatic adjustment when the piezoelectric element 20 is used has been described. However, as shown in FIG.
A similar method can be adopted also when the control knob is configured so that the adjustment knob 17 is automatically rotated.

FIG. 6 is an explanatory view of a second embodiment using still another multi-beam interval adjusting mechanism. The collimator lens 13 and the beam splitter in the first embodiment shown in FIG.
A half mirror 30 is inserted between the light source 21 and the imaging mirror 31 and a two-division photodiode 32 which is divided so as to divide the beam spot Bm into two equal parts and receive light in the reflection direction downward. Are located. Two-segment photodiode
The output of 32 is sequentially connected to a differential amplifier 33, a band-pass filter 34, an amplitude minimum value adjuster 35, and a piezoelectric element driver 25. It is not necessary to provide the maximum amplitude value adjusting section 24 of the second embodiment, and the photodetector 23 is used for focusing or for detecting a reproduced signal of information in this case.

The multi-beam emitted from the laser diode 10 passes through the collimator lens 13 and the half mirror 30, is reflected upward by the beam splitter 21, and forms a beam spot B on the disk D via the objective lens 15. The reflected light passes through the objective lens 15 again, a part of which passes through the beam splitter 21 and reaches the photodetector 23 through the lens 22, a part of which is reflected by the beam splitter 21, and further a half mirror.
The light is reflected downward at 30 and is imaged on a two-division photodiode 32 via an imaging lens 31. The divided output of the two-division photodiode 32 is input to the differential amplifier 33.

FIG. 7 shows a differential amplifier 33 in which only focus control is performed by a mechanism not shown and tracking control is not performed.
3 shows an output waveform of the first embodiment. Since the disc D usually has a slight eccentricity, when the tracking control is not performed, the beam spot Bm moves across the tracks T of the rotating disc D by several tracks. If there is a beam spot Bm on the land L, the reflection spot is 2
Since an equal amount of light is incident on each diode of the divided photodiode 32, the output of the differential amplifier 33 becomes zero. But,
When the beam spot Bm is located on the groove P, strong diffraction occurs at the edge of the groove P, and the reflection spot becomes non-uniform on the left and right. Is no longer incident, and the differential amplifier 33
Is no longer zero.

That is, the sinusoidal portion of the output waveform shown in FIG. 7 corresponds to the period from when the beam spot Bm starts being irradiated to the groove P until the beam spot stops being irradiated.
This corresponds to the case where Bm is irradiated on the land L. In addition,
In FIG. 7, for simplicity, as shown in FIG. 2, four multi-beams, that is, four beam spots Bm, B1, B2, B3 and B4
FIG. 7A shows a differential amplifier in which only the beam spot B1 is received by the two-division photodiode 32.
33 is an output waveform diagram of FIG. 33, and similarly in the following (b), (c),
(D) is an output waveform diagram of each of the beam spots B2 to B4.

If these four beam spots B1, B2, B3, B4 are arranged on the disk D at an accurate spot interval of 1/4 of the pitch of the groove P in the radial direction of the disk D,
When the beam spots B1 to B4 at that time are received by the two-division photodiode 32, the waveforms shown in FIGS. 7A to 7D are smoothly continuous, and a sine wave as shown in FIG. Obtained as the output of amplifier 33.

FIG. 8 shows the relationship between the radial spot distance of the zoom spots B1 to B4 on the disk D and the output of the differential amplifier 33. FIG. (B) is an output waveform when the pitch is 1/4 of the pitch of the groove P, and (c) is an output waveform when it is wider than 1/4. FIG. 8 (a) shows a clean continuous sine wave, but in FIG. 8 (b), discontinuity of the waveform is observed in the interval d1 and in FIG. 8 (c), the discontinuity of the waveform is observed in the interval d2. The discontinuity of these waveforms is one in four cycles in the case of four beam spots.
Appear once, and in the case of m beam spots,
Will appear multiple times.

Accordingly, in the case of m multi-beams, only the focusing control is performed without performing the tracking control.
By adjusting so that the frequency component of 1 / m of the fundamental frequency of the output waveform by the differential amplifier 33 is minimized, the multi-beam Bm
Can be optimized, and the tracking state when tracking control is performed can be optimized.

When these adjustment operations are performed manually, the amplitude minimum value adjustment unit 35 shown in FIG. 6 is not necessary, and the output signal of the differential amplifier 33 is input to the bandpass filter 34, and 1 / m of the fundamental frequency is output. Only frequency components are filtered. Therefore, by observing the output of the bandpass filter 34 with a monitor or the like (not shown) and manually adjusting the control voltage En of the piezoelectric element driver 25 so as to minimize the output, the beam spot interval in the radial direction of the disk D can be optimized. Can be

On the other hand, when the same adjustment is performed automatically, the output of the bandpass filter 34 is input to the minimum amplitude value adjusting unit 35, and the minimum amplitude value adjusting unit 35 selects the piezoelectric element according to the magnitude of the 1 / m frequency component. The control voltage En of the driver 25 is adjusted, and the piezoelectric element 20 is controlled so that the output of the bandpass filter 34 is minimized.

Hereinafter, a specific control operation of the minimum amplitude value adjusting unit 35 will be described with reference to the graph of FIG. 9 and the flowchart of FIG. Figure 9 is a graph showing the relationship between the output I _n of the amplitude of the frequency component of 1 / m of the control voltage En and the fundamental frequency of the piezoelectric element 20, i.e. the bandpass filters 34. First, in step 200 of the flowchart of FIG. 10, when the initial control voltage E1 is output from the piezoelectric element driver 25 to the piezoelectric element 20, in a subsequent step 201, the output I1 is output from the bandpass filter 34.
Get.

Next, at step 202, the control voltage E1 is reduced by a predetermined amount ΔE to obtain a control voltage E2, which is output from the piezoelectric element driver 25 to the piezoelectric element 20. In the following step 203, the output I2 at the time of the control voltage E2 is obtained from the bandpass filter 34, and the next step
At 204, the magnitudes of the outputs I1 and I2 are compared, and if the output I2 is smaller than I1, the process returns to step 202 again to set the control voltage E2 to ΔE
Decrease by minutes. Such a decrease in the control voltage En is repeatedly performed. If the output In becomes equal to or more than In-1 in step 204, the process proceeds to step 205, and the control voltage En is decreased by ΔE.
The output is increased from the piezoelectric element driver 25 to the piezoelectric element 20 by increasing the value by a small value Δl which is about a fraction of the value.

In the following step 206, the output In at that time is obtained from the bandpass filter 34. In step 207, if the output In-1 before increasing the control voltage En by Δe is equal to the output In after the increase, the process proceeds to step 209. Jump to end multi-beam spacing adjustment. On the other hand, if not equal, the process proceeds to step 208, where the magnitude of the output In-1 and In is compared. If the value of In is smaller, the process returns to step 205 again, and the frequency component En is similarly increased by Δe. Let it. Output In
If the difference is smaller than In-1, the process proceeds to step 209, where it is set as the final control voltage EL, and the multi-beam interval adjustment ends.

Thus, in the graph of FIG. 9, the adjustment is performed in the order of... According to the flowchart of FIG. 1, and the control voltage is at the minimum value at E7 and the output I7 at that time. Therefore, the m light beam spot arrays B are accurately aligned in the radial direction of the disk D at an interval of 1 / m of the pitch of the groove P. Bm also accurately traces the track T, and a good reproduction and / or recording state can be obtained.

It should be noted that the various tracking control methods described above can be operated continuously during reproduction, and can be used by fixing them to predetermined preset values during recording.
Therefore, it is possible to sufficiently cope with the reproduction of a disc having an unstable track pitch or a disc whose track pitch is out of standard, and to form a track having a stable track pitch and conforming to the standard at the time of recording, thereby performing high quality recording. it can.

Next, mechanical means for adjusting the angle between the light beam spot array B formed on the disk D by the multi-beam laser diode 10 and the groove P of the disk D will be described. In FIGS. 1, 3 and 6, the laser diode 10 is mounted on the holder 12 and the light source itself is rotated about the optical axis to form the light beam spot array B and the groove P. Although the angle is adjusted, even if the mirror 14 in FIG. 1 or the beam splitter 21 in FIGS. 3 and 6 is rotated about the optical axis toward the objective lens 15, the light beam spot array B It is possible to adjust the angle between the groove and the groove P.

In this case, for example, as shown in FIG.
Is a rotary shaft 40 on a turntable 40 rotatable about an optical axis O.
The rotating shaft 40a is inserted around the base 41 and fixed. As a rotation mechanism of the turntable 40, for example, a rotation mechanism of the holder 12 is applied, and as shown in FIG.
A piezoelectric element 42 is provided between the right end of 40 and the protrusion 41a provided on the base 41, and between the protrusion 40b provided at the left end of the turntable 40 and the protrusion 41a. A compression spring 43 is provided.

Alternatively, as shown in FIG. 13, a projection 40c is provided at the right end of the turntable 40 instead of the piezoelectric element 42, and a wedge-shaped adjustment tool 45 movable left and right is slid on the projection 40c by an adjustment knob 44. The principle of the rotation mechanism may be exactly the same as that of the holder 12 described above.

When the mirror 14 or the beam splitter 21 is rotatable in this manner, the laser diode 10 does not need to be attached to the holder 12, but may be simply fixed to a frame (not shown). In addition, other configurations are the first,
The description is omitted because it is the same as that of the second embodiment. In addition,
As the tracking control method, the method described in the first and second embodiments can be used as it is, and the adjustment can be performed automatically or manually.

[Effect of the Invention] As described above, in the method for adjusting the angle of the beam train in the optical disk recording / reproducing apparatus according to the present invention, the multi-beam light source can rotate around the optical axis of the projection optical system, Since the tracking is performed by detecting the change in reflected light in the disk, the distance between the beam spots projected on the disk in the radial direction of the disk is finely adjusted by finely rotating the multi-beam light source, and the track pitch of the disk is adjusted. Can be accurately matched with

Therefore, at the time of recording, the pitch of the track created on the disk does not become inaccurate as in the prior art, and at the time of reproduction, even if the recording state is bad and the track pitch is considerably deviated from the standard, the disk cannot be reproduced conventionally. Even in this case, since the reproduction can be sufficiently performed by finely adjusting the interval between the multi-beams, it is possible to record and / or reproduce information with extremely high quality and high reliability as compared with the related art.

[Brief description of the drawings]

FIGS. 1 to 13 show an embodiment of a beam train angle adjusting method in an optical disk recording / reproducing apparatus according to the present invention.
FIG. 1 is a configuration diagram of a rotation mechanism of a light beam spot array, and FIG.
FIG. 3 is a plan view of an arrangement of beam spots on the disk, FIG. 3 is a block diagram of the first embodiment, FIG. 4 is a graph illustrating a method of detecting the maximum value of a reproduced signal, FIG. FIG. 6 is a block diagram of the second embodiment, FIG. 7 is an output waveform diagram of the differential amplifier, FIG. 8 is an explanatory diagram showing the relationship between the arrangement of the optical beam spot array and the output waveform of the differential amplifier, and FIG. The figure is a graph explaining the method of detecting the minimum value of the output of the bandpass filter, and FIG.
FIG. 10 is a flowchart thereof, FIG. 11 is a partial configuration diagram of another rotation adjuster, FIG. 12 is a plan view of a turntable, FIG. 13 is a plan view of a modification of the turntable, and FIG. FIG. 15 is a configuration diagram of a conventional tracking detector. Reference numeral 10 is a laser diode, 11 is a package, 12 is a holder, 13 is a collimator lens, 14 is a mirror, 15 is an objective lens, 16 and 45 are wedge-shaped adjustment tools, 17 is an adjustment knob, and 18 and 43.
Is a spring, 20 is a piezoelectric element, 21 is a beam splitter, 22, 31
Is a lens, 23 is a photodetector, 24 is an amplitude maximum value adjuster, 25 is a piezoelectric element driver, 30 is a half mirror, 32 is a two-part photodiode, 33 is a differential amplifier, 34 is a bandpass filter, and 35 is amplitude A minimum value adjusting unit, 40 is a turntable, and D is a disk.

Claims (2)

(57) [Claims] 1. A multi-beam light source comprising a plurality of light sources arranged in a line, and a projection optical system for projecting a plurality of light beams emitted from the multi-beam light source as a light beam spot array on a disk-shaped recording medium. And a tracking detection system for receiving reflected light of the light beam spot array on the recording medium, wherein one of the plurality of beams irradiates a tracking groove and the other beam is a recording / reproducing land. In the recording and reproducing apparatus for irradiating, when adjusting the angle between the light beam spot array formed on the recording medium by the multi-beam light source and the tracking groove formed in advance on the recording medium, The angle is adjusted by making the amplitude value of the reproduction signal of the reflected light of the light beam farthest from the light beam tracing the groove maximum. Angle adjusting method of a beam column in the optical disc recording and reproducing apparatus according to claim. 2. A multi-beam light source comprising a plurality of light sources arranged in a line, and a projection optical system for projecting a plurality of light beams emitted from the multi-beam light source as a light beam spot array on a disk-shaped recording medium. And a tracking detection system for receiving reflected light of the light beam spot array on the recording medium, wherein one of the plurality of beams irradiates a tracking groove and the other beam is a recording / reproducing land. In the recording and reproducing apparatus for irradiating, when adjusting the angle between the light beam spot array formed on the recording medium by the multi-beam light source and the tracking groove formed in advance on the recording medium, The angle adjustment is performed by making a reproduction signal of each reflected light of the light beam spot train continuous in a sine wave shape. Angle adjusting method of a beam column in living devices.