CN1687990A - Method for testing axial rotation defect of optical head moment apparatus - Google Patents
Method for testing axial rotation defect of optical head moment apparatus Download PDFInfo
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- CN1687990A CN1687990A CN 200510066030 CN200510066030A CN1687990A CN 1687990 A CN1687990 A CN 1687990A CN 200510066030 CN200510066030 CN 200510066030 CN 200510066030 A CN200510066030 A CN 200510066030A CN 1687990 A CN1687990 A CN 1687990A
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- torquer
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- axial rotation
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Abstract
The invention relates to a method for detecting axial rotating defect of moment instrument of an optical head, firstly outputting sine signals at different frequencies; driving the moment instrument to dither in the focusing or tracking direction; casting a laser beam upon a reflecting point of an objective of the moment instrument to measure the dithering speed at the reflecting point; integrating the speed signal to obtain displacement response signals of the reflecting point by the excitation of the sine signals, drawing amplitude-frequency characteristic curves for focusing and tracking coils of the moment instrument and obtaining first order resonance frequencies of the focusing and tracking coils; according to the amplitude-frequency characteristic curves, judging the axial rotating defect of the moment instrument. The method is used to improve production technology and ensure the quality of product.
Description
Technical field
The present invention relates to a kind of detection method of axial rotation defect of optical head moment apparatus, relate in particular to the defect inspection method of optical head moment apparatus in the CD drive, belong to the light storage device technical field of performance test.
Background technology
In optical disk system, torquer is the actual execution unit of optical head servo action.Its role is to, read the error signal of obtaining in the process according to optical head at CD, promptly focus on and tracking error signal, drive the object lens motion in real time, the hot spot that the fluctuating vibration that makes focal beam spot can overcome CD brings is in the skew of disc focus direction and tracking direction, thereby accurately drop on the information track of CD, realize high-quality reading and writing data.
The dynamic property of torquer will directly determine the control accuracy that focus servo and tracking servo system can reach, and being influences the key factor that optical head reads accuracy and stability.The performance test of torquer and quality control are extremely important to the production and the quality guarantee of optical head.
In the design and production of torquer, a cardinal principle is to guarantee that three very important points---center of gravity, holding power equivalent action point, driving force equivalent action point---overlap mutually.Owing to some design and processes reasons, for example the movable member mass distribution is asymmetric, the permanent magnet installation site is offset, suspension wire is installed unrelieved stress of improper generation etc. in the suspension wire formula torquer, can cause them to overlap well, at this moment the movable member of torquer can produce the axial rotation around three degree of freedom in motion process.This movable member axially defective of rotation not only can influence the dynamic property of torquer, and will make object lens can't keep parallel with optical disk in motion process, causes light path to deflect, and directly influences the quality of CD drive read output signal.
If can the defective that movable member axially rotates be detected, just can in time find the existence of this defective, and improve production technology targetedly to eliminate this defective, guarantee the product quality in the large-scale production.At present in production practices, also there is not to detect effectively the method for this defective.
Summary of the invention
The objective of the invention is to propose a kind of detection method of axial rotation defect of optical head moment apparatus, detect axial rotation defect according to the dynamic property curvilinear characteristic of optical head moment apparatus.
The detection method of the axial rotation defect of the optical head moment apparatus that the present invention proposes comprises following each step:
(1) exports the sinusoidal signal of fixed amplitude A under the different frequency f from low to high respectively;
(2) torquer produces shake in focus direction or tracking direction under the driving of above-mentioned sinusoidal signal;
(3) beam of laser is shone on the reflection spot of torquer object lens, record the buffeting speed of the focus direction or the tracking direction at this reflection spot place on the object lens;
(4) above-mentioned rate signal is carried out integration, obtain that the displacement response signal in focus direction or tracking direction is Y (f)=B (f) ∠ φ (f) under the sinusoidal signal excitation that this is f in said frequencies, wherein B (f) be torquer in corresponding frequencies is the amplitude of the displacement response signal of focus direction or tracking direction under the sinusoidal signal of f drives, and φ (f) is a torquer in corresponding frequencies is the phase differential between focus direction or tracking direction displacement response signal and this sinusoidal signal under the sinusoidal signal of f drives;
(5) the amplitude frequency characteristic of drafting torquer focusing coil and tracking coil, characteristic horizontal ordinate is the corresponding frequencies f of sinusoidal signal, ordinate is and the corresponding amplitude response of this frequency f
(6) on above-mentioned amplitude frequency characteristic, obtain the first order resonance frequency f of torquer focusing coil or tracking coil
0, i.e. the horizontal ordinate frequency corresponding on the amplitude frequency characteristic with first resonance peak of low-frequency range;
(7) judge according to the amplitude frequency characteristic of torquer focusing coil, if at first order resonance frequency f
0To the 1KHz frequency range, second resonance peak appears, and then the directions X of torquer exists movable member along the defective of X to axial rotation;
(8) judge according to the amplitude frequency characteristic of torquer tracking coil, if at first order resonance frequency f
0The 3rd resonance peak occurs to the 1KHz frequency range, then the Y direction of torquer exists movable member along the defective of Y to axial rotation, if first resonance peak occurs, then the Z direction of torquer exists movable member along the defective of Z to axial rotation.
The detection method of the axial rotation defect of the optical head moment apparatus that the present invention proposes can detect the axial rotation defect of torquer according to the feature of torquer amplitude frequency characteristic, is used in time improving production technology, guarantees product quality.The inventive method is applicable to suspension wire formula torquer.
Description of drawings
Fig. 1 is a torquer movable member orientation synoptic diagram, and the tracking direction of torquer is a directions X, and the focus direction of torquer is the Y direction, and the direction that is parallel to the torquer suspension wire is the Z direction.
Fig. 2 be movable member axially be rotated in reflection synoptic diagram on the amplitude frequency characteristic, three unusual small magnitude resonance peaks on the amplitude frequency characteristic by frequency from small to large order be called first resonance peak, second resonance peak, the 3rd resonance peak successively.
Specific implementation method
The detection method of the axial rotation defect of the optical head moment apparatus that the present invention proposes is at first exported the sinusoidal signal of fixed amplitude A respectively under the different frequency f from low to high; Torquer produces shake in focus direction or tracking direction under the driving of above-mentioned sinusoidal signal; Beam of laser is shone on the reflection spot of torquer object lens, record the buffeting speed of the focus direction or the tracking direction at this reflection spot place on the object lens; Above-mentioned rate signal is carried out integration, obtain that the displacement response signal in focus direction or tracking direction is Y (f)=B (f) ∠ φ (f) under the sinusoidal signal excitation that this is f in said frequencies, wherein B (f) be torquer in corresponding frequencies is the amplitude of the displacement response signal of focus direction or tracking direction under the sinusoidal signal of f drives, and φ (f) is a torquer in corresponding frequencies is the phase differential between focus direction or tracking direction displacement response signal and this sinusoidal signal under the sinusoidal signal of f drives; Draw the amplitude frequency characteristic of torquer focusing coil and tracking coil, characteristic horizontal ordinate is the corresponding frequencies f of sinusoidal signal, and ordinate is and the corresponding amplitude response of this frequency f
On above-mentioned amplitude frequency characteristic, obtain the first order resonance frequency f of torquer focusing coil or tracking coil
0, promptly with the amplitude frequency characteristic on the corresponding horizontal ordinate frequency of first resonance peak of low-frequency range; Amplitude frequency characteristic according to the torquer focusing coil is judged, if at first order resonance frequency f
0To the 1KHz frequency range, second resonance peak appears, and then the directions X of torquer exists movable member along the defective of X to axial rotation; Amplitude frequency characteristic according to torquer tracking coil is judged, if at first order resonance frequency f
0The 3rd resonance peak occurs to the 1KHz frequency range, then the Y direction of torquer exists movable member along the defective of Y to axial rotation, if first resonance peak occurs, then the Z direction of torquer exists movable member along the defective of Z to axial rotation.
Below introduce content of the present invention in detail:
Choose N class frequency value in logarithmic coordinate axle equal intervals from low to high, export the sinusoidal signal of fixed amplitude A respectively successively under these different frequencies f, the choosing of amplitude should guarantee that torquer can normally shake.This sinusoidal signal is applied on the torquer, and the driving moment device produces shake on focus direction or tracking direction.Beam of laser is shone on the reflection spot of torquer object lens, require this point that enough strong reflective light intensity is arranged, the principle of utilizing laser-Doppler to interfere dynamically records the buffeting speed that this reflection spot on the object lens is in focus direction or tracking direction.This rate signal is carried out integration, obtain that the displacement response signal in focus direction or tracking direction is Y (f)=B (f) ∠ φ (f) under the signal excitation that this is f at above-mentioned different frequency, wherein B (f) be torquer in frequency is the amplitude of the displacement response signal of focus direction or tracking direction under the sinusoidal signal of f drives, and φ (f) is a torquer in frequency is the phase differential between focus direction or tracking direction displacement response signal and the drive signal under the sinusoidal signal of f drives.Draw the amplitude frequency characteristic of torquer focusing coil and tracking coil, characteristic horizontal ordinate is the frequency f of sinusoidal drive signals, and unit is hertz (Hz), and horizontal ordinate uses logarithmic coordinate, and ordinate is and the corresponding amplitude response of frequency f
Unit is a decibel (dB); On above-mentioned amplitude frequency characteristic, obtain the first order resonance frequency f of torquer focusing coil or tracking coil
0, i.e. the horizontal ordinate frequency corresponding on the amplitude frequency characteristic with first resonance peak of low-frequency range;
Amplitude frequency characteristic according to the torquer focusing coil is judged, if at first order resonance frequency f
0To the 1KHz frequency range, second resonance peak appears, and then the directions X of torquer exists movable member along the defective of X to axial rotation.
Amplitude frequency characteristic according to torquer tracking coil is judged, if at first order resonance frequency f
0The 3rd resonance peak occurs to the 1KHz frequency range, then the Y direction of torquer exists movable member along the defective of Y to axial rotation, if first resonance peak occurs, then the Z direction of torquer exists movable member along the defective of Z to axial rotation.
In the inventive method, judge that according to torquer amplitude frequency characteristic the foundation of torquer axial rotation defect is explained as follows: be that second order spring oscillator model is fundamental analysis at first with the most frequently used torquer theoretical model.The application point of driving force and gravity is inconsistent, causes the rotation of torquer movable member around the suspension wire direction.Stressing conditions can equivalence be to apply torsional moment on movable part.The rotation of movable member has simultaneously produced the drift angle with the torquer drive current variations, makes the direction of driving force no longer consistent with direction of motion, thereby has formed the driving force component with the drift angle dynamic change.Consider above factor, to the enterprising action mechanical analysis of torquer direction of motion, the model conversation that can get this moment is the quadravalence model.Analyze with finite element method then, finite element method is the important engineering analogy method, uses the finite element model that finite element method is set up torquer, and the situation that has axial rotation is carried out numerical solution, carries out the harmonious response analysis of model analysis.Analysis result shows that the axial rotation of torquer movable member has caused that unusual small magnitude resonance peak has appearred in the medium and low frequency section of the dynamic property curve of torquer after the first order resonant peak.This result is result verification by experiment.
As shown in Figure 1, the direction of three rotary freedoms of sign torquer Figure 2 shows that the distribution of the small magnitude resonance peak that being rotated on the three degree of freedom causes on the amplitude frequency characteristic.The rotation of X, Y, Z direction corresponding respectively second, third, the first small magnitude resonance peak.Wherein the 3rd, first resonance peak occurs on the amplitude frequency characteristic of torquer tracking coil, second resonance peak occurs on the amplitude frequency characteristic of torquer focusing coil, three kinds of resonance peaks all occur in 1kHz with interior frequency band range, and the frequency magnitude relationship is the 3rd resonance peak〉second resonance peak〉first resonance peak.
Utilize the axial rotation of above-mentioned torquer and the corresponding relation of amplitude frequency characteristic, on the torquer amplitude frequency characteristic that obtains according to reality test the unusual resonance peak of small magnitude have or not and occur the position, detect the axial rotation defect of torquer movable member.
Claims (1)
1, a kind of detection method of axial rotation defect of optical head moment apparatus is characterized in that this method comprises following each step:
(1) exports the sinusoidal signal of fixed amplitude A under the different frequency f from low to high respectively;
(2) torquer produces shake in focus direction or tracking direction under the driving of above-mentioned sinusoidal signal;
(3) beam of laser is shone on the reflection spot of torquer object lens, record the buffeting speed of the focus direction or the tracking direction at this reflection spot place on the object lens;
(4) above-mentioned rate signal is carried out integration, obtain that the displacement response signal in focus direction or tracking direction is Y (f)=B (f) ∠ φ (f) under the sinusoidal signal excitation that this is f in said frequencies, wherein B (f) be torquer in corresponding frequencies is the amplitude of the displacement response signal of focus direction or tracking direction under the sinusoidal signal of f drives, and φ (f) is a torquer in corresponding frequencies is the phase differential between focus direction or tracking direction displacement response signal and this sinusoidal signal under the sinusoidal signal of f drives;
(5) the amplitude frequency characteristic of drafting torquer focusing coil and tracking coil, characteristic horizontal ordinate is the corresponding frequencies f of sinusoidal signal, ordinate is and the corresponding amplitude response of this frequency f
(6) on above-mentioned amplitude frequency characteristic, obtain the first order resonance frequency f of torquer focusing coil or tracking coil
0, i.e. the horizontal ordinate frequency corresponding on the amplitude frequency characteristic with first resonance peak of low-frequency range;
(7) judge according to the amplitude frequency characteristic of torquer focusing coil, if at first order resonance frequency f
0To the 1KHz frequency range, second resonance peak appears, and then the directions X of torquer exists movable member along the defective of X to axial rotation;
(8) judge according to the amplitude frequency characteristic of torquer tracking coil, if at first order resonance frequency f
0The 3rd resonance peak occurs to the 1KHz frequency range, then the Y direction of torquer exists movable member along the defective of Y to axial rotation, if first resonance peak occurs, then the Z direction of torquer exists movable member along the defective of Z to axial rotation.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNB2005100660303A CN100369139C (en) | 2005-04-22 | 2005-04-22 | Method for testing axial rotation defect of optical head moment apparatus |
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| CNB2005100660303A CN100369139C (en) | 2005-04-22 | 2005-04-22 | Method for testing axial rotation defect of optical head moment apparatus |
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| Publication Number | Publication Date |
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| CN1687990A true CN1687990A (en) | 2005-10-26 |
| CN100369139C CN100369139C (en) | 2008-02-13 |
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| CNB2005100660303A Expired - Fee Related CN100369139C (en) | 2005-04-22 | 2005-04-22 | Method for testing axial rotation defect of optical head moment apparatus |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN100487384C (en) * | 2007-02-02 | 2009-05-13 | 清华大学深圳研究生院 | Optical head tri-dimensional torquer inclined movement characteristic curve test method |
| CN101158618B (en) * | 2007-11-01 | 2010-10-06 | 清华大学深圳研究生院 | Optical pickup device force moment machine tester and optical pickup device force moment machine characteristic testing method |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH10289476A (en) * | 1997-04-11 | 1998-10-27 | Sony Corp | Inspection method and inspection device for biaxial objective lens actuator |
| SG75940A1 (en) * | 1999-03-24 | 2000-10-24 | Sony Prec Engineering Ct Singa | Objective lens inspection apparatus |
-
2005
- 2005-04-22 CN CNB2005100660303A patent/CN100369139C/en not_active Expired - Fee Related
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN100487384C (en) * | 2007-02-02 | 2009-05-13 | 清华大学深圳研究生院 | Optical head tri-dimensional torquer inclined movement characteristic curve test method |
| CN101158618B (en) * | 2007-11-01 | 2010-10-06 | 清华大学深圳研究生院 | Optical pickup device force moment machine tester and optical pickup device force moment machine characteristic testing method |
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| Publication number | Publication date |
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| CN100369139C (en) | 2008-02-13 |
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