CN101369432B - Regulation means for inclination angle of optical head - Google Patents

Abstract

The invention discloses a method for adjusting inclination angle of an optical head, which comprises moving the optical head to a first position of an optical recording media and focusing; acquiring a first focusing control force and a first optimal inclination angle of the first position; moving the optical head to a second position of an optical recording media and focusing; acquiring a second focusing control force and a second optimal inclination angle of the second position; working out optical sensitivity parameter according to the first optimal inclination angle, the second optimal inclination angle, the first focusing control force and the second focusing control force; when moving the optical head to a specific position, recording the focusing control force corresponding to the specific position and working out the optimal inclination angle corresponding to the specific position based on the focusing control force and the optical sensitivity parameter to adjust the inclination angle of the optical head. The invention can solve the problem that in the prior art the quality is not steady when recording information to the optical disk or reading information from the optical disk.

Description

The method of adjustment of inclination angle of optical head

Technical field

The invention relates to the optical storage media technology, and particularly relevant for a kind of method of adjustment of inclination angle of optical head.

Background technology

Usually, be used for optical recording and the device that reads, optical head (pickup head) needs an actuator (actuator) to adjust object lens (object lens), this actuator can accurately move on to optical head position and the correct angle of deflection that needs, make optical head place device to read information with correct angle from discs in correct position, or to the discs recorded information.Yet, when desire to read or the discs of recorded information when warpage (curved) occurring, or the inclination of optical head (tilt) is when angle is incorrect, the information that then reads or write down will produce deterioration (deteriorates), make to read information and to the quality instability of discs recorded information from discs.In order to compensate this deterioration situation, must measure the relative tilt angle between optical head and the discs, and be adjusted the angle of inclination of optical head in good time, make optical head to carry out read-write operation to discs as far as possible with the angle vertical with discs.

Fig. 1 is the Organization Chart of prior art medium dip adjusting gear.As shown in Figure 1, this inclination adjusting device comprises optical head 10, angle detection and object lens 16.Optical head 10 can rotate for the center in rotating shaft 18, and is controlled the rotation of optical head 10 by actuator (this figure does not illustrate).And angle detection comprises optical transmitting set 12 and two optical receiver 14a and 14b, behind the optical transmitting set 12 emission light, utilize optical receiver 14a and 14b to receive the light of reflection, can detect the tilt quantity of optical head 10, and utilize this tilt quantity control actuator, optical head 10 is carried out the adjustment at angle of inclination.This mode need dispose angle detection and come with the foundation as the angle of inclination of adjusting optical head with the relative tilt angle between detection optical head and the discs.

Fig. 2 is the structural drawing that does not need the optical pickup tilt angle Adjustment System of angle detection in the prior art.This pitch angle Adjustment System need not to be provided with angle detection, and cost is lower.As shown in Figure 2, this method only need adopt tilt control module 20 to obtain coherent signal, tilt quantity according to the signal analysis of obtaining.Specifically, tilt control module 20 comprises regenerated signal generation unit 22, jitter detector 23, tilt control unit 24, tilt drive 25 and internal storage location 26.Wherein, regenerated signal generation unit 22 is used for radio frequency (Radio Frequency that optical head is produced, RF) conversion of signals becomes 8-14 modulation (Eight to Fourteen Modulation is hereinafter to be referred as EFM) signal, for example uses cutter (slicer) to cut out 0 and 1 signal.Jitter detector 23 receives the EFM signal that regenerated signal generation unit 22 produces, and detects the amount of jitter of this EFM signal.Described amount of jitter is meant the degree of EFM signal front and back drift.The different inclination controlling value (different inclination controlling values are corresponding to different optical pickup tilt amounts) of tilt control unit 24 outputs, and the corresponding with it amount of jitter of record, and it is minimum or be lower than the inclination controlling value of the amount of jitter correspondence of shake critical value to filter out amount of jitter, with as the inclination controlling value of controlling the optical pickup tilt amount.25 inclination controlling value output drive signals of determining according to tilt control unit 24 of tilt drive change the tilt quantity of optical head to optical module 21.Described inclination controlling value can be digital signal, and is stored in the internal storage location 26.And should the inclination controlling value (Digital/Analog Converter DAC) exports tilt drive 25 to after the conversion through digital analog converter.Tilt drive 25 is with the pairing signal of inclination controlling value, and for example the voltage signal of 0-4V converts to and drives the drive signal that optical head rotates.

Though the optical pickup tilt angle method of adjustment shown in Fig. 2 does not need angle detection can adjust the optical pickup tilt angle to better position, on the discs engraving data must be arranged, just can utilize the amount of jitter of EFM signal to adjust the optical pickup tilt angle.For blank (nude film), then,, adjust the optical pickup tilt angle so can't utilize the EFM signal to obtain the inclination controlling value because can't obtain the EFM signal.

Figure 3 shows that U.S. Patent Publication No. is the synoptic diagram of the disclosed inclination angle of optical head modification method of application documents of US2005/0117473.As shown in Figure 3, the face of the method hypothesis discs is a kind of plane inclined, just the straight line between position P1 and the position P2 (straight line) is considered as the face of discs.Optical head 32 can keep a fixed range with discs 31 through after the focus control.Specifically, after starting the mechanism of focus control, CD-ROM drive meeting basis is according to focus error signal (focus error, FE) output focus control signal (focus control signal, FCS) lens of controlling optical head move up and down, and make the lens of optical head and discs 31 keep a fixed range.So as shown in Figure 3, when optical head 32 during at position P1 and position P2, the relative distance of the lens of optical head and discs 31 is fixed.Therefore, as long as the distance lambda of location aware P1 and position P2, and the position P1 difference in height β (lens displacement β) corresponding with position P2, just can calculate the angle of inclination of discs, this angle of inclination is used to revise the angle of inclination of optical head.The account form of tiltangle is:

$\mathrm{\θ}={\tan }^{-1}\left(\frac{\mathrm{\β}}{\mathrm{\λ}}\right)$

Yet in fact, the face of discs is not a kind of plane inclined, and near a kind of curved surface.And above-mentioned hypothesis must be quite short in the distance between position P1 and the position P2, and could set up under the not serious situation of discs warpage (curved) situation.If discs warpage situation is comparatively serious, then must the measuring light disc on many different positions, aforesaid way just can accurately be revised the angle of inclination of optical head.But along with the position of measuring increases, the spent time also can be more.Therefore in addition, this method is to utilize the mode approximating curve of straight line, and the angle of inclination that obtains is not accurate enough, still can cause reading information and to the quality problem of unstable of discs recorded information from discs.

Summary of the invention

In view of this, the object of the present invention is to provide a kind of inclination angle of optical head method of adjustment and system, with in effective solution prior art to the discs recorded information or read the problem of quality of information shakiness from discs.

For this reason, the present invention proposes a kind of method of adjustment of inclination angle of optical head.This method comprises: move the primary importance of above-mentioned optical head to optical record medium, and start focusing function; Obtain the focus control power at primary importance place, be designated as the first focus control power, and the optimum tilt angle of obtaining the primary importance place, be designated as the first optimum tilt angle;

Move the second place of described optical head, the line focusing of going forward side by side to described optical record medium; Obtain the focus control power at second place place, be designated as the second focus control power, and the optimum tilt angle of obtaining second place place, be designated as the second optimum tilt angle;

According to the described first optimum tilt angle, the second optimum tilt angle, the first focus control power and the second focus control power, calculate the optical sensitive parameter; And

When optical head moves to an ad-hoc location and goes forward side by side line focusing, write down the pairing focus control power of described ad-hoc location, and, calculate the optimum tilt angle of described ad-hoc location correspondence according to this focus control power and optical sensitive parameter, to adjust described inclination angle of optical head; The described optical sensitive parameter that calculates is:

Adopt following expression to calculate described optical sensitive parameter S:

S＝[Tilt(2)-Tilt(1)]/[FCO(2)-FCO(1)]；

Wherein, Tilt (2) is the described second optimum tilt angle, and Tilt (1) is the described first optimum tilt angle, and FCO (2) is the described second focus control power, and FCO (1) is the described first focus control power;

The described angle of inclination that calculates described ad-hoc location correspondence is:

Adopt following expression to calculate the angle of inclination Tilt (X) of described ad-hoc location correspondence:

Tilt(X)-Tilt(1)＝S×[FCO(X)-FCO(1)]；

Wherein, FCO (X) is the focus control power of described ad-hoc location correspondence.

Spirit of the present invention is to utilize a predetermined angular setting program, chooses 2 points on optical record medium, obtains the angle of inclination of each point respectively, meanwhile writes down 2 focus control power, calculates an optical sensitive degree at last in view of the above.When reading or during burning data, obtain and read or the current focus control power value of the point of burning data,, calculate pairing angle of inclination according to optical sensitive parameter and the focus control power obtained, revise the angle of inclination of optical head in real time, guarantee to read or the burning data steady quality.Because the present invention's demand at least gets 2 optimum tilt angle, therefore, can save the time of slant correction.If adopt conventional practice in the past,, need to calculate the optimum tilt angle of multiple spot for overcoming the disc angle of inclination from inside to outside and nonlinearities change; Perhaps, then only make minority for saving time what time, linear interpolation then can not the true angle of inclination of complete reaction.In comparison, the present invention had not only saved time but also can the real angle of inclination of real time reaction, thereby solved in the prior art to the discs recorded information effectively or read the problem of quality of information shakiness from discs.

Description of drawings

Fig. 1 is the Organization Chart of prior art medium dip adjusting gear.

Fig. 2 is the structural drawing that does not need the optical pickup tilt angle Adjustment System of angle detection in the prior art.

Fig. 3 is the synoptic diagram of the disclosed inclination angle of optical head modification method of application documents of US2005/0117473 for U.S. Patent Publication No..

Fig. 4 is the process flow diagram of inclination angle of optical head method of adjustment in the embodiment of the invention.

Fig. 5 is the synoptic diagram of the method for adjustment of inclination angle of optical head in the embodiment of the invention.

The primary clustering symbol description

10,32: optical head 16: object lens 18: rotating shaft

12: optical transmitting set 14a, 14b: optical receiver 20: tilt control module

22: regenerated signal generation unit 23: jitter detector

24: tilt control unit 25: tilt drive

26: internal storage location P1, P2: position

31: discs S401～S410: the step of the embodiment of the invention

P501, P502: the position of discs

Tilt (A): the first optimum tilt angle of P501 position correspondence

Tilt (B): the second optimum tilt angle of P502 position correspondence

FCO (A): the first focus control power of P501 position correspondence

FCO (B): the second focus control power of P502 position correspondence

Embodiment

Fig. 4 is the process flow diagram of the method for adjustment of the inclination angle of optical head that illustrates according to the embodiment of the invention.Fig. 5 is the synoptic diagram of the method for adjustment of the inclination angle of optical head that illustrates according to the embodiment of the invention.Please also refer to Fig. 4 and Fig. 5, the method for adjustment of this inclination angle of optical head comprises the following step:

Step S401: beginning.

Step S402: optical head is moved to the primary importance of optical record medium, and start focusing function.As shown in Figure 5, optical read head is moved to the P501 position earlier, and focuses in this position.Wherein, optical record medium is the discs that optical head reads information or writing information.

Step S403: ask for the focus control power of optical head, be designated as the first focus control power in primary importance.The method of asking for focus control power is a known technology, does not encyclopaedize at this.

Step S404: change the angle of inclination of optical head,,, be designated as the first optimum tilt angle to ask for the optimum tilt angle of optical head in primary importance by the light beam of sensing reflection on optical record medium.In general, ask for the optimum incline angle degree, can be by changing the angle of inclination of optical head, and detect the push-pull signal of each angle of inclination correspondence, this push-pull signal for example is main beam push-pull signal (MainBean Push Pull, MPP) or inferior push-pull signal (SPP) or difference push-pull signal (DPP), will produce the peaked angle of inclination of this push-pull signal, as the optimum tilt angle of trying to achieve.In general, when push-pull signal generation maximal value, the angle of inclination of this moment is best.

Step S405: optical head is moved to the second place of optical record medium, and start focusing function.As shown in Figure 5, in this step, optical read head is moved to the P502 position, and focuses in this position.

Step S406: ask for the focus control power of optical head, be designated as the second focus control power in the second place.

Step S407: change the angle of inclination of optical head,,, be designated as the second optimum tilt angle to ask for the optimum tilt angle of optical head in the second place by the light beam of sensing reflection on optical record medium.Identical with step S404 obtains the optimum tilt angle on the P501 position mode in this step in the mode of obtaining the optimum tilt angle on the P502 position.

Step S408:, calculate an optical sensitive parameter according to the first optimum tilt angle, the second optimum tilt angle, the first focus control power and the second focus control power.At this, the mathematical notation formula that defines above-mentioned optical sensitive parameter is as follows:

$S\left(\mathrm{Sensitixity}\right)=[\mathrm{Tilt}\left(B\right)-\mathrm{Tilt}\left(A\right)]/[\mathrm{FCO}\left(B\right)-\mathrm{FCO}\left(A\right)]=\frac{\mathrm{\ΔTilt}}{\mathrm{\ΔFCO}};$

Wherein, S represents the optical sensitive parameter; The first optimum tilt angle of Tilt (A) expression P501 position correspondence; The second optimum tilt angle of Tilt (B) expression P502 position correspondence; The focus control power of FCO (A) expression P501 position correspondence; The focus control power of FCO (B) expression P502 position correspondence, △ Tilt is the difference of above-mentioned Tilt (B) and Tilt (A), △ FCO represents the difference of FCO (B) and FCO (A).Only for illustrating, △ Tilt also can be [Tilt (A)-Tilt (B)] to above mathematical expression, and this moment, △ FCO then was [FCO (A)-FCO (B)].

In addition, in another embodiment of the present invention, when utilizing position more than 2 and corresponding focus control power and angle of inclination to ask for the optical sensitive parameter, then can try to achieve wantonly photaesthesia parameter at 2 to step S408, obtain an average photaesthesia parameter then according to aforesaid way step S402.In this case, after step S408, before the step S409, also need optical head is moved to other positions of optical record medium, according to the optimum tilt angle and the focus control power calculating optical sensitive parameter of any two positions; Then, obtain the mean value of each the optical sensitive parameter that calculates, as carrying out the optical sensitive parameter that inclination angle of optical head is proofreaied and correct among the step S409.

Step S409: reading information from optical record medium or during to the optical record medium recorded information, the optical sensitive parameter that adopts step S408 to obtain is carried out the correction of inclination angle of optical head.

In this step, read or the burning data process in, read focus control power FCO (X) value on the ad-hoc location X, next utilize above-mentioned optical sensitive parameter S of trying to achieve and desire the pairing focus control power of correction position X FCO (X), calculate desire the angle of inclination Tilt (X) of correction position X correspondence, its mathematical notation formula is as follows:

Tilt(X)-Tilt(A)＝S×[FCO(X)-FCO(A)]，

Wherein, the first optimum tilt angle of Tilt (A) expression P501 position correspondence; The focus control power of FCO (A) expression P501 position correspondence.X is current reading or the point of burning data on the optical record medium, also is the point of desiring the correct tilt angle.

Therefore, can revise the angle of inclination of optical head in real time, make and to read or the steady quality of burning data.

Step S410: finish.

It should be noted that, though it is a linear equation that the mathematical notation formula of asking for of above-mentioned optical sensitive parameter shows, the mathematical notation formula of the correction at angle of inclination also is a linear equation, but, focus control power can change along with the warpage of discs, because discs and nonlinear straight line, therefore the focus control power that is measured and non-linear.Therefore, in an embodiment of the present invention,, also can reach nonlinear correction, just be similar to the correction of curved surface even only measure the optimum tilt angle and the focus control power of P501 position and P502 position respectively.As seen, the situation of the approaching more real discs warpage of the correcting mode of the embodiment of the invention.

With respect to prior art, if the angle of inclination that prior art need overcome disc from inside to outside and the situation of nonlinearities change, need many different positions on the measuring light disc, ask for the more optimum tilt angle of multiple spot, this kind mode will expend many times; If save time, only do minority some, do correction in the mode of linear interpolation, this mode can not be as the real angle of inclination of reaction as described in the embodiment of the invention.In comparison, the present invention only need detect 2 points, not only saves time but also can the real angle of inclination of real time reaction.

In the above-described embodiments, though be to give an example with main beam push-pull signal (MPP), inferior push-pull signal (SPP) and difference push-pull signal (DPP), but it will be appreciated by those skilled in the art that still has other signal can be utilized as the signal of asking for the optimum tilt angle.Therefore the present invention is not exceeded with above-mentioned signal.

The specific embodiment that is proposed in the detailed description of preferred embodiment is only in order to convenient explanation technology contents of the present invention, but not with narrow sense of the present invention be limited to the foregoing description, under the situation that does not exceed the present invention's spirit and principle, the many variations of being done is implemented, and all belongs to scope of the present invention.

Claims (4)

1. the method for adjustment of an inclination angle of optical head is characterized in that, this method comprises:

Flying optical head is to the primary importance of distance one optical record medium, the line focusing of going forward side by side; Obtain the focus control power at primary importance place, be designated as the first focus control power, and the optimum tilt angle of obtaining the primary importance place, be designated as the first optimum tilt angle;

Move the second place of described optical head, the line focusing of going forward side by side to described optical record medium; Obtain the focus control power at second place place, be designated as the second focus control power, and the optimum tilt angle of obtaining second place place, be designated as the second optimum tilt angle;

According to the described first optimum tilt angle, the second optimum tilt angle, the first focus control power and the second focus control power, calculate the optical sensitive parameter; And

When optical head moves to an ad-hoc location and goes forward side by side line focusing, write down the focus control power of described ad-hoc location correspondence, and, calculate the angle of inclination of described ad-hoc location correspondence, to adjust described inclination angle of optical head according to this corresponding focus control power and optical sensitive parameter;

The described optical sensitive parameter that calculates is:

Adopt following expression to calculate described optical sensitive parameter S:

S＝[Tilt(2)-Tilt(1)]/[FCO(2)-FCO(1)]；

Wherein, Tilt (2) is the described second optimum tilt angle, and Tilt (1) is the described first optimum tilt angle, and FCO (2) is the described second focus control power, and FCO (1) is the described first focus control power;

The described angle of inclination that calculates described ad-hoc location correspondence is:

Adopt following expression to calculate the angle of inclination Tilt (X) of described ad-hoc location correspondence:

Tilt(X)-Tilt(1)＝S×[FCO(X)-FCO(1)]；

Wherein, FCO (X) is the focus control power of described ad-hoc location correspondence.

2. the method for claim 1 is characterized in that, the obtaining step of described optimum tilt angle comprises:

Change the angle of inclination of described optical head, detect the push-pull signal of each angle of inclination correspondence;

The angle of inclination of correspondence is as described optimum tilt angle during with push-pull signal generation maximal value.

3. the method for claim 1, it is characterized in that, described calculating after the optical sensitive parameter, this method further comprises: move described optical head other positions to described optical record medium, according to the optimum tilt angle and the focus control power calculating optical sensitive parameter of any two positions;

Obtain the mean value of each the optical sensitive parameter that calculates, as the optical sensitive parameter at the angle of inclination of calculating described ad-hoc location correspondence.

4. method as claimed in claim 2 is characterized in that, described push-pull signal is: main beam push-pull signal or inferior push-pull signal or difference push-pull signal.

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