CN100373473C - Optical disc controller - Google Patents

Abstract

An optical disc controller capable of drawing focus in a short time for the target information plane of an optical disc having a plurality of information planes. An objective lens is brought close to the optical disc having a plurality of information planes by the output signal from a driving signal generating circuit. When a focus point passage detecting circuit detects passage of a first focus position and the objective lens is brought closer from that position to the optical disc by a specified amount, an n-revolution delay circuit outputs a reversal command f. After the objective lens was withdrawn from the optical disc while altering the orientation thereof, a focus drawing circuit switches a signal (a) being delivered to an actuator drive circuit from the driving signal generating circuit to a control circuit output signal and actuates the control circuit to draw the focus.

Description

Optical disc controller

Technical field

The present invention relates to that light source such as a kind of use laser records optically with signal that information carrier (CD) is gone up or from the optical disc controller of information carrier reproducing signal, be particularly related to the disk control unit that carries out focus control, this focus control is controlled the beams focusing point.

Background technology

In order to use light sources such as laser that information carrier is carried out recording of information/reproduction optically, need carry out focus control, make the information faces of information carrier always be in the focus of light beam (focus point) position.In order to realize this point, before focus control, carry out so-called focusing guiding action, the information faces of information carrier adjusted to the focal position of light beam by mobile object lens.

In addition, existing optical disc controller is by shortening distance between information carrier and object lens, being so-called operating distance (working distance is designated hereinafter simply as WD), realize the miniaturization (for example, Japanese kokai publication hei 5-334687 communique) of light picker (pickup).

Below, with reference to Figure 14, Figure 15 and Figure 16 existing optical disc controller is described.

Figure 14 is the block diagram of the structure example of the existing optical disc controller of expression.

In Figure 14, the sawtooth signal that sawtooth signal generation circuit 45 output amplitudes increase gradually.Commutation circuit 31 is switched the output signal of sawtooth signal generation circuit 45 or the output signal of control circuit 20, and send to actuator (actuator) driving circuit 21 as signal a, actuator driving circuit 21 makes actuator 22 actions according to signal a, drives object lens 23 thus.

Focus error detection circuit 12 is circuit of focus error signal b of side-play amount of the information faces 2A of the focal position of output expression object lens 23 and CD 2, is described in greater detail in the back.Focus on the level judgement that steering circuit 32B carries out focus error signal b,, realize focusing on the guiding action thus to commutation circuit 31 output order g.

Figure 15 is the circuit diagram of inner structure example of the focus error detection circuit 12 of expression Figure 14.In Figure 15, focus error detection circuit 12 is by 4 district's photodetectors (4 cut apart photodetector) 301 in the light picker 3, according to the light beam spot 302 corresponding and detected signals of incident, by (A+D) and (B+C) the additive signal of 2 totalizers, 1201,1202 generations as the diagonal sum of 4 district's photodetectors 301, and then utilizing method of astigmatism (non-check and accept poor method) to generate focus error signal, this method of astigmatism is generated the differential signal of (A+C)-(B+D) by subtracter 1203.

Next, the focusing of the existing optical disc controller that constitutes like that more than illustrating with reference to Figure 16 guiding action.Figure 16 is the oscillogram of the each several part signal among Figure 14.

When from system controller 30 output focusing key instruction h, the sawtooth signal based on the amplitude from 45 outputs of sawtooth signal generation circuit changes successively drives object lens 23 by actuator driving circuit 21, actuator 22.The amplitude of this sawtooth signal increases gradually, when the focus of object lens 23 arrives information faces 2A, focusing on steering circuit 32F carries out from the level judgement of the focus error signal b of focus error detection circuit 12 outputs, reach the timing (timing) of guiding level at this level, to commutation circuit 31 output switching command g, the signal a that outputs to actuator driving circuit 21 is switched to the output signal of control circuit 20 from the output signal of saw-tooth wave generating circuit 45, and start-up control circuit 20 focuses on the guiding action thus.

Therefore such optical disc controller wants spended time owing to little by little increase the amplitude of sawtooth signal till detecting focus error signal, consequently focusing on the guiding action needs the time.

Particularly at the interval of CD and object lens during,, focus on to guide and move the needed time and further extend to the time lengthening that detects till the focus error signal because of sagging expansion of the face swing (surfaceoscillation) of CD or object lens.

In addition, have at CD under the situation of a plurality of information faces, can not discern the focus error signal which information faces detected focus error signal is, therefore exist and to focus on the such problem of guiding to the target information face.

Particularly the target information identity distance is many more from object lens detected focus error signal far away more, therefore is difficult to be directed to the target information face.

Summary of the invention

The present invention makes in view of the above problems, and its purpose is that the inside that is provided at CD has under the situation of a plurality of information faces, also can focus on the optical disc controller of guiding at short notice to the target information face.

To achieve these goals, optical disc controller of the present invention has following structure: comprise and assemble irradiation unit, focusing mobile device, focusing-error detecting device, focus point by pick-up unit, counter-rotating command device, driving signal generator, control device and focusing guiding (focusing imports) device.

Assembling irradiation unit shines beam convergence on the information carrier with a plurality of information faces by object lens.Focusing on mobile device moves the focus by the light beam of assembling the irradiation unit convergence by mobile object lens on the normal direction of the face of information carrier.Focusing-error detecting device generates the focus error signal corresponding to the offset of the focus of each face of information carrier with light beam.Focus point detects surface and each information faces that beams focusing point has passed through information carrier by pick-up unit.The counter-rotating command device uses from focus point and exports the counter-rotating instruction by the output signal of pick-up unit.Driving signal generator makes the signal of object lens near information carrier to focusing on mobile device output, and switches to according to the counter-rotating instruction and to make signal and the output of object lens away from information carrier.Control device uses focus error signal control to focus on mobile device, makes each information faces of focus point tracked information carrier.The focusing guiding device will move and switch to control device from driving signal generator, focus on the guiding action by focusing on mobile device.

According to this structure, object lens do not carry out knee-action repeatedly just can enter the guiding action at once, can shorten the guiding needed time of action.In addition, by making object lens, and after focus point passes through, change direction at once, can prevent object lens, under the narrow and small situation of the WD of object lens, can prevent that also object lens and information carrier from clashing unnecessarily near information carrier near information carrier.

In addition, optical disc controller of the present invention has following structure: from the output signal of driving signal generator make object lens near or switching point during away from information carrier, the inclination of drive waveforms is little by little changed.

According to this structure, can prevent that object lens from vibrating because of the retroaction that inertia causes, can always obtain stable focus error signal, and can not produce unsettled focus error signal, also can guarantee stability for focusing on the guiding action.

In addition, optical disc controller of the present invention has following structure: the information carrier with a plurality of information faces is carried out the aberration corresponding with the target information face set, according to the amplitude of focus error signal the target information face is differentiated.At this moment, be preferably based on focus error signal for greatly and the maximum value of the level of the level of the reflected light amount signal when minimum and reflected light amount signal, the phase relation of detection of focus error signal and reflected light amount signal is differentiated the target information face thus.

According to this structure, can correctly differentiate the focus error signal of target information face among a plurality of focus error signals, also can positively be directed to the target information face when focusing on guiding, above-mentioned a plurality of focus error signals are detected from the information carrier with a plurality of information faces.

In addition, optical disc controller of the present invention has following structure: when making object lens near the information carrier with a plurality of information faces, and when detecting the passing through of initial focus point position, make object lens from this position further to information carrier only near scheduled volume, after the change direction makes object lens away from information carrier, focus on the guiding action by focusing on guiding device.

According to this structure, by make object lens from initial focus point to information carrier only near scheduled volume, can prevent object lens unnecessarily near information carrier, can prevent also that when WD is narrow and small object lens and information carrier from clashing.In addition, whether the information carrier discriminant information face that there is no need having a plurality of information faces is target face, therefore can avoid clashing by differentiating wrong misguidance that causes and object lens and information carrier.In addition, even do not carry out the differentiation of information faces, amount of movement that also can be by regulating object lens, be scheduled volume, the target information face is focused on guiding.

In addition, optical disc controller of the present invention has following structure: by the focal position of sequence detection light beam that information carrier with a plurality of information faces is occurred according to the maximum value and the minimal value of focus error signal, differentiate the target information face.

According to this structure, can correctly differentiate the focus error signal of target information face among a plurality of focus error signals, also can be directed to the target information face reliably when focusing on guiding, above-mentioned a plurality of focus error signals are that to have the information carrier of a plurality of information faces internally detected.

In addition, optical disc controller of the present invention has following structure: comprise the face discriminating gear, it is the predetermined face that information carrier comprises by the detected face of pick-up unit that the information carrier with a plurality of information faces is differentiated by focus point; The amount of movement setting device is based on the amount of movement of setting object lens from the output signal of face discriminating gear; Amount of movement management pick-up unit B detects the scheduled volume B that only moves by the setting of amount of movement setting device by focus point after the focus point to focus point by pick-up unit and manages and detect; And the counter-rotating command device, use from the output signal of amount of movement management pick-up unit and export the counter-rotating instruction.

According to this structure, can determine that the face that the face discriminating gear determines is the information faces that information carrier inside has, owing to move to the target information face, therefore can reach the reliability that focuses on guiding and property rapidly from this information faces of having determined.

Description of drawings

Fig. 1 is the block diagram of a structure example of the optical disc controller that relates to of expression embodiment of the present invention 1.

Fig. 2 is the oscillogram of each several part signal of the optical disc controller of Fig. 1.

Fig. 3 A is the figure of the shape of the light beam spot 302 of each point on 4 district's photodetectors 301 of the S character waveform of the focus error signal b of Fig. 1 when being illustrated in no spherical aberration.

Fig. 3 B is the figure of shape of the light beam spot 302 of each point on 4 district's photodetectors 301 of S character waveform of the focus error signal b of Fig. 1 when being illustrated in spherical aberration.

Fig. 4 is the block diagram of a structure example of the optical disc controller that relates to of expression embodiment of the present invention 2.

Fig. 5 is the oscillogram of the each several part signal of the Fig. 4 when the rotating ratio of CD is very fast.

Fig. 6 is the oscillogram of the each several part signal of the Fig. 4 when the rotating speed of CD is slow.

Fig. 7 is the block diagram of a structure example of the optical disc controller that relates to of expression embodiment of the present invention 3.

Fig. 8 A is the figure of explanation relation of the S character waveform of the focus error signal b of Fig. 7 and reflected light amount signal c when no spherical aberration.

Fig. 8 B is the figure of explanation relation of the S character waveform of the focus error signal b of Fig. 7 and reflected light amount signal c when spherical aberration is arranged.

Fig. 9 is the oscillogram (when for example, the rotating ratio of CD is very fast etc.) of each several part signal of the optical disc controller of Fig. 7.

Figure 10 is the block diagram of a structure example of the optical disc controller that relates to of expression embodiment of the present invention 4.

Figure 11 is the oscillogram of each several part signal of the optical disc controller of Figure 10.

Figure 12 is the block diagram of a structure example of the optical disc controller that relates to of expression embodiment of the present invention 5.

Figure 13 is the oscillogram of the each several part signal of Figure 12 when CD has the face swing.

Figure 14 is the block diagram of the structure example of the existing optical disc controller of expression.

Figure 15 is the circuit diagram of inner structure of the focus error detection circuit 12 of expression Figure 14.

Figure 16 is the oscillogram of each several part signal of the optical disc controller of Figure 14.

Embodiment

Followingly explain preferred implementation of the present invention with reference to accompanying drawing.

(embodiment 1)

Fig. 1 is the block diagram of a structure example of the optical disc controller that relates to of expression embodiment of the present invention 1.In Fig. 1, give prosign for the textural element identical, and omit its explanation with conventional example.

In Fig. 1, dish 1 is 2 layer laminate dishes with the 1st information faces 1A and the 2nd information faces 1B.The output of 63 pairs of system controllers of aberration setting apparatus, 30 specified message faces does not produce the aberration setting value of spherical aberration to light beam.The spherical aberration that aberration regulator 65 is regulated beam focus according to the setting value of aberration setting apparatus 63 via aberration regulator driving circuit 64.

Reflection light quantity testing circuit 41 output with from coiling the proportional signal of light quantity (hereinafter referred to as the reflected light amount signal) c of 1 reflection.Focus point passes through pick-up unit 44 under the condition of reflected light amount signal c more than or equal to predetermined value Clvl from reflection light quantity testing circuit 41, identification is from the S character waveform of the focus error signal b of focus error detection circuit 12 output, detects to having passed through focus point under less than the condition of predetermined value Clvl at reflected light amount signal c.

Amplitude detecting circuit 62 passes through the focus point of testing circuit 44 outputs by signal d, the amplitude of the S character waveform of detection of focus error detection signal b based on focus error signal b with from focus point.Information faces testing circuit 61 from the signal output of focus point by testing circuit 44 time, if from the amplitude of amplitude detecting circuit 62 outputs greater than predetermined value Bcmp, then detect information faces for the target of having passed through to want channeling conduct.

It is under the situation of target information face that characteristic correction circuit 43 detects at information faces testing circuit 61, according to the amplitude b1A of the S character waveform of exporting from amplitude detecting circuit 62 and the ratio of reference value Bstd, the gain setting of control circuit 20 is revised.

Passed through the target information face if information faces testing circuit 61 detects, the instruction circuit 40 that then reverses is to focusing on steering circuit 32A and drive signal generation circuit 42A output counter-rotating instruction f.Drive signal generation circuit 42A output make object lens 23 near or situation away from the signal of dish 1 under, the inclination of drive waveforms does not sharply change ground, gently changes the output signal obliquely of drive waveforms, when starting h by system controller 30, output makes object lens 23 in initial drive signal away from dish 1 in during certain, change direction then, output is near the drive signal of dish 1.Focus on steering circuit 32A,, and be under the condition of inverted status, carry out the level of focus error signal b and judge, and, realize focusing on the guiding action thus to commutation circuit 31 output order g at counter-rotating instruction circuit 40 output counter-rotating instruction f.

Next, the action of the disk control unit that constitutes like that more than illustrating with reference to Fig. 1, Fig. 2 and Fig. 3.

Fig. 2 is the oscillogram of each several part signal of the optical disc controller of Fig. 1.Send the information that focuses on key instruction h and target information face (being the 1st information faces 1A in the present embodiment) to drive signal generation circuit 42A and aberration setting apparatus 63 respectively from system controller 30.Aberration setting apparatus 63 is adjusted aberration adjuster 65, makes the 1st specified information faces 1A is not produced spherical aberration.Simultaneously, drive signal generation circuit 42A output makes the drive signal of object lens 23 away from the direction of dish 1, makes the inclination of drive waveforms not change sharp.Drive signal generation circuit 42A switches to and makes the drive signal of object lens 23 near the direction of dish 1 making object lens 23 away from after coiling 1 scheduled volume, makes the inclination of drive waveforms not change sharp.When object lens 23 during near dish 1, its focus point is by the 2nd information faces 1B, from the S character waveform b1 of focus error detection circuit 12 output focus points by the 2nd information faces 1B.

At this, S character waveform when explanation does not produce spherical aberration with reference to Fig. 3 A and Fig. 3 B and the S character waveform when having produced spherical aberration.Fig. 3 A and Fig. 3 B be when representing not produce spherical aberration respectively and 4 district's photodetectors 301 of the each point of the S character waveform when having produced spherical aberration on the figure of shape of light beam spot 302.

As shown in Figure 3A, when not producing spherical aberration, be thin-line-shaped at the peak of S character waveform and paddy place light beam spot 302.Relative therewith, shown in Fig. 3 B, when having produced spherical aberration, at the central portion and the peripheral part of object lens 23, the centralized system difference of light beam, so the light intensity create a difference (the light beam spot 302a of central portion, the light beam spot 302b of peripheral part) in the light beam spot.And the peak of S character waveform does not become thin-line-shaped with the shape of the light beam spot at paddy place.Therefore, the peak of S character waveform and the absolute value of paddy diminish, and diminish as its amplitude of S character waveform.

Like this, amplitude is that spherical aberration diminishes because of having produced, the amplitude (b1B) of the S character waveform b1 of the 2nd information faces 1B is compared with the predetermined value (Bcmp) that is input to information faces testing circuit 61, and to be judged as it be not the target information face.When object lens 23 further near dish 1 the time, its focus point is by the 1st information faces 1A, from the S character waveform b2 of focus error detection circuit 12 output focus points by the 1st information faces 1A.Information faces testing circuit 61 is the same during with the 2nd information faces 1B, according at the amplitude (b1A) of focus point by the detected S character waveform of the timing b2 of signal d greater than predetermined value (Bcmp), the waveform that to be judged as this S character waveform be the target information face.

When information faces testing circuit 61 detects target information face (being the 1st information faces 1A in the present embodiment), counter-rotating instruction circuit 40 will reverse and instruct f to output to focusing steering circuit 32A and drive signal generation circuit 42A.Drive signal generation circuit 42A accepts the counter-rotating instruction, switches to make the drive signal of object lens 23 away from the direction of dish 1, makes the inclination of drive waveforms not change sharp.Simultaneously, when detecting information faces, characteristic correction circuit 43 will compare with reference amplitude value (Bstd) from the amplitude (b1A) to the S character waveform b2 of the 1st information faces 1A of amplitude detecting circuit 62 output, and according to this than the gain adjustment of carrying out control circuit 20, make to focus on ride gain after the guiding become suitable.Simultaneously, the focusing steering circuit 32A that has accepted counter-rotating instruction f becomes the state that can carry out the guiding action judged based on the level of focus error signal b.

When object lens 23 move to the direction away from dish 1, and during from focus error detection circuit 12 output S character waveform b3, focus on the level judgement that steering circuit 32A carries out focus error signal b (b3), the timing that reaches the guiding level at this level is to commutation circuit 31 output switching command g, the signal a that outputs to actuator driving circuit 21 is switched to the output signal of control circuit 20 from the output signal of drive signal generation circuit 42A, and focus on the guiding action by start-up control circuit 20.

As mentioned above, according to present embodiment, output signal from drive signal generation circuit 42, make object lens 23 away from after dish 1 scheduled volume, change direction and approaching dish 1, when detecting the focus point position from focus error signal by the target information face, drive, make and change direction at once, away from dish 1, then, use the focus error signal that produces to focus on the guiding action, object lens 23 do not carry out knee-action repeatedly and just can enter guiding action at once thus, can shorten to guide and move the needed time.And then, make object lens 23 near dish 1, after passing through, focus point changes direction at once, can prevent object lens 23 thus unnecessarily near dish 1, can prevent also that when WD is narrow and small object lens 23 and dish 1 from clashing.

When the S character waveform that detects the target information face, characteristic correction circuit 43 carries out optimization according to this amplitude to the gain of control circuit 20, only learns the S amplitude thus and just can further shorten the time that focuses on the guiding action, and there is no need to drive object lens 23.

In addition, focus point by testing circuit 44 in order to detect passing through of focus point position, to use with focus error signal from the reflected light amount signal of reflection optical detection circuit 41, remove the noise of focus error signal thus, carry out reliable focus point and detect, can realize stable focusing guiding action like this.

In addition, when the output signal of drive signal generation circuit 42A changes the moving direction of object lens 23, the inclination of drive waveforms is little by little changed, make the inclination of its drive waveforms not change sharp, can prevent object lens 23 vibrations thus, do not produce unsettled focus error signal, can positively realize focusing on the guiding action with stable focus error signal.

In addition, dish 1 with a plurality of information faces is used the aberration of aberration regulator 65 control bundle, and setting light beam, make and do not produce spherical aberration on the target information face, can differentiate the target information face according to the amplitude of the S word signal of focus error signal b thus, can differentiate the target information face to dish 1 with simple structure, this information faces is focused on guiding reliably with a plurality of information faces.

In the present embodiment, drive signal generation circuit 42 drives, make object lens 23 at first away from the dish 1, but, be not limited to present embodiment, the size of the face swing of the position of the object lens 23 in the time of also can utilizing beginning and dish 1 drives, and makes object lens 23 at once near dish 1.

(embodiment 2)

Fig. 4 is the block diagram of a structure example of the optical disc controller that relates to of expression embodiment of the present invention 2.In Fig. 4,, give prosign and omit its explanation for the textural element identical with conventional example and embodiment 1.

In Fig. 4, constant calculations circuit 71, focus point by testing circuit 44 after detecting initial S character waveform, to calculate the actuating speed Vlns of rotation wait revolution n that in n returns slow circuit 70, sets and the object lens of in drive signal generation circuit 42A, setting 23 with following formula (1) and formula (2) near the distance L of CD 1 and the rotating speed Vrot of coil motor 24 based on object lens 23.

n＝K×L×Vrot …(1)

Vlns＝(L×Vrot)/n …(2)

In above-mentioned formula (2), K is used to make actuating speed Vlns convergence constant within the specific limits.

Especially, the result of formula (1) is rounded to integer, obtains rotation and wait for revolution n.At this, as preset distance L, guarantee to move to the 1st information faces 1A from surperficial 1C the distance that object lens 23 must move for the focus that makes object lens 23 at least.

N return slow circuit 70 based on focus error signal b and focus point by signal d, after CD 1 changes from the zero cross point rotation n of initial S character waveform, to drive signal generation circuit 42A output counter-rotating instruction f.Drive signal generation circuit 42B output make object lens 23 away from or near the signal of CD 1, object lens 23 are set by aforementioned calculation circuit 71 near the speed of CD 1.Focus on steering circuit 32B,, carry out the level of focus error signal b and judge, to commutation circuit 31 output order g, realize focusing on the guiding action thus according to its judged result at return slow circuit 70 output counter-rotating instruction f and being under the condition of inverted status of n.

Then, for the action of above such optical disc controller that constitutes, describe with reference to Fig. 4, Fig. 5 and Fig. 6.

Fig. 5 is the oscillogram at the each several part signal of the rotating speed Vrot of CD 1 Fig. 4 when very fast.

At first, focus on key instruction h and send to drive signal generation circuit 42B from system controller 30.Simultaneously, constant calculations circuit 71 with the rotating speed Vrot of CD 1 at this moment, uses above-mentioned formula (1) and formula (2) to calculate the speed Vlns that waits for revolution n (=3) and object lens 23, sets respectively in n returns slow circuit 70 and drive signal generation circuit 42B.

Drive signal generation circuit 42B output drive signal, make object lens 23 with the actuating speed Vlns that sets by constant calculations circuit 71 near CD 1.When object lens 23 during near CD 1, its focus is by the surperficial 1C of CD 1, from focus error detection circuit 12 output consequent S character waveforms (b1).The n slow circuit 70 of returning is a starting point with the zero cross point of initial S character waveform b1, times that CD 1 rotation 3 is changeed (between this, output is to the S character waveform b2 of the 2nd information faces 1B, to the S character waveform b3 of the 1st information faces 1A) afterwards, output counter-rotating instruction f.Object lens 23 were to 1 timing near preset distance L of CD after this was equivalent to detect initial S character waveform b1.

The return counter-rotating instruction f of slow circuit 70 outputs of n is input to and focuses on steering circuit 32B and drive signal generation circuit 42B.Drive signal generation circuit 42B accepts the counter-rotating instruction, switches to and makes the drive signal of object lens 23 away from the direction of CD 1.Simultaneously, the focusing steering circuit 32B that has accepted counter-rotating instruction f becomes the state that can carry out the guiding action judged based on the level of focus error signal b.

In addition, when object lens 23 move to the direction away from CD 1, during from focus error detection circuit 12 output S character waveforms (b4), focus on the level judgement that steering circuit 32B carries out focus error signal b, the timing that reaches the guiding level at this level is to commutation circuit 31 output switching command g, the signal a that outputs to actuator driving circuit 21 is switched to the output signal of control circuit 20 from the output signal of drive signal generation circuit 42B, and, carry out focusing guiding action to the 1st information faces 1A by start-up control circuit 20.

Fig. 6 is the oscillogram of the each several part signal of the Fig. 4 when the rotating speed Vrot of CD 1 is slow.

To elemental motion from the guiding of the focusing key instruction h of system controller 30, is identical with the rotating speed Vrot of CD 1 when very fast, therefore but the rotating speed Vrot of CD 1 is slow, and rotation waits for that revolution n changes to 2 from 3, and sets the speed Vlns of corresponding with it object lens 23.In addition, even this moment, object lens 23 were to 1 timing near preset distance L of CD after output counter-rotating instruction f also was equivalent to detect initial S character waveform b1.

As mentioned above, in the present embodiment, to make the distance L of object lens 23 by constant calculations circuit 71 according to the rotating speed Vrot of CD 1 with after detecting initial S character waveform b1, calculate that revolution n is waited in the rotation of setting and the actuating speed Vlns of the object lens 23 set in n returns slow circuit 70 in drive signal generation circuit 42B near CD 1.Thus, object lens 23 do not carry out knee-action repeatedly just can enter the guiding action at once, therefore can shorten the guiding needed time of action.In addition, make object lens 23 near CD 1, from initial S character waveform b1 to 1 of CD near the moment of preset distance L, change the direction of object lens 23, thus, object lens 23 need not can prevent also that when WD is narrow and small object lens 23 and CD 1 from clashing unnecessarily near CD 1.

In addition, change the direction of object lens 23, the timing that makes the level judgement that begins focus error signal b for guiding is the zero crossing rotation n commentaries on classics back (n be integer) of CD 1 from initial S character waveform b1, thus, even have at CD 1 under the situation of face swing composition, when the level of beginning focus error signal b is judged, can guarantee also that focus is certain to lean on the lining than the 1st information faces 1A, focus on guiding to information faces 1A reliably.

In addition, wait for revolution n and lens translational speed Vlns according to the rotating speed Vrot calculating rotation of CD 1, thus, even the rotating speed Vrot difference of CD 1 also can make lens translational speed Vlns roughly keep constant, the stability in the time of therefore guaranteeing to focus on guiding.And, also can always object lens 23 be remained preset distance L from the amount of movement that initial S character waveform detects after CD 1 rotation n changes, can avoid object lens 23 unnecessarily near CD 1.In addition, object lens 23 ground that can not stop drive, and therefore can reduce the speed switching point, can will be suppressed to bottom line by the bad influence that rocking of object lens 23 brought.

In addition, when focus point detects passing through of focus point position by testing circuit 44, by using focus error signal b and from the reflected light amount signal c of reflection light quantity testing circuit 41, remove the noise of focus error signal b, carry out reliable focus point and detect, can realize stable focusing guiding thus.

In the present embodiment, with drive signal generation circuit 42B as object lens 23 are illustrated its circuit that drives near the direction of CD 1 from initial.But the present invention is not limited to this, can consider that also the face swing etc. of CD 1 drives, and makes object lens 23 change direction afterwards, and drive only away from CD 1 preset distance initial, makes near CD 1.

In addition, remain the method for preset distance L, can be following structure also, and be not limited to present embodiment as the amount of movement that makes object lens 23.That is, make lens translational speed Vlns constant, and irrelevant with the rotating speed Vrot of CD 1, after 23 mobile preset distance L of object lens, before CD 1 rotation n changes, be parked in this position, detect CD 1 rotation n commentaries on classics from initial S character waveform after, change direction.Equally, rotation waits for that revolution n also can irrespectively set with rotating speed Vrot, and is not limited to present embodiment.

(embodiment 3)

Fig. 7 is the block diagram of a structure example of the optical disc controller that relates to of expression embodiment of the present invention 3.In Fig. 7,, give prosign and omit its explanation for the textural element identical with conventional example, embodiment 1 and embodiment 2.

In Fig. 7, maximum value/and minimal value testing circuit 80 under the condition of reflected light amount signal c more than or equal to predetermined value Clvl from reflection light quantity testing circuit 41, detect maximum value and minimal value from the focus error signal b of focus error detection circuit 12.Reflection light quantity difference detecting circuit 81 detects maximum value and minimizing separately timing at maximum value/minimal value testing circuit 80, detects the level difference Δ V from the reflected light amount signal c of reflection light quantity testing circuit 41.Maximum value detecting circuit 82 always detects the maximal value from the reflected light amount signal c of reflection light quantity testing circuit 41 in advance, in the timing of passing through detection signal d from focus point by testing circuit 44 output focus points, determine this maximal value, and this maximum value information is sent to positive naturalization circuit (normalizing circuit: positive naturalization circuit) 83.Positive naturalization circuit 83 carries out positive naturalization by using from the maximal value Vmax of maximum value detecting circuit 82 divided by the level difference Δ V from the reflection light quantity of reflection light quantity difference detecting circuit 81.Whether information faces judging circuit 84 is differentiated corresponding with the target information face by comparing from the positive naturalization reflection light quantity difference and the predetermined value Ncmp of positive naturalization circuit 83.The timing of counter-rotating instruction circuit 40 which output signal early in the output signal of the slow circuit 70 of returning from n with in from the output signal of information faces judging circuit 84, output counter-rotating instruction f, and send to focusing steering circuit 32C and drive signal generation circuit 42C.

The action of above-mentioned such optical disc controller that constitutes then, is described with reference to Fig. 7, Fig. 8 and Fig. 9.

Fig. 8 A and Fig. 8 B are the figure that the relation of the S character waveform of the focus error signal b when no spherical aberration and when spherical aberration is arranged and reflected light amount signal c is described respectively.Fig. 9 is the oscillogram (for example, the rotating speed Vrot of CD 1 when very fast etc.) of each several part signal of the optical disc controller of Fig. 7.

In Fig. 9, at first send to drive signal generation circuit 42C and focus on key instruction h from system controller 30.Aberration setting apparatus 63 is regulated aberration via aberration regulator driving circuit 64 by aberration regulator 65, makes the 1st specified information faces 1A is not produced spherical aberration.In addition, drive signal generation circuit 42C output makes object lens 23 with the drive signal of lens translational speed Vlns near the direction of CD 1, and this lens translational speed Vlns uses the formula (1) and the formula (2) of explanation in embodiment 2 to calculate by constant calculations circuit 71.When object lens 23 during near CD 1, its focus is by surperficial 1C and the 2nd information faces 1B, and from focus error detection circuit 12 consequent waveform b1 of output and b2.

At this, S character waveform when explanation does not produce spherical aberration with reference to Fig. 8 A and Fig. 8 B and the S character waveform when having produced spherical aberration.

Fig. 8 A shows the shape of the light beam spot 302 on 4 district's photodetectors 301 of each point of S character waveform when not producing spherical aberration, and when no spherical aberration, at the Feng Hegu of S character waveform, light beam spot 302 is thin wire.Fig. 8 B shows the shape of the light beam spot on 4 district's photodetectors 301 of each point of S character waveform when having produced spherical aberration.When having produced spherical aberration, because different with the centralized system of outer circumferential side light beam in interior all sides of object lens 23, therefore the light intensity in light beam spot will produce deviation (the light beam spot 302a of interior all sides, the light beam spot 302b of outer circumferential side).And the peak of S character waveform does not become thin wire with the shape of the light beam spot at paddy place.Particularly when having reduced 4 district photodetectors 301, locating light beam spot in the paddy (perhaps peak) of S character waveform will overflow from 4 district's photodetectors 301.On the other hand, in the peak of S character waveform (perhaps paddy) side, even in the position of further leaving zero cross point, the also state that does not overflow from 4 district's photodetectors 301.That is the phase shifting of the projection of the S character waveform of focus error signal b and reflected light amount signal c.

Like this, for surperficial 1C that has produced spherical aberration and the 2nd information faces 1B, the phase shifting of S character waveform and reflected light amount signal c.Maximum value/minimal value testing circuit 80 (Fig. 7) detects the peak of these S character waveforms and the timing of paddy, and reflection light quantity difference detecting circuit 81 calculates at separately the timing level difference Δ V from the reflected light amount signal of reflection light quantity testing circuit 41.When focus point detected passing through of S character waveform by testing circuit 44, maximum value detecting circuit 82 was determined maximal value Vmax, and sends to positive naturalization circuit 83.Positive naturalization circuit 83 utilizes Δ V and Vmax to calculate positive naturalization data N (=Δ V/Vmax), information faces judging circuit 84 compares positive naturalization data N (N2 of Fig. 8 B) and predetermined value Ncmp, because N2 〉=Ncmp, it is not corresponding with the 1st information faces 1A that becomes target therefore to be judged as this S character waveform.

In addition, as shown in Figure 9, when object lens 23 during further near CD 1, its focus point is by the 1st information faces 1A, and from the consequent S character waveform b3 of focus error detection circuit 12 outputs.Identical with the situation of surperficial 1C and the 2nd information faces 1B, maximum value/minimal value testing circuit 80, reflection light quantity difference detecting circuit 81 and maximum value detecting circuit 82 actions, information faces judging circuit 84 will compare with predetermined value Ncmp from the positive naturalization data N (N1 of Fig. 8 A) of positive naturalization circuit 83, therefore Nl＜Vcmp, it is corresponding with target information face 1A to be judged as this S character waveform.

Be sent to counter-rotating during instruction circuit 40 when information faces judging circuit 84 having been detected the 1st information faces 1A that becomes target, the return counter-rotating instruction of slow circuit 70 is the situations that also do not arrive from n, and the counter-rotating instruction circuit 40 instruction f1 that will reverse outputs to focusing steering circuit 32C and drive signal generation circuit 42C.Drive signal generation circuit 42C accepts counter-rotating instruction f1, and switches to and make the drive signal of object lens 23 away from the direction of CD 1.Simultaneously, the focusing steering circuit 32C that has accepted counter-rotating instruction f1 becomes the state that can carry out the focusing guiding action judged based on the level of focus error signal b.

In addition, object lens 23 move on away from the direction of CD 1, when from focus error detection circuit 12 output S character waveform b4, focus on the level judgement that steering circuit 32C carries out focus error signal b, reach the timing that guides level at this level,, the signal a that outputs to actuator driving circuit 21 is switched to the output signal of control circuit 20 from drive signal generation circuit 42C to commutation circuit 31 output switching command g1, and start-up control circuit 20 focuses on the guiding action thus.

On the other hand, in the present embodiment, also the same with embodiment 2, has the n slow circuit 70 of returning, in n returns slow circuit 70, set by constant calculations circuit 71 and wait for revolution n according to the rotation that the rotating speed Vrot of CD 1 uses formula (1) to calculate, after the time delay of the zero crossing rotation n commentaries on classics of initial detected S character waveform b1, provide output signal at CD 1 to counter-rotating instruction circuit 40.The information faces of counter-rotating instruction circuit 40 in information faces judging circuit 84 differentiated suitably action, and imported under the situation of counter-rotating instruction, ignores the return input of slow circuit 70 from n.But, information faces in information faces judging circuit 84 is differentiated former thereby can not suitably move because of the noise that reflected light amount signal c comprised etc., and under the situation of input counter-rotating instruction, be used to the return input signal output counter-rotating instruction f2 of slow circuit 70 from n.About later action, since the same with embodiment 2, explanation therefore omitted.

As mentioned above, in the present embodiment, the output signal of drive signal generation circuit 42C makes object lens 23 near CD 1, calculate the level difference of reflected light amount signal in the timing of the peak of focus error signal b and paddy, by will value and the predetermined value that it has carried out positive naturalization being compared, detect the target information face with the maximal value of reflection light quantity.When detecting the target information face, change direction at once, and drive object lens 23, make away from CD 1, then, use the focus error signal that produces to focus on the guiding action.Thus, object lens 23 do not carry out knee-action repeatedly just can enter the guiding action at once, therefore can shorten the guiding needed time of action that focuses on.In addition, owing to make object lens 23, after detecting the target information face, change direction at once, therefore under the narrow and small situation of WD, can prevent that also object lens 23 and CD 1 from clashing, and object lens 23 need not be unnecessarily near CD 1 near CD 1.

In addition, when focus point detects passing through of focus point position by testing circuit 44, by using focus error signal b and from the reflected light amount signal c of reflection light quantity testing circuit 41, remove the noise of focus error signal b, carry out reliable focus point and detect, can realize stable focusing guiding thus.

In addition, even c has noise etc. at reflected light amount signal, the positive naturalization data N that the level difference of reflected light amount signal is carried out after the positive naturalization with the maximal value of reflection light quantity is at random, and 84 pairs of information faces of information faces judging circuit are differentiated under the kaput situation, also utilizes the n slow circuit 70 output counter-rotating instructions of returning.Therefore, can focus on the guiding action reliably, and can prevent that object lens 23 from conflicting with CD 1, can realize the optical disc controller that reliability is high.

In addition, differentiate under the kaput situation in information faces, make the direction that changes object lens 23 and begin timing that the level of focus error signal b judges for channeling conduct and change back (n is an integer) from the zero crossing rotation n of initial S character waveform at CD 1, thus, even have at CD 1 under the situation of face swing composition, when the level of beginning focus error signal b is judged, also can guarantee focus necessarily than information faces 1A by the lining.Like this, can focus on the guiding action to the 1st information faces 1A reliably, and can not fail.

In addition, calculate rotation by rotating speed Vrot and wait for revolution n and lens translational speed Vlns according to CD 1, even the rotating speed Vrot difference of CD 1 also can roughly keep constant with lens translational speed Vlns, the stability in the time of therefore guaranteeing to focus on guiding.And, differentiate under the kaput situation in information faces, also object lens 23 always can be remained preset distance L from the amount of movement that initial S character waveform detects after CD 1 rotation n changes, can avoid object lens 23 unnecessarily near CD 1.

In the present embodiment, with drive signal generation circuit 42C as object lens 23 are illustrated from the circuit that drives to the direction near CD 1 at first.But the present invention is not limited to this, can consider that also the face swing etc. of CD 1 drives, and makes object lens 23 change direction afterwards, and drive only away from CD 1 preset distance L initial, makes near CD 1.

Remain the method for preset distance L as amount of movement, can be following structure also, and be not limited to present embodiment object lens 23.That is, make lens translational speed Vlns constant, and irrelevant with the rotating speed Vrot of CD 1, behind 23 mobile preset distance L of object lens, after rotating the n commentaries on classics, CD 1 is parked in this position, detecting CD 1 rotation n commentaries on classics back change direction from initial S character waveform.Similarly, also can irrespectively set rotation and wait for revolution n, and be not limited to present embodiment with rotating speed Vrot.

(embodiment 4)

Figure 10 is the block diagram of a structure example of the optical disc controller that relates to of expression embodiment of the present invention 3.In Figure 10,, give prosign and omit its explanation for the textural element identical with conventional example, embodiment 1, embodiment 2 and embodiment 3.

In Figure 10, information faces judging circuit 84A, differentiating its S character waveform according to the reflection light quantity difference after the positive naturalization of positive naturalization circuit 83 outputs is S character waveform beyond the surperficial 1C, promptly, be the S character waveform of the 1st information faces 1A or information faces 1B.Just, in the present embodiment, suppose that the information faces judging circuit 84 of the ratio of precision embodiment 3 that information faces is differentiated is poor, can not correctly distinguish the 2nd information faces 1B and the 1st information faces 1A sometimes.

Till the S character waveform of constant calculations circuit 71A beyond information faces judging circuit 84A detects surperficial 1C, the same with embodiment 3, with above-mentioned formula (1) and formula (2) computed range L, revolution n and actuating speed Vlns are waited in rotation, and during the S character waveform beyond information faces judging circuit 84A detects surperficial 1C, according to object lens 23 behind the S character waveform that detects the 2nd information faces 1B will near CD 1 apart from S, the rotating speed Vrot of coil motor 24 calculates the rotation of setting with following formula (3) and formula (4) and waits for revolution m in m described later returns slow circuit 72, the actuating speed Vlns2 of the object lens of in drive signal generation circuit 42D, setting 23.

m＝K×S×Vrot …(3)

Vlns2＝(S×Vrot)/m …(4)

At this, to guarantee to move to the 1st information faces 1A from the 2nd information faces 1B the distance that object lens 23 must move as preset distance S for the focus that makes object lens 23 at least.The pass of L and S is L〉S, when considering to make it positively mobile scheduled volume, the difference of L and S is greater than the distance from surperficial 1C to the 2 information faces 1B with comprising individual deviation.

M returns slow circuit 72 based on from the output signal of information faces judging circuit 84A with from the output signal of focus point by testing circuit 44, after changeing to CD 1 rotation m from the zero cross point of the S character waveform of the 1st information faces 1A or the 2nd information faces 1B, to counter-rotating instruction circuit 40A output signal.

The counter-rotating instruction circuit 40A timing output counter-rotating instruction f of which output signal early in the output signal of slow circuit 72 that returns in the output signal of the slow circuit 70 of returning from n with from m, and send to steering circuit 32A and drive signal generation circuit 42D.

Then, the action of the optical disc controller that constitutes like that more than illustrating with reference to Figure 11.Figure 11 is the oscillogram of each several part signal of the optical disc controller of Figure 10.

In Figure 11, focus on key instruction h and send to drive signal generation circuit 42D from system controller 30.Aberration setting apparatus 63 is adjusted aberration adjuster 65, makes the 1st specified information faces 1A is not produced spherical aberration.Drive signal generation circuit 42D output drive signal, this drive signal are to make lens translational speed Vlns that object lens 23 calculate from formula (1) and formula (2) with the constant calculations circuit 71A drive signal near the direction of CD 1.When object lens 23 during near CD 1, its focus is by surperficial 1C and the 2nd information faces 1B, and from focus error detection circuit 12 consequent S character waveform b1 of output and b2.

Maximum value/minimal value testing circuit 80 these S character waveforms of output b1, the peak of b2 and the timing of paddy, reflection light quantity difference detecting circuit 81 calculates the poor Δ V of reflection light quantity testing circuit 41 in this output valve regularly.When focus point detected passing through of S character waveform by testing circuit 44, maximum value detecting circuit 82 was determined maximal value Vmax, and sends to positive naturalization circuit 83.Positive naturalization circuit 83 usefulness Δ V and Vmax calculate positive naturalization data N (=Δ V/Vmax), align naturalization data N and predetermined value Ncmp compares by information faces judging circuit 84A, and being judged as the 2nd S character waveform b2 is not the waveform of surperficial 1C.At this moment, shown in arrow A R, if can carry out the differentiation of information faces, then the rotatable phase signal of coil motor 24 is consistent with the zero cross point of the S character waveform b2 that determines.

Constant calculations circuit 71A uses above-mentioned formula (3) and formula (4) to calculate the speed Vlns2 of wait revolution m=1 and object lens 23 according to the rotating speed Vrot of CD 1 of this moment, and sets in drive signal generation circuit 42D and m return slow circuit 72.Drive signal generation circuit 42D output drive signal makes actuating speed Vlns2 that object lens calculate with constant calculations circuit 71A near CD 1.The m slow circuit 72 of returning is a starting point with the zero cross point of the S character waveform b2 of the 2nd information faces 1B, after the time that CD 1 rotation 1 is changeed, to counter-rotating instruction circuit 40A output signal.Object lens 23 were to 1 timing near preset distance S of CD after this was equivalent to detect the 2nd S character waveform b2.

The return output signal of slow circuit 70 of the output signal ratio n of slow circuit 72 is input to counter-rotating instruction circuit 40A earlier because m returns, and the instruction circuit 40A that therefore reverses regularly exports counter-rotating instruction f1 in the return output of slow circuit 72 of m.Drive signal generation circuit 42D accepts counter-rotating instruction f1, and switches to and make the drive signal of object lens 23 away from the direction of CD 1.Simultaneously, the focusing steering circuit 32D that has accepted counter-rotating instruction f1 becomes the state that can carry out the guiding action judged based on the level of focus error signal b.

When object lens 23 move on away from the direction of CD 1, and during from focus error detection circuit 12 output S character waveform b4, focus on the level judgement that steering circuit 32D carries out focus error signal b4, the timing that reaches the guiding level at this level is to commutation circuit 31 output switching command g, the signal a that outputs to actuator driving circuit 21 is switched to the output signal of control circuit 20 from the output signal of drive signal generation circuit 42D, and focus on the guiding action by start-up control circuit 20.

On the other hand, in the present embodiment, similarly be provided with the n slow circuit 70 of returning with embodiment 1 and embodiment 2, because when information faces former thereby that can not carry out information faces judging circuit 84A such as the noise that output signal comprised of reflection light quantity testing circuit 41 is differentiated, be used to the return input signal output counter-rotating instruction f of slow circuit 70 from n.

As mentioned above, according to present embodiment, the output signal of drive signal generation circuit 42D makes object lens 23 near CD 1, it is poor at the reflection light quantity of the timing of Feng Hegu to calculate focus error signal b, by comparing value and the predetermined value that it carries out after the positive naturalization with the maximal value of reflection light quantity, information faces judging circuit 84A detects the information faces beyond the surperficial 1C, afterwards m return slow circuit 72 rotation 1 (=m) change back output signal, counter-rotating instruction circuit 40A output counter-rotating instruction f.Thus, detect the 2nd information faces 1B, make afterwards object lens 23 to 1 of CD near apart from S, even the precision of information faces judging circuit 84A is low like this, do not make object lens 23 near CD 1 yet, under the narrow and small situation of WD, can prevent that also object lens 23 and CD 1 from clashing.

In addition, focus error signal b and reflected light amount signal c one are used from focus point detect passing through of focus point positions, remove the noise of focus error signal b thus, carry out reliable focus point and detect, thereby can realize that stable focusing guides by testing circuit 44.

In addition, even c has noise etc. at reflected light amount signal, the value N that the reflection light quantity difference is carried out after the positive naturalization with the maximal value of reflection light quantity is at random, the information faces of information faces judging circuit 84 is differentiated under the kaput situation, owing to utilize the n slow circuit 70 output counter-rotating instructions of returning, therefore can focus on the guiding action reliably, and can prevent that object lens 23 from conflicting with CD 1, can realize the optical disc controller that reliability is high.

In addition, making in the direction that changes object lens 23 and beginning the timing that the level of focus error signal b judges for channeling conduct changes back (n is an integer) and changes back (m is an integer) from the zero crossing of the S character waveform beyond the surperficial 1C to CD 1 rotation m to CD 1 rotation n in the zero crossing from initial S character waveform, thus, even have at CD 1 under the situation of face swing composition, when the level of beginning focus error signal b is judged, also can guarantee focus necessarily than information faces 1A by the lining.Like this, can focus on guiding to the 1st information faces 1A reliably.

In addition, calculate rotation by rotating speed Vrot and wait for revolution n and m, lens translational speed Vlns and Vlns2 according to CD 1, even the rotating speed Vrot difference of CD 1 also can roughly keep constant with lens translational speed Vlns and Vlns2, the stability in the time of therefore guaranteeing to focus on guiding.

And, object lens 23 always can be remained preset distance L and S respectively from the amount of movement that detects after CD 1 rotation m changes that detects amount of movement after CD 1 rotation n changes and the object lens 23 S character waveform beyond the surperficial 1C of initial S character waveform, can avoid object lens 23 unnecessarily near CD 1.

In the present embodiment, with drive signal generation circuit 42C as object lens 23 are illustrated from the circuit that drives to the direction near CD 1 at first.But the present invention is not limited to this, can consider that also the face swing etc. of CD 1 drives, and makes object lens 23 change direction afterwards, and drive only away from CD 1 preset distance initial, makes near CD 1.

Remain the method for preset distance L or S as amount of movement, can be following structure also, and be not limited to present embodiment object lens 23.That is, make lens translational speed Vlns or Vlns2 constant, and irrelevant with the rotating speed Vrot of CD 1, behind 23 mobile preset distance L of object lens or S, rotated that n changes or m transfers to and is parked in this position with onlying up to CD 1, changeed or after m changes the change direction at rotation n.Similarly, also can irrespectively set rotation and wait for revolution n or m, and be not limited to present embodiment with rotating speed Vrot.

(embodiment 5)

Figure 12 is the block diagram of a structure example of the optical disc controller that relates to of expression embodiment of the present invention 5.In Figure 12,, give prosign and omit its explanation for the textural element identical with conventional example, embodiment 1, embodiment 2, embodiment 3 and embodiment 4.

S word polarity discriminating circuit 90 is under the condition of reflected light amount signal c more than or equal to predetermined value Clvl from reflection light quantity testing circuit 41, the order that occurs based on maximum value and minimal value from the focus error signal b of focus error detection circuit 12, when for example minimal value is followed maximum value and is occurred, output+1, when maximum value is followed minimal value and is occurred, output-1.Focal position judging circuit 91, when reflected light amount signal c is less than or equal to predetermined value Clvl, to carrying out additive operation from the output signal of S word polarity discriminating circuit 90, differentiate present focal position based on this operation values, and, detect focus thus and passed through the target information face, output counter-rotating instruction f.Drive signal generation circuit 42E output make object lens 23 away from or near the signal of CD 1.

Then, the action of the optical disc controller that constitutes like that more than the oscillogram explanation with reference to Figure 12 and Figure 13.

In Figure 13, CD 1 has face swing composition, and the part that has schematically showed illuminating laser beam is because of the rotation of CD 1 teetertotters, be with Figure 13 in the overlapping sine wave of output signal a of drive signal generation circuit 42E.In these sine waves, solid line, dotted line, dot-and-dash line be the face swing composition of presentation surface 1C, the 2nd information faces 1B, the 1st information faces 1A respectively.

At first, focus on key instruction h and send to drive signal generation circuit 42E from system controller 30.Drive signal generation circuit 42E output makes object lens 23 with the drive signal of predetermined speed near the direction of CD 1.When object lens 23 during near CD 1, its focus is by surperficial 1C, thus from 12 outputs of focus error detection circuit then maximum value minimizing S character waveform b1 appears, 90 outputs+1 of S word polarity discriminating circuit.At this constantly, the count value of focal position judging circuit 91 inside is+1.

And then when object lens 23 during near CD 1, its focus is by the 2nd information faces 1B, thus from 12 outputs of focus error detection circuit then maximum value minimizing S character waveform b2 appears, 90 outputs+1 of S word polarity discriminating circuit.At this constantly, the count value of focal position judging circuit 91 inside is+2.

When object lens 23 are driven it near the direction of CD 1, the distance of object lens 23 and CD 1 strengthens because of the face swing that CD 1 has, focus is successively by the 2nd information faces 1B, surface C, follow the S character waveform (b3, b4) that maximum value appears in minimal value from the 12 double outputs of focus error detection circuit thus, 90 twice output-1 of S word polarity discriminating circuit.Thereby the count value of focal position judging circuit 91 inside changes by+1,0.

When under this state when object lens 23 drive it near the direction of CD 1, because of the rocking of CD 1 that the face swing causes calmed down, focus is successively by surperficial 1C (S character waveform b5), the 2nd information faces 1B (S character waveform b6), the 1st information faces 1A (S character waveform b7), this time, S word polarity discriminating circuit 90 outputs+1.At this moment, focal position judging circuit 91, its inner count value by+1 ,+2 ,+3 change, becoming+3 timing, to focusing on steering circuit 32E and drive signal generation circuit 42E output counter-rotating instruction f.

Drive signal generation circuit 42E accepts counter-rotating instruction f, switches to and makes the drive signal of object lens 23 away from the direction of CD 1.Simultaneously, the focusing steering circuit 32E that has accepted counter-rotating instruction f becomes the state that can carry out the guiding action judged based on the level of focus error signal b.

When object lens 23 move on away from the direction of CD 1, and during from focus error detection circuit 12 output S character waveform b8, focus on the level judgement that steering circuit 32E carries out focus error signal b8, the timing that reaches the guiding level at this level is to commutation circuit 31 output switching command g, the signal a that outputs to actuator driving circuit 21 is switched to the output signal of control circuit 20 from drive signal generation circuit 42E, and focus on the guiding action by start-up control circuit 20.

As mentioned above, in the present embodiment, the output signal of drive signal generation circuit 42E makes object lens 23 near CD 1, differentiates S word polarity according to the peak of focus error signal b and the order of paddy appearance, differentiate the position of focus according to this differentiation result, detect the target information face thus.Then, when detecting the target information face, change direction at once, and drive object lens 23, make, then, use the focus error signal b that produces to focus on the guiding action away from CD 1.Like this, object lens 23 do not carry out knee-action repeatedly just can enter focusing guiding action at once, therefore can shorten the needed time of action that guides that focuses on.And, by making object lens 23, and after detecting the target information face, changing direction at once near CD 1, object lens 23 need not be unnecessarily near CD 1, can prevent that also object lens 23 and CD 1 from clashing under the narrow and small situation of WD.

S word polarity discriminating circuit 90 and focal position judging circuit 91 are in action separately, by using focus error signal b and from the reflected light amount signal c of reflection light quantity testing circuit 41, remove the noise of focus error signal b, move reliably, can realize stable focusing guiding thus.

In the present embodiment, with drive signal generation circuit 42E as make object lens 23 from initial near the direction of CD 1, its circuit that drives being illustrated.But the present invention is not limited to this, can consider that also the face swing of CD 1 drives, and makes make 23 on object lens change direction afterwards, and drive away from CD 1 preset distance at first, makes near CD 1.

As mentioned above, according to the present invention, object lens do not carry out knee-action repeatedly just can enter focusing guiding action at once, therefore can shorten the needed time of action that guides that focuses on.

And object lens need not be unnecessarily near CD, can prevent that also object lens and CD from clashing under the narrow and small situation of WD.

In addition, the CD for inside has a plurality of information faces also can detect the target information face reliably, can focus on the guiding action reliably to the target information face.

Claims (18)

1. optical disc controller comprises:

Assemble irradiation unit, the information carrier with a plurality of information faces is assembled illumination beam via object lens;

Focus on mobile device,, the focus of the light beam of being assembled by above-mentioned convergence irradiation unit is moved on the normal direction of the face of above-mentioned information carrier by moving above-mentioned object lens;

Focusing-error detecting device generates focus error signal, and this focus error signal is corresponding to the offset of the focus of each face of the above-mentioned relatively information carrier of light beam;

Focus point detects surface and each information faces that beams focusing point has passed through above-mentioned information carrier by pick-up unit;

The counter-rotating command device uses from above-mentioned focus point and exports the counter-rotating instruction by the output signal of pick-up unit;

Driving signal generator, output makes the signal of above-mentioned object lens near above-mentioned information carrier to above-mentioned focusing mobile device, and switches to according to above-mentioned counter-rotating instruction and to make the signal of above-mentioned object lens away from above-mentioned information carrier, and output;

Control device uses above-mentioned focus error signal to control above-mentioned focusing mobile device, makes focus point follow the trail of each information faces of above-mentioned information carrier; And

Focus on guiding device,, will move and switch to above-mentioned control device, focus on the guiding action by above-mentioned focusing mobile device from above-mentioned driving signal generator by switching command.

2. optical disc controller according to claim 1 is characterized in that, above-mentioned optical disc controller also comprises:

Amplitude detecting device detects the amplitude of above-mentioned focus error signal; And

The characteristic correcting device, use above-mentioned amplitude detecting device focus point by the time amplitude, the ride gain characteristic of above-mentioned control device is revised, the control action that make to focus on after the guiding is stable.

3. optical disc controller according to claim 1 is characterized in that, above-mentioned optical disc controller also comprises:

The reflection light quantity pick-up unit, detect with from the corresponding signal of the catoptrical light quantity of above-mentioned information carrier;

Above-mentioned focus point based on the output signal from above-mentioned reflection light quantity pick-up unit, detects passing through of focus point by pick-up unit.

4. optical disc controller according to claim 1 is characterized in that:

The signal that the inclination of above-mentioned driving signal generator output drive waveforms when switching the signal corresponding with above-mentioned counter-rotating instruction little by little changes.

5. optical disc controller according to claim 3 is characterized in that, above-mentioned optical disc controller also comprises:

Amplitude detecting device detects the amplitude of above-mentioned focus error signal;

The spherical aberration adjustment device carries out variable setting according to target face to the amount of spherical aberration of the focus of the light beam assembled by above-mentioned convergence irradiation unit; And

The information faces pick-up unit uses the output signal from above-mentioned amplitude detecting device, detects above-mentioned target face from a plurality of information faces of above-mentioned information carrier.

6. optical disc controller according to claim 5 is characterized in that, above-mentioned optical disc controller also comprises:

The phase relation pick-up unit, from the level of the reflected light amount signal of above-mentioned reflection light quantity pick-up unit and from the maximum value of the reflected light amount signal of above-mentioned reflection light quantity pick-up unit, detect the phase relation of above-mentioned focus error signal and above-mentioned reflected light amount signal when getting maximum value and minimal value based on above-mentioned focus error signal;

Above-mentioned information faces pick-up unit is based on the phase relation from the output of above-mentioned phase relation pick-up unit, detects above-mentioned target face from a plurality of information faces of above-mentioned information carrier.

7. optical disc controller according to claim 6 is characterized in that:

When above-mentioned phase relation pick-up unit detected the phase relation of above-mentioned focus error signal and above-mentioned reflected light amount signal, above-mentioned focus error signal is maximum value and minimizing timing detection with the level of above-mentioned reflected light amount signal was condition more than or equal to predetermined value.

8. optical disc controller according to claim 1 is characterized in that, above-mentioned optical disc controller also comprises:

Amount of movement management pick-up unit A detects by pick-up unit above-mentioned focus point and to move scheduled volume by the focus point rear focal point and manage and detect;

Above-mentioned counter-rotating command device is based on the output signal from above-mentioned amount of movement management pick-up unit A, to replace from the output signal of above-mentioned focus point by pick-up unit output counter-rotating instruction.

9. optical disc controller according to claim 8 is characterized in that, above-mentioned optical disc controller also comprises:

Rotating driving device is rotated driving with predetermined rotating speed to above-mentioned information carrier; And

Revolution management pick-up unit is benchmark with above-mentioned focus point by the position that pick-up unit has detected the above-mentioned information carrier by focus point, above-mentioned information carrier has only been rotated predetermined revolution managed and detected to the said reference position afterwards;

Above-mentioned counter-rotating command device uses from the output signal of above-mentioned amount of movement management pick-up unit A and the output signal of managing pick-up unit from above-mentioned revolution, to replace from the output signal of above-mentioned focus point by pick-up unit, exports above-mentioned counter-rotating instruction.

10. optical disc controller according to claim 8 is characterized in that, above-mentioned optical disc controller also comprises:

The information faces discriminating gear, whether differentiate above-mentioned focus point is the target face of channeling conduct by the detected face of pick-up unit;

Above-mentioned counter-rotating command device uses from the output signal of above-mentioned amount of movement management pick-up unit A with from the output signal of above-mentioned information faces discriminating gear, to replace from the output signal of above-mentioned focus point by pick-up unit, exports above-mentioned counter-rotating instruction.

11. optical disc controller according to claim 1 is characterized in that, above-mentioned optical disc controller also comprises:

The focal position pick-up unit, the focal position of each information faces in the above-mentioned relatively information carrier of detection light beam;

S word polarity discriminating device, when above-mentioned focal position pick-up unit detects the focal position of each information faces of the above-mentioned relatively information carrier of light beam, the S word signal that output is formed by the maximum value and the minimal value of above-mentioned focus error signal, and to differentiate be to be minimizing order after the maximum value, and still minimal value is the order of maximum value afterwards.

12. optical disc controller according to claim 11 is characterized in that, above-mentioned optical disc controller also comprises:

The reflection light quantity pick-up unit, detect with from the corresponding signal of the reflection light quantity of above-mentioned information carrier;

During the focal position of each information faces in above-mentioned focal position pick-up unit detects the above-mentioned relatively information carrier of light beam, the reflected light amount signal from above-mentioned reflection light quantity pick-up unit when getting maximum value and minimal value with above-mentioned focus error signal is a condition more than or equal to predetermined value.

13. optical disc controller according to claim 1 is characterized in that, above-mentioned optical disc controller also comprises:

The face discriminating gear, differentiating by above-mentioned focus point is the predetermined face that above-mentioned information carrier comprises by the detected face of pick-up unit;

The amount of movement setting device based on the output signal from above-mentioned discriminating gear, is set the amount of movement of above-mentioned object lens;

Amount of movement management pick-up unit B detects the amount of movement that only moves the object lens that set by above-mentioned amount of movement setting device by the focus point rear focal point to above-mentioned focus point by pick-up unit and manages and detect; And

Above-mentioned counter-rotating command device uses the output signal from above-mentioned amount of movement management pick-up unit B, to replace from the output signal of above-mentioned focus point by pick-up unit output counter-rotating instruction.

14. optical disc controller according to claim 13 is characterized in that, above-mentioned optical disc controller also comprises:

Rotating driving device is rotated driving with predetermined rotating speed to above-mentioned information carrier;

Revolution management pick-up unit is benchmark with above-mentioned focus point by the position that pick-up unit has detected the above-mentioned information carrier by focus point, above-mentioned information carrier has only been rotated predetermined revolution managed and detected to the said reference position afterwards;

Above-mentioned counter-rotating command device uses from the output signal of above-mentioned amount of movement management pick-up unit B and the output signal of managing pick-up unit from above-mentioned revolution, to replace from the output signal of above-mentioned focus point by pick-up unit, exports above-mentioned counter-rotating instruction.

15. optical disc controller according to claim 1 is characterized in that, above-mentioned optical disc controller also comprises:

Amount of movement is managed pick-up unit A, above-mentioned focus point is detected by the only mobile scheduled volume A of focus point rear focal point by pick-up unit manage and detect;

The face discriminating gear, differentiating by above-mentioned focus point is the predetermined face that above-mentioned information carrier comprises by the detected face of pick-up unit;

The amount of movement setting device based on the output signal from above-mentioned discriminating gear, is set the amount of movement of above-mentioned object lens; And

Amount of movement management pick-up unit B detects the amount of movement that only moves the object lens that set by above-mentioned amount of movement setting device by the focus point rear focal point to above-mentioned focus point by pick-up unit and manages and detect;

Above-mentioned counter-rotating command device according to from the generation of the output signal of above-mentioned amount of movement management pick-up unit B regularly with from the generation regularly of the output signal of above-mentioned amount of movement management pick-up unit A any one, to replace from the output signal of above-mentioned focus point output counter-rotating instruction by pick-up unit.

16. optical disc controller according to claim 15 is characterized in that, above-mentioned optical disc controller also comprises:

Rotating driving device is rotated driving with predetermined rotating speed to above-mentioned information carrier;

Revolution management pick-up unit is benchmark with above-mentioned focus point by the position that pick-up unit has detected the above-mentioned information carrier by focus point, above-mentioned information carrier has only been rotated predetermined revolution managed and detected to the said reference position afterwards;

Above-mentioned counter-rotating command device is except using the output signal or the output signal from above-mentioned amount of movement management pick-up unit B from above-mentioned amount of movement management pick-up unit A, also use output signal from above-mentioned revolution management pick-up unit, to replace, export above-mentioned counter-rotating instruction from the output signal of above-mentioned focus point by pick-up unit.

17., it is characterized in that above-mentioned optical disc controller also comprises according to claim 9,14 or 16 described optical disc controllers:

Revolution speed setting device, according to the above-mentioned predetermined revolution of the revolution speed calculating of above-mentioned information carrier, the above-mentioned predetermined revolution that set-up and calculated goes out in above-mentioned revolution management pick-up unit.

18. according to Claim 8,13 or 15 described optical disc controllers, it is characterized in that above-mentioned optical disc controller also comprises:

Speed setting device drives the speed of above-mentioned object lens, the speed that set-up and calculated goes out in above-mentioned driving signal generator according to the revolution speed calculating of above-mentioned information carrier.

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