CN1811931A - Optical disc device - Google Patents

Abstract

An optical disk device of the invention records/ regenerates information carrier which at least has two information faces and at least has a laminated layer, which comprises a beam irradiating mechanism, a beam-confining mechanism, a focusing device which leads the beam-confining mechanism to move, a light receiving mechanism which receives reflected light, a beam-confining status detecting mechanism which detects signals of the information faces which are corresponded with the beam-confining status, a focusing regulating mechanism which drives a focusing device and control to lead light beam bunching position when the information faces are existed, a spherical aberration detecting mechanism which detects spherical aberration signals which are produced on light beam bunching position which is corresponded with the information faces, a spherical aberration changeable mechanism which changes spherical aberration which is produced by the light beam on the bunching position through driving by an elastic body, a spherical aberration control mechanism which controls the spherical aberration changeable mechanism to lead spherical aberration to be close to zero, a deviation application device which applies deviation to the spherical aberration changeable mechanism and a deviation replacing mechanism which replaces the offset of the deviation application device according to the information faces.

Description

Optical disc apparatus

The application is that application number is 02805745.7, and denomination of invention is divided an application for " optical disc apparatus ".

Technical field

The present invention relates to carry out the optical disc apparatus of the record regenerating of optical information.The present invention be more particularly directed to: for convergent pencil of rays, utilize the big lens of numerical aperture also can good accuracy to correct spherical aberration, can carry out the possible optical disc apparatus of high-precision record regenerating.

Background technology

In the past, as preserving image information; Acoustic information or robot calculator have so-called regeneration special-purpose cd with the recording medium of the data of program etc.; Phase-change optical disk; All optical record mediums of magneto-optic disk or light-card sheet etc.

For such optical record medium (to call " CD " in the following text) lining writes data or playback record in optical disc data, utilize optical disc apparatus.In addition, the optical disc apparatus in this instructions singly is not an optical disc apparatus (CD-ROM drive), also comprises: can write data or from all devices of CD read-outing data in CD.That is, " optical disc apparatus " of this instructions comprises game machine; The audiovisual apparatus; Home-use electronics computing machine.In addition, also comprise the portable terminating machine (PDA) that can carry out the recording/reproducing of data to compact disk.

The structure of CD at first, is described in conjunction with Fig. 1.CD 20 shown in Figure 1 is the sides from bare headed illumination beam, has: the matrix part 21 of the transmitted light beam of being made by transparent material; The protective seam 25 of information faces 29 that the record regenerating data are used and protection CD.Matrix part 21 and protective seam 25 are same, have the antisitic defect of protection data of optical disk; Anti-pollution function.In addition, " matrix part " in this instructions and the predicate of " protective seam " all are meant the predicate of the transparent component that exists between the information faces of CD and the atmosphere, do not press material; Thickness; The implication of the strict difference of manufacture method " matrix part " and " protective seam ".Therefore, shaven head can be configured in a side of protective seam, and in this instructions, the parts that the parts that utilization " matrix part " predicate is represented and the predicate of " protective seam " are represented can be replaced mutually.

Fig. 2 is the shaft side figure that model utility amplifies the information faces 29 of expression CD 20.From the top of figure to CD 20 illumination beams.The magnetic track 28 that convex is arranged on the information faces 29 of CD 20 as shown in Figure 2.28 pairs of cd centre of magnetic track form with concentric circles or spiral fashion.Magnetic track 28 can be swung.Utilize the wobble shape or the hunting frequency of magnetic track 28, the information of recording address information etc. in advance on CD 20.

Fig. 3 represents the block diagram of CD device structure in the past.CD 20 is by disc motor 10 rotating speed rotation in accordance with regulations.3 emitted light beams of light source as semiconductor laser of light beam irradiates body function etc. are to come the information faces 29 of pack at CD 20 by the object lens 1 as the pack body function, on information faces 29 want to form on the position light beam spot.

The Design for optical system that comprises object lens 1 is to be prerequisite with the focus control working stability on the information faces 29 of CD 20, and the spherical aberration of fixing is corrected.That is, the thickness according to the matrix part 21 of CD 20 carries out the minimized optical design of spherical aberration.This is to correct because there is no need to carry out dynamic (dynamically) of spherical aberration in optical disc apparatus in the past.

Accept the reflected light of CD 20 by connecing light accepting part 4, generate photocurrent according to accepting light quantity.

Optical disc apparatus has focalizer 2 and tracking regulator 27.In order to change the pack position of light beam, focalizer 2 mobile object lens 1 on approximately perpendicular to information faces 29 positions of CD 20.Follow the tracks of the magnetic track 28 on the information faces 29 of CD 20 for the pack correct position of light beam, tracking regulator 27 is mobile object lens 1 on the radial direction of CD 20.

Above-mentioned object lens 1; Focalizer 2; Light source 3; Connecing light accepting part 4 concentrates on as on bare headed 5 the assembly.Can move shaven head 5 by the transport platform 60 as the searching mechanism function on the radial direction of CD 20, transport platform 60 is to be driven by the output signal of transport platform driving circuit 62 (drive signal).

Below, the focus adjustment of above-mentioned optical disc apparatus is described.

Light beam by the light source 3 of semiconductor laser etc. is generated utilizes the information faces 29 of object lens 1 pack at CD 20, forms light beam spot.The reflected light of the CD 20 of this light beam spot is injected by object lens 1 again and is being connect light accepting part 4.

Connect light accepting part 4 and be divided into four zones, the light quantity according to being detected in each zone generates photocurrent, and to prime amplifier 11 outputs.Prime amplifier 11 has the I/V converter, from connecing the photocurrent of light accepting part 4 inputs at prime amplifier 11, is transformed to voltage by the I/V converter.Each signal of conversion is sent to focus error signal maker 7 and trail-and-error signal generator 18.Focus error signal maker 7 utilizes prime amplifier 11 to generate: about being exported and the light beam spot of light harvesting and the rub-out signal of the vertical direction between the CD 20 by shaven head 5.

This optical system comprises the focusing error-detecting system that generally is referred to as the astigmatism method and is referred to as the trail-and-error detection system of the method for recommending.

Focus error signal maker 7 is according to input signal and utilize the astigmatism method to generate focus error signal (to call the FE signal in the following text).FE signal as the output signal of focus error signal maker 7 carries out phase compensation in focus adjustment portion 17; After the filtering operation of gain compensation etc., output to focalizer driving circuit 9.

Focalizer 2 drives object lens 1 according to the drive signal of focalizer driving circuit 9.Its result, light beam spot becomes the pack state of regulation in the information faces 29 of CD 20, can realize focus adjustment.

Below, the tracking Control of above-mentioned optical disc apparatus is described.

Trail-and-error signal generator 18 utilizes prime amplifier 11 to generate: the rub-out signal on the radial direction of the relevant CD 20 between the light beam spot that shaven head 5 export light harvesting also and the magnetic track 28.Trail-and-error signal generator 18 is according to input signal and utilize the method for recommending to generate trail-and-error signal (to call the TE signal in the following text).The output signal of carrying out trail-and-error signal generator 18 in tracking control section 19 is the phase compensation of TE signal; After the filtering operation of gain compensation etc., output to tracking regulator driving circuit 26.

The drive object lens of being exported according to tracking regulator driving circuit 26 by tracking regulator 27 1.Its result, light beam spot is followed the tracks of the magnetic track 28 of the information faces 29 of CD 20, can realize tracking Control.

Below, describe the generation of focus error signal and trail-and-error signal in detail in conjunction with Fig. 4.

As shown in Figure 4, connect light accepting part 4 and be divided into regional A; B; C; D.Each the regional A～D that connects light accepting part 4 generates photocurrent according to the light quantity that is detected in each zone respectively, and outputs to the corresponding I/V converter 6a that is installed in prime amplifier 11 inside; I/V converter 6b; I/V converter 6c; I/V converter 6d.

Utilize I/V converter 6a; I/V converter 6b; I/V converter 6c; I/V converter 6d is that each signal of voltage is sent to focus error signal maker 7 and trail-and-error signal generator 18 by current transformation.

" code track length direction " shown in Figure 4 is meant the tangential direction of the magnetic track 28 of CD 20, and " radial direction of CD " is meant the direction perpendicular to the magnetic track 28 of CD 20.Therefore, in the focus error signal maker 7, carry out output and computing I/V converter 6c output and that deduct I/V converter 6b and I/V converter 6d output sum of I/V converter 6a, can obtain the FE signal of astigmatism method.

In the trail-and-error signal generator 18, carry out output and computing I/V converter 6d output and that deduct the output sum of I/V converter 6b and I/V converter 6c of I/V converter 6a, can obtain the TE signal of astigmatism method.

Like this, in the optical disc apparatus in the past, CD is carried out the writing of information/or during from the CD sense information, carry out focus adjustment and tracking Control.

, in the optical disc apparatus in the past, the information of carrying out high density compact disc writes/or to read be difficult.Below, describe this point in detail.

For recording density and the high capacity that improves CD, propose to make the numerical aperture (NA) of object lens bigger than 0.6 recent years, and, make the wavelength ratio 650nm of light source also short.For example have: numerical aperture is 0.85; The wavelength of light source is 405nm; Matrix part thickness (protective layer thickness) is 0.1mm; Capacity is the CD of 20～25GB.This is because the lasing beam diameter (spot diameter) on the CD is directly proportional in λ/NA, from improving the viewpoint of recording density, makes λ little and to increase NA be favourable cause.Here, λ is a Wavelength of Laser.

If NA is 0.85; The wavelength of light source is 405nm, then, can accomplish that luminous point is little, still, can not ignore the aberration of light beam; Particularly because the caused spherical aberration of matrix part (or protective seam) of object lens and formation CD.

As shown in Figure 1, the information faces 29 of CD 20 is protected by matrix part 21, and the light beam of shaven head 5 outputs forms light beam spot by the thickness of matrix part 21 on information faces 29.

NA is in 0.6 the optical system among the employed DVD in the past, owing to the matrix part 21 spherical aberrations changes that take place in uneven thickness within allowed band, can ignore., at matrix part 21 1 regularly, light beam spot is proportional to the spherical aberration of 4 powers of NA, therefore, becomes at 0.85 o'clock at NA, can not ignore the change of spherical aberration.

In the DVD specification,, adopt two-layer dish (dual layer discs) with two information recording surfaces in order to strengthen the recording capacity of each Zhang Guangpan.Fig. 5 is the figure of one of expression dual layer discs structure example.As shown in Figure 5, dual layer discs has in order from a bare headed side: matrix part 21; LO layer (first information record surface) 22; Middle layer 24; The protective seam 25 of L1 (second information recording surface) 23 and the inside.Matrix part 21 and middle layer 24 are to be made by the transparent medium of resin etc.

According to rhythmo structure shown in Figure 5, have in the CD 20 of a plurality of information recording surfaces, light beam spot is necessary to move to adjacent information recording surface from present information recording surface.Such beam focusing position moves to different information recording surfaces, is called " interlayer moves " below.Below, in conjunction with Fig. 3 and Fig. 6 this interlayer moving method is described.

At first, consider that light beam focuses on the situation that moves to information recording surface far away from the information recording surface of close bare headed 5 object lens 1.When in a single day microcomputer 8 stopped focus adjustment, 9 outputs were used for the acceleration pulse of mobile object lens 1 to the focalizer driving circuit.This acceleration pulse has the waveform shown in Fig. 6 (a), is used for object lens 1 are moved to inboard (just from object lens 1 information recording surface one side far away) signal.

Then, microcomputer 8 is the FE signal and the beginning level that slows down of focus error signal maker 7 relatively, if the FE signal surpasses the beginning level that slows down, then exports deceleration pulse.Finishing acceleration pulse constantly, restart focus adjustment at last.

Then, consider that light beam focusing moves to the situation of near information recording surface from the information recording surface of the object lens 1 of difference shaven head 5.At this moment, utilize above-mentioned method to apply the acceleration pulse/deceleration pulse of waveform shown in Fig. 6 (b), can move light beam at interlayer and focus on.

Also need to improve recording density and high capacity in two-layer CD, for this reason, the numerical aperture of object lens is greater than 0.6, in addition, the wavelength of light source less than 650nm for well.

During two-layer dish, because between LO layer 22 and the L1 layer 23 middle layer 24 is arranged, to the thickness of information recording surface, the thickness of L1 layer 23 is greater than the thickness of LO layer 22 from the surface of the CD 20 of a bare headed side, and its amount equals the thickness in middle layer 24.The difference of this thickness is exactly the main cause that spherical aberration takes place.The NA of object lens is in the dvd pickup system of 0.6 specification, the size of this spherical aberration in allowed limits, there is no need to carry out aberration correction and can carry out recording of information regeneration, but, when utilizing the object lens of NA bigger (as more than 0.8), can not ignore because the caused spherical aberration that on another information recording surface, takes place of middle layer 24 thickness.

That is, the NA of object lens surpasses 0.6 and when becoming big, in the optical disc apparatus in the past be can not be on two information recording surfaces the information that write down of recorded information or regeneration.

NA can consider to be provided with spherical aberration correcting lens 15 shown in Figure 7 during greater than 0.6 (such as 0.8).Typical spherical aberration correcting lens 15 is to be made of two lens combination, utilizes a slice that moves two group lens to change the relative distance of two group lens.Utilize such spherical aberration correcting lens 15, when the enterprising line item of two-layer CD/regeneration, can carry out suitable spherical aberration to each information recording surface and correct, thus, can eliminate spherical aberration because of the middle layer.

Spherical aberration correcting lens 15 utilizes laminated spring to drive.At this moment, responsiveness is fast; Can carry out high-precision control, still,, spherical aberration occur and correct the narrow problem of possible range because the moving range of spherical aberration correcting lens 15 is narrow.Particularly in above-mentioned two-layer CD, if comprise the inhomogeneous of matrix part thickness; Object lens characteristic inhomogeneous; Spherical aberration correcting lens 15 characteristics inhomogeneous etc., the scope of then correcting is not enough, and existence can not be carried out the problem of record regenerating well.

Summary of the invention

The present invention uses for reference that the problems referred to above carry out, and its purpose is to provide: inhomogeneous even the thickness of the matrix part (or protective seam) of the spherical aberration generation main cause of CD has, can stablize the optical disc apparatus that carries out recording of information or stable regeneration.

Another object of the present invention also is to provide: even the NA of object lens ratio NA in the past big (such as more than 0.8), spherical aberration is corrected wide ranges; And realize the spherical aberration control that responsiveness is fast, and the possible optical disc apparatus of recording/reproducing of high density huge capacity compact discs thus.

Optical disc apparatus of the present invention is the device of record regenerating information carrier, and it comprises the light beam irradiates mechanism of illumination beam; Pack mechanism to above-mentioned information carrier pack light beam; In order to change above-mentioned light beam pack position, first regulator that above-mentioned pack mechanism is relatively moved on the almost vertical direction of information carrier information faces; Change the spherical aberration changeable mechanism of the spherical aberration that the light beam of institute of above-mentioned pack mechanism pack takes place on the pack position; Move second regulator of above-mentioned spherical aberration changeable mechanism; Move the 3rd regulator of above-mentioned spherical aberration changeable mechanism; Accept the catoptrical optical mechanism of accepting of above-mentioned beam carrier; According to the above-mentioned signal of accepting optical mechanism, detect the pack state detection mechanism corresponding to pack status signal of above-mentioned light beam on the information carrier information faces; According to the signal of above-mentioned pack state detection mechanism, above-mentioned first regulator of controlling and driving makes the focus adjustment mechanism of light beam pack in the position of wanting of above-mentioned information carrier information faces; According to the above-mentioned signal of accepting optical mechanism, detect the spherical aberration testing agency on the above-mentioned information carrier information faces corresponding to the signal of the light beam amount of spherical aberration that takes place on the pack position; According to above-mentioned spherical aberration testing agency's signal difference above-mentioned the 3rd regulator of controlling and driving and second regulator, make approximate 0 the spherical aberration control gear that becomes of spherical aberration; Wherein: above-mentioned the 3rd regulator is at least according to the flip-flop that is included in above-mentioned spherical aberration testing agency signal, move above-mentioned spherical aberration changeable mechanism, above-mentioned second regulator is according to the alternating component that is included in above-mentioned spherical aberration testing agency signal, moves above-mentioned spherical aberration changeable mechanism.Like this, even as big than in the past of the NA of the object lens that pack mechanism utilized (such as NA greater than 0.8; .085 more than), can realize that responsiveness is good; It is wide that spherical aberration is corrected range of control, can provide more highdensity record regenerating possible optical disc apparatus.

As desirable embodiment, above-mentioned spherical aberration control gear is the separating controlling frequency band, carry out the driving of the 3rd regulator so that be lower than the spherical aberration change of information carrier gyro frequency, and the driving of second regulator is carried out in the spherical aberration change that is higher than the information carrier gyro frequency.Its result, chase after the matrix part influence in uneven thickness that can tetchiness be subjected to each circle of configuration information carrier from slow-footed the 3rd regulator, can chase after from the variation in thickness of the matrix part of radial direction, improve spherical aberration more and corrected the precision of controlling, therefore, the responsiveness that spherical aberration is corrected becomes better, can provide the higher record regenerating of density possible optical disc apparatus.

Optical disc apparatus of the present invention is the optical disc apparatus that the information carrier that has two information faces at least of rhythmo structure is carried out record regenerating; It comprises the light beam irradiates mechanism of illumination beam; Pack mechanism to above-mentioned information carrier pack light beam; In order to change above-mentioned light beam pack position, first regulator that above-mentioned pack mechanism is relatively moved on the almost vertical direction of information carrier information faces; Change the spherical aberration changeable mechanism of the spherical aberration that the light beam of institute of above-mentioned pack mechanism pack takes place on the pack position; Move the 3rd regulator of above-mentioned spherical aberration changeable mechanism; Move second regulator of above-mentioned spherical aberration changeable mechanism; Accept the catoptrical optical mechanism of accepting of carrier of above-mentioned light beam; According to the above-mentioned optical mechanism signal of accepting, detect the pack state detection mechanism corresponding to pack status signal of above-mentioned light beam on the information carrier information faces; According to the signal of above-mentioned pack state detection mechanism, first regulator that controlling and driving is above-mentioned makes the focus adjustment mechanism of above-mentioned light beam pack in the position of wanting of above-mentioned information carrier information faces; Drive above-mentioned first regulator, make light beam pack position move to the interlayer travel mechanism of another information faces; According to the above-mentioned optical mechanism signal of accepting, detect the spherical aberration testing agency on the above-mentioned information carrier information faces corresponding to the signal of the amount of spherical aberration that takes place on the light beam pack position; According to above-mentioned spherical aberration testing agency signal, above-mentioned the 3rd regulator of controlling and driving and second regulator make approximate 0 the spherical aberration control gear that becomes of spherical aberration respectively; Wherein, above-mentioned the 3rd regulator is at least according to the flip-flop that is included in above-mentioned spherical aberration testing agency signal, moves above-mentioned spherical aberration changeable mechanism; Above-mentioned second regulator is according to the alternating component that is included in above-mentioned spherical aberration testing agency signal, move above-mentioned spherical aberration changeable mechanism, meanwhile, utilize the above-mentioned spherical aberration changeable mechanisms of driving such as the 3rd regulator, so that when the work of above-mentioned interlayer travel mechanism and the pack position of light beam move to above-mentioned another information faces, the spherical aberration minimum that produces owing to being moved.Thus, for the information carrier with at least two information faces, the spherical aberration of the wide region when interlayer moves is controlled the possibility that becomes, and can provide more highdensity record regenerating possible optical disc apparatus.

As desirable embodiment, utilize interlayer travel mechanism, when light beam pack position moved to another information faces, the signal based on the amount of spherical aberration that is taken place on above-mentioned another information faces was applied to the 3rd regulator as skew.Its result, the spherical aberration changeable mechanism moves, so that the spherical aberration along with the light beam pack position of pack mechanism during near another information faces, make that to move the spherical aberration that takes place minimum and near the spherical aberration correct amount that becomes benchmark in another owing to this, therefore, can reduce because to the influence of the mobile caused focusing mistake or the information carrier total reflection light quantity of another information faces, can not hinder the stability that moves of another information faces, thereby can provide the higher record regenerating of density possible optical disc apparatus.

As desirable embodiment, because interlayer travel mechanism, the pack position of light beam to another information faces move and till pack state detection mechanism signal pack is in given range during, do not carry out work according to the spherical aberration control gear of spherical aberration testing agency signal.Its result, when spherical aberration changeable mechanism interlayer moves, can control the change of spherical aberration testing agency signal, therefore, can realize stable control transformation, can provide the higher record regenerating of density possible optical disc apparatus each information faces spherical aberration.

Optical disc apparatus of the present invention is the device of record regenerating information carrier, and it comprises shaven head; In this shaven head with the light beam irradiates mechanism of illumination beam, pack mechanism to above-mentioned information carrier pack light beam, in order to change the pack position of above-mentioned light beam, first regulator that above-mentioned pack mechanism is relatively moved on the almost vertical direction of information carrier information faces, change on the light beam pack position of institute of above-mentioned pack mechanism pack the spherical aberration changeable mechanism of spherical aberration takes place, move the 3rd regulator of above-mentioned spherical aberration changeable mechanism, move second regulator of above-mentioned spherical aberration changeable mechanism, and accept the catoptrical mechanism of above-mentioned beam carrier as holding integratedly; According to the above-mentioned optical mechanism signal of accepting, detect the pack state detection mechanism corresponding to pack status signal of above-mentioned light beam on the information carrier information faces; According to the signal of above-mentioned pack state detection mechanism, above-mentioned first regulator of controlling and driving makes the focus adjustment mechanism of light beam pack in the position of wanting of above-mentioned information carrier information faces; According to the above-mentioned optical mechanism signal of accepting, detect the spherical aberration testing agency on the above-mentioned information carrier information faces corresponding to the amount of spherical aberration signal that takes place on the light beam pack position; According to above-mentioned spherical aberration testing agency signal, above-mentioned the 3rd regulator and second regulator of controlling and driving makes approximate 0 the spherical aberration control gear that becomes of spherical aberration respectively; The searching mechanism that above-mentioned shaven head is moved to the radial direction of above-mentioned information carrier; Wherein, above-mentioned the 3rd regulator is at least according to the flip-flop that is included in above-mentioned spherical aberration testing agency signal, moves above-mentioned spherical aberration changeable mechanism; And above-mentioned second regulator is according to the alternating component that is included in above-mentioned spherical aberration testing agency signal, moves above-mentioned spherical aberration changeable mechanism; Meanwhile, drive above-mentioned the 3rd regulator, the spherical aberration minimum that takes place so that light beam pack position when moving to the different radii position of above-mentioned information carrier by above-mentioned pack mechanism, makes above-mentioned moving.Like this, utilize the 3rd regulator to correct, the flip-flop signal of the spherical aberration testing agency that shaven head is taken place when radial direction moves by above-mentioned searching mechanism; Thus, absorb the inhomogeneous of information carrier thickness or paste uneven; Can carry out the spherical aberration of wide ranges and correct control, thereby, can provide the higher record regenerating of density possible optical disc apparatus.

As desirable embodiment, because above-mentioned searching mechanism work, light beam pack position is in the moving of the radial location of another information faces, and the signal according to the amount of spherical aberration that is taken place on above-mentioned another information faces radial location is applied to the 3rd regulator as skew.Its result, the spherical aberration changeable mechanism make shaven head from interior circumferential periphery near the time because this moves the spherical aberration minimum that is taken place; Promptly, more near the spherical aberration correct amount as benchmark of target circumferential position, therefore, can reduce by the caused influence of the spherical aberration cataclysm of shaven head in radial direction moves trail-and-error signal or focus error signal, can not hinder the stability of the work that retracts of the tracking Control after radial direction moves, can provide the higher record regenerating of density possible optical disc apparatus.

In desirable embodiment, by searching mechanism work, move to another information faces light beam pack position, and on another information faces radial location, the signal pack of pack state detection mechanism is not carried out work according to the spherical aberration control gear of spherical aberration testing agency signal during before the afore mentioned rules scope.Its result by searching mechanism, can realize the more stable spherical aberration control transformation when radial direction moves, and can provide the higher record regenerating of density possible optical disc apparatus.

Optical disc apparatus of the present invention is the optical disc apparatus that the information carrier that has two information faces at least of rhythmo structure is carried out record regenerating, and it comprises: the light beam irradiates mechanism of illumination beam; Pack mechanism to above-mentioned information carrier pack light beam; In order to change above-mentioned light beam pack position, the focalizer that above-mentioned pack mechanism is relatively moved on the almost vertical direction of information carrier information faces; Accept the catoptrical optical mechanism of accepting of carrier of above-mentioned light beam; According to the above-mentioned optical mechanism signal of accepting, detect the pack state detection mechanism corresponding to pack status signal of above-mentioned light beam on the information carrier information faces; According to the signal of above-mentioned pack state detection mechanism, the above-mentioned focalizer of controlling and driving makes the light beam pack want the focus adjustment mechanism of position in above-mentioned information carrier information faces; According to the above-mentioned optical mechanism signal of accepting, detect the spherical aberration testing agency on the above-mentioned information carrier information faces corresponding to the signal of the amount of spherical aberration that is taken place on the light beam pack position; Utilize to drive elastomeric method, change the spherical aberration changeable mechanism of the spherical aberration that the light beam of institute of above-mentioned pack mechanism pack takes place on the pack position; According to above-mentioned spherical aberration testing agency signal, the above-mentioned spherical aberration changeable mechanism of controlling and driving makes approximate 0 the spherical aberration control gear that becomes of spherical aberration; On above-mentioned spherical aberration changeable mechanism, apply the skew applying mechanism of skew; Replace the skew of the side-play amount of above-mentioned skew applying mechanism corresponding to the information faces of above-mentioned information carrier and replace mechanism.Like this, can stablize and high-precision spherical aberration rectification control, can provide the higher record regenerating of density possible optical disc apparatus.

As desirable embodiment, when above-mentioned spherical aberration control gear is not worked, given skew is applied to the spherical aberration changeable mechanism by the skew applying mechanism; When the spherical aberration control gear is worked, decide skew according to the average driving output of the above-mentioned spherical aberration changeable mechanism in each week of information carrier, and replace the skew that is applied to offsetting mechanism.Its result more can improve chasing after from speed that spherical aberration changes, can provide the higher record regenerating of density possible optical disc apparatus.Optical disc apparatus of the present invention is the optical disc apparatus of record regenerating information carrier, and it comprises: the light beam irradiates mechanism of illumination beam; Pack mechanism to above-mentioned information carrier pack light beam; In order to change above-mentioned light beam pack position, the focalizer that above-mentioned pack mechanism is relatively moved on the almost vertical direction of information carrier information faces; Change the spherical aberration changeable mechanism of the spherical aberration that the light beam of institute of above-mentioned pack mechanism pack takes place on the pack position; Acceptance is from the optical mechanism of accepting of the formation carrier reflects light of above-mentioned light beam; According to the above-mentioned optical mechanism signal of accepting, detect the pack state detection mechanism corresponding to pack status signal of above-mentioned light beam on the information carrier information faces; According to the signal of above-mentioned pack state detection mechanism, the above-mentioned focalizer of controlling and driving makes the focus adjustment mechanism of above-mentioned light beam pack in the position of wanting of above-mentioned information carrier information faces; According to the above-mentioned optical mechanism signal of accepting, detect the spherical aberration testing agency on the above-mentioned information carrier information faces corresponding to the signal of the amount of spherical aberration that takes place on the light beam pack position; According to above-mentioned spherical aberration testing agency signal, control moving sphere aberration changeable mechanism makes approximate 0 the spherical aberration control gear that becomes of spherical aberration; The signal value of above-mentioned spherical aberration control gear is in specialized range the time, and the dead zone that makes signal from above-mentioned spherical aberration control gear not be delivered to above-mentioned spherical aberration changeable mechanism generates mechanism.Like this, can reduce: excessively sensitivity (replying) is caused because of the spherical aberration changeable mechanism, the signal of spherical aberration testing agency changes the excessive displacement error when small, especially because of the variation in thickness of CD when the spiral parity checking work medium and low frequency breaking pitch surface aberration, can carry out slick and sly chasing after, can provide the higher record regenerating of density possible optical disc apparatus from control.

Optical disc apparatus of the present invention is the optical disc apparatus of record regenerating information carrier, and it comprises: the light beam to information carrier pack light beam occupies bundle mechanism; Make above-mentioned pack mechanism for the focalizer that moves on the approximately perpendicular direction of information carrier information faces; Change the spherical aberration changeable mechanism of the spherical aberration that institute of above-mentioned pack mechanism pack light beam takes place on the pack position; Make above-mentioned spherical aberration changeable mechanism carry out the driving mechanism of work; Acceptance is from the catoptrical optical mechanism of accepting of the information carrier of above-mentioned light beam; According to the above-mentioned optical mechanism signal of accepting, detect the pack state detection mechanism corresponding to pack status signal of above-mentioned light beam on the information carrier information faces; According to the signal of above-mentioned pack state detection mechanism, the above-mentioned focalizer of controlling and driving makes the focus adjustment mechanism of light beam pack in the position of wanting of above-mentioned information carrier information faces; According to the above-mentioned optical mechanism signal of accepting, detect the spherical aberration testing agency on the above-mentioned information carrier information faces corresponding to the amount of spherical aberration signal that takes place on the light beam pack position; According to above-mentioned spherical aberration testing agency signal, the above-mentioned driving mechanism of controlling and driving makes approximate 0 the spherical aberration control gear that becomes of spherical aberration; Gain is in accordance with regulations amplified after the above-mentioned pack status signal, and the method that is added in the detection signal of above-mentioned spherical aberration testing agency is corrected the interference that above-mentioned spherical aberration control gear and focus adjustment mechanism take place in working order or the spherical aberration straightening mechanism of interference.Like this, even the NA of the object lens that utilize as pack mechanism is than in the past bigger (is 0.8 or more or more than 0.85 such as NA), the responsiveness height can realize that the spherical aberration of wide ranges is controlled, and can provide the higher record regenerating of density possible optical disc apparatus.

Embodiment as desirable also comprises: add the first test signal generating mechanism of testing signal on above-mentioned focalizer; Detect the first amplitude detecting mechanism of the detection signal amplitude of spherical aberration testing agency, and spherical aberration is corrected learning organization, it is the state that test signal is added in above-mentioned focalizer by the above-mentioned first test signal generating mechanism that this spherical aberration is corrected learning organization, the additive operation of being obtained the spherical aberration signal straightening mechanism by the above-mentioned first amplitude detecting mechanism gains, so that the spherical aberration of above-mentioned spherical aberration detection signal amplitude minimum is corrected learning organization.Its result can provide the optical disc apparatus to each record regenerating; Especially can carry out the optical disc apparatus that spherical aberration control interference was regulated and can be got rid of in optimum focusing to each CD.

As desirable embodiment, it is in the work of focus adjustment mechanism and above-mentioned spherical aberration control gear when not working that above-mentioned spherical aberration is corrected learning organization, carries out the computing of additive operation gain.Its result can provide: because the interference of focus adjustment and spherical aberration control before two control system job insecurities, can be got rid of the optical disc apparatus of interference.

As desirable embodiment, above-mentioned spherical aberration signal straightening mechanism comprises: mechanism is preserved in additive operation gain, is used to have the mechanism of the other additive operation gain of each layer of the information carrier of rhythmo structure information faces with preservation; Mechanism is replaced in the additive operation gain, so that the additive operation gain corresponding to light beam is added in the mechanism that mechanism is preserved in above-mentioned additive operation gain.Its result when carrying out different information faces mobile, there is no need to relearn each time the focus adjustment and the spherical aberration ELIMINATION OF ITS INTERFERENCE amount that are adapted to information faces, thereby provides the optical disc apparatus that carries out record regenerating at a high speed to become possibility.

Embodiment as desirable also comprises: the first test signal generating mechanism that test signal is added in above-mentioned focalizer; Adjust the focus adjustment gain adjusting mechanism of focus adjustment mechanism gain; Test signal is added in the second test signal generating mechanism of driving mechanism; Adjust the spherical aberration ride gain adjusting mechanism of spherical aberration control gear gain; Wherein, after focus adjustment mechanism and the work of spherical aberration control gear, above-mentioned first test signal after first test signal that is taken place according to the above-mentioned first test signal generating mechanism and focus adjustment one are touring, above-mentioned focus adjustment gain adjusting mechanism is adjusted; Above-mentioned spherical aberration test signal after the spherical aberration test signal that is taken place according to the above-mentioned second test signal generating mechanism and spherical aberration control one are touring, above-mentioned adjustment spherical aberration control gear is adjusted.Its result, the disturbing effect of focus adjustment and spherical aberration control and the gain that is offset is partly included, providing of the optical disc apparatus of adjusting becomes possibility.

Optical disc apparatus of the present invention comprises: to the pack mechanism of information carrier pack light beam; The focalizer that above-mentioned pack mechanism is relatively moved on the almost vertical direction of information carrier information faces; Change the spherical aberration changeable mechanism that spherical aberration takes place institute of above-mentioned pack mechanism pack light beam on the pack position; Make the driving mechanism of above-mentioned spherical aberration changeable mechanism work; Accept above-mentioned light beam formation carrier reflects light accept optical mechanism; According to the above-mentioned optical mechanism signal of accepting, detect the pack state detection mechanism corresponding to pack status signal of above-mentioned light beam on the information carrier information faces; According to the signal of above-mentioned pack state detection mechanism, the above-mentioned focalizer of controlling and driving makes the focus adjustment mechanism of above-mentioned light beam pack in the position of wanting of above-mentioned information carrier information faces; According to the above-mentioned optical mechanism signal of accepting, detect the spherical aberration testing agency on the above-mentioned information carrier information faces corresponding to the amount of spherical aberration signal that takes place on the light beam pack position; According to above-mentioned spherical aberration testing agency signal, the above-mentioned driving mechanism of controlling and driving makes approximate 0 the spherical aberration control gear that becomes of spherical aberration; Amplify after the above-mentioned spherical aberration testing agency signal by given gain, be added in the method for the detection signal of above-mentioned pack state detection mechanism, correct the external disturbance of generation in the work of above-mentioned spherical aberration control gear of pack and focus adjustment mechanism or the pack state detection signal straightening mechanism of interference.Like this, even utilization can realize also that as NA ratio big (NA is more than 0.8 or more than 0.85) in the past of the object lens of pack mechanism responsiveness is good; The spherical aberration control of wide ranges can provide the higher record regenerating of density possible optical disc apparatus.

As desirable embodiment, comprise focus adjustment mechanism; This mechanism is when above-mentioned spherical aberration control gear is not worked, detection signal by the above-mentioned spherical aberration testing agency of pack state detection signal straightening mechanism defined multiple is not added on the detection signal of pack state detection mechanism, and only according to the detection signal of above-mentioned pack state detection mechanism, drive above-mentioned focalizer, control makes the focus adjustment mechanism of light beam pack in the position of wanting of above-mentioned information carrier information faces.Its result can provide: when the spherical aberration control gear is not worked, can prevent the unsettled optical disc apparatus of focus adjustment by the detection signal of spherical aberration testing agency.

Embodiment as desirable comprises: test signal is added in the second test signal generating means on the above-mentioned driving mechanism; Detect the second amplitude detecting mechanism of the detection signal amplitude of pack state detection mechanism; And the pack state-detection is corrected learning organization, this mechanism is added with the test signal state by the above-mentioned second test signal generating mechanism on above-mentioned driving mechanism, obtain the additive operation gain of pack state detection signal straightening mechanism, so that the virtual value minimum of the detected pack state detection signal of the above-mentioned second amplitude detecting mechanism.Its result can provide: each optical disc apparatus that carries out record regenerating can accomplish that each CD is carried out optimum focusing to be regulated and the optical disc apparatus that can get rid of spherical aberration control interference.

As desirable embodiment, above-mentioned pack state-detection is corrected learning organization to be in the work of focus adjustment mechanism and during above-mentioned spherical aberration control gear off position, to carry out the study of additive operation gain.Its result can provide: before two control system instabilities, can get rid of the optical disc apparatus of interference in the interference of focus adjustment and spherical aberration control.

Embodiment as desirable comprises: the first test signal generating mechanism that test signal is added in above-mentioned focalizer; Adjust the focus adjustment gain adjusting mechanism of focus adjustment mechanism gain; Test signal is added in the second test signal generating mechanism of above-mentioned driving mechanism; Adjust the spherical aberration ride gain adjusting mechanism of spherical aberration control gear gain; Wherein make after focus adjustment mechanism and the work of spherical aberration control gear, above-mentioned first test signal after first test signal that above-mentioned focus adjustment gain adjusting mechanism is taken place according to the above-mentioned first test signal generating mechanism and the focus adjustment-touring is adjusted; And above-mentioned spherical aberration ride gain adjusting mechanism is the above-mentioned spherical aberration test signal after controlling-go the rounds according to test signal and spherical aberration that the above-mentioned second test signal generating mechanism is taken place, adjusts.Its result can provide the more possible optical disc apparatus of high precision adjustment.

Optical disc apparatus of the present invention comprises: to the pack mechanism of information carrier pack light beam; The focalizer that above-mentioned pack mechanism is relatively moved on the almost vertical direction of information carrier information faces; Change the spherical aberration changeable mechanism that spherical aberration takes place institute of above-mentioned pack mechanism pack light beam on the pack position; Make the driving mechanism of above-mentioned spherical aberration changeable mechanism work; Accept the optical mechanism of accepting of above-mentioned light beam formation carrier reflects light; According to the above-mentioned optical mechanism signal of accepting, detect the pack state detection mechanism corresponding to pack status signal of above-mentioned light beam on the information carrier information faces; According to the signal of above-mentioned pack state detection mechanism, drive above-mentioned focalizer, control makes the focus adjustment mechanism of above-mentioned light beam pack in the position of wanting of above-mentioned information carrier information faces; According to the above-mentioned optical mechanism signal of accepting, detect the spherical aberration testing agency on the above-mentioned information carrier information faces corresponding to the respective signal of the amount of spherical aberration that takes place on the light beam pack position; From the output signal of above-mentioned spherical aberration testing agency, take out the low-pass filter mechanism that is lower than predetermined frequency component; According to the signal of above-mentioned low-pass filter mechanism, the above-mentioned driving mechanism of controlling and driving makes approximate 0 the spherical aberration control gear that becomes of spherical aberration; From the output signal of above-mentioned spherical aberration testing agency, take out the Hi-pass filter mechanism that is higher than predetermined frequency component; The signal of above-mentioned Hi-pass filter mechanism is added in the spherical aberration signal additive operation mechanism of the signal of above-mentioned pack state detection mechanism.Like this, can provide: utilize focus adjustment mechanism, can improve on light beam pack position, take place because the reduction of the RF signal reading performance of the information carrier of spherical aberration AC change.

Optical disc apparatus of the present invention comprises: to the pack mechanism of information carrier pack light beam; The focalizer that above-mentioned pack mechanism is relatively moved on the almost vertical direction of information carrier information faces; The spherical aberration changeable mechanism of spherical aberration takes place in the light beam that changes institute of above-mentioned pack mechanism pack on the pack position; Make the driving mechanism of above-mentioned spherical aberration changeable mechanism work; Acceptance is from the catoptrical optical mechanism of accepting of above-mentioned beam carrier; According to the above-mentioned optical mechanism signal of accepting, detect the pack state detection mechanism corresponding to pack status signal of above-mentioned light beam on the information carrier information faces; According to the signal of above-mentioned pack state detection mechanism, drive above-mentioned focalizer, empty system makes the focus adjustment mechanism of above-mentioned light beam pack in the position of wanting of above-mentioned information carrier information faces; According to the above-mentioned optical mechanism signal of accepting, detect the spherical aberration testing agency that takes place on the light beam pack position on the above-mentioned information carrier information faces corresponding to the signal of amount of spherical aberration; According to the detection signal of above-mentioned spherical aberration testing agency, the above-mentioned driving mechanism of controlling and driving makes approximate 0 the spherical aberration control gear that becomes of spherical aberration; The frequency band of above-mentioned focus adjustment mechanism is greater than more than ten times of above-mentioned spherical aberration control gear frequency band.Like this, the interference of focus adjustment and spherical aberration control can be left the control frequency band, and the optical disc apparatus of focus adjustment and spherical aberration control stabilization can be provided.

Optical disc apparatus of the present invention comprises: the pack mechanism of light beam pack at the information carrier with spiral fashion or concentric circles magnetic track; The focalizer that above-mentioned pack mechanism is relatively moved on the almost vertical direction of information carrier information faces; Change the spherical aberration changeable mechanism that spherical aberration takes place institute of above-mentioned pack mechanism pack light beam on the pack position; Make the driving mechanism of above-mentioned spherical aberration changeable mechanism work; The tracking regulator that above-mentioned residence bundle optical mechanism is moved on across the direction of magnetic track; Acceptance is from the catoptrical optical mechanism of accepting of above-mentioned beam carrier; According to the above-mentioned optical mechanism signal of accepting, detect the pack state detection mechanism corresponding to pack status signal of above-mentioned light beam on the information faces of information carrier; According to the signal of above-mentioned pack state detection mechanism, drive above-mentioned focalizer, control makes the focus adjustment mechanism of above-mentioned light beam pack in the position of wanting of above-mentioned information carrier information faces; According to the above-mentioned optical mechanism signal of accepting, detect the spherical aberration testing agency that takes place on the light beam pack position on the above-mentioned information carrier information faces corresponding to the signal of amount of spherical aberration; According to the detection signal of above-mentioned spherical aberration testing agency, the above-mentioned driving mechanism of controlling and driving makes approximate 0 the spherical aberration control gear that becomes of spherical aberration; According to the above-mentioned signal of accepting optical mechanism, detect the magnetic track deviation testing agency of above-mentioned light beam with respect to the respective signal of the position deviation of information carrier magnetic track; According to the signal of above-mentioned magnetic track deviation testing agency, control above-mentioned tracking regulator, control makes the tracking Control mechanism of above-mentioned beam flying at magnetic track; Make above-mentioned tracking regulator move possible conveying mechanism along the information carrier radial direction; Drive the transport driving of above-mentioned conveying mechanism; Wherein make the work of above-mentioned focus adjustment mechanism and make under the above-mentioned tracking Control mechanism off position, when making the work of above-mentioned travel mechanism, move the position that above-mentioned spherical aberration changeable mechanism is displaced to ormal weight.Like this, can provide: during the retrieval of moving along with radial direction, can reduce the bottom of trench that takes place on the FE signal across influence, can carry out the optical disc apparatus of stable focus adjustment.

Description of drawings

Fig. 1 is the mode chart of CD.

Fig. 2 is the amplification mode figure of optical disc information face.

Fig. 3 represents the block diagram of CD device structure in the past.

Fig. 4 is the block diagram that connects light accepting part and prime amplifier structure of optical disc apparatus in the past.

Fig. 5 is the CD mode chart with a plurality of information faces.

Fig. 6 (a) and (b) be the interlayer of the optical disc apparatus in the past focus drive signal oscillogram when moving.

Fig. 7 is the sectional drawing of spherical aberration correcting lens.

Fig. 8 is the block diagram of the expression embodiment of the invention 1 CD device structure.

Fig. 9 is for the light beam sectional drawing of spherical aberration detection method is described.

Figure 10 is the sectional drawing that expression in detail connects the light accepting part structure.

Figure 11 is the block diagram that expression in detail connects light accepting part and prime amplifier part.

Figure 12 (a) to (c) is that expression embodiment 1 spherical aberration is corrected drive signal waveform figure.

Figure 13 is expression embodiments of the invention 2 CD device structure block diagrams.

Figure 14 (a) to (d) is that the spherical aberration of the interlayer of expression embodiment 2 optical disc apparatus when moving corrected drive signal waveform figure.

Figure 15 is that the spherical aberration of the interlayer of embodiment 2 when moving corrected sequential flowchart.

Figure 16 is condenser lens and the LO of the interlayer of embodiment 2 when moving; The oscillogram of L1 information faces position and each signal.

Figure 17 is the block diagram of the expression embodiment of the invention 3 CD device structure.

Figure 18 (a) to (d) is that the expression spherical aberration during the radial direction of embodiment 3 moves is corrected the figure of drive signal waveform.

Figure 19 is the process flow diagram of the expression spherical aberration rectification order of expression embodiment 3 radial directions when moving.

Figure 20 is the condenser lens of embodiment 3 radial directions when moving; Dish matrix part pressure changes the oscillogram with each signal.

Figure 21 is the block diagram of the CD device structure of the expression embodiment of the invention 4.

Figure 22 (a) to (d) is that the expression spherical aberration of expression embodiment 4 optical disc apparatus interlayers when moving corrected the figure of drive signal waveform.

Figure 23 is the process flow diagram of the expression spherical aberration rectification order of expression embodiment 4 radial directions when moving.

Figure 24 is the block diagram of the expression embodiment of the invention 5 CD device structure.

Figure 25 (a) to (d) is that the spherical aberration of expression embodiment 5 optical disc apparatus interlayers when moving corrected the figure of drive signal waveform.

Figure 26 is the block diagram of the expression embodiment of the invention 6 CD device structure.

Figure 27 (a) and (b) be for the light beam sectional drawing of spherical aberration detection method is described.

Figure 28 (a) and (e) be for the oscillogram of embodiment 6 spherical aberration antidotes is described.

Figure 29 is in order to illustrate embodiment 6 spherical aberration rectification portion magnification learning methods, the block diagram of expression CD device structure.

Figure 30 (a) to (g) is the oscillogram for the study that embodiment 6 spherical aberration rectification portions are described.

Figure 31 is the process flow diagram of the spherical aberration signal rectification portion learning sequence of embodiment 6.

Figure 32 (a) to (f) is that embodiment 6 interlayers are represented the oscillogram that the magnification of spherical aberration signal rectification portion is replaced when moving.

Figure 33 is the block diagram of the expression embodiment of the invention 7 CD device structure.

Figure 34 (a) and (g) be the oscillogram of correcting for the FE signal that embodiment 7 is described.

Figure 35 is the block diagram of the FE signal rectification portion 30 of expression embodiment 7.

Figure 36 (a) to (g) is the oscillogram for the learning method of the FE signal rectification portion that embodiment 7 is described.

Figure 37 is the process flow diagram of expression learning sequence of the FE signal rectification portion of embodiment 7.

Figure 38 is the block diagram of the expression embodiment of the invention 8 CD device structure.

Figure 39 is in order to illustrate spherical aberration and to focus on the eccentric performance plot of beating.

Figure 40 (a) to (d) is in order to illustrate: embodiment 8 utilizes the method that defocuses residual spherical aberration influence, the oscillogram of correcting.

Figure 41 is the block diagram of the expression embodiment of the invention 9 CD device structure.

Figure 42 A to D is for the control frequency band that embodiment 9 is described and the performance plot of disturbing effect.

Figure 43 is for the control frequency band that embodiment 9 is described and the block diagram of disturbing effect.

Figure 44 A to D is for the control part of embodiment 9 is described; The performance plot of driving circuit and controller properties.

Figure 45 is the block diagram of the CD device structure of the expression embodiment of the invention 10.

Figure 46 (a) to (e) is the oscillogram that the spherical aberration when embodiment 10 retrieval is described is corrected.

Figure 47 is the process flow diagram of the spherical aberration rectification order of radial direction when moving of expression embodiment 10.

Figure 48 (a) to (c) be the expression embodiment 10 focus error signal in bottom of trench across the influence oscillogram.

Figure 49 (a) to (e) is the oscillogram that expression defocuses the influence that gives the spherical aberration detection signal.

Figure 50 (a) to (e) is the oscillogram that expression defocuses the influence that gives the spherical aberration detection signal.

Figure 51 (a) to (e) is the oscillogram that the difference of expression information faces gives the influence of spherical aberration detection signal.

Figure 52 (a) to (e) is the oscillogram that the difference of expression information faces gives the influence of spherical aberration detection signal.

Figure 53 (a) to (c) is that expression spherical aberration correcting lens position is to the mode chart of object lens to the influence of focusing distance.

Figure 54 (a) to (c) is that expression spherical aberration correcting lens position is to the mode chart of object lens to the influence of focusing distance.

Embodiment

Below, embodiments of the invention are described.

" embodiment 1 "

Fig. 8 is the block diagram of the expression embodiment of the invention 1 CD device structure.Fig. 9 is the sectional drawing for light beam that the spherical aberration detection method is described among Fig. 8 embodiment.Figure 10 is in the optical disc apparatus shown in Figure 8, especially describes the sectional drawing that connects light accepting part 37 parts in detail.Figure 11 is the block diagram that the detailed expression in the optical disc apparatus shown in Figure 8 connects light accepting part 37 and prime amplifier 12 parts.Inscape corresponding to optical disc apparatus in the past among these figure is attached with identical reference marks.

The focus adjustment of focus adjustment in the present embodiment and the optical disc apparatus of Fig. 3 is same, carries out to the method that the focalizer 2 as first regulator drives object lens 1.

But it is the regulator (first and second regulators) 34 that utilizes two kinds that the spherical aberration of present embodiment is corrected; 35 drive as the spherical aberration correcting lens 15 of the function of spherical aberration changeable mechanism and carry out.Below, describe this point in detail.

In the present embodiment, have spherical aberration correcting lens 15 shown in Figure 7, and have one the spherical aberration rectification regulator (second regulator) 34 of two compound lenss that are used for fine this spherical aberration correcting lens 15 of mobile formation and the stepping motor 35 (the 3rd regulator) of thick moving sphere aberration correcting lens 15 and spherical aberration rectification regulator 34.

Correcting regulator 34 as the spherical aberration of second regulator function is in order to drive as the spherical aberration correcting lens 15 of spherical aberration changeable mechanism function.This spherical aberration is corrected regulator 34 and is changed spherical aberration correcting lens 15 method at interval, can carry out the spherical aberration adjustment.It is littler than the stepping motor 35 of the following conduct that will illustrate the 3rd regulator function that spherical aberration is corrected one the scope (mobile potential range) that regulator 34 can moving sphere aberration correcting lens 15., spherical aberration is corrected regulator 34 and is responded the signal that is included in spherical aberration correcting signal alternating component (AC composition) that the spherical aberration detection signal is calculated accurately, and moving sphere aberration correcting lens 15 can carry out the rectification of spherical aberration.

Correct regulator 34 as side's lens and spherical aberration that the stepping motor 35 of the 3rd regulator can moving sphere aberration correcting lens 15.The following of 35 pairs of high-frequency signals of stepping motor is low, but that scope (mobile potential range) that can moving sphere aberration correcting lens 15 is corrected regulator 34 than spherical aberration is big.Therefore, stepping motor 35 can chase after sleekly from DC signal or low frequency signal.

In the present embodiment, the signal that is included in the flip-flop (DC composition) in the spherical aberration correcting signal of calculating according to the signal (spherical aberration detection signal) of spherical aberration detector 31, stepping motor 35 moving sphere aberration correcting lenses 15 carry out the thick rectification of spherical aberration.In addition, the rectification of the precision of spherical aberration is to correct regulator 34 by the spherical aberration of second regulator to carry out.

Spherical aberration corrects regulator 34 and stepping motor 35 is slightly driven with circuit 32 drivings by accurate the driving with circuit 33 and optical beam expander of optical beam expander respectively.Optical beam expander is accurate to be driven with circuit 33 and optical beam expander and slightly drives AC composition and the DC composition that amplifies the control signal (spherical aberration correcting signal) that microcomputer 8 exported with circuit 32 respectively.According to the spherical aberration detection signal, by microcomputer 8 output spherical aberration correcting signals.

The spherical aberration that describes embodiment 1 in conjunction with Fig. 8 to Figure 12 in detail is corrected control.Figure 12 is the oscillogram that the spherical aberration of present embodiment 1 is corrected drive signal.

At first, with reference to Fig. 8.

According to as the signal that connects light accepting part 37 of accepting optical mechanism, the focus error signal maker 36 of pack state detection mechanism function detects the signal corresponding to pack state of light beam on CD 20 information faces.Particularly, according to the signal of prime amplifier 12 output, generate from shaven head 5 outputs by the vertical direction rub-out signal between the light beam spot of light harvesting and the CD 20.

Secondly, describe the generation method of focus error signal (to call the FE signal in the following text) in detail.As shown in figure 10, connect light accepting part 37 and utilize polarization beam splitter 47 to cut apart the light beam that detects scioptics 46, on the one hand, utilize first shadow shield 48 only to take out the periphery light beam.On the other hand, utilize second shadow shield 49 only to take out interior all light beams; Utilization outer Monday of side joint light accepting part 40 respectively; Interior Monday, the side joint light accepting part 41 detected light quantity.

As shown in figure 11, outer Monday side joint light accepting part 40 and interior Monday the side joint light accepting part 41 be divided into four regional A respectively; B; C; D.Each zone generates corresponding to the photocurrent that detects light quantity, outputs to the I/V converter 42a～42d that is installed in prime amplifier 12 inside; I/V converter 43a～43d.

By I/V converter 42a～42d; The signal that I/V converter 43a～43d changes voltage into is respectively by outer Monday of side focus error signal maker 44; Interior Monday, side focus error signal maker 45 utilized and computing that focus error signal maker in the past 7 is same, changed outer Monday of side focus error signal respectively into; Interior Monday the side focus error signal.

The actual focus error signal that is used in the embodiment 1 of focus adjustment be by focus error signal maker 36 additive operations outer Monday of side focus error signal and interior Monday the side focus error signal signal.

Like this, the generation method of the focus error signal of present embodiment is somewhat different than the focus error signal of in the past astigmatism method, and still, its characteristic is of equal value.Therefore, utilize this to drive equally, realize focus adjustment, so that light beam spot pack on CD 20 information recording surfaces becomes the pack state of regulation as the FE signal of focus error signal maker 36 output signals and device in the past.

Below, in conjunction with Fig. 9; Figure 11; Figure 12 illustrates the detection method of spherical aberration detection signal and control method thus.

In running order in above-mentioned focus adjustment, as shown in Figure 2, shaven head 5 light beams that sent are by the refraction of the matrix part 21 of CD 20, and outer Monday side beam at focus B, and interior Monday side beam at focus C light harvesting.

In when, spherical aberration not taking place on the information recording surface of CD 20, outer Monday side beam focus B; Interior Monday, the focus C of side beam was simultaneously consistent with focus A, and, along with the increase that spherical aberration influences, focus B and focus C leave mutually, and two focuses are in simultaneously information recording surface that should pack is become defocus condition.

As shown in figure 11, as the spherical aberration testing agency 31 of spherical aberration testing agency function detect respectively this outer Monday side beam be subjected to the spherical aberration influence amount (defocus amount of focus B) and interior Monday side beam be subjected to the amount (defocus amount of focus C) that spherical aberration influences; So, detect signal corresponding to the amount of spherical aberration that occurs in light beam pack position.More particularly, calculate as outer Monday side focus error signal maker 44 output signals outer Monday the side focus error signal and as interior Monday side focus error signal maker 45 output signals interior Monday the side focus error signal method, generation is corresponding to the spherical aberration detection signal of the signal that occurs in light beam pack position amount of spherical aberration.

At microcomputer 8, carry out phase compensation as the spherical aberration detection signal input of the output signal of spherical aberration detector 31; The filtering operation of gain compensation etc. generates: be used for the spherical aberration correcting signal that spherical aberration is corrected.Microcomputer 8 with focus adjustment body function and spherical aberration control gear function carries out the separating of spherical aberration correcting signal frequency behind the filtering operation; With spherical aberration correcting signal DC composition mutually the optical beam expander of response slightly drive with circuit 32 drive signal, the approximate drive signal that becomes 0 position sends stepping motor (with reference to Figure 12 (b)) to even spherical aberration correcting lens 15 moves to the DC composition of spherical aberration correcting signal.Accept the stepping motor 35 moving sphere aberration correcting lenses 15 (time t1) of this drive signal, correct, so that make the DC composition of spherical aberration almost become 0.

Then, microcomputer 8 is to the accurate drive signal (time t2) that drives with circuit 33 output moving sphere aberration correcting lenses 15 of optical beam expander, shown in Figure 12 (c), in the stepping motor 35 immedicable approximate 0 the drive signal that becomes of AC composition that is included in the spherical aberration correcting signal promptly; Accept the spherical aberration of this signal and correct regulator 34 moving sphere aberration correcting lenses 15, correct control, become 0 so that spherical aberration is approximate, i.e. focus B; Focus C unanimity (is focus B; Focus C is simultaneously near focus A).

Specifically, the spherical aberration detection signal of the output signal of 8 pairs of spherical aberration detectors 31 of microcomputer carries out filtering operation.The DC components utilising optical beam expander of the spherical aberration detection signal after the filtering operation slightly drives with circuit 32; Stepping motor 35 comes drive ball surface aberration correcting lens 15, corrects control, makes focus A; B; The C unanimity.In addition, AC components utilising optical beam expander is accurate drives with circuit 33; Spherical aberration is corrected regulator 34 and is come drive ball surface aberration correcting lens 15, corrects control, makes focus A; B; The C unanimity.

In the present embodiment, DC composition as for the spherical aberration correcting signal, optical beam expander slightly drives with circuit 32 it approximate is become the method that 0 drive signal sends stepping motor 35 to, and stepping motor 35 moving sphere aberration correcting lenses 15 carry out the spherical aberration of DC composition and correct; AC composition as for the spherical aberration correcting signal, optical beam expander is accurate to be driven with circuit 33 its approximate drive signal of 0 of becoming is sent to spherical aberration rectification regulator 34, spherical aberration is corrected regulator 34 moving sphere aberration correcting lenses 15, carries out the spherical aberration of AC composition and corrects; Therefore, in order to realize the record to the more densification of CD 20, (such as NA is more than 0.8 even utilize the ratio bigger CD of NA in the past; And then more than 0.85), responsiveness is good, can realize that the spherical aberration of wide ranges is corrected control.

In addition, utilize in the control of stepping motor 35 of the thick drive signal of optical beam expander of Figure 12 (b), if the spherical aberration correcting signal of AC composition spherical aberration correcting signal that is lower than CD 20 gyro frequencys and DC composition is sent to optical beam expander slightly to be driven with circuit 32, and handle is higher than the AC composition spherical aberration correcting signal of CD 20 gyro frequencys and the spherical aberration correcting signal of DC composition is sent to the accurate usefulness circuit 33 that drives of optical beam expander, then, chase after from slow-footed stepping motor 35 to the influence in uneven thickness of the matrix part 21 of each circle and do not show excessive responsiveness, and can chase after matrix part variation in thickness from radial direction, more can improve spherical aberration and correct the precision of control, the responsiveness that spherical aberration is corrected becomes better.

" embodiment 2 "

Figure 13 is the block diagram of expression embodiment 2 CD device structure.Figure 14 is the spherical aberration correcting signal oscillogram of the interlayer of present embodiment when moving.Figure 15 is that the spherical aberration of the interlayer of present embodiment when moving corrected sequential flowchart.The parts that are same as prior art, embodiment 1 among these figure are attached with identical symbol with part, omit its explanation.

Constitute the interlayer travel mechanism that drives focalizer by microcomputer 8 and focalizer driving circuit 9.Among Figure 13, activation point selection portion 13 is taken out the target drives position from activation point preservation portion 14, outputs to optical beam expander and slightly drives with circuit 32.

In addition and embodiment 1 same, utilize outer Monday the side focus error signal and interior Monday side focus error signal sum focus error signal; Outer Monday the side focus error signal and interior Monday the side focus error signal the spherical aberration detection signal of difference carry out focus adjustment and spherical aberration control.

Spherical aberration when moving in conjunction with the interlayer of the embodiment 2 of Figure 13 to Figure 15 explanation as above-mentioned structure is corrected control.

As Figure 14 (c); (d) shown in, when interlayer moved, at first in the t1 time, microcomputer 8 stopped basis from spherical aberration detector 31 output signals, to the accurate output that drives with circuit 33 of optical beam expander, and stop corresponding to output from focus error signal maker 36 to focalizer driving circuit 9.Like this, the rectification control and the focus adjustment of spherical aberration are not worked, and (the step S1 of Figure 15 promptly quits work; S2).

Then, shown in Figure 14 (d) and order in the past same, till time t2, the driving command of mobile usefulness (the step S3 of Figure 15) between focalizer driving circuit 9 output layers.If the driving command that between time t2 end layer, moves, meanwhile, microcomputer 8 is removed stopping of focalizer driving circuit 9 outputs, i.e. stopping according to 36 outputs of focus error signal maker, shown in Figure 14 (d), the focus adjustment that reruns (the step S4 of Figure 15).

Then, till time t3, wait for (the step S5 of Figure 15) after focus adjustment stable, it is that the activation point preservation portion shown in Figure 13 14 of information of the activation point of the in store relevant spherical aberration correcting lens 15 that is suitable for the moving target information record surface takes out for information about from activation point preservation portion 14 that microcomputer 8 utilizes activation point selection portion 13, optical beam expander is slightly driven with circuit 32, and the drive signal (shifted signal) that shown in Figure 14 (b) spherical aberration correcting lens 15 is moved to activation point outputs to stepping motor 35.Thus, stepping motor 35 is driven, shown in Figure 14 (a), and approximate 0 (the step S6 of Figure 15 that becomes of the DC composition of spherical aberration signal; S7).

At last, microcomputer 8 is the accurate driving of time t4 relieving light beam expander stopping with circuit 33 outputs, by shown in Figure 14 (c), the correcting signal that output is failed to correct by stepping motor 35 (being to be the AC composition of spherical aberration signal in the present embodiment) (the step S8 of Figure 15) utilizes spherical aberration to correct the rectification control that regulator 34 restarts spherical aberration.

In addition, the following formation focus adjustment time; Spherical aberration control stand-by time; And optical beam expander slightly drives the method with the drive signal output time of circuit etc., and more Gao Su interlayer access becomes possibility.

Figure 16 is condenser lens and the information faces L0 of the interlayer of two-layer CD when moving; The oscillogram of L1 position and each signal, below, describe in conjunction with Figure 16.

At first, set the arbitrarily magnetic track of beam flying at information faces L0.At this state, during the data of regenerating information face L1, at first focus adjustment and spherical aberration are corrected control and are not worked, and stop promptly that (time a).Then, after focalizer driving circuit 9 provides driving command, utilize activation point selection portion 13 from activation point preservation portion 14 shown in Figure 13, be to take out for information about in store relevant being suitable for, slightly drive to export to optical beam expander and make spherical aberration correcting lens 15 move to the drive signal (time b) of the activation point of taking-up with circuit 32 as the activation point preservation portion 14 of the activation point information of the spherical aberration correcting lens 15 of another information faces of destination layer (being information faces L1 in the present embodiment).

Thus, along with the focusing of object lens 1 from information faces L0 near information faces L1, stepping motor 35 moves and makes the spherical aberration that moves generation thus become minimum, promptly, more near the spherical aberration correct amount that becomes benchmark among the information faces L1, therefore, can reduce the FE signal that causes because of the spherical aberration cataclysm in focus on shifting or the influence of CD 20 total reflection light quantities, can not hinder and focus on the stability that shifts.Move to after the information faces L1, idle focus adjustment becomes conducting (ON) (time c) at once afterwards, even spherical aberration is controlled at conducting, if the focus adjustment instability, then spherical aberration control is also unstable, therefore, such as observing the FE signal on one side, if FE signal pack in specialized range, assert then that focus adjustment is stable, make idle spherical aberration control become conducting (time d).

Thus, mobile stepping motor 35 (particularly the spherical aberration correcting lens 15), therefore the change of the spherical aberration of generation, can realize the control transformation of the spherical aberration of each stable layer when moving to suppress interlayer, its effect is big.

As mentioned above, the spherical aberration DC composition change that takes place when utilizing thick drive system (stepping motor 35) rectification to move for interlayer can realize the spherical aberration rectification control corresponding to the wide ranges of two-layer or more multi-layered CD.

" embodiment 3 "

Figure 17 is the block diagram of the expression embodiment of the invention 3 CD device structure.Figure 18 is that the expression spherical aberration during the radial direction of embodiment 3 moves is corrected the figure of drive signal waveform.Figure 19 is the process flow diagram of the expression spherical aberration rectification order of the radial direction of embodiment 3 when moving.Parts, the part that among these figure and technology in the past, embodiment 1 are identical is attached with identical symbol and omit its explanation.

In the present embodiment, shaven head 5 is as holding integratedly: the light source 3 as the light beam irradiates body function of illumination beam; The light beam pack at object lens 1 as pack mechanism as the CD 20 of information carrier; In order to change the pack position of light beam, the focalizer 2 that object lens 1 are moved on perpendicular to the information faces of CD 20 as first regulator; The spherical aberration that takes place on the pack position for the light beam that changes by object lens 1 pack is as the spherical aberration correcting lens 15 of spherical aberration changeable mechanism function; The stepping motor 35 of moving sphere aberration correcting lens 15; The spherical aberration of moving sphere aberration correcting lens 15 is corrected regulator 34; And the catoptrical light accepting part 37 that connects of accepting the CD 20 of light beam.

Shaven head 5 transport platform 60 that can utilize as the searching mechanism function move on the radial direction of CD 20, and in addition, transport platform 60 is driven by the output signal (drive signal) of transport platform driving circuit 62.

In addition and embodiment 1 same, according to outer Monday the side focus error signal and interior Monday side focus error signal sum focus error signal (by the signal of focus error signal maker 36 outputs); Outer Monday the side focus error signal and interior Monday the side focus error signal the spherical aberration detection signal (signals of spherical aberration detector 31 outputs) of difference carry out focus adjustment and spherical aberration control.

In conjunction with Figure 17; Figure 18; Figure 19 illustrates the spherical aberration rectification control when as above the radial direction of the embodiment 3 of structure moves.Shown in Figure 18 (c), in the retrieval in the moving of radial direction, at first, at the time t1 that does not carry out the tracking Control state, microcomputer 8 stops the accurate output that drives with circuit 33 of optical beam expander, i.e. output of exporting according to spherical aberration detector 31, make spherical aberration correct regulator 34 idle methods, stop the rectification control (the step S1 of Figure 19) of spherical aberration, shown in Figure 18 (d), till time t2, to the drive signal (the step S2 of Figure 19) of the mobile transport platform of transport platform driving circuit 62 outputs.

Transport platform driving circuit 62 moves the transport platform 60 that shaven head 5 is housed according to the drive signal of the transport platform that microcomputer 8 is transmitted to the radial direction of CD 20.Then, at time t3,8 pairs of optical beam expanders of microcomputer slightly drive with circuit 32 output drive signals, so that approximate 0 the signal shown in Figure 18 (b) that becomes of the DC composition of spherical aberration detection signal.Stepping motor 35 is slightly to drive the drive signal that is transmitted with circuit 32 according to optical beam expander to drive, and microcomputer 8 waits for that stepping motor 35 moves to position (the step S3 of Figure 19 of regulation; S4).

At next time t4, microcomputer 8 releasings are exported corresponding to spherical aberration detector 31, stop to the accurate output that drives with circuit 33 of optical beam expander, but the correcting signal shown in Figure 18 (c) (being to be the AC composition of spherical aberration signal in the present embodiment) (the step S5 of Figure 19) that output fails to correct at stepping motor 35 utilizes spherical aberration to correct the rectification control that regulator 34 restarts spherical aberration.

In addition, following formation spherical aberration control stand-by time and optical beam expander slightly drive the method with the drive signal output time of circuit, and more Gao Su radial direction access becomes possibility.

Figure 20 be radial direction when moving object lens 1 and the matrix part pressure of CD 20 changes and the oscillogram of each signal, below, describe in conjunction with Figure 20.At first, suppose beam flying in optical interrogation 20 Monday side magnetic track arbitrarily.Under this state, during the data of outer Monday of the side of regenerating, at first, microcomputer 8 makes tracking Control and spherical aberration correct control and does not work, and promptly quitting work, (time a).Then, after transport platform driving circuit 62 provides driving command, microcomputer 8 is in order to move to (light beam) to be adapted to the activation point of the spherical aberration correcting lens 15 of radius of target position matrix part pressure, optical beam expander is slightly driven with circuit 32 transmission spherical aberration correcting signals, and optical beam expander slightly drives with the drive signal (offset signal) (time b) of circuit 32 outputs corresponding to transmission spherical aberration correcting signal.

Thus, along with transport platform 60 from interior Zhou Yidong near periphery, mobile stepping motor 35, so that because this moves the spherical aberration minimum that is taken place, the promptly more close amount of spherical aberration that becomes benchmark as the target circumferential position, therefore, can reduce the trail-and-error signal that radial direction causes owing to the spherical aberration cataclysm in moving or the influence of FE signal, can not hinder radial direction move after soon the stability of the work that retracts of tracking Control.

Move to after the periphery of target, stop tracking Control (time C), continue to remove stopping of spherical aberration control, even conducting, if the tracking Control instability, then, tracking Control might be unstable, therefore, such as observing the trail-and-error signal on one side, if trail-and-error signal pack within the limits prescribed, then microcomputer 8 just judges that tracking Control is stable, remove stopping of spherical aberration control, carry out conducting (time d).Thus, when radial direction moves, can realize the more stable spherical aberration conversion of each radius, its effect is big.

As mentioned above, utilize thick drive system (stepping motor 35) to carry out the rectification of the spherical aberration DC composition that radial direction takes place when moving, the spherical aberration that can absorb the in uneven thickness of CD 20 or paste uneven wide ranges is corrected control.

" embodiment 4 "

Figure 21 is the block diagram of the CD device structure of the expression embodiment of the invention 4.Figure 22 is the oscillogram that the spherical aberration of expression embodiment 4 optical disc apparatus interlayers when moving corrected drive signal.Figure 23 is the process flow diagram of the expression spherical aberration rectification order of expression embodiment 4 interlayers when moving.Parts, the part that among these figure and technology in the past, embodiment 1 are identical is attached with identical symbol and omit its explanation.

When microcomputer 8 has preservation corresponding to the side-play amount preservation portion 68 of the side-play amount of each information faces of CD 20, also has the side-play amount selection portion 67 that body function is replaced in skew that has as the skew additional mechanism providing additional operation.Microcomputer 8 utilizes side-play amount selection portion 67 from the save value of wanting that side-play amount preservation portion 68 takes out corresponding to CD 20 each information faces, replaces with the side-play amount of taking-up.Utilize after the additive operation of side-play amount that adder calculator 69 replaces and spherical aberration correcting signal, with it as to the accurate drive signal that drives with circuit 33 of optical beam expander, to be applied on the spherical aberration correcting lens 15 as skew.

Amplifying accurate the driving with circuit 33 of optical beam expander of the control output current of microcomputer 8 comes the drive ball surface aberration to correct regulator 34.The elastic body of laminated spring etc. is installed on the spherical aberration correcting lens 15, corrects the masterpiece that regulator 34 applies signal corresponding to spherical aberration and be used for this laminated spring.As mentioned above, be applied on the laminated spring of support ball surface aberration correcting lens 15, therefore, can finely move this spherical aberration correcting lens 15 corresponding to the power of each information faces side-play amount.

In addition and embodiment 1 same, outer Monday the side focus error signal and interior Monday side focus error signal sum generate focus error signal; Outer Monday the side focus error signal and interior Monday the side focus error signal difference generate the spherical aberration detection signal.

Spherical aberration when illustrating that in conjunction with Figure 21 to 23 as above the interlayer of the embodiment 4 of structure moves is corrected control.

In the present embodiment and embodiment 1 same, focus adjustment is in running order, at microcomputer 8, carries out the filtering operation of phase compensation and gain compensation etc. from the spherical aberration detection signal input of spherical aberration detector 31 output there.

Microcomputer 8 utilizes side-play amount selection portion 67, is kept at the selection corresponding to the side-play amount of moving target information face in side-play amount preservation portion 68 side-play amounts; Replace.Then, microcomputer 8 utilizes adder calculator 69, the additive operation between side-play amount of replacing and the spherical aberration correcting signal behind the filtering operation, and the signal of additive operation driven with circuit 33 outputs to optical beam expander is accurate.Optical beam expander is accurate to be driven with the spherical aberration correcting signal of circuit 33 after according to the skew additive operation and carries out the spherical aberration rectification.

When interlayer moves, at first, as Figure 22 (b); (d) shown in, at time t1, microcomputer 8 makes focus adjustment and spherical aberration correct control and does not work and promptly stop (the step S1 of Figure 23; S2) and same order in the past, shown in Figure 22 (d), till time t2, to focalizer driving circuit 9 output orders (the step S3 of Figure 23).Then, moved processing if finish with same in the past interlayer, meanwhile, restart focus adjustment (the step S4 of Figure 23), simultaneously, the side-play amount selection portion 67 of microcomputer 8 is taken out the accurate side-play amount of using with the target mobile message record surface shown in Figure 22 (c) of circuit 33 that drives of optical beam expander from side-play amount preservation portion 68, and what be added in the accurate drive signal of optical beam expander carries out additive operation shown in Figure 22 (b).

Thus, the accurate driving of optical beam expander uses circuit 33 according to the accurate drive signal of optical beam expander, and the drive ball surface aberration is corrected regulator 34, makes approximate 0 (the step S5 of Figure 23) that become of DC composition of spherical aberration detection signal.By the time after focus adjustment is stablized (the step S6 of Figure 23), at time t3, microcomputer 8 does not have the spherical aberration correcting signal that can correct with side-play amount to accurate the driving with circuit 33 outputs of optical beam expander shown in Figure 22 (b), remove spherical aberration and correct stopping of regulator 34, restart the rectification control (the step S7 of Figure 23) of spherical aberration.

Like this, the DC composition of the spherical aberration that takes place when interlayer is moved is added in the additive operation method of the skew of accurate drive system (spherical aberration is corrected regulator 34), can realize spherical aberration rectification control stable and that the rectification precision is high.

In addition, measure the DC composition of the spherical aberration in the stipulated time, its mean value is added in now the method for computing makes spherical aberration correct the controlled target position and becomes the best by the side-play amount of the selected side-play amount preservation of side-play amount selection portion 67 portion 68, more can improves to chase after from precision.

" embodiment 5 "

Figure 24 is the block diagram of the CD device structure of the expression embodiment of the invention 5.Figure 25 (a) to (d) is the oscillogram that the spherical aberration of expression embodiment 5 optical disc apparatus interlayers when moving corrected drive signal etc.Parts, the part that among these figure and technology in the past, embodiment 1 are identical is attached with identical symbol and omit its explanation.

The microcomputer 8 of present embodiment shown in Figure 24 has dead zone generating unit 70.The signal that generating unit 70 gain acceptance in adjusters 66 in dead zone are exported when the absolute value of this signal becomes setting, interdicts its signal, and work makes it not to be sent to optical beam expander and slightly drives with circuit 32.

Stepping motor 35 is to utilize optical beam expander that electric current amplifies is carried out in the control output of microcomputer 8 slightly to drive with circuit 32 and drive.

Utilize stepping motor 35 spherical aberration correcting lens 15 to move in a wider context.In addition and embodiment 1 same, by outer Monday the side focus error signal and interior Monday side focus error signal sum generate focus error signal, and outer Monday the side focus error signal and interior Monday the side focus error signal difference generate the spherical aberration detection signal.

The spherical aberration that the embodiment 5 of above structure is described in conjunction with Figure 24 and Figure 25 is corrected control.

In the present embodiment and embodiment 1 same, when focus adjustment is in running order, at microcomputer 8, there, carry out the filtering operation of phase compensation and gain compensation etc. by the spherical aberration detection signal input of spherical aberration detector 31 output.Spherical aberration correcting signal behind the filtering operation of the dead zone generating unit 70 gain acceptance in adjustment parts 66 in the microcomputer 8, when the absolute value of its signal surpasses setting, its signal is outputed to optical beam expander slightly to be driven with circuit 32, become setting when following at the absolute value of its signal, the output of obstruction signal.

Will narrate as the back, at time t1, in order to drive stepping motor, the spherical aberration correcting signal after the filtering operation has the waveform shown in Figure 25 (a).In time t1～t2, because the driving of stepping motor can know that the spherical aberration detection signal diminishes.

Figure 25 (d) is the output (the spherical aberration detection signal after handle in the dead zone) of expression dead zone generating unit 70.This spherical aberration detection signal outputs to optical beam expander and slightly drives with circuit 32, and optical beam expander slightly drives the signal of spherical aberration correcting signal output shown in Figure 25 (b) after using circuit 32 to handle according to the dead zone, carries out the rectification control of spherical aberration.

Shown in Figure 25 (c), in time t1～t2, stepping motor 35 is to be driven with circuit by thick driving of optical beam expander, corrects to carry out spherical aberration., shown in Figure 25 (d), the absolute value of spherical aberration correcting signal becomes below the setting after time t2, and output is interdicted, and therefore, shown in Figure 25 (c), can not be corrected by stepping motor 35.

Like this, when the variation of spherical aberration correcting signal (or spherical aberration detection signal) is small, can reduces because of what stepping motor 35 tetchiness responses caused and cross error.Particularly, disk thickness slowly changes and spherical aberration when changing with low frequency in the spiral work, and slick and sly chasing after from control (whether controlling) becomes possibility, and its effect is big.

" embodiment 6 "

Figure 26 is the block diagram of the CD device structure of the expression embodiment of the invention 6.Figure 27 is the sectional drawing for the light beam of the spherical aberration detection that present embodiment is described.In the present embodiment optical disc apparatus, it is same with embodiment 1 connecing light accepting part 37 or prime amplifier 12, has the structure of Figure 10 and Figure 11.

Among Figure 26, be to come detectedly as photocurrent, and be sent to prime amplifier 12 corresponding to what accept light quantity connecing reflected light that light accepting part 37 accepts from CD 20.Prime amplifier 12 carries out the current-voltage conversion, and the output voltage corresponding to photocurrent is sent to focus error signal maker 36 and spherical aberration detector 31.

As the focus error signal maker 36 of pack state detection mechanism function,, detect the signal on CD 20 information faces 29 corresponding to the pack state according to as the signal that connects light accepting part 37 that connects the light accepting part function.Particularly,, detect signal corresponding to the pack state according to the output signal of prime amplifier 12, generate by shaven head 5 outputs by the relevant rub-out signal of vertical direction between the light beam spot of light harvesting and the CD 20.

Spherical aberration is corrected the spherical aberration correcting lens 15 that regulator 34 drives as spherical aberration changeable mechanism function.Particularly, adjust the method for two compound lenss that constitute spherical aberration correcting lens 15, can change the spherical aberration of light beam spot.

Among the embodiment that present embodiment and back will be narrated, utilize spherical aberration correcting lens 15, still, the invention is not restricted to these as the spherical aberration changeable mechanism.Also can utilize liquid crystal to wait and change optical range (optical path length); And correct the element of spherical aberration thus.The spherical aberration changeable mechanism of form is to drive by applying the circuit that is adapted to liquid crystal voltage like this.

Spherical aberration detector 31 as spherical aberration testing agency function, according to as the signal that connects light accepting part 37 of accepting the optical mechanism function, detect the spherical aberration states that light beam spot took place that generates on the information faces 29 of CD 20, output is corresponding to the signal (to call spherical aberration signal in the following text) of spherical aberration states.

But adjustment of focusing system and spherical aberration control system interfere with each other.Particularly, occur on the spherical aberration signal, occur on the FE signal corresponding to the distance change till the focus of the object lens of spherical aberration correct amount corresponding to the detection error that defocuses.Therefore, utilize spherical aberration rectification portion 132 to amplify FE signal specified multiple, and be added in the method for spherical aberration signal, get rid of and follow the influence that defocuses spherical aberration signal.Thus, cut off the loop of disturbing between adjustment of focusing system and the spherical aberration control system and become possibility.

The spherical aberration signal of correcting according to the FE signal is sent to optical beam expander driving circuit 133 by spherical aberration control part 135.Therefore, spherical aberration corrects that regulator 34 is subjected to is the control corresponding of the spherical aberration signal of correcting according to the FE signal.In addition, spherical aberration control part 135 has phase compensation; The wave filter of gain compensation etc., stability ball surface aberration control system.In addition, optical beam expander driving circuit 133 is driving circuit that spherical aberration is corrected regulator 34.

The generation method of FE signal is described in conjunction with Figure 10.

Detecting lens 46 is folded light beams of light harvesting CD 20.Polarization beam splitter 47 is divided into two to folded light beam.First shadow shield 48 is according to the light beam of predetermined radius blocking interior Monday of the side of folded light beam.Outer Monday, the light accepting part 40 that connects of side was to accept by being transformed to photocurrent after the light beam behind first shadow shield 48.Second shadow shield 49 is the light beams in the blocking light beam predetermined radius outside, and interior Monday, the light accepting part 41 that connects of side was to accept by being transformed to photocurrent after the light beam behind second shadow shield 49.

Particularly, as shown in figure 10, its structure is to connect the folded light beam that light accepting part 37 utilizes polarization beam splitter 47 to separate by the CD 20 that detects lens 46, one side utilizes 48 light beams that take out periphery of first shadow shield, the opposing party is the light beam that utilizes week in 49 taking-ups of second shadow shield, and utilization outer Monday of side joint light accepting part 40 respectively; Interior Monday, the side joint light accepting part 41 detected.

Present embodiment connect light accepting part 37; Focus error signal maker 36; Spherical aberration detector 31 and prime amplifier 12 also have structure shown in Figure 11.

Shown in Figure 11 outer Monday, the side joint light accepting part 40; Interior Monday, the side joint light accepting part 41 was divided into A respectively; B; C; Four zones of D generate respectively corresponding to the photocurrent that detects light quantity, output to the I/V converter 42a～42d of prime amplifier 12 inside; I/V converter 43a～43d.By I/V converter 42a～42d; I/V converter 43a～43d is transformed to the signal of current-voltage, and is sent to outer Monday of side focus error signal maker 44 respectively; Interior Monday, side focus error signal maker 45.

Here, the code track length direction is meant the tangential direction of the magnetic track 28 of CD 20, and the CD radial direction is meant the direction perpendicular to the magnetic track 28 of CD 20.Therefore, obtain the computing that I/V converter 42a and I/V converter 42c sum deduct I/V converter 42b and I/V converter 42d sum outside Monday in the side focus error signal maker 44, utilize the astigmatism method to obtain outer Monday of side focus error signal as the FE signal; Obtain the computing that I/V converter 43a and I/V converter 43c sum deduct I/V converter 43b and I/V converter 43d sum in the side focus error signal maker 45 in interior Monday, utilize the astigmatism method to obtain interior Monday of side focus error signal as the FE signal.

The actual focus error signal that is used in the present embodiment of focus adjustment be this outer Monday the side focus error signal and interior Monday side focus error signal maker 36 in the signal of additive operation.That is, (I/V converter 42a+I/V converter 42c)-(I/V converter 42b+I/V converter 42d) can be write as ((I/V converter 42a+I/V converter 43a)+(I/V converter 42c+I/V converter 43c))-((I/V converter 42b+I/V converter 43b)+(I/V converter 42d+I/V converter 43d)) with (I/V converter 43a+I/V converter 43c)-(I/V converter 43b+I/V converter 43d) sum.

Thereby the focus error signal of present embodiment is slightly different with the focus error signal by the astigmatism method in the past, but its characteristic is of equal value.

Therefore, utilization is same as the method and the device in the past of the FE signal of these focus error signal maker 36 output signals, and light beam spot may be controlled to: the pack state that the information faces 29 of CD 20 is in regulation.

Below, the generation method (detection method) of spherical aberration signal is described.

Spherical aberration signal be outside spherical aberration detector 31 carries out Monday the side focus error signal and interior Monday side focus error signal subtraction signal.

In conjunction with Figure 27 spherical aberration signal is described.Figure 27 (a) is the state of representing the distance the best from the optical disc surface to the information faces and spherical aberration not taking place on information faces.Figure 27 (b) is thin and state generation spherical aberration on information faces of the above-mentioned distance of expression.

Above-mentioned focus adjustment is in duty, shown in Figure 27 (a), from of matrix part 21 refractions of shaven head 5 luminous light beams at CD 20, outer Monday side light beam at focus B; Interior Monday side light beam at focus C light harvesting.Position A is positioned on the straight line that connects focus B and focus C, and on information faces 29.Spherical aberration does not take place on the information faces 29 of CD 20, therefore, outer Monday side beam focus B with interior Monday side beam focus C simultaneously consistent with position A.That is, off normal that to put equidistant of A consistent with beam wave surface.

Shown in Figure 27 (b), if be equivalent to the thickness attenuation of optical disc surface to the matrix part 21 of information faces distance, then the influence of spherical aberration becomes big.That is focus B; Focus C leaves mutually, and to information faces 29 position A that should pack, two focuses become defocus condition simultaneously.But focus adjustment work is so that make above-mentioned outer Monday of side focus error signal and the focus error signal (output signal of focus error signal maker 36) of interior side focus error signal additive operation Monday is approximate becomes 0.Therefore, position A is consistent with information faces 29.At this moment, equidistant of beam wave surface and position A inconsistent.Here, when solid line is represented spherical aberration takes place interior Monday side and outer Monday side beam, when dotted line is represented spherical aberration not to take place interior Monday side with outer Monday of side beam.In addition, shown in Figure 27 (a), optical disc surface is during to the thickness thickening of information faces, and focus B and focus C leave equally mutually, and two focuses of information faces 29 position A that should pack to light beam are in defocus condition simultaneously.

As shown in figure 11, as the spherical aberration detector 31 of spherical aberration testing agency function detect amount of spherical aberration (defocus amount of focus B) that the light beam of this of side is subjected to outer Monday respectively and in this Monday side the amount of spherical aberration (defocus amount of focus C) that is subjected to of light beam, detect the signal that occurs in light beam pack position according to this corresponding to amount of spherical aberration.More specifically, calculate as outer Monday side focus error signal maker 44 output signal outer Monday the side focus error signal with as interior Monday side focus error signal maker 45 output signal interior Monday the side focus error signal the method for difference, generation occurs in the spherical aberration signal corresponding to the signal of amount of spherical aberration of light beam pack position.

Among Figure 26, in spherical aberration control part 135, carry out the phase compensation of above-mentioned spherical aberration signal; The filtering operation of gain compensation etc.Thereafter, spherical aberration control part 135 is exported the output signal that is used for moving sphere aberration correcting lens 15 to optical beam expander driving circuit 133, accepts the spherical aberration of this drive signal and corrects regulator 34 moving sphere aberration correcting lenses 15.That is, correct control,, that is, make focus B so that spherical aberration becomes 0; Focus C unanimity just makes focus B; Focus C is simultaneously near A.Yet exist: above-mentioned adjustment of focusing system and spherical aberration control system interfere with each other and the mutual problem of unstable of control system.

In conjunction with Figure 49; The oscillogram explanation adjustment of focusing system of Figure 50 and the interference of spherical aberration control system.At first, illustrate that adjustment of focusing system gives the influence of spherical aberration signal.In addition, suppose that the spherical aberration control system is in work.Figure 49 (a) is expression adjustment first shadow shield 48 and second shadow shield 49 are cut apart the light beam of pack on 50% radial location of the beam radius of accepting a appearance.Figure 49 (b) is expression outer Monday of a side focus error signal, and Figure 49 (c) is expression interior Monday of a side focus error signal, and Figure 49 (d) is the expression focus error signal, and Figure 49 (e) is an expression spherical aberration detection signal.In addition, outer Monday of the side focus error signal of above-mentioned Figure 49 (b) deduct Figure 49 (c) interior Monday the side focus error signal signal be exactly the spherical aberration detection signal of Figure 49 (e).The longitudinal axis is represented each voltage of signals, and transverse axis is represented to defocus.

Figure 50 (a) is expression adjustment first shadow shield 48 and second shadow shield 49 are cut apart the light beam of pack on 75% radial location of the beam radius of accepting a appearance.Figure 50 (b) is expression outer Monday of a side focus error signal, and Figure 50 (c) is expression interior Monday of a side focus error signal, and Figure 50 (d) is the expression focus error signal, and Figure 50 (e) is an expression spherical aberration detection signal.The longitudinal axis is represented each voltage of signals, and transverse axis is represented to defocus.

Shown in Figure 49 (a), when accepting to cut apart on 50% the radial location of beam radius of light, outer Monday side light amount ratio in Monday the sidelight amount many, therefore, Figure 49 (b) outer Monday the side focus error signal amplitude greater than Figure 49 (c) interior Monday the side focus error signal amplitude.Its result, though spherical aberration is certain, owing to defocus, the spherical aberration detection signal is changing.In addition, spherical aberration signal is to the focus error signal of 49 (d), because that the polarity that defocuses becomes is identical (to the phase place of FE signal, 0 degree slow).

On the other hand, shown in Figure 50 (a), when accepting to cut apart on 75% the radial location of beam radius of light, outer Monday side light amount ratio in Monday the sidelight amount few, therefore, Figure 50 (b) outer Monday the side focus error signal amplitude less than Figure 50 (c) interior Monday the side focus error signal amplitude.Its result, though spherical aberration is certain, owing to defocus, the spherical aberration detection signal is changing.In addition, spherical aberration signal is to the focus error signal of Figure 50 (d) and since the polarity that defocuses become on the contrary (to the phase place of FE signal, 180 spend slow).

The above-mentioned skew owing to defocusing the spherical aberration signal of generation is that the spherical aberration control system is worked as external disturbance.

Below, describe the external disturbance of moving of spherical aberration correcting lens 15 in detail to adjustment of focusing system in conjunction with Figure 53.Figure 53 represents that spherical aberration correcting lens position is to the influence mode chart of object lens to focusing distance.Figure 53 (a) expression optical disc surface is to thickness the best of information faces; And the state of spherical aberration does not take place on information faces.Equally, the thick situation of Figure 53 (b) expression thickness.In addition, adjustment of focusing system operate as normal; And utilize spherical aberration correcting lens 15 to correct the state of the spherical aberration that takes place on the information faces.The situation of Figure 53 (c) expression thin thickness.And Figure 53 (b) is same, utilizes spherical aberration correcting lens 15 to correct the state of the spherical aberration that takes place on the information faces.

Shown in Figure 53 (b), along with the thickness thickening of matrix part, the interval W of spherical aberration correcting lens 15 narrows down.In addition, object lens 1 becoming far to focus apart from Z.

In addition, shown in Figure 53 (c), if the matrix part attenuation, W broadens at interval, becomes near apart from Z.Because the interval W of spherical aberration correcting lens 15 changes, changing apart from Z.That is, this variation apart from Z is that external disturbance as adjustment of focusing system works.

Below, illustrate: adjustment of focusing system gives the method for removing of the influence of spherical aberration signal.In addition, spherical aberration rectification portion 132 is for getting rid of the branch of this influence.The work of spherical aberration rectification portion 132 is described in conjunction with Figure 28.The output of Figure 28 (a) expression focalizer driving circuit 9.The output of Figure 28 (b) expression focus error signal maker 36, the output of Figure 28 (c) expression spherical aberration rectification portion 132, the output of Figure 28 (d) expression spherical aberration detector 31, the spherical aberration signal after Figure 28 (e) expression is corrected.

In addition, apply the state of the external disturbance of the frequency also higher on the expression adjustment of focusing system than adjustment of focusing system frequency band.Shown in Figure 28 (a), the output of focalizer driving circuit 9 becomes corresponding to the drive signal that applies external disturbance.In addition, defocus amount becomes the waveform corresponding to Figure 28 (a).As mentioned above, spherical aberration signal becomes the waveform shown in Figure 28 (d) corresponding to the defocus amount variation level.Figure 28 (d) expression adjustment of focusing system gives the external disturbance of spherical aberration signal.When microcomputer 8 is worked in focus adjustment, utilize and amplify FE signal feeding multiple (K doubly) in the spherical aberration rectification portion 132, and be added in the method for spherical aberration signal, shown in Figure 28 (e), get rid of the influence of following the spherical aberration signal that defocuses.

Below, the determining method of the magnification K of spherical aberration rectification portion 132 is described.Figure 29 is the block diagram for the expression CD device structure of the spherical aberration rectification portion magnification learning method that present embodiment is described.Optical disc apparatus shown in Figure 29 is the additional device that is used for the branch of magnification K study on optical disc apparatus shown in Figure 1.Therefore and the jack per line branch in Figure 29 jack per line block list diagrammatic sketch 1.Focusing on test signal generator 50 is that the focus drive signal that focus adjustment portion 17 is exported adds test signal.First amplitude detector 51 detects the amplitude of spherical aberration signal.It is magnifications that the amplitude detecting signal of seeking and visiting first amplitude detector 51 becomes minimum spherical aberration rectification portion 132 that spherical aberration is corrected study portion 52.

Waveform in conjunction with Figure 30 illustrates its work.The output of Figure 30 (a) expression focalizer driving circuit 9.Equally, the output of Figure 30 (b) expression focus error signal maker 36, the magnification of Figure 30 (c) expression spherical aberration rectification portion 132, the output of Figure 30 (d) expression spherical aberration rectification portion 132, the output of Figure 30 (e) expression spherical aberration detector 31, spherical aberration signal after Figure 30 (f) expression is corrected, the output of Figure 30 (g) expression first amplitude detector 51.In addition, shown in Figure 50 (a), the situation cut apart on 75% radius of beam radius of light is accepted in expression.The longitudinal axis is represented each voltage of signals, the transverse axis express time.Spherical aberration is corrected the magnification of 52 setting spherical aberration rectification portions 132 of study portion promptly as COEFFICIENT K, sets Ka on the time t0 in the early stage.

When the control of focus adjustment work and spherical aberration is not worked, focus on the additive operation that adds test signal shown in Figure 30 (a) on the focus drive signal that test signal generator 50 carries out 17 outputs of focus adjustment portion.Because the polarity of focus error signal maker 36 is in contrast to the polarity of focus drive signal, the output of focus error signal maker 36 becomes than the signal shown in Figure 30 (b) of the skew of signal phase shown in Figure 30 (a) 180 degree.At this state, the amplitude of spherical aberration signal is directly proportional in focus error signal, and therefore, spherical aberration signal becomes the waveform shown in Figure 30 (e).But shown in Figure 50 (a), the polarity of spherical aberration signal is opposite with the FE signal.

Spherical aberration is corrected study portion 52 by the gradually change COEFFICIENT K of spherical aberration rectification portion 132 of microcomputer 8 on one side, measure the amplitude of spherical aberration signal correct after on one side.Coefficient at time t1 is Kb, and the coefficient of time t2 is Kc.In addition, measure the amplitude of the spherical aberration signal after correcting by first amplitude detector 51.Among Figure 30, be Ka at coefficient; During Kc, the signal of the spherical aberration signal after the rectification does not become minimum, and when coefficient was Kb, this amplitude became minimum.Therefore, shown in Figure 30 (g), at the state of magnification Kb, the amplitude of the spherical aberration signal after the rectification becomes minimum, is decided to be the magnification K of spherical aberration rectification portion 132.

In conjunction with the work of the flowchart text of Figure 31 for the magnification K that determines spherical aberration rectification portion 132.At first, spherical aberration is corrected study portion 52 in step S1, and setting initial value Ka by microcomputer 8 is the magnification of spherical aberration rectification portion 132.In step S2, focus on test signal generator 50 when focus adjustment work and spherical aberration control are not worked, add the additive operation of testing signal on the focus drive signal of beginning focus adjustment portion 17.In step S3, obtain the amplitude of the spherical aberration signal of being corrected by spherical aberration rectification portion 132 from first amplitude detector 51, preserve as the amplitude minimum value.In step S4, the magnification of spherical aberration rectification portion 132 is reduced setting.

In step S5, utilize first amplitude detector 51 relatively: whether the spherical aberration signal amplitude after the rectification that is detected is also littler than in store amplitude minimum value.When the in store amplitude minimum value of the spherical aberration signal amplitude ratio after the rectification was also little, then in step S6, the spherical aberration signal amplitude after the rectification saved as the amplitude minimum value again as minimum value, enters into step S7.When the spherical aberration signal amplitude after correcting is not less than in store amplitude minimum value, enter into step S7.In step S7, relatively whether the magnification of spherical aberration rectification portion 132 is also bigger than Kc, if when big, gets back to step S4, if when little, enters into step S8.In step S8, setting spherical aberration rectification portion 132 corresponding to the magnification that is saved the amplitude minimum value, end process.

The following describes: 20 information faces of the CD with a plurality of information faces of rhythmo structure are write down or when regenerating the situation of replacing the spherical aberration rectification 132 magnification K of portion by each layer.

The recording/reproducing of CD 20 shown in Figure 5 is described.In the two-layer dish, if the information faces difference, then in conjunction with Figure 49; Defocusing the influence of spherical aberration signal that Figure 50 is illustrated is also different.In conjunction with Figure 51; The oscillogram explanation this point of Figure 52.

Figure 51 (a) expression is write down information faces L0 or the appearance of being cut apart by first shadow shield, 48 second shadow shields 49 when regenerating.Figure 51 (b) is expression outer Monday of a side focus error signal, and Figure 51 (c) is expression interior Monday of a side focus error signal, and Figure 51 (d) is the expression focus error signal, and Figure 51 (e) is the expression spherical aberration signal.The longitudinal axis is represented each voltage of signals, and transverse axis is represented to defocus.

Figure 52 (a) is that expression focuses on the appearance of being cut apart by first shadow shield 48 and second shadow shield 49 when being positioned at information faces L1.Figure 51 (b) is expression outer Monday of a side focus error signal, and Figure 51 (c) is expression interior Monday of a side focus error signal, and Figure 51 (d) is the expression focus error signal, and Figure 51 (e) is the expression spherical aberration signal.The longitudinal axis is represented each voltage of signals, and transverse axis is represented to defocus.

Shown in Figure 51 (a), suppose: be designed to focus when being positioned at information faces L0, the light beam of accepting light is segmented on 50% position of the beam radius of accepting light.Therefore, Figure 51 (b); (c); (d); (e) the illustrated waveform of waveform and Figure 49 is identical.

On the other hand, shown in Figure 52 (b), when focus was positioned at information faces L1, the interval when spherical aberration correcting lens 15 interval W are positioned at information faces L0 than focus narrowed down, and the light beam that is injected into object lens 1 becomes dispersed light.Therefore, information faces reflection and diminish by the light echo radius that being injected into of spherical aberration correcting lens 15 connects light accepting part.Such as, even first shadow shield 48; The adjustment amount of second shadow shield 49 is identical, and the radius of light beam still diminishes, and therefore, actual split position is also bigger than 50% above-mentioned radius.Be 75% among the figure.Thus, outer Monday side light amount ratio in Monday the sidelight amount few, therefore, Figure 52 (b) outer Monday side focus error signal amplitude less than Figure 52 (c) interior Monday the side focus error signal amplitude.

Its result, owing to defocus, outer Monday the side focus error signal with interior Monday the side focus error signal difference Figure 53 (e) spherical aberration signal with respect to outer Monday the side focus error signal and interior Monday side focus error signal sum the polarity opposite (phase place slow 180 to the FE signal is spent) of focus error signal of Figure 53 (d).As mentioned above, if the information faces difference of record or regeneration then along with the influence for spherical aberration detector 31 spherical aberration signal that object lens 1 move is also different, therefore, is necessary to change: the magnification of getting rid of the spherical aberration rectification portion 132 of this influence.

The replacement of the magnification of the spherical aberration rectification portion when illustrating that in conjunction with Figure 32 interlayer in the laminated optical disc moves.Light beam spot between Figure 32 (a) presentation layer when mobile moves.The magnification of Figure 32 (b) expression spherical aberration signal rectification portion.The longitudinal axis is represented each voltage of signals, the transverse axis express time.Figure 32 (c) is the conducting/disconnection (ON/OFF) of expression spherical aberration control, and Figure 32 (d) is the conducting/disconnection of expression focus adjustment.The longitudinal axis is the conducting/disconnection of control, and H disconnects the transverse axis express time for expression conducting, L for expression.Figure 32 (e) expression FE signal, Figure 32 (f) represents focus drive signal.The longitudinal axis is represented each voltage of signals, the transverse axis express time.

Laminated optical disc of the present invention comprises: the additive operation gain preservation portion that is used for not preserving by layer the magnification of spherical aberration rectification portion 132; Take out the magnification of desired spherical aberration rectification portion 132 and reset additive operation gain replacement portion and microcomputer 8 from gain preservation portion.At first, suppose the random track of beam flying, then, the work of regeneration L1 data is described at L0.At first, microcomputer 8 is preserved the magnification of L0 with spherical aberration rectification portion 132 in additive operation gain preservation portion, and focus adjustment and spherical aberration control is not worked promptly stop (a).

Then, the acceleration and deceleration driving pulse instruction of stipulating to focalizer driving circuit 9.Move to after the L1, originally idle focus adjustment becomes (the time b) at once after the conducting, makes spherical aberration control become conducting.Yet, if the unstable rule spherical aberration control of focus adjustment is also unstable.Therefore, Yi Bian observe the FE signal,, utilize additive operation gain replacement portion to replace the magnification (time c) of spherical aberration rectification portion 132 if FE signal pack judges then that in the scope of regulation focus adjustment is stable.Then, can become conducting (time d) to original idle spherical aberration control.Like this, there is no need by layer other; Move the spherical aberration signal influence of the different amount of movements that relearn object lens 1 to spherical aberration detector 31 by interlayer each time, can be at a high speed and high precision get rid of influence, its effect is big.

In addition, getting rid of adjustment of focusing system gives after the influence of spherical aberration signal, when focus adjustment and spherical aberration Control work, carry out the focus adjustment portion 17 or the adjustment of the gain of spherical aberration control part 135, can adjust because focus adjustment and spherical aberration are controlled the gain characteristic of the skew of disturbing, more the high precision adjustment also becomes possibility.In addition, the adjustment of gain compensation can utilize the additive operation of testing signal as adding on the control system; Quadrature phase homodyne detection method is carried out.

" embodiment 7 "

Figure 33 is the block diagram of expression embodiment 7 CD device structure.Figure 34 is the oscillogram in order to illustrate that the FE signal is corrected of present embodiment 7.The parts that are same as prior art, embodiment 6 among these figure are attached with identical symbol with part, omit its explanation.

Also same in the present embodiment with embodiment 6, according to outer Monday the side focus error signal and interior Monday side focus error signal sum focus error signal carry out focus adjustment; By outer Monday the side focus error signal and interior Monday the side focus error signal difference generate spherical aberration signal.

After the output signal of FE signal rectification portion 30 processing beam extender driving circuits 133, be added in the additive operation of FE signal.FE signal rectification portion 30 has the wave filter (below be designated as " wave filter of equal value ") and the bandpass filter of correcting regulator 34 identical characteristics with spherical aberration.These two wave filters are connected in series, and the output of wave filter is doubled to export after the setting.The frequency band that passes through of bandpass filter is configured to be higher than the adjustment of focusing system frequency band, and is lower than spherical aberration control system frequency band.In addition, in embodiment 7, the frequency band of adjustment of focusing system is lower than the frequency band of spherical aberration control system.Therefore, be included in the frequency band that is higher than adjustment of focusing system that the spherical aberration correcting lens changes at interval and be lower than after the frequency content multiplying gauge definite value multiple of spherical aberration control system frequency band, be added in the additive operation of FE signal.The influence that the spherical aberration control system is given adjustment of focusing system describes.

Spherical aberration correct amount in the spherical aberration control system promptly is added in adjustment of focusing system corresponding to spherical aberration correcting lens external disturbance at interval.This external disturbance is to change the interference that object lens arrive the distance till focusing on.

Describe in detail owing to spherical aberration correcting lens 15 variation at interval in conjunction with Figure 53, object lens arrive the situation of the variable in distance till focusing on.Figure 53 is the mode chart that the spherical aberration correcting lens gives object lens influence of distance till focus at interval.

Figure 53 (a) is that the expression optical disc surface arrives the thickness of information faces for best; The state of spherical aberration does not take place on the information faces.Equally, Figure 53 (b) is the thick situation of expression thickness.In addition, adjustment of focusing system operate as normal and utilize spherical aberration correcting lens 15 to correct the state of the spherical aberration that is taken place on the information faces.Figure 53 (c) is the situation of expression thin thickness.And the situation of Figure 53 (b) is same, and expression utilizes spherical aberration correcting lens 15 to correct the state of the spherical aberration that is taken place on the information faces.

Shown in Figure 53 (b), because matrix part thickness thickening, the interval W of spherical aberration correcting lens 15 narrows down.In addition, object lens 1 become far away to what focus on apart from Z.In addition, shown in Figure 53 (c), if the matrix part attenuation, then W broadens at interval; Become near apart from Z.Because the variation of the interval W of spherical aberration correcting lens 15 is changing apart from Z.That is, this variation apart from Z is that external disturbance as adjustment of focusing system works.

Like this, corresponding to the interval of spherical aberration correcting lens, object lens till focus on apart from earthquake, so this external disturbance is the thing that contacts same nature with the face of CD 20.Therefore, adjustment of focusing system will chase after from this external disturbance.Yet the frequency content that is higher than the adjustment of focusing system frequency band of this external disturbance flow into focalizer 2, can only improve the temperature of focalizer 2, can not chase after from.

Therefore, in FE signal rectification portion 30, be included in spherical aberration correcting lens being higher than the adjustment of focusing system frequency band and being lower than the multiplying of multiply by coefficient L on the frequency content of spherical aberration control system frequency band in changing at interval, afterwards, be added in the additive operation of FE signal, thus, the influence of spherical aberration correct amount to the FE signal followed in eliminating.Like this, can get rid of the uneven influence of disc substrate component thickness that is higher than the adjustment of focusing system frequency band, can reduce the focalizer heating and become possibility from adjustment of focusing system.

Virtual value test section 54 and FE correct the branch that study portion 55 is the above-mentioned coefficient L of decision.Virtual value test section 54 is included in the frequency content of the FE signal after the rectification and detects the virtual value that is higher than the adjustment of focusing system frequency band and is lower than spherical aberration control system band component, and output.It is that the output of learning virtual value test section 54 becomes minimum coefficient L that FE corrects study portion 55.Then, microcomputer 8 is set in coefficient L in the FE signal rectification portion 30.

Below, describe FE signal rectification portion 30 in detail in conjunction with Figure 35.Figure 35 is FE signal rectification portion 30 block diagrams.Input adapter 900 is connected the output of optical beam expander driving circuit 133.Second input adapter 904 is that FE corrects the output signal of study portion 55 by microcomputer 8 connections.The signal of being exported from out splice going splice 905 is on the FE signal that is added in as the output of focus error signal maker 36.

Input is sent to wave filter 901 of equal value at the signal of input adapter 900.Wave filter 901 of equal value has the wave filter of spherical aberration rectification regulator 34 identical characteristics as mentioned above.The output of wave filter 901 of equal value just is sent to bandpass filter 902.Following bandpass filter note is made BPF.The frequency band that passes through of BPF902 is higher than the frequency range that above-mentioned adjustment of focusing system frequency band is lower than spherical aberration control system frequency band.The output of BPF902 is sent to multiplicative operator 903.The signal of multiplicative operator 903 multiplying joint a and joint b, and export by joint c.Joint c is sent to out splice going splice 905.Joint b is connected second input adapter 904.

Because connect the output of optical beam expander driving circuit 133 on input adapter 900, the interval of spherical aberration correcting lens is just represented in the output of wave filter 901 of equal value.Extract be included in that this spherical aberration correcting lens changes at interval be higher than the adjustment of focusing system frequency band and be lower than the frequency content of spherical aberration control system frequency band among the BPF902 out.The multiplying of the setting L that signal of extracting out in the multiplicative operator 903 and FE rectification study portion 55 set, and by out splice going splice 905 outputs.

In conjunction with Figure 34 this work is described.In addition, setting make matrix part thickness inhomogeneous changes being higher than the adjustment of focusing system frequency band and being lower than in the frequency range of spherical aberration control system frequency band.Figure 34 (a) expression matrix part is in uneven thickness.The output of Figure 34 (b) expression optical beam expander driving circuit 133, the output of Figure 34 (c) expression wave filter 901 of equal value, the output of Figure 34 (d) expression PF902, the output of Figure 34 (e) expression FE signal rectification portion 30, the output of Figure 34 (f) expression focus error signal maker 36, the FE signal after Figure 34 (g) expression is corrected.The longitudinal axis of Figure 34 (b) is represented electric current, and the longitudinal axis of other oscillograms is represented each voltage of signals, the transverse axis express time.

Has the waveform shown in Figure 34 (b) in order to chase after shown in Figure 34 (a) from the optical beam expander drive current of matrix part thickness variation.In addition, spherical aberration is corrected regulator 34 drive currents and the correcting lens spaced relationship has the secondary vibration elements characteristic.Therefore, in being higher than the high frequency of each fixed frequency, become the relation of slow 180 degree of phase place at interval with respect to the correcting lens of drive current.Between the waveform of Figure 34 (a) and the waveform of Figure 34 (b) mutually the reason of phasic difference 180 degree be this.If the optical beam expander drive current shown in Figure 34 (b) is input to the wave filter of equal value 901 of Figure 35, its waveform becomes the waveform of Figure 34 (c).Because the frequency content of matrix part thickness variation is lower than the frequency band of spherical aberration control system, because above-mentioned reason, phase place is consistent between the waveform of Figure 34 (a) and the waveform of Figure 34 (c).

Because the frequency content of matrix part thickness variation is exactly the frequency band that passes through of BPF902, so the output of BPF902 has the waveform shown in Figure 34 (d) identical with wave filter 901 outputs of equal value.The output of FE signal rectification portion 30 has the waveform of the Figure 34 (e) that doubles BPF902 and be output as the setting multiple.

Because the frequency content of matrix part thickness variation is higher than the adjustment of focusing system frequency band, so adjustment of focusing system can not chase after the above-mentioned external disturbance that is produced from by spherical aberration correcting lens interval variation.Therefore, the FE signal becomes the waveform shown in 34 (f).Utilize FE to correct the method that study portion 55 adjusts the setting L that is set in second input adapter, the output amplitude of FE signal rectification portion 30 is adjusted, and the FE signal after the rectification becomes the waveform of the eliminating AC composition shown in Figure 34 (g).Therefore, the drive current of the matrix part thickness variation shown in Figure 34 (a) can not flow to focalizer driving circuit 9.

In addition, spherical aberration control off position, spherical aberration correcting lens 15 is stopped, not to the influence of FE signal.Therefore, stop to be added in the additive operation of FE signal by the specified multiple spherical aberration signal of signal rectification portion 30.Thus, stable focus adjustment becomes possibility.

Below, the determining method of above-mentioned coefficient L is described.In order to obtain coefficient L, need the in uneven thickness of regulation.That is, need be higher than the frequency of adjustment of focusing system frequency band and be lower than frequency variation in uneven thickness of spherical aberration control system frequency band.Yet, do not expect always to have so in uneven thickness in the actual CD.Therefore, to be higher than the adjustment of focusing system frequency band and to be lower than the method that the frequency of spherical aberration control system frequency band changes, can accomplish and exist the state of the state equivalent in uneven thickness of regulation to the interval of spherical aberration correcting lens.

Below, the state when the spherical aberration correcting lens being changed with the frequency that is higher than the adjustment of focusing system frequency band and is lower than spherical aberration control system frequency band at interval in conjunction with Figure 54 explanation.Figure 54 is the mode chart that spherical aberration correcting lens position gives object lens influence of distance till focus on, and the thickness of disc substrate parts is unified to remove certain a bit among Figure 54 (a)～(c), Figure 53 identical situation illustrated with the front.

Figure 54 (a) is the state that spherical aberration does not take place on thickness the best from the optical disc surface to the information faces of expression and the information faces.Equally, Figure 54 (b) is the optimum condition of the original matrix part thickness of expression when thick.In addition, spherical aberration correcting lens 15 comes work with the frequency content that is higher than the focus adjustment frequency band, adjustment of focusing system normally do not chase after from and do not correct the state of the spherical aberration that information faces takes place.Optimum condition during the original matrix part thin thickness of Figure 54 (c) expression.And Figure 54 (b) is same, and the state of the spherical aberration that takes place on the information faces is not corrected in expression.Same with Figure 53, shown in Figure 54 (b), the interval W of spherical aberration correcting lens 15 narrows down and object lens 1 becoming far apart from Z to focusing.In addition, shown in Figure 54 (c), when W broadens at interval, become near apart from Z.

Because the interval W of spherical aberration correcting lens 15 changes, changing apart from Z.That is, this variation apart from Z is that external disturbance as adjustment of focusing system works.Z to spherical aberration correcting lens 15 at interval the ratio of the variation of W almost with the ratio of the variation of W is identical at interval to spherical aberration correcting lens 15 in conjunction with the illustrated Z of Figure 53.

In addition, spherical aberration correcting lens 15 is to be higher than the frequency content work of focus adjustment frequency band; Adjustment of focusing system can not normally chase after from and the state of not correcting the spherical aberration that information faces takes place be, under the state that stops the work of spherical aberration control system, with the frequency that is higher than the adjustment of focusing system frequency band and be lower than the method that spherical aberration control system frequency band changes the interval of spherical aberration correcting lens and realize.

Therefore, be higher than the frequency of adjustment of focusing system frequency band and be lower than the method that spherical aberration control system frequency band changes the interval of spherical aberration correcting lens, can change into: and the state of the state equivalent in uneven thickness of existence regulation.Waveform in conjunction with Figure 36 illustrates its work.The output of Figure 36 (a) expression optical beam expander driving circuit 133.Equally, the output of the PF902 of Figure 36 (b) expression FE signal rectification portion 30, Figure 36 (c) expression FE corrects study portion 55 and exports to the coefficient L of FE signal rectification portion 30, the output of Figure 36 (d) expression FE signal rectification portion 30, Figure 36 (e) expression is as the FE signal of the output of focus error signal maker 36, FE signal after Figure 36 (f) expression is corrected, the output of Figure 36 (g) expression virtual value test section 54.The longitudinal axis of Figure 36 (b) is represented electric current, and the longitudinal axis of other oscillograms is represented each voltage of signals, the transverse axis express time.

In addition, when the study of setting L, spherical aberration is controlled at and stops, and the optical beam expander drive signal is followed the output of spherical aberration test signal generator 53 and exported, and its frequency band is identical with the waveform shown in Figure 34 (a).The output signal that is spherical aberration test signal generator 53 is to change in frequency that is higher than the adjustment of focusing system frequency band and the frequency that is lower than spherical aberration control system frequency band.FE corrects study portion 55 at the initial value time t0, as the coefficient L setting La of FE signal rectification portion 30.

At this moment, spherical aberration is controlled at and stops, and optical beam expander driving circuit 133 is followed the output signal of spherical aberration test signal generator 53, and therefore, the optical beam expander drive current becomes the waveform shown in Figure 34 (a).Therefore, the output of the BPF902 of FE signal rectification portion 30 becomes the waveform shown in Figure 34 (b).The output of FE signal rectification portion 30 becomes the waveform that Figure 34 (b) multiply by coefficient La.Because the FE signal phase of Figure 34 (e) FE signal phase and Figure 34 (d) differs 180 degree, shown in Figure 34 (f), the FE signal after the rectification becomes the big signal of amplitude.At this state, 54 outputs of virtual value test section become the Ea shown in Figure 34 (g).

FE corrects study portion 55 and changes the coefficient L of FE signal rectification portion 30 gradually by microcomputer 8, and measures the level of virtual value test section 54.Coefficient at time t1 is Lb, is Lc at the coefficient of time t2.Among Figure 36, coefficient is La; During Lc, the level of measuring virtual value test section 54 can not become minimum, when coefficient is Lb, becomes minimum.

Thereby shown in Figure 34 (g), at the time t1 that sets coefficient Lb, the output level of virtual value test section 54 becomes minimum.That is, the FE signal amplitude after the rectification becomes minimum at the state of coefficient Lb.Therefore, FE corrects study portion 55 and sets Lb as the optimum coefficient of FE signal rectification portion 30.In addition, this coefficient Lb is as Figure 53; Figure 54 is illustrated, because spherical aberration control when spherical aberration correcting lens 15 is actual mobile with respect to matrix part thickness, also plays a part same.

In conjunction with the flowchart text of Figure 37, the work of the coefficient L of decision FE signal rectification portion 30.At first, in step S1, FE corrects study portion 55 by microcomputer, the coefficient settings initial value La as FE signal rectification portion 30.In step S2, when focus adjustment work and spherical aberration were not worked, spherical aberration test signal generator 53 began to carry out to add the additive operation of testing signal on the optical beam expander drive signal of spherical aberration control part 135.In step S3,, preserve as the minimum value of virtual value from the virtual value of virtual value test section 54 acquisitions by the FE signal of FE signal rectification portion 30 rectifications.In step S4, the coefficient L of FE signal rectification portion 30 is reduced setting.

In step S5, whether also little than in store virtual value minimum value by the virtual value of the FE signal after the more detected rectification of virtual value test section 54.If the virtual value of the FE signal after the rectification is also littler than in store virtual value minimum value, then in step S6, the minimum value that the virtual value of the FE signal after the rectification is preserved virtual value again as minimum value, the processing that enters step S7.If the virtual value of the FE signal after correcting is not less than in store virtual value minimum value, the processing that then enters step S7.In step S7, relatively whether the coefficient L of FE signal rectification portion 30 is bigger than Lc, if when big, gets back to step S4, if when little, enters step S8.In step S8, set coefficient L, end process corresponding to the FE signal rectification portion 30 that is saved the virtual value minimum value.

In addition, when the control of focus adjustment and spherical aberration is not worked, carry out the method for the gain compensation adjustment of focus adjustment portion 17 or spherical aberration control part 135, can adjust because focus adjustment and spherical aberration are controlled the gain characteristic part of disturbing, more high-precision adjustment becomes possibility.

" embodiment 8 "

Figure 38 is the block diagram of the expression embodiment of the invention 8 CD device structure.Figure 39 is in order to illustrate spherical aberration and to focus on the eccentric performance plot of beating.The parts that are same as prior art, embodiment 6 among these figure are attached with identical symbol with part, omit its explanation.In addition, same with embodiment 6, according to outer Monday the side focus error signal and interior Monday side focus error signal sum focus error signal carry out focus adjustment, by outer Monday the side focus error signal and interior Monday the side focus error signal the signal of difference generate spherical aberration signal.

Hi-pass filter portion 56 takes out the above AC composition of the gyro frequency that is higher than disc motor 10 that is included in the spherical aberration signal.

Exist in the CD 20 local in uneven thickness, the high frequency spherical aberration when these will occurrence record regeneration.Therefore, when the frequency band of spherical aberration control system is DC, because local in uneven thickness remaining spherical aberration.By this spherical aberration, as worsening the distortion of regenerated signal.

The present invention is the method that changes the target location of adjustment of focusing system, in other words, with the method that deliberately defocuses, the influence of the remaining spherical aberration of reduction regenerated signal distortion deterioration etc.Virtual value is the influence of the little spherical aberration of 20m λ rms degree, can utilize 0.1 defocusing of μ m degree to lower.When the control frequency band of adjustment of focusing system is higher than the control frequency band of spherical aberration control system, can lower the spherical aberration control system can not chase after from the influence of high frequency spherical aberration.

The rectification of spherical aberration at first, is described in conjunction with Figure 38.Microcomputer 8 outputs to optical beam expander driving circuit 133 to the drive signal of setting.Optical beam expander driving circuit 133 utilizes spherical aberration to correct the method that regulator 34 comes drive ball surface aberration correcting lens 15 according to drive signal, corrects the DC composition of the spherical aberration of the light beam spot that is formed on CD 20 information faces.

Hi-pass filter portion 56 extracts the radio-frequency component as the spherical aberration detection signal of spherical aberration detector 31 outputs out.The signal of extracting out is doubled after M times, be added in additive operation as the FE signal of focus error signal maker 36 outputs.The composition of extracting out is the frequency that is higher than the control frequency band of spherical aberration control system.In the present embodiment because the spherical aberration control system as DC, so Hi-pass filter portion 56 is got rid of after the DC compositions, export.

In the AC frequency band, the target location of adjustment of focusing system is to change according to the spherical aberration detection signal.Be to defocus in the adjustment of focusing system.

In conjunction with Figure 39 residual spherical aberration is described; Defocus universal relation with distortion.The y axle of Figure 39 is represented to defocus, and the x axle is represented spherical aberration, and level line is represented distortion.The most inboard level line is represented distortion j1.Along with outside level line is represented distortion j2 successively; Distortion j3; Distortion j4; Distortion j5.And become the relation of j1＜j2＜j3＜j4＜j5.

Suppose defocus be 0, spherical aberration is 0 state, promptly the information reading performance of CD 20 is best on an A.That is, the distortion of expression reading performance becomes minimum value j0., during rotating a circle in the actual CD 20, there be the in uneven thickness of high frequency, therefore, follow the spherical aberration of its high frequency.The spherical aberration that is taken place is made as s1, s2.Thereby, between a α and some β spherical aberration takes place and the distortion deterioration.In addition: be made as s2, be made as s1 in the spherical aberration of a β in the spherical aberration of a α.Distortion changes in j0 and j2 scope.Yet, if changing, corresponding spherical aberration defocuses, distortion changes in j0 and j1 scope.That is, if the defocusing to f1, be f2 defocusing of a β an of α, then, distortion becomes j1.Thereby, generate the method that defocuses according to spherical aberration, can improve the deterioration of distortion.Thereby the coefficient M of above-mentioned Hi-pass filter portion 56 becomes following relational expression.

M＝(f2-f1)/(s2-s1)

In conjunction with Figure 40 explanation, to correct the antidote that residual spherical aberration influences by defocusing.Figure 40 is that the state owing to the spherical aberration of matrix part DC composition in uneven thickness has been corrected in expression.Figure 40 (a) waveform represents that matrix part is in uneven thickness.The output of Figure 40 (b) expression photosphere surface aberration detecting device 31.The output of Figure 40 (c) expression Hi-pass filter 56, the output of Figure 40 (d) expression focus error signal maker 36.The longitudinal axis is represented each voltage of signals, the transverse axis express time.

Shown in Figure 40 (a), matrix part is in uneven thickness to have inhomogeneous and DC composition in uneven thickness of AC composition of the part of CD 20.The method that microcomputer 8 control spherical aberrations are corrected regulator 34, the spherical aberration of correcting the DC composition, therefore, the spherical aberration detection signal becomes the signal shown in the Figure 40 (b) that has only the AC composition.In addition, s1 and s2 are corresponding to s1 and the s2 of Figure 39.M amplifies doubly in Hi-pass filter portion 56 after this spherical aberration detection signal takes out the AC composition shown in Figure 40 (b).Thereby the output of Hi-pass filter portion 56 becomes Figure 40 (c).In addition, f1 and f2 are corresponding to f1 and the f2 of Figure 39.Control system is carried out work, so that make the signal of output signal for deducting from the FE signal of Hi-pass filter portion 56, makes the signal of subtraction become 0.Therefore, the FE signal becomes the waveform shown in Figure 40 (d).Thereby generation defocuses corresponding to spherical aberration, can reduce the deterioration of distortion.

" embodiment 9 "

Figure 41 is the block diagram of the CD device structure of the expression embodiment of the invention 9.The parts that are same as prior art, embodiment 6 among these figure are attached with identical symbol with part, omit its explanation.In addition, same with embodiment 6, according to outer Monday the side focus error signal and interior Monday side focus error signal sum focus error signal carry out focus adjustment, by outer Monday the side focus error signal and interior Monday the side focus error signal the signal of difference generate spherical aberration signal.

In the present embodiment, the position of control object lens 1 is so that become 0 as the FE signal of the output signal of focus error signal maker 36.In addition, the interval of control spherical aberration correcting lens 15 is so that become 0 as the spherical aberration detection signal of spherical aberration detector 31 outputs.The rectification branch that does not have illustrated spherical aberration detection signal according to the FE signal among the embodiment 6.

Linking frame Figure 43 illustrates interfering with each other of focus adjustment and spherical aberration control.Figure 43 is for the block diagram of present embodiment 9 control frequency bands and disturbing effect is described.The parts that are same as prior art, embodiment 6 among these figure are attached with identical symbol with part, omit its explanation.α 1 system representation spherical aberration control system is to the interference of adjustment of focusing system.α 1 is the ratio that optical beam expander motivation value and object lens is arrived the distance till focusing on.α 2 systems are the interference to the spherical aberration control system of expression focus adjustment.α 2 is the ratios to the error of the spherical aberration detection signal that defocuses.K1 is the detection sensitivity of focus error signal maker 36.K2 is the detection sensitivity of spherical aberration detector 31.

As described in embodiment 6, focus adjustment and spherical aberration control interfere with each other.Particularly, when defocus amount is f3, become K1 * α 2 * f3 corresponding to the detection error that defocuses.In addition, when the spherical aberration correct amount was b1, the distance change till object lens arrive and focus on was α 1 * b1, becomes the external disturbance of adjustment of focusing system.In embodiment 6, the formation of getting rid of the detection error of the spherical aberration detection signal that takes place corresponding to defocusing has been described, but, in the present embodiment, make the control frequency band of focus adjustment become ten times the method that the spherical aberration detection signal detects error, even the detection error corresponding to the spherical aberration detection signal that defocuses takes place, can realize the control of stable focus adjustment and spherical aberration.

Figure 42 A to Figure 42 D is for the 9 control frequency bands that present embodiment is described and the performance plot of disturbing effect.Figure 44 A to Figure 44 D is for the control part of present embodiment 9 is described; The performance plot of driving circuit and controller properties.Below, as an example, above-mentioned characteristic is described in conjunction with these figure.

At first, in conjunction with Figure 44 A to Figure 44 D explanation control part; The characteristic of driving circuit and regulator.Figure 44 A represents the characteristic till focus adjustment portion 17 arrives focalizer driving circuit 9.Figure 44 B represents the characteristic of focalizer 2.Figure 44 C represents the characteristic from spherical aberration control part 135 to optical beam expander driving circuit 133.Figure 44 D represents the characteristic of spherical aberration rectification regulator 34.The last figure expression gain characteristic of each figure, the longitudinal axis is gain, transverse axis is represented frequency.Figure below is represented phase propetry, and the longitudinal axis is represented phase place, and transverse axis is represented frequency.

Shown in Figure 44 A, carry out the phase compensation of focus adjustment in the focus adjustment portion 17, bring up to 45deg (degree) as the 2KHz phase place that focusing gain focuses on.Shown in Figure 44 B, the first resonance frequency of the 46Hz that has an appointment in the focalizer 2, the above frequency band of first resonance frequency is inclination-40dB/dec.Equally, shown in Figure 44 C, carry out the phase compensation of spherical aberration control in spherical aberration control part 135, the 300Hz phase place that gain focuses on as spherical aberration is brought up to 45deg's.Shown in Figure 44 D, spherical aberration is corrected the first resonance frequency of the 66Hz that has an appointment in the regulator 34, and the above frequency band of first resonance frequency is inclination-40dB/dec's.

Then, in conjunction with Figure 42 interfering with each other of focus adjustment and spherical aberration control is described.Figure 42 A represents that the control frequency band that focuses on is 2KHz; The frequency band of spherical aberration control is the open loop characteristic of the focusing of suffered disturbing effect among the 300Hz.Equally, Figure 42 B represents the open loop characteristic of spherical aberration control.Figure 42 C represents that the control frequency band that focuses on is 5KHz; The frequency band of spherical aberration control is the open loop characteristic of the focusing of suffered disturbing effect among the 300Hz.Equally, the open loop characteristic of Figure 42 D spherical aberration control.The last figure expression gain characteristic of each figure, the longitudinal axis is gain, transverse axis is represented frequency.Figure below is represented phase propetry, and the longitudinal axis is a phase place, and transverse axis is represented frequency.

Shown in Figure 42 A and 42C, the control frequency band that focuses on is brought up to 5KHz (Figure 42 C) from 2KHz (Figure 42 A), the control frequency band that spherical aberration is corrected leaves the method for 300Hz, can make the frequency band of performance disturbing effect be higher than the control frequency band that spherical aberration is corrected far away.Particularly, the gain of (Figure 42 B) performance improves and becomes 1.3KHz～11KHz scope in the scope about frequency 50Hz～4KHz.Shown in Figure 42 D, during the approaching control of gain raising scope frequency band, the gain raising rises near the 0dB, and therefore, small gain variations or external disturbance influence cause vibration easily., shown in Figure 42 D, gain raising scope is when the control frequency band is far away, and gain improves more much lower than 0dB, and therefore, control system is stable.In addition, the control frequency band that spherical aberration is corrected is when 300Hz reduces, and is same, the influence that can avoid disturbing from the control frequency band that focuses on.As mentioned above, the control frequency band of focus adjustment becomes the method more than 10 times of spherical aberration control frequency band, can reduce the influence of the interference of adjustment of focusing system and spherical aberration control system, can realize the control of stable focus adjustment and spherical aberration.

" embodiment 10 "

Figure 45 is the block diagram of the expression embodiment of the invention 10 CD device structure.When Figure 46 is the retrieval of embodiment 10 for the oscillogram of spherical aberration is described.Figure 47 is the process flow diagram of the spherical aberration rectification order of the radial direction of embodiment 10 when moving.The parts that are same as prior art, embodiment 6 among these figure are attached with identical symbol with part, omit its explanation.In addition, same with embodiment 6, according to outer Monday the side focus error signal and interior Monday side focus error signal sum focus error signal carry out focus adjustment, by outer Monday the side focus error signal and interior Monday the side focus error signal the signal of difference generate spherical aberration signal.

The spherical aberration detection signal as the output signal of spherical aberration detector 31 of Figure 45 is input to spherical aberration control part 135, carries out phase compensation by spherical aberration control part 135; The filtering operation of gain compensation etc. and generating: in order to carry out the spherical aberration correcting signal that spherical aberration is corrected.Spherical aberration control part 135 is exported to optical beam expander driving circuit 133: for the drive signal of moving sphere aberration correcting lens 15; Accept the spherical aberration of this drive signal and correct regulator 34 with regard to moving sphere aberration correcting lens 15.That is, spherical aberration is approximate to become 0, promptly as focus B, the focus C unanimity of the illustrated Fig. 2 of embodiment 6, just corrects control, makes focus B, focus C while approximated position A.

Trail-and-error signal generator 18 utilizes prime amplifier 11 output signals to generate: from shaven head 5 exported by the rub-out signal of relevant CD 20 radial directions between the light beam spot of light harvesting and the magnetic track 28.Trail-and-error signal generator 18 is according to input signal, and the detection mode that generally is called the trail-and-error of the method for recommending generates trail-and-error signal (to call the TE signal in the following text).TE signal as trail-and-error signal generator 18 output signals carries out phase compensation in tracking control section 19; After the filtering operation of gain compensation etc., output to tracking regulator driving circuit 26.

Drive object lens 1 by tracking regulator 27 according to the drive signal of tracking regulator driving circuit 26, make the magnetic track 28 of light beam spot scanning on CD 20 information faces 29, realize tracking Control.

Utilization is as the transport platform 60 of searching mechanism function, can move shaven head 5 on the radial direction of CD 20, and transport platform 60 to be output signals (drive signal) by transport platform driving circuit 62 drive.Yet, there are the following problems: focus adjustment and spherical aberration are controlled at work and tracking Control when not working, light beam spot is during across the magnetic track on the information faces 29, and the external disturbance that has with TE signal same frequency overlaps the FE signal, makes focus adjustment become instability.The present invention uses for reference the problems referred to above and carries out.

Therefore, the tracking Control off position stops spherical aberration control and makes the spherical aberration adjustment device leave the optimum position, produces spherical aberration.Owing to produce spherical aberration, it is big that the light beam spot on the information faces becomes.Therefore, the size of light beam spot is also bigger than the pitch of ditch, so the amplitude of TE signal diminishes.

In conjunction with Figure 48 this work is described.That in addition, sets matrix part in uneven thicknessly is being higher than the adjustment of focusing system frequency band and is being lower than the frequency variation of spherical aberration control system frequency band.The output of Figure 48 (a) expression trail-and-error signal generator 18.The output of Figure 48 (b) expression focus error signal maker 36, the output of Figure 48 (c) expression optical beam expander driving circuit 133.Figure 48 (c) longitudinal axis is represented electric current, and the longitudinal axis of other oscillograms is represented each voltage of signals, the transverse axis express time.In addition, time t1 is output the best of optical beam expander driving circuit 133 and the state that the spherical aberration of light beam spot does not take place on the information faces of CD 20 to time t2 interval.In addition, t2 is that the output of optical beam expander driving circuit 133 is left the optimum value ormal weight and the state of the spherical aberration of light beam spot is obviously taken place on the information faces of CD 20 to time t3 interval.

In the magnetic track of CD 20, core shift is arranged, so when tracking Control was not worked, across a plurality of magnetic tracks, the trail-and-error signal had the waveform of Figure 48 (a).Generate because focus error signal is non-some aberration method, during across magnetic track, influence when cross channel takes place, and become the waveform shown in Figure 48 (b) at light beam spot.

In addition, among Figure 48 (b), the focus error signal of the influence when solid line is represented to be subjected to cross channel, the focus error signal of the influence when dotted line is represented not to be subjected to cross channel.

In addition, among Figure 48 (c), time t1 is the best output that is illustrated in the spherical aberration that light beam spot does not take place on the information faces of CD 20 to time t2 interval, and time t2 is the output of leaving the optimum value ormal weight that the light beam spot spherical aberration obviously takes place on the expression information faces 29 to time t3 interval.

At time t1 in time t2 interval because the spherical aberration of light beam spot does not take place on the information faces, shown in Figure 48 (a), the amplitude maximum of trail-and-error signal., to time t3 interval the spherical aberration that light beam spot obviously takes place on the expression information faces 29 at time t2, the amplitude of trail-and-error signal diminishes.Equally, the influence the during cross channel that takes place in the focus error signal also becomes maximum at the time of the spherical aberration that light beam spot does not take place t1 in time t2 interval, and diminishes in time t3 interval at the time t2 that the spherical aberration of light beam spot obviously takes place.

Like this, when tracking Control is not worked, spherical aberration control is stopped and the spherical aberration correct amount leaves the method for optimum position ormal weight, focus adjustment is stablized in the influence in the time of can reducing the cross channel that shows in the focus error signal.In addition, because the external disturbance that influences can reduce cross channel the time can reduce the electric current that flows to focalizer 2, can avoid because the damage that super-high-current causes by focalizer 2 protection focalizer 2.

Be described in more detail this work in conjunction with Figure 46.Figure 46 (a) expression is with respect to the radial direction position of the light beam spot of time.Equally, the output of Figure 46 (b) expression spherical aberration detector 31, the output of Figure 46 (c) expression optical beam expander driving circuit 133.The duty of Figure 46 (d) expression tracking control section 19, the output of Figure 46 (e) expression transport platform driving circuit 62.The longitudinal axis is represented each voltage of signals, the transverse axis express time.

In the moving of radial direction in the retrieval, shown in Figure 46 (c), at first, at time a, spherical aberration control part 135 is according to the indication of microcomputer 8, stops output according to spherical aberration detector 31 outputs to optical beam expander driving circuit 133.Simultaneously, change the output valve of optical beam expander driving circuit 133, so that moving sphere aberration correcting lens 15, make spherical aberration approximate from 0 offset setting.Then, shown in Figure 46 (d), at time b, tracking control section 19 temporarily stops tracking Control according to the indication of microcomputer 8.

Then, shown in Figure 46 (e), till time c, to transport platform driving circuit 62 output transport platform drive signals.During from time b to time c this, transport platform driving circuit 62 makes the transport platform 60 that shaven head 5 is housed move at the radial direction of CD 20 according to the transport platform drive signal that microcomputer 8 transmits.Thus, shown in Figure 46 (a), light beam spot from interior Monday of CD outside the side direction Monday side shifting.Then, shown in Figure 46 (d), tracking control section 19 at time c, is restarted tracking Control according to the indication of microcomputer 8.At last, shown in Figure 46 (c), at time d, spherical aberration control part 135 is according to the indication of microcomputer 8, and 133 outputs of removing corresponding to spherical aberration detector 31 outputs to the optical beam expander driving circuit stop, and restart spherical aberration control.

Like this, when tracking Control is not worked, make spherical aberration correcting lens 15 skew settings, increase the method for the spherical aberration that takes place on the light beam spot, influence becomes possibility in the time of can reducing the cross channel that takes place on the FE signal.

Be described in more detail work in conjunction with the process flow diagram of Figure 47 on radial direction for light beam spot is moved.At first, in step S1,8 pairs of spherical aberration control parts of microcomputer 135 indication: when stopping spherical aberration control, make spherical aberration correcting lens 15 from present offset to setting.In step S2,8 pairs of tracking control section of microcomputer, 19 indications: temporarily stop tracking Control.In step S3,8 pairs of transport platform driving circuits of microcomputer, 62 output transport platform drive signals are so that light beam spot moves to the radius of target position.In step S4,8 pairs of tracking control section of microcomputer, 19 indications: restart tracking Control.In step S5,135 indications of 8 pairs of spherical aberration control parts of microcomputer: when getting back to the control position of step S1, restart spherical aberration control from the spherical aberration correcting lens 15 of control position skew setting, and end process.

Like this, when the retrieval of following radial direction to move, the influence in the time of can reducing the cross channel that takes place in the FE signal can realize that stable focus adjustment becomes possibility.

In the above embodiments, illustrated that to information recording surface be the optical disc apparatus that the CD of a layer or two layers writes reading of data in data or the such CD, still, the number of information recording surface is more than three layers, also is fine.

In addition, in the optical disc apparatus of the foregoing description 6 to embodiment 10, also can utilize in the CD of embodiment 1 employed stepping motor 35 and spherical aberration to correct regulator and come drive ball surface aberration correcting lens.Particularly, the information recording surface of CD is more than three layers the time, and additional stepping motor 35 is for more effective.

Utilize possibility on the industry

According to optical disc apparatus of the present invention, even the NA of the Wu mirror of illumination beam compares Yi on the Zai CD Wang NA big (on NA Wei 0.85 Yi), spherical aberration can suitably be corrected, can be real The record regenerating of the more highdensity data of Xian.

Claims (13)

1, a kind of optical disc apparatus carries out record/or regeneration to the information carrier of two information faces having lamination at least, comprising:

The light beam irradiates mechanism of illumination beam;

Pack mechanism to the above-mentioned light beam of above-mentioned information carrier pack;

Focalizer in order to change the pack position of above-mentioned light beam, moves above-mentioned pack mechanism on the almost vertical direction of information carrier information faces;

Accept optical mechanism, accept the reflected light from information carrier of above-mentioned light beam;

The pack state detection mechanism according to the above-mentioned signal of accepting optical mechanism, detects the signal corresponding to pack state of above-mentioned light beam on the information carrier information faces;

Focus adjustment mechanism according to the signal of above-mentioned pack state detection mechanism, drives above-mentioned focalizer, and control makes the want position of light beam pack in above-mentioned information carrier information faces;

Spherical aberration testing agency according to the above-mentioned optical mechanism signal of accepting, detects the signal corresponding to the amount of spherical aberration that takes place on the light beam pack position on the above-mentioned information carrier information faces;

The spherical aberration changeable mechanism by being driven by elastic body, changes the spherical aberration that the light beam of institute of above-mentioned pack mechanism pack is taken place on the pack position;

The spherical aberration control gear according to the described spherical aberration changeable mechanism of signal controlling of above-mentioned spherical aberration testing agency, makes that spherical aberration is approximate to become 0;

The skew applying mechanism applies skew to above-mentioned spherical aberration changeable mechanism;

Mechanism is replaced in skew, the side-play amount of replacing above-mentioned skew applying mechanism according to above-mentioned information carrier information faces.

2, optical disc apparatus according to claim 1 is characterized in that,

When the spherical aberration control gear is not worked, given skew is applied to the spherical aberration changeable mechanism by the skew applying mechanism; When the spherical aberration control gear is worked, on average decide skew and the skew of replacing the skew applying mechanism according to what the above-mentioned spherical aberration changeable mechanism in each week of information carrier drove output.

3, a kind of optical disc apparatus comprises:

The pack mechanism of light beam pack on information carrier;

Focalizer moves above-mentioned pack mechanism on the approximately perpendicular direction of information carrier information faces;

The spherical aberration changeable mechanism changes the spherical aberration that the light beam of institute of above-mentioned pack mechanism pack takes place on the pack position;

Make the driving mechanism of above-mentioned spherical aberration changeable mechanism work;

Accept optical mechanism, accept the reflected light from information carrier of above-mentioned light beam;

The pack state detection mechanism according to the above-mentioned optical mechanism signal of accepting, detects the signal corresponding to pack state of above-mentioned light beam on the information carrier information faces;

Focus adjustment mechanism according to the signal of above-mentioned pack state detection mechanism, drives above-mentioned focalizer, and control makes the want position of light beam pack in above-mentioned information carrier information faces;

Spherical aberration testing agency according to the above-mentioned signal of accepting optical mechanism, detects the signal corresponding to the amount of spherical aberration that takes place on the light beam pack position on the above-mentioned information carrier information faces;

The spherical aberration control gear, the signal according to above-mentioned spherical aberration testing agency drives above-mentioned driving mechanism, and control makes that spherical aberration is approximate to become 0; And

The spherical aberration straightening mechanism, gain is in accordance with regulations amplified after the signal of above-mentioned pack state detection mechanism, is added on the detection signal of above-mentioned spherical aberration testing agency.

4, optical disc apparatus according to claim 3 is characterized in that, comprising:

The first test signal generating mechanism applies test signal to above-mentioned focalizer;

The first amplitude detecting mechanism detects the detection signal amplitude of above-mentioned spherical aberration testing agency;

Spherical aberration is corrected learning organization, test signal is added in the state of above-mentioned focalizer by the above-mentioned first test signal generating mechanism, the additive operation of being obtained the spherical aberration signal straightening mechanism by the above-mentioned first amplitude detecting mechanism gains, so that spherical aberration detection signal amplitude minimum.

5, optical disc apparatus according to claim 4 is characterized in that, above-mentioned spherical aberration is corrected learning organization in the work of focus adjustment mechanism and above-mentioned spherical aberration control gear when not working carries out the study of additive operation gain.

6, optical disc apparatus according to claim 3 is characterized in that, above-mentioned spherical aberration signal straightening mechanism comprises:

Mechanism is preserved in additive operation gain, has the additive operation gain in the information monomer of rhythmo structure information carrier information faces by each layer preservation;

Mechanism is replaced in additive operation gain, preserves from above-mentioned additive operation gain and takes out corresponding to the additive operation gain of light-beam position the mechanism and replace.

7, optical disc apparatus according to claim 3 is characterized in that, comprising:

The first test signal generating mechanism applies test signal to above-mentioned focalizer;

Focus adjustment gain adjusting mechanism is adjusted the gain of focus adjustment mechanism;

The second test signal generating mechanism applies test signal to above-mentioned driving mechanism;

Spherical aberration ride gain adjusting mechanism is adjusted the gain of spherical aberration control gear;

When focus adjustment mechanism and the work of spherical aberration control gear, above-mentioned first test signal after first test signal that above-mentioned focus adjustment gain adjusting mechanism is taken place according to the above-mentioned first test signal generating mechanism and focus adjustment one are touring, adjust, and the above-mentioned spherical aberration test signal of above-mentioned spherical aberration ride gain adjusting mechanism after to be the spherical aberration test signal that taken place according to the above-mentioned second test signal generating mechanism and spherical aberration control one touring adjusted.

8, a kind of optical disc apparatus comprises:

Pack mechanism to information carrier pack light beam;

Focalizer moves above-mentioned pack mechanism on the almost vertical direction of information carrier information faces;

The spherical aberration changeable mechanism changes the spherical aberration that institute of above-mentioned pack mechanism pack light beam is taken place on the pack position;

Driving mechanism makes the work of above-mentioned spherical aberration changeable mechanism;

Accept optical mechanism, accept the reflected light from carrier of above-mentioned light beam;

The pack state detection mechanism according to the above-mentioned signal of accepting optical mechanism, detects the signal corresponding to pack state of above-mentioned light beam on the information carrier information faces;

Focus adjustment mechanism according to the signal of above-mentioned pack state detection mechanism, drives above-mentioned focalizer, and control makes the want position of above-mentioned light beam pack in above-mentioned information carrier information faces;

Spherical aberration testing agency according to the above-mentioned optical mechanism signal of accepting, detects the signal of the amount of spherical aberration that takes place corresponding to light beam pack position on the above-mentioned information carrier information faces;

The spherical aberration control gear, the signal according to above-mentioned spherical aberration testing agency drives above-mentioned driving mechanism, and control makes that spherical aberration is approximate to become 0; And

Pack state detection signal straightening mechanism amplifies by given gain after the signal of above-mentioned spherical aberration testing agency, is added on the detection signal of above-mentioned pack state detection mechanism.

9, optical disc apparatus according to claim 8 is characterized in that,

Comprise focus adjustment mechanism, when above-mentioned spherical aberration control gear is not worked, the detection signal that pack state detection signal straightening mechanism defined multiple is amplified above-mentioned spherical aberration testing agency is not added on the detection signal of pack state detection mechanism, and only according to the detection signal of above-mentioned pack state detection mechanism, drive above-mentioned focalizer, control makes the want position of light beam pack in above-mentioned information carrier information faces.

10, optical disc apparatus according to claim 8 is characterized in that, also comprises:

The second test signal generating mechanism applies test signal to above-mentioned driving mechanism;

The second amplitude detecting mechanism, the detection signal amplitude of detection pack state detection mechanism;

The pack state-detection is corrected learning organization, by the above-mentioned second test signal generating mechanism test signal is added in the state of above-mentioned driving mechanism, the virtual value of obtaining the pack state detection signal by the above-mentioned second amplitude detecting mechanism becomes the additive operation gain of minimum pack status detection signal straightening mechanism.

11, optical disc apparatus according to claim 10 is characterized in that, above-mentioned pack state-detection is corrected learning organization and under the idle state of above-mentioned spherical aberration control gear, carried out the study of additive operation gain in the work of focus adjustment mechanism.

12, optical disc apparatus according to claim 8, comprising:

The first test signal generating mechanism applies test signal to above-mentioned focalizer;

Focus adjustment gain adjusting mechanism is adjusted the gain of focus adjustment mechanism;

The second test signal generating mechanism applies test signal to above-mentioned driving mechanism;

Spherical aberration ride gain adjusting mechanism is adjusted the gain of spherical aberration control gear;

When making the work of focus adjustment mechanism and spherical aberration control gear, above-mentioned first test signal after first test signal that above-mentioned focus adjustment gain adjusting mechanism is taken place according to the above-mentioned first test signal generating mechanism and focus adjustment one are touring, and adjust, above-mentioned spherical aberration test signal after the spherical aberration test signal that above-mentioned spherical aberration ride gain adjusting mechanism is taken place according to the above-mentioned second test signal generating mechanism and spherical aberration control one are touring, and adjust.

13, a kind of optical disc apparatus comprises:

Pack mechanism to information carrier pack light beam;

Focalizer moves above-mentioned pack mechanism on the almost vertical direction of information carrier information faces;

The spherical aberration changeable mechanism changes the spherical aberration that institute of above-mentioned pack mechanism pack light beam takes place on the pack position;

Driving mechanism makes the work of above-mentioned spherical aberration changeable mechanism;

Accept optical mechanism, accept the reflected light of above-mentioned light beam heating from information carrier;

The pack state detection mechanism according to the above-mentioned optical mechanism signal of accepting, detects the signal corresponding to pack state of above-mentioned light beam on the information carrier information faces;

Focus adjustment mechanism according to the signal of above-mentioned pack state detection mechanism, drives above-mentioned focalizer, and control makes the want position of light beam pack in above-mentioned information carrier information faces;

Spherical aberration testing agency according to the above-mentioned signal of accepting optical mechanism, detects the signal corresponding to the amount of spherical aberration that takes place on the light beam pack position on the above-mentioned information carrier information faces; With

The spherical aberration control gear, the detection signal according to above-mentioned spherical aberration testing agency makes above-mentioned driving mechanism work, and control makes that spherical aberration is approximate to become 0;

Make frequency band ten times or more of the frequency band of above-mentioned focus adjustment mechanism at above-mentioned spherical aberration control gear.

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