CN1007295B - Optical scanning unit - Google Patents

Abstract

An optical scanning unit with an objective for the focussing a beam of radiation along an optical axis into a scanning spot on the surface of an information carrier. The scanning unit also has an electromagnetic drive for correcting the position of the objective with respect to the information carrier. The drive has an objective mount supported in an annular, moving magnetic member which is axially magnetized and is arranged coaxially about the optical axis. The drive is further provided with fixed coils which interact with the magnetic member via an air gap. The fixed coils are arranged along at least three radial planes which are normal to the optical axis. Two planes lie in the area of the axial ends of the centrally positioned magnetic member and the third central plane which extends between the two outer radial planes.

Description

Optical Scanning unit

The present invention relates to a kind of optical scanner, this device is used to control and the record track of beam alignment in information carrier surface to be scanned.This scanister has object lens, and object lens have an optical axis, and it is equipped with one and is used for light beam is focused into objective lens on the analyzing spot on above-mentioned surface.This scanister also has one to be used for revising continuously the electromagnetic actuator device of object lens with respect to the information carrier position, this drive unit is equipped with the objective carrier of installation object lens, the movable toroidal magnet that this objective carrier has a permanent magnetic material to make, this magnet and optic axis are coaxial and be equipped with magnetic pole, this drive unit also is equipped with fixing coil, this coil is positioned on the outer radial plane of two end regions of magnet axis of centralized positioning, and carries out magnetic action with above-mentioned magnet mutually by air-gap.

No. the 3234288th, Deutsche Bundespatent (PHD82,089, this patent draw be referenced patent) once reported this optical scanner.In this known scanister, object lens are fixed on the sleeve of movable a, axial permanent magneticization.Two ends are as magnetic pole.The coil of hard-wired drive unit is a sectional coil, and coil is divided into two groups, and every group has three or four coils, coil winding be placed in the sleeve two ends near.Each sectional coil is designed to have the pancake coil that two parts coil is formed, mutually coaxial and with the coaxial distribution of above-mentioned sleeve, when electric current flowing through coil part, the electric current in the sleeve coiler part far away with flow through near the current reversal in the coiler part of sleeve.Adopt this known coil arrangement method, can produce desired three kinds of power along three axles of quadrature coordinate system, and around two kinds of rotating torques of two axles of above-mentioned axes of coordinates.

Adopt the drive unit of this known scanister, can realize whole desired object lens motions on the principle.These motions comprise: direction is parallel to the axially-movable of objective lens optical axis, and this motion is used for that light beam is focused into luminous point and drops on the information sides of rotary CD; And two kinds of radial motions that are mutually the right angle and/or around two be mutually the right angle and with two kinds of banking motions of rectangular two axles of optical axis.The four kinds of motions in back are used for to radially following the tracks of with tangential luminous point track.

Yet, this known drive unit is imperfect, magnetic force between coil and the magnetosheath tube changes along with the axial displacement of object lens, like this, even object lens have only a very little axial displacement with respect to the center between two coil winding, drive unit just no longer has the ability of mobile object lens on request, does not so just reach the requirement of focused beam and the requirement that the luminous point track is followed the tracks of.In fact, for realizing accurately moving along optic axis, the coil winding separation far suits a bit, but, the possibility that produces above-mentioned other direction motions can promptly reduce therefrom, even so that object lens are very little apart from the distance of center, can guarantee no longer that also the track of luminous point is followed the tracks of by the suitable driving of object lens.

The objective of the invention is to invent a kind of optical scanner in type described in the preamble, this device assembles coil in such a way, make when the object lens mobile phase when far away apart from the time, power that focus movement is required and required the trying hard to keep of track tracking are held constant or constant substantially.

Optical scanner of the present invention has another characteristic: promptly can also arrange more coil at least one sagittal plane, center between the above-mentioned outer radial plane.

In this optical scanner, when object lens moved distant apart from the time, power that focus movement is required and track are followed the tracks of required trying hard to keep and are held constant or constant substantially.

In preferred embodiments, at least three sectional coils all are arranged in the outerplanar in all cases, and magnet is equipped with magnetic pole on its two ends.The characteristics of this embodiment are: in sagittal plane, a center, have at least three sectional coils at least, each sectional coil comprises active coiler part facing to magnet (it distributes along the peripheral direction of magnet) and away from the coiler part of magnet.Look that from the peripheral direction of magnet sectional coil adjoins each other.

Above-mentioned coil arrangement mode of the present invention make might utilize coil in the central plane make object lens with the rectangular direction of optical axis on move, can also utilize two coils in sagittal plane, the outside that object lens are moved along the objective lens optical axis direction, if necessary, the latter's coil also can be used for making object lens around tilting with the rectangular axle of optical axis.Employing can realize above-mentioned these possibilities with the magnet of simple method axial magnetized.

The advantage of scanister of the present invention is: after coil is energized, when object lens moved one section be enough to focal spot and keep luminous point focus on the information sides of CD apart from the time, axial force and radial force that coil is applied on the magnet at least almost remain unchanged.Other advantage is: the good coil arrangement mode of the present invention makes can become the coil design of fringe region the flat coil, this means that the structure height of scanister and the axial dimension of magnet axial size and objective carrier can do very for a short time.So just at an easy rate the center of gravity of objective carrier is on the center of gravity of objective lens.Resulting like this another advantage is: when the coil in zone, center was energized, radial force was applied on the objective carrier that has object lens, can not produce uncontrollable moment, and this moment can cause object lens inclining, caused driving imbalance therefrom.

Sectional coil in sagittal plane, the outside is mainly used in moving axially of object lens.But, by selection excitation to sagittal plane, outside sectional coil, also may be because the inclination of magnet apply moment on magnet, like this, object lens can be around slightly rotatablely moving with the rectangular axle of optical axis.When selective excitation, the sectional coil in the sagittal plane, center is at mobile object lens in the radial direction.This means in this embodiment only have the coil in the outer radial plane to be used for light beam is focused into luminous point, if necessary, the coil in the central plane aims at object lens, to follow the tracks of the record track of CD to be scanned together with the coil in the outerplanar.

For object lens are produced constant axial lifting force, between the sectional coil on two outer radial planes of requirement composition coil winding a minor increment of determining is arranged.A kind of possible embodiment is arranged, the gap of leaving between above-mentioned sectional coil winding is used economically.The characteristics of this scheme are: the axial dimension of sectional coil is greater than the axial dimension of sectional coil in the fringe region in the sagittal plane, center.

Adopt this coil arrangement method, can make that object lens can fast moving big and be that constant axial force and radial force is applied on the object lens.Have another advantage like this: the most of coil in the sagittal plane, center provides the possibility of more adjustment and calibration, the sensitivity of the servo-drive system that can improve in the scanister like this to be adopted.

In another preferred version, magnet is equipped with magnetic pole at its two ends, be characterized in: the coil in above-mentioned each sagittal plane is a toroid winding, these coils are around above-mentioned magnet co-axial alignment, and have at least three sectional coils to be arranged in the sagittal plane, center, when the peripheral direction at magnet looked, these sectional coils adjoined mutually.

The advantage that this preferred embodiment had is: because toroid winding only is used for making the object lens axially-movable to reach the focusing purpose, so can realize moving axially very efficiently, this is because toroid winding can be in the effective coverage of magnets magnetic fields fully.

Because toroid winding can not be applied to any torque on the magnet, so the coil in the sagittal plane, center will participate in that track is followed the tracks of and the information carrier of any distortion is carried out angle modification.For reaching the characteristics that embodiment that this purpose designs has be: in all cases, above-mentioned sectional coil is formed by the active coiler part that distributes in the face of magnet and along the magnet peripheral direction with away from the coiler part of magnet.This embodiment has simple especially structure, only needs a simple control system to encourage sectional coil; When adopting three sectional coils, only need five amplifiers.Another scheme that may implement is complicated slightly in configuration aspects, but can realize efficient radial motion, its characteristics are: sectional coil is designed to coil winding, look from the magnet axis direction, winding is arranged in a row mutually, each coil of each coil winding has two parallel active coiler parts, distribute along the magnet peripheral direction, one of them active coil is partly radially adjacent with magnet, and through partly partly joining with another active coil with the magnet coil away from magnet at angle, above-mentioned another active coil partly is in the relative direction of the magnet poles of giving.

Can make above other coils of sectional coil partly are distributed in if above-mentioned toroid winding has some outwards outstanding parts, this is effective especially.The sectional coil of this embodiment according to said method designs, and with respect to the objective carrier calibration, makes the exhausted major part of sectional coil can be in the effective range in magnetic field.

According to another embodiment, wherein have at least three sectional coils all to be arranged in all cases in the outer radial plane, its magnet is made up of the annular section of two magnetic reversals, and axial one folded one ground is placed.This scanister has distinguished characteristics: toroidal magnet is sealed by toroid winding on the sagittal plane, center.

By in the sagittal plane, center, introducing toroid winding, can realize producing the axial force that focuses on usefulness with the radial magnetic field in this zone.Thereby, use this optical scanner, can obtain certain separation between coil drive axial force and the radial force by simple mode.

Because sectional coil is arranged in the outer radial plane domain, the application point of force vector is positioned at the outside of magnet center of gravity on direction of principal axis.Therefore, except three kinds of translation motions can controlling above-mentioned three axes of coordinates of object lens, can realize that also two kinds around two axles wherein rotatablely move.

In another embodiment of the invention, magnet is made up of two grading rings, embeds adapter ring between these two grading rings.This adapter ring can be made by soft magnetic material or nonmagnetic substance.Can improve the spacing of corrective action thus.

Also have in the embodiment of the present invention, adapter ring is made by permanent magnetic material and is diametrical magnetization.Improved the control action of coil field therefrom.

In another embodiment of the present invention, magnet is magnetized as a whole, and in such a way, the arctic of grading ring is on adapter ring, and the arctic of adapter ring is on their outer wall.

Another possible characteristic of the present invention is: when magnet was magnetized as a whole, the arctic of grading ring was at the outboard shafts end, and the arctic of adapter ring is on its inwall.Can improve the desired property of system like this and reduce parasite property.

In another embodiment of the present invention, coil configuration as the multi-layer conductive on the wiring board, has been simplified technological design therefrom greatly in each sagittal plane.

The more efficiently embodiment according to the present invention, magnet is made up of two grading rings, and these two annulus are diametrical magnetization in an opposite direction.By this method, can enlarge the magnetic field range that is mainly radial component, rather than be mainly the magnetic field range of axial component.In this case, to be arranged between the grading ring be very favorable to the adapter ring of axial magnetized.According to said method, axial and radial magnetic field can more clearly be separated, and can control parasitic capacity and torque better thus.

To explain various embodiments of the present invention in detail by accompanying drawing below.

Fig. 1 is scanister of the present invention synoptic diagram partly,

Fig. 2 is the parts explosion of first scheme of drive unit of the present invention,

Fig. 3 is the vertical view of drive unit shown in Figure 2,

Fig. 4 is the sectional drawing along Fig. 3 line IV-IV,

Fig. 5 is the parts explosion of the drive unit alternative plan of scanister of the present invention,

Fig. 6 is the parts explosion of the drive unit third party case of scanister of the present invention,

Fig. 7 is the skiagraph of drive unit shown in Figure 6,

Fig. 8 is the parts explosion of the cubic case of drive unit of scanister of the present invention,

Fig. 9 is the skiagraph of drive unit shown in Figure 8,

Figure 10 is the sectional drawing of the further scheme of optical scanner of the present invention,

Figure 11 is another synoptic diagram of optical scanner shown in Figure 10, also is sectional drawing,

Figure 12 is the top view of Figure 10 and one group of four sectional coil shown in Figure 11,

Figure 13 is the sketch map of Figure 10 to optical scanner shown in Figure 12,

Figure 14 is improved magnet design,

Figure 15 is further improved magnet design,

Figure 16 and Figure 17 are the further optical scanner of remodeling of magnet.

The scanister of Fig. 1 is equipped with radiation source 1, diode laser for example, and collimation lens 3 and have the lens 5 of optical axis 5A, these object lens will be installed on the objective carrier 7 of electromagnetic actuator device (below will describe in detail).Collimation lens 3 and object lens 5 can be made up of some lens, but preferably are made of the single element lens that has an aspherical refractive surface at least.In this tentative scheme, these object lens only are made up of an objective lens of being made by replica method, and objective lens is equipped with Perimeter Truss Reflector 9, and as the orientation for place system, this instructions does not give detailed description.(PHN11.416 once narrated in this orientation for place system in No. the 8501665th, HOII P; This patent continues and uses this symbol).

The divergent beams b that is sent by radiation source 1 changes the parallel beam that is full of object lens 5 apertures fully into by collimation lens 3, and object lens are focused into the radiant V of limited deflection with light beam, and overlaps with the chief ray L of light beam b.The Z axle extends vertically, and object lens must be able to move on this direction, makes light beam b be focused into luminous point V.X-axis and Y-axis are respectively radially with on the tangential direction extending with respect to the information carrier turning axle.Because luminous point V will as far as possible closely follow the tracks of the track of rotation information dish, thus require object lens and can finish along the rectilinear motion of X-axis and Z axle, and rotatablely moving arbitrarily around these.Object lens also are referred to as focus movement along moving of Z axle, and other motion then is referred to as track and follows the tracks of and the time error correction motion.

Fig. 2 to Fig. 7 at length shows some kinds of electromagnetic actuator devices of scanister of the present invention.In principle, each drive unit includes: the toroidal magnet that flexible suspension and some are installed in the fixed coil around this magnet, and these coil arrangement are in three radial zones.Magnet is annular or sleeve-shaped, is made by permanent-magnet materials.Preferably adopt magnetic material, such as neodymium-iron-boron or samarium-cobalt magnetic material with high energy storage capacity.Coil in this zone is among the special part of magnet field of magnetic forece.Do not have spurious resonance in order to make object lens can finish above-mentioned desired motion, these object lens are that magnetic is installed in the above-mentioned drive unit, and directly do not contact with other element in the scanister.

Fig. 2, Fig. 3 and Fig. 4 represent to have the drive unit of magnet 200, and magnet 200 is by axial magnetized, shown in the arrow of Fig. 4.This means at the axle two ends of magnet 200 and formed magnetic north pole N and south magnetic pole Z.Magnet 200 and the set collar 202 common objective carriers 7 that form object lens 5.Three groups of coils 204,205 and 206 are installed on the support plate 208, and coaxial with magnet 200.Each winding has the sectional coil of three burnt shapes of perfume (or spice) at least.Coil winding 204,205 and 206 is arranged along the sagittal plane of three axial separation, radially arranges with respect to magnet 200 in these three sagittal planes, and in fact is along two outer radial planes 1 and II and is positioned at intermediate radial plane among these two planes.Fig. 4 shows above-mentioned plane and object lens 5.Also show the object lens 5 that can axially move with respect to the Z axle of coil winding in the center of Fig. 4, this is the position that object lens can move up or down.On the center of above-mentioned object lens 5, outer radial plane 1 is in the direction relative with magnetic pole Z with the magnetic pole N of magnet 200 respectively with II.Sectional coil number in each coil winding 204,205 and 206 is not restricted to three, can be four or more yet.

If the axial dimension of the sectional coil winding 206 in the III of sagittal plane, center is greater than the axial dimension of sectional coil winding 204 and 205, then this is desirable.Sectional coil winding 204,205 and 206 each all be in initiatively coiler part 204a respectively, 205a and 206a place, promptly those are near the coil portion office of magnet 200, and are positioned at the useful part in the magnetic field of magnet 200.Therefore, the magnetic line of force in the above-mentioned magnetic field mainly coil winding in plane I and II 204 and 205 active coiler part 204a and 205a place distributes radially, this means: when electric current passed through, the whole winding on plane I and the II can apply axial force to magnet.Therefore, be suitable for fully producing in the coil winding 204 and 205 of sagittal plane, outside I and II and make the focus movement of object lens 5 along the Z axle.On the other hand, the active coiler part in the coil winding 206 of intermediate radial plane III is arranged in that part that the above-mentioned magnetic field magnetic line of force mainly is an axial distribution.When electric current passed through these coils, radial force was applied on the magnet 200.Follow the tracks of and the time correction for the rectilinear motion of object lens 5 with along the track of X-axis and Y-axis, can be encouraged effectively at the sectional coil winding of central area III.If the sectional coil winding 204 and 205 in side plane I and the II encourages in a different manner outside, magnetic moment also can be delivered on the magnet 200 so.This means that this drive unit also can be used for making object lens inclining to pass through a limited angle and moves around X or Y-axis, make the additional track of object lens follow the tracks of and the time correction motion becomes possibility.

Drive unit shown in Fig. 5 drive unit with above-mentioned basically is identical, therefore only sketches.Same as described above, drive unit is equipped with magnet 200, and its erecting frame 202 is fixed to object lens 5.Yet, at this situation drive unit four set of segmentation coils are housed, these coils place on four sagittal planes, and wherein two sagittal planes are corresponding to above-mentioned outer radial plane I and II, and other two sagittal planes are corresponding to above-mentioned intermediate radial plane III. Winding 204 and 205 is arranged in outer radial plane I and II and above-mentioned drive unit in a manner described, and different is the structure of the coil winding on the III of intermediate radial plane.Thus if necessary, can there be three or more sectional coil winding 206 on each intermediate radial plane, and can add axial pad between winding 206.

Fig. 6 and Fig. 7 show a kind of electromagnetic actuator device of the present invention, and in this device, the arrangement of coil is different from aforementioned schemes in the outer radial plane.Here, the movable magnet 200 that axial magnetized is also arranged in the drive unit, the erecting frame 202 of object lens 5 is housed above, as other embodiments, fixing coil along three parallel, arrange with the rectangular sagittal plane of Z axle, in side plane I and the II, toroid winding 604 is coaxial around magnet outside each.By calibrating this toroid winding position, make the magnetic line of force of magnet 200 mainly radially be distributed on the position of toroid winding 604.When toroid winding was energized, axial force was applied on the magnet 200.Thereby, can realize the focusing adjustment of object lens 5 by the activation of toroid winding 604 and 605.In the intermediate radial plane III between toroid winding 604 and 605, the sectional coil winding 606 of two banana-shaped is arranged with certain spacing.Each winding preferably is made up of three or four sectional coils, and these coils groupings are around magnet 200 ring shooting, leave air-gap mutually.In the zone that the magnetic field magnetic line that sectional coil is in magnet 200 distributes substantially vertically.This means: when sectional coil is energized, mainly be that radial force is applied on the magnet.Therefore, sectional coil winding 606 can make object lens moving linearly and moving along X-axis and Y-axis.And then, can realize the inclination of object lens by the selective excitation of sectional coil.

Fig. 8 and Fig. 9 have drawn from economic point of view and have considered, can make the interested electromagnetic actuator device of people.With regard to movable part, this drive unit is identical with above-mentioned scheme, and still, its fixing part has particular design.In this scheme, coil also along three parallel, arrange with the rectangular sagittal plane of Z axle.But in this case, have between the coil of the coil of outer radial plane I and II and intermediate radial plane III certain overlapping, as shown in Figure 9.In two outer radial plane I and II, toroid winding 804 and 805 are housed respectively.

On the position of toroid winding 804 and 805, the magnetic line of force of the magnet 200 of axial magnetized mainly radially distributes, in aforementioned schemes like that, the acting as of these coils along Z axle driving object lens.

In the III of intermediate radial plane, the sectional coil 806 of two groups of dish types is housed and separates by certain axial distance.Equally, each coil winding preferably comprises three or four coils, and these coils form a more or less airtight overcoat around magnet.Because sectional coil 806 adopts this special shape, each coil has two initiatively coiler part 806a and 806b, and these two coils are arranged in above-mentioned magnetic field.At the arrangement position of active coiler part 806a and 806b, magnetic field magnetic line mainly is an axial distribution.This arrangement mode can realize object lens not only fast but also point-device track follow the tracks of and the time correction motion.Coiler part between the active coiler part stretches out by the outshot 804a and the 805a of coil 804 and 805, can realize compact structure like this.

Figure 10 has permanent magnet 303(to optical scanner shown in Figure 13 and only schematically draws).This toroidal magnet 300 is used as objective carrier and is suspending in coil system, and its suspended pattern is not given detailed description.This coil system among the figure comprises two sectional coil windings 305, and they are arranged on 311, the 313 regional interior outer radial planes 307 and 309, two ends that are positioned at 303 of magnets.On the heart 315, the spiral winding 316 around permanent magnet 303 is arranged therein.Magnet 303 heart 315 is therein punished into two parts, and two grading ring 303a and 303b be axial magnetized in the opposite direction.This situation clearly shows out with rightabout arrow 317a and 317b in Figure 10.

The magnetic line of force 319 shown in Figure 10 shows, in the central area of magnet 315, has the magnetic line of force 321 zones, and in this zone, the most of leading thread of these magnetic lines of force is to passing through on the magnet axis 323.Yet, in terminal 311 and 313 zones, existing the magnetic line of force 325 zones, the magnetic line of force 325 is mainly axial operation with respect to magnet axis 323 in this zone.These zones with specific magnetic line of force pattern will be encouraged by various types of coils respectively, promptly on the one hand by sectional coil 305 excitations, on the other hand by toroid winding 316 excitations, be used for instrumentality mirror holder or permanent magnet 303.By the excitation of toroid winding 316, can regulate permanent magnet 303 in the axial direction, shown in Z among the figure.When sectional coil 305 was energized, magnet 303 can adjusted in the radial direction, promptly adjusted on the X of Figure 12 and Y direction.

Figure 12 represents the planimetric map of a winding of being made up of four sectional coils 305.Each sectional coil 305 is designed to pancake coil and contiguous mutually, settles along the circumference of magnet 303.Can be clear that from Figure 10 for each coil 305 that is in co-axial alignment, the electric current among its coil section 305a and the 305b is reverse.This shows that the electric current that flows acts on the magnetic field in the opposite direction in each coiler part 305a and 305b.Driving force is weakened, and for this shortcoming being carried out best remedying, outer coil cross section 305b will be as much as possible away from inner coil cross section 305a.

Figure 11 has provided the another kind of graphic representation of the optical scanner shown in Figure 10.As shown in figure 10, sectional coil 305 is in the two ends 311 and 313 zone of axle, and spiral winding 316 is in the zone at center 315 of magnet 303.

The axial length of the toroidal magnet among Figure 10 is shorter, and the length in Figure 11 and Figure 12 is then longer.Yet selecting this difference only is for problem is said clearly.In itself, the axial length of magnet is relatively lacked (being about 5 to 6 millimeters), and optical scanner is very flat thus, so in the equipment of the flat of can packing at an easy rate, for example, whole coils of each sagittal plane can be arranged as the multi-layer conductive on the wiring board.

The effect of the optical scanner of Figure 10 to Figure 12 such as same five drivers.By toroid winding 316, can axially regulate magnet 303 along Z-direction.Except sectional coil 305 had less axial action drive components, these coils had the function of radiai adjustment magnet 303 on X-axis and Y direction.If the sectional coil of each winding drives by different way on the two ends of axle, except the motion of these three directions, also can realize two kinds and rotatablely move, promptly around the motion of X-axis with around the motion of Y-axis.These five kinds possible adjustment campaigns are enough for the magnet of installing with suspended pattern 303 in the locational adjustment of all requirements.Adjust by these, can realize the desirable scanning of information carrier or be written out to information carrier ideally.

Two grading ring 303a of magnet 303 ' (Figure 14) needn't directly be connected mutually with 303b.In order to improve the Distribution of Magnetic Field in the radial zone, the adapter ring 303c that places soft magnetic material or nonmagnetic substance between permanent-magnetic clamp is feasible.If adapter ring 303c makes with permanent magnetic material, this adapter ring diametrical magnetization preferably so.Whole magnet 303 ' direction of magnetization select by a kind of like this method, promptly the magnetic north pole direction of grading ring 303a and 303b is pointed to adapter ring 303c, and the magnetic north pole of adapter ring 303c is positioned at its outer wall.

Magnet 303 " another embodiment (Figure 15) add adapter ring 303c again ".In this case, grading ring 303a " and 303b " is by the magnetization of a kind of like this method, and promptly their magnetic north pole is in two outer ends 311,313 of axle, and adapter ring 303c " magnetic north pole be positioned at inwall 327.Like this, on an axle or another axle, even on two axles, all can obtain good adjustment characteristic.Therefore, desired characteristic can improve (for example working range), and has reduced parasitic character.

In accompanying drawing 16, magnet 303 " ' by two grading ring 303a " ' and 303b " ' to form, these two rings are placed by axial one folded one ground.Grading ring 303a " ' and 303b " ' in the opposite direction at diametrical magnetization.Above grading ring 303b " ' the arctic for information carrier disc (not drawing), be inwall 331 directions, following annulus 303a along this grading ring " ' magnetic north pole then be on the outer wall 333 of this grading ring.

Figure 17 shows another kind of adapter ring 303c " ", and it is between the grading ring 303a " " and 303b " " of permanent magnetism sleeve 303 " ", and diametrical magnetization.If the supposition information disk is positioned on the sleeve 303 " ", so Shang Mian ring 303b " " is diametrical magnetization (arctic is on inwall 331) with respect to inwall, and following grading ring 303a " " is diametrical magnetization (arctic is on outer walls 333) with respect to outer wall 333.So, the arctic of the adapter ring 303c " " of axial magnetized is on the end 335 that deviates from information carrier disc of this adapter ring 303c " ", and if necessary, it also is possible putting upside down this magnetization configuration.

Claims (18)

1, be used for controlling and with the optical scanner of beam alignment on the record track of information carrier surface to be scanned, this scanister has object lens, object lens have optical axis, these object lens are equipped with an objective lens, be used for light beam is focused into analyzing spot on above-mentioned surface, this scanister also has an electromagnetic actuator device, be used for revising continuously the position of object lens with respect to information carrier, drive unit is equipped with objective carrier, it is one movable that this objective carrier has, magnet with the annular permanent-magnet material of the coaxial installation of optical axis, above-mentioned magnet is equipped with magnetic pole, drive unit also is equipped with fixing coil, this coil is arranged in the outer radial plane of two end regions of the magnet axis of centralized positioning, and via air-gap and the interaction of above-mentioned magnet, it is characterized in that, in this device, can also at least one central plane between the above-mentioned outer radial plane, arrange other coil.

2, the described optical scanner of claim 1, it is characterized in that, under any circumstance have at least three sectional coils to be arranged in the outerplanar, magnet is equipped with magnetic pole at its two ends, in this device, at least one sagittal plane, center, arrange at least three sectional coils, each sectional coil comprises the active coiler part towards magnet, (it distributes along the peripheral direction of magnet) and away from the coiler part of magnet.When peripheral direction is observed, sectional coil is mutual pyrrole neighbour (Fig. 2-5).

3, the described optical scanner of claim 2 is characterized in that, the axial dimension of the sectional coil in the sagittal plane, center greater than fringe region in the axial dimension of sectional coil.

4, the described optical scanner of claim 1, it is characterized in that, magnet is equipped with magnetic pole at the two ends of axle, coil shape in each outer radial plane is a toroid winding, and coaxial rings distributes around above-mentioned magnet, in this device, have three sectional coils on the sagittal plane, center at least, when when the magnet peripheral direction is observed, and the mutual pyrrole neighbour of this sectional coil (Fig. 6, Fig. 7).

5, the described optical scanner of claim 4 is characterized in that, each of above-mentioned sectional coil all comprises the active coiler part towards magnet, (it along magnet peripheral direction distribute) and away from the coiler part of magnet.

6, the described optical scanner of claim 4, it is characterized in that, sectional coil is the coil winding form, when when the axial direction of magnet is observed, this winding adjoins mutually, each coil of coil winding in this device all has two active coiler parts parallel, that distribute along the magnet peripheral direction, initiatively coiler part is radially adjacent with magnet for one of them, and be connected to another initiatively coiler part, in this case, the latter be positioned on the relative position of the magnet poles of giving (Fig. 8, Fig. 9).

7, the described optical scanner of claim 4 and claim 6 is characterized in that, described toroid winding has some outwards outstanding parts, can make other coiler parts distributions of sectional coil top (Fig. 8, Fig. 9).

8, the described optical scanner of claim 1, have at least three sectional coils to be arranged in the outer radial plane, magnet in this device comprises the annular section of two magnetic reversals, these two annular sections are installed by axial one folded one ground, and its toroidal magnet is sealed (Figure 10 to Figure 15) by toroid winding on the sagittal plane, center.

9, the described optical scanner of claim 8 is characterized in that, magnet is made up of two segments in a circular shape, embeds adapter ring in the middle of two segmentations.

10, the described optical scanner of claim 9 is characterized in that adapter ring is made by soft magnetic material.

11, the described optical scanner of claim 9 is characterized in that adapter ring is made up of nonmagnetic substance.

12, the described optical scanner of claim 9 is characterized in that, adapter ring is made up of permanent-magnet materials and is diametrical magnetization.

13, claim 8,9 and 12 described optical scanners is characterized in that magnet Overall magnetization in the following manner in it, and promptly the arctic of grading ring is on adapter ring, and the arctic of adapter ring is on their outer wall.

14, claim 8,9 and 12 described optical scanners is characterized in that magnet is Overall magnetization in the following manner, promptly the arctic of grading ring be at outboard shafts to end, and the arctic of adapter ring is on their outer wall.

15, the described optical scanner of claim 8 is characterized in that, the coil in each sagittal plane is arranged as the multi-layer conductive on the wiring board.

16, the described optical scanner of claim 4 is characterized in that, magnet is made up of two grading rings, and these two segmentations are diametrical magnetization (Figure 16) in the opposite direction.

17, the described optical scanner of claim 16 is characterized in that, the adapter ring of axial magnetized is placed in (Fig. 7) between the grading ring.

18, the described optical scanner of claim 7, it is characterized in that, the grading ring that direction is pointed to the information carrier disc that continues is (arctic is in the inboard) that radially is magnetized to the inside, other grading rings then are diametrical magnetizations (arctic is in the outside) laterally, and adapter ring be deviate from information carrier disc and (arctic leave message carrier plate) of axial magnetized (Figure 17).

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