KR100713543B1 - Optical Pick-up actuator - Google Patents

Abstract

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical pickup actuator, in particular an optical pickup actuator capable of reducing vibrations generated from a yoke plate.

An optical pickup actuator according to an embodiment of the present invention comprises: a lens holder for mounting an objective lens on one side; A coil installed in the lens holder inner receiving groove; A magnet opposite the coils; A yoke plate having a first yoke bent and a magnet attached to the first yoke; A second yoke coupled to the yoke plate and having an inner yoke having a magnet attached thereto to form a closed circuit; It characterized in that it comprises a wire suspension for supporting the movement of the lens holder and electrically connected to the coil.

Actuator, Lens Holder, Magnet, Coil, Yoke Plate, Vibration

Description

Optical pick-up actuator

1 is a perspective view showing an optical pickup actuator of the conventional three-axis drive type.

Figure 2 is a perspective view showing a separate optical pickup actuator conventional.

3 is a plan view for explaining the effect of the tilt drive by the tracking drive of the conventional optical pickup actuator.

4 is a perspective view illustrating main parts of a conventional tilt magnet and a tilt coil to explain tilt driving by a current;

5 is an exploded perspective view showing an optical pickup actuator according to an embodiment of the present invention.

6 is an internal configuration diagram of a lens holder magnetic circuit of the present invention.

7 is a view showing a yoke vibration reduction structure of the present invention.

(A) (b) is a coupling state diagram and its back figure for showing the yoke vibration reduction structure of this invention.

9 (a) to 9 (d) are diagrams showing yoke and vibration transmission characteristics of another yoke plater in order to be compared with the present invention.

10 is a view showing the vibration transmission characteristics in the yoke vibration reduction structure according to the present invention.

11 is a state diagram and a rear view of the coupling state of the optical pickup actuator according to an embodiment of the present invention.

<Description of the symbols for the main parts of the drawings>

100 ... actuator 101 ... receiving groove

110 Lens holder 111 Objective lens

112 ... focusing coil 113 ... tracking coil

114.Tilt coil 120 ... York plate

121 ... York 1st 122 ... York Home

123,124 Magnet 125.Frame fixing protrusion

126 ... Home 130 ... Wire Suspension

140 ... frame 141 ... substrate

150 ... First York 151 ... Inside York

152 Top yoke 153 York insertion protrusion

154 ... sitting protrusion 155 ... U-shaped groove

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical pickup actuator, in particular an optical pickup actuator capable of reducing vibrations generated from a yoke plate.

In general, in a device that reads and writes information using an optical disk, an optical pickup actuator is a device that accurately positions the laser beam passing through the objective lens on the surface and track of the disk. As the storage capacity of the optical disk increases, Increasingly, the demand for driving accuracy is increasing. As the storage capacity of the optical disk increases, the numerical aperture of the objective lens used increases, and the increase of the numerical aperture inevitably causes aberration due to the tilt of the disk. This increase in aberration, as well as deterioration in reproduction performance, causes problems in the formation of pits at the time of information recording, causing degradation of the recording signal.

For this reason, there is a need for a tilt driving device for performing correction on tilt of the disk together with focusing and tracking driving. A method for correcting tilt of the disk has been proposed. Representative methods include moving the entire actuator using a DC motor and correcting the inclination of the disc by moving only the optical pickup drive unit.

In the case of using a DC motor, only the inclination of the disk in the low frequency band can be corrected, and the overall size of the optical reproducing apparatus increases.

As a method of moving only the lens holder of the optical pickup actuator, an optical pickup actuator of a moving coil type and a moving magnet type has been proposed. However, since the movable coil type has to connect at least six wires to the driving part side for the tilt control, there is a serious disadvantage in component assembly. In the case of the movable magnet type, the sensitivity required for the objective lens of the lens holder is increased. It is difficult to secure.

Referring to FIGS. 1 to 4, a conventional triaxial drive type optical pickup actuator is described below.

In the configuration of the conventional optical pickup actuator capable of three-axis driving, an objective lens 11 for focusing a laser beam from an optical disc is provided on one side, and a tracking coil 12 and a focusing coil 13 are provided on an inner side, and a rear side of the optical pickup actuator. In order to attach the lens holder 10 to which the magnet 15 for tilt is attached, and the magnet 21 for implementing tracking and focusing driving with respect to the tracking coil 12 and the focusing coil 13, an inner and outer yoke ( 22 is bent, the yoke plate 20 having a yoke 23 for tilting at a position spaced apart from the inner and outer yokes 22, and a tracking coil 12 and a focusing coil on both sides of the lens holder 10. A plurality of wire suspensions 30 electrically connected to and installed at 13 and a fixing portion 41 for penetrating and supporting one end of the wire suspension 30 are formed on the front surface between the fixing portions 41. Yoke for inserting the yoke 23 for tilt The insertion part 42 is formed, and the frame 40 is attached to the rear surface of the substrate 43 for electrically connecting the wire suspension 30 through the fixing part 41 and the outside of the yoke insertion part 42. It is configured to include a coil for tilting (50) which is guided around and generates an electromagnetic force with respect to the tilting magnet (15).

The tilt magnets 15 are attached to each other with a polarity opposite to one side of the lens holder 10 from one tilting coil 50 as shown in the plural number.

On one side of the lens holder 10, a fitting groove 16 for accommodating a plurality of tilting magnets 15 on both sides from the center is formed. Wherein the fitting groove 16 is formed in the form that can be inserted into the tilt magnet 15, it is located on the left and right sides with respect to the center line of the lens holder 10 in which the objective lens 11 is installed.

Alternatively, the plurality of tilting magnets 15 may be attached to both sides with respect to the lens holder in which the fitting groove 16 is not formed, based on the center of the lens holder 10.

The tilt magnet 15 mounted on the fitting groove 16 and the fitting groove 16 of the lens holder 10 is formed at one side or front and rear sides according to the shape of the lens holder 10, When formed, the plurality of tilting magnets 15 are correspondingly installed on one tilting coil 50 in a configuration in which the tilting yoke 23 is correspondingly formed on the yoke plate 20 so that the tilting drive is performed. It may also be configured to implement.

Referring to the operation and effect of the conventional optical pickup actuator having a three-axis drive function configured as described above are as follows.

The focusing and tracking driving of the conventional optical pickup actuator from the driven optical disk is carried out by the magnet 21 attached to the yoke 22 on the yoke plate 20 and the focusing coil 13 and tracking coil 12 of the lens holder 10. With the electromagnetic force applied to the track, the track drive according to the focus (focus) on the optical disk and the track position from the recording surface can be used to read information or to record data.

On the other hand, the tilt driving of the optical pickup actuator for eliminating the tilt aberration due to the high speed rotation of the optical disk is a plurality of tilt magnets 15 and the yoke plate 20 inserted into the fitting groove 16 of the lens holder 10 The lens holder 10 can be tilted with an electromagnetic force generated from the tilting coil 50 guided to the tilting yoke 23.                         

More specifically, as shown in FIG. 4, the plurality of tilting magnets 15 installed on the center line of the lens holder 10, that is, the center reference line on which the objective lens 11 is located, are positioned at the same position. The polarities (N pole and S pole) are installed opposite to each other, and can be tilted by the generation of electromagnetic force from the tilting coil 50 installed at a predetermined interval therebetween. ) Represents the direction of the electromagnetic force, the letter (i) represents the current direction flowing to the tilting coil 50, the letter (F) due to the interaction between the letter (B) and the letter (i) Lorentz force (Lorentz) force).

That is, the current flows in a constant direction, but since both tilt magnets 15 are positioned opposite to each other, the lens holder 10 provided with the objective lens 11 is paired, and the pairing occurs in the X axis. Since it corresponds to the moment of the direction is to be tilt-driven like a seesaw based on the X-axis of the lens holder 10.

Such driving is spaced apart from the position where the tilting magnet 15 and the tilting coil 50 are installed with the focusing coil and the tracking coil 12. As shown in FIG. May implement a separate tilt drive.

In the implementation of the conventional tracking motion, since the size of the gap dx between the tilt magnet 15 and the tilt coil 50 according to the tilt driving of the present invention can be kept constant, eventually tilt There is almost no change in magnetic flux between the magnetic magnet 15 and the tilt coil 50.

Accordingly, as compared with the conventional hybrid type optical pickup actuator, the air pickup actuator of the present invention has a space between the tilt magnet 15 and the tilt coil 50 due to the electromagnetic force generated by the tilt magnet. By implementing the tilt drive in the range of the minimum interval without disturbing the tracking drive and focusing drive range in the state, there is an advantage that the output constant in the tilting direction can be increased.

In the optical pickup actuator, a plurality of tilt magnets 15 installed at the lens holder 10 side are installed at both sides, and the yoke inserting portion 42 is disposed at the front of the fixing portion 41 of the frame 40 at the position corresponding thereto. Independently installed through the coil for tilt 50 is able to perform three-axis drive (focusing, tracking and tilting drive) as described above.

However, by separately installing the tilt magnet behind the lens holder, not only the size of the lens holder increases but also the weight of the lens holder increases, there is a problem of poor productivity and sensitivity.

In addition, there is a problem in that a separate insertion structure and a support structure must be provided to form a magnetic circuit for the radial tilt.

In addition, since the wire suspension connected to the coils uses four wire springs and two stranded coil springs for three-axis driving, productivity is very difficult.

In addition, since the center of the radial tilt is located behind the lens holder during the radial tilt driving, there is a problem that an offset occurs in the Z-axis direction.

In addition, since the yoke plate and the inner yoke, the outer yoke, and the conventional yoke for attaching the magnet for the three-axis drive, and the tilt yoke is bent and protruded in the "b" shape from the yoke plate Vibration generated in the yoke for the tilt, etc. has a characteristic that almost 100% is transmitted to the yoke plate, there is a problem that the characteristics of the pickup due to vibration deteriorate. In addition, since the yoke is integrally bent, there is a difficulty in mold processing, and the yoke plate and the frame are difficult to fasten.

The present invention has been made to solve the above problems, an object of the present invention is to provide an optical pickup actuator formed by bending the main yoke in the yoke plate and to form the other yoke separately to be fixed to the yoke plate.

Another object of the present invention is to provide an optical pickup actuator that is capable of bending a main yoke to a yoke plate and fixing another yoke bent to face between the yoke plate and the main yoke with an adhesive.

Optical pickup actuator according to the present invention for achieving the above object,

A lens holder for mounting an objective lens on one side; A coil installed in the lens holder inner receiving groove; A magnet opposite the coils; A yoke plate having a first yoke bent and a magnet attached to the first yoke; A second yoke coupled to the yoke plate and having an inner yoke having a magnet attached thereto to form a closed circuit; It characterized in that it comprises a wire suspension for supporting the movement of the lens holder and electrically connected to the coil.                     

Preferably, the second yoke is characterized in that it comprises a plurality of inner yoke, the lower end is vertically molded with respect to the yoke plate, and the upper yoke bent integrally from the inner yoke and seated on the first yoke.

Preferably, the inner yoke is characterized in that a plurality of single-pole magnets facing the magnet is attached to each other, and is erected up to the yoke plate through a coil formed in the lens holder.

Preferably, the protrusion protruding from the lower end of the inner yoke is coupled to the yoke guide groove formed in the plurality of yoke plate, and is fixed between the protrusion and the yoke guide groove with an adhesive.

Preferably, the other side of the upper yoke to form a mounting projection and the adhesive insertion groove which is seated on the upper surface of the first yoke at a predetermined position facing the upper surface of the first yoke, characterized in that the adhesive insert groove fixed It is done.

Preferably, the inner surface of the first yoke and the second yoke is characterized in that the jaw for adjusting the height of the magnet is formed.

Hereinafter, with reference to the accompanying drawings as follows.

5 is a perspective view of a slim type optical pickup actuator according to an exemplary embodiment of the present invention, and FIG. 6 is an exploded perspective view illustrating an internal configuration of a lens holder.

Referring to FIGS. 5 and 6, the objective lens 111 protruding from one side is mounted and a plurality of focusing coils 112 are installed therein, and a tracking coil 113 and an upper surface of the focusing coil 112 are provided on the front surface. A lens holder 110 in which the tilt coil 114 is installed; A yoke plate (120) having a first yoke (121) bent from a distal end thereof so as to be located in the receiving grooves (101, 102) of the lens holder (110); A second yoke 150 that integrates the inner yoke 151 and the upper yoke 152 that are bent in a "b" shape to the first yoke 121 and the yoke plate 120; A two-pole magnet 123 and a plurality of single-pole magnets 124 attached to inner surfaces of the first yoke 121 and the inner yoke 151, respectively; Three pairs of wire suspensions (130) each supporting both sides of the lens holder (110) for supplying current to the coils (112, 113, 114); And a main body 141 supporting the wire suspension 130 and attached to the rear surface of the frame 140 fixed to the rear surface of the yoke plate 120 and supplying power to the coils 112, 113, and 114. .

Here, the focusing coil 112 is installed in two horizontally wound coils are connected in series and divided into left and right centers around the polar boundary of the two-pole magnet 123 and fitted into the receiving groove 101. The inner yoke 151 and the unipolar magnet 124 are attached to each of the inner parts. The tracking coil 113 is attached to the center of the focusing coil 112 to face the polar boundary of the two-pole magnet 123, the tilt coil 114 is on the upper surface of the focusing coil 112 It is mounted and is configured to face the two-pole magnet 123.

In addition, the two-pole magnet 123 may be composed of a single magnet of a multi-pole magnetized or two magnets of a single-pole magnetized, it is arranged with a polarity opposite to the polarity of the opposing single-pole magnet.

Referring to the accompanying drawings, the slim type optical pickup actuator configured as described above is as follows.

First, referring to FIGS. 5 and 6, the optical pickup actuator 100 mounts the objective lens 111 at one upper end of the lens holder 110, and installs coils 112, 113, and 114 inside the lens holder 110. do.

In addition, the two-pole magnet 123 is fixed to the inner surface of the first yoke 121 bent from the yoke plate 120 at a position opposite to the coils 112, 113, and 114, and at a position opposite to the two-pole magnet 123. A plurality of unipolar magnets 124 are attached to the inner yoke 151 of the second yoke 150.

The lens holder 110 has a plurality of focusing coils 112 connected in series to the inner accommodating grooves 101 and a tracking coil 113 attached to the front surface of the focusing coil 112 to face the polar boundary of the two-pole magnet 123. ) And a tilt coil 114 attached to the upper surface of the focusing coil 112 to form a magnetic circuit with the magnets 123 and 124 and to operate in multiple axes.

To this end, as shown in FIGS. 5 and 7, the lens holder 110 is provided with a receiving groove 101 for accommodating a magnetic circuit therein. A plurality of focusing coils 112 connected in series in the inner circumference of the receiving groove 101 are installed left / right around a polar boundary of the two-pole magnet 123, and the center of force and the focus force of the lens holder 110 are provided. This will match. In addition, a tilt coil 114 is provided on the upper surface of the focusing coil 112. Accordingly, the sensitivity can be maximized while minimizing the flux FLUX where the two focusing coils 112 meet.                     

The tracking coil 113 is vertically wound and its center is opposite to the polar boundary of the two-pole magnet 123 and is attached to the front of the focusing coil 112, that is, the direction of the objective lens 111, between the receiving grooves 101. Is fitted and fixed.

The tilt coil 114 is attached to the upper surface of the plurality of focusing coils 112 so that the radial tilt center can be installed as close as possible to the center of the objective lens 111, thereby securing productivity and a focus moving range. Can be. In addition, by minimizing the offset between the force center of the tilt coil 114 and the Z-axis optical center for tilting the objective lens when driving in the radial tilt direction, the optical characteristics of the radial tilt are optimized. Coupling state diagram of such an actuator is shown in Figure 11 (a).

Meanwhile, the structure of the yoke will be described with reference to FIGS. 5 to 8. 7 and 8 are views showing the vibration preventing structure of the yoke of the present invention.

5 to 8, a plurality of first yokes 121 and a focusing coil 112 are respectively provided in the yoke plate 120, each of which is bent from its distal end and protrudes into the receiving groove 101. It consists of a second yoke (150) of the shape "a" is coupled oppositely.

The second yoke 150 has a structure in which the inner yoke 151 and the upper yoke 152 are integrally bent in a "-" shape. Here, the upper yoke 152 may constitute a closed magnetic circuit of the internal magnetic circuit.

Then, the second yoke 150 forms a yoke insertion protrusion 153 protruding from the lower end of the inner yoke 151, the yoke plate 120 is formed with a guide groove 122 of the "T" shape, The yoke insertion protrusion 153 is formed in a wider structure.

In addition, the mounting protrusion 154 protrudes from the front end of the upper yoke 152 of the second yoke 150 to form a U-shaped groove 155 on the left and right sides thereof, thereby reducing the contact surface with the outer yoke 121. . The mounting protrusion groove 121a is formed at the center of the upper end of the first yoke 121 corresponding thereto. Then, the seating protrusion 154 of the upper yoke 152 of the second yoke 150 is seated in the seating protrusion groove 121a formed in the upper portion of the first yoke 121, and of the U-shaped groove 155 Since the outer end is opposed to the inner surface of the upper end of the first yoke, the structure is exposed to the hole.

In addition, a second pole magnet 123 that is a main magnet is attached to the first yoke 121 of the yoke plate 120, and an inner surface of the inner yoke 151 branched into a plurality of second yokes 150 is a single pole that is an auxiliary magnet. The magnet 124 is attached to face the two-pole magnet 123.

Here, at the lower end of the first yoke 121, a protrusion 121b may be formed to adjust or restrict the height of the two-pole magnet 123 and the height of the two-pole magnet 123 in the X and Y directions. The protrusion 121b is formed as a jaw, for example, as a circular protrusion.

In addition, the bending side of the upper yoke 152 of the second yoke 150, that is, a height protruding downwardly into the inner surface of the upper yoke 152 corresponding to a portion where the inner yoke 151 and the upper yoke 152 are bent to each other. Attach the control plate 156. That is, the height of the single pole magnet 124 attached to the inner surface of the inner yoke 151 from the yoke plate 120 can be adjusted to be positioned at substantially the same height as the height of the two-pole magnet 123.

As shown in FIG. 7, jig guide holes 127 and 128 are formed at a lower end of the yoke plate 120 to align the center axis of the lens holder 110. Since the second yoke 150 is separately bent and fixed to the yoke plate 120, a space can be secured in the center of the yoke plate 120, and thus, a plurality of jig guide holes 127 and 128 are provided at the center and left / right. ) Can be formed.

8 and 10, the rear end of the yoke plate 120 forms a frame fixing protrusion 125 and a left / right guide groove 126 that are joined to the frame 140, and face each other. The yoke plate 120 and the frame 140 are formed by forming the fixing protrusion guide groove 140a and the left / right guide protrusion 140b at the center position of the frame 140. After the frame 140 is assembled and fastened to the rear end of the yoke plate 120, the lens holder 110 is seated forward, and then the 2-pole magnet 123 is attached to the inner surface of the first yoke 121.

8 and 11, after attaching the monopole magnets 124 to the inner surfaces of the inner yokes 151 of the second yoke 150, the first yokes 121 of the yoke plate 120 are attached. The yoke type engaging protrusion 153 of the second yoke 150 is joined to the upper surface of the inner yoke guide groove 122 and the seating protrusion 154 is joined to the seating protrusion groove 121a.

At this time, the UV adhesive is applied to the U-shaped groove 155 of the portion where the second yoke 150 and the first yoke 121 are temporarily coupled between the two yoke surfaces 121 and 152 to attenuate the generated vibration. Apply.

In addition, as shown in FIG. 11B, when the lower protrusion 153 of the inner yoke 151 of the second yoke 150 is fitted into the guide groove 122, the empty space of the guide groove 122 is combined. UV adhesive is applied to the yoke plate 120 to reduce the transmission to the yoke plate 120. Here, the yoke guide groove 122 has a structure that is substantially the same as the length of the protrusion 153 and the width is extended to the outside, it is provided with a space that can be sufficiently applied UV adhesive even if combined.

On the other hand, for the vibration energy transfer characteristics in another yoke structure similar to the yoke structure of the present invention when comparing the vibration by the structure of Figure 9 and 10 as follows.

9 is a structure without vibration reduction characteristics, (a) and (b) are front perspective views, and (c) and (d) are rear perspective views. As shown in (a), the outer yoke 221 and the inner yoke 251 are bent and protruded from the yoke plate 220, and as shown in (b), the upper yoke 255 is covered and coupled. However, in this structure, as shown, the vibration force (F) generated in the inner yoke 251 and the upper yoke 255 is transmitted to the yoke plate 220, the structure is not reduced the vibration is transmitted. .

In contrast, Figure 10 is a vibration reducing structure of the present invention, (a) is a front perspective view and (b) is a rear perspective view. As shown in FIG. 10A and 10B, the second yoke 150 is separated from the yoke plate 120, and the inner yoke 151 of the second yoke 150 is separated from the yoke plate 120. Since the vibration damping UV adhesive is applied to the space between the protrusion 153 and the groove 122 of the yoke plate 120, it not only strengthens the supporting structure but also transfers it from the inner yoke 151 of the second yoke 150. The vibration which is caused is reduced.

In addition, since the UV adhesive is applied to the U-shaped groove 155, which is an adhesive insertion groove formed at a position where the upper yoke 152 and the first yoke 121 of the second yoke 150 are separated and faced, the first yoke is applied. Vibration generated from 121 is relatively less vibration than the structure of Figure 9, there is a vibration reduction effect.

That is, as shown in FIG. 9, the vibration in the yoke plate 220 having the inner yoke 251 as one body is directly transmitted in the direction of the yoke plate 220 and the frame 240. In the structure of the present invention as shown in FIG. 10, by using the inner yoke 151 of the second yoke 150 and the vibration-absorbing UV adhesive, the vibration energy of the inner yoke is dispersed and absorbed by itself, thereby minimizing the effect of the actuator assembly. It is possible to maximize the efficiency of the optical pickup.

In addition, since the inner yoke 151 is separately formed and molded from the yoke plate 120, the strength of the yoke plate 120 may be improved and vibration energy may be dispersed.

As such, since only the first yoke 121 is bent from the yoke plate 120, and the remaining yoke 150 is separately molded and combined, the vibration generated in the yoke 150 is combined. It is reduced in, not transmitted to the yoke plate 120 and the frame 140 is improved vibration characteristics in the pickup.

In the present invention, the yoke vibration reduction structure of the three-axis drive actuator is characterized in that the present invention is applicable to a two-axis drive actuator. That is, in the structure in which the accommodating groove is formed in the lens holder and the magnet and the coil are arranged, all of them are applicable. Also, a 2-pole magnet or a single-pole magnet may be attached to the first yoke, and a single-pole magnet may not be attached to the inner surface of the inner yoke. This vibration reduction feature is preferably applied to not only a slim optical pick-up actuator but also a desktop optical pick-up actuator, and is applicable to both a moving coil or a moving magnet type.

So far, the present invention has been described with reference to the preferred embodiments, and those skilled in the art to which the present invention pertains to the detailed description of the present invention and other forms of embodiments within the essential technical scope of the present invention. Could be implemented. Here, the essential technical scope of the present invention is shown in the claims, and all differences within the equivalent range will be construed as being included in the present invention.

As described above, the optical pickup actuator according to the present invention separates the yokes other than the main yoke from the yoke plate to reinforce the strength of the yoke plate, and combines the other yokes together with the yoke plate to form a separate yoke. The vibration transmitted from the yoke plate to the yoke plate is attenuated.

Claims (6)

A lens holder; A coil installed in the lens holder inner receiving groove; In the optical pickup actuator comprising a wire suspension for supporting the movement of the lens holder and electrically connected to the coil, A yoke plate formed by bending a first yoke having a magnet attached thereto; A second yoke having a plurality of inner yokes coupled to the yoke plate and an upper yoke attached to an upper surface of the first yoke; When the inner yokes are coupled to the yoke plate, the protrusions projecting at the bottom of the yoke are inserted into the plurality of yoke guide grooves formed on the yoke plate, and then the UV adhesive is introduced into the space provided between the protrusions and the yoke guide grooves, and fixed. , When the upper yoke is attached to an upper surface of the first yoke, the upper yoke is seated on a seating protrusion seated on the upper surface of the first yoke, and then the UV adhesive is injected into and fixed to the adhesive insertion groove provided on the upper surface of the first yoke. Optical pickup actuator, characterized in that. delete The method of claim 1, And the inner yoke is attached to a plurality of single pole magnets facing the magnet, respectively, and is configured to stand up to the yoke plate through a coil configured in the lens holder. delete delete The method of claim 1, The inner surface of the first yoke and the inner surface of the second yoke is provided with a jaw for adjusting the height of the magnet is optical pickup actuator.

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