KR20050047742A - Actuator for optical pick-up including coil pattern - Google Patents

Abstract

The present invention provides an optical pickup actuator capable of performing a tilt drive using a PCB coil having a coil pattern provided therein, wherein an objective lens for focusing light is provided on one side, and a focusing coil and a first inside are provided. A blade provided with first and second tracking coils, a first magnet installed inside the focusing coil, and a second magnet installed outside the first and second tracking coils; A PCB coil installed for tilt driving outside the focusing coil; Third and fourth magnets disposed horizontally on the same plane and spaced apart from the left and right from the center of the blade between the outer side of the focusing coil and the PCB coil to generate a magnetic field for tilt driving; And a first yoke and a spacer yoke for forming a magnetic field between the first magnet and the second magnet are formed inside the focusing coil, and a second yoke for focusing the magnetic field of the second magnet includes a second yoke of the second magnet. It is formed on the outside, and includes a yoke plate formed on the outside of the PCB coil to focus the magnetic fields of the third and fourth magnets.

Description

Actuator for optical pick-up including coil pattern

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an actuator for optical pickup using a coil pattern, and more particularly, to an actuator capable of performing a tilt drive using a PCB coil having a coil pattern therein.

In general, an optical pickup device is a device for reproducing signals recorded on various optical disks or recording signals on optical disks. DVD and CD products are widely used nowadays.

Of course, DVD products such as DVD-ROM, DVD-P, DVD-R, DVD-RW, DVD-RAM, etc. have high capacity technology, but most people are relatively inexpensive and widely used CD-ROM, CD Are more familiar with CD products such as R, CD-RW, and CD-P.

Therefore, even if a DVD product has a high capacity technology, it cannot survive in the market unless it is compatible with a CD product. For this reason, a product having both a DVD function and a CD function is marketed in the current market.

According to the configuration of the optical pickup device, the base coupled to the main axis and the minor axis and reciprocating along the axial direction, the light beam is installed on the upper surface of the base and move together with the base to converge and focus to one point of the optical disk It consists of an actuator.

In addition, the optical pickup actuator is a device for accurately positioning the laser beam passing through the objective lens on the surface and the track of the optical disk. As the storage capacity of the optical disk increases, the demand for driving accuracy is gradually increased and its importance This situation is increasing. Thus, 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 tilt of the optical 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, the optical pickup actuator needs a tilt drive for performing the correction of the tilt of the optical disk together with the focusing and tracking driving, and thus a method for correcting the tilt of the optical disk has been proposed. . Representative methods include moving the entire actuator using a DC motor and correcting the inclination of the optical disc by moving only the optical pickup driving unit.

Here, the method using the DC motor has a problem that it is possible to correct only the tilt of the optical disk in the low frequency band and that the overall size of the optical reproducing apparatus is increased.

As a method of moving only the blade of the optical pickup actuator, an optical pickup actuator of a moving coil type and a moving magnet type has been proposed. However, the movable coil type has a serious disadvantage in component assembly since at least six wires must be connected to the driving part side for tilt control, and the movable magnet type secures the required sensitivity of the objective lens of the blade. The disadvantage is that it is difficult to do.

Hybrid type has been proposed for the purpose of supplementing these disadvantages, but this also has a disadvantage in that it is difficult to secure the required sensitivity.

In order to solve the problems described above, Patent Application No. 2002-19610 focuses the laser beam from the optical disk by changing the design of the position where the tilt magnet and the tilt coil are installed regardless of focusing or tracking driving. An optical pickup actuator having a three-axis driving function capable of smoothly performing tilt driving as well as focusing and tracking driving of a blade is proposed.

Then, the structure and operation of the conventional optical pickup actuator having a three-axis drive function proposed in the patent application No. 2002-19610 with reference to FIG.

As shown in FIG. 1, in the conventional optical pickup actuator, an objective lens 11 for focusing a laser beam from an optical disk is provided on one side, and a tracking coil 12 and a focusing coil 13 are installed inside. Inner and outer yoke for attaching the blade 10 having the tilt magnet 15 attached to the rear and the magnet 21 for implementing tracking and focusing driving with respect to the tracking coil 12 and the focusing coil 13. A yoke plate 20 formed with a plurality of tilt yokes 23 and 24 formed to be bent, and corresponding to the tilt magnet 15 at positions spaced apart from the inner and outer yokes 22 by a predetermined distance; A plurality of wires 30 electrically connected to the tracking coil 12 and the focusing coil 13 are formed on both sides of the blade 10, and a fixing portion 41 for supporting one end of the wire 30 is formed. And a plurality of yoke shovels between the fixing portions 41 The parts 42 and 43 are formed, and the wire holder 40 to which the printed circuit board (PCB) 44 which connects the wire 30 at one end is attached, and the some yoke 23 and 24 for the tilts, respectively. It is installed in the guide is composed of a tilting coil (50-1, 50-2) for generating an electromagnetic force with respect to the tilting magnet (15).

Here, the tilting magnets 15 are positioned from the center of the rear side of the blade 10 to the plurality of tilting coils 50-1 and 50-2 corresponding to each other, and the tilting coils 50-1 and 50- are provided. The corresponding face for 2) is positioned and attached with the same polarity.

On the other hand, the blade 10 is classified into two types according to the optical pickup actuator, the objective lens 11 is installed on one side, the tilt magnet (attached to the back of the blade in the opposite direction of the objective lens 11 position ( 15) and the tilt coils 50-1 and 50-2 are applied to the optical pickup actuator for the slim type CD player, and another one is provided with the wire 30 based on the objective lens 11. The tilting magnet 15 and the tilting coils 50-1 and 50-2 on the front and rear sides of the blade in the longitudinal direction can be applied to the optical pickup actuator for a CD or DVD player, respectively.

The principle of tilt driving of a conventional optical pickup actuator having such a structure will be described with reference to FIG. 2 as follows.

As shown in FIG. 1, the tilt coils 50-1 and 50-2 are inserted into the yoke insertion parts 42 and 43 into which the plurality of tilt yokes 23 and 24 are inserted on the yoke plate 20, respectively. Correspondingly, the two tilting magnets 15 installed on the rear side of the blade 10 can be tilted to realize the tilt driving.

Referring to the principle of the tilt drive for this, as shown in Figure 2, the current in the tilt coil of any one of the tilt coil (50-1, 50-2) installed in each of the tilt yoke (23, 24) When the direction of i is reversed, the tilt magnet 15 is located in accordance with the current direction derived from the corresponding plurality of tilt coils 50-1 and 50-2 even if the tilt magnet 15 is provided with the same polarity. The direction of movement of 15 is generated upside down to implement tilt driving of the blade 10.

In Fig. 2, the magnetic field B represents the direction of the electromagnetic force, the current i represents the current direction flowing to the tilt coil 50, the force F is a Lorentz force generated due to the interaction between the magnetic field B and the current i to be.

However, in the case of the tilt coil provided in the conventional optical pickup actuator as described above, since the number of windings is at least 250 lines, it is very difficult to wind the coil in the manufacturing process, and also because the wound thin coil is exposed to the outside. There was a problem in that the coil was disconnected or the constant winding state was released during tilt driving.

The present invention has been made to solve the above problems, and an object of the present invention is to provide an actuator for optical pickup that can perform a tilt drive using a PCB coil having a coil pattern provided therein.

An object of the present invention is to provide an actuator for optical pickup that can simplify the manufacturing process and make the shape of the product compact by attaching a separately manufactured PCB coil instead of the coil winding directly on the manufacturing process.

An object of the present invention is to provide an actuator for optical pickup that can reduce the probability that the coil is damaged during the tilt driving compared to the coil exposed to the outside by providing a coil pattern for the tilt driving inside the PCB.

In order to achieve the above object, the present invention provides an objective lens for focusing light on one side, a focusing coil and first and second tracking coils are installed inside, and a first magnet inside the focusing coil. A blade installed and having a second magnet installed outside the first and second tracking coils; A PCB coil mounted to the tilt driving to be spaced apart from the outside of the focusing coil; Third and fourth magnets arranged horizontally on the same plane, spaced apart from the left and right from the center of the blade between the outer side of the focusing coil and the PCB coil to generate a magnetic field for tilt driving; And a first yoke and a spacer yoke for focusing the electric field of the first magnet are formed inside the focusing coil, and a second yoke for focusing the magnetic field of the second magnet is outside the second magnet. And a yoke plate formed outside the PCB coil to focus the magnetic fields of the third and fourth magnets.

Hereinafter, with reference to the accompanying drawings will be described in detail a preferred embodiment of the present invention.

3 is an external perspective view of an optical pickup actuator using a coil pattern according to an embodiment of the present invention.

Figure 4 is a perspective view of the main portion of the optical pickup actuator using a coil pattern according to an embodiment of the present invention, showing the structure of the tracking coil, the focusing coil and the PCB coil which is the driving force of the three-axis drive in more detail.

Referring to the configuration of the actuator according to the present invention with reference to Figures 3 and 4, the objective lens 111 for focusing light, the focusing coil 112 for moving the actuator in the vertical direction, and the agent for moving the actuator in the left and right directions A blade 110 provided with the first and second tracking coils 113 and 114 and a first yoke 121 for focusing driving are formed inside the focusing coil 112 and a spacer yoke for preventing dispersion of a magnetic field. The yoke plate 120 and the focusing coil 112 are formed with a spacer yoke 122 and a second yoke 123 for tracking driving is formed outside the first and second tracking coils 113 and 114. Is electrically connected to the printed circuit board (PCB) coil 130 and the focusing coil 112 and the first and second tracking coils 113 and 114 that are installed to tilt the outside of the Of the plurality of wires 140 and the plurality of wires 140 A flexible printed circuit board (FPCB) attached to the outside of the wire holder 150 to apply current to the wire holder 150 and the PCB coil 130 and the plurality of wires 140 connected to the side ends and fixed thereto. (160).

In the blade 110, an objective lens 111 for focusing a laser beam on an optical disk is attached to one side, and the size of a spot that changes due to irregular movement of the optical disk during optical signal reproduction is fixed to a predetermined size. Focusing coils 112 for moving the actuators in the up and down directions to be provided are provided therein, and the first and second tracking coils 113 and 114 for moving the actuators in the left and right directions to follow the tracks of the optical disc currently being reproduced. It is installed outside the focusing coil 112, the first and second tracking coils 113, 114 are spaced at regular intervals and mounted symmetrically on the same plane.

Here, inside the focusing coil 112 having a tetrahedral shape having a space therein, a first magnet 115 generating a magnetic field for focusing driving is attached and a magnetic field generated from the first magnet 115. The first yoke 121 for focusing and the spacer yoke 122 for refocusing the magnetic field is mounted to prevent the magnetic field from being dispersed to the outside, the first magnet 115, the first yoke 121 And the spacer yoke 122 is formed to be constantly arranged.

In addition, the blade 110 is equipped with a second magnet 116 that generates a magnetic field for tracking driving on the outside of the first and second tracking coils 113 and 114, and focuses the magnetic field generated therefrom. The second yoke 123 is arranged in a line with the second magnet 116, the third and fourth magnets 117, 118 for generating a magnetic field for the tilt drive is the focusing coil 112 And a PCB coil 130. In this case, the third and fourth magnets 117 and 118 are formed to be spaced apart from the front surface of the PCB coil 130 (the objective lens direction), and are spaced left and right from the center of the rear surface of the blade 110 as a starting point. And arranged horizontally on the same plane.

The yoke plate 120 is formed with a first yoke 121 that is bent inside the focusing coil 112 to attach the first magnet 115 for focusing driving, and to prevent dispersion of the magnetic field. A spacer yoke 122 is formed to be arranged in line with the first yoke 121, and a second magnet 116 for driving driving formed on the outside of the first and second tracking coils 113 and 114 is attached. The tracking drive second yoke 123 is formed, and the third yoke 124 for concentrating the magnetic field generated from the third and fourth magnets 117 and 118 to the PCB coil 130 is provided. Is formed. Here, the third yoke 123 is disposed on the rear surface (the FPCB direction) of the PCB coil 130.

Each of the plurality of wires 140 is disposed to be exposed to both sides of the blade 110 so that one end thereof is electrically connected to the tracking coil 12 and the focusing coil 13, and the other end thereof is connected to the wire holder 150. .

The wire holder 150 is disposed on the opposite side of the objective lens 111 to fix the plurality of wires 140.

The FPCB 160 supplies a current applied from the outside to the focusing coil 112, the first and second tracking coils 113 and 114, and the PCB coil 130.

On the other hand, the blade 110 is classified into two types according to the optical pickup actuator, for example, the objective lens 111 is installed on one side, attached to the back of the blade 110 which is the opposite side of the objective lens 111 position It is applied to the optical pickup actuator for the slim type CD player of the structure in which the tilting magnet and the tilting coil correspond to each other, and the other is the front and rear side of the blade in the longitudinal direction in which the wire 140 is installed based on the objective lens 111. The tilt magnet and the tilt coil may be applied to an optical pickup actuator for a CD or DVD player having a corresponding structure, respectively.

In addition, an implementation example of the PCB coil 130 for tilt driving will be described in more detail as follows.

5 is a cross-sectional view of a coil pattern showing an embodiment of a PCB coil provided in the optical pickup actuator of the present invention.

As shown in FIG. 5, the coil pattern is formed in a planar shape, but the first primary side coil pattern 131 and the second secondary side coil pattern 132 having the same shape for the tilt driving in the form of a seesaw operation have the center of the blade 110. The parts are formed so as to be spaced symmetrically from side to side. As such, after the first and second coil patterns 131 and 132 are formed, the coil coils 131 and 132 may be coated with a PCB to prevent the coil patterns 131 and 132 from being exposed to the outside, thereby implementing the PCB coil 130. do.

The tilt driving principle of the PCB coil implemented as described above will be described with reference to FIGS. 6A and 6B.

FIG. 6A illustrates an upper side surface of the PCB coil 130, the third and fourth magnets 117 and 118, and the third yoke 124 disposed in the actuator as shown in FIG. 3. Here, the N pole which generates the magnetic field among the S pole and the N pole of the magnet is arranged in the direction of the PCB coil.

Since the PCB coil is arranged as shown in FIG. 6A, the magnetic field generated from the N pole of the magnet is focused in the direction of the PCB coil, whereby the magnetic field is not distributed to the PCB coil by the yoke positioned on the opposite side of the magnet. Focused

FIG. 6B illustrates a flow direction of current in a PCB coil to which a magnetic field is applied as shown in FIG. 6A.

In FIG. 6B, the left side shows the current flow of the first side coil pattern 131, and the right side shows the current flow of the second side coil pattern 132.

In the state where the magnetic field B is applied as shown in FIG. 6A, when the current I of the first primary side coil pattern 131 on the left side flows in the right direction, the force F acts upward in accordance with the flaming left hand law.

Similarly, when the magnetic field B is applied as shown in FIG. 6A, when the current I of the second secondary coil pattern 132 on the right side flows in the left direction, the force F acts downward in accordance with the flaming left hand law.

Here, the force F becomes a power source for tilting the actuator.

As described above, since the left and right sides of the actuator operate in a vertical direction by the currents applied in different directions, the actuator according to the present invention is to be tilted by the PCB coil.

Figure 7a is a front view of a coil pattern showing another embodiment of the PCB coil provided in the optical pickup actuator of the present invention.

FIG. 7B is a top side view of the coil pattern implemented as in FIG. 7A.

In FIGS. 7A and 7B, coils are wound around two magnetic bodies 133 and 134 so as to have the same number of turns, respectively, to form a coil pattern. The first and second coil patterns 135 and 136 formed as described above are arranged to be spaced symmetrically from side to side with the center portion of the blade 110 as a starting point, and then the coil patterns 135 and 136 are formed. The PCB coil 130 is implemented by coating a PCB on the outside so as not to be exposed to the outside.

The tilt driving principle of the PCB coil implemented as described above is the same as described with reference to FIGS. 6A and 6B.

On the other hand, when the coil pattern is implemented by inserting a magnetic material as shown in Figure 7a and 7b, the magnetic material is to focus the applied magnetic field to the coil adjacent to the magnet, so that the magnetic field generated between the coils separated on both sides around the magnetic material Interference can be prevented.

As described above, in the present invention, by attaching a separately manufactured PCB coil to the actuator instead of the tilt coil directly wound on the manufacturing process, the manufacturing process is simplified compared to the conventional, and the PCB is not exposed to the outside. The coil pattern was provided in the inside, and the shape of the product was made compact.

The three-axis driving of the optical pickup actuator using the PCB coil according to the present invention having the above configuration will be described in detail as follows.

First, focusing driving will be described.

When the laser beam is focused on the optical disc through the objective lens 111 in order to reproduce data recorded on the optical disc or record new data on the optical disc, spot size fluctuates due to irregular movement of the optical disc. Is generated.

When this phenomenon occurs, the focusing coil 112 moves the actuator in the vertical direction to prevent the spot size from being changed. In this case, the focusing driving is performed by the Lorentz force generated by the current applied through the plurality of wires 140 and the magnetic field formed between the first and second magnets 115 and 116 applied to the focusing coil 112. Is done.

Here, the magnetic field formed between the first and second magnets 115 and 116 is focused on the focusing coil 112 by a magnetic circuit constituted by the first yoke 121, the spacer yoke 122, and the second yoke 123. Focused on).

Next, the tracking drive will be described.

When the laser beam is focused on the optical disc through the objective lens 111 to reproduce data recorded on a specific track of the optical disc or record new data on a specific track, the data may be caused by irregular movement of the optical disc from side to side. A situation arises in which the track being recorded or played back is out of sync.

When such a deviation of the track occurs, the first and second tracking coils 113 and 114 move the actuator in the left and right directions to follow the track currently being recorded and reproduced. In this case, the tracking driving is performed by applying a current applied through the plurality of wires 140 and a magnetic field formed between the first and second magnets 115 and 116 to the first and second tracking coils 113 and 114. By the force of Lorentz generated.

Here, the magnetic field formed between the first and second magnets 115 and 116 is formed by the first and second magnets 121, the spacer yoke 122, and the magnetic circuit formed by the second yoke 123. 2 are focused on the tracking coils 113 and 114.

Finally, looks at the tilt drive by the PCB coil according to the present invention.

When the laser beam is focused on the optical disk through the objective lens 111 to reproduce data recorded on the optical disk or record new data on the optical disk, the optical disk is tilted left and right. The PCB coil 130 drives the actuator left and right to correct the spot error.

In this case, the tilt driving is performed by the PCB coil 130 on the principle as described with reference to FIGS. 6A and 6B.

As described above, in the present invention, by using a PCB coil having a coil pattern formed inside the PCB instead of a tilt coil in which the existing coil is exposed to the outside, when the actuator is tilted left and right, the winding state of the coil is loosened or the coil is disconnected. And other problems can be prevented.

Although the technical spirit of the present invention has been described in detail according to the above-described preferred embodiment, it should be noted that the above-described embodiment is for the purpose of description and not of limitation. In addition, those skilled in the art will understand that various embodiments are possible within the scope of the technical idea of the present invention.

As described above, the present invention, by tilting the optical pickup actuator using a PCB coil having a coil pattern therein, by compacting the shape of the product to increase the user's preference, and also the coil when the tilt is driven By reducing the probability of breakage, it is possible to improve the accuracy of optical recording and reproduction.

1 is a perspective view of a conventional optical pickup actuator having a three-axis drive function.

FIG. 2 is an exemplary view illustrating a tilt driving principle of the conventional optical pickup actuator shown in FIG.

3 is an external perspective view of an optical pickup actuator using a coil pattern according to an embodiment of the present invention.

Figure 4 is a perspective view of the main portion of the optical pickup actuator using a coil pattern according to an embodiment of the present invention.

Figure 5 is a cross-sectional view of a coil pattern showing an embodiment of a PCB coil provided in the optical pickup actuator of the present invention.

6A and 6B are explanatory diagrams illustrating the tilt driving principle of the PCB coil shown in FIG. 5;

Figure 7a is a front view of a coil pattern showing another embodiment of the PCB coil provided in the optical pickup actuator of the present invention.

7B is a top side view of the coil pattern implemented as in FIG. 7A.

Explanation of symbols on the main parts of the drawings

110: blade 111: objective lens

112: focusing coil 113, 114: first and second tracking coils

115 to 118: first to fourth magnets

120: yoke plate 121, 123, 124: first to third yoke

122: spacer yoke 130: PCB coil

140: wire 150: wire holder

160: FPCB

Claims (8)

An objective lens for focusing light is provided on one side, a focusing coil and first and second tracking coils are installed inside, a first magnet is installed inside the focusing coil, and the first and second tracking coils. A blade provided with a second magnet on an outer side of the blade; A PCB coil mounted to the tilt driving to be spaced apart from the outside of the focusing coil; Third and fourth magnets arranged horizontally on the same plane, spaced apart from the left and right from the center of the blade between the outer side of the focusing coil and the PCB coil to generate a magnetic field for tilt driving; And A first yoke and a spacer yoke for focusing the electric field of the first magnet are formed inside the focusing coil, and a second yoke for focusing the magnetic field of the second magnet is formed outside of the second magnet. And a yoke plate formed outside the PCB coil to focus the magnetic fields of the third and fourth magnets. Actuator for optical pickup comprising a. The method of claim 1, And a first primary side coil pattern and a second secondary side coil pattern having the same shape inside the PCB coil are symmetrically spaced from the left and right sides with respect to the central portion of the blade. The method of claim 2, The actuator for the optical pickup, characterized in that the current in the opposite direction flows on the first secondary coil pattern and the second secondary coil pattern. The method of claim 3, wherein The driving force generated by the primary coil pattern and the secondary coil pattern acts in an upward direction or a downward direction according to the flow of current, but acts in opposite directions to each other. The method of claim 1, And a first primary side coil pattern and a second secondary side coil pattern wound around the PCB coil to have the same number of turns on the first and second magnetic bodies. The method of claim 3, wherein And the first primary coil pattern and the second secondary coil pattern are symmetrically spaced left and right from the center portion of the blade within the PCB coil. The method of claim 6, The actuator for the optical pickup, characterized in that the current in the opposite direction flows on the first and second secondary coil pattern. The method of claim 7, wherein The driving force generated by the primary coil pattern and the secondary coil pattern acts in an upward direction or a downward direction according to the flow of current, but acts in opposite directions to each other.