JP2003045053A - Device for driving objective lens, optical pickup device and optical disk device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress the vibration of a movable part and the temperature rise at a driving coil in operation in a device for driving an objective lens. SOLUTION: Coil part weights 17 are adhered to driving coils 5 and 6 via an adhesive 18 having flexibility even after the adhesion and at least a part of the coil part weights 17 adhered to the driving coils 5 and 6 are exposed to the air.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an objective lens driving device applied to an optical disc drive or a magneto-optical disc drive, an optical pickup device including the objective lens driving device, and an optical disc device including the optical pickup device.

[0002]

2. Description of the Related Art An optical disk apparatus reads information by irradiating a recording surface of an optical disk with a light beam of laser light and identifying the reflected light. The objective lens driving device mounted on the optical disc device uses the control signal obtained from the reflected light to drive the objective lens in the focusing direction and the tracking direction so as to follow the movement of the optical disc such as surface wobbling or eccentricity. Has been done.

In such an optical disk device, in recent years, the recording density has been increased and the recording and reading speeds have been increased, and along with this, elastic deformation of the movable portion (objective lens holding portion) of the objective lens driving device. Is the main factor 10-40
Higher-order resonance near kHz is a serious problem.

When the peak value of high-order resonance increases, the difference (gain margin) between the gain of a certain reference frequency (near the servo crossover frequency) and the peak gain of high-order resonance decreases or becomes negative. .

Here, the gain is a ratio indicating how much the movable part moves with respect to the input voltage (current), and when the gain margin becomes large, strong servo control becomes possible, and the objective lens driving device is driven. The output acceleration can be increased to improve the followability to surface wobbling and eccentricity of the optical disc, and high-speed reading and high-speed writing are possible.

As an example of a conventional objective lens driving device, a device in which the gain margin is increased by lowering the peak of high-order resonance is disclosed in Republished Patent No. 99-1.
0882 publication. This objective lens driving device will be described with reference to FIGS. 13 is a plan view showing the objective lens driving device, FIG. 14 is a side view thereof, and FIG. 15 is a graph showing the relationship between the frequency and the gain of the movable part of the objective lens driving device.

The basic structure of this objective lens driving device is as follows:
It is substantially the same as a general objective lens driving device widely known from the past, and includes a movable portion 101 and a pair of magnet units 1.
02a, 102b, and four leaf springs 103 that elastically support the movable portion 101.

The movable part 101 includes an objective lens 104, a support piece 105 for supporting the objective lens 104, and a support piece 10.
5, a body portion 106 formed integrally with the body 5, a focusing coil 108, a tracking coil 109, and the like attached to a vertical through hole 107 formed in the body portion 106.

The magnet units 102a and 102b include a yoke 110 and a magnet 11 attached and fixed to the yoke 110.
1 and 1.

The balancer weight 11 is provided on the opposite side of the support piece 105 sandwiching the vertical through hole 107 in the main body 106.
2 is fixed or integrally formed. The balancer weight 112 is provided in order to match the position of the center of gravity of the movable portion 101 with the driving force acting point, has a cantilever shape, and its natural frequency is high in the focusing direction of the movable portion 101. The dimensions and weight such as width and length are set so as to substantially match the next resonance frequency, that is, the vibration frequency of the support piece 105 in the focusing direction, and the phase thereof is opposite during vibration.

In this objective lens driving device, during operation, particularly when the support piece 105 vibrates in the focusing direction,
The balancer weight 112 vibrates at the same frequency and in the opposite phase to act as a dynamic damper, thereby canceling the vibration of the support piece 105 and lowering the peak of higher-order resonance.

The graph of FIG. 15 (a) shows the relationship between the frequency and the gain when the vibration of the support piece 105 is canceled by the balancer weight 112 and the peak of high-order resonance is lowered. On the other hand, the graph of FIG. 15B shows the relationship between the frequency and the gain when the balancer weight 112 is completely integrated with the main body 106 and does not function as a dynamic damper.

As shown in the graph of FIG. 15 (b), when the balancer weight 112 does not act as a dynamic damper, the peak of high-order resonance of the movable part 101 is about 2.
It is 9 dB. On the other hand, as shown in the graph of FIG. 15A, when the balancer weight 112 acts as a dynamic damper, the peak of high-order resonance is reduced to about 11 dB.

The gain margin when the reference frequency is 2 kHz is (minus) in the case of FIG. 15B.
15A is larger than that in FIG.

[0015]

However, according to the objective lens driving device described in the above-mentioned Japanese Patent Laid-Open No. 99-10882, the balancer weight 112 is a structure which mainly bends in the focusing direction. It effectively acts as a dynamic damper against the vibration of, but cannot be obtained as a dynamic damper against the vibration in the tracking direction.

Further, in order for the balancer weight 112 to act more effectively as a dynamic damper, it is necessary to devise its shape so that the mass on the tip end side in the cantilever state becomes large, which is complicated. It becomes the shape.

On the other hand, during operation of the objective lens driving device, the focusing coil 108 and the tracking coil 1
When electricity is applied to 09, the focusing coil 108 and the tracking coil 109 generate heat. Due to such heat generation, the focusing coil 108 and the tracking coil 1
When the temperature of 09 increases, the amount of flowing current is suppressed. Then, since the amount of current flowing is suppressed, strong servo control becomes difficult, and it becomes difficult to increase the output acceleration of the objective lens driving device and improve the followability to surface wobbling and eccentricity of the optical disk. Difficult to read and write at high speed.

In this regard, the above-mentioned republished patent 99-
The objective lens driving device described in 10882 and other objective lens driving devices are not provided with a structure for actively radiating heat from the driving coil.

An object of the present invention is to effectively operate a member provided so as to act as a dynamic damper in order to suppress the vibration of the movable portion of the objective lens driving device, and to use the member for the objective lens driving device. Is to effectively dissipate heat from the drive coil during the operation of.

An object of the present invention is to effectively operate a member provided so as to act as a dynamic damper in order to suppress the vibration of the movable portion of the objective lens driving device.

It is an object of the present invention to effectively dissipate heat from the driving coil during operation of the objective lens driving device.

[0022]

The invention according to claim 1 is
A movable part that includes an objective lens that forms a light spot, an objective lens holding member that holds the objective lens, and a driving coil, a fixed member that is fixed to the base, and one end side that is fixed to the movable part. A plurality of rod-shaped elastic support members that elastically support the movable portion with respect to the base by fixing the end side to the fixed member, and the drive coil attached to a yoke provided on the base. In the objective lens driving device including a driving magnet that forms a magnetic circuit together with the yoke by being closely opposed to the coil portion, the coil portion weight is provided via an adhesive having elasticity even after being bonded to the driving coil. It is characterized in that it is attached and at least a part of the coil portion weight is exposed to the atmosphere.

Therefore, when the movable portion vibrates during the operation of the objective lens driving device, the coil weight attached to the driving coil via the adhesive having elasticity even after the adhesion is effective as a dynamic damper. This makes it possible to reduce the peak of higher-order resonance of the movable part, and thereby increase the gain margin. Then, by increasing the gain margin, strong servo control becomes possible, the output acceleration of the objective lens driving device can be increased, and the followability to the surface runout and eccentricity of the optical disc can be improved, and high-speed reading and high-speed writing can be performed. Is possible. On the other hand, since at least a part of the coil weight attached to the drive coil is exposed to the atmosphere, the heat radiation from the drive coil is satisfactorily performed through the coil weight, and the temperature of the drive coil is reduced. The rise is suppressed, and it is prevented that the current flowing through the drive coil is suppressed due to the temperature rise of the drive coil, and a sufficient amount of current can be passed through the drive coil. Then, by supplying a sufficient amount of current to the drive coil, strong servo control becomes possible,
By increasing the output acceleration of the objective lens driving device, it is possible to improve the followability to surface wobbling and eccentricity of the optical disk, and high speed reading and high speed writing are possible.

According to a second aspect of the present invention, there is provided an objective lens for forming a light spot, an objective lens holding member for holding the objective lens, a movable portion provided with a driving coil, and a fixing member fixed to the base. A plurality of rod-shaped elastic supporting members that elastically support the movable portion with respect to the base by fixing one end side to the movable portion and the other end side to the fixing member; An objective lens driving device including a driving magnet that is mounted on a fixed yoke and closely faces the driving coil to form a magnetic circuit together with the yoke, and is elastic even after being bonded to the driving coil. The coil weight is attached via an adhesive having

Therefore, when the movable portion vibrates during the operation of the objective lens driving device, the coil weight attached to the driving coil via the adhesive having elasticity even after the adhesion is effective as a dynamic damper. This makes it possible to reduce the peak of higher-order resonance of the movable part, and thereby increase the gain margin. Then, by increasing the gain margin, strong servo control becomes possible, the output acceleration of the objective lens driving device can be increased, and the followability to the surface runout and eccentricity of the optical disc can be improved, and high-speed reading and high-speed writing can be performed. Is possible.

According to a third aspect of the present invention, there is provided an objective lens for forming a light spot, an objective lens holding member for holding the objective lens, a movable portion provided with a driving coil, and a fixing member fixed to the base. A plurality of rod-shaped elastic supporting members that elastically support the movable portion with respect to the base by fixing one end side to the movable portion and the other end side to the fixing member; A driving magnet that is mounted on a fixed yoke and closely faces the driving coil to form a magnetic circuit together with the yoke, and a coil weight is mounted on the driving coil. At least a part of the coil portion weight is exposed to the atmosphere.

Therefore, since at least a part of the coil weight attached to the drive coil is exposed to the atmosphere, the heat radiation from the drive coil is satisfactorily performed via the coil weight, and the drive coil is driven. The temperature rise of the coil is suppressed, the current flowing through the drive coil due to the temperature rise of the drive coil is prevented from being suppressed, and a sufficient amount of current can be passed through the drive coil. . Then, by supplying a sufficient amount of current to the drive coil, strong servo control becomes possible, the output acceleration of the objective lens drive device can be increased, and the followability to the surface wobbling and eccentricity of the optical disk can be improved. It enables high-speed reading and high-speed writing.

According to a fourth aspect of the present invention, in the objective lens driving device according to the first or second aspect, the thickness dimension of the adhesive is approximately 50 μm or more.

Therefore, the weight of the coil portion easily vibrates, and the function of the dynamic damper can be sufficiently obtained while suppressing the mass of the weight of the coil portion.

The invention according to claim 5 is the invention according to claims 1 to 4.
In the objective lens driving device according to any one of the above, the driving coil is formed in a planar coil shape having a hole in the center, and the coil portion weight is arranged in the hole.

Therefore, there is no need to newly secure a space for installing the coil weight, and the existing space can be effectively used.

According to a sixth aspect of the present invention, in the objective lens driving device according to the first, third or fifth aspect, the weight of the coil portion is attached to the drive coil by using a silicone adhesive. It is characterized by

Therefore, since the silicone-based adhesive has a high thermal conductivity, the heat conduction from the drive coil to the coil weight is excellent, and the heat generated in the drive coil is radiated well from the coil weight. Therefore, the temperature rise of the drive coil is effectively suppressed.

The invention according to claim 7 is the invention as defined in claims 1, 3, and 5.
Alternatively, in the objective lens driving device according to the sixth aspect, the coil portion weight is formed of brass.

Therefore, since brass has a high thermal conductivity,
The heat is favorably conducted from the drive coil to the coil weight, the heat generated in the drive coil is radiated well from the coil weight, and the temperature rise of the drive coil is effectively suppressed.

The invention according to claim 8 is the same as claim 1, 3,
The objective lens driving device described in 5, 6, or 7 is characterized in that a hole portion or an uneven portion is formed in the coil portion weight.

Accordingly, the surface area of the coil weight is increased by forming the hole or the uneven portion in the coil weight, the heat radiation from the coil weight is improved, and the temperature rise of the driving coil is effectively suppressed. .

The invention according to claim 9 is the invention as defined in any one of claims 1 to 8.
In the objective lens driving device described above, the driving magnet is divided into four regions in a cross shape, and the driving magnet is perpendicular to a plane including two axial directions of a focusing direction and a tracking direction. Further, the drive coil is magnetized in the opposite direction to the adjacent region, and the drive coil is positioned on both sides of the magnetic field boundary line in the focusing direction in the vicinity of the surface of the drive magnet, and has magnetic field boundary lines in the tracking direction. Two focusing coils provided straddling, and two focusing coils provided on both sides of the magnetization boundary line in the tracking direction in the vicinity of the surface of the driving magnet and each straddling the magnetization boundary line in the focusing direction. And a tracking coil.

Therefore, also in the objective lens driving device using the magnet of quadrupole magnetization as the driving magnet, the same effects as those described in any one of claims 1 to 8 can be obtained.

An optical pickup device according to a tenth aspect of the present invention includes a laser light source for emitting a laser beam for irradiating the optical disc, an objective lens driving device according to any one of the first to ninth aspects, and an optical disc from the optical disc. A light receiving optical system that receives the reflected light and an objective lens control system that outputs a control signal to the objective lens driving device based on a light receiving signal in the light receiving optical system are provided.

Therefore, this optical pickup device is
Since the objective lens driving device according to any one of claims 1 to 9 is included, the same operation and effect as those described in each of the above-mentioned claims can be obtained, and the output acceleration of the objective lens driving device can be increased to cause the surface wobbling of the optical disk. The followability to eccentricity and eccentricity can be improved, and high-speed reading and high-speed writing are possible.

An optical disk device according to an eleventh aspect of the present invention comprises a rotary drive system for rotationally driving the optical disc, and an optical pickup device according to the ninth aspect, which is provided so as to be movable in the radial direction of the optical disc.

Therefore, since the optical disk device includes the optical pickup device including the objective lens driving device according to any one of claims 1 to 9, the above-mentioned claim 1 is adopted.
The same effects as those described in claims 1 to 9 can be obtained, the output acceleration of the objective lens driving device can be increased, and the followability to the surface runout and eccentricity of the optical disk can be enhanced, and high speed reading and high speed writing are possible. become.

[0044]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows a first embodiment of the present invention.
Or, it demonstrates based on FIG. 1 is a perspective view showing an objective lens driving device, FIG. 2 is a plan view thereof, FIG. 3 is a side view thereof, and FIG. 4 is a front view showing a portion of a tracking coil.

In this objective lens driving device, the objective lens 1 is held by the objective lens holding member 2, and the objective lens holding member 2 is elastically supported by the four wire springs 3 which are rod-shaped elastic supporting members. A vertical through hole 4 is formed in the objective lens holding member 2, and a focusing coil 5, which is a driving coil wound in a tubular shape, is fixed in the vertical through hole 4, and one outer surface of the focusing coil 5 is fixed. Two tracking coils 6, which are drive coils, are fixed to. The tracking coil 6 is formed in a planar coil shape, and a substantially rectangular hole portion 7 is formed in the central portion thereof (see FIG. 4). The objective lens 1, the objective lens holding member 2, the focusing coil 5, the tracking coil 6 and the like constitute a movable portion 8.

Further, the objective lens driving device is provided with a base 9
Is provided, and a pair of yokes 10a and 10b are integrally formed at a substantially central portion of the base 9, and a fixing member 11 is fixed to one end of the base 9.

Driving magnets 12a and 12b forming a magnetic circuit together with the yokes 10a and 10b are fixed to the yokes 10a and 10b.
12b is arranged with a gap so that the magnetic flux penetrates into the drive parts of the focusing coil 5 and the tracking coil 6.

Coil terminal boards 13 are fixed to both sides of the objective lens holding member 2, and one end side of the wire spring 3 is soldered to these coil terminal boards 13. The other end of the wire spring 3 is fixed to the fixing member 11, and the other end of the wire spring 3 is soldered to the substrate 14 attached to the fixing member 11.

In FIG. 3, 15 is an optical disk,
Reference numeral 16 is a rising prism.

A coil weight 17 is mounted in the hole 7 of the tracking coil 6. The coil portion weight 17 is formed of brass, which is a material having good thermal conductivity.

The attachment of the coil weight 17 is performed by using a silicone adhesive 18 which has elasticity and good thermal conductivity even after adhesion. The thickness of the adhesive 18 to which the coil weight 17 is adhered is about 50 μm.
It is set to m or more. The coil portion weight 17 is attached by the adhesive agent 18. The ring-shaped outer peripheral surface of the coil portion weight 17 is adhered to the inner peripheral surface of the hole portion 7, and one surface (back surface) of the coil portion weight 17 is attached to the focusing coil 5. It is performed by adhering to the surface, and the other one surface (surface) of the coil portion weight 17 is exposed to the atmosphere.

In such a structure, by energizing the focusing coil 5 and the tracking coil 6 from the substrate 14 via the wire spring 3 and the coil terminal substrate 13, the movable portion 8 is biaxially moved in the focusing direction and the tracking direction. Can be moved to.

Since the coil weight 17 is attached to the inside of the hole 7 of the tracking coil 6 with the adhesive 18 having elasticity, the coil weight 17 easily vibrates as the movable portion 8 moves. The coil weight 17 serves as a dynamic damper when the movable portion 8 moves. In addition, since the thickness of the adhesive 18 is approximately 50 μm or more, the coil weight 17 is likely to vibrate, and the mass of the coil weight 17 can be suppressed to be small, and a sufficient action as a dynamic damper can be obtained. As a result, the peak of higher-order resonance of the movable portion 8 can be lowered and the gain margin can be increased. Then, since the gain margin becomes large, strong servo control becomes possible, the output acceleration of the objective lens driving device can be increased, and the followability with respect to surface wobbling and eccentricity of the optical disk 15 can be enhanced, and high-speed reading and high-speed reading can be achieved. Writing is possible.

Moreover, since the coil weight 17 can vibrate in both the focusing direction and the tracking direction, it is effective as a dynamic damper against movement in both the focusing direction and the tracking direction. Act on.

Further, as a structure for lowering the peak of higher-order resonance of the movable part 8, the hole 7 of the tracking coil 6 is formed.
The coil weight 17 is simply attached to the inside with the adhesive 18, and the shape of the coil weight 17 does not need to be specially devised, and a simple structure can be obtained. Moreover, there is no need to newly secure a space for installing the coil weight 17, and the existing space can be effectively used.

Further, since the coil weight 17 is adhered by the silicone adhesive 18 having good heat conductivity and is made of brass which is a material having good heat conductivity,
The heat generated in the focusing coil 5 and the tracking coil 6 can be efficiently transmitted to the coil weight 17. Further, since the surface of the coil portion weight 17 is exposed to the atmosphere, the heat transferred to the coil portion weight 17 can be efficiently radiated from the surface of the coil portion weight 17 to the atmosphere, and the focusing coil 5 and the tracking coil 5 can be tracked. The temperature rise of the coil 6 can be prevented.
Note that the heat radiation effect of the coil weight 17 is particularly effectively obtained in the tracking coil 6 which originally has a small surface area and cannot easily radiate heat.

In this way, since the heat radiation from the focusing coil 5 and the tracking coil 6 can be effectively performed, the focusing coil 5 and the tracking coil 6
It is prevented that the temperature rises due to energization and the current flowing through the focusing coil 5 and the tracking coil 6 is suppressed, and a sufficient amount of current can flow through the focusing coil 5 and the tracking coil 6. Then, by supplying a sufficient amount of current to the focusing coil 5 and the tracking coil 6, strong servo control becomes possible, and the output acceleration of the objective lens driving device is increased to follow the surface wobbling and eccentricity of the optical disk 15. It is possible to increase the read speed and write speed.

In this embodiment, the case where the coil portion weight 17 is arranged in the hole portion 7 of the tracking coil 6 and adhered has been described as an example, but it is attached to the surface portion of the tracking coil 6. Alternatively, as shown in FIG. 5 as a modification of the present embodiment, the coil weight 17a may be adhered to the surface of the focusing coil 5 with the adhesive 18. In this case, the adhesive 18
Has a thickness of approximately 50 μm or more.

In the present embodiment, the objective lens driving device having a structure (objective lens offset type) in which the objective lens 1 is arranged at the end of the movable portion 8 has been described as an example, but the objective lens is a focusing coil. The present invention can also be applied to an objective lens driving device having a structure (objective lens center type) arranged in a substantially central portion of a region where a tracking coil, a driving magnet, and the like are arranged.

Next, a second embodiment of the present invention will be described with reference to FIG.
It will be described based on. The same parts as those described with reference to FIGS. 1 to 5 are designated by the same reference numerals, and the description thereof will be omitted (the same applies to the following embodiments).

The basic structure of this embodiment is the same as that of the modification shown in FIG. 5, and the coil portion weight 17b is adhered to the surface of the focusing coil 5, and this adhesion is made of silicon having elasticity even after adhesion. The adhesive 18 of the system is used. In this case, the thickness of the adhesive 18 is about 50 μm or more.

The difference of the present embodiment from the modification shown in FIG. 5 is that a plurality of holes 19 are formed in the coil weight 17b.
Is formed.

With such a structure, by forming the plurality of holes 19 in the coil weight 17b, the surface area of the coil weight 17b is increased, and the heat radiation from the coil weight 17b can be improved.

Next, a third embodiment of the present invention will be described with reference to FIG.
It will be described based on. The basic structure of this embodiment is shown in FIG.
6 is the same as the embodiment shown in FIG.
The difference from the embodiment shown in FIG. 6 is that a plurality of convex portions 20 that are concave and convex portions are formed instead of the hole portions 19 in order to increase the surface area of the coil portion weight 17c.

In such a structure, by forming such a convex portion 20 on the coil weight 17c,
The surface area of the coil weight 17c is increased, and the heat dissipation from the coil weight 17c can be improved.

Next, a fourth embodiment of the present invention will be described with reference to FIG.
And it demonstrates based on FIG. In this objective driving lens device, driving magnets 21a and 21b divided into four in a cross shape are fixed to the yokes 10a and 10b. Driving coils (focusing coil 22 and tracking coil 23) arranged at positions facing the driving magnets 21a and 21b and fixed to the objective lens holding member 2.
Are both formed in a planar coil shape.

The drive magnets 21a and 21b are magnetized in four divisions with the cross-shaped magnetizing boundaries a and b as boundaries (quadrupole magnetizing), and the magnetizing direction is the focusing direction (Y axis). Direction) and a tracking direction (X-axis direction), which is perpendicular to the plane including the biaxial direction (Z-axis direction) and opposite to the adjacent region. Further, the driving magnet 21
The a and 21b are arranged such that the magnetizing directions of the portions facing each other with the focusing coil 22 and the tracking coil 23 in between are aligned.

A brass coil weight 17d is arranged in the hole 7 of the tracking coil 23, and is bonded using a silicon adhesive 18 having elasticity even after bonding. The surface of the coil portion weight 17d (the surface facing the magnet 21a) is exposed to the atmosphere. The back surface (the surface facing the focusing coil 22) of the coil portion weight 17d is bonded to the focusing coil 22 with an adhesive 18. In this case, the thickness of the adhesive 18 is approximately 50 μm or more at each bonding location.

With such a configuration, the objective lens driving device using the quadrupole magnetized driving magnets 21a and 21b also has the same effects as those described in the above-described embodiments.

That is, the silicon-based adhesive 18 having elasticity even after being bonded to the hole 7 of the tracking coil 23.
By mounting the coil portion weight 17d by using, the coil portion weight 17d acts as a dynamic damper, and the peak of high-order resonance can be lowered.

The coil weight 17d is attached by using a silicone adhesive 18 having good thermal conductivity, and the surface of the coil weight 17d is exposed to the atmosphere. The heat generated by the focusing coil 22 and the heat generated by the tracking coil 23, particularly the heat generated by the tracking coil 23, can be efficiently transferred to the coil weight 1.
The heat transmitted to the coil weight 17d can be radiated from the surface thereof. As a result, it is possible to suppress an increase in the temperature of the tracking coil 23 and the focusing coil 22 during operation and allow a large amount of current to flow through the tracking coil 23 and the focusing coil 22.

Next, a fifth embodiment of the present invention will be described with reference to FIG.
A description will be given based on 0. The present embodiment shows an application example to an optical pickup device 32 provided with an objective lens driving device 31 configured as in each of the above-described embodiments. The diffused light emitted from the laser light source 33 such as a semiconductor laser mounted on the optical pickup device 32 is converted into substantially parallel light by the collimator lens 34. After that, it passes through the beam splitter 35 and is bent by the rising mirror 16. The parallel light bent by the rising mirror 16 enters the objective lens 1 of the objective lens driving device 31 mounted on the optical pickup device 32 and forms a spot on the optical disc 15.

The light reflected from the spot is reflected by the beam splitter 35.
After passing through the condenser lens 37 and the cylindrical lens 38, the light enters the four-division light receiving element 39. The above-mentioned optical components are arranged so that the reflected light of the spot on the optical disk 15 enters the four-division light receiving element 39. Focusing coil and tracking coils 5 and 6 (or 22, 23) of the objective lens driving device 31 based on the signal obtained by the four-division light receiving element 39.
The information of the optical disc 15 can be obtained by energizing the optical disc 15 and causing the objective lens 1 to follow the optical disc 15. Condensing lens 37, cylindrical lenses 38 and 4
The split light receiving element 39 constitutes a light receiving optical system 40. Further, an objective lens control system (not shown) that outputs a drive signal to the objective lens drive device 31 based on the light reception signal of the four-division light receiving element 39 is also provided.

In such a structure, the objective lens driving device 31 mounted on the optical pickup device 32 is
The objective lens driving device 31 is configured as described in the above-described first to fourth embodiments, and as described above.
The objective lens 1 can be made to follow the optical disc 15 to read information from the optical disc 15 or write information to the optical disc 15. Moreover, in the objective lens driving device 31, the peak of the high-order resonance of the movable portion 8 is made small and the gain margin is made large. Further, the heat radiation from the focusing coil and the tracking coil is favorably performed, and the temperature rises. Since it is suppressed, strong servo control becomes possible, the output acceleration of the objective lens driving device 31 can be increased, and the followability to the surface wobbling and eccentricity of the optical disk 15 can be enhanced, and high speed reading and high speed writing are possible. Become.

Next, a sixth embodiment of the present invention will be described with reference to FIG.
1 and FIG. 12 will be described. The present embodiment shows an application example to an optical disc drive (optical disc device) equipped with the optical pickup device 32 as described above. First, the pickup module base 43 is installed in the housing 41 of the optical disk drive via the anti-vibration rubber 42. A spindle motor 44 as a rotary drive system for rotating the optical disk 15 is fixed to the pickup module base 43. An optical pickup device 32 is mounted on the seek rail 45 attached to the pickup module base 43. The optical pickup device 32 is movable on the seek rail 45 in the radial direction (radial direction) of the optical disk 15.

Here, in the optical pickup device 32 mounted on the optical disk drive, the peak of the high-order resonance of the movable portion 8 is reduced and the gain margin is increased, as described in the fifth embodiment. Has been made bigger,
Further, since the heat radiation from the focusing coil and the tracking coil is favorably performed and the temperature rise is suppressed, strong servo control becomes possible, and the output acceleration of the objective lens driving device 31 is increased to cause the surface deflection of the optical disc 15. The followability to eccentricity can be improved, and high-speed reading and high-speed writing are possible.

[0077]

According to the objective lens driving device of the first aspect of the present invention, when the movable portion vibrates during operation of the objective lens driving device, the driving coil is provided through the adhesive having elasticity even after the bonding. The coil weight attached to the coil effectively acts as a dynamic damper to reduce the peak of high-order resonance of the movable part, which can increase the gain margin and increase the gain margin. As a result, strong servo control can be performed, the output acceleration of the objective lens driving device can be increased, and the followability to surface wobbling and eccentricity of the optical disk can be enhanced, and high-speed reading and high-speed writing are possible. Furthermore, since at least a part of the coil weight attached to the drive coil is exposed to the atmosphere, heat radiation from the drive coil can be satisfactorily performed via the coil weight. The temperature rise of the drive coil can be suppressed. Therefore, it is possible to prevent the current flowing through the drive coil from being suppressed due to the temperature rise of the drive coil, and to prevent the drive coil from having a sufficient temperature. A large amount of current can be passed, and by supplying a sufficient amount of current to the drive coil, strong servo control becomes possible, and the output acceleration of the objective lens drive device can be increased to prevent surface runout and eccentricity of the optical disc. The followability can be enhanced, and high-speed reading and high-speed writing are possible.

According to the objective lens driving device of the second aspect, when the movable portion vibrates during the operation of the objective lens driving device, the objective lens driving device is attached to the driving coil through the adhesive having elasticity even after the bonding. The coil part weight that is effectively operated can reduce the peak of higher-order resonance of the movable part by effectively acting as a dynamic damper, thereby increasing the gain margin and increasing the gain margin. Strong servo control becomes possible, the output acceleration of the objective lens driving device can be increased, and the followability to the surface runout and eccentricity of the optical disk can be enhanced, and high speed reading and high speed writing are possible.

According to the objective lens driving device of the third aspect of the present invention, at least a part of the coil weight attached to the driving coil is exposed to the atmosphere, so that the heat radiation from the driving coil is prevented. It can be satisfactorily carried out via the coil weight, which can suppress the temperature rise of the driving coil, and therefore the current flowing through the driving coil as the temperature of the driving coil rises. Can be prevented and a sufficient amount of current can be supplied to the drive coil. By supplying a sufficient amount of current to the drive coil, strong servo control becomes possible and the objective lens drive The output acceleration of the device can be increased to improve the followability to surface wobbling and eccentricity of the optical disc, and high-speed reading and high-speed writing are possible.

According to the invention described in claim 4, in the objective lens driving device according to claim 1 or 2, since the thickness of the adhesive is approximately 50 μm or more, the coil weight easily vibrates, The function as a dynamic damper can be sufficiently obtained while suppressing the mass of the partial weight to be small.

According to a fifth aspect of the present invention, in the objective lens driving device according to any one of the first to fourth aspects, the driving coil is formed in the shape of a plane coil having a hole in the center, and the inside of the hole is formed. Since the coil portion weight is disposed in the above, it is not necessary to newly secure a space for installing the coil portion weight, and the existing space can be effectively used.

According to the invention of claim 6, claim 1,
In the objective lens driving device described in 3 or 5, since the attachment of the coil weight to the driving coil is performed by using a silicone adhesive, the silicone adhesive has a high thermal conductivity, The heat conduction from the working coil to the coil weight can be favorably performed, and the heat generated in the driving coil can be radiated well from the coil weight, so that the temperature rise of the driving coil can be effectively suppressed.

According to the invention of claim 7, claim 1,
In the objective lens driving device described in item 3, 5 or 6, since the coil weight is made of brass, the brass has a high thermal conductivity, and heat conduction from the driving coil to the coil weight is excellent. Therefore, the heat generated in the driving coil can be radiated well from the coil weight, and the temperature rise of the driving coil can be effectively suppressed.

According to the invention of claim 8, claim 1,
In the objective lens driving device described in 3, 5, 6 or 7,
Since the coil portion weight has holes or uneven portions, it is possible to increase the surface area of the coil portion weight by forming these holes or uneven portions to enhance heat dissipation from the coil portion weight. Therefore, the temperature rise of the drive coil can be effectively suppressed.

According to the ninth aspect of the present invention, in the objective lens driving device according to any one of the first to eighth aspects, the case where a quadrupole magnetized magnet is used as the driving magnet has been described above. The same effects as those described in any one of claims 1 to 8 can be obtained, strong servo control can be performed, and output acceleration of the objective lens driving device can be increased to deal with surface wobbling or eccentricity of the optical disk. The followability can be improved, and high-speed reading and high-speed writing are possible.

According to the optical pickup device of the tenth aspect of the present invention, since the optical pickup device includes the objective lens driving device of any one of the first to ninth aspects,
The same effects as those described in each of the above-mentioned claims can be obtained, strong servo control can be performed, the output acceleration of the objective lens driving device can be increased, and the followability to the surface wobbling and eccentricity of the optical disk can be improved. It enables high-speed reading and high-speed writing.

According to the optical disk device of the invention described in claim 11, the optical disk device includes an optical pickup device including the objective lens driving device according to any one of claims 1 to 9. The same effects as those described in claims 1 to 9 can be obtained, strong servo control can be performed, output acceleration of the objective lens driving device can be increased, and followability to surface wobbling and eccentricity of the optical disk can be improved. Therefore, high-speed reading and high-speed writing are possible.

[Brief description of drawings]

FIG. 1 is a perspective view showing an objective lens driving device according to a first embodiment of the present invention.

FIG. 2 is a plan view thereof.

FIG. 3 is a side view thereof.

FIG. 4 is a front view showing a portion of a tracking coil.

FIG. 5 is a perspective view showing a modified example.

FIG. 6 is a perspective view showing a movable part in an objective lens driving device according to a second embodiment of the present invention.

FIG. 7 is a perspective view showing a movable part in an objective lens driving device according to a third embodiment of the present invention.

FIG. 8 is a perspective view showing an objective lens driving device according to a fourth embodiment of the present invention.

FIG. 9 is an exploded perspective view showing an arrangement state of a drive coil and a drive magnet that are a part thereof.

FIG. 10 is a schematic configuration diagram showing an optical pickup device according to a fifth embodiment of the present invention.

FIG. 11 is a schematic plan view showing an optical disc drive according to a sixth embodiment of the present invention.

FIG. 12 is a side view thereof.

FIG. 13 is a plan view showing a conventional objective lens driving device.

FIG. 14 is a side view thereof.

FIG. 15 is a graph showing the relationship between the frequency and vibration intensity of the movable part of the objective lens driving device.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Objective lens 2 Objective lens holding member 3 Rod-shaped elastic support members 5 and 6 Driving coil 7 Hole 8 Movable part 9 Bases 10a and 10b Yoke 11 Fixing members 12a and 12b Driving magnet 15 Optical disk 17, 17a, 17b, 17c , 17d Coil part weight 18 Adhesive 19 Hole 20 Concavo-convex part 22 and 23 Driving coil 31 Objective lens driving device 32 Optical pickup device 33 Laser light source 40 Light receiving optical system 44 Rotational driving system

Claims (11)

[Claims] 1. A movable part having an objective lens for forming a light spot, an objective lens holding member for holding the objective lens, and a drive coil, a fixed member fixed to a base, and one end side of the movable part. A plurality of rod-shaped elastic supporting members that elastically support the movable portion with respect to the base by being fixed to the fixing member and the other end side being fixed to the fixing member, and attached to a yoke provided on the base. And a driving magnet that forms a magnetic circuit together with the yoke by being closely faced to the driving coil by an adhesive agent having elasticity even after being bonded to the driving coil. An objective lens driving device, wherein a coil portion weight is attached, and at least a part of the coil portion weight is exposed to the atmosphere. 2. A movable part having an objective lens for forming a light spot, an objective lens holding member for holding the objective lens, and a driving coil, a fixed member fixed to a base, and one end side of the movable part. A plurality of rod-shaped elastic supporting members that elastically support the movable portion with respect to the base by being fixed to the fixing member and the other end side being fixed to the fixing member, and attached to a yoke provided on the base. And a driving magnet that forms a magnetic circuit together with the yoke by being closely faced to the driving coil by an adhesive agent having elasticity even after being bonded to the driving coil. The objective lens driving device is characterized in that a coil portion weight is attached. 3. A movable part having an objective lens for forming a light spot, an objective lens holding member for holding the objective lens, and a driving coil, a fixed member fixed to a base, and one end side of the movable part. A plurality of rod-shaped elastic support members that are elastically supported on the base by fixing the other end side to the fixing member, and are attached to a yoke provided on the base. And a driving magnet that forms a magnetic circuit together with the yoke by being closely opposed to the driving coil, the coil weight is attached to the driving coil, and the coil weight is attached to the driving coil. An objective lens driving device, characterized in that at least a part of it is exposed to the atmosphere. 4. The objective lens driving device according to claim 1, wherein the thickness of the adhesive is approximately 50 μm or more. 5. The driving coil is formed into a planar coil shape having a hole in the center, and the coil portion weight is arranged in the hole. The described objective lens drive device. 6. The objective lens driving device according to claim 1, wherein the weight of the coil portion is attached to the driving coil by using a silicone adhesive. 7. The weight of the coil portion is made of brass.
The described objective lens drive device. 8. The coil portion weight is formed with a hole portion or a concave-convex portion,
5. The objective lens driving device according to 5, 6, or 7. 9. The driving magnet is divided into four regions in a cross shape in the surface of the drive magnet, and is perpendicular to a plane including the biaxial directions of the focusing direction and the tracking direction and in a direction opposite to an adjacent region. The driving coil is magnetized, and two focusing coils are provided on both sides of a magnetization boundary line in the focusing direction in the vicinity of the surface of the drive magnet, and the two focusing coils are provided across the magnetization boundary line in the tracking direction. A coil and two tracking coils located on both sides of the magnetizing boundary line in the tracking direction near the surface of the driving magnet and provided across the magnetizing boundary line in the focusing direction. The driving apparatus for an objective lens according to claim 1, wherein 10. A laser light source that emits laser light for irradiating an optical disc, an objective lens driving device according to claim 1, and a light receiving optical system that receives reflected light from the optical disc. And an objective lens control system that outputs a control signal to the objective lens driving device based on a light reception signal in the light receiving optical system. 11. An optical disc apparatus comprising: a rotary drive system for rotationally driving an optical disc; and an optical pickup device according to claim 10, which is provided so as to be movable in a radial direction of the optical disc.