JP2006172552A - Optical head and optical disk device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical head to reduce an amount of an adhesive at the time of attaching a focusing coil to a lens holder and manufacture roundness or the like of a shaft hole for a shaft to penertrate through with high accuracy, and to raise accuracy of focusing operation and tracking operation all the more. <P>SOLUTION: The optical head comprises a coil holding part 215 projecting from the lens holding part 211, a cylindrical shaft hole 212, and a magnetic plate 216 adhesively fixed to the coil holding part 211, and four corner parts of the coil holding part 215 on which the focusing coil 214 is engaged are notched, and adhesive injection parts 217 are formed. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

The present invention relates to an optical disc apparatus capable of recording and / or reading data by irradiating an optical disc with laser light, and more particularly to an optical head for irradiating the optical disc with laser light.

2. Description of the Related Art Optical discs that can record and / or read information by irradiating a laser beam are used as recording media for information such as video and audio. As the optical disc, a CD (Compact Disc), a DVD (Digital Versatile Disc) and the like are widely used. An optical disc apparatus that records data on and / or reads data from the optical disc using these optical discs as a recording medium has recorded or reflected data by irradiating the recording surface of the optical disc with laser light. An optical head for reading data by detecting light is provided.

FIG. 2 shows the layout of the optical head. The optical head shown in FIG. 2 is not limited to this, but here is a read-only optical head for reading data recorded on an optical disk. As shown in FIG. 2, it has a laser light source Ld, a mirror Mr, a collimator lens 3, an objective lens 4, a beam splitter Bs, and a light receiving element Pd. The laser light emitted from the laser light source Ld is reflected by the mirror Mr and enters the collimator lens 3. The laser light incident on the collimator lens 3 is emitted as parallel light and enters the objective lens 4. The laser light incident on the objective lens 4 is applied to the recording surface of the optical disc Ds. The objective lens 4 is an actuator 9
2 is arranged.

At this time, the laser beam is irradiated with the laser beam so that the recording layer of the optical disc Ds is focused and the optical axis is perpendicular to the recording layer of the optical disc Ds. The beam splitter Bs is a prism that transmits half of the incident laser light and reflects the half, and guides the light reflected by the optical disk Ds to the light receiving element Pd. The light receiving element Pd converts light into current,
Data is read by the intensity of light. An optical head capable of recording data on an optical disc has basically the same configuration.

The optical disk Ds is caused by the fluctuation of the disk surface, the eccentricity of the optical disk Ds, etc.
Surface blurring or radial blurring of the disk surface of s with respect to the horizontal plane occurs. When surface blurring and radial blurring occur, the focus of the light spot obtained by condensing the laser light emitted from the objective lens 4 is not focused on the recording surface of the optical disc Ds, or the track on the recording surface is not accurately irradiated. May occur. When the above problems occur, when the light spot is not irradiated at an accurate position, data is not read from or recorded on the optical disk Ds, and the sound being reproduced is interrupted or data is read. Or a recording error occurs.

Therefore, the objective lens 4 is moved (focused) in the focus direction perpendicular to the recording surface of the optical disc Ds so that the focal point of the optical spot matches the recording surface of the optical disc Ds according to the amount of surface blur of the optical disc Ds. The optical spot is moved (tracked) as necessary in the tracking direction, which is the radial direction, so that the light spot of the optical disc Ds is accurately irradiated to the track on the recording surface.

FIG. 10 is a plan view showing an example of a conventional optical head actuator. The actuator 92 shown in FIG. 10 includes the objective lens 4, a lens holder 93 that holds the objective lens 4, a case 94 that supports the lens holder 93, and a substrate 95 that supplies electric power.

FIG. 11 shows a bottom view of the lens holder shown in FIG. The lens holder 93 includes a lens holding portion 931 that holds the objective lens 4, a shaft hole 932 that is slidably and rotatably fitted on a shaft 943 (described later) provided in the case 94, and an outer wall of the shaft hole 932. A rib 933 for supporting a plurality (four in this case) of shaft holes 932 extending from the main body of the lens holder 93, and a tracking coil 934 for swinging the lens holder 93 about the shaft 943 in the lens holder 93. Then, a focusing coil 935 for sliding the lens holder 93 along the shaft 943 and a magnetic plate 936 through which the shaft hole 932 passes through the center are attached.

The focusing coil 935 is disposed so as to surround the periphery of the shaft hole 932, and is wound in a rectangular shape so that the ends of the ribs 933 form four corners. When fixing the focusing coil 935 disposed on the rib 933 to the lens holder 93, an adhesive (not limited thereto) is used for the portion 930 surrounded by the focusing coil 935, the rib 933, and the outer wall of the shaft hole 932. A thermosetting adhesive) is injected. Thereafter, a magnetic plate 936 is disposed so as to be in contact with the focusing coil 935, and an adhesive is further injected and heated to be cured. In addition to fixing the focusing coil 935 and the magnetic plate 936, the adhesive can also increase the strength around the shaft hole 932.

The case 94 has a rectangular bottom surface 941 in plan view, a rising wall 942 rising from four sides of the bottom surface 941, a shaft 943 protruding from the bottom 941 toward the inside of the case 94,
And a permanent magnet 944 arranged to face the rising wall 942 with the shaft 943 interposed therebetween. The shaft 943 is made of a magnetic material. Permanent magnet 944 and shaft 943
A magnetic field is generated between them.

The shaft 943 of the case 94 is disposed inside the case 94 so as to fit the shaft hole 932 of the lens holder 93 so as to be rotatable and slidable. At this time, the permanent magnet 944 and the shaft 94
3, the magnetic plate 936 of the lens holder 93 is disposed in the magnetic field generated between the three. Magnetic plate 936
Is placed in the magnetic field, so that a magnetic force is applied to the magnetic plate 936. The lens holder 93 is supported by the magnetic force applied to the magnetic plate 936 without contacting the bottom surface 941 of the case 94.

In addition, a tracking coil 934 and a focusing coil 935 are disposed in the magnetic field between the permanent magnet 944 and the shaft 943. When a current is passed through the tracking coil 934, Lorentz force is generated in the tracking coil 934. By this Lorentz force, the lens holder 93 is swung around the shaft 943. Further, a Lorentz force is generated in the focusing coil 935 by causing a current to flow through the focusing coil 935. The lens holder 93 slides in the axial direction of the shaft 943 by this Lorentz force.

Since the shaft hole 932 is externally fitted to the shaft 943 and rotates (tracking) and / or slides (focusing), the shaft hole 93 is used to keep the tracking and focusing operations highly accurate.
It is necessary to manufacture so as to increase the inner circumference accuracy of 2. The invention described in Japanese Patent Application Laid-Open No. 2003-248944 adjusts the thickness of the wall of the shaft hole to suppress the occurrence of defects such as sink holes and welds in the shaft hole during integral molding. In the invention described in Japanese Patent Laid-Open No. 10-143888, at least two sliding gap setting members are provided in the shaft hole to reduce the sliding resistance of the sliding surface.
JP 2003-248944 A Japanese Patent Laid-Open No. 10-143888

In the case where the focusing coil 935 is disposed around the shaft hole 932 and the adhesive is injected and bonded, the strength of the shaft hole 932 is secured by the adhesive, and thus a large amount of the adhesive is injected and the adhesive Shrinks considerably when cured. The shaft hole 932 is formed by the curing and shrinkage of the adhesive.
In addition, stress is applied to the focusing coil 935.

The shaft hole 932 and the focusing coil 935 are deformed by the stress when the adhesive is cured. At this time, since the injection amount of the adhesive is large, it is not uniformly cured but is cured non-uniformly. Due to this uneven curing of the adhesive, the stress at the time of curing the adhesive applied to the shaft hole 932 is also uneven and the accuracy such as roundness is lowered. When the accuracy of the shaft hole 932 decreases, the lens holder 9
When 3 is disposed in the case 94, the friction between the shaft hole 932 and the shaft 943 increases or the backlash occurs, and the accuracy of the tracking operation and the focusing operation decreases.

The invention described in Japanese Patent Laid-Open No. 2003-248944 and Japanese Patent Laid-Open No. 10-143888 solves the problem of a decrease in accuracy of the shaft hole due to stress generated by the curing of the adhesive when the focusing coil is attached to the lens holder. I can't.

Further, since a large amount of adhesive is used, the weight of the lens holder 93 is increased. As described above, the lens holder 93 is a movable part that performs the tracking operation and the focusing operation, and a large driving force is required when the tracking operation and the focusing operation are performed due to an increase in the weight of the movable part. In order to generate a large driving force in the tracking coil 934 and the focusing coil 935, the magnetic flux density generated by the permanent magnet is increased, the current flowing through the tracking coil 934 and the focusing coil 935 is increased, or the tracking coil 934 and the focusing coil The number of 935 turns must be increased. In either case, a large amount of energy is required for manufacturing or driving, and the cost required for manufacturing and driving increases.

Therefore, the present invention can reduce the amount of adhesive when attaching the focusing coil to the lens holder, and can be manufactured with high accuracy such as the roundness of the shaft hole through which the shaft passes,
Accordingly, an object of the present invention is to provide an optical head and an optical disk device using the optical head that can improve the accuracy of the focusing operation and the tracking operation.

In addition, the present invention reduces the amount of adhesive when attaching the focusing coil to the lens holder, and can reduce the weight while maintaining the strength of the lens holder, thereby reducing the energy required for manufacturing and operating the lens holder. It is an object of the present invention to provide an optical head and an optical disk device using the optical head.

In order to achieve the above object, the present invention provides a spindle motor that rotates an optical disk, an optical head that irradiates the optical disk with laser light, a signal processing device that processes signals, and a detection by the optical head. An optical disk device comprising an external connection unit for connecting a signal decoded by the signal processing device to an external video display unit, and a control unit, wherein the optical head is a laser that irradiates laser light A light source, a mirror that reflects the laser beam, a collimator lens that collimates the laser beam, an objective lens for irradiating the optical disc with the laser beam, and a beam splitter that splits the light reflected by the optical disc A light receiving element that receives light and converts it into an electrical signal, and an actuator that drives the objective lens, A lens holder that holds the lens; a case in which the lens holder is disposed; and a wiring board that is attached to the case and the lens holder and supplies electric power. A rising portion that protrudes perpendicularly to the bottom portion from the end portion, a cylindrical shaft that protrudes in the same direction as the rising portion at a substantially central portion of the bottom portion, and the shaft that is disposed with the shaft sandwiched between the rising portions. The lens holder includes a lens holding portion that holds the objective lens, and a column that protrudes from a substantially center of the lens holding portion and has a substantially rectangular cross section. And a cylindrical shaft hole that penetrates the lens holding portion and the coil holding portion and is fitted to the shaft so as to be rotatable and slidable. A magnetic plate that is bonded and fixed to the opposite side of the lens holding portion of the coil holding portion, a tracking coil that is opposed and fixed to a side surface of the lens holding portion across the shaft hole, and the coil holding portion A focusing coil that is externally fitted and fixed by adhesion, and four corners of the coil holding portion to which the focusing coil is externally fitted are cut to form an adhesive injection portion, Provided is an optical disc apparatus characterized in that the focusing coil is fixed to the coil holding part by injecting an adhesive into the adhesive injection part and curing it.

According to this configuration, since the coil holder of the lens holder is solid, the weight of the lens holder alone increases, but the amount of adhesive used to fix the focusing coil is greatly reduced. Therefore, the weight can be reduced with the focusing coil attached.

Since the lens holder can be reduced in weight, a quick and smooth operation is possible during a tracking operation and a focusing operation. Further, the energy required for the operation is small, in other words, the power supplied to the tracking coil and the focusing coil may be small, and energy saving can be achieved. Furthermore, the force required for driving may be small,
Accordingly, smaller coils can be adopted as the tracking coil and the focusing coil, and the cost can be reduced accordingly.

Further, since the amount of the adhesive used for the focusing coil is small, the volume change during curing is small, and the stress generated during curing is small accordingly. Furthermore, since the lens holder is formed in a solid shape, the thickness from the outer surface to the inner surface of the shaft hole is large, and the lens holder has a high strength, so that the stress generated when the adhesive is cured Difficult to deform.

Since the shaft hole is not easily deformed by the stress generated when the adhesive is cured, the roundness of the shaft hole can be increased. Thus, the friction characteristics between the shaft and the shaft hole can be optimized, and the tracking operation and the focusing operation can be performed smoothly.

In order to achieve the above object, the present invention provides a spindle motor that rotates an optical disk, an optical head that irradiates the optical disk with laser light, a signal processing device that processes signals, and a detection by the optical head. An optical disk device comprising an external connection unit for connecting a signal decoded by the signal processing device to an external video display unit, and a control unit, wherein the optical head emits a laser beam. A mirror that reflects the laser beam, a collimator lens that collimates the laser beam, an objective lens that irradiates the optical disc with the laser beam, and a beam splitter that splits the light reflected by the optical disc; A light receiving element that receives light and converts it into an electrical signal, and an actuator that drives the objective lens,
The actuator includes a lens holder that holds the objective lens, a case in which the lens holder is disposed, and a wiring board that is attached to the case and the lens holder and supplies electric power. A rising portion that protrudes perpendicularly to the bottom portion from the end of the bottom portion, a cylindrical shaft that protrudes in the same direction as the rising portion at the approximate center of the bottom portion, and the shaft is sandwiched between the rising portions. And two permanent magnets that form a magnetic field between the shaft and the shaft, and the lens holder is formed at a lens holding portion for holding the objective lens, and substantially at the center of the lens holding portion. A coil holding portion having a rectangular through hole and a wall portion formed so as to surround the through hole, and the rectangular through hole and the coil holding portion A cylindrical shaft hole that is arranged in a central space and can be fitted to the shaft so as to be able to rotate and make a noise, and the shaft is connected to the four corners of the wall portion and connected to the cylindrical shaft hole. A rib portion for fixing a hole; a magnetic plate that is bonded and fixed to the opposite side of the coil holding portion to the lens holding portion; a tracking coil that is bonded and fixed to a side surface of the lens holding portion; An optical disc apparatus comprising: a focusing coil that is fitted and fixed by adhesion, wherein the focusing coil is fitted on the coil holding portion to install and fix the focusing coil on the coil holding portion. provide.

According to this configuration, since the coil holding portion penetrates the lens holder in a rectangular shape, the weight of the lens holder can be reduced. Further, since the focusing coil is not bonded and fixed with an adhesive, it is possible to reduce the weight even when the focusing coil is attached.

Since the lens holder can be reduced in weight, a quick and smooth operation is possible during a tracking operation and a focusing operation. Further, the energy required for the operation is small, in other words, the power supplied to the tracking coil and the focusing coil may be small, and energy saving can be achieved. Furthermore, the force required for driving may be small,
Accordingly, smaller coils can be adopted as the tracking coil and the focusing coil, and the cost can be reduced accordingly.

The lens holder may not have a rectangular through hole. In this case, the wall surface portion connected in a rectangular shape from the lens holding portion and the cylindrical shaft hole protrude from the lens holding portion.

In order to achieve the above object, the present invention provides a bottom portion, a rising portion that protrudes perpendicularly to the bottom portion from an end portion of the bottom portion, and a columnar shape that protrudes in the same direction as the rising portion at a substantially center of the bottom portion. , A case having two permanent magnets that are arranged with the shaft sandwiched between the rising portions and that form a magnetic field between the shaft, a lens holding unit that holds an objective lens, and the lens holding unit A column-shaped coil holding portion that protrudes from the approximate center of and has a substantially rectangular cross section;
A cylindrical shaft hole that protrudes from substantially the center of the coil holding portion and penetrates the lens holding portion and the coil holding portion and is fitted to the shaft so as to be rotatable and slidable, and the lens of the coil holding portion A magnetic plate that is bonded and fixed to the opposite side of the holding unit, a tracking coil that is bonded and fixed to the side surface of the lens holding unit, facing the shaft hole, and is externally fitted and fixed to the coil holding unit. A lens holder having a focusing coil and a wiring board attached to the case and the lens holder and supplying power to the tracking coil and the focusing coil, and the focusing coil of the coil holding portion is Four corners to be fitted are cut off to form an adhesive injection part, and an adhesive is injected into the adhesive injection part and cured. To provide an optical head, characterized by fixing the focusing coil to the coil holder by Rukoto.

According to this configuration, since the coil holder of the lens holder is solid, the weight of the lens holder alone increases, but the amount of adhesive used to fix the focusing coil is greatly reduced. Therefore, the weight can be reduced with the focusing coil attached.

Since the lens holder can be reduced in weight, a quick and smooth operation is possible during a tracking operation and a focusing operation. Further, the energy required for the operation is small, in other words, the power supplied to the tracking coil and the focusing coil may be small, and energy saving can be achieved. Furthermore, the force required for driving may be small,
Accordingly, smaller coils can be adopted as the tracking coil and the focusing coil, and the cost can be reduced accordingly.

Further, since the amount of the adhesive used for the focusing coil is small, the volume change during curing is small, and the stress generated during curing is small accordingly. Furthermore, since the lens holder is formed in a solid shape, the thickness from the outer surface to the inner surface of the shaft hole is large, and the lens holder has a high strength, so that the stress generated when the adhesive is cured Difficult to deform.

Since the shaft hole is not easily deformed by the stress generated when the adhesive is cured, the roundness of the shaft hole can be increased. Thus, the friction characteristics between the shaft and the shaft hole can be optimized, and the tracking operation and the focusing operation can be performed smoothly.

In order to achieve the above object, the present invention provides a bottom portion, a rising portion that protrudes perpendicularly to the bottom portion from an end portion of the bottom portion, and a columnar shape that protrudes in the same direction as the rising portion at a substantially center of the bottom portion. , A case having two permanent magnets that are arranged with the shaft sandwiched between the rising portions and that form a magnetic field between the shaft, a lens holding unit that holds an objective lens, and the lens holding unit A coil holding portion having a rectangular through-hole formed at substantially the center of the coil and a wall portion formed so as to surround the through-hole, and disposed in a space in the center of the rectangular through-hole and the coil holding portion. And a cylindrical shaft hole that can be fitted to the shaft so as to be able to rotate and make noise, and a rib that is connected to the four corners of the wall surface portion and is connected to the cylindrical shaft hole to fix the shaft hole. Department and front A magnetic plate that is bonded and fixed to the opposite side of the lens holding portion of the coil holding portion, a tracking coil that is bonded and fixed to the side surface of the lens holding portion, and a focusing coil that is externally fitted and fixed to the coil holding portion. A lens holder having
A wiring board that is attached to the case and the lens holder and supplies electric power to the tracking coil and the focusing coil, and the focusing coil is attached to the coil holding portion by fitting the focusing coil to the coil holding portion. An optical head is characterized in that it is installed and fixed to a coil holding part.

According to this structure, since the said coil holding part has penetrated the said lens holder in the rectangular shape, lens holder itself can be reduced in weight. Further, since the focusing coil is not bonded and fixed with an adhesive, it is possible to reduce the weight even when the focusing coil is attached.

Since the lens holder can be reduced in weight, a quick and smooth operation is possible during a tracking operation and a focusing operation. Further, the energy required for the operation is small, in other words, the power supplied to the tracking coil and the focusing coil may be small, and energy saving can be achieved. Furthermore, the force required for driving may be small, and accordingly, smaller coils can be adopted as the tracking coil and the focusing coil, and the cost can be reduced accordingly.

The lens holder may not have a rectangular through hole. In this case, the wall surface part connected in a rectangular shape from the lens holding part and the cylindrical shaft hole protrude from the lens holding part.

According to the present invention, it is possible to reduce the amount of adhesive when attaching the focusing coil to the lens holder, and to manufacture with high accuracy such as the roundness of the shaft hole through which the shaft passes,
Accordingly, it is possible to provide an optical head that can improve the accuracy of the focusing operation and the tracking operation and an optical disk device using the optical head.

In addition, according to the present invention, the amount of adhesive when attaching the focusing coil to the lens holder can be reduced, and the weight of the lens holder can be reduced while maintaining the strength, thereby reducing the energy required for manufacturing and operating the lens holder. It is possible to provide an optical head and an optical disc device using the optical head.

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a layout view of an optical disc apparatus according to the present invention. The optical disc apparatus shown in FIG.
It is a VD player. A DVD player PL shown in FIG. 1 is an optical disc (DVD recording medium).
A spindle motor Sp that rotates Ds, an optical head A that irradiates light to the optical disk Ds to read information, a decoder Dc that decodes a signal detected by the optical head A, and a monitor Mn that is an external display device An external connection part Oc for connection and a control part Cont are provided.

The DVD player PL is controlled by the control unit Cont. When a user gives a command to play a DVD, first, the spindle motor Sp is driven to rotate the optical disc Ds. The optical disk Ds rotating from the optical head A is irradiated with laser light, and the reflected light is detected by the optical head A. A light receiving element Pd, which will be described later, provided in the optical head A converts detected light into an electrical signal. The electrical signal is sent to the decoder Dc, demodulated into a video signal, and monitored via the external connection portion Oc. The image is sent to Mn and displayed on the monitor Mn.

FIG. 2 shows an arrangement plan of an example of the optical head. The optical head A shown in FIG. 2 has substantially the same structure as the conventional one. That is, the laser light source Ld, the mirror Mr, the collimator lens 3, the objective lens 4, the beam splitter Bs, and the light receiving element Pd are included. The laser light emitted from the laser light source Ld is reflected by the mirror Mr, enters the collimator lens 3, changes into parallel light, and exits from the collimator lens 3. The laser light emitted from the collimator lens 3 enters the objective lens 4 and is irradiated from the objective lens 4 to the optical disc Ds.

At this time, the laser beam is irradiated with the laser beam so that the recording layer of the optical disc Ds is focused and the optical axis is perpendicular to the recording layer of the optical disc Ds. The beam splitter Bs is a prism that transmits half of the incident laser light and reflects the half, and guides the light reflected by the optical disk Ds to the light receiving element Pd. The light receiving element Pd converts light into current,
Data is read by the intensity of light. The irradiation order of the laser light to each member described above is not limited to this, and the order may be changed within a possible range.

FIG. 3 is a plan view of the optical head according to the present invention, and FIG. 4 is a side view of the optical head shown in FIG.
As shown in FIGS. 3 and 4, the optical head A includes a base 1 that supports the collimator lens 3 and an actuator 2 that drives the objective lens 4. A side surface of the base 1 is formed adjacent to the sliding hole 11 and a sliding hole 11 through which a shaft 10 for slidably penetrating the optical head A in the disk track direction (disk radial direction) is formed. Rack gear 12 and a pinion gear 13 that meshes with the rack gear 12. Optical head A is pinion gear 13
Is transmitted to the rack gear 12 to slide. By sliding the optical head A, a laser spot is quickly irradiated onto a portion where necessary information on the recording surface of the optical disc Ds is recorded.

The actuator 2 is fixed to the base 1 with bolts. The actuator 2 is independent of a lens holder 21 for holding the objective lens 4, a case 22 in which the lens holder 21 is disposed, and a tracking coil 213 and a focusing coil 214 described later provided on the lens holder 21. And a wiring board 23 for supplying electric power.

The case 22 has a rectangular shape in plan view, and the bottom 221 and the periphery of the bottom 221 to the bottom 2
A rising portion 222 that rises perpendicularly to 21 and a rising portion 2 at a substantially central portion of the bottom portion 221.
22 has a cylindrical shaft 223 that protrudes in the same direction as 22, and two permanent magnets 224 that are arranged on the rising portion 222 and are opposed to each other with the shaft 223 interposed therebetween. The shaft 223 is made of a magnetic material, and a magnetic field is formed between the permanent magnet 224 and the shaft 223. The magnetic field of the permanent magnet 224 is not limited to this, but in any magnetic field, the direction of the lines of magnetic force is from the permanent magnet 224 toward the shaft 223. The bottom portion 221 is formed with a light passage hole 220 through which a laser beam passes.

5 is a side view of the lens holder used in the optical head shown in FIG. 3, FIG. 6 is a bottom view of the lens holder shown in FIG. 5, and FIG. 7 is not attached with the focusing coil of the lens holder shown in FIG. The side view of a state is shown. A lens holder 21 shown in FIG. 5 is formed in a lens holding part 211 for holding the objective lens 4 and a substantially rectangular coil in plan view, which is formed in the approximate center of the lens holding part 211 and into which a focusing coil 213 described later is fitted. The holding portion 215, the shaft hole 212 that is formed substantially at the center of the coil holding portion 215, and is fitted to the shaft 223 so as to be slidable and turnable, and the side surface of the lens holding portion 211 faces the shaft hole 212. Tracking coil 213 and focusing coil 2 arranged so as to surround shaft hole 212
14 and a magnetic plate 216 disposed on the lower surface of the focusing coil 214 so as to be orthogonal to the central axis of the shaft hole 212.

The shaft hole 212 is disposed so as to fit the shaft 223 outside. At this time, a magnetic field is generated between the permanent magnet 224 and the shaft 223 of the case 22, and a magnetic force is applied to the magnetic plate 216 by arranging the magnetic plate 216 in the magnetic field. With this magnetic force, the lens holder 2
1 is supported in a floating state without contacting the bottom 221.

Electric power is supplied from the wiring board 23 to the tracking coil 213 and the focusing coil 214. The wiring board 23 includes a main board 231 attached to the case 22, a sub board 232 attached to the lens holder 21, and a connection board 233 for connecting the main board 231 and the sub board 232. Wiring board 23 (at least connection board 233
) Is flexible so as not to be damaged by the tracking operation and focusing operation of the lens holder 21, for example, FFC (Flexible Flat Cable), FPC (Flexible Pr)
cable such as inted circuit).

The coil holding part 215 of the lens holder 21 is cut off at four corners to form an adhesive injection part 217. A focusing coil 214 formed by winding a conducting wire in advance in a rectangular shape is externally fitted to the coil holding portion 215 of the lens holder 21, and an adhesive is injected into the adhesive injection portion 217 so that the focusing coil 214 is attached to the coil holding portion 215. Adhere and fix. Here, since there is a sufficient thickness between the outer peripheral portion of the coil holding portion 215 and the shaft hole 212, deformation of the shaft hole 212 due to stress generated when the adhesive is cured can be suppressed. Compared to the conventional optical head, since the coil holder 215 is provided, the weight of the lens holder 21 itself is increased, but the amount of adhesive injected is greatly reduced, so that the focusing coil 21 is attached to the lens holder 21.
In the state where 4 is attached, the weight is reduced.

As shown in FIG. 5, the tracking coil 214 is a coil in which a conducting wire is wound in a rectangular shape.
A conducting wire extending in a direction parallel to the central axis of the shaft hole 212 is formed on the side surface of the lens holder 21.
3 and the permanent magnet 224 are formed so as to be within a magnetic field generated. The focusing coil 214 is a coil in which a conducting wire is wound in a rectangular shape, and is arranged so that the side surface of the conducting wire enters the magnetic field and surrounds the central axis of the shaft hole 212.

When a current flows through the conducting wire of the tracking coil 213, a Lorentz force is generated in a direction perpendicular to both the magnetic flux direction and the current flowing direction, that is, the circumferential direction of the shaft hole 212, in the conducting wire arranged in the magnetic field. The lens holder 21 can be rotated around the shaft 223 by adjusting the direction of current flow with the tracking coil 213 arranged with the shaft hole 212 interposed therebetween and adjusting the direction of the Lorentz force. That is, the objective lens 4 can be swung around the shaft 223 by appropriately changing the direction of current flow. By this swinging, it is possible to perform a tracking operation of moving the focal position of the objective lens 4 along the recording surface of the optical disc Ds and irradiating the laser spot at the correct position.

Similarly, when a current flows through a conducting wire disposed in the magnetic field of the focusing coil 214, a Lorentz force is generated in the direction perpendicular to both the magnetic flux direction and the current flowing direction in the conducting wire, that is, the axial direction of the shaft hole 212. To do. The lens holder 21 is moved to the shaft 2 by the Lorentz force.
23 slides in the axial direction. By appropriately changing the direction of the current, the lens holder 21 can be reciprocated in the axial direction of the shaft 223, and a focusing operation for focusing on the recording surface of the optical disc Ds can be performed.

FIG. 8 is a bottom view of another example of a lens holder used in the optical head shown in FIG. 3, and FIG. 9 is a side view of the lens holder shown in FIG. The lens holder 21b shown in FIG. 8 has the same structure as the lens holder 21 shown in FIG. 5 except that the coil holding portion 218 and the shaft hole 219 are different, and substantially the same parts are denoted by the same reference numerals. is there. The coil holder 218 of the lens holder 21b shown in FIGS. 8 and 9 has a rectangular through hole 2181 and a through hole 2181 at the approximate center of the lens holder 211.
Has a wall surface portion 2182 formed so as to surround. The inner peripheral surface of the through hole 2181 and the inner peripheral surface of the wall surface portion 2182 are formed so as not to have a step.

In addition, a shaft hole 219 that is slidably fitted on the shaft 223 of the case 22 so as to be pivotable is formed in the center of the space surrounded by the wall surface portion 2182. Ribs 2191 are arranged at four corners inside the wall surface 218, and the shaft hole 219 is firmly held by the ribs 2191. The rib portion 2191 is illustrated as being disposed at the four corners, but is not limited thereto, and the shaft hole 219 such as one having a plurality of rib portions in the axial direction can be firmly held. Things can be widely adopted. In addition, the shaft hole 2 is provided at the approximate center of the lens holding portion 211.
Only 19 may pass therethrough (without a rectangular through hole). in this case,
Since the rib portion 2191 that holds the shaft hole 219 can be reduced in size or omitted, the structure can be further simplified.

When the focusing coil 214 is attached to the lens holder 21b, the focusing coil 214 formed by winding a conducting wire in a rectangular shape in advance is used as the coil holding portion 2 of the lens holder 21.
15 is attached by external fitting. Since the coil holding part 218 has a rectangular shape,
It is possible to fix the focusing coil 214 to the coil holding part 218 without using an adhesive. The shaft hole 219 is deformed by the stress generated when the adhesive is cured,
It is possible to prevent the weight of the adhesive from increasing.

In the above embodiment, a DVD player is described as an example of an optical disk device, but the present invention is not limited to this, and information is read out by irradiating an optical disk with laser light, or information is recorded on a recordable optical disk. An optical disk device can be mentioned.

The optical head of the present invention can be applied to an optical disc apparatus that reads information by irradiating an optical disc such as a DVD, CD, or LD with laser light, or records information on a writable optical disc.

1 is a layout view of an optical disc device according to the present invention. FIG. FIG. 3 is a layout diagram of an example of an optical head. It is a top view of the optical head concerning the present invention. FIG. 4 is a side view of the optical head shown in FIG. 3. It is a side view of the lens holder used for the optical head shown in FIG. It is a bottom view of the lens holder shown in FIG. FIG. 6 is a side view of a state in which the focusing coil of the lens holder shown in FIG. 5 is not attached. It is a bottom view of the other example of the lens holder used for the optical head shown in FIG. It is a side view of the lens holder shown in FIG. It is a top view of an example of the actuator of the conventional optical head. It is a bottom view of the lens holder shown in FIG.

Explanation of symbols

Ds Optical disk Mr Mirror Bs Beam splitter Ld Laser light source Pd Light receiving part 1 Base 2 Actuator 21 Lens holder 211 Lens holding part 212 Shaft hole 213 Tracking coil 214 Focusing coil 215 Coil holding part 216 Magnetic plate 22 Case 221 Bottom part 222 Rising part 223 Shaft 224 Permanent magnet 23 Wiring board 231 Main board 232 Sub board 233 Connection board 3 Collimator lens 4 Objective lens

Claims (7)

A spindle motor that rotates an optical disc, an optical head that irradiates the optical disc with laser light, a signal processing device that processes signals, and a signal that is detected by the optical head and decoded by the signal processing device An external connection for connecting the signal to an external video display;
An optical disc device comprising a control unit,
The optical head includes a laser light source that irradiates laser light, a mirror that reflects the laser light, a collimator lens that makes the laser light parallel light, an objective lens for irradiating the optical disk with the laser light, A beam splitter that splits the light reflected by the optical disc, a light receiving element that receives the light and converts it into an electrical signal, an actuator that drives the objective lens, and a base to which the actuator is fixed,
The actuator includes a lens holder that holds the objective lens, a case in which the lens holder is disposed, and a wiring board that is attached to the case and the lens holder and supplies electric power.
The case includes a bottom portion, a rising portion that protrudes perpendicularly to the bottom portion from an end portion of the bottom portion, a columnar shaft that protrudes in the same direction as the rising portion at a substantially center of the bottom portion, and the rising portion. 2 which forms a magnetic field between the shafts arranged with the shaft in between
And permanent magnets,
The lens holder includes a lens holding portion that holds the objective lens, a coil holding portion that protrudes from substantially the center of the lens holding portion and is formed in a solid column shape with a substantially rectangular cross section, the lens holding portion, and the coil holding portion A cylindrical shaft hole that penetrates the portion and is fitted to the shaft so as to be rotatable and slidable; a magnetic plate that is bonded and fixed to the coil holding portion opposite to the lens holding portion; and the shaft hole And a tracking coil that is adhesively fixed to the side surface of the lens holding portion, and a focusing coil that is externally fitted and fixed to the coil holding portion,
Four corners of the coil holding part on which the focusing coil is externally fitted are cut to form an adhesive injection part, and an adhesive is injected into the adhesive injection part and hardened to cure the focusing coil. An optical disc apparatus fixed to the coil holding portion. A spindle motor that rotates an optical disc, an optical head that irradiates the optical disc with laser light, a signal processing device that processes signals, and a signal that is detected by the optical head and decoded by the signal processing device An external connection for connecting the signal to an external video display;
An optical disc device comprising a control unit,
The optical head has a laser light source for irradiating laser light, a mirror for reflecting the laser light,
A collimator lens that collimates the laser beam, an objective lens for irradiating the optical disc with the laser beam, a beam splitter that splits the light reflected by the optical disc,
A light receiving element that receives light and converts it into an electrical signal, an actuator that drives the objective lens, and a base to which the actuator is fixed;
The actuator includes a lens holder that holds the objective lens, a case in which the lens holder is disposed, and a wiring board that is attached to the case and the lens holder and supplies electric power.
The case includes a bottom portion, a rising portion that protrudes perpendicularly to the bottom portion from an end portion of the bottom portion, a columnar shaft that protrudes in the same direction as the rising portion at a substantially center of the bottom portion, and the rising portion. 2 which forms a magnetic field between the shafts arranged with the shaft in between
And permanent magnets,
The lens holder includes a lens holding portion that holds the objective lens, a rectangular through hole formed at a substantially center of the lens holding portion, and a coil holding portion that is formed so as to surround the through hole. A cylindrical shaft hole that is disposed in a central space of the rectangular through hole and the coil holding portion and can be fitted to the shaft so as to be rotatable and capable of noise, and at the four corners of the wall surface portion. A rib portion for connecting and fixing the shaft hole by connecting to the cylindrical shaft hole, a magnetic plate bonded and fixed to the side of the coil holding portion opposite to the lens holding portion, and a side surface of the lens holding portion And a tracking coil that is adhesively fixed to the coil holding portion and a focusing coil that is externally fitted and fixed to the coil holding portion.
An optical disc apparatus characterized in that the focusing coil is installed on and fixed to the coil holding part by fitting the focusing coil to the coil holding part. A bottom portion, a rising portion that protrudes perpendicularly to the bottom portion from an end portion of the bottom portion, a columnar shaft that protrudes in the same direction as the rising portion at a substantially center of the bottom portion, and the shaft at the rising portion. A case having a permanent magnet that is disposed between the shaft and forms a magnetic field between the shaft and
A lens holding part that holds the objective lens; a coil holding part that protrudes from a substantial center of the lens holding part and is solid in a columnar shape having a substantially rectangular cross section; a lens holding part that protrudes from a substantially central part of the coil holding part; A cylindrical shaft hole that penetrates the coil holding portion and is externally fitted to the shaft so as to be rotatable and slidable; and a magnetic plate that is adhesively fixed to the coil holding portion opposite to the lens holding portion; A lens holder having a focusing coil that is externally fitted and fixed to the coil holding portion;
A wiring board attached to the case and the lens holder and supplying power to the focusing coil;
At least one of the corners of the coil holding portion where the focusing coil is fitted is cut to form an adhesive injection portion, and the focusing is performed by injecting the adhesive into the adhesive injection portion and curing the adhesive. An optical head, wherein a coil is fixed to the coil holding part. A bottom portion, a rising portion that protrudes perpendicularly to the bottom portion from an end portion of the bottom portion, a columnar shaft that protrudes in the same direction as the rising portion at a substantially center of the bottom portion, and the shaft at the rising portion. A case having a permanent magnet that is disposed between the shaft and forms a magnetic field between the shaft and
A coil holding portion having a lens holding portion for holding an objective lens, a rectangular through hole formed at substantially the center of the lens holding portion, and a wall surface portion formed so as to surround the through hole; and the rectangular shape A cylindrical shaft hole that is disposed in the central space of the through hole and the coil holding portion and can be fitted to the shaft so as to be rotatable and capable of noise, and is connected to the four corners of the wall surface portion. A rib portion that fixes the shaft hole by connecting to the shaft hole, a magnetic plate that is bonded and fixed to the side of the coil holding portion opposite to the lens holding portion, and an outer fitting to the coil holding portion to be bonded and fixed. A lens holder having a focusing coil;
A wiring board attached to the case and the lens holder and supplying power to the focusing coil;
An optical head, wherein the focusing coil is installed and fixed to the coil holding part by fitting the focusing coil to the coil holding part. A lens holding part that holds the objective lens; a coil holding part that protrudes from a substantial center of the lens holding part and is solid in a columnar shape having a substantially rectangular cross section; a lens holding part that protrudes from a substantially central part of the coil holding part; A lens holder that has a cylindrical shaft hole that penetrates the coil holding portion and is externally fitted to the shaft so as to be rotatable and slidable, and a focusing coil that is externally fitted and fixed to the coil holding portion. Have
At least one of the corners of the coil holding portion where the focusing coil is fitted is cut to form an adhesive injection portion, and the focusing is performed by injecting the adhesive into the adhesive injection portion and curing the adhesive. An optical head, wherein a coil is fixed to the coil holding part. A lens holding portion for holding the objective lens, a coil holding portion having a rectangular wall surface portion, and a space that is disposed in the center of the rectangular wall surface portion and is fitted on the shaft so as to be rotatable and capable of noise. A cylindrical shaft hole that can be fixed, a rib portion that supports the shaft hole by connecting to the wall surface portion and the cylindrical shaft hole, and a focusing coil that is externally fitted and fixed to the coil holding portion And a lens holder having
An optical head, wherein the focusing coil is installed and fixed to the coil holding part by fitting the focusing coil to the coil holding part. The optical head according to claim 6, wherein the rectangular portion surrounded by the wall surface portion penetrates the lens holding portion.

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