JPH0817150A - Optical information recording/reproducing apparatus - Google Patents

Abstract

PURPOSE:To simplify the prepressurizing mechanism of an optical head and reduce the size and thickness of an apparatus by a method wherein the prepressurizing mechanism is composed of a magnet and the optical head is pressed against a guide shaft and the optical head is restricted on the guide shaft in a direction other than an access direction. CONSTITUTION:A magnet 71 is attached to the lower side of an optical head 4 in a longitudinal direction (x-axis direction) with an inclination angle theta -30 degrees. An attracting member 74 made of steel is placed on a subbase 2 in a longitudinal direction so as not to touch the magnet 71. With this construction, an attracting force F1 in a (-z) direction is applied to a first guide shaft 18 and an attracting force F2 having components in a (y) direction and in a (-z) direction is applied to a second guide shaft 19. The second guide shaft 19 is used as a reference and four fixed rollers 22 are mated with the guide shaft 19 so along the guide shaft 19, so that the rotation of the optical head 4 around the x-axis can be restricted.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical information recording / reproducing apparatus, and more particularly to an optical information recording / reproducing apparatus which is small and thin, has a good assembling property, and is excellent in high-speed and high-precision positioning of an optical head.

[0002]

2. Description of the Related Art Conventionally, optical disk file devices and CD-
In an optical information recording / reproducing apparatus such as a ROM, various drive mechanisms and guide mechanisms for positioning the optical head in the radial direction of the disk at high speed and with high precision have been devised. In order to position the optical head at high speed and with high accuracy, a highly rigid optical head structure and a guide mechanism structure are required so that pitching and yawing of the optical head are unlikely to occur in a high frequency region.

Devices related to this type of device are disclosed, for example, in JP-A-63-13132 and JP-A-61-15.
There is a publication such as 0169. In these apparatuses, linear motors for driving the optical head are arranged on the left and right sides of the optical head, respectively, and a guide mechanism for supporting the optical head is formed outside or inside the linear motor. Further, in order to make the device dimensions the same as those of a widely used floppy disk device, it is necessary to make the drive mechanism and the guide mechanism smaller and thinner. A device related to this kind of device is disclosed in, for example, JP-A-61-269267.
Japanese Patent Publication No. 60-182522 and the like. In these devices, a guide mechanism is constituted by a preload mechanism using a leaf spring.

An example in which the attraction force of a magnet is applied to a transfer device of an optical head in order to prevent backlash due to external vibration and to perform smooth movement is disclosed in Japanese Utility Model Laid-Open No. 62-67362. There are examples described in Japanese Patent No. 68731 and Japanese Utility Model Laid-Open No. 62-90466.

[0005]

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention
In the technique disclosed in Japanese Patent No. 9267, etc., a preload guide mechanism using a leaf spring or the like is designed to restrain the optical head on the guide shaft in a direction other than the access direction. However, there are problems that the number of parts of the apparatus is large and the thickness of the apparatus cannot be reduced.

Further, in the technique described in Japanese Utility Model Laid-Open No. 62-67362, the direction of the attraction force is vertical to the disk surface, so that the degree of freedom other than the access direction of the optical head can be restricted. Since it is difficult, there is a possibility that a smooth straight movement cannot be obtained. Further, since one of the two guide shafts penetrates the optical head, there is a problem that the optical head cannot be easily removed from the guide shaft in the vertical direction of the disk surface.

An object of the present invention is to simplify the preload guide mechanism of the optical head, to reduce the size and thickness of the apparatus, to smoothly move the optical head, and to provide an optical information recording / reproducing apparatus having a simple and excellent assembling performance. To provide.

[0008]

To achieve the above object, the present invention is directed to moving an optical head in a radial direction of a disk,
Of the guide mechanism for positioning, the preload mechanism is composed of a magnet, the optical head is pressed against the guide shaft with a predetermined pressure, and the optical head is constrained on the guide shaft in a direction other than the access direction. is there.

Specifically, a disc for recording information, a rotation driving device for the disc, an optical head for supporting an objective lens and optical means for recording or reading information on the disc, and a base for supporting the optical head. ,
A permanent magnet for guide preload and a magnetic body for guide preload provided on the optical head and the base so as to face each other,
A coarse actuator and a guide mechanism unit for moving and positioning the optical head in the radial direction of the disc are provided, and the guide preload permanent magnet and the guide preload magnetic body attract each other, In an optical information recording / reproducing apparatus in which the optical head is attracted toward the base and a preload is applied to a guide system, the optical head includes a plurality of fixed rollers, and a first and a second roller provided on the base. The permanent magnet and the magnetic body for preloading the guide are installed between the second guide shafts, and the permanent magnet and the magnetic body are installed on a plane inclined by about 30 to 60 degrees with respect to a plane passing through the axial centerlines of the first and second guide shafts. All of the fixed rollers are pressed against the first and second guide shafts by the generated preload, so that the degree of freedom other than the positioning direction of the optical head is increased. As well as a structure that is flux, is characterized in that a structure detachable said optical head in assembled state relative to the guide system.

Further, the first and second guide shafts are provided on the base, and the four fixed rollers engaging with the second guide shaft have the center lines of the two fixed rollers as the first and second guide shafts. Substantially parallel to a plane passing through the axis center lines of the second guide shafts, the axis center lines of the remaining two fixed rollers are substantially perpendicular to the plane passing through the axis center lines of the first and second guide shafts. The one fixed roller engaged with the first guide shaft has a shaft center line substantially parallel to a plane passing through the shaft center lines of the first and second guide shafts. Installed on the optical head, the permanent magnet for guide preload and the magnetic body are installed between the first and second guide shafts, and with respect to a plane passing through the axial center lines of the first and second guide shafts,
Due to the preload generated on the plane inclined by about 30 to 60 degrees, all of the fixed rollers are moved to the first and second sides.
When the optical head is pressed against the guide shaft, the degree of freedom of the optical head other than the positioning direction is restricted, and the assembled optical head is attachable to and detachable from the guide system. It is what

[0011]

According to the above construction, there are the following actions. The guide shaft is arranged outside the optical head, the guide shaft does not penetrate the optical head, and the optical head can be easily attached to and detached from the guide system in a state where the guide preload is applied by the magnetic attraction force. By generating a magnetic attraction force for guide preload in an oblique direction with respect to a plane passing through the centers of the first and second guide shafts, the degree of freedom other than the head positioning direction is restricted, and highly accurate linear movement is possible. become. Since the preload mechanism of the optical head is configured by using a magnet, it is possible to reduce the number of parts that configure the preload mechanism, to reduce the size and thickness of the device, and to take the structure in which the optical head is attracted to the guide shaft by the magnet. All that is required is to mount the optical head on the guide shaft, which facilitates assembly.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Some embodiments of the present invention will be described below with reference to the drawings. Before entering into a detailed description of an optical head driving device, which is a characteristic part of the optical information recording / reproducing apparatus according to the present invention, the positioning of the optical head driving apparatus in the entire optical information recording / reproducing apparatus is described. Explain what is going on.

FIG. 1 is a perspective view including a partial cross section of an optical information recording / reproducing apparatus according to an embodiment of the present invention. In FIG. 1, an information recording optical disc 1 is rotationally driven by a disc drive motor 3 mounted on a sub base 2. The disk drive motor 3 is driven by the disk motor driver 16.

The optical head 4 has a built-in optical means (not shown) for recording and reproduction, an objective lens 7, and an objective lens actuator 8. The objective lens actuator 8 can focus the objective lens on the recording surface of the information recording optical disc and can precisely drive the objective lens in the radial direction of the information recording optical disc. A semiconductor laser (not shown) built in the optical head 4 is driven by a semiconductor laser driver 17 so as to always obtain a stable optical output.

The optical head 4 is supported by an optical head guide mechanism arranged on the sub-base 2 and is driven in the radial direction of the information recording optical disk 1 by a tracking linear servomotor 5 so as to move it to the entire track. Access operation is performed. In FIG. 1, one tracking linear servomotor 5 is arranged on one side of the optical head 4, but one tracking linear servomotor 5 may be arranged on each side of the optical bed 4. The tracking linear servomotor 5 is driven by a servo control circuit 10 and a tracking servomotor driver 11 based on a command from the system control microprocessor 9.

The speed of the optical head 4 is controlled by the output of the linear encoder 6. In the focusing operation and the precision tracking operation of the objective lens, the output of the photodetector (not shown) built in the optical head 4 is amplified and calculated by the preamplifier 12 and the signal processing circuit 13 to generate a control signal, This is done by driving the objective lens actuator 8.

FIG. 2 is a plan view including a partial cross section of an optical head driving device in an optical information recording / reproducing device according to an embodiment of the present invention, and FIG. 3 is a part of FIG. 2 seen from the x-axis direction. FIG. 4 is a front view including a cross section, and FIG. 4 is a left side view of FIG. 2 viewed from the −y axis direction, in which the magnetic circuit of the linear tracking servomotor and the sub-base are removed.

In FIG. 2, the optical head 4 is an information recording optical disk (not shown) by means of two linear tracking servomotors 5 arranged on a sub-base (not shown).
Can be moved in the radial direction (x-axis direction), and a rough access operation for moving to an arbitrary track is performed. The optical head 4 supports a first guide shaft 18 arranged on a sub-base (not shown) and six rollers mounted on the optical head 4 on a second guide shaft 19 to support the optical head. To guide. The first guide shaft 18 and the second guide shaft 19 are fixed with screws 21 on a sub base (not shown) using a guide shaft retainer 20.

Five of the six rollers described above are fixed rollers 22 and 25, and the fixed rollers are attached to the optical head 4. A detailed view of the fixed roller is shown in FIG. Although the fixed roller shown in FIG. 5 is engaged with the integral member 23 of the inner ring and the shaft, a straight shaft may be press-fitted into a general rolling bearing. The fixed roller has a shaft 2
The side 3 is attached to the optical head 4 by press fitting or bonding. As shown in FIGS. 2 and 3, the preload roller 24 is disposed on the optical head 4 side at a position where one fixed roller 25 and the first guide shaft 18 are sandwiched, and a predetermined pressure is applied by the spring reaction force to the first guide. It is pressed against the shaft. This allows
The optical head can be constrained on the guide shaft.

A detailed view of the preload mechanism of the preload roller is shown in FIGS. 6 and 7. FIG. 6 is a plan view of the preload mechanism section, and FIG.
Is a front view. The preload mechanism section includes a preload roller 24, a preload roller shaft 25, and a preload spring 26. Preload roller 24
A preload roller shaft 25 is press-fitted in the preload roller shaft, and a part of the preload spring 26 is wound around the preload roller shaft.
(Not shown), and attach to the optical head. When the preload roller 24 is engaged with the first guide shaft (not shown), the preload spring 26 is slightly bent. Therefore, the preload roller applies a preload to the first guide shaft by the spring reaction force.

The manner in which the guide shaft, the fixed roller, and the preload roller are rollingly engaged will be described with reference to FIG. FIG. 8 is an enlarged view of the engaging portions of the guide shaft, the fixed roller, and the preload roller of the optical information recording / reproducing apparatus of the present invention shown in FIG. In the fixed roller 25 rollingly engaged with the first guide shaft 18, the line connecting the contact point 29 between the first guide shaft 18 and the fixed roller 25 and the center 30 of the first guide shaft 18 is substantially parallel to the z axis. The optical head 4 is thus arranged.

The preload roller 24 is composed of the first guide shaft 1
8 is arranged in the optical head 4 so that the line connecting the contact point 31 of the preload roller 24 and the center 30 of the first guide shaft 18 forms an angle of approximately 180 ° + β with respect to the y-axis. Second guide shaft 1
There are four fixed rollers 22 that roll-engage with 9. xy
The two fixed rollers 22 above the plane are arranged such that the line connecting the contact point 32 between the second guide shaft 19 and the fixed roller 22 and the center 33 of the second guide shaft 19 is substantially parallel to the z axis. Then, the optical head 4 is arranged.

Further, regarding the two fixed rollers 22 located below the xy plane, the line connecting the contact point 34 between the second guide shaft 19 and the fixed roller 22 and the center 33 of the second guide shaft 19 is y.
The optical head 4 is arranged so as to form an angle of −β with respect to the axis. In order to constrain the optical head 4 in both the y and z directions, the angle β is set to about 45 °.

Next, a tracking linear servomotor for driving the optical head in the radial direction of the information recording optical disk will be described. As shown in FIG. 3, the linear tracking servomotor comprises a drive coil 36 wound around a bobbin 35, a center yoke 37, an outer yoke 38, and a magnet 39. The bobbin 35 is fixed to the optical head 4 with a screw 40 as shown in FIG.

FIG. 9 is a detailed view of the linear tracking servomotor, and is a view seen from the y-axis direction in FIG. The bobbin 35 fixed to the optical head 4 (not shown) is arranged in non-contact with the center yoke 37. The magnet 39 has its s-pole surfaces adhered and fixed to the upper and lower outer yokes 38 of the center yoke 37, and the center yoke 37 and the upper and lower outer yokes 38 are fixed to the sub-base 2 with screws 41. When the above magnetic circuit is configured, the magnetic field B is generated in the direction of the arrow. When a current I is passed through the drive coil 36, a force F ₁ is generated in the direction of the arrow and the optical head can be driven.

Next, the deviation between the center of gravity of the optical head and the thrust center will be described with reference to FIG. The linear tracking servomotor has two upper and lower surfaces of the drive coil 36,
Thrust is generated from a total of four surfaces, that is, surfaces 43 and 44. The thrusts generated by the two sets of magnetic circuits arranged above and below the center yoke 37 are F ₁ because the dimensions of the magnetic circuits are the same, and when the thrusts from the above-mentioned four thrust generating surfaces are combined, the thrust force in the z-axis direction is calculated. The thrust center will be on the line 45.

On the other hand, in the present embodiment, since the optical head guide mechanism is arranged below the center of gravity 46 of the optical head 4, the center of gravity is lower than that of the conventional device, and the thrust center line 45.
The center of gravity 46 can be adjusted to a position substantially close to. For this reason, it is possible to avoid that a moment is generated at the time of driving due to a difference between the center of gravity of the optical head and the center of thrust as in the conventional device, and that the pitching operation is not easily excited, and a wide speed control system band can be secured. High-speed and high-accuracy access.

When the guide mechanism system is constructed as in this embodiment, the first guide shaft 18 and the second guide shaft 19 can be brought into contact with and fixed to the sub-base 2 over a wide range. Therefore, compared to the case where the guide shaft is supported at both ends as in the conventional case, the bending rigidity of the guide shaft is less problematic, and even if a device having a large stroke of the optical head is configured, the diameter of the guide shaft is large. It has the advantage of not having to.

FIG. 10 shows another embodiment of the optical information recording / reproducing apparatus of the present invention, and is a front view including a partial cross section as viewed from the x-axis direction. Those having the same reference numerals as those in FIG. 3 are the same parts. In this embodiment, the numbers of the fixed rollers 22 and 25 and the preload rollers 24 which are rolling-engaged with the first guide shaft 18 and the second guide shaft 19 are the same as those in the embodiment shown in FIG. 3, but in the xy plane. The mounting angle of the fixed roller above is different from that of the previous embodiment.

The engagement of the guide shaft, the fixed roller and the preload roller will be described with reference to FIG. Second guide shaft 1
9 out of the four fixed rollers 22 that roll-engage with 9
The two fixed rollers 22 located above the y-plane have a line connecting the contact point 32 between the second guide shaft 19 and the fixed roller 22 and the center 33 of the second guide shaft 19 with an angle β with respect to the y-axis. The optical head 4 is arranged so as to be formed.

Further, the line connecting the contact point 29 of the fixed roller 25 rollingly engaged with the first guide shaft 18 with the first guide shaft 18 and the center 30 of the first guide shaft 18 is approximately 1 with respect to the y-axis.
The optical head 4 is arranged so as to form an angle of 80 ° -β. In order to constrain the optical head 4 in both the y and z directions, the angle β is set to about 45 °.

FIG. 12 shows another embodiment of the optical information recording / reproducing apparatus of the present invention, and is a plan view including a partial cross section as seen from the x-axis direction. Those having the same reference numerals as those in FIG. 3 are the same parts. In this embodiment, the first guide shaft 18 and the preload roller 49
, The second guide shaft 19 and the fixed roller 48
Engage with each other. The fixed roller includes a drum-shaped roller, two back-to-back miniature rolling bearings, and one shaft.
The shaft is fixed to the optical head 4. Further, the preload roller constitutes a preload mechanism using a preload leaf spring as in the embodiment shown in FIG.

Now, regarding the optical head driving device in the optical information recording / reproducing apparatus of one embodiment of the present invention,
I will reiterate. 13 is a plan view including a partial cross section of the optical head driving device, FIG. 14 is a front view including a partial cross section of FIG. 13 seen from the x-axis direction, and FIG. 13 is seen from the −y axis direction. FIG. 4 is a left side view, and a diagram excluding the magnetic circuit of the linear tracking servo motor and the sub-base is as shown in FIG. 4.

In FIG. 13, the optical head 4 is moved in the radial direction (x-axis direction) of an information recording optical disk (not shown) by two linear tracking servomotors 5 arranged on a sub base (not shown). It is movable and performs a rough access operation for the purpose of moving to an arbitrary track.

The optical head 4 has a sub base (not shown).
The first guide shaft 18 made of steel and the second guide shaft 19 made of steel arranged above are engaged with five fixed rollers 22 attached to the optical head 4 to support and guide the optical head.
The first guide shaft 18 and the second guide shaft 19 are fixed with screws 21 on a sub base (not shown) using a guide shaft retainer 20.

The fixed roller 22 is as described with reference to FIG. 5, but the manner in which the fixed roller roll-engages with the guide shaft will be described with reference to FIG.
FIG. 15 is an enlarged view of the guide shaft and the engaging portion of the fixed roller of the optical information recording / reproducing apparatus of the present invention shown in FIG. In the fixed roller 25 rollingly engaged with the first guide shaft 18, the line connecting the contact point 29 between the first guide shaft 18 and the fixed roller 25 and the center 30 of the first guide shaft 18 is substantially parallel to the z axis. The optical head 4 is thus arranged. Second guide shaft 19
There are four fixed rollers in rolling engagement with.

In the two fixed rollers 22 located above the xy plane, the line connecting the contact point 32 between the second guide shaft 19 and the fixed roller 22 and the center 33 of the second guide shaft 19 with respect to the z-axis. Are arranged on the optical head 4 so as to be substantially parallel to each other. In addition, the two fixed rollers 22 below the xy plane
Is arranged in the optical head 4 such that the line connecting the contact point 34 between the second guide shaft 19 and the fixed roller 22 and the center 33 of the second guide shaft 19 is substantially parallel to the y-axis.

The basic idea is that the second guide shaft 1
Based on 9 as a reference, four fixed rollers 22 are made to follow and roll-engage with each other, and the optical head 4 is caused to perform a rectilinear motion. With this alone, the optical head 4 cannot be constrained within the xy plane. Therefore, the first guide shaft and one fixed roller 25 rollingly engaged with the first guide shaft are provided to restrain the rotation of the optical head 4 about the x-axis. In order to restrict the movement of the optical head 4 other than the rectilinear movement direction (x-axis direction), it is necessary to apply a preload to the roller to support and guide the optical head on the guide shaft.

Now, in order to restrain the optical head in both the y-axis direction and the z-axis direction, a preload mechanism for pressing the optical head against the guide shaft with a predetermined pressure has been conventionally used. However, the preload mechanism is a complicated mechanism by a combination with a preload leaf spring.

Therefore, in this embodiment, in order to simplify the preload mechanism and to reduce the size and thickness of the entire apparatus, as shown in FIG. 13, magnets 71 are arranged at four locations in the optical head 4 and made of steel. To the 1st guide shaft 18 and the 2nd guide shaft 19, four fixed rollers 22 are used for the guide shaft 19 and one fixed roller 25 is used for the guide shaft 18 using the attractive force of a magnet.
The optical head 4 is constrained by being pressed against. The guide shaft and the magnet are arranged in a non-contact manner.

The magnet 71 for generating the attractive force is shown in FIG.
As shown in FIG. 4, the optical head 4 is installed on the second guide shaft 19 so as to generate a suction force F ₂ indicated by an arrow having a component in the −y direction and a component in the −z direction. In the case of the present embodiment, the angle of the mounting surface of the magnet 71 is set to approximately -45 degrees. Further, with respect to the first guide shaft 18, the optical head 4 is installed so as to generate a suction force F ₁ indicated by an arrow having a component in the −z direction. By the above method, the optical head can be constrained in both the y direction and the z direction.

How to attach the magnet to the optical head 4 will be described with reference to FIG. FIG. 16 is a view of the housing portion of the optical head as viewed from the back side. The same symbols as in FIG. 14 are the same parts. Among the magnets, the magnets arranged on the side of the first guide shaft (not shown) have 1
Install one by one. Further, one magnet is arranged on the second guide shaft (not shown) side, and one magnet is attached to the surface 73. The surface 73 forms an angle of about 45 degrees with the surface 74, and by mounting the magnet on the surface 73, the optical head 4 can be constrained on the second guide axis in the y and z axis directions.

The tracking linear servomotor for driving the optical head in the radial direction of the information recording optical disk has been described in detail with reference to FIGS.

Now, with the above configuration,
It will be described with reference to the examples described in FIGS. 2 and 3 that the number of parts forming the preload mechanism can be reduced and the device can be made smaller and thinner. With the configuration shown in FIGS. 2 and 3, four types of components, that is, a total of five components, are required to form the preload mechanism unit, but in the present embodiment, it is only necessary to prepare four magnets of the same type. Further, since a preload is applied in one direction by the preload leaf spring 26, the mounting angles of the fixed roller 22 engaging with the second guide shaft 19 and the preload roller 24 engaging with the first guide shaft 18 are shown in FIG. Unlike the embodiment shown, the height dimension of the device tends to be large.

When the height from the lowermost part of the guide system of the optical head to the upper end part of the objective lens actuator is h,
In the embodiment shown in FIG. 14, the dimension h can be reduced by about 20% compared to the example using the preload leaf spring shown in FIG. When a preload leaf spring is used, the assembly is complicated because the guide shaft is sandwiched between the fixed roller and the preload roller. However, in the present embodiment, the optical head is attracted to the guide shaft by a magnet. Therefore, it is only necessary to mount the optical head on the guide shaft, and there is a feature that assembly is easy.

In the embodiment described above, four magnets are attached to the optical head, but the number of magnets attached is not limited to this. That is, as described above, it suffices to apply a preload to the optical head so as to restrain translational and rotational movements other than the movement direction thereof. As a method for realizing this, as shown in FIGS. A method using a single magnet may be used.

FIG. 17 is a plan view of another embodiment of the optical information recording / reproducing apparatus of the present invention, and those having the same reference numerals as those in FIG. 14 are the same parts. 18 is a front view. FIG.
, The magnet 71 is attached to the lower side of the optical head 4 in the longitudinal direction (x-axis direction) at an angle of approximately θ = −30 degrees, and the steel-made adsorbent 74 on the sub-base 2 is different from the magnet 71. They are also arranged in the longitudinal direction without contact. Then, the optical head 4 is attracted toward the adsorbent 74 by the attraction force F _t . By doing so, the attraction force F _{1 in the} −z direction with respect to the first guide shaft 18
And causing the suction force F ₂ with -y direction and -z direction component with respect to the second guide shaft 19.

By the suction force F ₂ , the second guide shaft 19 is used as a reference and four fixed rollers 22 are imitated in rolling contact with the second guide shaft 19 so as to follow the linear movement of the optical head 4.
The fixed roller 25 can be pressed against the first guide shaft 18 by the suction force F ₁ to be rollingly engaged therewith to restrain the rotation of the optical head 4 about the x-axis. The positional relationship between the magnet and the adsorbent is not limited to this. Contrary to this embodiment, the adsorbent may be attached to the optical head, and the magnet may be arranged on the sub-base in a non-contact manner with the adsorbent to apply a guide preload.

FIG. 19 shows an embodiment in which the system of the present invention is applied as it is to the apparatus having the preload mechanism using the conventional leaf spring shown in FIG. Those having the same reference numerals as those in FIG. 3 are the same parts. The magnet 71 is provided in the optical head 4 as in the embodiment shown in FIG. 18, and is attracted by the steel adsorbent 74 arranged on the sub-base 2 to generate the guide preload F _t .

20 and 21 show another embodiment of the optical information recording / reproducing apparatus of the present invention. FIG. 20 is a plan view and FIG. 21 is a front view. In this embodiment, FIG. 13 and FIG.
Similar to the embodiment shown in FIG. 4, one fixed roller 25 is engaged with the first guide shaft 18. In addition, the second guide shaft 19
And two hourglass-shaped fixed rollers 48 are engaged. The drum-shaped fixed roller is composed of a drum-shaped roller, two back-to-back miniature rolling bearings, and one shaft, and the shaft is the optical head 4.
It is fixed to.

FIG. 22 shows another embodiment of the optical information recording / reproducing apparatus of the present invention. In this embodiment, FIG. 13 and FIG.
Although the same number of fixed rollers as in the embodiment shown in FIG. 4 are arranged on the first guide shaft and the second guide shaft, the fixed roller installation angle is different from that of the previous embodiment.

FIG. 23 is an enlarged view of the engaging portions of the guide shaft and the fixed roller in the embodiment shown in FIG. Second
Of the four fixed rollers 22 rollingly engaged with the guide shaft 19, the two fixed rollers 22 located above the xy plane.
Is a line connecting the contact point 32 between the second guide shaft 19 and the fixed roller 22 and the center 33 of the second guide shaft 19 with respect to the y axis.
Are arranged on the optical head 4 so as to make an angle of. In addition, the first of the fixed roller 25 which is in rolling engagement with the first guide shaft 18
The optical head 4 is arranged so that the line connecting the contact point 29 with the guide shaft 18 and the center 30 of the first guide shaft 18 forms an angle of approximately 180 ° -β with respect to the y-axis. In order to constrain the optical head 4 in both the y direction and the z direction, the angle β is set to about 45 degrees.

As described above, in another embodiment of the optical information recording / reproducing apparatus of the present invention shown in FIGS. 19, 20, 21 and 22, the magnet 71 is provided in the optical head 4 and the magnet is provided on the sub base 2. It is sucked by the steel-made adsorbent 74 arranged in the above position to generate the guide preload F _t . However, contrary to the present embodiment, the adsorbent may be attached to the optical head, and the magnet may be arranged on the sub-base to apply the guide preload. Further, as in the embodiment shown in FIGS. 13 and 14, a structure in which a plurality of magnets are arranged in the vicinity of the fixed roller to exert a guide preload may be adopted.

24 and 25 also show another embodiment of the optical information recording / reproducing apparatus of the present invention. 24 is a front view and FIG. 25 is a back view. The same parts as those in FIGS. 13 and 14 are the same parts. The optical head 4 has a drive coil 36 composed of a plurality of divided coils (in this embodiment, divided into five).
Is provided. Similar to the embodiment shown in FIGS. 13 and 14, five fixed rollers 22 fixed to the optical head.
Is rollingly engaged with guide shafts 51 and 52 having rectangular cross sections as shown in FIG.

13 and 14 is different from the embodiment shown in FIGS. 13 and 14 in that the guide shafts 51 and 52 also serve as the outer yoke of the tracking linear servo motor in order to make the device thinner and thinner. In order to access the optical head at high speed, a tracking linear servomotor having a large thrust is required. For that purpose, in order to obtain a large gap magnetic flux density, it is necessary to increase the thickness of the yoke and the magnet that form the tracking linear servomotor, and the magnetic circuit dimension h ₁ shown in FIG. 14 tends to increase.

In the embodiment shown in FIGS. 13 and 14,
A magnetic circuit is formed by sandwiching the drive coil 36 in the upper and lower directions, and has thrust generation surfaces on the upper and lower two surfaces of the drive coil. In order to prevent the saturation of the magnetic flux, it is necessary to select the total thickness of the two outer yokes 39 arranged above and below the drive coil to be substantially equal to the thickness of the center yoke 37. That is, the thickness of the center yoke 37 is required to be almost double that of the outer yoke 39.

In the embodiment shown in FIGS. 24 and 25, in order to reduce the thickness of the magnetic circuit, as shown in FIG. 24, the center yoke 39 is reduced to about half the thickness of the conventional one.
The drive coil 36 is disposed in the optical head so as to surround the magnet 37 and the magnet 37 without contacting them.

Further, an outer yoke 38 is arranged on the upper surface of the drive coil, and outer yokes 51 and 52 made of a magnetic material which also serve as guide shafts and a magnet 39 are arranged on the lower surface, and both ends of the outer yokes 38, 51 and 52 and the center yoke 37 are arranged. To form a magnetic circuit. FIG. 26 is a side view including a partial cross section of the magnetic circuit. As shown in FIG. 26, the magnets are bonded on the center yoke 37 and the outer yoke 51 while alternately changing their polarities. The drive coil is formed by bonding a plurality of split coils (five split coils are used in the present embodiment).

Now, let us consider the generation of thrust by focusing on the central coil 60 of the five-divided coil 36. A magnetic field B acts on the coil 60 in the direction of the arrow. When the current I is passed, a thrust F is generated in the direction of the arrow, and the optical head is driven to the left. The coils 59 and 61 adjacent to the coil 60 also generate a thrust in the left direction by passing the current I in the same direction. Since the directions of the magnetic fields acting on the coils 58 and 62 at both ends are opposite to those of the other coils, the current I can be applied in the opposite direction to generate thrust in the left direction.

Each time the coils move and the direction of the magnetic field action from the opposing magnets changes, the direction of the current I is switched appropriately, and the directions of the thrust generated by the coils are aligned in the desired direction. The head can be driven.
The reason why the width of the center yoke can be reduced to about half that of the conventional device is that a plurality of magnets having different polarities are arranged, so that the number of magnetic fluxes passing through the center yoke is significantly reduced, and even a thin yoke can reduce the magnetic flux. This is because saturation can be suppressed.

Next, the preload guide mechanism will be described. The preload guide mechanism of this embodiment is almost the same as that of the embodiment shown in FIGS. 13 and 14. As shown in FIG. 25, two pieces are generated to generate a preload, and a suction force is generated toward the right guide shaft 51, and a suction force is generated toward the left guide shaft 52. Therefore, four magnets 71 are provided in the optical head 4. Each magnet is bonded to a block 53 protruding from the optical head 4. However, the number and installation positions of the magnets to be used are not limited to this. Each magnet generates an attractive force toward the guide shafts 51 and 52 in the directions indicated by arrows and circles. The engaging surfaces of the guide shafts 51 and 52 with which the fixed roller 22 rolls and engages are flat, and the contact between them is a line contact.

In the embodiment shown in FIGS. 13 and 14, the point contact is made, and in this embodiment, the fixing force of the fixed roller is larger and a larger rigidity can be obtained. Next, the deviation between the center of gravity of the optical head and the thrust center will be considered with reference to FIG. The linear tracking servomotor generates thrust forces F from the upper and lower two surfaces of the drive coil 36, which is a total of four surfaces. When these are combined, the thrust center in the vertical direction is the line 6
4 will be present.

In this embodiment, since the optical head guide mechanism is arranged below the center of gravity 63 of the optical head 4,
The center of gravity of the movable part is lower than that of the conventional device, and the center of gravity 63 of the movable portion can be adjusted to a position substantially close to the thrust center line 64. Since the objective lens actuator 8 is mounted above the optical head 4, the center of gravity of the movable part tends to be located above.

In the embodiment shown in FIGS. 13 and 14, the magnet 39 and the outer yoke 38 are symmetrically arranged above and below the driving force coil 36, whereas in the present embodiment, the outer yoke 38 is provided above the driving coil 36. Have only placed.
Therefore, the drive coil can be arranged in the optical head 4 further upward toward the disc cartridge 47. Therefore, the thrust center can be adjusted in the direction of the center of gravity.
For this reason, it is possible to avoid that a moment is generated at the time of driving due to a difference between the center of gravity of the optical head and the center of thrust as in the conventional device, and that the pitching operation is not easily excited, and a wide speed control system band can be secured. High-speed and high-accuracy access.

Further, when the guide mechanism system is constructed as in this embodiment, the guide shaft 51 can be contacted and fixed on the sub base 2 over a wide range. Therefore, compared to the conventional case where the guide shaft is supported at both ends,
The bending rigidity of the guide shaft is less of a problem, and there is an advantage that the cross-sectional area of the guide shaft does not need to be large even if a device having a large stroke of the optical bed is configured.

[0066]

As described above, according to the present invention, of the guide mechanism for moving and positioning the optical head in the radial direction of the disk, the preload mechanism is constituted by using a magnet, so that the optical head is set on the guide axis. By pressing with pressure, the optical head can be restrained on the guide shaft in a direction other than the access direction. As a result, the number of parts constituting the preload mechanism can be reduced, and the size and thickness of the device can be reduced. Furthermore, since the optical head is attracted to the guide shaft by the magnet, it is only necessary to mount the optical head on the guide shaft, and there is an effect that the assembly is easy.

[Brief description of drawings]

FIG. 1 is a perspective view including a partial cross section of an optical information recording / reproducing apparatus according to an embodiment of the present invention.

FIG. 2 is a plan view including a partial cross section of an optical head driving device in an optical information recording / reproducing device of an embodiment of the present invention.

FIG. 3 is a front view including a partial cross section of FIG. 2 seen from the x-axis direction.

FIG. 4 is a left side view of FIG. 2 viewed from the −y axis direction.

FIG. 5 is a detailed view of a fixed roller.

FIG. 6 is a plan view of a preload mechanism portion.

FIG. 7 is a front view of a preload mechanism portion.

FIG. 8 is an enlarged view of an engaging portion of a guide shaft, a fixed roller, and a preload roller.

9 is a detailed view of the linear tracking servo motor seen from the y-axis direction in FIG.

FIG. 10 is another embodiment of the present invention.

11 is an enlarged view of the engaging portions of the guide shaft, the fixed roller, and the preload roller in FIG.

FIG. 12 is a partially sectional front view showing another embodiment of the present invention.

FIG. 13 is a plan view including a partial cross section of an optical head driving device in an optical information recording / reproducing device of another embodiment of the present invention.

FIG. 14 is a front view including a partial cross section of FIG. 13 viewed from the x-axis direction.

FIG. 15 is an enlarged view of an engaging portion of a guide shaft and a fixed roller.

FIG. 16 is a rear view of the optical head housing.

FIG. 17 is a diagram showing another embodiment of the present invention.

FIG. 18 is a diagram showing another embodiment of the present invention.

FIG. 19 is a diagram showing another embodiment.

FIG. 20 is another embodiment of the present invention.

FIG. 21 is another embodiment of the present invention.

FIG. 22 is a diagram showing another embodiment of the present invention.

23 is an enlarged view of the guide shaft and the engaging portion of the fixed roller of the embodiment of FIG. 22.

FIG. 24 is a front view of another embodiment of the present invention.

FIG. 25 is a rear view of the embodiment of FIG. 24.

FIG. 26 is a diagram including a partial cross section of a magnetic circuit portion in the embodiment of FIG. 24.

[Explanation of symbols]

1 Information Recording Optical Disk 2 Sub Base 3 Disk Drive Motor 4 Optical Head 5 Tracking Linear Servo Motor 6 Linear Encoder 7 Objective Lens 8 Objective Lens Actuator 9 System Control Microprocessor 10 Servo Control Circuit 11 Tracking Linear Servo Motor Driver 12 Preamplifier 13 Signal Processing Circuit 14 Objective Lens Actuator Focus Coil Driver 15 Objective Lens Actuator Track Coil Driver 16 Disk Motor Driver 17 Semiconductor Laser Driver 18 First Guide Axis 19 Second Guide Axis 20 Guide Axis Press 21 Screw 22 Fixed Roller 23 Axis 24 Preload Roller 25 Fixed Roller 26 Preload spring 27 Hole 28 Screw 29 First guide shaft 18 and fixed roller 25 contact point 30 First The center of the id shaft 31 31 The contact point between the first guide shaft 18 and the preload roller 24 32 The contact point between the second guide shaft 19 and the fixed roller 22 33 The center of the second guide shaft 19 34 The second guide shaft 19 and the fixed roller 22 Contact point 35 Bobbin 36 Drive coil 37 Center yoke 38 Outer yoke 39 Magnet 40 Screw 41 Screw 42 Rubber damper 43 Thrust generation surface 44 Thrust generation surface 45 Thrust center line 46 Optical center of gravity 47 Disc cartridge 48 Fixed roller 49 Preload roller 50 Pitching optical Head orientation 51, 52 Guide shaft outer yoke 53 Block 58, 59, 60, 61, 62 Drive coil 71 Magnet 72, 73 Magnet mounting surface 74 Adsorbent

Claims (4)

[Claims] 1. A disc for recording information, a rotation driving device for the disc, an optical head for supporting an objective lens and optical means for recording or reading information on the disc, a base for supporting the optical head, and the optical unit. A permanent magnet for guide preload and a magnetic body for guide preload provided on the head and the base so as to face each other, and a course actuator and a guide mechanism portion for moving and positioning the optical head in the radial direction of the disk. An optical information recording / reproducing in which the guide preload permanent magnet and the guide preload magnetic body attract each other, so that the optical head is attracted toward the base and a preload is applied to the guide system. In the apparatus, the optical head includes a plurality of fixed rollers, and first and second guides provided on the base. The permanent magnet and the magnetic body for the guide preload are installed between the shafts, and the permanent magnets and the magnetic bodies are provided on a plane inclined by about 30 to 60 degrees with respect to a plane passing through the axis centerlines of the first and second guide shafts. By pressure,
All of the fixed rollers are pressed against the first and second guide shafts, so that the degree of freedom in the direction other than the positioning direction of the optical head is restricted, and
An optical information recording / reproducing apparatus having a structure in which the assembled optical head can be attached to and detached from the guide system. 2. The fixed roller is five in number.
The optical information recording / reproducing apparatus described in 1. 3. The fixed roller according to claim 1, wherein four of the five fixed rollers engage with the second guide shaft, and one of the five fixed rollers engages with the first guide shaft. Optical information recording / reproducing device. 4. A disc for recording information, a rotation driving device for the disc, an optical head for supporting an objective lens and optical means for recording or reading information on the disc, a base for supporting the optical head, and the optical unit. A permanent magnet for guide preload and a magnetic body for guide preload provided on the head and the base so as to face each other, and a course actuator and a guide mechanism portion for moving and positioning the optical head in the radial direction of the disk. An optical information recording / reproducing in which the guide preload permanent magnet and the guide preload magnetic body attract each other, so that the optical head is attracted toward the base and a preload is applied to the guide system. In the device, first and second guide shafts are provided on the base, and four guide shafts engaging with the second guide shaft are provided. In the constant roller, the axial center lines of the two fixed rollers are substantially parallel to the plane that passes through the axial center lines of the first and second guide shafts, and the axial center lines of the remaining two fixed rollers are the first axial lines. One fixed roller that engages with the first guide shaft has a shaft center line that is substantially perpendicular to a plane that passes through the shaft center lines of the first and second guide shafts. The guide preloading permanent magnet and the magnetic body are installed between the first and second guide shafts so as to be substantially parallel to a plane passing through the axis centerline of the shaft. Approximately 30 degrees to 60 degrees with respect to a plane passing through the axis center lines of the first and second guide axes.
All of the fixed rollers are pressed against the first and second guide shafts by the preload generated on the inclined plane, whereby the degree of freedom other than the positioning direction of the optical head is constrained. At the same time, the optical information recording / reproducing apparatus has a structure in which the assembled optical head can be attached to and detached from the guide system.