JP3030989B2 - Optical storage device and method of adjusting angle of objective lens used for the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a structure of a movable optical head of an optical storage device and a method of adjusting an angle of an objective lens.

[0002]

2. Description of the Related Art FIG. 8 shows a side view of a movable optical head of an optical storage device using a conventional separation type optical system in which a light source section and an objective lens section are separated. The objective lens 902, the focus coil 903, and the parallel leaf spring 904 are attached to the bobbin 901 and fixed to the chassis 905. The deformation of the parallel leaf spring 904 allows the objective lens 902 to be displaced in the focus direction 906. 908 was fixed to a chassis 905, and the objective lens 902 was movable in a seek direction 910 by a rolling bearing 909.

The optical storage medium 911 of the objective lens 902
When the objective lens 902 is adhered to the bobbin 901, the angle adjustment with respect to is performed by using a jig, or a mechanism for adjusting the angle is separately required.

[0004]

[0005]

SUMMARY OF THE INVENTION The miniaturization of the optical storage device,
The demand for cost reduction is endless, and a thinner and cheaper mechanism is needed. For this purpose, an effort has been made to reduce the weight of the movable part as much as possible by using a separate optical system.
However, in the prior art shown in FIG. 8, since the objective lens 902 is connected to the chassis 905 via the parallel leaf spring 904, the force generated by the seek coil 907 cannot be directly transmitted to the objective lens 902, and the galvano mirror And other precision actuators are required separately, and the structure is complicated.

[0006] In addition, the size and the weight of the movable part are increased by the rolling bearing, and the cost is also increased.

Therefore, an object of the optical storage device of the present invention is to make it possible to directly control the position of an objective lens and to realize a reduction in size and cost by simplifying the structure.

Conventionally, the step of adhering the objective lens and the step of adjusting the angle are performed simultaneously, so that it is difficult to control unnecessary adhesion of the adhesive by displacing the objective lens for adjusting the angle, or to control the curing speed of the adhesive. It was easy to cause problems such as poor angle adjustment due to this. Alternatively, the weight of the movable part has increased due to the angle adjustment mechanism.

An object of the objective lens angle adjusting method of the present invention is to realize a method in which the bonding step and the angle adjusting step are separated, and the apparatus does not require a special adjusting structure.

[0010]

[0011]

[0012]

An optical storage device according to the present invention comprises:
A movable optical head for performing a focus operation by displacing the objective lens perpendicular to the optical storage medium and performing a seek operation by moving the objective lens parallel to the optical storage medium, wherein the movable optical head has a chassis; Then, an objective lens, a reflective optical element, a focus coil, a seek coil, and a magnetic body are fixed to the chassis, and the focus coil, the seek coil, and the magnetic body are arranged in the same magnetic gap. , An inner yoke, a magnet and an outer yoke, and are disposed at two locations on both sides of the objective lens. The movable optical head moves in the focus direction and seek direction along the side surface of the inner yoke. As well as
The reflective optical element is arranged between the two inner yokes.

In this case, the magnetic material is an iron wire installed in parallel with the optical storage medium, and it is desirable that the movable optical head magnetically levitated by the iron wire be maintained in parallel with the optical storage medium. Alternatively, a small piece of a plurality of magnetic materials placed on a line parallel to the optical storage medium may be used as the magnetic material.

[0014]

Further, the chassis is made of a plastic having self-lubricating properties, and the sliding portion is integrally formed.

Further, the chassis has a metal sliding portion.

Further, the magnetic circuit component parts are coated with a resin having self-lubricating properties.

[0018]

According to the method of adjusting the angle of the objective lens of the optical storage device of the present invention, the focusing operation is performed by holding the objective lens by magnetic levitation and displacing the objective lens vertically with respect to the optical storage medium, and moving the object lens parallel to the optical storage medium to seek. It has a movable optical head for performing operations, and is characterized in that the inclination of the objective lens with respect to the optical storage medium is adjusted by changing the position and angle of a magnetic circuit used for magnetic levitation.

In this case, the magnetic circuit is a magnet or yoke, and it is desirable that the magnet and the yoke be bonded after the angle is adjusted by changing the mounting position and the mounting angle of the magnet or the yoke.

[0021]

[0022]

【Example】

Embodiment 1 FIG. 1A is a front sectional view of a movable optical head and a magnetic circuit in an optical storage device of the present invention, and FIG. 1B is a plan view of a movable optical head and a magnetic circuit in the optical storage device of the present invention. FIG. 1C is a side view of a movable optical head and a magnetic circuit in the optical storage device of the present invention.

The chassis 101 is made of plastic,
An objective lens 102, a plane mirror 103 serving as a reflective optical element,
Focus coils 104 and 105, seek coil 10
6, 107 are directly adhered to each other, and the iron wires 108, 1
09 is indirectly bonded and fixed via a seek coil, and the magnetic gap 1 formed by the inner yokes 110 and 111, the magnets 112 and 113, and the outer yokes 114 and 115.
The focus coils 104 and 105 during
, The effective portions of the seek coils 106 and 107, and the iron wires 108 and 109.

The magnetic field strength distribution in the focus direction 120 of the magnetic gap is strongest near the center of the magnet. The iron wire is most stable when it is located near the center of the magnet where the magnetic field strength is the highest, so that the chassis floats by the magnetic force. At this time, the iron wire tries to be parallel to the magnet. By aligning the center of gravity of the movable optical head with the point of magnetic force applied to the magnetic body , the movable optical head was levitated by an iron wire in a posture parallel to the magnet.

Aluminum plates 118 and 119, which are sliding portions, are fixed to the chassis 101 by an outsert technique. FIG. 2A is a front view of the aluminum plate 118, and FIG. 2B is a plan view. 201, 20 sliding parts
2, 203 and 204, which were mirror-finished. Also, the chamfer 207 is designed to be cheaper to move in the
208, 209, 210, 211, 212, 213, 2
I did 14. In addition, chamfers 215, 216, 217, and 218 were performed so as to be cheap in the seek direction 206.

The shape of the chamfered portion may be finished with a curved surface such as a spherical surface. However, since it is necessary that the dimension A is accurate and it is difficult to wear, the sliding portion has a good flat end.

FIG. 3 is an external view of the movable optical head. The inner surface 302 of the inner yoke 301 is coated with a self-lubricating fluororesin to reduce the coefficient of friction.

(Embodiment 2) FIG. 4 shows another embodiment of the present invention. The chassis is made of self-lubricating plastic,
The inner surface of the inner yoke 401 is mirror-finished. The magnetic bodies 402 and 403 are steel balls and are arranged on a straight line parallel to the magnet. Although not visible in FIG. 4, two steel balls are similarly fixed on the opposite side.

(Embodiment 3) FIG. 5 is a front sectional view of another embodiment of the present invention. The chassis 501 surrounds the inner yokes 502 and 503 and extends into the magnetic gaps 504 and 505 to reinforce the coil. Iron piece 50
6, 507 were directly fixed to the chassis 501. There were four sliding parts.

Reference numeral 508 denotes a printed circuit board, which is fixed to the chassis 501, and leads out wires from each coil. The printed circuit board 508 was wired to the fixed-side circuit board 510 by a stranded wire 509 obtained by twisting a plurality of conductive wires. The stranded wires are used to reduce the resistance due to the wires.

The fixing portion of the stranded wire 509 was protected by using rubber-based adhesives 511 and 512, and the disconnection was prevented.

FIG. 6 is an external view. The other end 601 of the printed circuit board was used as a lock mechanism 602 for preventing the movable optical head from moving when the power was turned off. As a result, the reliability against the impact when the device is carried is improved.

(Embodiment 4) The rotation directions that pose a problem on the aberration of the objective lens are the rolling and pitching of the movable optical head. In the method of holding the movable optical head by magnetic levitation as in the present invention, the tilt of the objective lens can be adjusted by changing the position and angle of the magnetic circuit used for magnetic levitation and adjusting the magnetic field intensity distribution.

As shown in FIG. 7, the position and angle of the jig were changed by adjusting screws 702 and 703 provided on a jig. Similarly, the position and angle of the other magnet were adjusted. Thereby, the pitching direction can be adjusted. In the rolling direction, the clearance between the sliding portion and the inner yoke can be adjusted.

The distance between the optical storage medium and the objective lens can be adjusted by this adjustment.

At this time, the magnet 701 is connected to the outer yoke 704
It is easy to adjust because it is attracted by magnetic force. After adjustment, they were fixed by adhesion.

[0037]

[0038]

[0039]

As described above, according to the present invention, an objective lens, a reflective optical element, a focus coil, a seek coil, and a magnetic body are fixed directly or indirectly to a chassis of a movable optical head. By placing the effective portion and the magnetic body in the same magnetic gap, by moving the movable optical head in both the focus direction and the seek direction along the side surface of the magnetic circuit component that generates the magnetic gap, The movable optical head can be held by magnetic levitation, the frictional force can be extremely reduced, and the objective lens can be driven directly without the intervention of a spring element or backlash. A simple one-stage servo system could be used without the need for a two-stage servo system. In addition, by using the side surfaces of the components of the magnetic circuit as guides in two directions, the focus direction and the seek direction, the structure is simplified, and the size and cost can be reduced.

Further, the movable optical head can be easily made parallel to the optical storage medium by using the magnetic material as an iron wire installed in parallel with the optical storage medium.

Further, by using the magnetic material as a plurality of small pieces of the magnetic material disposed on a line parallel to the optical storage medium, the degree of freedom in design is increased and the holding force of the magnetic levitation can be set to a desired value. .

The mass productivity is improved by using a self-lubricating plastic as the chassis and integrally forming the sliding portion.

The durability was improved by providing a metal sliding portion on the chassis.

Further, by coating the side surface of the magnetic circuit component with a resin having self-lubricating properties, the frictional force could be extremely reduced.

Further, the magnetic gap is made two on the left and right,
Each is composed of an inner yoke, a magnet, and an outer yoke, and by moving the movable optical head along the side surfaces of the two inner yokes, it is well balanced and it is difficult for high-order resonance to occur, and the obtained acceleration is increased and high-speed driving is possible. became.

On the other hand, according to the objective lens adjusting method of the present invention, the step of bonding the objective lens and the step of adjusting the angle can be separated.
Moreover, it is possible to realize that no special adjusting structure is required for the device.

[0047]

[0048]

As described above, the present invention greatly contributes to the development of optical storage.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram of a movable optical head and a magnetic circuit of an optical storage device according to a first embodiment of the present invention. (A) is an explanatory view showing the front, (b) is an explanatory view showing the plane, (c).
It is explanatory drawing which showed the side surface.

FIG. 2 is an explanatory diagram of a sliding portion according to the first embodiment of the present invention. (A) is an explanatory view showing the front, and (b) is an explanatory view showing the plane.

FIG. 3 is an external view of the first embodiment.

FIG. 4 is an external view of a second embodiment.

FIG. 5 is an explanatory diagram showing a front cross section of a third embodiment.

FIG. 6 is an external view of a third embodiment.

FIG. 7 shows a fourth embodiment of the objective lens angle adjusting mechanism according to the present invention;
FIG.

FIG. 8 is an explanatory diagram of a conventional technique.

[Explanation of symbols]

101 501 Chassis 102 902 Objective lens 103 908 Reflective optical element 104 105 903 Focus coil 106 107 907 Seek coil 108 109 402 403 506 506 507 Magnetic body 110 111 301 401 502 503 Inner yoke 112 113 704 Magnet 114 115 116 701 Outer yoke 505 Magnetic gap 118 119 Sliding part 120 205 906 Focusing direction 121 206 910 Seek direction 122 911 Optical storage medium 201 202 203 204 Sliding part 207 208 209 210 211 213 2
14 215 216217 218 Chamfering 302 Self-lubricating plastic coating 508 Printed circuit board 509 Stranded line 510 Fixed circuit board 511 512 Rubber adhesive 601 Other end of printed circuit board 602 Lock mechanism 901 Bobbin 904 Parallel leaf spring 905 Conventional chassis 909 Rolling bearing

──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Tadashi Yamada 3-5-5 Yamato, Suwa-shi, Nagano Seiko Epson Corporation (56) References JP-A-3-130931 (JP, A) JP-A-62 −239336 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) G11B 7/085 G11B 7/08 G11B 7/09 G11B 7/095

Claims (8)

(57) [Claims] 1. An optical storage device having a movable optical head for performing a focus operation by displacing an objective lens perpendicular to an optical storage medium and performing a seek operation by moving the objective lens in parallel with the optical storage medium. The movable optical head has a chassis, and the objective lens, the reflective optical element, the focus coil, the seek coil, and the magnetic body are fixed to the chassis, and the focus coil, the seek coil, and the magnetic body are in the same magnetic gap. Wherein the magnetic gap is composed of an inner yoke, a magnet and an outer yoke, and is further arranged at two locations on both sides of the objective lens, and the movable optical head is And configured to move in a focus direction and a seek direction along a side surface of the inner yoke; An optical storage device, wherein a reflection optical element is disposed between two inner yokes. 2. The optical recording medium according to claim 1, wherein the magnetic body is an iron wire installed in parallel with the optical storage medium, and the movable magnetic head magnetically levitated by the iron wire is maintained in parallel with the optical storage medium. Item 2. The optical storage device according to item 1. 3. The optical recording medium according to claim 1, wherein the magnetic material is a plurality of small pieces of magnetic material disposed on a line parallel to the optical storage medium, and the movable optical head magnetically levitated by the plurality of small pieces of magnetic material. 2. The optical storage device according to claim 1, wherein the optical storage device is maintained in parallel. 4. The optical storage device according to claim 1, wherein said chassis is made of a plastic having a self-lubricating property. 5. The optical storage device according to claim 1, wherein said chassis has a metal sliding portion. 6. The optical storage device according to claim 1, wherein a side face of said inner yoke is coated with a resin having self-lubricating properties. 7. An objective of an optical storage device having a movable optical head that holds a objective lens by magnetic levitation and performs a focus operation by displacing the objective lens vertically with respect to the optical storage medium, and moves in parallel with the optical storage medium to perform a seek operation. In the method for adjusting the angle of a lens, an inclination of the objective lens with respect to the optical storage medium is adjusted by changing a position and an angle of a magnetic circuit used for magnetic levitation. Angle adjustment method. 8. The magnetic circuit according to claim 1, wherein the magnet or the yoke is attached to the magnet or the yoke after adjusting the angle by changing the mounting position and the mounting angle of the magnet or the yoke. 8. The method for adjusting the angle of the objective lens of the optical storage device according to 7.