JPH07110954A - Objective lens drive - Google Patents

Abstract

(57) [Summary] [Purpose] To reduce the number of parts, reduce parts cost and assembly cost, and realize miniaturization. [Structure] A bobbin supporting plate 4 is attached to a frame 1 having upper and lower surfaces opened to form a frame. The bobbin 8 is attached to the elastic support member 13 in the frame body, and installed on the cantilever support portion. Further, the bottom frame 5 having the yoke 16, the magnet 17, and the triangular prism 15 that form a magnetic circuit is fixed to the lower surface of the frame 1.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an objective lens driving device applied to an optical disk drive, a magneto-optical disk drive or the like and applied to an information device for recording or reproducing information by an optical pickup system.

[0002]

2. Description of the Related Art As one of the technologies of this type,
There is an objective lens driving device described in Japanese Patent No. 52815. According to the device described in this publication, the damper portion of the linear elastic support member is inserted into the hole formed in the movable member and / or the fixed member to perform positioning, thereby positioning these members easily and accurately. This makes it possible to significantly simplify the assembly work.

[0003]

[Problems to be Solved by the Invention]
As shown in Japanese Unexamined Patent Publication (Kokai) No. -52815, a yoke portion and a movable member are generally attached to a base member. However, in such a configuration, the thickness of the base member is inevitably necessary, and it is difficult to downsize the entire drive device, particularly in the height direction.

It is an object of the present invention to solve the above problems, to reduce the number of parts, to reduce the parts cost and the assembling cost, and to provide an objective lens driving device which is downsized.

[0005]

In order to achieve the above object, the present invention provides an objective lens for forming a light spot on an information recording medium, and a movable member for holding the objective lens.
An elastic support member having a damper member for supporting the movable member at one end, a support body supporting the other end of the elastic support member, and a magnetic circuit for applying thrust to the movable member in the focusing direction and the tracking direction. And a drive means for moving the support in the seek direction, wherein the support is a frame body having upper and lower surfaces opened in the optical axis direction of the objective lens, and the objective lens is oriented in the upper surface direction of the frame body. The bottom frame which fixes the movable member in the frame body, and further comprises, on the lower surface of the frame body, a yoke member forming the magnetic circuit, a magnet member, and an optical path changing means for deflecting light toward the objective lens. It is characterized in that it is fixed.

Further, protrusions are provided in the fixing portion of the elastic supporting member on the movable member side and the fixing portion of the elastic supporting member on the frame body side, and holes are formed at both ends of the elastic supporting member so as to fit into the protrusions. It is characterized by

Further, the optical path changing means is a triangular prism,
A plurality of windows are provided on the outer peripheral portion of the adhesion surface of the triangular prism of the bottom frame, and the adhesion surface is held by at least two supporting portions.

Further, the present invention is characterized in that a magnet is embedded in the frame body surface facing the tracking coil provided on the movable member.

Further, the optical path changing means is a triangular prism,
The triangular prism adhesive surface of the bottom frame is tilted at a slight angle with respect to the optical axis direction of the objective lens, and the frame body is provided with an adjusting screw that abuts against the rear surface of the adhesive surface.

[0010]

Since the frame body serves as both the support for the movable member and the carriage for the seek movement, for example, the insulating plate and the base member provided in the conventional objective lens driving device are unnecessary, and the number of parts is increased. Can be reduced
Assemblability is improved, and component cost and assembly cost can be reduced.

Further, since the movable member is positioned by fitting the projections into the holes at both ends of the elastic supporting member, the assembling work of the elastic supporting member becomes easy.

Since a plurality of windows are provided on the outer peripheral portion of the triangular prism bonding surface of the bottom frame, it becomes difficult for force to act on the triangular prism bonding surface from the outside. As a result, a good light spot can be formed on the information recording medium, and stable information pickup becomes possible.

Further, it is possible to reduce at least a part of the yoke portion provided in the conventional objective lens driving device, and it is possible to reduce the size of the frame body.

Further, since the inclination of the triangular prism in the tracking direction can be easily adjusted, it is not necessary to make the accuracy of the triangular prism bonding surface highly accurate, and the cost can be reduced accordingly.

[0015]

Embodiments of the present invention will now be described in detail with reference to the drawings.

FIG. 1 is a partially broken exploded perspective view showing the structure and constituent members of the first embodiment of the present invention. Reference numeral 1 is a U-shaped frame, 2 is a seek coil, and 3 is a seek coil. A side plate supporting the seek coil 2 is shown.
3 is screwed and fixed to the opening and the back surface of the frame 1 from the outside. Reference numeral 4 denotes a bobbin supporting plate provided in the frame 1 in parallel with the side plate 3, and 5 denotes a bottom frame installed in the lower opening of the frame 1. As shown in FIG. 1, a frame body is constituted by the frame 1 and the bobbin supporting plate 4, and further, the frame 1, the seek coil 2, the side plates 3 and 3, the bobbin supporting plate 4, and the bottom frame 5
A box-shaped carriage 6 for moving an objective lens, which will be described later, is formed.

Reference numeral 7 is an objective lens, and 8 is an objective lens 7 in the center.
A bobbin that is a movable member that holds the
Is arranged in the carriage 6 with the objective lens 7 facing upward. Reference numeral 9 denotes a focusing coil wound around the bobbin 8, and 10 denotes a tracking coil attached to the surface of the focusing coil 9. The tracking coil 10 is positioned so as to face the back surface of the frame 1 and the bobbin supporting plate 4. . 11 is the frame 1 from the collar of the bobbin 8.
4 shows a fixing portion of an elastic supporting member, which will be described later, extending to the side surface side of the fixing portion. Further, the fixed portion 11 is provided with a protrusion 11a. Corresponding to the protrusion 11a, the bobbin supporting plate 4 is also provided with protrusions 4a on the upper and lower sides of the side surface of the frame 1. Reference numeral 12 denotes a yoke hole which is a through hole provided on both sides of the objective lens 7 in the bobbin 8.

Reference numeral 13 denotes a leaf spring-shaped elastic support member. The elastic support member 13 includes an elongated plate-shaped elastic portion 13a, mounting portions 13b formed at both ends of the elastic portion 13a, and the mounting portion 13b.
It is composed of a hole 13c formed on the surface. Also, 1
Reference numeral 4 denotes a damper attached to the elastic portion 13a of the elastic support member 13. In the elastic supporting member 13 configured as described above, the hole 13c of the one mounting portion 13b is fitted to the protrusion 11a of the bobbin 8, and U
One end of the elastic supporting member 13 is fixed to the bobbin 8 by V bonding, and the hole 13c of the other mounting portion 13b is fitted into the protrusion 4a of the bobbin supporting plate 4. Similarly, another elastic supporting member 13 is bonded by UV bonding. The end is fixed to the bobbin support plate 4. That is, the elastic support member 13 supports the bobbin 8 in a cantilevered manner with four bobbins 8.

Reference numeral 15 indicates a triangular prism installed on the bottom frame 5, 16 indicates U-shaped yokes installed on both sides of the triangular prism 15, and the yoke 16 is an inner yoke 16a standing on the triangular prism 15 side. And an outer yoke 16b standing upright on the outside. Reference numeral 17 denotes a magnet, which is fixed to the surface of the outer yoke 16b facing the inner yoke 16a.

When the bottom frame 5 is screwed and fixed to the lower surface of the frame 1, the triangular prism 15 is located directly below the objective lens 7 and the inner yoke 16a is formed in the yoke hole 1.
The magnet 17 is loosely fitted in the 2 and 12, and the magnet 17 is the tracking coil 10.
To face. The focusing coil 9, the tracking coil 10, the yoke 16, and the magnet 17 constitute a magnetic circuit that generates thrust for moving the bobbin 8 in the focusing direction and the tracking direction.

Reference numeral 18 designates a port for collecting parallel light from a light source (not shown) provided on one side surface of the frame 1, and 19 is provided on both side surfaces of the frame 1 on the side of the side opening portion, and the oiles. A receiving shaft of a seek shaft (not shown) made of a metal material or the like is shown. The parallel light from the light source (not shown) passes through the light collecting port 18, is deflected by the triangular prism 15, and enters the objective lens 7. The objective lens 7 focuses the collimated parallel light,
A light spot is formed on an optical disc (not shown) which is an information recording medium (not shown). Further, the reflected light from the optical disk (not shown) is the objective lens 7, the triangular prism 15, the light collecting port.
It is led via 18 to a detection means (not shown).

FIG. 2 is a perspective view showing the mounting structure of the triangular prism, in which 20 is an adhesive surface, 21 is a window formed by penetrating the bottom frame 5 in three circular arcs on the outer periphery of the adhesive surface 20, and 22 is an adhesive surface. The support part which connects 20 and the bottom frame 5 main body is shown, and this support part 22 is formed between the windows 21 and 21. That is, the triangular prism 15 is bonded on the bonding surface 20 and is supported by the three supporting portions 22.

FIG. 3 is a perspective view showing the structure of the elastic supporting member before supporting the bobbin, and 23 is the two elastic supporting members 13
Is a pair of connecting members, and the connecting member 23 is
One end and the other end of the two elastic support members 13 are connected to each other at their mounting portions 13b, and as a whole, a rectangular shape is formed as shown in FIG.

FIG. 4 is a perspective view showing a bobbin positioning jig for fixing the bobbin at a predetermined position when fixing the elastic support member to the bobbin, and 24 is a bobbin positioning jig. The bobbin positioning jig 24 is composed of an I-shaped upper jig 24a and an L-shaped lower jig 24b, and has a U-shape.
A through hole 24c is provided at one end of the upper jig 24a. On the other hand, an upper positioning pin 24d that abuts on the bobbin 8 is provided on the other end portion on the surface facing the lower jig 24b. Further, a fixed knob 24e is provided at the other end, a rotary shaft 24f of the fixed knob 24e projects from the center of the upper positioning pin 24d, and a male screw 24g is further provided at the tip of the rotary shaft 24f. .

Further, a lower positioning pin 24h facing the upper positioning pin 24d is provided on the surface of the lower jig 24b facing the upper jig 24a.
Is provided with a stopper 24i for the bobbin 8, and a fixing piece 24j for holding the bobbin support plate 4 between the stopper 24i and the side surface of the lower jig 24b is provided upright on the side adjacent to the stopper 24i. . A female screw 24k is formed at the center of the lower positioning pin 24h.
Further, a pin 24l fitted in the through hole 24c is provided upright on the upper side surface of the lower jig 24b. Furthermore, a fixing screw 24m for fixing the lower jig 24b to the bobbin supporting plate 4 is provided on the side surface of the lower jig 24b.

FIG. 5 shows the bobbin 8 by the bobbin positioning jig 24.
FIG. 6 is a perspective view showing a state in which the elastic support member 13 is attached while holding the. Hereinafter, the elastic support member will be described with reference to FIGS. 4 and 5.
The attachment of 13 will be described.

First, the fixing piece 24j is attached below the bobbin supporting plate 4, and the lower jig 24b is fixed to the bobbin supporting plate 4 with the fixing screw 24m. Next, the bobbin 8 to which each coil is attached is placed on the lower positioning pin 24h, and while the male screw 24g is passed through the central hole (not shown) of the bobbin 8, the through hole 24c is fitted to the pin 24l to set the upper jig 24a. Attach to the lower jig 24b. Then, the bobbin 8 is fixed at a predetermined position by rotating the fixing knob 24e to screw the male screw 24g into the female screw 24k.

After fixing the bobbin 8, a pair of elastic supporting members 13 shown in FIG. 2 are placed from above and adhered by UV adhesion or the like.
After the adhesion, the elastic support member 13 is fixed by cutting the connecting member 23. Further, the frame 1 is turned over, the pair of elastic support members 13 are assembled in the same manner, and the connecting member 23 is cut, so that the elastic support members 13 are fixed at all four positions.

Next, the function and effect will be described.

According to the above-described embodiment, since the carriage 6 has the function as the base of the objective lens driving device and the function as the carriage at the time of seek movement, it has been generally used in the past, for example, the actual one. Members such as a base and an insulating plate, which are found in the objective lens driving device described in Japanese Patent Publication No. 4-52815, are not necessary. Therefore, parts cost and assembly cost can be reduced.

Further, since the base is reduced, the height of the entire drive device can be reduced. 6A and 6B are explanatory views for comparing the heights of the objective lens driving device of this embodiment and a conventional objective lens driving device. FIG. 6A is this embodiment, and FIG. 6B is a conventional example. Indicates. As shown in FIG. 6, in the present embodiment, since there is no base B, it can be designed lower by H in the figure. In actual design, H = 2 ~ 3mm
It is estimated to be equivalent to. By the way, the height of the current drive device becomes thinner day by day, and the one with a height of 24.4 mm (1 inch) is on sale. 2 to 24.4mm for this height
Being able to make the 3mm objective lens drive device thinner makes it possible to reduce the cost of other parts and the assembly cost of the drive device.
It is very advantageous for ease of design.

Further, since the number of parts constituting the objective lens driving device is reduced, the number of bonding and screwing points is also reduced. Therefore, the resonance at that place is reduced,
Resonance harmful to servo can be reduced. In addition, the conventional base material is often made of metal and occupies 20 to 30% of the total weight of the carriage, but since this is eliminated, the weight can be reduced, high-speed access and cost reduction of the seek motor are possible. Becomes

Further, according to the above-described embodiment, since the bobbin 8 is mounted in the frame-shaped frame 1, the frame 1 is turned upside down, so that the elastic support member 13 can be easily mounted below. Furthermore, two elastic support members
Two elastic support members 13 can be positioned at a time by forming a pair of connecting members 23 and fitting a hole 13c of a mounting portion 13b into a protrusion 11a provided on a fixing portion 11 of the bobbin 8. It will be possible. Further, as shown in FIG. 3, the elastic supporting member 13 is connected by two connecting members 23 before attachment and has a rectangular shape, so that the elastic supporting member 13 is kept parallel while maintaining the parallelism. It can be attached to the bobbin 8 and the bobbin support plate 4.

Further, according to the above-mentioned embodiment, a plurality of arcuate windows 21 are provided on the outer periphery of the adhesive surface 20, and the adhesive surface 20 of the triangular prism 15 is held by the three supporting portions 22, so that the carriage 6 Even if the motor runs away and collides with a stopper (not shown), the shock is absorbed by the support portion 22, and the peeling and distortion of the triangular prism 15 can be prevented. Also the bottom frame 5
Bottom frame 5 when attaching to the frame 1
May be deformed. However, the provision of the window 21 makes it difficult for the distortion to be transmitted to the triangular prism 15 even if the bottom frame 5 is deformed. Further, since it is not necessary to increase the accuracy of the mounting surface of the frame 1 or the bottom frame 5, the cost can be reduced.

FIG. 7 is a perspective view showing the structure of a frame which is the main part of another embodiment of the present invention, and 25 and 26 are magnets. In the other embodiment, instead of the outer yokes 16b, 16b and the magnets 17, 17 in the above-mentioned embodiment, a magnet 25 is embedded in the bobbin supporting plate 4, a magnet 26 is embedded in the frame 1, and the magnets 25, 26 are The focusing coil 9 and the tracking coil 10 are opposed to each other.

With this configuration, the outer yoke 16b
Is unnecessary, and the width of the frame 1 (L in the figure) can be shortened accordingly, so that the drive device can also be made lightweight and compact. It should be noted that since the outer yokes 16b and 16b are eliminated, the efficiency of the magnetic field is reduced, but in that respect, it is possible to maintain the performance by strengthening the magnets 25 and 26.

FIG. 8 is a perspective view showing the structure of a mounting portion according to another embodiment of the mounting structure for the triangular prism, and FIG. 9 is a schematic sectional view of FIG. In FIG. 8, 27 is a triangular prism mounting portion formed by cutting and raising a part of the bottom frame 5, 28 is a triangular prism mounting surface, and 29 is a triangular prism mounting portion.
The thin-walled part formed at the base of 27 is shown. The thin portion 29 enables the triangular prism mounting portion 27 to swing.

Further, in FIG. 9, reference numeral 30 denotes an adjusting screw installed on the side surface opposite to the side surface having the through hole 24c in the frame 1, and the triangular prism mounting portion 27 is pressed from the rear side by the adjusting screw 30. The triangular prism mounting surface 28 is provided so as to be tilted slightly rearward from the optical axis direction of the objective lens 7 (see FIG. 1), and the triangular prism 15 is bonded to the triangular prism mounting surface 28 by a jig (not shown). To be done. Reference numeral 31 denotes a collimator that serves as an adjustment jig for adjusting the angle of the triangular prism 15.

Next, the adjustment of the triangular prism 15 will be described. As shown in FIG. 9, first, the collimator 31 is arranged so that the optical axis of the collimator 31 is orthogonal to the parallel light from the light source.
Set up. Next, the triangular prism 15 is set at the intersection of the parallel light and the optical axis of the collimator, and the triangular prism 15 is bonded to the triangular prism mounting surface 28. Then, while monitoring the collimator 31, the angle of the triangular prism 15 is adjusted by the adjusting screw 30.

With such a structure, the inclination of the triangular prism 15 in the tracking direction can be easily adjusted, so that it is not necessary to bond the triangular prism 15 with high precision, and the cost of the carriage 6 can be reduced. Further, since the triangular prism 15 can be lowered by the thickness of the bottom frame 5, the carriage 6 can be downsized.

[0041]

According to the present invention constructed as described above, the following effects can be obtained.

According to the structure of claim 1, the carriage has a function as a base of the objective lens driving device and a function as a carriage at the time of seek movement. It eliminates the need for members such as a metal plate and an insulating plate. Therefore, parts cost and assembly cost can be reduced. Further, since the base is reduced, the height of the entire drive device can be reduced.

Further, since the number of parts constituting the objective lens driving device is reduced, the number of bonding and screwing points is also reduced. Therefore, the resonance at that place is reduced,
Resonance harmful to servo can be reduced. further,
Conventionally, most of the materials of the base are made of metal and occupy 20 to 30% of the weight of the entire carriage. However, since this is eliminated, the weight can be reduced, and high-speed access and high-speed seek can be realized.

According to the second aspect of the invention, the elastic support member can be easily assembled, the assembly cost can be reduced, and the reliability can be improved.

According to the third aspect of the invention, even if the carriage runs out of control and collides with a stopper or the like, the shock is absorbed by the supporting portion, so that peeling or distortion of the triangular prism can be prevented. Further, even if the carriage is deformed during assembly or due to heat or the like, the distortion is less likely to be transmitted to the triangular prism. Therefore, a good light spot can be obtained, stable information pickup can be performed, and reliability of the drive device is improved.

According to the structure of claim 4, the size of the carriage can be made compact, and the drive device can be made compact.

According to the fifth aspect of the present invention, the inclination of the triangular prism in the tracking direction can be easily adjusted, so that it is not necessary to highly accurately adhere the triangular prism, and the cost of the carriage can be reduced. Further, since the triangular prism can be lowered by the thickness of the bottom frame, the carriage can be downsized.

[Brief description of drawings]

FIG. 1 is an exploded perspective view showing a configuration and a constituent member of a first embodiment of the present invention, which is partially broken.

FIG. 2 is a perspective view showing a mounting structure of a triangular prism.

FIG. 3 is a perspective view showing a structure of an elastic support member before supporting a bobbin.

FIG. 4 is a perspective view showing a configuration of a bobbin positioning jig for fixing the bobbin at a predetermined position when fixing the elastic support member to the bobbin.

FIG. 5 is a perspective view showing a state in which a bobbin is held by a bobbin positioning jig and an elastic supporting member is attached.

FIG. 6 is an explanatory diagram for comparing the heights of the objective lens driving device of the present embodiment and a conventional objective lens driving device.

FIG. 7 is a perspective view showing a configuration of a frame which is a main part of another embodiment of the present invention.

FIG. 8 is a perspective view showing a configuration of a mounting portion according to another embodiment of the mounting structure for the triangular prism.

9 is a schematic cross-sectional view of FIG.

[Explanation of symbols]

1 ... frame, 2 ... seek coil, 3 ... side plate,
4 ... Bobbin support plate, 4a ... Protrusion, 5 ... Bottom frame, 6 ... Carriage, 7 ... Objective lens, 8 ... Bobbin, 9 ... Focusing coil, 10 ... Tracking coil, 11 ... Fixed part, 11a ... Protrusion, 12 ... Yoke Hole, 13 ... elastic support member, 13a ... elastic part, 13b ... mounting part, 13c ... hole, 14 ... damper, 15 ... triangular prism,
16 ... Yoke, 16a ... Inner yoke, 16b ... Outer yoke, 1
7, 25, 26 ... Magnet, 18 ... Daylight entrance, 19 ... Receiving shaft, 2
0 ... Adhesive surface, 21 ... Window, 22 ... Supporting part, 23 ... Coupling member, 24 ... Bobbin positioning jig, 24a ... Upper jig, 24b
… Lower jig, 24c… Through hole, 24d… Upper positioning pin,
24e… Fixed knob, 24f… Rotating shaft, 24g… Male screw, 24h… Lower positioning pin, 24i… Rotation stop, 24j…
Fixing piece, 24k… female screw, 24l… pin, 24m… fixing screw, 27… Triangular prism mounting part, 28… Triangular prism mounting surface, 29… Thin part, 30… Adjusting screw, 31… Collimator.

Claims (5)

[Claims] 1. An objective lens for forming a light spot on an information recording medium, and a movable member for holding the objective lens,
An elastic support member having a damper member for supporting the movable member at one end, a support body supporting the other end of the elastic support member, and a magnetic circuit for applying thrust to the movable member in the focusing direction and the tracking direction. A driving means for moving the support in the seek direction, wherein the support is a frame body having upper and lower surfaces opened in the optical axis direction of the objective lens, and the objective lens is oriented in the upper surface direction of the frame body. The bottom frame which fixes the movable member in the frame body, and further comprises, on the lower surface of the frame body, a yoke member forming the magnetic circuit, a magnet member, and an optical path changing means for deflecting light toward the objective lens. An objective lens driving device characterized in that the lens is fixed. 2. A protrusion is provided on a fixed portion of the elastic support member on the movable member side and a fixed portion of the elastic support member on the frame body side, and holes are formed at both ends of the elastic support member so as to be fitted into the protrusion. The objective lens driving device according to claim 1, wherein: 3. The optical path changing means is a triangular prism, a plurality of windows are provided on an outer peripheral portion of the triangular prism adhesive surface of the bottom frame, and the adhesive surface is held by at least two supporting portions. 1. The objective lens driving device according to 1. 4. The objective lens driving device according to claim 1, wherein a magnet is embedded in a surface of the frame body facing the tracking coil provided on the movable member. 5. The triangular prism is used as the optical path changing means, the triangular prism adhesive surface of the bottom frame is tilted by a slight angle with respect to the optical axis direction of the objective lens, and an adjusting screw for contacting the rear surface of the adhesive surface is provided on the frame body. The objective lens driving device according to claim 1, wherein: