JP2747385B2 - Objective lens support device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an objective lens supporting device for an optical pickup used in an optical information recording / reproducing device.

[0002]

2. Description of the Related Art Conventionally, in an optical pickup generally used in an optical information recording / reproducing apparatus, a light beam is focused on a recording surface of an optical disk through an objective lens. It is mounted on an objective lens driving device that is controlled in accordance with the amount of change in detection of reflected light from the optical disc so that the focused light sequentially traces a predetermined track on the recording surface of the optical disc.

The objective lens in the objective lens driving device has two directions: an optical axis direction, that is, a focus direction perpendicular to the recording surface of the optical disk, and a direction perpendicular to the optical axis, that is, a tracking direction parallel to the recording surface of the optical disk. The driving in the direction is performed.

[0004] In the above case, it is necessary to drive the objective lens without causing an inclination in the optical axis direction of the objective lens. Therefore, the objective lens is driven by a joint whose part in the focus direction is locally thinned. Some are configured to be performed by a parallel link mechanism, and are supported by a support for driving an objective lens. The support has a thin, flexible portion at the center of rotation where the objective lens can rotate in the tracking direction.

On the other hand, adjustment of the optical pickup is performed such that the objective lens is in an optimal state with respect to the optical axis when the objective lens is fixed to the lens holder. In this adjusted state, it is desirable that the optical axis of the objective lens does not change under any high or low temperature environment. However, an actuator employing a resin-molded support for driving the objective lens requires only assembling workability and low cost. Although there are many advantages in this respect, a change in the optical axis of the objective lens due to temperature is a major weak point.

Particularly in a high-temperature environment, the hinge portion acting as a parallel link mechanism in the focus direction or a portion locally thinned so as to be rotatable in the tracking direction is often deformed by a high temperature, and is subjected to a standing test at a high temperature. Is performed, the performance of the optical pickup is deteriorated in the state described below.

That is, when the pickup in an appropriate posture with respect to the optical axis of the objective lens is left in a high temperature state, the thin hinge portion is locally softened and hangs down due to the weight of the lens holder including the coil and the lens. State
A part of the lower surface of the lens holder contacts the base substrate or the like. If the lens holder is left as it is, the lower surface of the lens holder comes into close contact with the surface of the base substrate.

At this time, the objective lens is adjusted with respect to the optical axis, but there is a deviation from the surface of the base substrate due to variations in assembling processing and the like. When the lens holder is lifted with the thin hinge part returning to its original hardness, the lens holder will be in a position different from the position before the high-temperature storage test, and the performance will be significantly deteriorated optically. It is eager to reduce.

[0009]

A lens driving support including a parallel link member made of a molded resin in a conventional objective lens support device has good workability in assembly and is low in cost, but the parallel link due to high temperature conditions. The members and the like are deformed and the performance is remarkably deteriorated optically.

[0010]

An objective lens supporting device SUMMARY OF THE INVENTION The present invention, in order to solve the above problems, the invention of claim 1, wherein
Is a swinging part, a supporting part, and a pair of connecting parts between the swinging part and the supporting part.
Arranges joints and forms a parallelogram and swings
Part and connecting part and supporting part and connecting part via hinge
To form a parallel link, and swing
Attach the objective lens to the base and attach the support to the base substrate
Molding the fixed lens drive support with resin
Focus lens with respect to the base substrate
In an objective lens supporting device capable of being displaced in the
At least one side of the connecting portion is made of a spring material.
The plate is arranged and mounted over the connecting portion and the support portion .

[0011]

[Action] objective lens supporting device according to the invention, the connecting portion
A holding plate made of a spring material is arranged and mounted over the support portion.
The device itself in a high temperature condition.
When the thin hinge part is softened locally
Does not fall down due to the weight of the objective lens, etc.
Therefore, it becomes high temperature state and the thin hinge part
Thin hinge part at normal temperature or low temperature after softening
If the lens returns to its original hardness,
Can be maintained.

[0012]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of an objective lens supporting apparatus according to the present invention.

First, the schematic structure of an optical information recording / reproducing apparatus incorporating an objective lens supporting apparatus according to the present invention will be described with reference to FIG. A motor 2 for irradiating the optical disc 1 with a laser beam,
And an optical pickup 3 for taking in reflected light from the optical pickup. The pickup 3 has a laser light source 4, a deflecting mirror 5, and an objective lens 6. The laser light source 4 and the deflecting mirror 5 are disposed in a housing 7, while the objective lens 6 is It is positioned on the optical path between the optical disk 1 and the optical disk 1 and is held by an objective lens driving device 8 described later. The optical pickup 3 is moved by a feed mechanism 9 provided with a drive means such as a linear motor in a direction parallel to the recording surface 1a of the optical disk 1 and in a tracking direction perpendicular to the track.

Next, regarding the objective lens supporting device,
A description will be given based on FIGS. The housing of the objective lens driving device 8 has a base plate 11 having a substantially flat plate shape, a part of which is bent and a through hole 10 is formed at the tip, and a through hole 12 at a portion of the base substrate 11 facing the through hole 10. The cover 13 is formed by perforating the cover 13 and the cover 13 is fitted to the base substrate 11. On the base substrate 11, the supporting portion 14 ′ of the lens driving support 14 is mounted on the opposite side of the through hole 10 with a screw or the like. Hinges 16, 16 and 1 which are locally thin and flexible between the supporting portion 14 'and the swinging portion 15
A plate-like link portion (connecting portion) 18 is provided via 7, 7 and hinges 19, 19 and 19 are similarly attached to the support portion 14 'and the swinging portion 15 so as to keep the link portion 18 in a parallel state at a required interval. A plate-like link portion (connection portion) 21 is provided via 20, 20 to constitute a link mechanism portion.

The oscillating portion 15 is provided with a lens holder mounting portion 23 through a radial hinge 22 which is locally thin and has flexibility in a direction parallel to the optical axis of the objective lens 6. The lens driving support 14 including the support portion 14 ', the link portions 18 and 21, and the swing portion 15 constitutes a link mechanism portion by an integrally molded resin product. A lens holder 25 having a through hole 24 is mounted on the lens holder mounting portion 23, and the objective lens 6 is mounted on the cover 13 side of the through hole 24 so that the optical axis of the objective lens 6 and the base substrate 11 are transparent. The center of the hole 10 and the center of the cover 13 are arranged substantially on a straight line, and form an optical path through which the laser beam passes.

The yokes 26, 2 are arranged on the other side of the base substrate 11 from the outside so as to form a pair.
6 ', magnets 27, 27' and yokes 28, 28 'are arranged side by side. Focus coils 29, 29' are wound around the yokes 28, 28 ', respectively, and mounted on a part of the lens holder 25. Between the yoke 26 and the yoke 28 and between the yoke 26 'and the yoke 28'
A pair of tracking coils 30,
Attach 30 and 30 ', 30'.

When the focus coils 29, 29 'are energized, an electromagnetic force is generated in the lens holder 25 in a direction perpendicular to the plane of FIG. 2, that is, in a direction parallel to the optical axis of the objective lens 6 in FIG. The lens 6 is swung in the focus direction by the link mechanism.

On the other hand, when the tracking coils 30 and 30 'are energized, an electromagnetic force is generated in the direction of rotating the lens holder 25 about the radial hinge 22 of the oscillating portion 15 while keeping the lens holder 25 in the horizontal state. 6 swings in the tracking direction.

Next, in the objective lens supporting device as described above, in order to withstand a use test in a high temperature state or a standing test in a high temperature state, FIG. in the holding plate 31 of the cover 13 side of a spring member having the shape shown by oblique lines, mounted fixed in熔着like in the mounting portions 32, 33 and 3 6. The holding plate 3
Similarly to 1, the holding plate 34 is attached between the support portion 14 'and the plate-like link portion 21 by welding or the like. In the case where the objective lens driving device is always used in a fixed direction, only one of the cover-side holding plate 31 and the base-side holding plate 34 may be used. Also, the mounting portion 3 of the holding plates 31 and 34
When the lens holder 25 including the objective lens 6 moves in the focusing direction, the hinges 16 and 19 are arranged by placing the lens 3 as close to the hinges 16 and 19 as possible.
In addition, the difference (deviation) between the respective bending center points due to the difference in the radius of curvature (R) at which the holding plates 31 and 34 bend can be reduced.

[0020] Furthermore, the link portion 18 between the fitting 3 6 and the respective mounting portions 32, 33 of the holding plate 31 and 34,
By providing the loop portion 35 curved on the 21 surface,
The difference in the radius of curvature (R) at which the hinges 16, 19 and the holding plates 31, 34 bend can be absorbed by making the holding plates 31, 34 stretchable in the longitudinal direction. The shapes of the holding plates 31 and 34 have the same function, and may be the same or different.

Since the holding plates 31 and 34 are attached to both the link portions 18 and 21 of the link mechanism, respectively, the resin-molded link portions 18 and 21 and the holding plates 31 and 34 made of a metal spring member are connected. The difference in expansion and contraction due to temperature change is almost dependent on the expansion and contraction of the holding plates 31 and 34 made of a metal plate having a small expansion and contraction ratio. The elongation in the vertical direction is the same, and it is possible to prevent the optical axis of the objective lens 6 from being tilted without the link portions 18 and 21 being differently deformed.

FIG. 3 shows a state when the objective lens supporting device is not operated, while FIGS. 4 and 5 show a state when the objective lens supporting device is operated in the focus direction.

Next, a second embodiment of the objective lens supporting device will be described with reference to FIGS.

In FIG. 6, the lens driving support 14 including the support portion 14 ', the link portions 18, 21 and the swing portion 15 is the same as that of the first embodiment. ′ Is provided with a projection 41 for fixing a holding member described below.

A holding member 42 made of a spring material for holding the link portions 18 and 21 is provided with a holding portion 43 having a U-shaped cross section so as to hold the support portion 14 'from outside. The upper and lower ends of 43 have holding pieces 44 and 45. A through hole 46 is provided at the center of the holding portion 43 so as to correspond to the projection 41 of the support portion 14 '. The holding pieces 44 and 45 include:
Arc-shaped bent portions 47 and 48 are provided at portions of the lens driving support 14 facing the hinges 16 and 19, and
The tips 49 and 50 are warped outward.

The support portion 1 of the lens driving support 14
4 'is inserted into the through hole 46 of the holding member 42, and the holding member 42 is mounted on the lens driving support 14, as shown in FIG. The drive device 8 is fixed to the base substrate 11 of the housing by screws or the like.

Since the upper and lower holding pieces 44 and 45 of the spring member are integrally formed via the holding portion 43, the holding member 42 is attached to the lens driving support 14 by the holding member 4.
2 can be inserted and attached.

The holding piece 4 of the holding member 42
The bent portions 47 and 48 of the hinges 4 and 45 are connected to the hinge 1 respectively.
6 and 19, and the hinges 16 and 19 have an arc shape with the center being substantially at the center.
As shown in FIG. 8, the difference between the length of the lens driving support 14 during the driving in the focus direction, that is, the substantial length changed by the link mechanism and the length of the holding member 42 can be absorbed.

Further, the pressing force of the holding pieces 44 and 45 of the holding member 42 to the link portions 18 and 21 is pressed in the direction shown by the two-dot chain line in FIG. 7, and the amount of deflection of this spring portion is It is desirable that the distance be equal to or larger than the movement amount of the link portions 18 and 21 in the focus direction. Since the present invention is configured as described above, even after the high-temperature storage test, the particularly thin hinge portion connected to the parallel link member is not deformed, so that the lens holder is not tilted, and the objective lens is not tilted. The normal state where the optical axis is perpendicular to the inclined surface of the optical disk can be maintained.

[0030]

According to the first aspect, the connecting portion and the supporting portion are provided.
The holding plate made of spring material is arranged and mounted over
And leaving the device in a hot state
Even if the thin hinge part is softened,
It does not drop downward due to the weight of the
Because of the high temperature, the thin hinge part softens
At normal temperature or low temperature, the thin hinge part is the original hardness
When returning to, keep the objective lens in the same position.
Optical performance and assembly workability
A low cost objective lens supporting device with excellent quality
can do.

According to the second aspect, when the lens holder 25 including the objective lens 6 moves in the focusing direction, the difference between the respective bending center points due to the difference in the radius of curvature at which the hinges 16, 19 and the holding plates 31, 34 bend. It is possible to drive the link mechanism part smoothly with less.

According to the third aspect, the difference between the bending center points can be absorbed by providing elasticity in the longitudinal direction of the holding plates 31, 34, and the link mechanism can be driven more smoothly.

In the fourth aspect, the lens holder 25
The lower surface of the lens holder 25 does not adhere to the surface of the base substrate 11 so that the holding member 42 can be inserted and mounted on the lens driving support 14.
There is no need to attach the distal end of the 45 to the link portions 18 and 21 by welding or the like, and the assembling work can be simplified.

According to the fifth aspect, the difference between the length of the lens driving support member during driving in the focus direction, that is, the substantial length changed by the link mechanism and the length of the holding member is absorbed. Can absorb the difference in the expansion coefficient.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of an example of an optical information recording / reproducing apparatus incorporating an objective lens support device of the present invention.

FIG. 2 is a plan view when a cover of the objective lens supporting device according to the present invention is removed.

FIG. 3 is a side view of the central cross section of the objective lens supporting device according to the present invention when it is not operated.

FIG. 4 is a side view of the center section when the lens holder is moved to the base substrate side in the objective lens supporting device according to the present invention.

FIG. 5 is a central sectional side view when the lens holder is moved to the cover side in the objective lens supporting device according to the present invention.

FIG. 6 is an exploded perspective view of a lens driving support and a holding member in an objective lens supporting device according to another embodiment of the present invention.

FIG. 7 is a side view of a lens driving support in an objective lens supporting device according to another embodiment of the present invention.

FIG. 8 is a side view of a lens driving support when a lens holder moves to a cover side in an objective lens supporting device according to another embodiment of the present invention.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 optical disk 4 laser light source 6 objective lens 8 objective lens driving device 14 lens driving support 15 swinging unit 16, 17, 19, 20 hinge 25 lens holder 31, 34 holding plate 35 holding plate loop 42 holding member 44, 45 Holding piece 47, 48 Bending part of holding piece

Claims (5)

(57) [Claims] 1. A swinging part, a supporting part, and a swinging part and a supporting part.
Arrange the pair of connecting parts so as to form a parallelogram
Together with the swinging part and the connecting part and the supporting part and the connecting part.
To form a parallel link by linking
Attach the objective lens to the swinging part, and
The lens drive support fixed to the base substrate is made of resin.
By molding, the objective lens can be
Objective lens support device that can be displaced in the focusing direction
In at least one side of the connecting portion, a holding member made of a spring material
An objective lens supporting device , wherein a plate is arranged and mounted over a connecting portion and a supporting portion . 2. The holding plate according to claim 1 , further comprising:
Located close to the hinge between the support and the connection
And wherein the the objective lens supporting device according to claim 1. Wherein said holding plate is characterized in that a loop portion that is curved in the consolidated portion plane, an objective lens supporting device according to claim 1. 4. A swinging part, a supporting part, and a swinging part and a supporting part.
Arrange the pair of connecting parts so as to form a parallelogram
Together with the swinging part and the connecting part and the supporting part and the connecting part.
To form a parallel link by linking
Attach the objective lens to the swinging part, and
The lens drive support fixed to the base substrate is made of resin.
By molding, the objective lens can be
Objective lens support device that can be displaced in the focusing direction
In, having holding pieces at both ends of the holding portion for holding the support portion ,
Molded Then Co cross section a substantially U-shaped holding member with a spring member
Then, the holding portion of the holding member is held between the support portion and a pair of holding members .
An objective lens supporting device , wherein holding pieces are respectively positioned on a connecting portion surface. 5. The holding piece of the holding plate or the holding member,
In the part facing the hinge between the support part and the connection part ,
Characterized in that a bent portion of the sushi circle arc straddle the hinge, the objective lens supporting device according to claim 1 or 4.