JP2022034297A - Lens support device - Google Patents

Abstract

To provide a lens support device that has durability and reliably supports a movable part having an increased weight.SOLUTION: A lens support device comprises: a stationary part 12; and a movable part 14 that has a lens and is supported by a support mechanism 16 movably in a direction perpendicular to an optical axis direction of the lens with respect to the stationary part. The support mechanism has suspension wires 18a, 18b, 18c obtained by aggregating a plurality of single lines having elasticity in parallel to each other, first connection parts 20 on the stationary part to which one ends of the suspension wires are connected, and second connection parts 22 on the movable part to which the other ends of the suspension wires are connected. The plurality of single lines of the suspension wires are fixed to each other only at the first connection parts and the second connection parts.SELECTED DRAWING: Figure 1

Description

The present invention relates to a lens support device in a camera module of a mobile phone or the like.

As shown in Patent Document 1 (Japanese Unexamined Patent Publication No. 2018-72776), a small lens support device for use in a camera module of a mobile phone or the like has been developed. In such a small lens support device, a movable portion having a lens is electrically connected to a fixed portion having a circuit board, and the movable portion is configured to be able to move relative to the fixed portion. To enable such electrical connection and relative movement, the movable and fixed parts are supported by elastically deformable conductive suspension wires.

For such suspension wires, "support the lens (moving part) with high accuracy"
, "Has appropriate rigidity (reaction force) for operation with the actuator", "Has durability that can withstand the working environment such as repeated movement of moving parts and impact due to dropping" , "Efficient power supply to moving parts" is required. Especially recently, camera modules such as mobile phones have become more sophisticated (for example, equipped with an optical image stabilization function (OIS)).
As the lens becomes larger and the number of lenses increases, the weight of the movable part to be supported by the suspension wire becomes heavier, and it is required to improve the fatigue durability of the suspension wire.

Therefore, in order to improve various characteristics of the suspension wire, Patent Document 2 (Japanese Patent Laid-Open No. 20)
As shown in Japanese Patent Application Laid-Open No. 03-168229) and Patent Document 3 (Japanese Unexamined Patent Publication No. 2001-273652), various studies have been made on suspension wires.
In the suspension wire described in Patent Document 2, a stranded copper-silver alloy is used in order to reduce secular variation and enable stable signal reading.
Further, the suspension wire described in Patent Document 3 is a suspension wire for mounting on a pickup lens for an optical disk drive. This suspension wire
In order to raise the operating sensitivity in the tracking direction higher than the operating sensitivity in the focusing direction, a plurality of solder-coated wires are bonded and fixed in parallel over the entire length to make the suspension wire lateral (tracking direction). It is described that the spring constant with respect to the vertical direction (focusing direction) is changed.

Japanese Unexamined Patent Publication No. 2018-72776 Japanese Patent Application Laid-Open No. 2003-168229 Japanese Unexamined Patent Publication No. 2001-273652

The conventional single wire suspension wire described in Patent Document 1 has a problem in durability, and there is a problem that if the diameter of the single wire is simply increased, the rigidity (reaction force) of the suspension wire increases too much and the sensitivity of the actuator decreases. ..
Further, in the case of the suspension wires of Patent Documents 2 and 3, a plurality of strands are in close contact with each other and fixed to each other. Therefore, in a broad sense, it is the same as a single track.
In order to increase the durability, there is no choice but to increase the cross-sectional area as in Patent Document 1, and if this cross-sectional area is increased, there is a problem that the rigidity (reaction force) also increases too much.

The present invention has been made to solve the above problems, and an object of the present invention is to provide a lens support device having durability while reliably supporting a movable portion having an increased weight.

In order to achieve the above object, the present invention comprises the following configurations.
That is, the lens support device according to the present invention has a fixed portion and a movable portion that has a lens and is movably supported by a support mechanism in a direction perpendicular to the optical axis direction of the lens with respect to the fixed portion. The support mechanism comprises a suspension wire in which a plurality of elastic wires are assembled in parallel, a first connection portion in the fixing portion to which one end of the suspension wire is connected, and the suspension wire. The other end of the suspension wire has a second connection portion in the movable portion to which the other end of the suspension wire is connected, and the plurality of strands of the suspension wire are the first connection portion and the second connection portion.
It is characterized in that it is fixed to each other only by the connection portion of.

The suspension wire can be configured by assembling two or more and seven or less strands.
The suspension wire is located on the outer periphery and can be arranged so that a straight line connecting the center points of the cross sections of adjacent strands forms a substantially regular polygon.
Of the plurality of strands, at least one strand may be a strand having a material and / or shape different from that of the other strands.

At the first connection portion and the second connection portion, a suspension wire in which the ends of the plurality of strands are integrated can be fixed.
A plating layer of a noble metal or a noble metal alloy can be formed on each surface of the plurality of strands.
The movable portion and the fixed portion can be connected by the suspension wire at a plurality of places.

According to the present invention, it is possible to provide a lens support device having durability while reliably supporting a movable portion having an increased weight.

It is explanatory drawing which shows the outline of the lens support device 10. FIG. 2A is a perspective view showing a specific example of a suspension wire in which a plurality of strands are assembled, and FIG. 2B is a plan view thereof. It is sectional drawing of the strand which formed the plating layer and the coating layer in the conductor part. FIG. 4A is an end view of the suspension wire containing strands of different materials and / or shapes, and FIG. 4B is a perspective view thereof. It is explanatory drawing of the simple model (model A, model B, model C) of a lens support device. It is explanatory drawing which shows the reaction force measurement method. It is a graph which shows the result of the reaction force measurement of the model A, B, C. It is explanatory drawing which shows the bending test method. It is a graph which shows the result of the bending test of models A, B, and C. It is a graph which shows the data which measured the reaction force (rigidity) when 5 kinds of suspension wires were used.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.
FIG. 1 is an explanatory diagram showing an outline of the lens support device 10.
The lens support device 10 is a small lens support device 10 for use in mobile devices such as mobile phones and tablet terminals, and camera modules such as optical pickup devices.
Hereinafter, the lens support device 10 in the camera module of the mobile phone will be described.
The lens support device 10 includes a fixed portion 12 and a movable portion 14. The movable portion 14 has a lens (objective lens: not shown), and is supported by a support mechanism 16 so as to be movable in a direction perpendicular to the optical axis direction of the lens with respect to the fixed portion 12.

As the basic configuration of the lens support device 10, for example, a known mechanism having a camera shake correction function as shown in Japanese Patent Application Laid-Open No. 2018-72776 (Patent Document 1) can be adopted as it is.
That is, although not shown, the movable portion 14 has a lens (objective lens) movably supported in the focusing direction, a magnet for position correction and a focus coil, and a focus coil.
Further, although not shown, the fixing portion 12 supplies power to the position correction coil and the position sensor arranged so as to face the magnet, the position correction coil and the position sensor, and transmits a signal from the position sensor. It has a circuit board having wiring for the purpose and a light receiving element such as a CCD.

The greatest feature of the present embodiment is the configuration of the support mechanism 16 that movably supports the movable portion 14 with respect to the fixed portion 12 in the direction perpendicular to the optical axis direction of the lens.
That is, the support mechanism 16 has suspension wires 18 (18a, 18b, 18c, 18d ... 18d are invisible) that support the fixed portion 12 and the movable portion 14 at these four corners. Then, in the present embodiment, as shown in FIGS. 2A and 2B, each suspension wire 18 is configured as a suspension wire in which a plurality of elastic (for example, 2 to 7) strands 50 are assembled in parallel. It is characterized by being done.
The suspension wire 18 may support and connect the fixed portion 12 and the movable portion 14 not at these four corners but at a plurality of appropriate locations such as three or five locations.

One end of each suspension wire 18 is electrically connected and fixed to the first connection portion 20 on the circuit board in the fixed portion 12, and the other end is the second connection portion 22 in the movable portion 14.
It is electrically connected to and fixed to the focus coil.

As described above, in the present embodiment, each suspension wire 18 is characterized in that a plurality of strands 50 are assembled in parallel.
Parallel means that the plurality of strands 50 are bundled wires, not stranded wires.
Further, assembling means that a plurality of strands 50 may be in contact with each other, but are not fixed and are independently free. That is, each suspension wire 18 is fixed to each other only at both ends of the plurality of strands 50 and only at the first connecting portion 20 and the second connecting portion 22. Since each of the strands 50 of the suspension wire 18 is independent and free in this way, the cross-sectional area of the suspension wire 18 can be increased while maintaining the rigidity (reaction force) of the suspension wire 18 (without increasing the rigidity). , Durability could be improved.

For each suspension wire 18, it is preferable to assemble a plurality of strands 50 having two or more and seven or less wires in relation to handling and rigidity (reaction force). In this case, the rigidity (softness) must be in the required desired range. The factors that affect the rigidity (reaction force) are the material and diameter (thickness) of the wire 50 (wire). In order to increase the durability, it is necessary to increase the cross-sectional area, but as described above, simply thickening one wire to increase the cross-sectional area is sufficient.
Rigidity (reaction force) becomes too large.
In this regard, in the present embodiment, a plurality of strands 50 are assembled in parallel and the strands 50 are formed only at both ends.
By fixing them to each other, it was found that the cross-sectional area can be increased, that is, the durability can be improved while maintaining the rigidity (reaction force) even if a plurality of pieces are assembled.

The number of the strands 50 to be aggregated is preferably 2 to 7 as described above, and particularly preferably about 3 to 5, in relation to (required rigidity (reaction force)). At this time, the suspension wire 18 composed of the plurality of strands 50 is configured in an assembled state as shown in FIGS. 2A and 2B.
When assembling 3 or more and 7 or less strands, as shown in FIG. 2B, the straight line located on the outer circumference and connecting the center points of the cross sections of the adjacent strands is almost a regular polygon. It is preferable to arrange them so as to form a polygon. Specifically, as shown in FIG. 2B, an equilateral triangle, a square, a regular hexagon, or the like is used.
As a result, when the movable portion 14 is translated with respect to the fixed portion 12 (movement in the direction perpendicular to the optical axis of the lens), the load on each strand of each suspension wire 18 acts evenly, and the movable portion 14 can move with respect to the fixed portion 12 in a well-balanced manner.

FIG. 3 is a cross-sectional view showing an example (wire 50a) of the wire 50 used for the suspension wire 18. The strand 50a has a plating layer 52 on the outer periphery of the conductor portion 51, and a coating layer 53 on the outer periphery thereof.
Have.
The conductor portion 51 is a nickel-copper alloy, a zirconium-copper alloy, which has elasticity and is excellent in conductivity.
It is preferable that it is made of a copper alloy such as a beryllium copper alloy, a copper-silver alloy, and a phosphor bronze alloy.
Further, it is preferable to have a conductive plating layer 52 of a noble metal or a noble metal alloy made of gold, silver, copper or an alloy thereof on the surface of the conductor portion 51. Thereby, the conductivity can be enhanced, and the conductivity can be adjusted by changing the type and the thickness of these plating layers 52. The plating layer 52 is excellent in solderability, and its workability can be improved.

An undercoat may be provided between the plating layer 52 and the conductor portion 51. For example, the plating layer 52
When is used as a copper plating layer, it is preferable to provide a thin nickel plating layer as a base film for the copper plating layer.
Further, it is preferable to have an insulating layer 53 on the outer periphery of the plating layer 52. The insulating layer 53 can be made of at least one or two or more resins selected from a polyurethane resin, a polyester resin, a polyesterimide resin, and a polyamide-imide resin.
It is particularly preferable to use a solderable urethane resin for the insulating layer 53. The thickness of the insulating layer 53 is not particularly limited, but is preferably in the range of, for example, 3 μm or more and 10 μm or less. Further, a nylon layer or a fusion layer may be provided on the outer periphery of the insulating layer 53.

The strand 50a preferably has an outer diameter of 20 μm or more and 60 μm or less including the plating layer 52. Tensile strength is 1400 MPa or more, conductivity is 9% IACS or more and 50%
It is preferably within the range of IACS or less.
It can be suitably used as a short suspension wire for a camera shake correction device included in an ultra-small camera module. Further, even if the diameter is small and short within the above range, the tensile strength is within the above range, so that it is preferable as a suspension wire for an image stabilization device, and even if an impact such as a drop is applied, the wire is broken or deformed. Does not occur. Further, the plating layer 5
Since the conductivity of the suspension wire including 2 is within the above range, even a small diameter wire in the above range exhibits good conductivity and can contribute to the reduction of power consumption.

As shown in FIGS. 4A and 4B, among the plurality of strands 50 of the suspension wire 18,
At least one wire 50b is made of a different material and / or shape (thickness) from the other wires 50a.
It can also be configured with.
As the wire 50b made of a different material, a non-magnetic metal wire other than copper or a wire made of a material having different elasticity such as a gel-like material or an elastomer material can be used.

For the non-magnetic metal wire, a non-magnetic stainless alloy such as austenitic stainless steel, gold, silver, lead or the like can be used.
As the gel-like material, TB3168 made of α-gel (registered trademark) manufactured by Taica Corporation or an ultraviolet curable silicone resin manufactured by ThreeBond Co., Ltd. can be used.
As the elastomer material, resin-based thermosetting elastomers such as urethane rubber, silicon rubber, and fluororubber, and thermoplastic elastomers such as polystyrene-based, polyester-based, and polyamide-based materials can be used.
By using the strands 50b having different wire diameters and materials, it is possible to correct the variation in rigidity (reaction force) existing in the plurality of strands 50 (strand wires 50a) constituting the suspension wire 18.

Further, by combining the wire 50b made of an elastic body such as a gel-like material or an elastomer material with another wire 50a, the elastic force of the entire suspension wire 18 can be adjusted.
In particular, the gel-like material can be expected to function as a vibration absorber (damper material). Specifically, the viscoelasticity of the gel-like material absorbs vibrations and stresses generated inside and vibrations from the outside, and functions so as not to affect the lens. In particular, it can be expected to play a role as anti-vibration and shock-cushioning.

The number of strands 50b composed of different materials and / or shapes (thicknesses) is preferably determined by the required rigidity (reaction force), tensile strength, and electrical resistance. Further, in the arrangement of the wire 50b having a material and / or shape (thickness) different from that of the wire 50a, the wire 50b may be arranged at a position determined by the required characteristics from the viewpoint of operation balance. preferable.
Further, when using the same material as the wire 50a and using the wire 50b having a different diameter as a different shape, the diameter may be determined by the rigidity (reaction force).
Regarding the diameter of the wire 50b made of different materials, the required rigidity (reaction force),
The size may be determined based on the tensile strength and the electrical resistance.

The length of the suspension wire 18 is not particularly limited, but a length of about 2 to 4 mm is appropriate.
The suspension wire 18 is obtained by soldering both ends of a plurality of strands 50 in advance and integrating them, and then soldering and fixing the suspension wire 18 to the first connecting portion 20 of the fixing portion 12 on one end side thereof.
It is preferable to solder and fix the movable portion 14 to the second connecting portion 22 on the other end side. In this way, by using the suspension wire 18 in which both ends of the plurality of strands 50 are integrated by soldering in advance, handling is facilitated and fixing to the first connecting portion 20 and the second connecting portion 22 is achieved. You can do it for sure.
It is not preferable to individually fix each wire 50 to the connection portion because it is troublesome in terms of work and there is a risk of disconnection.

Next, the three types of suspension wires 18 shown in FIG. 5, model A, model B, and model C.
Was prepared, and these reaction force measurements and bending tests were performed. The results are shown in FIGS. 7 and 9.

The suspension wire 18 of the model A is composed of a single wire 50 having a diameter of 49 μm, and the suspension wire 18 of the model B is φ so that the total cross-sectional area is the same as that of the model A.
The suspension wire 18 of model C consists of twisted wires (pitch 1 mm) of four strands 50 of 24 μm, and the suspension wire 18 of model C is a bundle of four strands 50 of φ34 μm so that the moment of inertia of area is the same as that of model A. It consists of (not stranded wire). Model C corresponds to the configuration of the suspension wire 18 in this embodiment. The single wire of the model A and the strands 50 of the models B and C have a circular cross section.

(Reaction force measurement)
In each model, as shown in FIG. 6, the suspension wire 18 is used with a three-point bending tester.
The reaction force was measured. When performing three-point bending with a three-point bending tester as shown in FIG. 6, the load F, the outer diameter D of the test piece X (suspension wire 18 in this measurement), Young's modulus E, and the amount of deflection Δl,
The following relationship is established between the support beams S1 and S2 and the distance L.
F = 3πD ⁴・ E ・ Δl / 4L ³
Based on this rule, the distance L between the support beams S1 and S2 of the test piece is set to 5.2 mm, and the support beams S1 and S2,
The load F was measured as a reaction force (mN) so that the amount of deflection Δl of the test piece when the load F was applied to the center point between S2 was 0.3 mm. The number of measurements n at this time was set to 5, and the average value and the maximum and minimum values of each model were obtained.
The reaction force (mN) obtained here has the same meaning as the rigidity described above because the test mode and the actuator structure are equivalent.

FIG. 7 shows the reaction force test results.
As shown in FIG. 7, in the result of reaction force measurement, there is no big difference in the average value between the models.
Suppose that in the case of a single wire of model A, the rigidity required for rigidity (reaction force) is satisfied.
As is clear from FIG. 7, the model B has a large variation in rigidity (reaction force) with respect to the model A. This may or may not occur in the cross-sectional separation in which each strand can move independently in the stranded wire of model B, and in the shape freeze in which each strand is integrated. This is because the rigidity (reaction force) fluctuates greatly.

That is, even if the aggregate of a plurality of strands 50 has the same total cross-sectional area as in model B, the rigidity (reaction force) cannot be maintained and the movable part may not be effectively supported. I understand.
On the other hand, when the suspension wire 18 is a parallel aggregate of a plurality of strands as in model C and the moment of inertia of area is set to the same level as one thick single wire of model A, the rigidity (reaction force).
In this respect, the rigidity equivalent to that of one thick single wire of model A having the required rigidity (reaction force) can be maintained in a state with little variation, and the moving parts can be sufficiently supported in terms of strength and flexibility. It turns out that it can also be maintained.

That is, when evaluating the characteristics of the suspension wire 18, it is better to use the magnitude of the moment of inertia of area as an index for selection judgment rather than considering the total cross-sectional area in terms of rigidity.

(Bending test)
Next, in each model, a bending test was performed as shown in FIG. At this time, the test speed 1
The cycle / sec, bending radius 2.5 mm, bending angle ± 90 degrees, and load 50 gf were set, and the number of bendings until the test piece of each model broke was determined. The number of measurements n at this time was set to 5, and the average value and the maximum and minimum values of each model were obtained.

FIG. 9 shows the results of the bending test.
As shown in FIG. 9, it can be seen that the number of times of bending of type B and type C is improved as compared with type A. In particular, it can be seen that the type C has more than four times the number of bendings as compared with the type A and is excellent in durability.
In type B, the number of bendings is improved by 2.5 times or more as compared with type A, but the variation is also large. This is because, as with the result of the reaction force measurement, the generated stress fluctuates due to the occurrence or non-occurrence of each strand in the stranded wire of model B in the cross-section separated state and the shape frozen state. Is.

As can be seen from FIGS. 7 and 9, the model B is constantly used due to a large variation in rigidity (reaction force) and durability as compared with the model A, and in the case of the model C, the rigidity is increased. It can be seen that in the (reaction force), the stress is relaxed while maintaining the same rigidity as the model A, and the durability (bending test) is greatly improved as compared with the model A.

Next, Table 1 is a table showing the diameter equivalent to the cross-sectional area and the diameter equivalent to the moment of inertia of area when the number of strands (single wire) having a diameter of 43 μm is increased to five one by one. It is assumed that the strands are parallel and their movements are independent.

FIG. 10 shows data obtained by actually measuring the reaction force (rigidity) when these five types of suspension wires are used.
In FIG. 10, the data indicated by the gray dots (dots) is the actual measurement data of the reaction force when the single wire is measured by changing the wire diameter.
Further, the data shown by the large black circles in FIG. 10 is the data of the reaction force corresponding to the wire at the diameter corresponding to the moment of inertia of area.
The data shown by the black triangulation points in FIG. 10 is the reaction force data when the strands correspond to the diameter equivalent to the cross-sectional area.
As is clear from FIG. 10, it is found that the reaction force increases in proportion to the diameter corresponding to the moment of inertia of area, not the diameter corresponding to the cross-sectional area, and the same result as that of FIG. 7 is obtained.

10 Lens support device 12 Fixed part 14 Moving part 16 Support mechanism 18 (18a, 18b, 18c) Suspension wire 20 First connection part 22 Second connection part 50, 50a, 50b Wire 51 Conductor part 52 Plating layer 53 Coating layer

Claims (7)

Fixed part and
A movable portion having a lens and being movably supported by a support mechanism in a direction perpendicular to the optical axis direction of the lens with respect to the fixed portion.
Equipped with
The support mechanism is
Suspension wire in which multiple elastic wires are assembled in parallel,
A first connection portion in the fixing portion to which one end of the suspension wire is connected,
It has a second connecting portion in the movable portion to which the other end of the suspension wire is connected.
A lens support device characterized in that the plurality of strands of the suspension wire are fixed to each other only by the first connecting portion and the second connecting portion. The lens support device according to claim 1, wherein the suspension wire is an assembly of two or more and seven or less strands. The lens support according to claim 1, wherein the suspension wire is located on the outer periphery and is arranged so that a straight line connecting the center points of the cross sections of adjacent strands forms a substantially regular polygon. Device. The lens support according to any one of claims 1 to 3, wherein at least one of the plurality of strands is a strand having a material and / or shape different from that of the other strands. Device. In the first connection portion and the second connection portion
The lens support device according to any one of claims 1 to 4, wherein the ends of the plurality of strands are integrated and fixed. The lens support device according to any one of claims 1 to 5, wherein a plating layer of a noble metal or a noble metal alloy is formed on each surface of the plurality of strands. The lens support device according to any one of claims 1 to 6, wherein the movable portion and the fixed portion are connected at a plurality of places by the suspension wire.

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