JP2014062976A - Camera module drive mechanism and leaf spring for the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To move a holder holding a lens unit stably with respect to a housing.SOLUTION: A camera module drive mechanism 1 includes; a housing 2A, a holder 9 which is movably located in the housing 2 and accommodates a lens unit 26A, a coil 8 mounted on the holder 9, a yoke 6 and a magnet piece 7 mounted on the housing 2A, and a pair of leaf springs 5, 11 located between the housing 2A and the holder 9. A spring constant kof one of the pair of leaf springs 5, 11 and a spring constant kof the other of the pair of leaf springs 5, 11 satisfy conditions expressed as: k≥k, (k-k)/k≤0.1.

Description

  The present invention relates to a camera module drive mechanism and a camera module drive mechanism leaf spring, and more particularly to a camera module drive mechanism and a camera module drive mechanism that can be used in a small electronic device with a camera such as a camera-equipped mobile phone. It relates to a leaf spring.

  In a camera-equipped mobile phone or the like, the lens unit can be displaced in the direction of the optical axis by the interaction between the current flowing through the coil and the magnetic field of the magnetic circuit composed of the yoke and magnet for the purpose of autofocus and zooming. A known camera module drive mechanism (voice coil motor) is known.

  In such a camera module drive mechanism, a leaf spring is used for supporting the holder holding the lens unit in the housing so as to be displaceable in the optical axis direction.

  By the way, a leaf | plate spring consists of a pair of leaf | plate spring, and each leaf | plate spring is attached to the holder and housing | casing which hold | maintain a lens unit. Of these, the upper leaf spring is attached to the upper portion of the holder, and the lower leaf spring is attached to the lower portion of the holder. The holder is supported by the upper leaf spring and the lower leaf spring.

  By the way, the upper leaf spring and the lower leaf spring have their own spring constants. In this case, if the spring constants of the upper plate spring and the lower plate spring vary, when the lens unit is displaced, the lens unit tilts due to the stress concentrated on the weaker portions of the upper plate spring and the lower plate spring. Or the lens unit cannot be displaced smoothly.

  If the lens unit is tilted or cannot be smoothly displaced in this way, it may be possible that the lens unit will come into contact with one another, or the optical axis of the lens unit may be shifted and the lens unit may not be focused.

JP2009-122360A

  The present invention has been made in consideration of the above points, and the camera module driving mechanism and the camera module driving mechanism that can smoothly displace the lens unit without tilting the lens unit during use. An object of the present invention is to provide a plate spring.

The present invention includes a housing, a lens unit that constitutes an optical system, a holder that is disposed in the housing, is capable of storing and holding the lens unit, and is movable in the optical axis direction of the lens unit, and a coil provided in the holder. A pair of leaf springs provided in the housing and provided with a yoke and a magnet piece for providing a magnetic field to the coil, and a pair of leaf springs disposed between the housing and the holder and arranged vertically. When the spring constants are k ₁ and k ₂ respectively,
k ₁ ≧ k ₂ ,
(K ₁ −k ₂ ) / k ₁ ≦ 0.1
This is a camera module drive mechanism.

  The present invention is the camera module drive mechanism in which the pair of leaf springs includes an upper leaf spring attached to the upper portion of the holder and a lower leaf spring attached to the lower portion of the holder.

  According to the present invention, each leaf spring has an outer frame part on the housing side, an inner frame part on the holder side, and a belt-like spring part between the inner frame part and the outer frame part. Mechanism.

The present invention relates to a leaf spring for a drive mechanism of a camera module having a housing and a holder for housing a lens unit, wherein the leaf spring for the drive mechanism of the camera module is composed of a pair of leaf springs, and the spring constant of the pair of leaf springs Are k ₁ and k ₂ respectively.
k ₁ ≧ k ₂ ,
(K ₁ −k ₂ ) / k ₁ ≦ 0.1
This is a leaf spring for a drive mechanism of a camera module.

  According to the present invention, the pair of leaf springs includes an upper leaf spring attached to the upper portion of the holder and a lower leaf spring attached to the lower portion of the holder. It is.

  According to the present invention, each leaf spring has an outer frame part on the housing side, an inner frame part on the holder side, and a belt-like spring part between the inner frame part and the outer frame part. It is a leaf | plate spring for mechanisms.

According to the present invention, when the spring constants of the pair of leaf springs are k ₁ and k ₂ , respectively, k ₁ ≧ k ₂ and (k ₁ −k ₂ ) / k ₁ ≦ 0.1. For this reason, there is no variation in the spring constant of the pair of leaf springs, and when the lens unit stored and held in the holder is displaced, the lens unit is not tilted, and the lens unit can be smoothly displaced. it can. For this reason, the lens unit does not come into contact with each other, and the optical axis of the lens unit is not shifted and the focus is not adjusted.

FIG. 1 is an exploded perspective view showing a drive mechanism of a camera module. FIG. 2 is a plan view showing an upper leaf spring incorporated in a camera module drive mechanism. FIG. 3 is a plan view showing a lower leaf spring incorporated in the drive mechanism of the camera module. FIG. 4 is a schematic side view showing the camera module.

  Embodiments of the present invention will be described below with reference to the drawings.

  As shown in FIGS. 1 to 4, the camera module drive mechanism 1 according to the present invention includes a housing 2A composed of a cover 2 and a base 13, a lens unit 26A composed of a plurality of lenses 26 constituting an optical system, A holder 9 which is disposed in the housing 2A and accommodates and holds the lens unit 26A and can move in the optical axis direction of the lens unit 26A, a coil 8 provided on the outer periphery of the holder 9, and a base 13 of the housing 2A. A yoke 6 and a magnet piece 7 for providing a magnetic field to the coil 8 are provided.

  A pair of leaf springs 5 and 11 are interposed between the housing 2A and the holder 9, and the pair of leaf springs 5 and 11 are arranged in the vertical direction.

  Of these, the upper leaf spring 5 is provided between the cover 2 of the housing 2A and the upper portion of the yoke 6, and the lower leaf spring 11 is provided between the base 13 of the housing 2A and the lower portion of the yoke 6. ing. In this case, an adjustment plate 4 for adjusting the thickness of the upper leaf spring 5 is provided between the upper leaf spring 5 and the cover 2.

  Then, when an electric current is passed through the coil 8 via the lower leaf spring 11, an upward force acts on the holder 9, and the lens unit 26A moves upward as a whole against the forces of the upper leaf spring 5 and the lower leaf spring 11. Can be lifted (see FIG. 4).

  Also, by adjusting the amount of current to be input, the force that moves the holder 9 upward is changed, and the balance between the force of the upper leaf spring 5 and the lower leaf spring 11 allows the holder 9 to move up and down. Position adjustment can be performed.

  As shown in FIG. 4, the housing 2 </ b> A is fixed above the base 20 via an intermediate support 21, an infrared cut glass 22 is supported on the intermediate support 21, and an image sensor 25 is provided on the base 20. Is arranged.

  Thus, the camera module 1 </ b> A is configured by the camera module drive mechanism 1 having the housing 2 </ b> A, the intermediate support 21 that supports the infrared cut glass 22, and the base body 20 on which the image sensor 25 is disposed.

  In the above configuration, as shown in FIG. 2, the upper leaf spring 5 includes an outer frame portion 5a on the housing 2A side, an inner frame portion 5b on the holder 9 side, an outer frame portion 5a, and an inner frame portion 5b. And a spring portion 5c having a spring property provided between them. Further, as shown in FIG. 3, the lower leaf spring 11 is provided between the outer frame portion 11a on the housing 2A side, the inner frame portion 11b on the holder 9 side, and between the outer frame portion 11a and the inner frame portion 11b. And a spring portion 5c having a spring property.

  Next, each component of the camera module drive mechanism 1 will be further described.

  As described above, in the space in the housing 2A composed of the cover 2 and the base 13, the holder 9 that houses and holds the lens unit 26A is housed so as to be displaceable in the optical axis direction of the lens unit 26A.

  An inner frame portion 5b of the upper leaf spring 5 and an inner frame portion 11b of the lower leaf spring 11 are respectively attached to the upper portion and the lower portion of the holder 9, and the outer frame portion 5a of the upper leaf spring 5 (see FIG. 2). ) Is attached to the upper surface of the yoke 6 fixed to the base 13 of the housing 2A, and the outer frame portion 11a (see FIG. 3) of the lower leaf spring 11 is attached to the base 13 of the housing 2A.

  A plurality of magnet pieces 7 are bonded to the yoke 6 to constitute a magnetic circuit of the actuator mechanism 1. A coil 8 is disposed in the magnetic field formed by this magnetic circuit. The coil 8 is wound around the outer periphery of the holder 9, and the holder 9 can be displaced in the optical axis direction of the lens unit 26 </ b> A by supplying a current to the coil 8. In FIG. 5, a member indicated by reference numeral 12 is a conductor (flexible printed circuit board or the like) for supplying a current from an external power source to the coil 8, and a member indicated by reference numeral 4 is the upper surface of the upper leaf spring 5 as described above. The adjustment plate is attached to the upper plate spring 5 and adjusts the thickness of the upper leaf spring 5.

  Next, the upper leaf spring 5 and the lower leaf spring 11 will be further described with reference to FIGS.

  As shown in FIG. 2, the upper leaf spring 5 includes a rectangular outer frame portion 5a, a ring-shaped inner frame portion 5b on the holder 9 side, and a spring provided between the outer frame portion 5a and the inner frame portion 5b. And a spring portion 5c.

  A first positioning hole 5A that functions as a positioning hole for attaching the upper leaf spring 5 to the upper surface of the yoke 6 fixed to the base 13 of the housing 2A is provided between the outer frame portion 5a and the spring portion 5c. It has been.

  The first positioning holes 5A are provided at the four corners of the outer frame portion 5a and in the vicinity of the connecting portion with the spring portion 5c. The first positioning hole 5A engages with a positioning protrusion (not shown) provided on the upper surface side of the yoke 6 fixed to the base 13 of the housing 2A, and the upper leaf spring 5 is engaged with the base 13 of the housing 2A. Is positioned accurately on the upper surface side of the yoke 6 fixed to the head. Further, an adhesive region 30 for adhering the upper leaf spring 5 on the first positioning hole 5A to the upper surface of the yoke 6 fixed to the base 13 of the housing 2A via an adhesive (not shown) is provided in the first positioning hole 5A. Overlaid with.

  In addition, a second positioning hole 5 </ b> B that functions as a positioning hole when the upper plate spring 5 is attached to the holder 9 is provided between the inner frame portion 5 b and the spring portion 5 c of the upper plate spring 5.

  This 2nd positioning hole 5B is provided in the connection part 17 vicinity with the spring part 5c among the ring-shaped inner frame parts 5b (refer FIG. 2). The second positioning hole 5B engages with a positioning protrusion (not shown) provided on the holder 9 side to accurately position the upper leaf spring 5 on the holder 9 side. An adhesive region 30 for adhering the upper leaf spring 5 to the holder 9 via an adhesive (not shown) is formed on the second positioning hole 5B so as to overlap the second positioning hole 5B.

  Next, the lower leaf spring 11 will be described with reference to FIG.

  As shown in FIG. 3, the lower leaf spring 11 has a rectangular outer frame portion 11a on the housing 2A side, a ring-shaped inner frame portion 11b on the holder 9 side, and an outer frame portion 11a and an inner frame portion 11b. And a spring portion 11c having a spring property.

  A first positioning hole 11A that functions as a positioning hole for attaching the lower leaf spring 11 to the base 13 of the housing 2A is provided between the outer frame portion 11a and the spring portion 11c.

  The first positioning holes 11A are provided at the four corners of the outer frame portion 11a and in the vicinity of the connecting portion with the spring portion 11c. The first positioning hole 11A engages with a positioning protrusion (not shown) provided on the base 13 side of the housing 2A to accurately position the lower leaf spring 11 on the housing 2A side. In addition, an adhesive region 30 for adhering the lower leaf spring 11 to the base 13 of the housing 2A via an adhesive (not shown) is formed on the first positioning hole 11A so as to overlap the first positioning hole 11A.

  A second positioning hole 11 </ b> B that functions as a positioning hole when the lower plate spring 11 is attached to the holder 9 is provided in the vicinity of the connecting portion 17 between the inner frame portion 11 b and the spring portion 11 c of the lower plate spring 11. .

  The second positioning hole 11B engages with a positioning protrusion (not shown) provided on the holder 9 side to accurately position the lower leaf spring 11 on the holder 9 side. An adhesive region 30 for bonding the lower leaf spring 11 to the holder 9 via an adhesive (not shown) is formed on the second positioning hole 11B so as to overlap with the second positioning hole 11B.

  Thus, the spring constant of the spring part 11c can be stabilized by accurately positioning and fixing the both end parts of the spring part 11c of the lower leaf spring 11 to the housing 2A and the holder 9, respectively.

  In FIG. 3, the outer frame 11a of the lower leaf spring 11 is provided with a connection terminal 11e connected to an external power source, and the inner frame 11b is provided with a connection terminal 11d connected to the coil 8 side. A current can flow from the power source to the coil 8 side via the lower leaf spring 11.

By the way, as shown in FIG. 3, the outer frame part 11a consists of a pair of outer frame members 11a ₁ and 11a ₂ which are separated from each other, so that the connection terminals 11e and 11e are not short-circuited. The inner frame portion 11b is composed of a pair of inner frame members 11b ₁ and 11b ₂ that are spaced apart from each other, so that the connection terminals 11d and 11d are not short-circuited.

  Next, materials for the upper leaf spring 5 and the lower leaf spring 11 will be described. Both the upper leaf spring 5 and the lower leaf spring 11 are produced by etching or punching a metal plate made of a copper alloy (beryllium copper, nickel tin copper, titanium copper, or other copper alloy). When using it as a part of conductor which sends the electric current from an external power supply to the coil 8, a material with good electrical conductivity is preferable. From the viewpoint of spring characteristics, hardness or tensile strength may be emphasized. When not used as part of a conductor for supplying current from an external power source to the coil 8, stainless steel alloys (SUS304, SUS316, TS- The upper leaf spring 5 and the lower leaf spring 11 may be made from a hard metal plate such as 4).

  Next, the spring constants of the upper leaf spring 5 and the lower leaf spring 11 will be described.

Of the upper plate spring 5 and the lower plate spring 11, whereas, for example, the spring constant of the upper leaf spring 5 and k _1, on the other hand, for example, when the spring constant of the lower leaf spring 11 and the k _2,
k ₁ ≧ k ₂
(K ₁ −k ₂ ) / k ₁ ≦ 0.1.
Here, k ₁ and k ₂ are positive (0 or more).

That is, for example, as described above, the spring constant of the upper leaf spring 5 is larger than the spring constant of the lower leaf spring 11, and the difference between the two spring constants is the spring constant of the upper leaf spring 5 (the larger one). Spring constant) k ₁ or less.

  For this reason, the spring constants of the upper leaf spring 5 and the lower leaf spring 11 do not vary. Accordingly, when the lens unit 26A housed and held in the holder 9 is displaced in the housing 2A, the lens unit 26A is not tilted, and the lens unit 26A can be smoothly displaced with good balance. For this reason, the lens unit 26A does not come into contact with each other, or the optical axis of the lens unit 26A is shifted and the lens unit 26A is not focused.

In the above-described embodiment, the example in which the spring constant of the upper leaf spring 5 is k ₁ and the constant of the lower leaf spring 11 is k ₂ has been shown. However, the spring constant of the upper leaf spring 5 is k ₂ , the spring constant of the lower leaf spring 11 may be k _1.

Also in this case, the relationship between k ₁ and k ₂ is as follows.

k ₁ ≧ k ₂
(K ₁ −k ₂ ) / k ₁ ≦ 0.1
Here, k ₁ and k ₂ are positive (0 or more).

  Next, the operation of the present embodiment having such a configuration will be described.

  First, a current is passed through the coil 8 through the lower leaf spring 11. As a result, an upward force acts on the holder 9, and the lens unit 26A can be lifted upward as a whole against the forces of the upper leaf spring 5 and the lower leaf spring 11 (see FIG. 4).

  Further, by adjusting the amount of current flowing through the coil 8, the force that moves the holder 9 upward is changed, and the balance between the force of the upper leaf spring 5 and the lower leaf spring 11 is made, so that the holder 9 moves up and down. And its position can be adjusted.

  In this case, the first positioning holes 5A and 11A are provided in the vicinity of the connecting portion of the outer plate portions 5a and 11a of the upper plate spring 5 and the lower plate spring 11 with the spring portions 5c and 11c, and the inner frame portions 5b and 11b. Second positioning holes 5B and 11B are provided in the vicinity of the connecting part 17 with the spring parts 5c and 11c, and further, an adhesive region 30 is provided on the first positioning holes 5A and 11A and the second positioning holes 5B and 11B. As a result, both ends of the spring portions 5c and 11c having the spring properties of the upper leaf spring 5 and the lower leaf spring 11 are accurately attached to the yoke 6, the base 13 and the holder 9 fixed to the base 13 of the housing 2A. Positioning can be performed well, and both end portions of the spring portions 5c and 11c can be firmly fixed to the yoke 6, the base 13 and the holder 9 fixed to the base 13 of the housing 2A.

  In this way, both ends of the spring portions 5c, 11c of the upper leaf spring 5 and the lower leaf spring 11 are accurately positioned on the yoke 6, the base 13 and the holder 9 fixed to the base 13 of the housing 2A, and By fixing firmly, the spring constant of the spring parts 5c and 11c can be stabilized.

  Thus, a camera module drive mechanism having stable spring characteristics can be obtained.

  Specifically, when a current is passed through the coil 8 via the lower leaf spring 11, an interaction occurs between the current and the magnetic field of the magnet 7, and the holder 9 moves up and down. At this time, the upper leaf spring 5 and the lower leaf spring 11 suppress the movement of the holder 9 according to the spring constant k.

  In this case, three elements (i) (ii) (iii) consisting of (i) a current flowing through the coil 8, (ii) a magnetic force of the magnet 7, and (iii) a spring constant of the upper leaf spring 5 and the lower leaf spring 11 ), The focus of the lens unit 26A can be adjusted by moving the holder 9 up and down and adjusting its position.

  Therefore, in order to perform the adjustment with the lens unit 26A with high accuracy, it is required to determine the above three elements (i), (ii), and (iii), particularly the element (iii) with high accuracy and to design stably. Yes.

  According to the present invention, among the above three elements (i), (ii), and (iii), by stabilizing the spring constant of the spring portions 5c and 11c as described above, in particular, (iii) the upper leaf spring 5 In addition, the spring constant of the lower leaf spring 11 can be stabilized. Accordingly, the vertical movement of the holder 9 and the position adjustment thereof can be performed with high accuracy, and the focal point by the lens unit 26A can be adjusted with high accuracy.

  Therefore, in use, even if an external force is applied to the upper leaf spring 5 and the lower leaf spring 11, stress concentration does not occur in the curved portion 32 of the spring portion 5 c of the upper leaf spring 5 and the spring portion 11 c of the lower leaf spring 11. . Therefore, the life of the upper leaf spring 5 and the lower leaf spring 11 can be extended, and the spring characteristics of the upper leaf spring 5 and the lower leaf spring 11 can be stabilized.

  Further, since the difference in spring constant between the upper leaf spring 5 and the lower leaf spring 11 is 1/10 or less of the larger spring constant, the spring constant between the upper leaf spring 5 and the lower leaf spring 11 varies. There is nothing. Accordingly, when the lens unit 26A housed and held in the holder 9 is displaced in the housing 2A, the lens unit 26A is not tilted, and the lens unit 26A can be smoothly displaced with good balance. For this reason, the lens unit 26A does not come into contact with each other, or the optical axis of the lens unit 26A is shifted and the lens unit 26A is not focused. In this way, the optical axis of the lens unit 26A does not shift, so that the image does not blur or blur when the camera takes an image.

  Furthermore, when the lens unit 26A is displaced, an unreasonable load is not applied, and long-term reliability of the displacement of the lens unit 26A is maintained.

DESCRIPTION OF SYMBOLS 1 Camera module drive mechanism 1A Camera module 2 Cover 2A Housing | casing 4 Adjustment board 5 Upper leaf | plate spring 5a Outer frame part 5b Inner frame part 5c Spring part 5A 1st positioning hole 5B 2nd positioning hole 6 Yoke 7 Magnet piece 8 Coil 9 Holder 11 Lower leaf spring 11a Outer frame portion 11b Inner frame portion 11c Spring portion 11A First positioning hole 11B Second positioning hole 12 Conductor (flexible printed circuit board, etc.)
13 Base 17 Connecting part 18 Wide part 20 Base 21 Intermediate support 22 Infrared cut glass 25 Imaging element 26 Lens 26A Lens unit 30 Adhesion area 32 Curved part 33 Straight line part

Claims (6)

A housing,
A lens unit constituting an optical system;
A holder that is disposed within the housing and that can store and hold the lens unit and is movable in the optical axis direction of the lens unit;
A coil provided in the holder;
A yoke and a magnet piece provided in the housing and providing a magnetic field to the coil;
A pair of leaf springs disposed between the housing and the holder and arranged in the vertical direction;
When the spring constants of the pair of leaf springs are k ₁ and k ₂ respectively,
k ₁ ≧ k ₂ ,
(K ₁ −k ₂ ) / k ₁ ≦ 0.1
The drive mechanism of the camera module characterized by the above.   2. The camera module drive mechanism according to claim 1, wherein the pair of leaf springs includes an upper leaf spring attached to an upper portion of the holder and a lower leaf spring attached to a lower portion of the holder.   3. The camera according to claim 1, wherein each leaf spring includes a housing-side outer frame portion, a holder-side inner frame portion, and a belt-like spring portion between the inner frame portion and the outer frame portion. Module drive mechanism. In a leaf spring for a drive mechanism of a camera module having a housing and a holder for storing a lens unit,
The leaf spring for the drive mechanism of the camera module consists of a pair of leaf springs,
When the spring constants of the pair of leaf springs are k ₁ and k ₂ respectively,
k ₁ ≧ k ₂ ,
(K ₁ −k ₂ ) / k ₁ ≦ 0.1
A leaf spring for a drive mechanism of a camera module.   The pair of leaf springs is composed of an upper leaf spring attached to the upper portion of the holder and a lower leaf spring attached to the lower portion of the holder.   Each leaf spring has an outer frame portion on the housing side, an inner frame portion on the holder side, and a belt-like spring portion between the inner frame portion and the outer frame portion. .

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