JP4958462B2 - Lens drive device - Google Patents

Description

  The present invention relates to a lens driving device that drives a lens support holding a lens.

  In Patent Documents 1 and 2, an electromagnetic force generated on a magnet and a yoke fixed to a housing by supporting the lens support with respect to the housing with a spring and supplying power to a coil body provided on the lens support. The lens support is driven to hold the lens support in a predetermined position by balancing the electromagnetic force and the biasing force of the spring.

JP 2005-128405 A JP 2006-58662 A

  However, since the lens driving devices disclosed in Patent Documents 1 and 2 are configured to hold the lens support in a predetermined position by balancing the biasing force of the spring and the electromagnetic force, the inertial force when the lens support is driven. When a spring is received, the spring is greatly deformed and repeatedly vibrates by being deformed in the opposite direction by a reaction force due to the elasticity of the spring, and it takes a predetermined time for the vibration of the lens support to converge. (See FIG. 11B).

  Also, since the lens support is only supported by the spring with respect to the housing, the spring is deformed more than necessary by sudden movement of the lens support when an impact is applied from the outside due to dropping or the like. As a result, the spring is damaged.

  Therefore, an object of the present invention is to provide a lens driving device that can shorten the convergence time of vibration of the lens support when the movement of the lens support stops, and can prevent the spring from being damaged by an external impact.

According to the first aspect of the present invention, an annular lens support that holds a lens, a coil body, a magnet, a yoke, and a spring are provided in the housing, and the housing is provided on the light receiving side of the lens. It is composed of a frame, a holder provided on the imaging side of the lens, and a base provided between the frame and the holder, and a yoke is closely fixed to the base, and the holder is attached to a substrate on which the light receiving element is fixed. The yoke is annularly provided on the inner periphery of the base and has a U-shaped cross section, the magnet is disposed in the U-shape of the yoke, and the coil body is disposed on the outer periphery of the lens support. It is fixed and is placed in the U-shape of the yoke so as to face the magnet, and a spring is provided between the housing and the lens support so that the lens support can be moved in the optical axis direction relative to the housing Supports the power supply to the coil body. In the lens driving device that drives the lens support in the optical axis direction of the lens by the generated electromagnetic force and holds the lens support in a predetermined position by the balance between the electromagnetic force and the biasing force of the spring, each of the frame and the holder includes the lens and face-to-face position, an opening is formed in the elastically deformable annular airtight material provided between the busy Gutotomoni lens support base an opening of the holder with a transparent image-side closure member of the annular airtight material The lens support is in close contact with the entire periphery of the periphery, and the entire periphery of the outer peripheral edge of the annular airtight material is intimately clamped between the yoke and the base, and the holder, the imaging side closing member, the base , and the lens support The imaging-side damper space is formed in a space surrounded by the lens and the annular airtight material .

  The closing member may be a hard body such as glass or hard resin, or may be a soft material such as vinyl resin.

According to a second aspect of the present invention, in the first aspect of the present invention, the annular airtight member is formed with a hole for adjusting the air pressure in the imaging side damper space.

According to the first aspect of the present invention, when the coil of the coil body is supplied with power, the lens support moves instantaneously to the light receiving side or the imaging side, but when the lens moves instantaneously, the air pressure in the imaging side damper space increases. Alternatively, the pressure is reduced to act to suppress the movement of the lens support. In this way, by forming the imaging side damper space, the air pressure in the imaging side damper space acts so as to suppress the movement of the lens support, and thus the vibration of the lens support is reduced. That is, when the lens support moves and then stops, the imaging side damper space suppresses the movement due to the inertial force acting on the lens support, and the vibration caused by the reaction force of the spring generated when the lens support moves. Converge in a short time.

  On the other hand, when an impact force is applied to the lens support due to dropping or the like, when the lens support is about to move suddenly, the imaging-side damper space suppresses excessive movement of the lens support by its air pressure. Therefore, excessive deformation of the spring is suppressed and damage to the spring is prevented.

  Since only a transparent closing member is provided at the opening of the holder, the configuration is simple.

  By providing a closing member on the holder, the closing member can also serve as a protective filter for the light receiving element.

In the imaging-side damper space , the annular airtight material vibrates as it deforms and returns in response to changes in air pressure, but the vibration of the annular airtight material has a frequency different from that of the spring, and the vibration of the spring is reduced. Can be suppressed. Further, the impact force can be mitigated by the deformation of the imaging-side damper space against an impact when dropped.

  Further, the volume of the imaging side damper space can be reduced, and a stronger damper action can be obtained.

According to the second aspect of the present invention, the same effect as that of the first aspect of the present invention can be obtained, and the lens support can be obtained by adjusting the pressure in the imaging-side damper space due to the movement of the lens. The movement of the lens support can be smoothly performed without the damper space hindering the movement of the body (normal movement).

  Embodiments of the present invention will be described below with reference to the accompanying drawings. First, the first embodiment of the present invention will be described with reference to FIGS. 1 to 3 and 11. FIG. 1 is a longitudinal sectional view of the lens driving device according to the first embodiment, FIG. 2 is an exploded perspective view of the lens driving device according to the first embodiment, and FIG. 3 is according to the first embodiment. FIG. 11 is a perspective view showing a part of the lens driving device in a cut state. FIG. 11 shows the lens driving device according to the present embodiment, in which the vibration of the lens support when the lens support moves is measured every elapsed time. It is a graph. 2 and 3, the lens and the holder are omitted, and in FIG. 3, the light receiving side closing member is further omitted.

  The lens driving device 1 according to the first embodiment is a lens driving device for an autofocus small camera incorporated in a mobile phone (camera device).

  The lens driving device 1 includes a housing 2, and a lens support 5 that holds the lens 3, a coil body 7, a magnet 9, a yoke 11, a light receiving side spring 13 a, and an image formation in the housing 2. A side spring 13b is provided.

  The housing 2 includes a frame 15 provided on the light receiving side, a holder 17 provided on the imaging side, and a base 19 provided between the frame 15 and the holder 17.

  The base 19 has an annular yoke 11 in close contact with the inner periphery thereof. The yoke 11 has a U-shaped cross section, and a magnet 9 is arranged in the circumferential direction in the U-shape of the yoke 11. An annular coil body 7 arranged facing the magnet 9 in the U-shape of the yoke is provided. The lens 3 is provided so as to be movable in the optical axis direction.

  The coil body 7 is fixed to the outer periphery of the lens support 5 and moves together with the lens support 5.

  The lens support 7 has a substantially cylindrical shape and is disposed on the inner peripheral side of the yoke 3. The lens 3 is held on the inner peripheral side of the lens support 7.

  A light receiving side spring 13a is attached to the light receiving side end of the lens support 7, and an image forming side spring 13b is attached to the image forming side end. When the lens support 7 moves, the spring 13a, 13b is elastically deformed.

  The light receiving side spring 13a and the image forming side spring 13b are annular leaf springs (see FIG. 2). The inner peripheral side end of the light receiving side spring 13a is fixed to the lens support 7, and the outer peripheral side end is a yoke. 11 and the frame 15 are sandwiched and fixed. The inner peripheral side end of the image forming side spring 13b is fixed to the lens support 7, and the outer peripheral side end is fixed to the base 19 by being pressed by the spacer 21 from the frame 15 side. The spacer 21 insulates the image forming side spring 13b from the yoke 11.

  The frame 15 has a rectangular shape in plan view (see FIGS. 2 and 3), and a light receiving hole 23 is formed at the center. In the present embodiment, the light receiving hole 23 is closed by fitting the light receiving side closing member 25 into the light receiving hole 23. The frame 15 is fitted and fixed to the base 19 and closely contacts the light receiving side corner portion 11a of the yoke 11 in the circumferential direction. The light receiving side closing member 25 is made of a transparent material, and is provided to face the light receiving surface 3 a of the lens 3.

  As shown in FIG. 1, a light receiving side damper space 39 hermetically sealed by the lens 3, the yoke 11, the frame 15, and the light receiving side closing member 25 is formed.

  The holder 17 is tightly fixed to the base 19. The holder 17 is attached to a substrate 29, and an image sensor (CCD) is provided as the light receiving element 31 on the substrate 29, and the holder 17 covers the light receiving element 31. An opening 33 is formed in the central portion of the holder 17, and the opening 33 of the holder is closed with a transparent ligation side closing member 35. The image-side closing member 35 is provided to face the imaging side surface of the lens 3.

  As shown in FIG. 1, the image forming side damper space 43 is formed by the holder 17, the image forming side closing member 35, the base 19, the yoke 11, the lens support 5 and the lens 3.

  The clearance S (see FIG. 1) between the outer peripheral surface of the lens support 5 and the inner peripheral surface of the yoke is set to be extremely small (for example, about 70% or less of the conventional one), and the light receiving side damper space 39 or The damper action of the imaging side damper space 43 is not affected.

  Next, functions and effects of the lens driving device 1 according to the present embodiment will be described. When power is supplied to the coil body 7 during driving, an electromagnetic force is generated in the coil body 7 in the magnetic field of the magnet 9 and the lens support 5 moves in the optical axis direction. The lens support 5 stops when the driving force of the lens support 5 and the urging forces of the light receiving side spring 13a and the imaging side spring 13b are balanced.

  When the lens support 5 is instantaneously moved to the light receiving side after the lens support 5 is moved and stopped, the air pressure in the light receiving side damper space 39 is increased and the air pressure in the imaging side damper space 43 is reduced. An attempt is made to suppress vibration at the stop position of the lens support 5. As a result, when the lens support 5 stops moving, further movement due to the inertial force is suppressed. After the lens support 5 moves due to the inertial force, it is received when the lens support 5 moves to the image forming side due to the reaction force of the springs 13a and 13b. The air pressure in the side damper space 39 is reduced, and the air pressure in the imaging side damper space 43 is increased to suppress the movement of the lens support 5.

Thus, in the present embodiment, when the lens support 5 is stopped by suppressing the movement due to the inertial force acting on the lens support 5 in both the light receiving side damper space 39 and the imaging side damper space 43. The vibrations of the springs 13a and 13b generated in the above can be converged in a short time.

  On the other hand, when an impact force is applied to the lens support 5 due to dropping or the like, when the lens support 5 is about to move suddenly, the light-receiving side damper space 39 and the imaging side damper space 43 are moved by the air pressure. Since excessive movement of the support 5 is suppressed, excessive deformation of the springs 13a and 13b is prevented, and damage to the springs 13a and 13b is prevented.

  In addition, since the closing member 25 is provided in the opening 23 of the frame 15 and the transparent closing member 35 is provided in the opening 33 of the holder 17, the configuration is simple.

  By providing the light-receiving side closing member 25 in the opening 23 of the frame 15, the closing member 25 also serves as a protective filter for the lens 3, and dust or the like can be prevented from attaching to the lens 3.

  By providing the imaging side closing member 35 in the opening 33 of the holder 17, the closing member 35 can also serve as a protective filter for protecting the light receiving element 31 from dust.

  Here, an experiment was conducted to measure the vibration convergence time when the lens support 5 in the lens driving device 1 according to the first embodiment stopped after moving, and will be described in comparison with the conventional example.

  In the experiment, the same voltage and current were applied to the coils of the example product and the comparative product, and the time until the lens support 5 was stopped was measured. The measurement was performed using a laser length measuring device, and the weight of the lens was 0.2 g. The result is shown in FIG. (A) of FIG. 11 is an example product, and (b) is a comparative example product.

  As is apparent from the results shown in FIG. 11, the lens support 5 vibrates at the stop position in any case, but in the example product (a), the time t until the vibration converges is 0.07 seconds. In contrast, the conventional product took 0.8 seconds. That is, in this experiment, the convergence time of vibration when the lens support was moved and then stopped could be about 10 times faster than before.

  Hereinafter, other embodiments of the present invention will be described with reference to FIGS. 4 to 10. In the embodiments described below, the same effects as those of the above-described first embodiment are provided. The same reference numerals are given to omit the description thereof, and in the following description, differences from the first embodiment will be mainly described.

  FIG. 4 is a longitudinal sectional view of the lens driving device 1 according to the second embodiment. In the second embodiment, in the first embodiment, the light receiving side corner portion 11a of the yoke 11 and the frame 15 are hermetically sealed with a sealing material (adhesive material) 37 over the entire circumference thereof. A sealant (adhesive) 38 is hermetically sealed between the outer peripheral surface and the base 19 over the entire circumference, and a sealant (adhesive) 41 is also provided between the base 19 and the holder 17 over the entire circumference. Airtight. In the second embodiment, since the air tightness of each of the light receiving side damper space 39 and the image forming side damper space 43 is increased, an effect superior to that of the first embodiment can be achieved. That is, the contraction time of the vibration of the lens support can be shortened compared to the first embodiment, and damage to the springs 13a and 13b when an external force is applied to the lens support 5 due to dropping or the like can be further reduced.

  FIG. 5 is a longitudinal sectional view of the lens driving device 1 according to the third embodiment. In the third embodiment, in the first embodiment described above, a closing member is provided only in the opening 33 of the holder 17, and no closing member is provided in the opening 23 of the frame, and only the imaging side damper space 43 is provided. Formed. Further, the outer periphery of the yoke 11 and the base 19 are hermetically sealed with a sealing material (adhesive) 38 over the entire circumference, and the sealing material (with the entire circumference between the base 19 and the holder 17 ( Adhesive) 41 is airtight.

  In the third embodiment, since there is no light-receiving side damper space 39, a synergistic effect with the light-receiving side damper space 39 cannot be obtained. It is possible to shorten the convergence time of vibration during the movement, and to prevent damage due to excessive deformation of the springs 13a and 13b even when an impact such as dropping is applied.

6 and 7 show a lens driving device 1 according to a fourth embodiment. FIG. 6 is a longitudinal sectional view of a lens driving device according to the fourth embodiment, and FIG. 7 is an exploded perspective view. In the fourth embodiment, in place of the imaging-side spring 13b in the third embodiment described above, an elastically deformable annular airtight material (cone member) 47 is provided, and the outer peripheral side end is used as a base. 19 is held by the yoke 11 via the spacer 21, and the annular airtight member 47 is substantially sandwiched between the base 19 and the yoke 11 .

  The annular airtight material 47 is a resin or paper face, and in the case of resin, polyethylene terephthalate (PET), polyethylene naphthalate, polyether nitrile, polyether imide, or the like can be used. The annular airtight member 47 can be elastically deformed between the outer peripheral side end and the inner peripheral side end in the same manner as the spring and holds the lens support 5 and the base 19 in an airtight manner.

  According to the fourth embodiment, the space between the lens support 5 and the base 19 is kept airtight by the annular airtight member 47, so that the airtightness of the imaging-side damper space 43 can be improved, and the third embodiment A higher damper effect can be obtained by the imaging-side damper space 43 than in the embodiment.

  FIG. 8 shows a lens driving device 1 according to the fifth embodiment. FIG. 8A is a longitudinal sectional view of a lens driving device according to a fifth embodiment, and FIG. 8B is a perspective view showing an annular airtight material extracted. In the fifth embodiment, in the fourth embodiment described above, the space between the base 19 and the holder 17 is sealed with the sealing material 41 to improve the airtightness of the imaging-side damper space 43 and the annular shape. An air pressure adjusting hole 49 is formed in the airtight member 47 to adjust the air pressure in the imaging side damper space 43.

  According to the fifth embodiment, when the lens support 5 is moved, the air pressure in the imaging-side damper space is released from the air pressure adjusting hole 49, so that the movement of the lens support 5 is prevented from being suppressed. In addition, the lens support 5 can move smoothly, and the imaging-side damper space 43 can act effectively in the case of a sudden movement due to an impact such as vibration or dropping when the lens support 5 is stopped. .

  Note that the number and size of the air pressure adjusting holes 49 are appropriately set as necessary.

  FIG. 9 shows a lens driving device 1 according to the sixth embodiment. FIG. 9 is a longitudinal sectional view of a camera apparatus according to the sixth embodiment. In the sixth embodiment, in the lens driving device 1 according to the first embodiment described above, the closing member 25 is not provided in the opening of the frame 15 and is assembled to the assembly member 51 of the camera. The assembly member 51 is provided in close contact with the light receiving side surface 15 a of the frame 15. The assembly member 51 is provided with an opening 53 on the opposite surface of the lens 3. The opening 53 is closed with a transparent light-receiving side closing member 25, and the light-receiving side closing member 25, the assembly member 51, the frame 15, and the yoke 11. A light receiving side damper space 39 is formed in a space surrounded by the lens support 5 and the lens 3.

  According to the sixth embodiment, since the two damper spaces 39 and 43 of the light receiving side damper space 39 and the imaging side damper space 43 act on the lens support 5 from both sides as in the first embodiment. The same effects as those of the first embodiment can be achieved.

  FIG. 10 shows a lens driving device 1 according to the seventh embodiment. FIG. 10 is a longitudinal sectional view of a camera apparatus according to the seventh embodiment. In the seventh embodiment, in the lens driving device 1 according to the sixth embodiment described above, an elastic member (rubber material) is provided between the frame 15 and the assembly member 51 to provide the frame 15 and the assembly member 51. Is intended to be airtight.

  According to the seventh embodiment, since the airtightness of the light receiving side damper space 39 in the sixth embodiment can be increased, the damper action of the light receiving side damper space 39 can be further increased.

  The present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the scope of the present invention.

  For example, in the fourth and fifth embodiments, the spacer 21 may not be provided. In the fourth and fifth embodiments, an image forming side spring 13b may be further provided.

  In the second embodiment, as shown in FIG. 12, an air pressure adjusting hole 61 is provided in the frame 15 and the base 19 to adjust the air pressure in the light receiving side damper space 39 and the imaging side damper space 43. Good. The air pressure adjusting hole 61 may be provided in either the frame 15 or the base 19, and is not limited to the second embodiment, but may be the first, third, and fourth embodiments, the sixth and Similarly, in the seventh embodiment, the air adjustment hole 61 may be provided. Further, in the fifth embodiment, the air adjustment hole 61 may be provided in the base 19 in place of the air pressure adjustment hole 49 provided in the annular airtight material 47 or together with the air pressure adjustment hole 49.

It is a longitudinal cross-sectional view of the lens drive device concerning 1st Embodiment. It is a disassembled perspective view of the lens drive device concerning a 1st embodiment. It is a perspective view which cut | disconnects and shows a part of lens drive device concerning 1st Embodiment. It is a longitudinal cross-sectional view of the lens drive device concerning 2nd Embodiment. It is a longitudinal cross-sectional view of the lens drive device concerning 3rd Embodiment. It is a longitudinal cross-sectional view of the lens drive device concerning 4th Embodiment. It is a disassembled perspective view of the lens drive device concerning 4th Embodiment. (A) is a longitudinal cross-sectional view of the lens drive device concerning 5th Embodiment, (b) is a perspective view which extracts and shows an annular airtight material. It is a longitudinal cross-sectional view of the camera apparatus concerning 6th Embodiment. It is a longitudinal cross-sectional view of the camera apparatus concerning 7th Embodiment. It is the graph which measured the vibration of the lens support body for every elapsed time when the lens support body moved about the lens drive device concerning a 1st embodiment. It is a longitudinal cross-sectional view of the lens drive device concerning the modification of this invention.

DESCRIPTION OF SYMBOLS 1 Lens drive device 2 Housing | casing 3 Lens 5 Lens support body 7 Coil body 9 Magnet 11 Yoke 13a Light reception side spring 13b Image formation side spring 15 Frame 17 Holder 19 Base 25 Light reception side closing member 31 Light receiving element 35 Image formation side closing member 37 , 38, 41 Sealing material 47 Annular airtight material 51 Assembly member 55 Elastic member

Claims (2)

An annular lens support that holds the lens, a coil body, a magnet, a yoke, and a spring are provided in the housing. The housing is provided on the light receiving side of the lens and on the imaging side of the lens. And a base provided between the frame and the holder. A yoke is closely fixed to the base. The holder is attached to a substrate on which the light receiving element is fixed. It is provided in a ring shape on the inner circumference and has a U-shaped cross section, the magnet is arranged in the U-shape of the yoke, and the coil body is fixed to the outer circumference of the lens support and faces the magnet. Located in the U-shape of the yoke, the spring is provided between the case and the lens support, and supports the lens support so that it can move in the optical axis direction relative to the case. The electromagnetic force generated by the In a lens driving device that holds a lens support in a predetermined position by driving the support in the optical axis direction of the lens and balancing the electromagnetic force and the biasing force of the spring, the frame and the holder are each opened at a position facing the lens. There are formed, the elastically deformable annular airtight material provided between the busy Gutotomoni lens support base an opening of the holder with a transparent image-side closure member, the entire circumference of the inner peripheral edge of the annular airtight material The lens support is in close contact, and the entire circumference of the outer peripheral edge of the annular airtight material is tightly clamped between the yoke and the base, and the holder, the imaging side closing member, the base , the lens support, the lens, and the annular airtight A lens driving device characterized in that a closed imaging-side damper space is formed in a space surrounded by a material . 2. The lens driving device according to claim 1 , wherein a hole for adjusting an air pressure in the imaging side damper space is formed in the annular hermetic material.

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