JP3950103B2 - Camera lens drive device - Google Patents

Description

  The present invention relates to an autofocus lens driving device used for a portable small camera.

  In Patent Document 1, a lens support body of a camera is connected to a shaft of a motor via a gear, the lens support body is moved by driving the motor, and the lens support body is returned to an initial position by a biasing force of a spring. Is disclosed.

  Patent Document 2 discloses a technique for providing a spring that is pressed to accumulate pressure when the lens support moves a predetermined distance, and prevents rattling when the lens support moves due to the engagement between the cam groove and the pin. Yes.

JP 7-140523 A Japanese Patent Laid-Open No. 2003-262779

  By the way, in a lens driving device used for a portable small camera, since the small camera is often carried around in a pocket or back, the lens driving device is shaken or shocked when the small camera is carried (when not in use). Sometimes.

  When the lens support is configured to move by electromagnetic force instead of being driven by the engagement of the cam and the pin or the gear engagement, the lens support is shaken or shocked. Therefore, the lens support is susceptible to displacement and damage due to shaking and impact when the camera is not used.

  In such a case, it is conceivable to simply attach a spring to the lens support and relieve the movement of the lens support by an urging force. However, when the lens support moves due to shaking or impact, Since the urging force of the spring acts for the first time, there is a problem that it is inferior in impact resistance.

  Accordingly, an object of the present invention is to provide a lens driving device having a simple configuration and excellent impact resistance in a configuration in which a lens support is driven by electromagnetic force.

According to the first aspect of the present invention, there is provided a yoke having a cylindrical shape with a U-shaped cross section, a base on which the yoke is mounted, a magnet and a coil disposed inside the U-shape of the yoke, and an inner peripheral side of the yoke. A lens support having a coil disposed on the outer periphery, a front spring and a rear spring having an inner peripheral end attached to the lens support and an outer peripheral end attached to the yoke. A side spring is a lens driving device for a camera that is attached to the lens support before and after the optical axis direction of the lens, and moves the lens support in the optical axis direction of the lens by electromagnetic force generated by energizing the coil. Each of the front spring and the rear spring is a substantially annular leaf spring, and an annular outer peripheral end and an annular inner peripheral end are connected by a plurality of arms. Circumferential It is provided with the a position, a lens support in a state where no current to the coil to impart a biasing force towards the base, characterized in that it is pressed against the base of the lens support.

According to a second aspect of the invention, in the invention of the first aspect, each arm portion extends along the circumferential direction and includes a plurality of continuous curved portions in the longitudinal direction. .

According to a third aspect of the present invention, in the first aspect of the present invention, each arm portion is substantially S-shaped in the circumferential direction.

The invention according to claim 4 is the invention according to claim 2 or 3, wherein the connecting portion between the arm portion and the outer peripheral side end portion and the inner peripheral end portion have a radial cross section. It is curved.

  According to a fifth aspect of the present invention, in the invention according to any one of the second to fourth aspects, at least one of the front spring and the rear spring is more than the inner peripheral side end in the natural state before assembly. A step is formed between the inner peripheral end and the outer peripheral end so that the outer peripheral end is located on the front side in the optical axis direction, and the inner peripheral end and the outer periphery are assembled by attaching a spring. It is characterized in that an urging force is applied by reducing the level difference from the side end portion.

  According to the first aspect of the present invention, when the coil is not energized, that is, when the camera is not in use, the lens support is biased by the spring and pressed against the base. When the camera is shaken or shocked when it is carried, the lens support is hardly shaken or rattled and has excellent impact resistance.

In particular, since the lens support is pressed against the base by the resultant force of the urging force of the front spring and the urging force of the rear spring, a large urging force can be obtained even if the urging force of each spring is small. Since a large urging force is not required, the influence of the urging force of the spring at the time of assembly can be reduced , and the assembly can be easily and simply structured.

  In addition, the lens support is moved by electromagnetic force, and since there is no engagement with a gear or cam groove as in the conventional case, it is possible to prevent rattling due to these precision errors, and there is no gear or cam, so the size can be reduced. Can be planned.

By using substantially annular leaf springs for the front spring and the rear spring, respectively, a simple structure can be obtained and the assembly can be easily performed.

According to the second aspect of the present invention, the function and effect of the first aspect can be obtained, and the arm portion is formed with a curved portion that is continuous in the circumferential direction. Even in the case of acting, the arm portion can expand and contract in the circumferential direction to reduce the impact.

  According to the invention described in claim 3, the effects described in claim 1 can be obtained, and the arm portion is substantially S-shaped even when an impact force in the radial direction or the peripheral direction of each spring is applied. Therefore, the impact can be reduced by expanding and contracting in these directions, and the degree of freedom for reducing the impact is high.

  According to the invention described in claim 4, it is possible to obtain the operation effect described in claim 2 or 3, and further facilitate the expansion and contraction in the radial direction even when the radial impact force of each spring is applied. Can alleviate the impact. Moreover, the connection intensity | strength in the connection part of the outer peripheral side edge part and inner peripheral side edge part in an annular leaf | plate spring can be raised.

According to the invention described in claim 5 , it is possible to obtain the function and effect described in any one of claims 2 to 4, and in the natural state of the spring (a state where no load is applied to the spring), the inner peripheral side end The spring plate can be formed so that there is a step between the portion and the outer peripheral side end, and the biasing force of the spring can be increased by assembling with a small step during assembly. Therefore, the lens support can be pressed against the base with a high urging force, and the impact resistance can be further improved.

  Embodiments of the present invention will be described below with reference to the accompanying drawings. FIG. 1A is a sectional view showing a state before driving of the lens driving device according to the embodiment of the present invention, FIG. 1B is a side view showing the front spring extracted, and FIG. 3 is an exploded perspective view of the lens driving device shown in FIG. 3, FIG. 3 is a plan view of the front spring shown in FIG. 2, FIG. 4 is a sectional view taken along line BB in FIG. 3, and FIG. FIG. 6 is a sectional view showing a state where the lens driving device shown in FIG. 1 is driven.

Camera lenses driving apparatus 1 according to this embodiment, a lens driving apparatus of an autofocus camera incorporated into a mobile phone.

  The lens driving device 1 includes a substantially cylindrical yoke 3, a base 5 on which the yoke 3 is mounted, a lens support 7 disposed on the inner peripheral side of the yoke 3, and a front spring attached to the lens support 7. 9 and a rear spring 11. The front spring 9 is arranged on the front side (one side) of the lens support 7 in the optical axis direction of the lens, and the rear spring 11 is rear side in the optical axis direction of the lens (the other side). ).

  The yoke 3 has a substantially U-shaped cross section, and a magnet 13 is disposed inside the U-shape, and a coil 15 is disposed on the inner peripheral side of the magnet inside the U-shape. The magnet 13 is fixed to the base 5 via a rear spacer 17. The coil 15 is fixed to the outer peripheral portion 7 a of the lens support 7, and the outer peripheral portion 7 a of the lens support 7 enters the inside of the yoke 3, and the outer peripheral portion 7 a of the lens support 7 is the U-shaped gap of the yoke 3. Is supposed to move.

  The base 5 has an outer peripheral wall 5 a positioned along the outer peripheral surface of the yoke 3, and a base portion 5 b positioned on the rear side of the yoke 3 (the rear side in the optical axis direction of the lens). A yoke 3 is fixed on the circumferential side. Further, an outer peripheral end portion 11 b of the rear spring 11 is fixed between the base portion 5 b and the rear spacer 17.

  A sensor holder 19 is attached to the base 5 b of the base 5.

  The lens support 7 has a substantially cylindrical shape, in which a lens 20 is housed, and is attached to the inner peripheral side of the yoke 3 so as to be movable along the optical axis.

  The front spring 9 is a substantially annular leaf spring, and has an inner peripheral end 9a and an outer peripheral end 9b. The inner peripheral end 9a is sandwiched and fixed between the lens support 7 and the cap 24. The outer peripheral side end portion 9 b is sandwiched and fixed between the yoke 3 and the frame 23, and a front spacer 21 is interposed between the outer peripheral side end portion 9 b and the yoke 3.

  The rear spring 11 and the front spring 9 have substantially the same shape and are substantially annular leaf springs. The inner peripheral end 11 a of the rear spring 11 is fixed to the rear end of the lens support 7, and the outer peripheral end 9 b is fixed between the base portion 5 b of the base 5 and the rear spacer 17.

  These front side spring 9 and rear side spring 11 are flat in a natural state (unloaded state) before assembly, but after assembly, as shown in an enlarged view in FIG. The peripheral side end portions 9a and 11a are attached in a deformed state so as to be positioned in front of the outer peripheral side end portions 9b and 11b. As a result, a biasing force is always applied to the inner peripheral side end portions 9a, 11a toward the base substrate side by the restoring force (biasing force) of the spring.

  Here, the configuration of the front spring 9 and the rear spring 11 will be described in more detail with reference to FIGS. 3 to 5. However, since the configurations of the front spring 9 and the rear spring 11 are substantially the same, The configuration of the rear spring 11 will be omitted.

  The front spring 9 is provided with three arm portions 25 between the inner peripheral end portion 9a and the outer peripheral end portion 9b, and each arm portion 25 has an inner peripheral end portion 9a and an outer peripheral end portion. 9b. Each arm portion 25 extends in the circumferential direction, and an insertion space 27 for the projection 7b (see FIG. 1) of the lens support 7 is provided between the adjacent arm portions 25, 25. The protrusion 7 b of the lens support 7 can be brought into contact with the base portion 5 b of the base 5 through the insertion space 27.

  As shown in FIGS. 3 and 4, the arm portion 25 is formed with a curved portion 27 that is continuous in the circumferential direction, and can be elastically deformed in the circumferential direction. Further, as shown in FIGS. 3 (C-C cross section) and FIG. 5, a radial curved portion 29 is formed in the connecting portion 25a with the outer peripheral side end portion 9b of the arm portion 2, and the connecting portion 25a. The distortion is prevented and the strength is increased. Similarly, the EE cross section shown in FIG. 3 is the same as FIG. 5 and the cross sectional view thereof is omitted. However, the curved portion 29 in the radial direction is also provided in the connecting portion 25b with the inner peripheral side end portion 9a of the arm portion 25. It is formed, and distortion prevention and strength are enhanced.

Next, the assembly, operation, and effect of the lens driving device 1 according to the present invention will be described.
Assembling is performed by attaching the inner peripheral end 11a of the rear spring 11 to the lens support 7, placing the magnet 13 and the coil 15 fixed to the lens support 7 inside the yoke 3, and the base 5b of the base 5. Are assembled via the rear spacer 17. Incidentally, the projection 7 b of the lens support 7 is inserted into the insertion space 27 of the rear spring 11. Thereafter, the inner peripheral end 9 a of the front spring 9 is placed between the front spacer 21 and the yoke 3 and fixed with the cap 24, and the frame 23 is attached to the base 5, and the outer peripheral end 9 b is fixed with the frame 23. Fix it.

  In the assembled state, the front spring 9 and the rear spring 11 are in a state where the inner peripheral side end portions 9a and 11a protrude forward from the outer peripheral side end portions 9b and 11b, respectively (see FIG. 1 (b). )), And the protrusion 7a of the lens support 7 is in contact with the base 5b of the base 5. Accordingly, since the spring restoring force (arrow in FIG. 1B) acts on the front spring 9 and the rear spring 11 respectively, the resultant force of the urging forces of the two springs 9 and 11 is applied to the lens support 7. Therefore, the lens support 7 is hardly shaken or rattled even when shaken or impact occurs, and the impact resistance is excellent.

  In this case, since the lens support 7 is pressed against the base portion 5b of the base 5 by the resultant force of both the front spring 9 and the rear spring 11, a large urging force is obtained even if the urging forces of the springs 9 and 11 are small. In addition, since a large urging force is not required for one spring, the influence of the urging force of the spring can be reduced at the time of assembly, and the assembly can be easily and simply configured.

  Further, since the lens support 7 is moved by electromagnetic force and is not engaged with a gear or a cam groove as in the prior art, it is possible to prevent rattling due to these accuracy errors and to reduce the size. it can.

  In the front spring 9 and the rear spring 11, the curved portion 27 that is continuous in the circumferential direction is formed on the arm portion 25. Therefore, even when a circumferential impact force is applied, the arm portion 25 is expanded and contracted in the circumferential direction. Can reduce the impact.

  Further, even when a radial impact force is applied to the front spring 9 and the rear spring 11, curved portions are formed at the connecting portions 25 a and 25 b between the outer peripheral end and the inner peripheral end of the arm portion 25. Therefore, the impact can be reduced by expanding and contracting in the radial direction, and the connection strength can be increased.

  When the coil 15 is energized, as shown in FIG. 6, the lens support 7 is moved forward by a predetermined amount by electromagnetic force, and the focal length of the lens is adjusted.

  Next, another embodiment of the present invention will be described. In the embodiment described below, parts having the same operational effects as those of the above-described embodiment are denoted by the same reference numerals. Detailed description will be omitted, and different points from the above-described embodiment will be mainly described.

  FIG. 7 is a cross-sectional view illustrating a state before the frame is assembled in the second embodiment. In this embodiment, the front spring 9 is different from the above-described embodiment in that a step is provided at the inner peripheral side end portion 9a and the outer peripheral side end portion 9b in a natural state (no load). . Then, the frame 23 is attached and the outer peripheral side end portion 9b is fixed and assembled so as to reduce the level difference during assembly. In this way, by forming the front spring 9 with a step between the inner peripheral end 9a and the outer peripheral end 9b, the urging force (returning force) of the spring after assembly can be further increased, which is high. The lens support 7 can be pressed against the base portion 5b of the base 5 by the urging force, and the impact resistance can be further improved.

  FIG. 8 is a plan view of the front spring 9 and the rear spring 11 according to the third embodiment. In the third embodiment, the arm portion 25 is formed so as to be substantially S-shaped in the radial direction, and even when a swing or impact in the circumferential direction, the radial direction, or an oblique direction with respect to these acts. It can be deformed and absorbed, has a high degree of freedom for shock buffering, and has excellent impact resistance.

  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, the radial curved portion 29 formed in each connecting portion 25a of the front spring 9 and the rear spring 11 may be a concave curved portion as shown in FIG.

  Moreover, in 3rd Embodiment shown in FIG. 8, the curved part 27 is provided in the arm part 25 similarly to 1st Embodiment, or outer periphery side edge part 9b, 11b and inner periphery side edge part 9a, 11a The connecting portions 25a and 25b may be formed by bending.

(A) is a sectional view showing a state before the driving of the camera lenses driving apparatus according to an embodiment of the present invention, is a side view illustrating only (b) is front spring. It is a disassembled perspective view of the lens drive device shown in FIG. It is a top view of the front side spring shown in FIG. It is BB sectional drawing of FIG. It is CC sectional drawing of FIG. It is sectional drawing which shows the state which the lens drive device shown in FIG. 1 drive. It is sectional drawing in the assembly process of the lens drive device concerning 2nd Embodiment. It is sectional drawing in the assembly process of the lens drive device concerning 3rd Embodiment. It is sectional drawing explaining the modification by this Embodiment.

Explanation of symbols

Lenses drive for 1 camera 3 yoke 5 base 7 lens support 7b protrusion 9 front spring 9a in the inner edge portion 9b outside inner-side end portion 11 rear spring 11a peripheral end 11b outer end portion 13 the magnet 15 coil 25 Arm part 25a Connection part of outer peripheral side end part 25b Connection part of inner peripheral side end part 27 Curved part in circumferential direction 29 Curved part in radial direction

Claims (5)

A yoke having a U-shaped cylindrical shape, a base on which the yoke is mounted, a magnet and a coil disposed inside the U-shape of the yoke, and disposed on the inner peripheral side of the yoke and fixed to the outer periphery. And a front spring and a rear spring having an inner peripheral end attached to the lens support and an outer peripheral end attached to the yoke. The front spring and the rear spring are optical axes of the lens. A lens driving device for a camera that is attached to the lens support before and after the direction, and moves the lens support in the optical axis direction of the lens by electromagnetic force generated by energizing the coil,
Each of the front spring and the rear spring is a substantially annular leaf spring, in which an annular outer peripheral end and an annular inner peripheral end are connected by a plurality of arms, and each arm is in the circumferential direction. different is provided with a position, a lens support in a state where no current to the coil to impart a biasing force toward the base, camera lenses, characterized in that presses the lens support base of Drive device. Each arm portion extends along the circumferential direction and and camera lenses driving apparatus according to claim 1, characterized in that it comprises a curved portion for a plurality of consecutive in the longitudinal direction. Each arm portion, camera lenses driving apparatus according to claim 1, characterized in that has a substantially S-shape in the circumferential direction. 4. The camera lens according to claim 2, wherein a cross section in a radial direction is curved at a connection portion between the outer peripheral side end portion and an inner peripheral side end portion of the arm portion. Drive system. At least one of the front side spring and the rear side spring has an inner peripheral side end part and an outer peripheral part in a natural state before assembly so that the outer peripheral side end part is positioned on the front side in the optical axis direction rather than the inner peripheral side end part. 5. A step is formed between the side end and a biasing force is applied by reducing the step between the inner peripheral end and the outer peripheral end by assembling the spring. camera lenses driving device according to any one of.

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