JP2006337763A - Lens holding means - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a lens holding means which has an impact resistance performance against external force in a lens optical system, in which time until the impact resistance performance is given is short, and has sufficient impact resistance performance even in a photographing state. <P>SOLUTION: In the lens optical system, a lens 13 is held by a lens barrel 11 and electromagnetic force generated by a coil 12. An external acceleration is detected by an acceleration sensor 16. According to the detected signal, the magnitude of the electromagnetic force from the coil 12 is controlled. Thereby, holding force for the lens 13 is changed from strong hold to weak hold. This makes is possible to reduce external impact applied to the lens 13 and lens barrel 11 instantly. In addition, by disposing a cushioning material 18 in the lens barrel 11, the impact can be more effectively reduced. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a means for holding a lens of a lens optical system mounted on a camera or the like. In particular, the present invention relates to an improvement in a configuration that allows a lens holding state to be changed.

  Conventionally, regarding a lens optical system in a camera or the like, a form in which a lens unit is incorporated in a camera body has been adopted. Therefore, when the user drops the camera, that is, when an external impact force acts on the camera, even if the camera body has sufficient strength, it is placed inside the camera. It is conceivable that an impact force acts on the lens optical system and damages the optical performance. In particular, in mobile phones with camera functions that have become widespread in recent years, this problem is regarded as important because they are often used in a state where they are susceptible to external impact forces.

  Therefore, for example, the floating mode in which the lens optical system is supported with play (for example, in a state where it can move within a predetermined range) with respect to the camera body, and the lens optical system is fixed so as not to move relative to the camera body. A technique has been proposed in which the fixed mode is switched in conjunction with ON / OFF of a power switch (for example, Patent Document 1 below). In other words, when the floating mode is set, the impact force acting on the lens optical system is mitigated, and when the fixed mode is set, the optical performance is ensured by avoiding the positional deviation between the camera body and the lens optical system. It is a technology.

Further, as a method of positioning the lens optical system with high accuracy with respect to the camera body, a method of moving the lens optical system by a magnetic force has been proposed (for example, Patent Document 2 below).
JP 2004-333614 A JP-A-4-86714

  However, in the above-mentioned Patent Document 1, the mode for reducing the impact force acting on the lens optical system, that is, the floating mode is effective only when the power switch is in the OFF state, and always when the power switch is in the ON state. Fixed mode. That is, the impact force acting on the lens optical system cannot be reduced when the power switch is in the ON state. Therefore, if the camera is dropped with the power switch turned on, a large impact force may act on the lens optical system and be damaged. In particular, in the case of the mobile phone with the camera function, since the power switch is generally always in an ON state (standby state), there is a high possibility of causing a situation such as dropping in the fixed mode. It is difficult to benefit from features that can be switched to mode.

  The present invention has been made in view of the above points, and an object of the present invention is to ensure the impact resistance performance of the lens optical system regardless of the state of the camera (for example, the state of the power switch), and in the photographing state. It is another object of the present invention to provide a lens holding means capable of exhibiting sufficient impact resistance performance.

  The solution means of the present invention taken to achieve the above object is premised on the lens holding means for holding the lens inside the lens barrel. With respect to this lens holding means, a magnetic attraction means for holding the lens on the lens barrel by a magnetic attraction force, a detection means for detecting acceleration or vibration, and an output signal from the detection means are received to detect acceleration or vibration. Adjusting means for adjusting the magnetic attraction force by the magnetic attraction means based on the output signal in the case.

  Further, the adjusting means can be adjusted between a strong holding state in which the magnetic attractive force between the lens and the lens barrel is set relatively high and a weak holding state in which the magnetic attractive force is set relatively low. It has become.

  When applied to the lens holding means mounted on the photographing device, the lens is held in a strong holding state during shooting and the lens is held in a weak holding state when not shooting, while the detection means detects acceleration or vibration during the shooting. At this time, the adjusting means is configured to shift the lens from the strong holding state to the weak holding state.

  Due to these specific matters, when the photographic equipment is dropped while the optical performance of the photographic equipment (camera etc.) is guaranteed with the lens held strong, the detection means detects the acceleration, and this Accordingly, the adjustment means reduces the magnetic attraction force by the magnetic attraction means to shift the lens from the strong holding state to the weak holding state. For this reason, even when the shooting device collides with the ground and an impact force is applied, the lens can be moved, that is, since the play of the lens is secured, it is possible to absorb the impact sufficiently and Damage can be avoided.

  Further, as described above, when the lens is moved from the strong holding state to the weak holding state and returned from the state in which the lens is movable to the photographing state of the photographing apparatus, the magnetic attractive force is increased from the weak holding state. Try to shift to the strong holding state. Thereby, it is possible to quickly return to the shooting state.

  Further, when the adjusting means controls the magnetic attraction force by the magnetic attraction means in a multistage manner between the strong holding state and the weak holding state based on the acceleration or vibration signal detected by the detecting means. The lens can be provided with an appropriate holding force in accordance with the impact force acting on the lens. For example, when the impact force is relatively small, the lens holding force is slightly smaller than the above-mentioned strong holding state (the lens is held with a holding force intermediate between the strong holding state and the weak holding state), so that the impact action is achieved. The subsequent return to the shooting state can be further accelerated.

  Specifically, the following two configurations can be given as configurations for holding the lens inside the lens barrel. First, an iron piece is provided on the outer periphery of the lens, and the magnetic attraction means is a coil embedded in the lens barrel. Then, by applying a voltage to this coil, a magnetic attraction force is applied to the iron piece to hold the lens inside the lens barrel.

  Further, an iron piece is provided on the outer peripheral portion of the lens, and the magnetic attraction means is a permanent magnet supported so as to be able to approach and separate from the outer peripheral portion of the lens. The permanent magnet is brought close to the outer peripheral portion of the lens so that a magnetic attractive force acts on the iron piece to hold the lens inside the lens barrel.

  In addition, when a cushioning material is disposed in the movable range of the lens when the magnetic attractive force is weakened, the lens is directly applied to the inner surface of the lens barrel when the lens is moved by an external impact force in the weakly held state. It does not collide with the shock absorber, but collides with the cushioning material. For this reason, the impact force is absorbed and relaxed by the cushioning material, and the impact force acting on the lens can be greatly relaxed.

  In the present invention, the holding force of the lens can be appropriately controlled with respect to the expected impact force by detecting acceleration and vibration. For this reason, it is possible to instantaneously shift from the strong holding state of the lens to the weak holding state, and the impact force on the lens can be reduced.

  In addition, in a non-shooting state, the lens is in a weakly held state without being energized, that is, in a state where the impact can be mitigated. Therefore, it is not necessary to energize the means for detecting acceleration and vibration, thus realizing power saving. It is also possible.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

(First embodiment)
First, a first embodiment of the present invention will be described with reference to FIGS. 1 and 2. The lens holding mechanism (lens holding means) in this embodiment is applied to an optical system such as a camera.

  1 and 2 show the holding state of the lens 13, and FIG. 1 is a longitudinal sectional view as seen from a direction orthogonal to the optical axis (a sectional view at a position corresponding to the line II in FIG. 2). FIG. 2 is a cross-sectional view seen from the direction along the optical axis.

  As shown in FIGS. 1 and 2, the lens holding mechanism takes a form in which the lens 13 is held in the internal space of a lens barrel 11 having a hollow cylindrical shape. That is, the lens 13 is held so that the axis of the lens barrel 11 and the optical axis of the lens 13 are substantially coincident.

  Here, the lens barrel 11 is formed of a material that is not affected by the magnetic force, such as plastic. In addition, as an apparatus (magnetic force generator) capable of generating a magnetic force on the inner surface of the lens barrel 11, for example, a coil 12 is embedded, and the magnetic force is generated by energizing the coil 12. ing. A voltage controller 15 for controlling the voltage applied to the coil 12 is connected to the magnetic force generator. This voltage control device 15 has a built-in control system (not shown) that can control the applied voltage according to the received signal. An acceleration sensor 16 is connected to the voltage control device 15. The acceleration sensor 16 is a device that can output a signal corresponding to the detected acceleration when the acceleration is detected, for example, when the camera falls, and outputs a signal based on the detected acceleration to the voltage control device 15. It is possible.

  Further, as shown in FIG. 2, the embedding positions of the coil 12 inside the lens barrel 11 are equally spaced on the inner peripheral surface of the lens barrel 11 in the circumferential direction (in the case shown in FIG. ). The coil 12 may be disposed on the entire inner periphery of the lens barrel 11. On the other hand, with respect to the lens 13, a substance that strongly reacts to a magnetic attractive force, such as an iron piece 14, is adhered at four positions on the outer peripheral surface at equal intervals in the circumferential direction. The arrangement position of the iron piece 14 may be arranged on the entire outer periphery of the lens 13. As a result, when the coil 12 inside the lens barrel 11 is energized to generate a magnetic force, the iron piece 14 of the lens 13 receives a strong magnetic attraction force with respect to each coil 12, and as a result, the lens. 13 is configured to be strongly fixed inside the lens barrel 11 (strongly fixed at a position where the iron piece 14 faces the coil 12: strong holding described later).

  Further, when the lens 13 is not fixed to the inner surface of the lens barrel 11 (the state in which the lens 13 can freely move inside the lens barrel 11: weak holding described later). Restriction protrusions 17 and 17 for restricting the movement range are formed at positions at a predetermined interval in the longitudinal direction of the lens barrel 11.

  Next, the operation of the lens holding mechanism described above will be described.

  In the lens holding mechanism shown in FIGS. 1 and 2, the voltage control device 15 and the acceleration sensor 16 are not energized except in a shooting state. That is, the lens 13 is not held by the magnetic attraction force except in the photographing state, and can move freely in the optical axis direction in the partitioned space (within the range of regulation by the regulation protrusions 17 and 17). Yes. Therefore, even if the lens 13 receives an impact force from the outside in this state, the lens 13 can move, that is, the play of the lens 13 is ensured, so that sufficient impact absorption can be performed. .

  On the other hand, in the photographing state, that is, when the power of the camera or the like is turned on, a voltage is applied from the voltage control device 15 to the coil 12 for holding the lens 13 in conjunction with the power on. As a result, the lens 13 is strongly held at the position facing the coil 12 by the magnetic attraction force, and the lens 13 is accurately positioned at a position where the optical performance is guaranteed, and can shift to the photographing state.

  For example, when the user drops the camera in the shooting state, the acceleration sensor 16 detects the fall (acceleration of gravity). The detection signal is input to the voltage control device 15, and a signal that weakens the magnetic attractive force is output from the voltage control device 15 to the coil 12. As a result, the lens 13 instantaneously shifts from the strong holding state to the weak holding state. However, if the detection signal input to the voltage control device 15 is below a certain threshold value, it is determined that the applied impact force is small, and no signal is output to the coil 12. In other words, the strong holding state is maintained by slight vibrations and shocks, thereby suppressing the frequent occurrence of the phenomenon that the camera is ready to shoot (the lens 13 can move freely). is doing.

  When the weak holding state is entered, the lens 13 can move freely within the bounded range. In this state, even if an impact force is applied from the outside, the impact can be reduced within the range of play of the lens 13, so that when the camera collides with the ground due to a fall and the impact force is applied, the lens 13 It is possible to suppress damage to the lens and damage due to collision between the lens 13 and the lens barrel 11.

  After the impact is stopped, the power control device 15 starts to apply power again, and the lens 13 can be pulled back to the predetermined position by the magnetic attractive force, and can return to the strong holding state again. The timing of the transition to the imaging state by the application of power is on condition that the acceleration sensor 16 does not detect acceleration or does not exceed a certain threshold value.

  In the present embodiment, the voltage control device 15 may change the voltage applied to the coil in multiple stages according to the detection signal from the acceleration sensor 16 (in accordance with the magnitude of the detected acceleration). That is, the holding force of the lens 13 may be changed in a multistage manner between the strong holding state and the weak holding state. As a result, an optimum voltage can be applied to an impact expected from a signal detected by the acceleration sensor 16. That is, the holding force of the lens 13 can be optimally controlled. As a result, when the expected impact is weak, the holding force is set to about halfway between the strong holding and the weak holding, so that the movable amount of the lens 13 is reduced when the impact is received. Therefore, it is possible to smoothly return to the photographing state by setting the strong holding state after the impact disappears. On the other hand, when a large acceleration is detected, the range of play of the lens 13 is widened by setting the weak holding force or the weak holding state to release the holding force, and the impact can be sufficiently mitigated.

(Second Embodiment)
Next, a second embodiment of the present invention will be described with reference to FIGS. The lens holding mechanism (lens holding means) in this embodiment is also applied to an optical system such as a camera. The lens holding mechanism according to the present embodiment is characterized by the inner surface structure of the lens barrel 11, and other configurations and operations for holding the lens are substantially the same as those in the first embodiment described above. Accordingly, only differences from the first embodiment will be described here.

  3 and 4 show the holding state of the lens 13 in the present embodiment. FIG. 3 is a longitudinal sectional view seen from a direction orthogonal to the optical axis, and FIG. 4 is seen from the direction along the optical axis. FIG. 4 is a cross-sectional view showing a cross-section at a position corresponding to line IV-IV in FIG. 3.

  As shown in FIGS. 3 and 4, a buffer material 18 made of an elastic material such as rubber is provided on the entire movable range of the lens 13, that is, on the entire inner surface of the lens barrel 11 between the restriction protrusions 17 and 17. Is provided. The height of the cushioning material 18 is set to be large at the portion facing the regulating protrusion 17. Further, the thickness dimension of the buffer material 18 and the height dimension of the iron piece 14 are set so that a slight gap is formed between the iron piece 14 attached to the outer peripheral portion of the lens 13 and the buffer material 18. ing. Other configurations and control of the applied voltage to the coil 12 are substantially the same as those of the first embodiment described above.

  In the case of the present embodiment, since the buffer material 18 is provided on the inner surface of the lens barrel 11, when an external impact force acts on the lens 13 in the weakly held state, the iron piece 14 becomes the lens barrel. The iron piece 14 does not directly collide with the inner surface of the eleventh piece, but collides with the cushioning material 18. For this reason, the impact force is absorbed and relaxed by the buffer material 18, and the impact force acting on the lens 13 can be greatly relaxed.

  In addition, when the expected impact is weak, it is considered that the lens 13 is not damaged by the impact even if the movable range of the lens 13 is reduced. Therefore, the holding force is reduced without reducing the holding force to the weak holding state. By holding the lens 13, it is possible to smoothly return to the photographing state by setting the strong holding state after the impact disappears. On the other hand, when a large acceleration is detected, the range of play of the lens 13 is widened by setting the weak holding force or the weak holding state to release the holding force, and the impact can be sufficiently mitigated.

(Third embodiment)
Next, a third embodiment of the present invention will be described with reference to FIGS. The lens holding mechanism (lens holding means) in this embodiment is also applied to an optical system such as a camera. The lens holding mechanism according to the present embodiment is a modification of the means for generating a magnetic force, and other configurations are substantially the same as those of the first embodiment described above. Accordingly, only differences from the first embodiment will be described here.

  5 and 6 show the holding state of the lens 13 in the present embodiment. FIG. 5 is a longitudinal sectional view seen from a direction orthogonal to the optical axis, and FIG. 6 is seen from the direction along the optical axis. FIG. 6 is a sectional view taken along the line VI-VI in FIG. 5.

  As shown in FIGS. 5 and 6, the lens barrel 11 has four permanent magnets 20 arranged at equal intervals on the inner circumference thereof, each of which is provided with a lens barrel wall surface by a lead screw 21 and a motor 22. It is possible to move in a direction perpendicular to the iron piece (a direction toward and away from the iron piece 14). A voltage control device 15 is connected to the motor 22. The voltage control device 15 can change the output to the motor 22 in accordance with a signal input from the outside. By changing the output of the motor 22, the permanent magnet 20 can move in a direction perpendicular to the inner wall surface of the lens barrel 11 via the lead screw 21. That is, the magnetic attractive force with respect to the lens 13 increases as the permanent magnet 20 approaches the lens 13. Further, as the shape of the permanent magnet 20, a ring-shaped permanent magnet that covers the inner wall of the lens barrel 11 may be used.

  With such a configuration, when each permanent magnet 20 approaches the lens 13, a strong magnetic attractive force acts on the iron piece 14, and as a result, the lens 13 is strongly held.

  Further, in the present embodiment, the buffer material 23 is provided on the side surface of the restriction projection 17 (the portion where the lens 13 or the iron piece 14 may collide in the weakly held state). By reducing the absorption, the impact force acting on the lens 13 can be greatly reduced.

  In the case of this embodiment, energization is not performed to the voltage control device 15 and the acceleration sensor 16 except for the shooting state. Then, each permanent magnet 20 is retracted to a position away from the lens 13 and the iron piece 14, thereby putting the lens 13 in a weakly held state. In other words, the lens 13 is not held by the magnetic attraction force except in the photographing state, and can move freely in the optical axis direction in a partitioned space (within the range of regulation by the regulation protrusions 17 and 17). ing. Therefore, even if the lens 13 receives an impact force from the outside in this state, the lens 13 can move, that is, the play of the lens 13 is ensured, so that sufficient impact absorption can be performed. ing. Also, the shock absorbing material 23 performs good shock absorption.

  On the other hand, in the shooting state, that is, when the camera is turned on, a voltage is applied from the voltage control device 15 to the motor 22 in conjunction with the power-on, thereby driving the lead screw 21 and the permanent magnet. 20 approaches the lens 13. As a result, the lens 13 is strongly held at a position facing the permanent magnet 20 by the magnetic attraction force, and is accurately positioned at a position where the optical performance is guaranteed, and can shift to the photographing state.

  For example, when the user drops the camera in the shooting state, the acceleration sensor 16 detects the fall (acceleration of gravity). The detection signal is input to the voltage control device 15, and a signal for reducing the magnetic attraction force is output from the voltage control device 15 to the motor 22. As a result, the lead screw 21 is driven and the permanent magnet 20 moves away from the lens 13, and the lens 13 shifts from the strong holding state to the weak holding state. However, when the detection signal input to the voltage control device 15 is below a certain threshold, it is determined that the applied impact force is small, and no signal is output to the motor 22. In other words, the strong holding state is maintained by slight vibrations and shocks, thereby suppressing the frequent occurrence of the phenomenon that the camera is ready to shoot (the lens 13 can move freely). is doing.

  When the weak holding state is entered, the lens 13 can move freely within the bounded range. In this state, even if an impact force is applied from the outside, the impact can be reduced within the range of play of the lens 13, so that when the camera collides with the ground due to a fall and the impact force is applied, the lens 13 It is possible to suppress damage to the lens and damage due to collision between the lens 13 and the lens barrel 11. Other configurations are substantially the same as those of the first embodiment described above.

-Other embodiments-
In each of the embodiments described above, the case where the lens holding mechanism according to the present invention is applied to the optical system of the camera has been described. The present invention is not limited to this, and can also be applied to a lens unit mounted on a mobile phone with a camera function.

It is the longitudinal cross-sectional view which showed the lens holding mechanism which concerns on 1st Embodiment, and was seen from the direction orthogonal to an optical axis. It is sectional drawing which showed the lens holding mechanism which concerns on 1st Embodiment, and was seen from the direction in alignment with an optical axis. FIG. 6 is a view corresponding to FIG. 1 illustrating a lens holding mechanism according to a second embodiment. FIG. 9 is a view corresponding to FIG. 2 illustrating a lens holding mechanism according to a second embodiment. FIG. 10 is a view corresponding to FIG. 1 illustrating a lens holding mechanism according to a third embodiment. FIG. 9 is a view corresponding to FIG. 2 illustrating a lens holding mechanism according to a third embodiment.

Explanation of symbols

11 Lens barrel 12 Coil (magnetic attraction means)
13 Lens 15 Voltage control means (adjustment means)
16 Acceleration sensor (detection means)
18, 23 Buffer material 20 Permanent magnet (magnetic attraction means)

Claims (8)

In the lens holding means for holding the lens inside the lens barrel,
Magnetic attraction means for holding the lens in a lens barrel by magnetic attraction;
Detection means for detecting acceleration or vibration;
Lens holding means, comprising: an adjusting means for receiving an output signal from the detecting means and adjusting a magnetic attractive force by the magnetic attractive means based on an output signal when acceleration or vibration is detected. In the lens holding means according to claim 1,
The adjusting means is configured to be adjustable between a strong holding state in which the magnetic attractive force between the lens and the lens barrel is set to be relatively high, and a weak holding state in which the magnetic attractive force is set to be relatively low. A lens holding means. In the lens holding means according to claim 2,
It is mounted on the shooting equipment,
The adjustment means places the lens in a strong holding state during shooting and places the lens in a weak holding state during non-shooting, while changing the lens from the strong holding state to the weak holding state when the detection means detects acceleration or vibration during shooting. A lens holding means that is configured to shift. In the lens holding means according to claim 2 or 3,
A lens holding means characterized in that a magnetic holding force is increased from a weak holding state to shift to a strong holding state. In the lens holding means according to claim 2, 3 or 4,
The adjusting means is configured to control the magnetic attraction force by the magnetic attraction means in a multistage manner between a strong holding state and a weak holding state based on an acceleration or vibration signal detected by the detecting means. Lens holding means. In the lens holding means according to any one of claims 1 to 5,
An iron piece is provided on the outer peripheral portion of the lens, and the magnetic attraction means is a coil embedded in the lens barrel. By applying a voltage to this coil, a magnetic attraction force is applied to the iron piece to make the lens A lens holding means characterized in that the lens holding means is held inside the lens barrel. In the lens holding means according to any one of claims 1 to 5,
An iron piece is provided on the outer peripheral portion of the lens, and the magnetic attraction means is a permanent magnet supported so as to be able to approach and separate from the outer peripheral portion of the lens, and this permanent magnet is brought close to the outer peripheral portion of the lens. The lens holding means, wherein the lens is held inside the lens barrel by applying a magnetic attractive force to the iron piece. In the lens holding means according to any one of claims 1 to 7,
A lens holding means, wherein a buffer material is arranged in a movable range of the lens when the magnetic attractive force is weakened.

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