JP2006308703A - Lens barrier device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To enable smooth operation by lightening the driving load of a lens barrier device. <P>SOLUTION: The lens barrier device is equipped with a base 10 demarcating an aperture part 10a; barrier blades 20 and 30 supported so as to be freely rocked on the front 10b of the base 10 and opening/shutting the aperture part 10a; a driving ring 40, supported so as to be freely turned on the back surface 10c of the base 10, having a cam part 42 converting pressing force F in an optical axis direction L into rotational force and driving the barrier blades 20 and 30 to open/shut; and a coil spring 70 energizing the driving ring 40 in a direction where the barrier blades 20 and 30 are opened. The driving ring 40 has a locking piece 45 locking one end 71 of the coil spring 70 in the vicinity of the cam part 42, and the base 10 has a locking piece 14 locking the other end 72 of the coil spring 70 so as to provide the coil spring 70, in a tensioned state in substantially the tangential direction T of the driving ring 40. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a lens barrier device for protecting a lens of a camera such as a digital still camera or a digital video camera, and in particular, the barrier blade is driven to open and close by a drive ring that rotates around the optical axis by an external force acting in the optical axis direction of the lens. The present invention relates to a lens barrier device.

  In a camera, a conventional lens barrier device that opens and closes the front surface of the lens includes a presser ring that presses the lens positioned at the forefront, a drive ring that is rotatably supported with respect to the presser ring, and an opening disposed in front of the drive ring. A base (barrier support frame) having a portion, a pair of barrier blades supported in a swingable manner on the front surface of the base, a coil spring that urges the drive ring in the direction in which the barrier blades open, There is known one provided with a cover having an open portion.

In this device, the drive ring extends from the outer peripheral edge toward the rear in the optical axis direction, and has a linearly inclined cam surface that converts the pressing force in the optical axis direction into a rotational force, and penetrates the base. In this way, an engagement portion (drive pin) that protrudes forward in the optical axis direction and engages the barrier blade is provided. When the cam portion receives a pressing force (external force) in the optical axis direction, the drive ring When the barrier blade is rotated to be released and released from the pressing force, the driving ring is reversely rotated by the urging force of the coil spring to open the barrier blade (see, for example, Patent Document 1).
JP 2002-40516 A

By the way, in this apparatus, since the barrier blade is disposed behind the base with the drive ring as the front, the pressing force in the optical axis direction acting on the cam portion does not directly reach the barrier blade (by pressing the barrier blade). However, since the drive ring is supported by surface contact with the base, its sliding resistance increases and the drive load increases.
In addition, since the coil spring that biases the drive ring in the direction in which the barrier blade opens is curved and stretched in the circumferential direction of the drive ring, the component force of the spring force biases the drive ring in the radial direction, The sliding resistance between the presser ring and the drive ring forming the radial bearing is increased, and the drive load is similarly increased.

Further, as shown in FIGS. 11A and 11B, the cam portion 1a provided on the drive ring 1 is formed as a linear cam surface having an inclination angle θ. Therefore, when the drive ring 1 is rotated from the fully open position to the fully closed position while bringing the pressing member P into contact with the cam portion 1a and exerting a pressing force F in the optical axis direction and resisting the spring force Fs of the coil spring 2, As shown in FIGS. 11A and 11B and FIGS. 12A and 12B, F = tan ² θ · k · Lc (where θ is a constant angle at which the pressing member P contacts the cam surface 1a). , K is a spring constant of the coil spring 2 and Lc is a displacement amount of the pressing member P), when the spring force Fs increases from Fso to Fsc, it is necessary to increase the pressing force F accordingly from 0 to the maximum value Fc. is there.
Therefore, a large driving force is required to move the pressing member P relatively, leading to an increase in the size of the drive source, an increase in power consumption, an increase in the size of the apparatus, and the like.

  The present invention has been made in view of the above circumstances, and its object is to open and close barrier blades with a drive ring that converts external force (for example, pressing force) acting in the optical axis direction into rotational drive force. In a lens barrier device to be driven, a lens barrier device capable of ensuring a smooth opening / closing operation by reducing driving load while simplifying the structure, thinning, miniaturization, low power consumption, easy assembly, etc. It is to provide.

  The lens barrier device of the present invention includes a base that is disposed in front of the lens to define an opening, a barrier blade that is swingably supported on the front surface of the base and opens and closes the opening, and is rotatable to the rear surface of the base. A drive ring that has a cam portion that is supported on the optical axis and converts a pressing force in the optical axis direction into a rotational force and that opens and closes the barrier blade, and a coil spring that biases the drive ring in the direction in which the barrier blade opens. In the barrier device, the drive ring has a latch piece that latches one end of the coil spring in the vicinity of the cam portion, and the base is a coil spring that stretches the coil spring in a substantially tangential direction of the drive ring. It has the latching piece which latches the other end of this.

According to this configuration, the barrier blade is supported on the front surface of the base and the drive ring is supported on the rear surface of the base, and the coil spring is formed by the engagement piece provided near the cam portion and the engagement piece provided on the base. Since it is stretched in the tangential direction of the drive ring, it is possible to prevent the pressing force exerted on the cam portion from affecting the barrier blade, and the rotational driving force and the coil spring that rotate the drive ring by the pressing force exerted on the cam portion. Therefore, the normal load that presses the drive ring in the radial direction can be eliminated or reduced, and the drive ring can be smoothly rotated, that is, the barrier blade can be opened and closed smoothly.
Therefore, generation of unnecessary frictional force or the like can be prevented or suppressed, and the driving force can be reduced, that is, the driving source can be reduced in size, the power consumption can be reduced, and the apparatus can be reduced in size.

In the above configuration, the cam portion may have a cam surface that is curved to rotate the drive ring with a substantially constant pressing force with respect to an increase in the spring force of the coil spring.
According to this configuration, when the drive ring is rotated against the spring force of the coil spring to move the barrier blade from the fully open position to the fully closed position, even if the spring force of the coil spring increases, a substantially constant pressing force is achieved. The drive ring can be rotated by simply applying pressure. Accordingly, the driving force can be reduced, and the driving source can be downsized, the power consumption can be reduced, and the apparatus can be downsized.

In the above-described configuration, the barrier blade may employ a configuration having an engaged portion that engages with the engaging portion of the drive ring in the vicinity of the supported portion that is swingably supported with respect to the base. .
According to this configuration, since the engaging portion of the drive ring engages with the engaged portion provided in the vicinity of the supported portion of the barrier blade and exerts an opening / closing driving force, the barrier blade is bent or bent. The barrier blades can be smoothly opened and closed.

In the above configuration, a torsion spring that urges the barrier blade in the closing direction is arranged around the supported portion, and the torsion spring is linearly formed at one end and hooked to the base, and the other end is annular. It is possible to adopt a configuration that is formed on the outer blade and hooked on a pin provided on the barrier blade.
According to this configuration, one end of the torsion spring is hooked to the base and the other end is hooked to the pin of the barrier blade by external fitting, so that the torsion spring can be easily attached and prevented from tilting. It can be done reliably.

In the above configuration, the barrier blade includes a first barrier blade and a second barrier blade that open and close the opening in cooperation with each other, and the drive ring is arranged at the substantially bisecting position in the circumferential direction. A latch piece that has a first engagement portion that engages with the engaged portion of the second barrier blade and a second engagement portion that engages with the engaged portion of the second barrier blade, and latches one end of the cam portion and the coil spring. Can adopt a configuration provided in a substantially intermediate region between the first engaging portion and the second engaging portion in the circumferential direction.
According to this configuration, the drive ring drives the first barrier blade and the second barrier blade to open and close by the first engagement portion and the second engagement portion, which are located approximately 180 ° apart in the circumferential direction, respectively. . At this time, since the cam portion is at a substantially intermediate position between the first engaging portion and the second engaging portion, the pressing force exerted on the cam portion is evenly distributed as a rotational driving force without being biased, and the first barrier is provided. The blade and the second barrier blade can be smoothly opened and closed.

  As described above, according to the lens barrier device of the present invention, in the lens barrier device that opens and closes the barrier blades with the drive ring that converts the pressing force acting in the optical axis direction into the rotational driving force, the structure is simplified and thinned. The drive load can be reduced and a smooth opening / closing operation can be ensured while achieving reductions in size, size, power consumption, and ease of assembly.

DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, exemplary embodiments of the invention will be described with reference to the accompanying drawings.
1 to 10 show an embodiment of a lens barrier device according to the present invention. FIG. 1 is an exploded perspective view of the device, FIG. 2 is a rear perspective view of the device, and FIG. 3 is a rear view of the device. 4 and 5 are front and rear views showing the relationship between the drive ring and the barrier blade, FIG. 6 is a perspective view showing the barrier blade and the torsion spring, and FIGS. 7 and 8 explain the operation of the cam portion of the drive ring. FIG. 9, FIG. 9 and FIG. 10 are rear perspective views showing a state in which the barrier blade is in the fully open position and the fully closed position.

  As shown in FIGS. 1 to 3, the lens barrier device includes a base 10 that defines an opening 10a, first barrier blades 20 and second barrier blades that are swingable with respect to the base 10. The blade 30, the drive ring 40 that drives the opening and closing of the first barrier blade 20 and the second barrier blade 30, and the first barrier blade 20 and the second barrier blade 30 are connected to the base 10 so as to cover and define an opening 50 a. Two torsion springs 60 urging the cover 50, the first barrier blade 20 and the second barrier blade 30 in the closing direction, and the drive ring 40 to drive the first barrier blade 20 and the second barrier blade 30 in the opening direction. An urging coil spring 70 and the like are provided.

  As shown in FIGS. 1 to 3, the base 10 is formed in an annular shape so as to define a circular opening 10a using a resin material, and the first barrier blade 20 and the second barrier are formed on the front surface 10b. The two supporting shafts 11 that support the blade 30 in a swingable manner, the latching piece 12 that latches one end 61 of the torsion spring 60, and the rear surface 10c define an inner peripheral surface of the opening 10a and are arranged in the optical axis direction L. Cylindrical portion 13 projecting rearward, four regulating pieces 13a that are provided on the cylindrical portion 13 and regulate the dropout of the drive ring 40 by a bayonet type, the latching piece 14 that latches the other end 72 of the coil spring 70, and the support shaft 11 is provided with a through hole 15 or the like opened in the vicinity of 11.

Further, the base 10 includes a pin 16 for positioning the cover 50, a hole 17 used for attachment to a lens barrel, a protrusion 18 for connecting the cover 50 by snap fitting, and the like.
Here, since the base 10 supports the first barrier blade 20 and the second barrier blade 30 in a swingable manner on the front surface 10b and supports the drive ring 40 in a pivotable manner on the rear surface 10c, the drive ring 40 (to be described later). The pressing force F in the optical axis direction L exerted on the cam portion 42) directly received by the rear surface 10c of the base 10 does not reach the first barrier blade 20 and the second barrier blade 30 and prevents deformation or bending thereof. it can.

The first barrier blade 20 and the second barrier blade 30 are formed of a resin material in a thin plate shape or a thin metal plate, and as shown in FIGS. 1, 4 to 6, the support shaft 11 of the base 10. Is supported by the first and second engaging portions 43 and 44 of the drive ring 40, which are formed to protrude in parallel in the vicinity of the supported portion 21. The engaging portions 22 and 32 to be mated with each other, and pins 23 and 33 which are formed to protrude in parallel in the vicinity of the supported portions 21 and 31 and to which the other end 62 of the torsion spring 60 is externally fitted and hooked are provided. .
Here, since the engaged portions 22 and 32 are formed in the vicinity of the supported portions 21 and 31 supported so as to be swingable with respect to the base 10, the first engaging portion 43 of the drive ring 40 and When the second engaging portion 44 engages with the engaged portions 22 and 32 and exerts an opening / closing driving force, a bending moment or the like is not applied, and the first barrier blade 20 and the second barrier blade 30 are bent or bent. Can be prevented, and a smooth opening and closing operation becomes possible.

  The drive ring 40 is made of a resin material, and is formed in an annular shape so as to be slidably supported with respect to the rear surface 10c of the base 10 and the outer peripheral surface of the cylindrical portion 13, as shown in FIGS. The annular portion 41, the cam portion 42 projecting rearward from the annular portion 41 in the optical axis direction L, and the first barrier blade 20 and the second barrier blade 30 engaged from the annular portion 41 projecting forward in the optical axis direction. The first engagement portion 43 and the second engagement portion 44 that engage with the portions 22 and 32, the engagement piece 45 that engages one end 71 of the coil spring 70, and the restriction piece 13a in the state of being assembled to the base 10 are removed. Four regulated parts 46 to be regulated are provided.

For example, when the lens barrier device is attached to the front end of a lens barrel of a camera, the cam portion 42 has a pressing member P provided on the camera side on the cam surface 42a as the lens barrel retracts. It is designed to engage.
That is, when a pressing force (external force) F toward the front in the optical axis direction L is applied to the cam portion 42, the pressing force F moves the drive ring 40 around the optical axis L via the cam action of the cam surface 42a. The drive ring 40 is rotated about the optical axis L against the spring force Fs of the coil spring 70.

Here, the cam piece 42 and the hooking piece 45 for hooking the one end 71 of the coil spring 70 are disposed in the vicinity in the circumferential direction of the drive ring 40 as shown in FIGS. Further, as shown in FIG. 3, the latching piece 14 that latches the other end 72 of the coil spring 70 is substantially tangent to the drive ring 40 in a state where the one end 71 and the other end 72 of the coil spring 70 are latched. It is provided at a position stretched in the direction T.
As a result, as shown in FIG. 3, the rotational driving force Fr of the drive ring 40 generated by the pressing force F in the optical axis direction L exerted on the cam portion 42 and the spring force Fs of the coil spring 70 antagonize in a substantially linear shape. The normal load Fn that presses the drive ring 40 in the radial direction can be minimized. Therefore, the drive ring 40 can be smoothly rotated. Therefore, the first barrier blade 20 and the second barrier blade 30 can be smoothly opened and closed, and unnecessary frictional force and the like are prevented from being generated. Thus, the driving force can be reduced, that is, the driving source can be reduced in size, the power consumption can be reduced, and the apparatus can be reduced in size.

Further, the cam portion 42 has a curved cam surface 42 a that protrudes toward the pressing member P so as to rotate the drive ring 40 with a substantially constant pressing force F with respect to an increase in the spring force Fs of the coil spring 70.
That is, the pressing member P is brought into contact with the cam surface 42 a of the cam portion 42 to exert a pressing force F in the optical axis direction L, and resists the spring force Fs of the coil spring 70, while the drive ring 40 is in the fully open position (the pressing member P 7a, 7b, 8a, and 8b when rotating from the angle θo that contacts the cam surface 42a to the fully closed position (the angle θc that the pressing member P contacts the cam surface 42a). F = tan ² θ · k · Lc (where θ is the angle with which the pressing member P comes into contact with the cam surface 42a while moving and gradually decreases from θo toward θc, and k is the spring of the coil spring 70) Due to the relationship between the constant, Lc, the amount of displacement of the pressing member P), even if the spring force Fs increases from Fso to Fsc, the driving ring 40 is rotated only by applying a substantially constant pressing force Fc as the pressing force F. Can do. Accordingly, the driving force can be reduced, and the driving source can be downsized, the power consumption can be reduced, and the apparatus can be downsized.

Further, in the drive ring 40, as shown in FIGS. 1, 4, and 5, a first engagement that engages with the engaged portion 22 of the first barrier blade 20 at a position that is substantially equally divided in the circumferential direction. The engaging portion 43 and the second engaging portion 44 that engages with the engaged portion 32 of the second barrier blade 30 are provided, and the engaging piece 45 that engages the cam portion 42 and one end 71 of the coil spring 70 is provided. It is provided in a substantially intermediate region between the first engaging portion 43 and the second engaging portion 44 in the circumferential direction.
According to this, the first barrier blade 20 and the second barrier via the first engagement portion 43 and the second engagement portion 44 located at a position approximately 180 ° apart by the pressing force F exerted on the cam portion 42. When the blade 30 is driven to open and close, the pressing force F exerted on the cam portion 42 is evenly distributed as the rotational driving force Fr without being biased, and the first barrier blade 20 and the second barrier blade 30 are smoothly opened and closed. Can be made.

  The coil spring 70 urges the drive ring 40 in the direction in which the first barrier blade 20 and the second barrier blade 30 open. As shown in FIG. 3, one end 71 is the latching piece 45 of the drive ring 40. The other end 72 is hooked on the hooking piece 14 of the base 10, so that a tensile force is exerted only in the tangential direction T of the driving ring 40 without contacting the driving ring 40.

The torsion spring 60 urges the first barrier blade 20 and the second barrier blade 30 in the closing direction, and is formed so as to generate an urging force smaller than the urging force of the coil spring 70. Further, as shown in FIGS. 1, 5 and 6, the torsion spring 60 has one end 61 formed in a straight line and hooked on the hooking piece 12 of the base 10, and the other end 62 formed in an annular shape. The pins 23 and 33 provided on the first barrier blade 20 and the second barrier blade 30 are externally fitted and hooked.
Therefore, even when the first barrier blade 20 and the second barrier blade 30 are opened and closed, the other end 62 is hooked on the pins 23 and 33 by the external fitting, so that the first barrier blade 20 and the second barrier blade 30 are securely hooked and dropped off. Therefore, it is possible to prevent the torsion spring 60 from being inclined and the like, and the attachment thereof can be performed easily and reliably.

  As shown in FIG. 1, the cover 50 is formed in a disk shape from a resin material, has a substantially rectangular opening 50 a at the center, and extends from the outer periphery toward the rear in the optical axis direction L. 10 is provided with a latch piece 51 snap-fitted to the projection 18, two positioning holes 52 through which the pins 16 of the base 10 are passed, and a hole 53 used for attachment to a lens barrel or the like. The cover 50 cooperates with the base 10 to define a blade chamber that houses the first barrier blade 20 and the second barrier blade 30.

  Next, the operation of this apparatus will be described with reference to FIGS. First, as shown in FIG. 9, when the cam portion 42 of the drive ring 40 does not receive a pressing force from the camera side pressing member P or the like, the driving ring 40 is urged by the coil spring 70 to rotate clockwise. Located at the end. At this time, the engaged portions 22 and 32 of the first barrier blade 20 and the second barrier blade 30 resist the urging force of the torsion spring 60, and the first engaging portion 43 and the second engaging blade 43 of the drive ring 40. It is pushed by the engaging portion 44 and is located at a fully open position where the opening 50a of the cover 50 is fully opened.

From this state, when the cam portion 42 of the drive ring 40 receives a pressing force F by the pressing member P or the like on the camera side, the drive ring 40 rotates counterclockwise by a predetermined angle while resisting the biasing force of the coil spring 70. The first engaging portion 43 and the second engaging portion 44 of the drive ring 40 retreat from the engaged portions 22 and 32 of the first barrier blade 20 and the second barrier blade 30 and at the same time, the urging force of the torsion spring 60 Accordingly, the first barrier blade 20 and the second barrier blade 30 rotate and perform a closing operation.
In this closing operation, even if the spring force Fs of the coil spring 70 increases as described above, the drive ring 40 can be rotated only by applying a substantially constant pressing force F (Fc), so that a driving force is generated. The drive source (motor, etc.) can be made small, so that low power consumption, downsizing of the apparatus, etc. can be achieved.

  In the above embodiment, the two barrier blades 20 and 30 are shown as the barrier blades. However, the present invention is not limited to this, and the configuration of the present invention may be adopted in one or more barrier blades. Good.

  As described above, the lens barrier device according to the present invention is not limited to a camera equipped with a retractable lens barrel as long as it is disposed on the front surface of the lens and protects the lens, and other digital still cameras, It can also be used in digital video cameras, silver salt film cameras, and the like.

1 is an exploded perspective view showing an embodiment of a lens barrier device according to the present invention. FIG. 2 is a rear perspective view of the lens barrier device shown in FIG. 1. FIG. 2 is a rear view of the lens barrier device shown in FIG. 1. It is a front view which shows the relationship between the barrier blade | wing which makes a part of lens barrier apparatus, and a drive ring. It is a rear view which shows the relationship between the barrier blade | wing which makes a part of lens barrier device, and a drive ring. (A), (b) is a perspective view which shows the relationship between a barrier blade | wing and a torsion spring. The operation of the cam portion of the drive ring that forms a part of the lens barrier device will be described. (A) is a schematic diagram showing the force relationship in a state where the drive ring is in the fully open position, and (b) is the drive ring. It is a schematic diagram which shows the force relationship in the state in a fully closed position. 2A and 2B illustrate the operation of a cam portion of a drive ring and a coil spring that form a part of a lens barrier device. FIG. 3A is a diagram illustrating changes in spring force with respect to the amount of extension of the coil spring, and FIG. It is a figure which shows the change of the pressing force of the cam part with respect to. It is a back perspective view which shows the state which the barrier blade | wing opened the opening part. It is a back perspective view which shows the state which the barrier blade closed the opening part. In the conventional lens barrier device, the operation of the cam portion of the drive ring will be described. (A) is a schematic diagram showing a force relationship in a state where the drive ring is in a fully open position, and (b) is a diagram showing the entire drive ring. It is a schematic diagram which shows the force relationship in the state in a closed position. In the conventional lens barrier device, the operation of the cam portion of the drive ring and the action of the coil spring will be described. (A) is a diagram showing the change in spring force with respect to the amount of extension of the coil spring, and (b) is the amount of rotation of the drive ring. It is a figure which shows the change of the pressing force of a cam part.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Base 10a Opening part 10b Front surface 10c Rear surface 11 Support axis | shaft 12 Latch piece 13 Cylindrical part 14 Latch piece (Latch piece which latches the other end of a coil spring)
15 through-hole 20 first barrier blade 21 supported portion 22 engaged portion 23 pin 30 second barrier blade 31 supported portion 32 engaged portion 33 pin 40 drive ring 41 annular portion 42 cam portion 42a cam surface 43 first Engagement part 44 Second engagement part 45 Latching piece (Latching piece that latches one end of the coil spring)
50 cover 50a opening 60 torsion spring 61 one end 62 other end 70 coil spring 71 one end 72 other end L optical axis direction P pressing member F pressing force Fs spring force Fr of coil spring rotational driving force T tangential direction of driving ring

Claims (5)

A base that is disposed in front of the lens to define an opening; a barrier blade that is swingably supported on the front surface of the base and opens and closes the opening; and a light that is rotatably supported on the rear surface of the base. A lens barrier device comprising: a drive ring having a cam portion that converts axial pressing force into rotational force; and a drive ring that opens and closes the barrier blade; and a coil spring that biases the drive ring in a direction in which the barrier blade opens. Because
The drive ring has a latch piece that latches one end of the coil spring in the vicinity of the cam portion,
The base has a latching piece for latching the other end of the coil spring so as to stretch the coil spring in a substantially tangential direction of the drive ring.
A lens barrier device. The cam portion has a cam surface curved so as to rotate the drive ring with a substantially constant pressing force with respect to an increase in spring force of the coil spring.
The lens barrier device according to claim 1. The barrier blade has an engaged portion that engages with an engaging portion of the drive ring in the vicinity of a supported portion that is swingably supported with respect to the base.
The lens barrier device according to claim 1, wherein the lens barrier device is a lens barrier device. Around the supported portion, a torsion spring for biasing the barrier blade in the closing direction is disposed,
One end of the torsion spring is formed in a straight line and is hooked on the base, and the other end is formed in an annular shape and is hooked by being externally fitted to a pin provided on the barrier blade.
The lens barrier device according to claim 3. The barrier blade comprises a first barrier blade and a second barrier blade that open and close the opening in cooperation with each other,
The drive ring engages with the engaged portion of the first barrier blade and the engaged portion of the second barrier blade at a position that is substantially equally divided in the circumferential direction. Having a second engaging portion;
A latching piece for latching one end of the cam portion and the coil spring is provided in a substantially intermediate region of the first engagement portion and the second engagement portion in the circumferential direction.
The lens barrier device according to claim 3 or 4, wherein

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