JP2004046242A - Camera - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a camera provided with a lens cover unit which is small in outer diameter, can make a lens barrel narrow and can be formed into a smaller thickness. <P>SOLUTION: A lens cover actuated to be opened and closed by rotational moving, a lens cover base for pivotally supporting the lens cover, a lens covering for opening and closing the lens cover by rotational moving, and a decorative frame for outer packaging and holding the lens covering are arranged, successively from a taking lens side, in front of the taking lens. <P>COPYRIGHT: (C)2004,JPO

Description

The present invention relates to a camera provided with a lens cover.

Conventionally, there are many cameras provided with a lens cover in front of a photographing lens. In addition to the lens cover, a lens cover base for pivotally supporting the rotating lens cover, and a lens cover ring for opening and closing the lens cover by rotating. Etc. are arranged at least. These are arranged in order of a lens cover ring, a lens cover, and a lens cover base from the photographing lens side.

As described above, since the conventional lens cover unit is disposed in the order of the lens cover, the lens cover, and the lens cover base in this order from the photographing lens side, the lens cover has a thickness corresponding to the thickness of the lens cover ring. It is located far from the front lens, and when considering the light beam obliquely incident on the front lens, the aperture had to be large, as a result, the size of the lens cover itself became large, and the lens barrel was also thick. . In addition, the lens cover unit needs to have a certain thickness by stacking the lens cover, the lens cover, and the lens cover base.

In view of such a problem, it is an object of the present invention to provide a camera having a lens cover unit having a small outer diameter, a thin lens barrel, and a small thickness.

The object is to provide a lens cover that opens and closes by rotating the lens cover in front of the photographing lens from the photographing lens side, a lens cover base that pivotally supports the lens cover, and opens and closes the lens cover by rotating. The problem is solved by a camera having a lens covering and a decorative frame that carries out the exterior and holds the lens covering.

According to the camera of the first aspect, since the lens cover is disposed immediately before the front lens, it is sufficient to open the lens cover with a minimum size in consideration of light beams obliquely incident on the front lens. The size of the cover itself is reduced, and the outer diameter of the lens barrel can be formed to a minimum thickness.

According to the camera of the second aspect, the lens cover ring is arranged in the circular groove provided in the lens cover base, so that a thin lens cover unit can be realized.

First, a zoom lens barrel of a camera having a lens cover according to the present invention will be described with reference to FIGS. FIG. 1 is a longitudinal sectional view of the zoom lens barrel. The upper half of the optical axis shows the state when the short focus is set, and the lower half of the optical axis shows the state when the long focus is set. It is painted. FIG. 2 is an exploded perspective view showing the zoom lens barrel.

In both figures, reference numeral 1 denotes a fixed body, which carries all of the following members and is fixed to a camera body (not shown). The fixed cylinder 1 has a female helicoid 1a screwed on the inner periphery thereof, and two guide grooves (not shown) for a rectilinear guide, which will be described later, are provided substantially symmetrically about the optical axis O and parallel to the optical axis O. I have. Reference numeral 2 denotes a cam cylinder, on the outer circumference of which a male helicoid 2a screwed with the female helicoid 1a and a large gear 2b are integrally formed, and on the inner circumference thereof, a female helicoid 2c and a cam groove 2d are formed. Further, since the diameter of the addendum circle of the large gear 2b is formed smaller than the root diameter of the male helicoid 2a, it does not come into contact with the peak of the female helicoid 1a of the fixed barrel 1. A decorative frame 3 covers the female helicoid 2c and the like of the cam cylinder 2.

4 is a second lens group holding frame holds the second lens group L _F2 in the front lens group of the inner zoom in peripheral lens, further referred to as second lens group holding member according to claim from the rear The second lens group L _F2 is pressed by a lens holding plate 5 made of a thin plate. A male helicoid 4a is screwed around the outer periphery, and the male helicoid 4a is screwed with the female helicoid 2c of the cam cylinder 2.

{Circle around (2)} The front outer periphery 4c of the second lens group holding frame 4 is exposed as it is to form one of the exterior members.

A first lens group holding frame 6 for holding the first lens group L _F1 in the front lens group is disposed in front of the second lens group holding frame 4, and the first lens group holding frame 6 is a shutter that also serves as an aperture. It is fixed to the second lens group holding frame 4 with the blade 7 interposed therebetween. Further, circuits and actuators for driving the shutter blades 7 are respectively provided at the positions of the front portion 8 of the first lens group holding frame 6.

Reference numeral 11 denotes a rear lens group holding frame for holding the rear lens group L _R , and convex portions 11 a provided in three places on the outer periphery of the rear lens group holding frame 11 and parallel to the optical axis, and a second lens group holding frame 4. And three concave portions 4b parallel to the optical axis, which are provided at three locations on the inner rear side. Therefore, the rear lens group holding frame 11 is held by the second lens group holding frame 4 while maintaining the same optical axis, and the rear lens group holding frame 11 slides in the optical axis direction with respect to the second lens group holding frame 4. It can move, but cannot rotate about the optical axis. Also, three cam pins 12 are provided upright on the convex portion 11a of the rear lens holding frame 11, and are engaged with a cam groove 2d provided together with the female helicoid 2c on the inner periphery of the cam cylinder 2. .

The linear guide plate 13 bent in an L-shape by a metal plate is rotatably attached to the rear portion 2e of the cam cylinder 2 around the optical axis O by a member (not shown). The rectilinear guide plate 13 has two rectilinear guide portions 13a parallel to the optical axis O. The rectilinear guide portions 13a pass outside the outer periphery of the rear lens group holding frame 11 and are inside the second lens group holding frame 4. It is engaged with the long groove and the through hole provided on the circumference. On the other hand, the rectilinear guide plate 13 has two protrusions 13b orthogonal to the optical axis O, and engages with two guide grooves, not shown, provided on the fixed body 1 and parallel to the optical axis O. are doing.

Therefore, when the cam barrel 2 moves forward and backward while rotating, the straight guide plate 13 is prevented from rotating by the projection 13b, and performs only the straight movement together with the cam barrel 2. For this reason, the rotation of the second lens group holding frame 4 is prevented by the rectilinear guide section 13a, and only the rectilinear movement is performed. In addition, since the rear lens group holding frame 11 is slidably engaged with the second lens group holding frame 4 only in a direction parallel to the optical axis, the rear lens group holding frame 11 also only moves straight.

As described above, the shutter driving member is located in front of the second lens group holding frame 4 and a sufficient space is provided behind the second lens group holding frame. The engagement length of the group holding frame 11 with the convex portion 11a can be sufficiently set, and the optical axis of the first lens group L _{F1, that} is, the optical axis of the front lens group and the rear lens group L surely coincides with each other.

In addition, between the cam pin 12 erected on the rear lens holding frame 11 and the cam groove 2 d of the cam cylinder 2, play in a direction parallel to the optical axis occurs due to processing accuracy. In order to absorb this play, protrusions 5a are provided at three places on the outer periphery of the lens holding plate 5 holding the second lens group L _F2 , and between the protrusions 11b similarly provided on the rear group lens holding frame 11. The tension spring 14 is attached. As a result, the cam pin 13 is always urged forward in the cam groove 2d and comes into contact with only the front side surface of the cam groove 2d, so that the play of the cam groove 2d becomes irrelevant.

Since the shutter driving member is located in front of the second lens group holding frame 4 as described above, the extension spring 14 can be attached in this manner.

に Also, contrary to the above, a cam groove may be provided in the rear lens holding frame 11 and a cam pin may be provided in the cam barrel 2.

Next, the lens cover will be described with reference to FIG. 3 in addition to FIGS.

1 and 2, the members forming the lens cover include a lens cover 21 composed of two members in front of the first lens unit L _F1 (subject side) and in order from the first lens unit L _F1 side. A lens cover base 23 that holds a support shaft 22 that rotatably supports the cover 21 through a shaft hole 21a, a lens cover ring 24 that is rotated by a member described below to open the lens cover 21 in a closed state, A decorative frame 25 which is an exterior member obtained by covering the above member and drawing a thin plate is arranged.

Further, by inserting the lens cover ring 24 into a groove provided circumferentially in the lens cover base 23, positioning around the optical axis O is performed, and with respect to the thickness direction of the lens cover ring 24, Positioning is performed by the bottom face of the groove 23 and the decorative frame 25.

In FIG. 2, an operating pin 24 a is provided on the rear of the lens cover ring 24, and engages with the long hole 21 b of the lens cover 21 through the long hole 23 a of the lens cover base 23. A spring (not shown) is applied to the lens cover ring 21 to urge the lens cover ring 24 clockwise. Therefore, the lens cover ring 24 when not driven by a member which will be described later, the lens cover 21 becomes closed state by rotating in the clockwise direction about the shaft hole 21a, to cover and protect the front of the first lens group L _F1.

Next, the opening and closing mechanism of the lens cover will be described with reference to FIGS. FIG. 3 is a plan view of the lens cover driving mechanism, FIG. 3A is a view showing a state where the lens cover is closed, and FIG. 3B is a view showing a state where the lens cover is opened.

In both figures, reference numeral 31 denotes a lens cover operating member, which is attached to the camera body or the fixed body 1 (not shown) and is slidable in the left-right direction, and is urged in the negative direction by a tension spring 32.

Reference numeral 33 denotes a third lens cover driving member, which is similarly mounted on the camera body or the fixed body 1 and is slidable in the left-right direction, urged in one direction by a tension spring 34, and bent in an L-shape. The engaged first end 33a is engaged with the lens cover operating member 31. A second lens cover driving member 35 engages with a long groove (not shown) parallel to the optical axis provided on the inner periphery of the second lens group holding frame 4 and is slidable in the optical axis direction. When the cover is closed, the rear end 35a is in contact with the L-shaped second end 33b of the third lens cover driving member 33 as shown in FIG. Reference numeral 36 denotes a first lens cover driving member, which is formed in a crank shape and is urged counterclockwise by a torsion coil spring 38 about a support shaft 37 provided on the first lens group holding frame 6, and is provided at one end. The provided forked portion 36a is engaged with the engaging pin 35b erected on the second lens cover driving member 35, and the side surface of the other end portion 36b is provided on the side of the engaging portion 24b bent rearward of the lens cover ring 24. It can be engaged with the side surface.

Only when the first lens group holding frame 6 is fixed to the second lens group holding frame 4, the forked portion 36a of the first lens cover driving member 36 and the engagement pin 35b of the second lens cover driving member 35 are engaged. Combine.

In the above configuration, when the zoom lens barrel is retracted, it is in a state as shown in FIG. 3A, and the side surface of the other end 36b of the first lens cover driving member 36 is a lens covering. 24 are separated from the side surface of the engaging portion 24b. Therefore, as described above, the lens cover ring 24 is rotated clockwise to close the lens cover 21.

In this state, when the lens cover operation member 31 is slid leftward as shown in FIG. 3B against the tension spring 32, the third lens cover driving member 33 is also moved by the tension spring 34 by the first end 33a. Slide to the left against Then, the contact between the second end 33b of the third lens cover driving member 33 and the rear end 35a of the second lens cover driving member 35 is released. As a result, the second lens cover driving member 35 slides rearward by the urging force of the torsion coil spring 38. Then, the second end 33 b of the third lens cover driving member 33 comes into contact with the notch 35 c of the second lens cover driving member 35.

In this state, the right side of the second end 33b of the third lens cover driving member 33 contacts the left side of the rear end 35a of the second lens cover driving member 35. The spring cannot return to the right due to the urging force of the extension spring. However, only the lens cover operation member 31 can be independently returned to the original position by the tension spring 32.

Further, in this state, the first lens cover driving member 36 rotates counterclockwise, but the biasing force of the torsion coil spring 38 is greater than the biasing force of the biasing member that rotates the lens cover ring 24 clockwise. Because it is stronger. As a result, the side surface of the other end portion 36b of the first lens cover driving member 36 presses the side surface of the engaging portion 24b of the lens cover ring 24, and rotates the lens cover ring 24 counterclockwise in FIG. Therefore, the lens cover 21 rotates counterclockwise about the shaft hole 21a by the counterclockwise rotation of the operating pin 24a of the lens cover ring 24, and the lens cover 21 is opened.

When the lens cover operation member 31 is operated as described above, a switch (not shown) is turned on, and the zoom lens barrel is extended to a wide-angle position. It is sent out to the state. At this time, the second lens cover driving member 35 is located at a position farther from the third lens cover driving member 33, but is provided on the second lens group holding frame 4 even when biased rearward by the torsion coil spring 38. The stopper does not move backward beyond the specified position due to the stopper. Further, the lens cover 21 maintains the open state. As a result, the contact between the right side surface of the second end 33b of the first lens cover driving member 33 and the left side surface of the rear end 35a of the second lens cover driving member 35 is released. The driving member 33 returns rightward by the urging force of the tension spring 34.

When the lens cover operation member 31 is operated again after the photographing is completed, a switch (not shown) is turned on, and the zoom lens barrel is retracted to the retracted position. With this operation, the second lens cover driving member 35 also retreats, but since the third lens cover driving member 33 has returned to its original position, the rear end of the second lens cover driving member 35 has the third end 35a. Even if the second end portion 33b of the lens cover driving member 33 abuts and the first lens group holding frame 6 moves backward, the second lens cover driving member 35 cannot move backward. As a result, as shown in FIG. 3A, the first lens cover driving member 36 rotates, and the side surface of the other end portion 36b is separated from the side surface of the engagement portion 24b of the lens cover ring 24. The lens cover 21 is rotated by a spring (not shown) to close the lens cover 21.

The operation of the zoom lens barrel having the above configuration will be described below.

When the lens cover operation member 31 is operated as described above, a switch (not shown) is turned on, and the lens barrel drive motor 41 shown in FIG. 4 is driven to rotate. FIG. 4 is a perspective view of a lens barrel drive motor for driving the small gear 15 shown in FIG. 2, a reduction gear, and the like, as viewed from the other side of FIG. When the lens barrel drive motor 41 rotates, the rotation of the pinion 43 attached to the motor shaft 42 is transmitted to the long gear 49 in the optical axis direction via the reduction gears 44, 45, 46, 48, and is transmitted to the straight guide plate 13. The small gear 15 rotatably mounted is rotated.

(4) A propeller 51 having a plurality of blades is attached to the motor shaft 42, and a pulse signal is output by a photo interrupter 52. A propeller 53 having one blade is attached to a gear shaft 47 of the reduction gear 46, and a pulse signal is output by a photo interrupter 54. The operation of these pulse signals will be described later.

Since the small gear 15 meshes with the large gear 2b of the cam cylinder 2, the cam cylinder 2 is extended from the fixed barrel 1 according to the lead of the male helicoid 2a while rotating. When the cam cylinder 2 rotates, the rotation is transmitted to the male helicoid 4a of the second lens group holding frame 4 by the female helicoid 2c, but the rotation of the second lens group holding frame 4 is prevented by the rectilinear guide plate 13. Therefore, it is fed straight out according to the lead of the male helicoid 4a.

The second lens group L _F2 is held by a second lens group holding frame 4, the first lens group L _F1 is held by a first lens group holding frame 6, and the first lens group holding frame 6 is Are fixed to the second lens group holding frame 4 with the first lens group _LF1 and the second lens group _LF2 , which are front lens groups, with two helicoids maintained at a constant lens interval. It will be paid out according to the lead.

On the other hand, the rotation of the cam groove 2d of the cam barrel 2 causes the cam pin 12 to move in the optical axis direction and the rear lens group holding frame 11 to be prevented from rotating by the second lens group holding frame 4. The frame 11 is fed straight out according to the shape of the cam in the cam groove 2d. Therefore, the rear lens group _LR is straightly extended according to the lead of the male helicoid 2a of the cam cylinder 2 and the cam shape.

Next, zooming and focusing in the present zoom lens barrel will be described. This zoom lens barrel is a so-called step zoom system in which the space between the wide-angle end and the telephoto end is divided into a predetermined number of steps, that is, steps, and zooming and focusing can be performed by the same mechanism. Thus, a zoom lens barrel having a simple configuration can be realized.

Explaining with reference to the step zoom diagram of FIG. 5, the horizontal axis indicates a change in the focal length, and is divided into six steps from the wide-angle end W to the telephoto end T. The vertical axis indicates the amount of movement of the front lens group and the rear lens group of the zoom lens in the optical axis direction. As described above, the front group lens moves linearly because it moves only by the helicoid, but the rear group lens moves by the cam, so that an arbitrary movement diagram can be provided. For example, when focusing is performed from the state <1> at infinity あ る which is the initial position at the wide angle end W, the lens is moved to the state <2> at the close distance N. The state of <2> corresponds to the closest distance N of the initial position at the focal length M ₁ of the wide angle to the second, when performing focusing in focal length M ₁ of the wide-angle to the second, <2> in the close range N The lens is moved from the state to the state <3> at infinity ∞. The second state of <3> at infinity に お け る at the wide-angle focal length M ₁ corresponds to the third position at infinity の of the initial position at the wide-angle focal length M ₂ . As described above, in the step zoom method, since focusing is performed while performing zooming, that is, while changing the focal length, zooming and focusing can be performed by the same mechanism.

構成 The structure of this step zoom will be described in more detail with reference to FIGS. FIG. 6 is a timing chart of the movement of the lens barrel from the retracted position to the photographing area, and FIG. 7 is a block diagram of control means for controlling the advance / retreat of the lens barrel.

In FIG. 6, the retracted position on the horizontal axis is the position where the lens barrel is most retracted to the film side, and the non-photographing area is an area where the lens barrel is extended from the retracted position but cannot be photographed. Is an area where the focal length can be changed in six steps (small area in the claims) between the wide-angle end W, which is the widest angle, and the telephoto end T, which is the longest, as described above. The zoom position switch on the vertical axis corresponds to the propeller 53 and the photo interrupter 54 shown in FIG. 4, and outputs a pulse signal (referred to as LDP2) for determining an initial position of each step in a photographing area at a constant interval. However, when the reduction gear 46 rotates as shown in FIG. 4, the pulse signal LDP2 is generated even in the non-photographing area. Although not shown, the retractable switch is a switch that is switched from on to off in a non-photographing area as the lens barrel moves.

When the power switch for starting the position control of the lens barrel is turned on when the lens barrel is in the retracted position, the control circuit shown in FIG. 7 detects the ON state of the retracted switch, and the lens barrel drive motor 41 rotates. The lens barrel is extended. At this time, only the number of pulse signals LDP2 of the zoom switch is counted irrespective of ON / OFF of the retracting switch. In FIG. 6, when the third pulse signal LDP2 is output, the lens barrel is output. Stops. This position is the initial position of the wide-angle end W which is the first step in the photographing area. Focal length if caused to operate the zoom switch in this state is shifted to M ₁ through T, you can choose any focal length. When focusing is performed, the distance information from the distance measuring circuit is compared with the number of continuous pulse signals (referred to as LDP1) having a fine pitch outputted by the propeller 51 and the photo interrupter 52 shown in FIG. Stop the lens barrel at the position.

When the power switch is turned off when the lens barrel is in the photographing area, the lens barrel is retracted after detecting the OFF state of the retractable switch regardless of the pulse signal LDP2 of the zoom position switch, and the retractable switch is turned on. Then, when the number of predetermined pulse signals LDP1 is counted, it is determined that the lens barrel has retracted to the retracted position, and the lens barrel drive motor 41 is stopped.

As described above, the control circuit shown in FIG. 7 controls the lens barrel drive motor M based on the distance information from the power switch, the zoom switch, the distance measuring circuit, the pulse signals LDP1 and LDP2, and the retract switch signal.

FIG. 2 is a longitudinal sectional view of a zoom lens barrel. FIG. 2 is an exploded perspective view showing a zoom lens barrel. It is a top view of a lens cover drive mechanism. FIG. 3 is a perspective view of a lens barrel drive motor and the like. It is a step zoom diagram. 6 is a timing chart of lens barrel movement. It is a block diagram of the control means which controls the advance / retreat of a lens barrel.

Explanation of reference numerals

L _F1 first lens group L _F2 second lens group L _R rear group lens 1 fixed body 2 cam cylinder 4 second lens group holding frame 5 lens holding plate 6 first lens group holding frame 7 shutter blade 11 rear group lens holding frame DESCRIPTION OF SYMBOLS 13 Straight guide plate 14 Extension spring 21 Lens cover 23 Lens cover base 24 Lens covering 25 Decorative frame 33 Third lens cover driving member 35 Second lens cover driving member 36 First lens cover driving member 51, 53 Propeller 52, 54 Photo Interrupter

Claims (2)

In front of the taking lens, in order from the taking lens side, a lens cover that opens and closes by turning, a lens cover base that pivotally supports the lens cover, a lens cover ring that turns and opens and closes the lens cover, And a camera which is provided with an exterior frame and a decorative frame for holding the lens covering. The camera according to claim 1, wherein the lens cover ring is arranged in a circular groove provided in the lens cover base.

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