JPH0785157B2 - Lens barrel for video camera - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to a lens barrel for a video camera, more specifically, a photographic optical system and a finder optical system, which are completely separated from each other while switching between tele and wide. The present invention relates to a lens barrel for a video camera in which an optical system is interlocked with and switched.

[Prior Art] As is well known, in a video camera, the relationship between the photographing optical system and the viewfinder optical system is CRT in the case of the zoom optical system.
An EVF (Electronic Viewfinder) type lens system that uses a (cold cathode ray tube), etc., that has only a shooting system, a system in which a prism is placed in the rear position of the zoom lens to divide the shooting optical path and the finder optical path, and In the case of a focus lens, in addition to the above, the taking lens system and the finder lens system can be roughly classified into three types.

However, it has not been known until now that the photographic lens system and the finder lens system are independent of each other, but both optical systems are simultaneously operated for zooming.

In addition, various types of compact cameras that perform still photography are known, such as a tele (telephoto) and a wide (wide-angle) focal length switching method. These are a taking lens and a finder lens, and an interlocking member such as a lever. When the magnification is changed, a means for moving the lens group for magnification change in and out on the optical axis is used.

[Problems to be Solved by the Invention] However, when considering a bifocal camera similar to the tele / wide switching in the still camera in the video camera, the type in which the zoom lens group is put in and out is Requires a large space, and linking the photographic lens and the finder lens in different optical paths by levers etc. increases the space and complicates the mechanism, which is a great obstacle to the reduction in size and weight of the entire video camera. .

Therefore, the object of the present invention is to eliminate the above-mentioned adverse effects, while the photographing optical system and the finder optical system are completely separate optical paths, and when switching between tele and wide, only one cam barrel is operated to rotate both optical systems. There is provided a lens barrel for a video camera, which can be moved at the same time to switch between tele and wide.

[Means for Solving the Problems] In order to solve the above problems, according to the present invention, a part of the photographing optical system is moved from one end position to the other end position in the optical axis direction, and a two focal length is set. The photographic lens optical system for switching the optical axis and the photographic lens optical system are arranged so that their optical axes are parallel to each other, and part of the optical system is moved from one end position to the other end position in the optical axis direction. A finder optical system for moving the magnification to switch the magnification and an interlocking pin fixed to the moving lens frame of the taking lens optical system, which is rotatably disposed on the outer circumference of the taking lens optical system. A cam cylinder having a first cam groove hole into which the outer periphery of the interlocking pin fixed to the movable lens frame of the finder optical system is fitted; ing.

[Operation] One cam barrel is rotated, and one interlocking pin is driven by the first cam groove hole to move part of the lenses in the photographing optical system from one end position to the other end position. The focal length is switched by moving it in the optical axis direction, and the other interlocking pin is driven by the second cam groove hole to move some lenses in the finder optical system from one end position to the other end position. It is moved in the direction of the optical axis to switch the magnification to switch between tele and wide.

[Examples] Hereinafter, the present invention will be described with reference to illustrated examples.

FIG. 1 is a diagram showing an internal structure of a lens barrel for a video camera showing an embodiment of the present invention, which is I- of FIG.
It is sectional drawing which follows the I line. Further, FIG. 3 shows III in FIG.
It is a sectional view taken along the line III. The left side in FIG. 1 is the subject side, and the right side is the photographer side.

As shown in FIG. 1, the taking lens optical system comprises a fixed lens group including a first lens group including lenses L11 and L12 forming a focus group and a second lens group including lens L21 forming a variable power group. It is formed of a three-lens type including a third lens group consisting of the lenses L31, L32, and L33, and the finder lens optical system is a lens FL1 that forms a fixed lens group.
1, FL12, FL13 and FL21, FL41, lenses FL31, FL32 forming a variable power lens group, and lenses FL51, FL52 forming a diopter-adjustable eyepiece lens group.

The entire finder lens optical system is housed in a finder cylinder 4 having a small diameter and a long diameter. The cylinder 4 is divided into upper and lower halves as shown in FIG. Part of the cover cylinder 4A and the lower half of the support cylinder 4B, the lower half of the support cylinder 4B in the lower part near the front,
A holding cylinder 3 for accommodating the taking lens optical system is integrally formed. An inward flange portion 3a for mounting a fixed cylinder is provided in the inside of the holding cylinder 3 toward the front portion thereof, and a plurality of screw insertion holes are formed at equal intervals in the flange portion 3a. .

Then, as shown in FIG. 1, a fixed cylinder 1 in which a cam cylinder 2 (see FIG. 7) is rotatably fitted to the outer peripheral surface is fitted and fixed in the holding cylinder 3. ing. That is, as shown in FIG. 5, the fixed cylinder 1 has an outward flange portion 1b provided near the front portion of the outer peripheral surface thereof and has a flange portion 3a of the holding cylinder 3.
Then, the fixing screw 37 (see FIG. 1) which has been overlapped with the flange 3a is screwed into the holding cylinder 3 to be integrally attached. The horizontal notch 1c of the outward flange 1b is a rotational direction position restricting portion when the fixed cylinder 1 is attached to the holding cylinder 3.

Returning to FIG. 1, a helicoid screw 1a is engraved on the front inner peripheral surface of the fixed cylinder 1 fixed to the holding cylinder 3 in this manner, and the helicoid screw 1a is formed on the outer peripheral surface of the focus frame 6. The helicoid screw 6a engraved on is screwed. The focus frame 6 is a lens holding ring screwed in from the front.
The first lens unit L11, L12 of the taking lens optical system attached by 19 is held, and the projection 6b for rotation is integrally provided. Lens that is the second lens group of the photographing lens optical system
The L21 is fixed to the variator frame 7 by adhesion, and the variator frame 7 has a holding portion 7a and a fitting portion 7b which project in the radial direction as shown in FIGS. A pipe 16 parallel to the optical axis direction is embedded in the holding portion 7a, and a pin 32 protruding in the radial direction is planted.
A roller 33 is integrally attached to 32. Here, FIG. 4 shows the internal structure in a horizontal cross section of the fixed frame 1.

As shown in FIG. 4, the pipe 16 is slidably fitted to the guide shaft 14 arranged parallel to the optical axis, and the fitting portion 7b is also arranged parallel to the optical axis. The guide shaft 15 is slidably fitted. Both shafts 14,1 above
5 has one end fixed to the shaft support ring 17 and the other end fixed to the fixed cylinder 1 to the rear flange 1d so as to be laterally mounted on both sides of the photographing optical system. The shaft support ring 17 is fitted into the restriction hole of the fixed barrel 1, is attached to the fixed barrel 1 by a C ring 18, and is fixed to the fixed barrel 1 so as not to rotate by a positioning portion (not shown). Also,
The pin 32 and the roller 33 supported by the pin 32 penetrate the straight groove 1e formed in the fixed barrel 1 in the optical axis direction, and the cam groove 2a (7th, 8th holes) formed in the cam barrel 2 (See the figure).

Returning to FIG. 1 again, the lens L31 constituting the third lens group in the optical system for taking lenses is fixed to the one third group support frame 8 by the spring ring 20, and the lenses L32 and L33 are the other three groups. It is fixed to the support frame 9 via a spacer 22 by a spring ring 23. Further, between the third group support frame 8 on the one hand and the third group support frame 9 on the other hand, as shown in FIG.
21 and auto iris 5 are arranged, and both frames 8 and 9 are screwed 3
Rubber ring 2 by tightening with 8 (see Fig. 1)
The auto iris 5 is fixed via 1. That is, both frames
8,9 and Auto Iris 5 are integrated. The opening of the auto iris 5 is automatically and properly controlled by the iris motor 5a. Here, FIG. 9 is drawn upside down from FIG. 1 to show the screw hole 9a. Here, the horizontal cutout portion 8a of the one third group support frame 8 and the horizontal cutout portion 9d of the other third group support frame 9 respectively indicate the mounting escape portions of the auto iris 5, and similarly the cutouts 8b, 8c and 9b, 9c are It is an escape portion for the guide shafts 14 and 15 shown in FIG.

Further, the rear portion of the other third group support frame 9 is fitted in the rear opening portion of the fixed barrel 1 as shown in FIG. 1, and this fitting portion is fitted in the rear opening portion as shown in FIGS. A screw hole 9a is provided. As shown in FIG. 4, an FC adjusting screw 36 is fastened to the screw hole 9a through an elongated hole 1f formed in the fixed barrel 1 in the optical axis direction. As a result, the third group support frames 8 and 9 can be slightly moved, and FC adjustment is performed during assembly.

Then, at the rear end of the fixed barrel 1, as shown in FIG.
The element mounting frame 10 is fixed by 40, and a filter 11 such as a crystal filter, a pressing rubber 24, and a CCD 12 which is an imaging element are pressed and fixed to the mounting frame 10 by a CCD pressing member 13.
The CCD pressing member 13 is attached to the element mounting frame 1 by a screw (not shown).
It is fixed at 0.

On the other hand, the cam barrel 2 is rotatably fitted on the outer periphery of the fixed barrel 1. The movement of the cam barrel 2 in the direction of the optical axis is restricted by the outward flange portion 1b at the front portion of the fixed barrel 1 and the cam retainer 25 fixed to the flange 1d of the fixed barrel 1 with screws 39. As shown in FIGS. 7 and 8, the cam barrel 2 is provided with a photographic lens cam groove hole 2a and a finder cam groove hole 2b, and the variator frame 7 is provided in the photographic lens cam groove hole 2a. The roller 33 that is planted in is inserted. The cam barrel 2 is provided with a screw hole 2c for fixing the operation pin 43 (see FIG. 1) and a cutout portion 2d which is a relief portion of the auto iris 5. Further, linear portions 2e, 2f, 2g, 2h having no movement amount in the optical axis direction are provided at both ends of the cam groove holes 2a, 2b, respectively. Further, the operation pin 43 which is planted in the screw hole 2c and extends in the radial direction.
As shown in Figs. 1 and 6, the holder cylinder 3 penetrates through a partial arc-shaped hole 3b formed in a direction perpendicular to the optical axis and extends outward.

Next, a description will be given of an arrangement mode of each lens constituting the finder optical system. As shown in FIG.
FL11, FL12, FL13 are held by being pressed by the elastic claw member 26a via the first spacer 29 and the second spacer 30 on the support frame 26. This fixed lens FL11, F
Support frame 26 holding L12, FL13 and fixed lenses FL21, FL4
1, the field frame 31, and the flare prevention fixed diaphragm 42 are directly held in respective positioning groove portions provided on the inner peripheral surfaces of the cover cylinder 4A and the support cylinder 4B.

The lenses FL31 and FL32 constituting the variable power lens group are formed by cemented lenses, and are composed of a relatively long tubular body having a small diameter and tightly fitted in the tubular body 4 slidably in the optical axis direction. It is fixed to the frame 27 by a caulking portion 27a. The moving frame 27 has a screw hole 27b near the front thereof.
As shown in FIGS. 1 and 3, a pin 34 having a roller 35 forming a cam follower fitted therein is screwed into the screw hole 27b so as to project in the radial direction. And this pin 34, roller 35
Is a rectilinear groove 3c formed in the support cylinder 4B in the optical axis direction, and a finder cam groove hole 2b (first groove) formed in the cam cylinder 2.
(See Figures 7 and 8).

Here, the photographing lens cam groove hole 2a constitutes the first cam groove hole in the present invention, and the finder cam groove hole 2b.
Constitutes a second cam slot.

On the other hand, as shown in FIG. 1, the lenses FL51 and FL52 forming the eyepiece lens group are formed by cemented lenses, and are slid in the optical axis direction on the inner peripheral surface of the cylindrical body 4 near the end on the photographer side. An elastic claw member 28a holds the diopter frame 28 that is movably fitted. The diopter frame 28 is integrally formed with diopter adjusting pins 28b, 28b projecting outward at its symmetrical position, and the pins 28b, 28b are provided with the cover as shown in FIGS. Cylinder
4A and cam barrel hole 4 for adjusting diopter in support tube 4B
It is inserted in a and 4a.

In this way, the entire viewfinder lens optical system is a cover cylinder.
It is held by 4A and the support tube 4B. Further, as shown in FIGS. 3 and 6, the cover cylinder 4A and the support cylinder 4B that sandwich the finder lens system are integrated with the support cylinder 4B by fixing the cover cylinder 4A to the support cylinder 4B at a plurality of positions with screws 41. The cover body 4A and the support cylinder 4B are integrated with each other by forming the concave-convex portions 3e, 3d, 3f, 3g, 4c, and 4b on both ends of the cover cylinder 4A and the support cylinder 4B. Has become.

Further, as shown in FIG. 1, when the fixed cylinder 1 and the holding cylinder 3 are fixed, the pin 34 and the roller 35 planted in the screw hole 27b of the moving frame 27 support the movement in the rotational direction in the supporting cylinder 4B. It is regulated by a rectilinear groove 3c formed in the optical axis and parallel to the optical axis, and its movement in the optical axis direction is regulated by a first cam groove hole 2b provided in the cam barrel 2. Further, the operation pin 43 fixedly implanted in the cam cylinder 2 penetrates an arcuate hole 3b provided in the holding cylinder 3 and can be linked with an external operation member (not shown).

The taking lens optical system and the finder lens optical system thus configured are fixed to a video camera main body (not shown), and the CCD 12, the auto iris 5 and the like are connected to the camera main body side by appropriate means.

Next, the switching operation from the lens wide to the tele in the lens barrel of the above embodiment will be described. FIG. 1 shows a state in which the focal length is wide (wide angle) and the photographing distance is long.

When focus adjustment is performed in this state, the rotation protrusion 6b integral with the forky frame 6 is moved in the rotation direction by an interlocking member (not shown). Focus frame 6 is a helicoid screw 6
Since the focus frame 6 is held by the fixed barrel 1 by a and 1a, the focus frame 6 moves toward the front in the optical axis direction with respect to the fixed barrel 1 by the rotation, whereby the lenses L11 and L12 of the first lens group L1 and L12.
To move the lens to focus the taking lens. Focusing in the present embodiment is so-called zone focus in which stop positions are determined at several places.

On the other hand, in the finder optical system, the diopter adjustment pin 28b integrated with the diopter frame 28 is rotated by an operation member (not shown) and moved in the diopter adjusting cam groove hole 4a to adjust the diopter. At this time, the viewfinder optical system does not interlock with the focusing operation of the taking lens optical system, and an in-focus image can always be visually recognized in the viewfinder.

Further, during photographing, the iris motor 5a is sequentially operated according to the brightness of the subject, and the auto iris 5 always supplies the CCD 12 with an appropriate amount of light.

Next, the operation when the focal length is switched from wide to tele (telephoto) will be described.

When switching from wide to tele is performed by a switching member (not shown) on the camera side, the operation pin 43 moves from the WIDE position to the TELE position in FIG. As a result, the cam cylinder 2 in which the operation pin 43 is fixedly fixed also rotates in the same direction.

A roller that controls the magnification of the shooting and viewfinder lenses
When the lens 33 and the roller 35 are wide, the WID of the cam groove hole 2a for the photographing lens and the cam groove hole 2b for the finder in FIG.
It is located at E end 2e and 2g.

Therefore, when the cam barrel 2 rotates as described above, the roller 3
3, Roller 35 guide shaft 15 in the direction of rotation with respect to the optical axis
Since it is restricted by the straight groove 3c, it moves along the cam groove holes 2a, 2b, respectively, and stops at the TELE ends 2f, 2h of the cam groove holes 2a, 2b corresponding to the tele positions. The operating state at this time is the tele-infinity state shown in FIG.

Incidentally, the focusing operation in the tele is the same as that in the wide mode.

Further, the cam lens hole (first cam groove hole) 2a and the finder cam groove hole (second cam groove hole) 2b which are respectively formed in the cam barrel 2 in the above embodiment are the tenth. As shown in the drawing, one end of each of the cam groove holes 102a and 102b may be connected to be common. That is, the TELE end 10 on the side opposite to the WIDE end 102c of the photographing lens cam groove hole 102a formed in the cam barrel 102
2d and the WIDE end 102d on the opposite side of the TELE end 102e of the viewfinder cam slot 102b are commonly connected. That is, in the above-mentioned embodiment, both pins of the pin 34 implanted in the moving frame 27 in the optical axis direction at the time of TELE and the pins 32 implanted in the variator frame 7 in the optical axis direction at the time of WIDE are aligned so that both pins are aligned. It is configured to set 32 and 34 positions.

Therefore, in the WIDE state, the viewfinder pin 34 and roller 3
5 is located at WIDE end 102d, pin 32 on the shooting lens side, roller
33 is located at the WIDE end 102c. When WIDE is switched to TELE, the cam barrel 102 is rotated to the right in FIG. 10, and the pins 32 and 34 and the rollers 33 and 35 are moved to WIDE.
After passing through each horizontal part of the ends 102c, 102d, the cam groove hole 102a,
It moves along 102b, reaches the TELE ends 102d and 102e, and switches to the TELE state.

In this way, if both ends of both cam groove holes 102a and 102b are connected and commonly used, both optical systems can be moved by one cam groove hole, and the cost and the space of the cam portion can be reduced. be able to.

[Effects of the Invention] As described above, according to the present invention, in a lens barrel that simultaneously switches the photographing optical system and the finder optical system by a tele / wide switching operation, one lens that is rotatably fitted to the outer periphery of the photographing optical system is used. A cam cylinder is provided, and a cam groove hole for a photographing lens and a cam groove hole for a finder lens are formed on the cam cylinder.
Since the photographing optical system variable power lens restricting pin is fitted into the cam barrel and the finder optical system variable lens restricting pin is fitted from the outer side of the cam barrel into the respective cam groove holes, one cam barrel is used. Just rotate the
The variable power lens of the two lens systems arranged parallel to the optical axis can be switched and moved without using any interlocking member such as a lever.

Further, since the linear portion having no movement amount in the optical axis direction is provided at the end of the cam groove hole, it is not necessary to make the stop position accuracy of the cam barrel in the rotation direction severe.

Therefore, according to the present invention, it is possible to provide a lens barrel for a video camera, which can easily switch between tele and wide, and can promote reduction in size and weight of the entire video camera.

[Brief description of drawings]

1 is a lens barrel for a video camera showing an embodiment of the present invention, which is a sectional view taken along the line I-I in FIG. 3, and FIG. 2 is the lens barrel of FIG. FIG. 3 is a sectional view showing a state where the variable power lens is moved to the telephoto infinity position in FIG. 3, FIG. 3 is a sectional view taken along the line III-III in FIG. 1, and FIG. 4 supports the variable power lens. FIG. 5 is a cross-sectional view showing the moving mechanism of the variator frame, FIG. 5 is a perspective view showing only the fixed barrel from FIG. 1, and FIG. 6 is a viewfinder barrel and lens holding from FIG. FIG. 7 is an exploded perspective view showing a cylinder taken out, FIG. 7 is a perspective view showing only the cam cylinder taken out of FIG. 1, FIG. 8 is a developed view of a main part of the cam cylinder, and FIG. FIG. 10 is an exploded perspective view showing only the third group support frame from FIG. 1, and FIG. 10 shows a cam groove hole formed in the cam barrel. It is a main part development view of the cam cylinder showing a Katachirei. L21: Variator lens (part of projection optical system) FL31, FL32: Variable-magnification lens (part of viewfinder optical system) 1 ... Fixed barrel 2 ... Cam barrel 2a, 102a ... Cam slot for shooting lens (First cam groove hole) 2b, 102b ...... Cam groove hole for finder lens (second cam groove hole) 2e, 2f, 2g, 2h, 102c, 102d, 102e ...... Straight section 7 ...... Variator frame ( Moving lens frame) 27 …… Moving frame (moving lens frame) 32,34 …… Interlocking pin 33,35 …… Roller

Claims (3)

[Claims] 1. A photographic lens optical system for switching between two focal lengths by moving a part of the photographic optical system from one end position to the other end position in the optical axis direction. A finder optical system for arranging a part of the optical system in the optical axis direction from one end position to the other end position to switch the magnification, A first cam groove hole, which is rotatably disposed on the outer periphery of the system and into which the interlocking pin fixed to the movable lens frame of the photographing lens optical system is fitted in the inner periphery, and the finder optical system. A cam barrel having a second cam groove hole into which the outer periphery of the interlocking pin fixed to the movable lens frame is fitted, and a lens barrel for a video camera. 2. The video camera according to claim 1, wherein the first and second cam groove holes have straight portions having no movement amount in the optical axis direction at both ends. Lens barrel. 3. The video camera according to claim 1, wherein the first and second cam groove holes are formed by one cam groove hole having one end connected to each other. Lens barrel for use.