JP3214300B2 - Lens barrel with auxiliary lens system switching mechanism - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lens barrel having a switching mechanism for an auxiliary lens system, and more particularly, to a lens system having an auxiliary lens system inserted into and removed from an optical path of a main lens system so as to increase the focal length of the entire system. And a short focal length.

[0002]

2. Description of the Related Art Conventionally, an auxiliary lens system in which an auxiliary lens system is inserted into and removed from the optical path of a photographing lens (main lens system) to switch the focal length of the entire system between a long focal length and a short focal length for photographing. Various optical systems having a system switching mechanism have been proposed.

The switching mechanism at this time mainly sets switching means for inserting / removing the auxiliary lens system in the optical path of the main lens system and setting the position in the optical axis direction when the auxiliary lens system is inserted in the optical path. Locking means, which are attached to the camera body or to the rotating barrel of the lens barrel.

[0004]

The conventional auxiliary lens system switching mechanism cannot guarantee the operation of the lens barrel unit or the optical performance unless the lens barrel unit is inserted into the camera body. There is a problem that the lens barrel configuration becomes complicated.

Further, it is very difficult to accurately insert the auxiliary lens system at a predetermined position in the optical path of the main lens system, and it is difficult to maintain good optical performance.

The present invention provides a holding means for holding an auxiliary lens frame at a predetermined position in a lens barrel, a switching means for driving the auxiliary lens frame to be inserted into and removed from an optical path of a main lens system, and By properly setting the locking means for locking at a predetermined position in the axial direction, the auxiliary lens can be accurately inserted into a predetermined position in the optical path of the main lens system, and can be quickly retracted from the optical path. It is another object of the present invention to provide a lens barrel having an auxiliary lens system switching mechanism capable of switching the focal length of the entire system between a long focal length and a short focal length.

[0007]

SUMMARY OF THE INVENTION A lens barrel having an auxiliary lens system switching mechanism according to the present invention has the following features. (1) The auxiliary lens system is inserted into and removed from the optical path of the main lens system in conjunction with the rotation operation. A switching means for inserting and removing the auxiliary lens system into and from the optical path of the main lens system and a holding means for maintaining a retracted state of the auxiliary lens system from the optical path are provided on the rotary cylinder, and the rotary cylinder is rotatably fitted. The auxiliary lens system is provided with locking means for restricting the position in the optical axis direction when the auxiliary lens system is inserted in the optical path on a fixed barrel for supporting the entire lens barrel to the camera body and for supporting the entire lens barrel. I have.

(2) With the rotation of the rotary barrel, the notch provided in the rotary barrel is positioned on an axis for holding the retracted state of the auxiliary lens frame, and the auxiliary lens frame is set in a free state. The auxiliary lens system is inserted into the optical path of the main lens system by rotating about a support shaft provided on an arm connected to the auxiliary lens frame with an elastic member engaged with the lens frame, and connected to the auxiliary lens frame. The arm contacts the stopper provided on the blade holder to restrict the position in the direction orthogonal to the optical axis, and the locking portion provided on the auxiliary lens frame contacts the stopper of the fixed barrel when the rotary barrel rotates. It is characterized in that it contacts and locks.

[0009]

1 to 6 show the essential parts of a first embodiment of the present invention. FIG. 1 is a cross-sectional view showing a state in which the focal length of the entire system in which the auxiliary lens frame 8 retreats outside the imaging optical path of the main imaging lens system 7 is in a short focus state, and FIG. FIG. 3 is a cross-sectional view showing a state in which the focal length of the entire system that has entered the photographing optical path is in a long focus state. FIG. 3 is a rear view of a part of the lens barrel viewed from the rear in the state of FIG. 1, and FIG. 5 is a perspective view showing the relationship between the auxiliary lens frame 8 and the rotary barrel 2, FIG. 5 is a rear view of a part of the lens barrel viewed from the rear in the state of FIG. 2, and FIG. FIG. 4 is a perspective view illustrating a relationship between the rotary cylinders 2.

1 to 6, reference numeral 1 denotes a fixed barrel, which is fixed to a camera body (not shown) with screws, and has a helicoid screw 1a on the inner periphery thereof and a photographic optical system (a main lens system 7 and an auxiliary lens system 9). ) For moving straight in the optical axis direction
And an auxiliary lens frame 8 to be described later when the entire system is in a long focus state.
A stopper (locking means) 1c is provided for setting a position in the optical axis direction when is inserted in the optical path.

Reference numeral 2 denotes a rotary cylinder, which is rotatably fitted and supported on an outer periphery of a flange 3a of a rear base plate 3 described later.
A helicoid screw 2 a is formed on the outer periphery of the rotary cylinder 2 and is screwed with the helicoid screw 1 a of the fixed cylinder 1. A gear 2b interlocking with a known lens barrel driving system is formed on the inner periphery of the rotating cylinder 2, and the rotating cylinder 2 is moved by the lens barrel driving system to the rear base plate 3
Rotates along the outer periphery of the flange portion 3a,
Along the helicoid screw 1a in the optical axis direction.

A shutter unit 5 and a photographing optical system are supported in the optical axis direction in front of the rotary cylinder 2.
A rib (holding means) 2d having a cutout (switching means) 2c for retracting the auxiliary lens frame 8 outside the imaging optical path of the main lens system (main imaging lens system) 7 or entering the imaging optical path.
Is provided. Reference numeral 3 denotes a rear base plate, which is fixed to the blade retainer 4 with screws, and has a flange portion 3a which rotatably fits and supports the rotary cylinder 2 on an outer periphery thereof, and a shaft 8b of an auxiliary lens frame 8 described later on a flat surface portion. A shaft hole 3b is formed so as to be rotatably and reciprocally fitted and supported.

Reference numeral 4 denotes a blade holder, which is fixed to the shutter unit 5 with a screw, and is supported in the optical axis direction at the tip of a rib 2d of the rotary cylinder 2. The outer periphery of the blade holder 4 is formed with a convex portion 4a which is slidably fitted to the rectilinear groove 1b of the fixed cylinder 1 and moves linearly in the optical axis direction along the rectilinear groove 1b of the fixed cylinder 1. . In addition, a shaft hole 4b for fitting and supporting a shaft 8c of an auxiliary lens frame 8 to be described later so as to be able to rotate and advance and retreat, and a shaft 4c for hanging a tension spring 10 on a plane portion of the blade plate 4.
And a stopper 4d for setting the position of the auxiliary lens frame 8 in the direction orthogonal to the optical axis.

Reference numeral 5 denotes a shutter unit, which incorporates a known shutter drive system and a known lens barrel drive system. 6
Denotes a main lens frame, and a main photographing lens system (main lens system) 7
And is held by the shutter unit 5. 8
Denotes an auxiliary lens frame, which holds an auxiliary lens system 9 and has an L-shaped arm 8a, and support shafts 8b provided before and after the arm 8a.
8c and a shaft 8d on which a tension spring (elastic member) 10 is hung.

The support shaft 8b is provided in the shaft hole 3b of the rear base plate 3,
The support shaft 8c is rotatably and reciprocally fitted and supported in the shaft hole 4b of the blade holder 4, respectively.
Rotates around the support shafts 8b and 8c, and retracts out of the photographing optical path of the main photographing lens system 7 or enters the photographing optical path. At the end of the arm 8a, a locking portion 8e is provided for locking to the stopper 1c of the fixed cylinder 1 when the entire system is in the long focus state. The locking portion 8e has a rib 2d of the rotary cylinder 2.
A shaft 8f is provided, which is brought into contact with the inner periphery and retracted outside the imaging optical path of the main imaging lens system 7, and which holds the retracted state.

Reference numeral 10 denotes a tension spring, which comprises a spring for urging the auxiliary lens frame 8 in a clockwise direction (a direction in which the auxiliary lens frame 8 enters the photographing optical path of the main photographing lens system 7).
One end is hung on the axis 4c of the blade holder 4, and the other end is hung on the axis 8d of the auxiliary lens frame 8. Reference numeral 11 denotes a compression spring (elastic member) which is disposed between the auxiliary lens frame 8 and the rear base plate 3 and presses the auxiliary lens frame 8 forward to stabilize the lens interval when the entire system is in a long focus state. ing. 12
Denotes a lens barrel cover, which covers the photographing optical system and the shutter unit 5.

In this embodiment, the focal length of the entire system is switched from the short focus state to the long focus state by inserting the auxiliary lens system 8 in the optical path in the above configuration. That is, the rotating barrel 2 is rotated counterclockwise along the outer periphery of the flange 3a of the rear base plate 3 by the lens barrel driving means (not shown) from the state of FIG. 1 to the state of FIG. At this time, the rotary cylinder 2 moves along the helicoid screw 1a of the fixed cylinder 1 while pushing the blade holder 4 (shutter unit 5, photographing optical systems 7, 8) forward.

Since the convex portion 4a of the blade holder 4 is slidably fitted in the rectilinear groove 1b of the fixed cylinder 1, the shutter unit 5, the photographing optical system 7, and the light optics 7 and 8 extend along the rectilinear groove 1b. It moves straight in the axial direction. At this time, since the shaft 8f provided in the locking portion 8e is in contact with the inner periphery of the rib 2d of the rotary cylinder 2 as shown in FIG. Move forward while maintaining the retracted state.

As shown in FIG. 6, while the rotary barrel 2 is moving (before the long focal point of the entire system), a notch 2c provided in a rib 2d of the rotary barrel 2 is Rotate up to. Then, the auxiliary lens frame 8 is in a free state, and the auxiliary lens frame 8 is supported by the supporting shafts 8b and 8c by the spring force of the charged tension spring 10.
And enters the photographic optical path of the main photographic lens system 7. At this time, the arm 8a of the auxiliary lens frame 8 is provided with a stopper 4d provided on the blade holder 4 as shown in FIG.
, Which determines the position in the direction orthogonal to the optical axis. Thereafter, the rotating barrel 2 continues to rotate, and the locking portion 8e of the auxiliary lens frame 8 is locked to the stopper 1c of the fixed barrel 1.

As a result, the position in the optical axis direction is determined, and a long focal state is established as shown in FIG. When the focal length of the entire system is switched from the long focal state to the short focal state, the rotating barrel 2 is moved clockwise around the outer periphery of the flange portion 3a of the rear base plate 3 from the state shown in FIG. To move the rotary cylinder 2 along the helicoid screw 1a of the fixed cylinder 1 while pushing the flange portion 3a of the rear base plate 3 backward. Further, since the convex portion 4a of the blade retainer 4 is slidably fitted in the rectilinear groove 1b of the fixed cylinder 1, the shutter unit 5, the photographing optical systems 7, 8 rectilinearly moves in the optical axis direction along the rectilinear groove 1b. Moving.

At this time, the auxiliary lens frame 8 which has entered the photographic optical path of the main photographic lens system 7 is pushed by the ribs 2d of the rotary cylinder 2 on the shaft 8f provided on the locking portion 8e, and charges the tension spring 10. While rotating, it rotates counterclockwise about the support shafts 8b and 8c. Thereafter, as shown in FIG. 4, the shaft 8f of the auxiliary lens frame 8 comes into contact with the inner periphery of the rib 2d of the rotary cylinder 2, thereby retracting the auxiliary lens frame 8 out of the imaging optical path of the main imaging lens system 7. Hold. Thereby, as shown in FIG. 1, the focal length of the entire system is set to the short focal state.

As described above, according to the present invention, the auxiliary lens frame 8 is retracted out of the photographing optical path of the main photographing lens system 7, or the photographing is performed by the rotating cylinder 2 for moving the photographing optical systems 7, 8 in the optical axis direction. A rib (holding means) 2d having a notch (switching means) 2c for holding the retracted state of the auxiliary lens frame 8 while entering the optical path is provided, and the auxiliary lens is rotated by rotating the rotary cylinder 2 using the rib 2d. Switching is performed by directly responding to a shaft 8f provided on the frame 8, and the auxiliary lens frame 8 is moved in the optical axis direction to the fixed cylinder 1 which is screwed with the helicoid screw 2a of the rotary cylinder 2 and fixed to the camera body (not shown). By providing a stopper (locking means) 1c that locks the lens unit, the operation and optical performance can be guaranteed in the lens barrel unit state. Further, it is ensured that the main photographing lens system 7 can be retracted out of the photographing optical path.

[0023]

According to the present invention, as described above, the holding means for holding the auxiliary lens frame at a predetermined position of the lens barrel, and the switching for driving the auxiliary lens frame to be inserted into and removed from the optical path of the main lens system. The auxiliary lens is accurately inserted into a predetermined position in the optical path of the main lens system by appropriately setting means, and locking means for locking the auxiliary lens frame at a predetermined position in the optical axis direction. , And a lens barrel having an auxiliary lens system switching mechanism capable of switching the focal length of the entire system between the long focal length and the short focal length.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing a short focus state in which an auxiliary lens frame is retracted outside a photographing optical path of a main photographing lens system according to a first embodiment of the present invention.

FIG. 2 is a cross-sectional view showing a long focus state in which an auxiliary lens frame has entered the optical path of a main photographing lens system in Embodiment 1 of the present invention.

FIG. 3 is a rear view of the auxiliary lens frame viewed from the rear in the state of FIG. 1 according to the first embodiment of the present invention;

FIG. 4 is a perspective view showing a relationship between an auxiliary lens frame and a rotary cylinder in the state of FIG. 1 according to the first embodiment of the present invention.

5 is a rear view of the auxiliary lens frame viewed from the rear in the state of FIG. 2 according to the first embodiment of the present invention.

FIG. 6 is a perspective view showing the relationship between the auxiliary lens frame and the rotary cylinder in the state of FIG. 2 according to the first embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Fixed cylinder 1a, 2a Helicoid screw 1b Straight groove 1c, 4d Stopper 2 Rotating cylinder 2b Gear part 2c Notch part 2d Rib 3 Rear base plate 3a Flange part 3b, 4b Shaft hole 4 Blade retainer 4a Convex part 4c, 8d, 8f axis Reference Signs List 5 shutter unit 6 main lens frame 7 main photographing lens system 8 auxiliary lens frame 8a arm 8b, 8c support shaft 8e locking portion 9 auxiliary photographing lens system 10 tension spring 11 compression spring 12 lens barrel cover

Claims (2)

(57) [Claims] 1. A switching means for inserting / removing an auxiliary lens system into / from an optical path of a main lens system to / from a rotary cylinder for inserting / removing an auxiliary lens system into / from an optical path of a main lens system in conjunction with a rotation operation. Holding means for holding the retracted state of the auxiliary lens system from the optical path, the rotatable cylinder rotatably fitted and supported, and the auxiliary lens system mounted on a fixed cylinder for supporting the entire lens barrel on the camera body. What is claimed is: 1. A lens barrel having an auxiliary lens system switching mechanism, wherein a locking means for regulating a position in an optical axis direction when inserted in an optical path is provided. 2. A rotation of the rotary barrel causes a notch provided in the rotary barrel to be positioned on an axis for holding the retracted state of the auxiliary lens frame, thereby setting the auxiliary lens frame to a free state, and The auxiliary lens system was inserted into the optical path of the main lens system by rotating about a support shaft provided on an arm connected to the auxiliary lens frame with an elastic member engaged with the frame, and connected to the auxiliary lens frame. The arm comes into contact with a stopper provided on the blade retainer to regulate the position in the direction perpendicular to the optical axis. When the rotary barrel rotates, the locking part provided on the auxiliary lens frame comes into contact with the stopper of the fixed barrel. A lens barrel having an auxiliary lens system switching mechanism, wherein the lens barrel is adapted to be locked.