JPS599042B2 - lens structure - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a lens structure such as a zoom lens.

In order to obtain a zooming effect, a variator lens and a compensator lens are provided, and the variator lens and compensator lens are related to each other and moved along the optical axis by a mechanical cam, thereby providing the zooming effect. So-called zoom lenses are well known.

In recent years, efforts have been made to make zoom lenses more compact by reducing their size and weight in order to improve their operability. However, this compactness of zoom lenses has created a need to reduce assembly errors of each lens unit more than ever before. ing.
This is because by making the lens more compact, the curvature of each lens becomes smaller, making it a more effective lens, so the tilt and parallel eccentricity between each lens have a greater effect on imaging performance. It is for the sake of being there. Generally, the lens structure of a zoom lens consists of five groups: a focus lens, a variator lens, a compensator lens, an afocal lens, and a relay lens.The middle focus lens is moved by a helicoid along the optical axis of the zoom lens, and the variator lens The compensator lens is moved along the optical axis by the action of a mechanical cam, while the afocal lens and relay lens are fixed without moving.

Therefore, when configuring a zoom lens, positioning of the optical axis is easy because the rear focal lens and relay lens are fixed to a fixed member, and the focus lens also does not directly contribute to zooming. However, since the variator lens and compensator lens are moved by mechanical cams, it is the most difficult to improve assembly accuracy. When comparing the tele end (telephoto end) and wide end (wide angle end) of zooming, if there is an optical axis error between the variator lens and the compensator lens with other lenses, the variator lens and the compensator lens Comparing when the lens is moving to the telephoto end and when it is moving to the wide end, the effect of the optical axis error becomes larger as you move from the wide end to the telephoto end, especially when the variator at the telephoto end The inclination and parallel eccentricity of the lens have a large effect on imaging performance. An object of the present invention is to provide a lens structure having a structure in which assembly errors of the lens structure, particularly parallel eccentricity and inclination, can be adjusted.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The lens structure of a camera according to the present invention will be described in detail below with reference to the drawings, taking a zoom lens structure as an example.

FIG. 1 is a cross-sectional view in the optical axis direction of a lens assembly according to the present invention attached to a camera.

Referring to FIG. 1, a preferred structure of a camera to which a lens structure according to the present invention is attached and used will be explained.

Reference numeral 32 denotes a camera body, and 23 a half mirror fixed to the camera body 32. The half mirror 23 is used to separate an incident subject into a film surface 31 and a viewfinder optical system.

25 and 27 are finder lenses fixed to the camera body 32, and 26 is a mirror fixed to the camera body 32, and the mirror 26 reflects the subject light passing through the finder lens 25 toward the finder lens 27. It is for.

28 is a relay lens fixed to the camera body 32;
A half mirror 30 separates the subject light passing through the relay lens 28 toward the light receiving element 34 and the film surface 31.

29 is an aperture device having an aperture member 29a disposed between the half mirror 23 and the relay lens 28;
It is fixed at 2.

33 is a photometric device for controlling the aperture device 29 according to the amount of light from the object received by the light receiving element 34.

35 is a rotary shutter blade disposed between the half mirror 30 and the film surface 31.

A cinema configured like this. In the camera, the subject light incident on the half mirror 23 is...
At step 3, part of the light passes through the finder optical system 25, 26, 27, and the other part passes through the relay lens 28 and reaches the half mirror 30.

The light reaching this half mirror 30 is
At 0, a part is attached to the light receiving element 34, and the other part is attached to the film 31.
incident in the direction. Then, when the subject light is incident on the light receiving element 34, the photometer 23 controls the aperture device 29 according to the amount of light incident on the light receiving element 34, thereby causing the aperture member 29a to properly expose the film surface 31. control so that The configuration of this camera body device is a generally known structure. Next, the structure of a lens structure (zoom lens structure in the embodiment shown in FIG. 1) applied to the camera body as described above will be explained.

Reference numeral 6 denotes a fixed barrel fixed to the front surface of the camera body 32 with a pin 24, and a convex helicoid 6a is provided on a part of the outer peripheral surface of the fixed barrel 6.

Further, an afocal lens 22 is held on the end surface 6b of the fixed barrel 6 on the side fixed to the camera body 32,
An adjustment hole 6c is provided on the circumferential surface thereof, and an elongated hole 6d extending in the circumferential direction of the fixed cylinder 6 is formed. Reference numeral 10 denotes a cam ring disposed within the fixed cylinder 6, and the cam ring 10 is rotatably supported on the inner wall of the fixed cylinder 6.

Further, the cam 10 is provided with cam grooves 10a and 10b, and an adjustment hole 10c is provided at a position corresponding to the adjustment hole 6c provided in the fixed cylinder 6. Reference numeral 11 denotes a planting pin that passes through the elongated hole 6d of the fixed cylinder 6 and is planted on the outer peripheral surface of the cam ring 10. The planting pin 11 rotates the cam ring 10 in response to a zooming operation from the outside. It is for the purpose of

A zoom operation ring 8 is rotatably supported on the outer peripheral surface of the fixed cylinder 6Q, and the zoom operation ring 8 is provided with an adjustment hole 8a and a pin insertion hole 8b.

The adjustment hole 8a of the zoom operation ring 8 is used to adjust the fixed barrel 6 when the zoom operation ring 8 is rotated to a position where the zoom optical system (not shown) constituting the zooming lens is placed at the telephoto end. It is formed at a position corresponding to the hole 6c (and the end of the pin 11 is engaged with the pin insertion hole 8b. Therefore,
By rotating the zoom operation ring 8 from the outside, the pin 11 moves within the elongated hole 6d of the fixed cylinder 6 as the zoom operation ring 8 rotates, and the movement of the pin 11 causes the cam ring 10 to rotate. It's starting to move. Reference numeral 9 indicates that the adjustment hole 8a and pin insertion hole 8b provided on the zoom operation ring 8 are not visible from the outside. A rubber ring is provided to cover the zoom operation ring 8, and the outer surface of the rubber ring has irregularities to prevent the hand rotating the zoom operation ring 8 from slipping.

Guide rods 7a, 7b, and 7c have one end fixed to the end surface 6b of the fixed tube 6 and the other end fixed to the end plate 5, and are arranged approximately parallel to the optical axis 0.

16 is a variator lens; 13 is a lens holder that holds the variator lens 16; 12 is a movable ring that supports the lens holder 13;
2 is a cam groove 10a of the cam ring 10 when the cam ring 10 rotates.
The lens holder 13 and the variator lens 16 move in the direction along the optical axis 0 while being regulated by the lens holder 13 and the variator lens 16. , an adjustment means is provided to adjust the error when the optical axis of the variator lens 16 deviates from the regular optical axis 0.
The detailed structure of the adjusting means will be described later using FIGS. 2 to 4.

The movable ring 12 is provided with a screw hole on its circumferential surface for an adjustment means to be described later, and the cam groove 1 of the cam ring 10 is
A pin 18 that is engaged with the guide rod 0a is implanted on the circumferential surface, and a sleeve 12a through which the guide rod 7b is passed and an engaging portion 12c that is engaged with the guide rod 7a are provided. . When the cam ring 10 is rotated, this movable ring 12
A pin 18 engaged with the cam groove 10a of the cam ring 10
The movable ring 12 is adapted to move along the optical axis 0 by receiving an acting force in the direction along the optical axis 0 through the movable ring 12,
As the moving ring 12 moves, the lens holder 12 and the variator lens 16 also move, and the position of the variator lens 16 on the optical axis 0 changes.
When the movable ring 12 moves under the action of the cam ring 10, the sleeve 12a tilts.
It has the role of preventing the optical axis of the variator lens from being tilted with respect to the normal optical axis 0.
The length along the direction is sufficient. Moreover, the engaging part 1
When the movable ring 12 moves under the action of the cam ring 10, the rotation imparting force is applied to the guide rod 2c so that the movable ring 12 does not rotate due to the rotational action of the cam ring 10. 7a
It also serves as a regulator. 17 always keeps the moving ring 12
A coil spring is biased toward the left in FIG. 1, and the spring 17 presses the pin 18 against one side wall of the cam groove 10a, thereby preventing the movable ring 12 from shaking during movement. This spring 17 is arranged on the guide rod 7b.

20 is a compensator lens, and 19 is a movable ring that also serves as a lens holder that holds the compensator lens 20 fixedly.

This movable ring 19 has a cam ring 10 similar to the movable ring 12.
A pin 21 that is engaged with the cam groove 10b is provided on the circumference, and a sleeve 19a through which the guide rod 7c (second illustration) is passed is engaged with an engaging portion where the guide rod 7a is engaged. 19b is provided. The movable ring 19 configured in this way also moves when the cam ring 10 is rotated.
The movable ring 19 is configured to receive an acting force in the direction along the optical axis 0 through a pin 21 engaged with the cam groove 10b of the cam groove 10b of the movable ring 19, so that the movable ring 19 moves along the optical axis 0. The compensator lens 20 also moves together with the movement of the ring 19, and the position of the compensator lens 20 on the optical axis 0 changes. That is, when the cam ring 10 is rotated by the rotation operation of the zoom operation ring 8, the movable rings 12 and 19 are regulated by the cam grooves 10a and 10b of the cam ring 10, and move relative to each other along the optical axis 0. It's starting to move around.

Usually, the moving rings 12 and 19 have greatly different rates of movement along the optical axis 0 relative to the amount of rotation of the cam ring 10. As can be seen from FIG. 1, the amount of movement of the movable ring 19 to move the compensator lens 20 is, if the state shown in FIG. Although the movement of the movable ring 12 only changes to the position shown in FIG. 1, if the state shown in FIG. Therefore, compensator lens 2
Even if the optical axis of the variator lens 16 is slightly parallel and decentered or tilted with respect to the normal optical axis 0, there is little optical effect, but in the case of the variator lens 16, the optical axis of the variator lens 16 moves significantly, so the optical axis of the variator lens 16 is not normal. If the variator lens 16 is parallel and decentered or inclined to the optical axis 0 at the wide end, it will greatly affect the optical performance when the variator lens 16 is moved to the telephoto end. A method for removing the optical influence due to the parallel eccentricity or inclination of the variator lens 16 is the role of the adjustment means described later. Further, 1 is a focusing lens, and 2 is an annular focusing holder 1 that holds the focusing lens 1 fixedly. A concave helicoid 2a that engages with a convex helicoid 6a provided on the outer circumferential surface of the fixed barrel 6 is formed on a part of the inner circumferential surface of the lens holder 2, and when the lens holder 2 is rotated, a concave helicoid 2a is formed. Due to the action of the convex helicoid 6a and the concave helicoid 2a, the lens holder 2 moves back and forth depending on its rotation direction. By moving the lens holder 2 back and forth, the focusing lens 1 moves on the optical axis 0. 3
is a distance ring fixed to the outer peripheral surface of the lens holder 2,
Reference numeral 4 denotes a rubber ring fixed to the outer peripheral surface of the distance ring 3. The rubber ring 4 is used to prevent the operator's hand from slipping when rotating the distance ring 3. The outer surface of the rubber ring 4 is There are unevenness.

Next, a method for adjusting the optical axis of the variator lens 16 when it is decentered or tilted parallel to the normal optical axis 0 will be explained. FIGS. 2 and 3 show in detail the means for adjusting the optical axis of the variator lens 16 when it is eccentrically parallel to the normal optical axis 0. This adjusting means is the moving ring 1
2, and a screw 1 screwed into the screw hole of the moving ring 12.
51, 152, 153, and a biasing spring 14 disposed between the movable ring 12 and the lens holder. The spring 14 moves the lens holder 13 as shown in FIG.
This is because it is constantly biased in the direction of arrow A. Also, a movable ring 1 for screwing in the screws 151, 152, 153.
When the movable ring 12 is moved to the telephoto end, the screw holes provided in the adjustment holes 10C1, 10C2>10C
3,6C1,6C2,6C3,8C,,8C2,8C3
and are placed in corresponding positions,
The screws 151, 152, 153 are screwed in by inserting a screwdriver into the adjustment holes 10C, 6C, 8C. Adjustment of parallel eccentricity by the adjustment means configured in this way is performed by screws 151, 152, 153.
This is done by changing the amount of screwing in and moving the position of the lens holder 13 within the movable ring 12. Next, FIG. 4 shows in detail the means for adjusting the inclination when the optical axis of the variator lens 16 is inclined with respect to the normal optical axis 0. 13C is a boss hole provided in the lens holder 13, and 12C is a screw hole provided in the movable ring 12.

Reference numeral 41 represents an adjustment screw screwed into the screw hole 12C through the boss hole 13C, and 40 represents a compression spring disposed on the adjustment screw 41 between the lens holder 13 and the movable ring 12.

19C is the lens holder 1 when the variator lens 16 and compensator lens 20 reach the telephoto end.
A through hole 6b is formed at the position of the movable ring 19 corresponding to the screw hole 13C of No. 3, and when the variator lens and the compensator lens 20 reach the telephoto end,
End surface 6 of fixed cylinder 6 corresponding to through hole 19e of moving ring 19
This is the through hole formed in b.

Means for such adjustment is provided at three locations as shown in FIG. The inclination of the optical axis 01 of the variator lens 16 can be adjusted by adjusting the screwing amount of the screw 41 using the adjusting means configured as described above. That is, when one of the adjustment screws 41 of the three adjustment means is screwed in or pulled down, the part operated by that screw 41 tilts with respect to the other parts. It is possible to arbitrarily align the inclination of the optical axis 0 of the variator lens 16 with the normal optical axis 0 by using the adjusting means as needed. As explained above, since the lens structure according to the present invention allows the inclination or parallel eccentricity of the lens to be adjusted extremely easily after the lens structure is assembled, there may be some manufacturing errors during component manufacturing and assembly errors. This has the advantage of being easy to manufacture and easy to assemble.

[Brief explanation of drawings]

FIG. 1 is a sectional view in the optical axis direction of a lens assembly according to the present invention attached to a camera. FIG. 2 is a sectional view taken along the line -- in FIG. 1. FIG. 3 is an exploded perspective view showing a means for adjusting the lens structure shown in FIG. 1 when the optical axis of the variator 1/lens 16 is eccentric and parallel to the normal optical axis. Figure 4 is the first
In the lens structure shown in the figure, the variator lens 1
FIG. 6 is an axial cross-sectional view showing in detail a means for adjusting the optical axis of No. 6 when it is tilted with respect to the normal optical axis. FIG. 5 is a plan view of the adjusting means shown in FIG. 4, viewed from the negative direction. 12...Moving ring, 151, 152, 153
...Adjustment screw, 14... Offset spring, 10C1, 10C2, 10C3, 6C1, 6C2, 6
C3, 8C,, 8C2, 8C3...adjustment hole, 1
3...Lens holder 12C...N.
Hole, 13C...Boss hole, 41...Adjustment screw, 40...Compression spring.

Claims (1)

[Claims] 1. A lens holder holding a lens, a movable ring that moves along the optical axis by an operating member, and at least a portion of the outer circumference of the lens holder and the inner circumference of the movable ring in a direction parallel to the optical axis. The lens holder and the movable ring are arranged one on top of the other, and a spring member is interposed between the outer circumference of the lens holder and the inner circumference of the movable ring, and a locking member such as a screw is used to lock the lens holder and the movable ring, and the locking member A lens structure characterized in that the eccentricity of the lens holder is adjusted by adjusting.