JPH08179182A - Optical equipment - Google Patents

Abstract

PURPOSE: To restrain the fitting backlash of a moving lens barrel with a cam ring or a guiding barrel to the minimum even though the sensitivity of the moving lens barrel is high and to evade failure even when they are moved in an optical equipment where the moving lens barrel is moved in an optical axis direction by the rotation of the cam ring or the guiding barrel. CONSTITUTION: An elastic member 13 energizing the moving lens barrel 4 to the guiding barrel 2 is disposed in the vertical direction orthogonally crossing an optical axis around a roller 12 supported by the moving lens barrel 4 fitted in the cam groove 19 of the cam ring 1 and the guiding groove 18 of the guiding barrel 2.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical device having a movable lens barrel such as a lens having a focus adjusting function or a zoom lens.

[0002]

2. Description of the Related Art Conventionally, in order to precisely move a lens group for zoom magnification conversion or a lens group for focus adjustment of a zoom lens, a roller provided on a movable lens barrel supporting the lens group is provided with a cam groove of a cam ring. There is known a lens barrel which fits in a guide groove of the guide barrel and moves the movable barrel in the optical axis direction by rotating the cam ring or the guide barrel.

In the lens barrel having such a structure, there is looseness in the fitting between the movable barrel and the guide barrel. Conventionally, in order to reduce the looseness in fitting, either one of the barrels is in the vertical direction orthogonal to the optical axis. There is a lens barrel provided with a member for biasing the lens barrel.

Further, according to the optical device disclosed in Japanese Patent Laid-Open No. 5-80243, the movable lens barrel is overlapped between the movable lens barrel and the guide barrel in order to prevent the occurrence of looseness. An elastic member that generates a pressing force in the vertical direction is provided.

[0005]

However, in the above-mentioned conventional example, when the eccentricity sensitivity of the lens of the movable lens barrel is high, the image quality is deteriorated due to the posture difference due to the clearance of the fitting, and the movable lens barrel is also deteriorated. There was a problem that the image shaking was noticeable while moving.

Further, even if a member for displacing is provided, it is not always urged, so that there is a problem that fitting backlash always remains.

Further, as in the optical device disclosed in Japanese Unexamined Patent Publication (Kokai) No. 5-80243, an elastic member for generating a pressing force in the vertical direction orthogonal to the optical axis is provided on the circumference and frictional force is applied. For example, when the movable lens barrel is moved by an actuator such as a motor, it is necessary to use one with a large motor output because the friction of the sliding portion is large, and the shape of the optical device itself becomes large, which also causes a cost increase. There was also the problem that

The present invention has been made to solve the above problems, and an object thereof is to eliminate fitting backlash between a movable lens barrel and a guide barrel by a small frictional force.

[0009]

The invention according to claim 1 of the present application provides a movable lens barrel, a cam ring having a cam groove, a guide tube having a guide groove, the cam groove and the guide groove. In an optical device having a roller fitted to and supported by the movable lens barrel, which advances and retracts the movable lens barrel in the optical axis direction by the rotation of the cam ring or the guide barrel, in a vertical direction orthogonal to the optical axis. By arranging the elastic member for urging the movable barrel with respect to the guide barrel around the roller, the movable barrel is urged only in the periphery of the roller in the vertical direction orthogonal to the optical axis,
The frictional force between the movable lens barrel and the guide tube can be reduced. For this reason, the load does not become extremely large when the actuator is moved.

In the invention according to claim 2 of the present application, the elastic member is provided with one or more protrusions, and the movable lens barrel is provided with a recess for engaging the protrusions. Rotation and movement can be restricted around.

According to a third aspect of the present invention, the elastic member has an annular shape centered on a vertical direction orthogonal to the optical axis, is vertically displaceable, and urges the guide tube. By having a shape having two or more first protrusions and one or more second protrusions in the direction opposite to the first protrusion, the elastic member urges by point contact, and
A stable biasing force and direction can be obtained by the first protrusion of the location, and the second protrusion easily supports the movable lens barrel.

According to the invention of claim 4 of the present application, the first projection is cam groove or guide by engaging the second projection of the elastic member with the recess provided in the movable lens barrel. The rotation of the elastic member itself can be restricted so as not to fall into the groove.

In the invention according to claim 5 of the present application, since the elastic member is formed of synthetic resin, elastic force can be obtained by elastically deforming the synthetic resin, and the elastic force changes depending on the shape. The friction resistance can be reduced by selecting a material having excellent slidability. In addition, cost reduction can be achieved.

In the invention according to claim 6 of the present application, since the elastic member is made of metal, elastic force is obtained by elastically deforming the metal, and friction is provided by the excellent slidability of the metal surface. It is to reduce resistance and further improve durability.

In the invention according to claim 7 of the present application, since the eccentricity adjusting means for the lens group supported by the movable lens barrel is provided in the movable lens barrel, the lens supported by the movable lens barrel is When the sensitivity is high, it is possible to correct the deterioration of the image quality due to the eccentricity shift of the lens caused by the biasing of the movable lens barrel by the eccentricity adjusting means.

[0016]

【Example】

Example 1. Hereinafter, the present invention will be described in detail based on embodiments shown in the drawings.

FIG. 1 is a sectional view of a monofocal lens barrel for a single-lens reflex camera which is one of the optical devices according to Embodiment 1 of the present invention, and FIG. 2 is an enlarged detailed view of a portion A of FIG. is there.

Reference numerals L1 to L4 represent first to fourth group lenses, respectively, the first group lens L1 is a fixed group, and the second to fourth group lenses L2 to L4 are focusing groups. Focus adjustment is performed from infinity to a close range. When you do, move to the object side as a whole. The third lens group L3 is a floating lens group,
The amount of movement in the optical axis direction due to focusing is large with respect to the second and fourth lens units L2 and L4.

Reference numeral 1 is a cam ring having two kinds of cams formed on its circumference, and the first cam 20 is a second or fourth lens group L2, L.
This is because 4 is moved in the optical axis direction, and the second cam 19 is for moving the third lens unit L3 in the optical axis direction.

Reference numeral 2 is a guide tube, and the rear part is a fourth group lens L4.
And a guide groove 18 formed in the optical axis direction into which the roller 12 fits. A lens barrel 3 of the second group lens L2 is fixed to the guide barrel 2 so as to move integrally with the fourth group lens L4.

Numeral 4 is a third group base lens barrel as a movable lens barrel, which is provided with three concave portions 23 serving as roller seats on the outer periphery, and one of the roller seats is surrounded by the elastic member 13. An annular recess 21 for engagement is provided.

Reference numeral 5 denotes a third lens unit fixed to the base barrel 4.
This is a group lens barrel, and the third group lens barrel 5 can be eccentrically moved before being fixed to the third group base lens barrel 4, and functions as eccentricity adjusting means. Reference numeral 6 is a diaphragm mechanism driven by a drive unit (not shown), and is attached to the guide cylinder 2.

Reference numeral 7 represents an AF driving actuator disclosed in, for example, Japanese Patent Laid-Open No. 25321/1990,
The rotation of the focus key 9 about the optical axis appears as the output of the actuator 7. Reference numeral 8 is a manual ring having a structure capable of rotating the focus key 9.

Reference numeral 10 is a focus screw fixed to the guide tube 2, and is fitted in the first cam groove 20 of the cam ring 1 and the focus key 9. Reference numeral 11 denotes a first roller fixed to the guide tube 2 by a screw, and this roller 11 is fitted in the first cam groove 20 like the focus screw 10. Reference numeral 12 denotes a second roller fitted in the second cam groove 19 and the guide groove 18, and the roller 12 is fixed to the third group base barrel 4 with a screw 17.

Incidentally, the first and second cam grooves 20, 19 described above.
Is equally divided into three parts in the circumferential direction, and the focus screw 10 and the two rollers 11 are equally fixed to the guide tube 2, and the three rollers 12 are equally divided into the third group base lens barrel. Four
It is fixed to.

Reference numeral 14 denotes a mounting board, and an IC for driving the actuator is mounted on the board 14. 1
5 is a mount for connecting to the camera body 100,
Reference numeral 6 is a contact block for performing electrical communication with the camera body 100.

FIG. 3 is an enlarged sectional view of a part of the layer taken along the line BB of FIG. 1, and FIG. 4 is an exploded perspective view of the vicinity of the A portion of FIG. Reference numeral 13 denotes an elastic member which is made of a synthetic resin such as POM and has an annular shape centered on a vertical direction Y orthogonal to the optical axis, and between the two sides 13a and 13b provided with the protrusions 25 and 26. It can be elastically displaced in the Y direction.

Therefore, it is possible to easily change the elastic force according to the displacement amount, and it is also possible to easily change the elastic force according to the weight of the movable lens barrel. Since the protrusion 25 is formed so as to engage with the recess 22 in the annular recess 21 provided in the third group base barrel 4, the elastic member 1
3 does not rotate about the vertical direction Y. As a result, it is possible to prevent the protrusion 26, which is the point of application of the elastic force, from falling into the guide groove 18. Further, since the fitting backlash with the guide tube 2 is biased at a position symmetrical with the roller 12,
The fitting play, that is, the point of action of the elastic force of the elastic member 13 on the guide tube 2 is the protrusion 26 and the roller having no elastic member around it.

With the above arrangement, the one-sided direction is always constant. Therefore, if the lens in the movable lens barrel is adjusted to be eccentric, even a highly sensitive lens can be moved.

Example 2. FIG. 5 is a perspective view of an elastic member 13 showing a second embodiment of the present invention, in which a metal plate material is press-formed into a ring shape, and protrusions 30 and 31 are provided in directions opposite to each other on the X and Y axis lines thereof. With this configuration, the same effect as that of the elastic member 13 of FIG. 4 can be obtained. Since the projection 31 cannot be formed in the same phase as the projection 30, the phase of the recess 22 on the side of the third lens group base barrel 4 may be provided in the same phase as the projection 31.

Each of the above embodiments can be applied to a camera of an interchangeable lens system having a lens driving actuator in the camera, and a lens barrel for a video lens or a projector other than an interchangeable lens for a single lens reflex camera. It can also be applied to optical devices such as.

[0032]

As described above, according to the first aspect of the invention, the optical axis is provided only around the roller supported by the movable lens barrel that is fitted in the cam groove of the cam ring and the guide groove of the guide tube. Since the elastic member for urging the movable lens barrel against the guide barrel is arranged in the vertical direction orthogonal to the above, it is possible to eliminate the fitting backlash between the two barrels and to reduce the frictional force. For this reason,
The load does not become extremely large when moved by the actuator.

According to the second aspect of the present invention, since the movable lens barrel is provided with the recess to which the protrusion of the elastic member engages, the protrusion of the elastic member is prevented from falling into the cam groove or the guide groove. The rotation and movement of the member can be restricted.

According to the third aspect of the invention, the elastic member for urging the movable lens barrel with respect to the guide tube in the vertical direction orthogonal to the optical axis has an annular shape centered on the vertical direction and has the vertical direction. And a plurality of first projections that are capable of displacing the guide tube and that urge the guide tube, and 1 in the opposite direction of the first projections.
Since it is configured to have the second protrusions at or above the points, it is possible to urge by point contact, obtain a stable urging force, and easily support the movable lens barrel.

According to the fourth aspect of the invention, since the second protrusion of the elastic member is configured to engage with the recess of the movable lens barrel, the first protrusion falls into the cam groove or the guide groove. The elastic member can be easily supported so that the rotation of the elastic member can be restricted.

According to the invention of claim 5 or 6, since the elastic member is configured to obtain an elastic force by elastically deforming a synthetic resin or a metal, it is possible to select a material excellent in slidability. Further, the frictional resistance can be further reduced, and the cost can be reduced or the durability can be improved.

According to the seventh aspect of the invention, since the eccentricity adjusting means is provided in the movable lens barrel, even if the sensitivity of the lens is high, the eccentricity of the lens caused by urging the movable lens barrel is caused. It is possible to correct the deterioration of the image quality due to the deviation. For this reason, it is possible to prevent the deterioration of the image quality due to the posture difference, and it is possible to move the lens having high sensitivity, and it is possible to obtain the effect of increasing the degree of freedom in design.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a single-focus lens barrel for a single-lens reflex camera, which is one of the optical devices according to a first embodiment of the present invention.

FIG. 2 is an enlarged detailed view of a portion A of FIG.

3 is a partial enlarged cross-sectional view taken along the line BB of FIG.

FIG. 4 is a perspective view of an elastic member.

FIG. 5 is a perspective view of an elastic member showing Embodiment 2 of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 cam ring 2 guide cylinder 4 3rd group base lens barrel (moving lens barrel) 5 3rd group lens barrel (eccentricity adjusting means) 12 roller 13 elastic member 18 guide groove 19 cam groove

Claims (7)

[Claims] 1. A movable lens barrel, and a cam ring having a cam groove,
It has a guide tube having a guide groove, a cam groove and a roller fitted in the guide groove and supported by the movable lens barrel, and the movable lens barrel is moved to the optical axis by rotation of the cam ring or the guide tube. In the optical device for moving back and forth in a direction, an elastic device for urging the movable lens barrel against the guide barrel in a vertical direction orthogonal to an optical axis is arranged around the roller. 2. The optical apparatus according to claim 1, wherein the elastic member has one or more protrusions, and the movable lens barrel has a recess with which the protrusions engage. 3. The elastic member has an annular shape centered on a vertical direction orthogonal to the optical axis, is displaceable in the vertical direction, and has two or more first protrusions for urging the guide cylinder. And at least one second portion in the opposite direction of the first protrusion.
The optical apparatus according to claim 1, further comprising a protrusion. 4. The optical device according to claim 3, wherein the second protrusion of the elastic member engages with a recess provided in the movable lens barrel. 5. The optical device according to claim 1, wherein the elastic member is made of synthetic resin. 6. The optical device according to claim 1, wherein the elastic member is made of metal. 7. The optical apparatus according to claim 1, wherein the movable lens barrel is provided with eccentricity adjusting means for a lens group supported by the movable lens barrel.