JPS5934885Y2 - Support structure of lens holding member of lens barrel - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a support structure for a movable member of a lens barrel, particularly for a lens holding member.

In zoom lenses, rear focus lenses, etc., the structure for movably supporting the lens holding member in the optical axis direction is to form a straight groove in the fixed barrel of the lens barrel, and insert a guide member such as a key member into the straight groove. A structure in which the lens holding member is integrally connected to the guide member with screws or the like and supported is often used.

In this conventional structure, it was necessary to maintain high finishing accuracy on the fitting surface between the fixed barrel and the lens holding member, which resulted in problems such as an increase in the number of processing steps and parts retention.

In the present invention, a tapered surface having a slope in the direction of the optical axis center is formed on the side wall surface of a straight groove formed in a fixed barrel of a lens barrel, and a guide member is fitted into the straight groove, and the guide member is In this structure, a tapered surface having the same slope as the tapered surface of the straight groove is formed on the side wall, and the lens holding member is supported by being coupled to the guide member.

Embodiments of the present invention will be described in detail below with reference to the drawings.

FIG. 1 shows an axial cross-sectional view of a zoom lens barrel to which the present invention is applied. 1a
1 and 1a2 are provided, and the side surfaces 1b1 and 1b2 along the optical axis direction of the rectilinear groove 1a1 are rays (indicated by two-dot chain lines) centered on the optical axis O as shown in FIG.

) has a tapered surface formed along.

The fixed barrel 1 has a mounting means (for example, a bayonet mount) 2 on the rear end side for mounting the zoom lens on the camera.

Reference numeral 3 denotes a cam barrel member which is fitted to the fixed barrel 1 so as to be rotatable relative to the optical axis, and the cam barrel 3 has a cam barrel member on its circumferential surface with a movement amount in the optical axis direction of a lens holding member, which will be described later. Cam grooves 3a and 3b for control are formed.

4 is a vericoid ring fitted inside the fixed barrel 1, which has a helicoid screw 4a on the inner periphery, and which is connected to the first lens group L.
The ring 4 is threadedly engaged with the helicoidal screw 5a of the second lens holding member 5 that holds lenses 1 to L5, and the ring 4 has a pin 4b that is inserted into the intersection of the straight groove 1a2 and the cam groove 3b.

Reference numeral 6 denotes a distance adjustment ring coupled to the second lens holding member 5, and is configured to be positioned in the minimum H-law of the lens barrel.

7 and 8 constitute the second lens holding members of the ON lens groups L6 to L1o, and the holding members 7 and 8 are approximately cylindrical in shape as shown in FIGS. 2 and 3a, and have lenses on their inner surfaces. The abutment surfaces are provided, and the lenses are sequentially housed and tightened by fixing the lenses with a ring 9, and the holding members 7 and 8 are integrally connected with screws.

In the gap between the holding members 7 and 8, there is an aperture unit (the aperture blades are simply shown in the figure).

) and is coupled to the aperture setting ring 10 fitted to the fixed cylinder 1 so as to be interlocked by known means.

Reference numeral 11 denotes a guide member fitted into the rectilinear groove 1a of the fixed barrel, and side surfaces 11a1.11 of the guide member 11 along the optical axis direction.
11a2 is brought into contact with the tapered surface formed on the side surface of the straight groove 1a1.

In addition, when the guide member 11 is formed in an arc shape that matches the arc shape centered on the optical axis O when viewed from a cross section perpendicular to the optical axis of the straight grooves 1 al and 1 a 2, the guide member 11 is formed into an arc shape that matches the arc shape centered on the optical axis O when viewed from a cross section perpendicular to the optical axis of the straight grooves 1 a1 and 1 a2. Good sliding properties.

In addition, as shown in FIG. 3, the guide member 11 has tapered side surfaces 11a1 and 11a2 with escape portions 11c1 and 11c2 for reducing frictional resistance during sliding, and a straight groove 1a.
It has slots 11d1 and 11d2 in order to apply appropriate side pressure to the side surfaces 1b1 and 1b2 of 1.

Further, the guide member 11 has the cam groove 3 of the cam cylinder 3 on its upper surface.
a protruding engaging portion 11A for engaging with the engaging pin portions 11B1 and 11B2 formed on the lower surface of the engaging portion 11A, and FIG.
A hole 1 into which the diameter portion 12a of the eccentric adjustment member 12 shown in FIG.
1D, and an elongated hole 11 for tightening and fixing a branch 7A formed extending from the outer periphery of the lens holding member 7 in the optical axis direction, which will be described later.
They each have E.

11F is a chamfered portion for tightening screws.

As described above, a support portion 7A is formed extending from the outer periphery of the lens holding member 7 in the optical axis direction, and the support portion 7A has an elongated hole or groove 7 into which the engagement pin portion 11B111B2 of the guide member 11 is fitted. al, 7 a2, a circumferential hole or circumferential groove 7b around the optical axis into which the engagement pin 12b of the eccentric adjustment member 12 is fitted, and a lens holding member 7, which is connected to the guide member 11 via the support portion 7A. It has a screw hole 7c for coupling 8.

The supporting portion 7A of the lens holding member of the guide member 1, the eccentricity adjusting member 12, etc. form the position adjusting mechanism of the lens holding member of this embodiment.

Next, the assembly, adjustment, and operation of the adjustment mechanism will be described.

The guide member 11 is fitted into the straight groove 1al of the fixed cylinder 1, and the protruding engaging portion 11A is engaged with the cam groove 3a of the cam cylinder 3.

Next, the eccentric adjustment member 12 is fitted into the hole 11b of the guide member 11.

Next, the supporting portion 7A of the lens holding member is temporarily fastened to the lower surface of the guide member 11 using the screws 13.

By this tightening, the engaging pin portions 11B1, 1 of the guide member
1B2 fits into the long grooves 7a1 and 7a2 of the support portion 7A, and the pin portion 12b of the eccentric adjustment member 12 fits into the circumferential groove 7b.

In this state, to adjust the distance from the predetermined reference position of the second lens group L6 to L1o to the predetermined design (assembly) reference position of the lens barrel, turn the split groove 12c of the eccentricity adjustment member 12 with a screwdriver etc. The adjustment member has a hole 1 in the guide member 11.
1b, and the eccentric pin 12b also rotates accordingly.

Since the eccentric pin 12b is fitted into the circumferential groove 7b, as the eccentric pin 12b rotates, it is displaced within the circumferential groove 7b of the support part 7A, that is, the second lens holding members 7, 8.
Move and adjust the entire unit in the optical axis direction.

When the second lens holding member 7°8 is in the specified position, screw the screw 13
Tighten.

By this adjustment operation, the protruding engagement portion 11A of the guide member 11
The position of the intersection between the cam groove 3a and the straight groove 1a1 can be adjusted.

Then, by tightening the screws 13, the second lens holding members 7 and 8 are coupled to the guide member 11, and the eccentricity adjusting member is also fixed in the press-fit hole 7c of the guide member 11.

With the above configuration and adjustment, the second lens groups L6 to L1o are adjusted to predetermined positions within the lens barrel, and the optical performance of the zoom lens is maintained.

Reference numeral 14 denotes a joint shell that covers the outer periphery of the fixed shell.

As described above, the present invention provides the side surfaces 1b1 and 1b2 of the linear groove 1a1 of the fixed barrel 1 constituting the lens barrel with a tapered surface having a slope in the direction of the center of the optical axis, and also provides a guide member that fits into the linear groove. A tapered surface that fits with the tapered surface is formed on the side walls 11al and 11a2 of 11, and the lens holding member 7 is coupled to the guide member 11 to support the lens holding member 7 movably in the optical axis direction with respect to the fixed barrel 1. It has a structure that
In the present invention, the lens holding member 7 has the tapered surface 1
Since it is supported by 1a1, 11a2 and 1b1°1b2, by keeping the surface precision of the tapered surface high, it is possible to improve the support position of the lens holding member and the axial center precision when moving in the optical axis direction, and the lens It is possible to obtain a lens barrel in which the optical members of the lens barrel have high optical performance.

In addition, in FIGS. 1 and 2, the guide member 11 has a support portion 7A.
When they are combined and fitted into the rectilinear groove 1a1, they fit into the fixed cylinder 1 at surfaces D1 to D4 shown in FIG.

In particular, the lens holding member 7 has a tapered surface D1 of the side wall of the guide member 11. While being supported by the fixed cylinder 1 by D2,
Sliding surface D3 between the support portion 7A and the inner circumferential surface of the fixed cylinder 1. Slide into contact with D4.

Therefore, the lens holding member 7 can stably move along the fixed barrel 1 in the optical axis direction.

[Brief explanation of the drawing]

FIG. 1 is an axial sectional view of a lens barrel to which an embodiment of the present invention is applied. FIG. 2 is a sectional view in the optical axis direction A1A2 of FIG. FIG. 3a is a perspective view of the lens holding member. FIG. 3 is a perspective view of the guide member. FIG. 3C is a sectional view of the guide member in the optical axis direction. FIG. 3d is a perspective view of the eccentric adjustment table [material]. 1... Fixed cylinder, lal... Straight groove, holding member, 11... Guide member. 7... Lens

Claims (1)

[Scope of utility model registration request] a first barrel member of the lens barrel has a straight groove in the optical axis direction;
A side wall of the rectilinear groove is formed as a tapered surface with a slope, a guide member having a side wall that fits into the tapered surface is engaged with the rectilinear groove, and a lens holding member holds a lens optical system on the guide member. A support structure for a lens holding member of a lens barrel, characterized by combining the following.