JP2562143Y2 - Lens barrel - 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 so-called short distance correction mechanism and a distance encoder which changes a distance between lenses according to a photographing distance, and particularly to a case in which a back of a lens is taken out. In addition, the present invention relates to a lens barrel that facilitates various adjustments such as setting a reference position of a distance encoder.

[0002]

2. Description of the Related Art Conventionally, in a lens barrel of this type, in order to bring out a back of a lens, a helicoid in the middle of a double helicoid is rotated, a lens system is moved in an optical axis direction, and a film surface position is adjusted. After focusing, the distance ring and the rotation limiting member were adjusted to an infinite position.

[0003] In addition, some lens barrels have a built-in distance encoder for communicating distance information of a subject to a camera body.

[0004]

However, when the lens barrel has a short distance correction mechanism, the short distance correction mechanism is rotated integrally with the distance ring by a lever or the like which engages with the distance ring. Because the distance is corrected, if the helicoid in the middle of the double helicoid is rotated to move the lens system in the optical axis direction in order to bring out the lens back, the short distance correction mechanism also rotates at the same time, infinite There is a problem that the reference distance between the master lens and the correction lens in a large size is shifted.

When the distance encoder is built in the lens barrel, the distance encoder is also linked with the rotation of the distance ring. When the lens system is moved in the optical axis direction by rotating the middle helicoid of the double helicoid, the distance encoder also rotates at the same time, and the reference position of the distance encoder at infinity is shifted. .

The present invention has been made in view of such a conventional problem, and when performing backing, both the short distance correction mechanism and the distance encoder can hold the reference position at the infinite position. It is an object to provide a lens barrel.

[0007]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, a lens barrel according to the present invention is a lens barrel having a short-distance correction mechanism and a distance encoder, and is integrated with a helicoid in the middle of a double helicoid. A first distance ring to be fixed; a second distance ring to which a lever for engaging with the short distance correction mechanism and a brush for the distance encoder are fixed, and further provided with a rotation limit; The first distance ring and the second distance ring are integrally fixed after the back ring is adjusted by rotating only the distance ring.

[0008]

According to the present invention, since the above-described configuration is employed, even if the intermediate helicoid between the double helicoids is rotated and the lens is retracted, the short-distance correction mechanism and the mechanism of the distance encoder are provided. The back adjustment can be performed without causing any influence, and the assembly adjustment of the lens barrel becomes very easy.

[0009]

Next, the present invention will be described in more detail by way of examples. FIG. 1 is a longitudinal sectional view showing one embodiment of the present invention, wherein L1 and L2 are first group lenses for short distance correction,
3, L4 is a second group lens of the master lens, the distance between the first group lens L1, L2 and the second group lens L3, L4 is widened as the shooting distance becomes short, so-called short distance shooting correction .

The first lens group holding frame 1 is provided with a male helicoid 1a on the outer periphery of a middle diameter portion, and is screwed with a female helicoid 2a provided on the inner circumference of the middle diameter portion of the second lens group holding frame 2. ing. At the center of the male helicoid 1a of the first lens group holding frame 1, there is provided a guide groove 1b which is parallel to the optical axis and engages with a connecting lever 8 described later.

The second lens group holding frame 2 holds the second group lenses L3 and L4 in a small diameter portion, and a female helicoid provided on the inner circumference of the intermediate helicoid ring 3 on the outer circumference of the middle diameter portion. A male helicoid 2c screwed with 3a is provided.
A rectilinear groove 2b is provided in the outer periphery of the middle diameter portion of the second lens group holding frame 2 in parallel with the optical axis, and a key member 5 fixed to the fixed cylinder 4 is engaged. Therefore, the second group lens holding frame 2 is configured to be movable in the optical axis direction but not to rotate.

The intermediate helicoid ring 3 is provided at its inner periphery with a female helicoid 3a screwed with the male helicoid 2c of the second lens group holding frame 2, and at the center of the outer periphery at the inner periphery of the fixed cylinder 4. A male helicoid 3b screwed with the female helicoid 4a is provided, and a segment gear 3c is provided on the right outer peripheral portion. A focus ring 6 as a first distance ring is integrally fixed to a left end of the intermediate helicoid ring 3 by a small screw (not shown).

The fixed cylinder 4 has a female helicoid 4a which is screwed with the male helicoid 3b of the intermediate helicoid ring 3 at the left end of the inner peripheral portion. The key member 5 is fixed to the key. A flexible printed board 9 is adhered to an outer peripheral portion of the middle diameter portion 4b of the fixed cylinder 4, and a brush 10 whose surface is fixed to a distance scale ring 7, which is a second distance ring, slides while rotating. It is configured to move and communicate a so-called distance signal to the camera body.

On the large diameter portion 4c of the fixed cylinder 4, a distance scale marked on the outer peripheral portion 7a of the distance scale ring 7 is provided.
A transparent window 11 for viewing through the hole 4e of the fixed cylinder 4.
Has been fixed. Further, a well-known aperture ring 12 is fitted around the outer peripheral portion of the right end of the fixed cylinder 4, and a mount portion for engaging with the camera body is further provided to the right.

In a U-shaped recess between the middle diameter portion 4b and the large diameter portion 4c of the fixed cylinder 4, a distance scale ring 7 is inserted, and the right side of the outer peripheral portion 7a on which the distance scale is scaled. The end face is provided with a notch 7b having a predetermined angle, and the projection 4f of the fixed cylinder 4 is inserted into the notch 7b, so that the distance scale ring 7 has a predetermined angle, that is, the shooting distance is infinite. It is configured to rotate only between and a predetermined close distance.

The key member 5 is fixed to the fixed cylinder 4 and is engaged with a rectilinear groove 2b parallel to the optical axis provided on the outer periphery of the middle diameter portion of the second lens group holding frame 2. The second lens group holding frame 2 is configured to be movable in the optical axis direction but not to rotate.

Since the focus ring 6 is integrally fixed to the left end of the intermediate helicoid ring 3 by a small screw (not shown), when the focus ring 6 is rotated, the intermediate helicoid ring 3 is rotated.

In the distance scale ring 7, a brush 10 for a distance encoder is fixed to an inner peripheral portion, and a distance scale is graduated in an outer peripheral portion 7a. The distance scale ring 7 is inserted into a U-shaped recess between the middle diameter part 4b and the large diameter part 4c of the fixed cylinder 4, and is provided on the right end face of the outer peripheral part 7a on which the distance scale is scaled. Notch 7b having a predetermined angle
Is provided, and the projection 4f of the fixed cylinder 4 is inserted into the notch 7b, so that the distance scale ring 7 rotates only at a predetermined angle, that is, when the shooting distance is between infinity and a predetermined close distance. Is configured.

Further, a left inner diameter portion 7c of the distance scale ring 7 is provided.
Is fitted to the outer diameter portion 6a of the focus ring 6, and when not adhered by the adhesive tape 13, the distance scale ring 7 and the focus ring 6 can be freely rotated. In the case of bonding, the distance scale ring 7 and the focus ring 6 rotate integrally.

A connecting lever 8 is fixed to an inner peripheral portion of the distance scale ring 7, and a distal end 8 a of the connecting lever 8 is provided.
Is engaged with a guide groove 1b provided at the center of the male helicoid 1a of the first lens group holding frame 1 and parallel to the optical axis. For this reason, when the focus ring 6 rotates, the first lens group holding frame 1 also rotates integrally, and the male helicoid 1 a provided on the outer periphery of the middle diameter portion of the first lens group holding frame 1.
By rotating the focusing ring 6 by the action of the female helicoid 2a provided on the inner circumference of the middle diameter portion of the second group lens holding frame 2, the first group lens L1, The distance between L2 and the second lens unit L3, L4 changes, so-called short-range shooting correction is performed.

The connecting lever 8 is fixed to the inner peripheral portion of the distance scale ring 7, and the tip 8 a of the connecting lever 8 is provided at the center of the male helicoid 1 a of the first lens group holding frame 1. When the focus ring 6 rotates, the first lens group 1 also rotates integrally with the guide groove 1b parallel to the optical axis.

As shown in FIG. 2, the flexible printed board 9 is attached to the outer periphery of the middle diameter portion 4b of the fixed cylinder 4, and the brush 10 whose surface is fixed to the distance scale ring 7 rotates. While sliding, the so-called distance signal is communicated to the camera body.

The window 11 is attached to the large-diameter portion 4c of the fixed barrel 4, and is transparent for visually checking the distance scale marked on the outer peripheral portion 7a of the distance scale ring 7 through the hole 4e of the fixed barrel 4. Windows. The aperture ring 12 is rotatably provided at the rear end of the outer periphery of the fixed cylinder 4.

The adhesive tape 13 is a tape for integrally bonding the distance scale ring 7 and the focus ring 6. When the distance scale ring 7 and the focus ring 6 are not bonded, the distance scale ring 7 and the focus ring 6 can freely rotate. However, when they are bonded, the distance scale ring 7 and the focus ring 6 rotate integrally. The rubber ring 14 covers a portion of the distance scale ring 7 and the focus ring 6 adhered by the adhesive tape 13.

Next, the operation of the lens barrel configured as described above will be described. First, a method of taking out the lens barrel back will be described.

In order to carry out the back of the lens, the distance scale ring 7 is rotated in a state where the lens is not adhered by the adhesive tape 13 so that the notch 7b on the right end surface of the outer peripheral portion 7a is infinitely large. Abut the side restrictions. In this state, the brush 10 is located at an infinite position of the encoder pattern on the flexible printed board 9.

At this time, the connecting lever 8 fixed to the inner peripheral portion of the distance scale ring 7 is also located at the infinite position, and the distal end 8a of the connecting lever 8 is connected to the male member of the first lens group holding frame 1. It is engaged with a guide groove 1b provided at the center of the helicoid 1a and parallel to the optical axis.

Here, when the focus ring 6 is rotated, the focus ring 6 is rotated.
Is fixed integrally to the left end of the intermediate helicoid ring 3 with a small screw (not shown), so that rotating the focus ring 6 rotates the intermediate helicoid ring 3. When the intermediate helicoid ring 3 rotates, the male helicoid 2c provided on the outer circumference of the middle diameter portion of the second lens group holding frame 2, the female helicoid 3a provided on the inner circumference of the helicoid ring 3, and the intermediate helicoid ring 3 Male helicoid 3b provided on the outer circumference, female helicoid 4a provided on the inner circumference of fixed barrel 4, key member 5 fixed to fixed barrel 4.
The second group lens holding frame 2 moves in the direction of the optical axis without rotating by the action of and the rectilinear groove 2b provided in the second lens group holding frame 2 and parallel to the optical axis.

At this time, since the connecting lever 8 does not rotate, the first lens group holding frame 1 does not rotate and moves in the optical axis direction by the same amount as the second lens holding frame 2. If the focus ring 6 is rotated and the focus ring 6 and the distance scale ring 7 are integrally fixed with the adhesive tape 13 at a position where the film surface is in focus, the backing-out is completed.

Next, when photographing, when the rubber ring 14 is rotated, the focus ring 6 and the distance scale ring 7 rotate integrally, and the second lens group holding frame 2 does not rotate along the optical axis. To perform focusing.

At the same time, since the distance scale ring 7 also rotates, the connecting lever 8 rotates, and the first group lens holding frame 1 is rotated.
The male helicoid 1a provided on the outer circumference of the middle diameter portion and the female helicoid 2 provided on the inner circumference of the middle diameter portion of the second lens group holding frame 2.
a is screwed, the first group lens holding frame 1 rotates, and the first group lens holding frame 1 moves while rotating along the optical axis in addition to the moving amount of the second group lens holding frame 2. Then, as the shooting distance becomes shorter, the distance between the first group lens L1, L2 and the second group lens group L3, L4 increases, and so-called short-range shooting correction is performed.

[0032]

As described above, according to the present invention, the first distance ring and the second distance ring are integrally fixed after the back ring is adjusted by rotating only the first distance ring. So
Even if the middle helicoid between the double helicoids is rotated and the back of the lens is extended, the back adjustment can be performed without causing any effect on the short distance correction mechanism and the mechanism of the distance encoder. There is an effect that the assembly adjustment of the device becomes very easy.

[Brief description of the drawings]

FIG. 1 is a sectional view showing an embodiment of a lens barrel according to the present invention.

FIG. 2 is a cross-sectional view partially showing a flexible printed board and a brush of the lens barrel according to the embodiment.

[Explanation of symbols]

 L1, L2 First group lens for short distance correction L3, L4 Second group lens 1 First group lens holding frame 2 Second lens group holding frame 3 Intermediate helicoid ring 4 Fixed cylinder 5 Key member 6 Focus ring 7 Distance scale ring Reference Signs List 8 connecting lever 9 flexible printed board 10 brush 11 transparent window 12 aperture ring 13 adhesive tape 14 rubber ring

Claims (1)

(57) [Scope of request for utility model registration] 1. A lens barrel including a short-distance correction mechanism and a distance encoder, a first distance ring integrally fixed to a helicoid intermediate a double helicoid, and a lever engaged with the short-distance correction mechanism. And a second distance ring to which the brush for the distance encoder is fixed and further provided with a rotation limit. After the back distance is adjusted by rotating only the first distance ring, the first distance ring is rotated. A lens barrel, wherein a distance ring and the second distance ring are integrally fixed.