JPH05164954A - Zoom lens barrel - Google Patents

Abstract

PURPOSE:To obtain a small-sized, inexpensive zoom lens barrel which enables zooming operation and focusing operation with the same operation member, provides high optical performance, and guarantees smooth zooming operation. CONSTITUTION:In the zoom lens barrel which has a zoom rectlinear cylinder 8 which is provided outside a fixed part 3, a holding lens barrel 6 for a zoom compensating lens which is provided inside the fixed part 3, a holding lens barrel 5 for a zoom power varying lens which is coupled with the zoom rectlinear cylinder 8 inside the holding lens barrel 6 for the zoom compensating lens, and the operation member 9 which is provided outside the rectlinear cylinder 8 and enables the focusing operation by rotation and the zooming operation by movement along the optical axis, the fixed cylinder 3 and zoom rectlinear cylinder 8 are engaged with each other and the fixed cylinder 3 and the holding lens barrel 6 for the zoom compensating lens are also engaged with each other.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a zoom lens barrel having a variable focal length.

[0002]

2. Description of the Related Art FIG. 4 shows a zoom operation and a focus operation.
FIG. 3 is a vertical cross-sectional view of a zoom lens barrel which is operated by one operation ring, that is, a so-called 1-ring type zoom lens barrel. In FIG. 4, 41a, 41b, 41c and 41d are lenses of a photographing optical system, 41a is a focus lens, 41b is a zoom variable lens, 41c is a zoom correction lens, and 41d is a fixed lens.

Reference numeral 42 is an optical axis, and 43 is a fixed portion of a zoom lens barrel which holds a fixed lens 41d.
And a cam groove 43a for the zoom correction lens 41c and a screw portion 43c. Reference numeral 44 denotes a focus lens barrel, which is a screw portion 44a screwed with the screw portion 43c.
45 is a holding barrel of the zoom variable magnification lens 41b,
Reference numeral 46 denotes a holding barrel of the zoom correction lens 41c, which has a cam groove 46a having a lead.

Reference numeral 47 is a diaphragm unit, and 48 is a screw portion 48a.
And a reference numeral 49 is an operating member, which is a screw groove 49a parallel to the optical axis 42 and a screw portion 49 screwed with the screw portion 48a.
b. 50 is an outer cylinder, 51 is a lens mount, 5
Reference numeral 2 denotes a roller for the zoom correction lens 41c, which is planted equally on the outer surface of the holding barrel 46, and is fitted in the cam groove 43b. Reference numeral 53 denotes a focus roller, which is provided in the focus lens barrel 44, and is fitted in the cam groove 49a. Reference numeral 54 is a roller for the zoom variable magnification lens 41b, in which three rollers are planted equally in the circumferential direction on the inner surface side of the rectilinear barrel 48, and the roller portion 54a has a cam groove 43a and a cam groove 46a.
Is fitted to. A rubber ring 55 covers the operation member 49.

Next, the operation of the zoom lens barrel will be described. First, the focus operation is performed by rotating the operation member 49 around the optical axis. When the operation member 49 rotates, the roller 53 planted in the focus lens barrel 44 is fitted into the cam groove 49a, and the fixed portion 4
Since 3 and the focus lens barrel 44 are screwed together, the focus lens 41a can move in the optical axis direction for focusing. At this time, the screw parts 48a, 49b
Since the screw pitch is much smaller than that of the screw portions 43c and 44a, the operating member 49 moves only slightly in the optical axis direction.

The zoom operation is performed by moving the operation member 49 in the direction of the optical axis 42. When the operating member 49 moves straight in the optical axis direction, the rectilinear barrel 48 moves in the optical axis direction together with the operating member 49. The holding lens barrel 45 of the zoom variable magnification lens 41b is held by a roller 54 implanted in the rectilinear barrel 48, and this roller 54 is fitted into a cam groove 43a parallel to the optical axis 42 of the fixed portion 43. Zoom variable magnification lens 41
b moves in the optical axis direction together with the operating member 49.

At the same time, the cam groove 46a having the lead of the holding lens barrel 46 of the zoom correction lens 41c is fitted in the roller 54, and the roller 52 planted in the holding lens barrel 46 is the cam groove of the fixed portion 43. Since it is fitted in 43b, when the roller 54 moves in the optical axis direction, the zoom correction lens 41c moves in the optical axis direction while rotating.

Further, the cam groove 43b is provided so that the zoom correction lens 41c is located at an appropriate position in accordance with the position of the zoom variable power lens 41b. That is, when the operation member 49 is moved in the optical axis direction, the zoom variable magnification lens 41
b and the zoom correction lens 41c move in the optical axis direction, and zoom operation can be performed. At this time, the focus lens 41a does not move in the optical axis direction.

[0009]

However, in the above-mentioned conventional example, the three rollers 54 are formed in the cam groove 43a and the cam groove 46a.
Since the three rollers 52 are fitted in the cam groove 43b to hold the holding barrel 45 and the holding barrel 46,
As shown in FIG. 4, a gap A is required between the fixed portion 43 and the holding barrel 46, and a gap B is required between the fixed portion 43 and the rectilinear barrel 48. If the gaps A and B are small and are in a fitted state, for example, a zoom operation cannot be performed, or even if it is possible, a large operation torque is required so that the zoom operation cannot be performed in practice. Due to the gaps A and B, the zoom variable magnification lens 41b and the zoom correction lens 41c are moved to the optical axis 4
There is a problem that the optical performance is deteriorated due to eccentricity or inclination with respect to 2.

Further, the lenses 41a, 41b, 41c, 4
Even if the eccentricity or tilt adjustment of 1d is performed to improve the optical performance, it is impossible to improve the optical performance in the entire zoom range because the zoom correction lens 41c is rotated by the zoom operation. It was

Further, from the above problems, in the conventional example, even if the optical system becomes large, the sensitivity of decentering and tilt of the zoom variable magnification lens and the zoom correction lens is reduced.

Further, recently, a high resolution and a low aberration are required for an optical system. If the conventional zoom lens barrel tries to meet these requirements, the zoom lens barrel will become large, or There is a problem that a 1-ring type zoom lens barrel cannot be used in such an optical system.

The present invention solves the above problems, and provides a zoom lens barrel which is compact and ensures high optical performance and smooth zoom operation, and can perform zoom operation and focus operation with the same operating member. With the goal.

[0014]

The present invention is a zoom lens barrel characterized by having the following configuration. (1) A zoom straight-moving barrel provided outside the fixed portion, a holding barrel for a zoom correction lens provided inside the fixed portion,
A holding lens barrel of a zoom variable magnification lens, which is provided inside the holding lens barrel of the zoom correction lens in combination with the zoom rectilinear lens barrel;
In a zoom lens barrel having an operation member which is provided on the outside of the zoom rectilinear barrel to perform a focus operation by rotation and a zoom operation by movement in the optical axis direction, the fixed barrel and the zoom rectilinear barrel are fitted together, and By fitting the fixed barrel and the holding barrel of the zoom correction lens, compared to the conventional 1-ring zoom type lens barrel,
Compact size, high optical performance can be guaranteed, and smooth zoom operation can be performed. (2) One of two coupling portions of the plurality of coupling portions of the zoom straight-moving barrel and the holding barrel of the zoom variable power lens, or one of two coupling portions.
One part provided in the holding lens barrel of the zoom correction lens, and the portion is roller-shaped, and the roller is fitted to the cam provided in the fixed part and the cam provided in the holding lens barrel of the zoom correction lens Alternatively, since the two rollers are fitted to the correction cam provided on the fixed portion, it is possible to obtain a one-ring type zoom lens barrel capable of performing a smooth zoom operation.

[0015]

【Example】

First Embodiment FIGS. 1 to 3 show a first embodiment of the present invention. FIG. 1 is a longitudinal sectional view of a zoom lens barrel which best shows the features of the present invention. FIGS. 2 and 3 are zoom lens barrels. It is a principal part perspective view of FIG.

1 to 3, 1a, 1b, 1
Reference numerals c and 1d are lenses of a photographing optical system, 1a is a focus lens, 1b is a zoom variable magnification lens, 1c is a zoom correction lens, and 1d is a fixed lens.

Reference numeral 2 is an optical axis, 3 is a fixed portion of a zoom lens barrel holding a fixed lens 1d, and a cam groove 3a parallel to the optical axis 2, a cam groove 3b for the zoom correction lens 1c, and a screw portion 3c. Have. The three cam grooves 3a are evenly provided in the circumferential direction, and two of the three cam grooves 3a have a wider groove width than the other one cam groove 3a '. Two cam grooves 3b are evenly provided in the circumferential direction.

Reference numeral 4 denotes a focus lens barrel, which has a screw portion 4a screwed into the screw portion 3c. Reference numeral 5 is a holding barrel of the zoom variable magnification lens 1b, 6 is a holding barrel of the zoom correction lens 1c, a part of the outer surface of which is fitted to the fixed portion 3, and which has a cam groove 6a having a lead. The three cam grooves 6a are evenly provided in the circumferential direction, and two of the three cam grooves 6a are wider than the other one cam groove 6a '.

Reference numeral 7 is a diaphragm unit, and 8 is a straight advancing cylinder having a screw portion 8a, and a part of the inner surface thereof is fitted with the fixing portion 3. Reference numeral 9 denotes an operating member, which is a cam groove 9a parallel to the optical axis 2.
And a screw portion 9b screwed with the screw portion 8a. The two cam grooves 9a are evenly provided in the circumferential direction. 1
Reference numeral 0 is an outer cylinder, 11 is a lens mount, and 12 is a roller for the zoom correction lens 1c. Two rollers are equally spaced in the circumferential direction on the outer surface of the holding barrel 6, and at least one roller 1 is provided.
2 is fitted in the cam groove 3b.

Reference numeral 13 is a focusing roller, and two rollers 13 are equally planted in the circumferential direction on the outer surface of the focus lens barrel 4. At least one roller 13 is fitted in the cam groove 9a. .. Reference numeral 14 denotes a roller for the zoom variable power lens 1b having the shape shown in FIG. 3, and three rollers are equally planted in the circumferential direction of the inner surface of the rectilinear barrel 8. The portion 14a is fitted in the cam groove 3a 'and the cam groove 6a'.

Further, the remaining two rollers 14 are not fitted into the cam grooves 3a, 6a because the corresponding cam grooves 3a and 6a have a wide groove width. Reference numeral 15 is a rubber ring that covers the operation ring 9, 16 is a screw for fixing the roller 12 to the holding barrel 6, and 17 is a screw for fixing the roller 14 to the rectilinear barrel 8.

Next, the operation of the zoom lens barrel in the first embodiment will be described. First, the focus operation is performed by rotating the operation member 9 around the optical axis. When the operation member 9 rotates, the roller 13 planted in the focus lens barrel 4 is fitted into the cam groove 9a, and the fixing portion 3 and the focus lens barrel 4 are screwed together, so that the focus lens 1a can move in the direction of the optical axis for focusing. At this time, the screw parts 8a, 9
Since the screw pitch of b is much smaller than that of the screw portions 3c and 4a, the operating member 9 moves only slightly in the optical axis direction.

In the case of zoom operation, the operation member 9 is moved to the optical axis 2
By moving in the direction of. When the operating member 9 moves straight in the optical axis direction, the straight-moving barrel 8 fitted with the fixed portion 3 moves in the optical axis direction together with the operating member 9. The holding lens barrel 5 of the zoom variable power lens 1b is held by a roller 14 that is planted in the rectilinear barrel 8, and one roller portion 14 of the rollers 14 is used.
Since a is fitted in the cam groove 3a ′ parallel to the optical axis 2 of the fixed portion 3, the zoom variable lens 1b moves in the optical axis direction together with the operating member 9.

At the same time, the cam groove 6a 'having a narrow groove width having the lead of the holding barrel 6 of the zoom correction lens 1c is formed by the roller 1
4 is fitted in the roller portion 14a and the roller 12 planted in the holding barrel 6 is fitted in the cam groove 3b of the fixed portion 3. Therefore, when the roller 14 moves in the optical axis direction, the zoom The correction lens 1c moves in the optical axis direction while rotating.

Further, the cam groove 3b is provided so that the zoom correction lens 1c is located at an appropriate position according to the position of the zoom variable power lens 1b. That is, the operating member 9
Is moved in the optical axis direction, the zoom variable lens 1b and the zoom correction lens 1c are moved in the optical axis direction, and zoom operation can be performed. At this time, the focus lens 1a does not move in the optical axis direction.

As described above, the holding barrel 6 and the fixed portion 3 and the fixed portion 3 and the rectilinear barrel 8 are fitted, but the cam groove 3a 'of the fixed portion 3 and the cam groove 6a' of the holding barrel 6 are fitted. Since it is used only, it is possible to maintain a smooth zoom operation and reduce the eccentricity and inclination of the zoom variable magnification lens 1b and the zoom correction lens 1c with respect to the optical axis 2.

Since two rollers 12 and two rollers 13 are used, at least one roller 12,
At least one of the rollers 13 is adjusted and attached so as to absorb the equal difference between the cam groove 3b and the cam groove 9a. Second Embodiment In this embodiment, the width of each of the cam groove 3a and the cam groove 6a is narrowed by one (3a ', 6a'), but the roller 14 is adjusted and mounted. If so, at least one of the narrow cam grooves 3a ′ and 6a ′ has two narrow cam groove width cams, and the cam groove 3 is provided at two locations.
The rollers 14a and 6a may be fitted together. Further, the phases of the cam grooves 3a 'and 6a' may be the same or different, and the cam groove 3a, the cam groove 6a and the roller 14 corresponding thereto may be provided.
Can be any number.

Further, in this embodiment, the cam groove 3
The widths of the cam grooves other than a ′ and 6a ′ are widened so that the rollers 14 are not fitted to each other. However, the cam groove widths of the cam grooves 3a and 6a are constant, and The diameter of 14a may be reduced so that the rollers 14a are not fitted in the cam grooves 3a and 6a, and the rollers 14a are fitted in the cam grooves 3a and 6b. In this way, the cam groove 3
The portions where a and 6b and the roller 14 are not fitted may be configured by any means.

In this embodiment, the cam groove 3b and the cam groove 3b are also included.
Each of the rollers 12 corresponding to 2 is composed of two rollers, but this may be one, or the cam groove 9a and the roller 13 corresponding to the cam groove 9a are also composed of two rollers. You may comprise one by one.

[0030]

As described above, the holding lens barrel of the zoom correction lens is fitted to the fixed portion of the zoom lens barrel, and the fixed portion of the zoom lens barrel is fitted to the rectilinear barrel. Therefore, it is possible to reduce the eccentricity and tilt of the zoom variable power lens and the zoom correction lens, and obtain a 1-ring type zoom lens barrel having high optical performance.

Further, in the above-mentioned one-ring type zoom lens barrel, one or two of the coupling members of the holding lens barrel of the zoom variable magnification lens and the rectilinear barrel are cam grooves of a fixed portion parallel to the optical axis. Also, one or two rollers fitted to the cam groove having the lead of the holding lens barrel of the zoom correction lens and planted in the holding lens barrel of the zoom correction lens are fitted to the correction cam of the fixed portion. Therefore, there is an effect that a 1-ring type zoom lens barrel capable of performing a smooth zoom operation can be obtained.

[Brief description of drawings]

FIG. 1 is a vertical sectional view of a zoom lens barrel showing a first embodiment of the present invention.

FIG. 2 is a perspective view of a main part of the zoom lens barrel in the first embodiment.

FIG. 3 is a perspective view of a main part of the zoom lens barrel in the first embodiment.

FIG. 4 is a vertical sectional view of a conventional zoom lens barrel.

[Explanation of symbols]

 3 Fixed part 5 Holding lens barrel for zoom variable magnification lens 6 Holding lens barrel for zoom correction lens 8 Zoom rectilinear barrel 9 Operation member 12 Roller 14 Roller 3a, 3b Cam groove (cam) 6a Cam groove (cam)

Claims (2)

[Claims] 1. A zoom rectilinear barrel provided outside the fixed part,
A holding lens barrel for a zoom correction lens provided inside the fixed portion, and a holding lens barrel for a zoom variable magnification lens provided inside the holding lens barrel for the zoom correction lens in combination with the zoom rectilinear barrel; In a zoom lens barrel having an operation member which is provided on the outside of a zoom rectilinear barrel to perform a focus operation by rotation and a zoom operation by movement in the optical axis direction, the fixed barrel and the zoom rectilinear barrel are fitted together, and A zoom lens barrel characterized in that a fixed barrel and a holding barrel of the zoom correction lens are fitted together. 2. A part of one or two connecting parts of a plurality of connecting parts of the zoom rectilinear barrel and the holding barrel of the zoom variable magnification lens has a roller shape, and this roller is the fixed part. A correction cam that is fitted to the provided cam and the cam provided on the holding barrel of the zoom correction lens, and one or two rollers provided on the holding barrel of the zoom correction lens are provided on the fixed portion. The zoom lens barrel according to claim 1, characterized in that the zoom lens barrel is fitted in.