JPH08110550A - Visibility adjusting mechanism for zoom finder - Google Patents

Abstract

PURPOSE: To suppress manufacturing costs by simplifying the constitution of a visibility adjusting mechanism for a zoom finder and its assembling process. CONSTITUTION: A guiding shaft 74 is fitted to a housing 22 and a first lens frame 71 on which a first lens group 13a is fixed and a third lens frame 73 on which a third lens group 13c is fixed are fitted to the guiding shaft 74. A coil spring 76 is provided between the first and second lens frames 71 and 73 of the guiding shaft 74. An adjusting machine screw 81 is screwed into the screw hole 22k of the housing 22. The first lens frame 71 is energized in a direction opposite to the third lens frame 73 by the coil spring 76 and abutted on the point of the adjusting machine screw 81. It is rotated so that the position in the optical axial direction of the first lens frame 71 is finely adjusted to adjust the visibility.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a real image type zoom finder provided in, for example, a compact camera, and more particularly to a diopter adjusting mechanism of the zoom finder.

[0002]

2. Description of the Related Art Conventionally, as an example of a zoom finder,
There is a configuration in which the first lens group is fixed to the housing, the second and third lens groups are arranged behind the first lens group, and the lens group is movable along the optical axis. That is, the zooming operation is performed by displacing the second and third lens groups in the optical axis direction. In order to adjust the diopter of the finder optical system as described above, the first lens group includes the second and third lens groups.
It is configured to be displaceable within a predetermined range with respect to the lens group, and in the assembly process of the zoom finder,
The second and third lens groups are finely adjusted in the optical axis direction while being fixed at a predetermined position, and fixed at a predetermined position. For this reason, the housing has, for example, an adjusting mechanism having a guide member for movably supporting the first lens group, a stopper with which the first lens group abuts, and an urging member for urging the first lens group toward the stopper. Is provided.

[0003]

However, such an adjusting mechanism for the first lens group has a complicated structure, which not only complicates the assembly of the finder but also raises the manufacturing cost. .

An object of the present invention is to simplify the structure of the diopter adjustment mechanism of the zoom finder, simplify the assembling process of the zoom finder, and reduce the manufacturing cost.

[0005]

A diopter adjusting mechanism of a zoom finder according to the present invention includes a housing for housing a fixed lens and a movable lens, and a housing provided in the housing. The fixed lens and the movable lens both have an optical axis. Along with a guide member for displaceably supporting the movable lens, a zooming means for performing a zooming operation by displacing the movable lens along the optical axis in a state where the fixed lens is stationary, It is characterized in that it comprises an urging means for urging and an adjusting member for finely adjusting the fixed position of the fixed lens on the guide member.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to illustrated embodiments. FIG. 1 is a front view of a compact camera including a viewfinder diopter adjustment mechanism according to an embodiment of the present invention.

A photographing optical system 12 is provided substantially in the center of the front of the camera body 11, and directly above the photographing optical system 12.
A finder objective optical system 13 is provided. A strobe 14 is provided on the upper right portion of the front of the camera body 11.

FIG. 2 is a view of the arrangement of optical components constituting the finder optical system as seen from above. In the middle of the optical path between the objective optical system 13 and the eyepiece optical system 17, the roof mirror 21
A condenser lens 18, a pentaprism 19 and a focusing plate 20 are provided. The objective optical system 13 includes
It has a third lens group 13a, 13b, 13c. The first lens group 13a is a fixed lens that is always stationary when the camera is in use.
Reference numerals b and 13c are movable lenses that can be displaced in the optical axis direction.
That is, the finder zooming operation is performed by displacing the second lens group 13b and the third lens group 13c in the optical axis direction.

The roof mirror 21, that is, the erecting optical system is the third
The objective optical system 1 is arranged behind the lens group 13c.
The light ray passing through 3 is reflected by the Dach mirror 21,
As a result, the subject image is converted into an erect image. The light rays reflected by the roof mirror 21 are condensed by the condenser lens 18 and a subject image is formed on the focusing plate 20. This subject image is reflected by the pentaprism 19 and observed through the eyepiece optical system 17.

FIG. 3 is an exploded perspective view of the zoom finder. The objective optical system 13 is housed in the first housing portion 23 formed on the left side of the center of the housing 22 when viewed from the front (lower left side in FIG. 3). Eyepiece optical system 17
Is a second housing portion 2 formed on the rear side of the housing 22.
It is housed in 4. The penta prism 19 has a second housing portion 24.
It is housed in the third housing portion 25 formed on the front side of the. The roof mirror 21 is housed in the fourth housing portion 26 formed behind the first housing portion 23 and on the side of the third housing portion 25.

The first, second and third lens groups 13a, 1
3b and 13c are fixed to the first, second and third lens frames 71, 72 and 73, respectively. The first guide shaft 74 has a hole 22 formed in the front end portion of the housing 22.
i and a hole (not shown) formed inside,
The second guide shaft 75 is attached to a hole 22j formed on the side of the hole 22i and a hole (not shown) formed inside the housing 22. That is, these guide shafts 74, 75 extend horizontally and are parallel to each other. First, second and third lens frames 71, 72, 7
Support holes 71a, 72a, and 73a are formed in each of the holes 3. The support holes 71a and 73a are fitted to the first guide shaft 74, and the support holes 72a are fitted to the second guide shaft 75. Thereby, each lens group 13a, 13
b and 13c can be displaced along the optical axis.

A coil spring 76 is provided on the first guide shaft 74. One end of the coil spring 76 contacts the first lens frame 71, and the other end contacts the third lens frame 73. Therefore, the third lens group 13c is always urged in the direction away from the first lens group 13a. A coil spring 77 is also provided on the second guide shaft 75, and one end of the coil spring 77 contacts the second lens frame 72.
The other end contacts a wall surface (not shown) of the housing 22. Therefore, the second lens group 13b is always biased toward the first lens group 13a.

The second and third lens frames 72, 73 include
Cam pins 78 and 79 projecting downward are attached, respectively. These cam pins 78 and 79 are engaged with cam holes formed in a cam plate described later. On the other hand, the screw hole 22 formed in the portion of the housing 22 adjacent to the hole 22i
Adjustment screw 81 is screwed into k, and adjustment screw 8
The front end portion of the No. 1 projects into the housing 22 and contacts the end surface 71 b of the first lens frame 71. That is, the second and third lens frames 72 and 73 are set at positions according to the shape of the cam hole described later, and the first lens frame 71 is attached to the coil spring 76 provided between the second lens frame 72 and the third lens frame 73. It is biased and fixed at the position where it abuts the adjusting screw 81. The fixing position of the first lens group 13a on the guide shaft 74 is finely adjusted by rotating the adjusting screw 81 and changing the amount of protrusion into the housing 22.

On the lower surface of the housing 22, screws 82, 8
The guide plate 85 is attached by 3, 84. A cam plate 86 is attached to the lower surface of the guide plate 85.
The cam plate 86 is formed with a guide hole 86a extending linearly in a direction orthogonal to the optical axes of the lens groups 13a to 13c, and the guide hole 86a has a pair of guide pins 87 fixed to the guide plate 85. , 88 are engaged. That is, the cam plate 86 can be displaced in a direction that is significantly behind the optical axis.
Further, the cam plate 86 is formed with first and second cam holes 86b and 86c extending in a direction inclined with respect to the guide hole 86a. The second lens frame 72 is provided in the first cam hole 86b.
The cam pin 78 of the second cam hole 78c is engaged, and the third cam hole is inserted into the second cam hole 86c.
The cam pin 79 of the lens frame 73 is engaged. Therefore, when the cam plate 86 is displaced, the cam pins 78 and 79, that is, the second lens group 13 are held with the first lens group 71a stationary.
b and the third lens group 13c are displaced along the optical axis, and the zooming operation is performed.

As described above, in the present embodiment, the first lens group 13a is supported by the guide shaft 74 that supports the third lens group 13c so as to be displaceable in the optical axis direction, and the third lens group 13c is supported by the optical axis. The first lens group 13a is biased toward the adjustment screw 81 by the coil spring 76 that biases in the direction,
A diopter adjustment mechanism of the zoom finder is configured. That is, in this embodiment, the third lens group 1 which is a variable power lens
A part of the mechanism for supporting 3a also serves as a mechanism for slightly displacing the first lens group 13a. Therefore the first
Since the structure of the adjusting mechanism of the lens group 13a is simple and the number of parts is reduced, the zoom finder can be easily assembled and the manufacturing cost thereof can be suppressed.

The first lens group 13a may be attached to the second guide shaft 76 instead of the first guide shaft 74.

The present invention can also be applied to a zoom finder in which the third lens group 13a is not provided and only the second lens group 13b is a variable power lens.

[0018]

As described above, according to the present invention, the structure of the diopter adjusting mechanism of the zoom finder is simplified and
It is possible to simplify the assembly process of the zoom finder and reduce its manufacturing cost.

[Brief description of drawings]

FIG. 1 is a front view of a compact camera including a diopter adjustment mechanism of a zoom finder that is an embodiment of the present invention.

FIG. 2 is a view of the arrangement of optical components forming the finder optical system as seen from above.

FIG. 3 is a perspective view showing an exploded view of a zoom finder.

[Explanation of symbols]

 13a First lens group (fixed lens) 13c Third lens group (movable lens) 22 Housing 74 Guide shaft (guide member) 76 Coil spring (biasing member) 81 Adjustment screw (adjusting member) 86 Cam plate (zooming means)

Claims (5)

[Claims] 1. A housing for accommodating a fixed lens and a movable lens, a guide member provided in the housing for supporting both the fixed lens and the movable lens so as to be displaceable along an optical axis, and the fixed lens. Zooming means for performing a zooming operation by displacing the movable lens along the optical axis in a stationary state, urging means for urging the movable lens in a direction away from the fixed lens, and the guide of the fixed lens. A diopter adjusting mechanism for a zoom finder, comprising: an adjusting member for finely adjusting a fixed position on the member. 2. The zoom finder according to claim 1, wherein the urging means urges the fixed lens or a lens frame to which the fixed lens is attached in a direction of abutting on the adjusting member. Diopter adjustment mechanism. 3. The fixed lens is a first lens group arranged near the front end of the housing, and the movable lens is another lens group arranged behind the first lens group. The diopter adjustment mechanism of the zoom finder according to claim 1. 4. The diopter adjustment mechanism of the zoom finder according to claim 2, wherein the guide member is a guide shaft attached to the housing and extending in the horizontal direction. 5. The diopter adjusting mechanism of a zoom finder according to claim 1, wherein the adjusting member is an adjusting screw screwed into a housing.