Optical: systems and elements – Compound lens system – Telescope
Reexamination Certificate
2000-10-31
2001-10-23
Spyrou, Cassandra (Department: 2872)
Optical: systems and elements
Compound lens system
Telescope
C359S418000
Reexamination Certificate
active
06307673
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to a focusing device of a binocular in which an interpupillary adjustment is carried out by a biaxial interlock mechanism.
2. Description of the Related Art
Conventionally, a binocular is provided with an interpupillary adjustment function. The distance between the eyes of different users of binocular varies, by carrying out the interpupillary adjustment function, a distance between optical axes of a pair of eyepieces can be adjusted to suit the distance between the eyes of any user. There is a biaxial type binocular, as a binocular having the interpupillary adjustment function.
In the biaxial type binocular, telescopic optical stems have respective Porro prisms as erector prismatic systems, respective objective optical systems and respective eyepieces whose optical axes are displaced out of alignment with those of the objective optical systems. Each of a pair of eyepieces and Porro prisms are respectively rotated around an optical axis of a corresponding objective optical system of a pair of objective optical systems, and the rotations of the eyepieces are interlocked. Namely, there are two axes of rotation of the eyepieces to adjust the distance between the optical axes of the eyepieces.
On the other hand, the biaxial type binocular also has a focusing function. The focusing function is carried out by moving any optical systems of the telescopic optical systems along optical axes of the telescopic optical systems, so that an object image, formed by the objective optical systems, is brought into focus. As the eyepieces are rotatably held for the interpupillary adjustment in the above-mentioned biaxial type binocular, the focusing function is generally performed by moving the objective optical systems.
If other functions, for example a zooming and a focused image tremble correcting function, are added to the biaxial type binocular, it is advantageous that other optical systems for these other functions are situated close to the objective optical systems. It is then possible to share the same elements in order to perform different functions and to save weight and space in the binocular.
However, in the biaxial type binocular, a focusing assembly, by which the objective optical systems are held and moved along the optical axes thereof, is disposed close to the objective optical systems. Namely, it becomes difficult to unitarily install the other optical systems close to the objective optical systems, without causing enlargement of the binocular.
SUMMARY OF THE INVENTION
Therefore, an object of the present invention is to provide a focusing device which can be applied to various types of biaxial binocular.
In accordance with an aspect of the present invention, there is provided a focusing device for a biaxial type binocular. The biaxial type binocular comprises: a pair of telescopic optical systems including a pair of objective optical systems and a pair of eyepieces; and a supporting member which fixedly holds the pair of objective optical systems and rotatably supports a pair of eyepiece units including a pair of eyepiece holding portions which hold the pair of eyepieces such that eyepiece optical axes of the pair of eyepiece optical systems are parallel to objective optical axes of the pair of objective optical systems and the pair of eyepieces are rotatable around the objective optical axes.
The focusing device comprises: a connecting member that connects the pair of eyepiece holding portions; and a driving assembly that drives the connecting member in a direction parallel to the eyepiece optical axes.
Preferably, the driving assembly comprises: a driving shaft that is threadably engaged with the connecting member, is rotatable around an axis thereof which is parallel to the eyepiece optical axes, and is fixed in the parallel direction; and a rotation preventing member that prevents a rotational movement of the driving shaft from being transmitted to the connecting member.
Preferably, the rotation preventing member is a bar-shaped member, the longitudinal direction of which extends along the driving shaft that passes through the connecting member. The rotation preventing member guides movement of the connecting member in the parallel direction.
Further, preferably, the connecting member comprises: a first supporting portion that supports the rotation preventing member; a second supporting portion with which the driving shaft is thredably engaged; a pair of third supporting portions that supports the pair of eyepiece holding portions; a first connecting portion that connects the first supporting portion and one of the pair of third supporting portions; a second connecting portion that connects the first supporting portion and another of the pair of third supporting portions; and a third connecting portion that connects the second supporting portion and the first supporting portion.
Optionally, a length of the third connecting portion along the longitudinal direction thereof is shorter than length of the first connecting portion and the second connecting portion along the longitudinal directions thereof.
The first connecting portion, the second connecting portion and the third connecting portion radially extend from the first supporting portion.
Optionally, a length of the third connecting portion along the longitudinal direction thereof is longer than length of the first connecting portion and the second connecting portion along the longitudinal directions thereof.
Preferably, in the supporting member, an objective supporting portion which supports the objective optical systems and an eyepiece supporting portion which supports the eyepiece units are unitarily formed, and the driving shaft and the rotation preventing member are respectively supported by bearings which are formed in the supporting member.
Preferably, in the pair of telescopic optical systems, movable optical systems are positioned between the pair of objective optical system and a pair of optical inversion systems.
Optionally, the movable optical systems are correction optical systems for correcting a focused image tremble, and driving devices that drive the correction optical systems are disposed between the pair of objective optical systems and the pair of optical inversion systems.
According to the present invention, the connecting member connects the pair of eyepiece holding portions, and the connecting member is able to move along the optical axes of the eyepieces. In the binocular according to the present invention, the interpupillary adjustment of biaxial type can be performed by rotating the eyepieces and the focusing can be carried out by moving the eyepieces along the optical axes thereof.
As described above, in the binocular according to the present invention, the focusing is carried out by moving the eyepieces. As eyepieces are generally lighter than objective optical systems, a driving apparatus of the eyepieces can be simpler than a driving apparatus of the objective optical systems. Therefore, it is possible to downsize the focusing device in the binocular, according to the present invention.
If the third connecting portion is shorter than the first and second connecting portions in the connecting member, a space exists below the first supporting portion, namely between the first and second connecting portions. Accordingly, other members of the binocular are able to be positioned in this space so that the binocular becomes compact.
If the third connecting portion is longer than the first and second connecting portions in the connecting member, a distance between the first and second supporting portions is relatively large. Namely, there is a relatively long distance between the rotation preventing member and the driving shaft so that when the connecting member is moved along the optical axes of the eyepieces for focusing, the movement is guided by the rotation preventing member with increased stability.
BRIEF DESCRIPTION OF THE DRAWINGS
REFERENCES:
patent: 2534776 (1950-12-01), Kershaw et al.
patent: 5583693 (1996-12-0
Denpo Atsushi
Hirunuma Ken
Tsukamoto Shinji
Asahi Kogaku Kogyo Kabushiki Kaisha
Greenblum & Bernstein P.L.C.
Spyrou Cassandra
Treas Jared
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