Binoculars

Providing a pair of binoculars that is able to prevent diopter from being changed after adjusting diopter difference by pushing down the focus knob after adjusting diopter difference so as not to touch the operating knob, and able to prevent the focus position from being changed after adjusting focus position by pulling out the focus knob to create a focus lock state after adjusting focus position.

TECHNICAL FIELD

The present invention relates to a pair of binoculars.

BACKGROUND ART

Generally, a pair of binoculars includes various adjustment mechanisms such as a focusing mechanism, a diopter adjustment mechanism in addition to a pair of right and left lens barrels each including a telescopic optical system. With the diopter adjustment mechanism, diopter difference between right and left eyes of a user is adjusted. With this state, the user carries out focusing right and left telescopic optical systems by the focusing mechanism. After adjusting right and left diopter difference, even if the object to be observed is changed, the user can observe the object by just carrying out focusing unless the user is changed.

When the object to be observed is a fixed point locating near to infinity, or when the object to be observed is locating far away so as to be able to focus the object by means of accommodation of the user's eyes, the object is preferably observed by a fixed focus depending upon accommodation of naked eye or depth of field. Moreover, after adjusting focus, it is preferable that focusing is fixed, as a matter of course, during observation, and even in a state that a distance to the object is not near to infinity (see Japanese Utility Model Publication No. 2592717).

However, when an operation portion of the diopter adjustment mechanism that has already been adjusted is touched by mistake during observation, there is a danger that diopter difference goes wrong. When diopter difference goes wrong, diopter difference of right and left eyes has to be adjusted again, so that the observation has to be interrupted. Moreover, when the operation portion of the focusing mechanism is touched upon using binoculars, focus position may be changed.

DISCLOSURE OF THE INVENTION

The present invention is made in view of the aforementioned problems, and a first object of the present invention is to provide a pair of binoculars capable of preventing diopter difference from changing after adjusting diopter difference. A second object of the present invention is to provide a pair of binoculars capable of preventing focus position from changing after carrying out focusing.

In order to realize the aforementioned object, the first invention includes: a pair of lens barrels each holding a telescopic optical system including a focusing lens; a diopter adjusting mechanism that adjusts diopter difference of one of the telescopic optical systems with respect to the other of the telescopic optical systems by moving the focusing lens of the one of the telescopic optical systems along an optical axis of the one of the telescopic optical systems; a diopter adjustment wheel that moves the focusing lens of the one of the telescopic optical systems along the optical axis by operating the diopter adjusting mechanism by a rotational operation; and a diopter-adjustment-operation-preventing member that makes the diopter adjustment wheel either operable or inoperable.

The first invention makes it possible to prevent diopter difference from being changed after adjusting diopter difference.

The second invention includes: a pair of lens barrels each holding a telescopic optical system including a focusing lens; a focusing mechanism that moves both of the focusing lenses held by the pair of lens barrels, respectively, along the respective optical axes; a focusing operation portion that moves both of the pair of focusing lenses along respective optical axes by operating the focusing mechanism by a rotational operation; and a focus-position-change-preventing member that prevents a focus position of the telescopic optical system determined by the focusing mechanism from being changed.

The second invention makes it possible to prevent the focus position from being changed after adjusting focus position.

THE EMBODIMENT FOR CARRYING OUT THE INVENTION

An embodiment of the present invention is explained with reference to accompanying drawings.

FIG. 1is a partially cross-sectional view showing a pair of binoculars according to an embodiment of the present invention.FIG. 2is a partially enlarged view ofFIG. 1.FIG. 3is a side view showing a male lead ring seen from an internal gear side.FIG. 4is a side view showing a focus knob seen from a spur gear side.FIG. 5is a cross-sectional view of a pair of binoculars.FIG. 1shows a state where the focus knob40is pushed down,FIG. 2shows a state where the focus knob40is pulled up, andFIG. 5shows a state where the focus knob40is located at an intermediate position.

In the following explanation, “left” and “right” denote when the binoculars are seen from the eyepiece side. InFIGS. 1,2,5, the eyepiece side comes lower side of each figure, and the objective lens side comes upper side of each figure.

The pair of binoculars includes a pair of lens barrels10,20each of which a telescopic optical system is held therein, and a bridge portion30that is extended from both of the lens barrels10,20and connects both of the lens barrels10,20. In the bridge portion30, there are provided a diopter adjustment mechanism and a focusing mechanism described below. The diopter adjustment mechanism and the focusing mechanism are operated by a diopter adjustment wheel53and a focus operation portion, respectively.

The bridge portion30is composed of bridge members30a,30bintegrally provided to respective lens barrels10,20, and a first intermediate tube31that is located between both lens barrels10,20and positioned parallel to both lens barrels10,20. The bridge members30a,30bare formed, respectively, with holes (not shown) in respective directions of optical axes L1, L2of the telescopic optical systems. The first intermediate tube31is inserted into the holes such that these holes lie in a row on the same axis. The bridge members30aand30bare connected in this manner through the first intermediate tube31, and rotatable by a given angle centering on the first intermediate tube31. Accordingly, by rotating a pair of lens barrels10,20centering on an axis MA of the first intermediate tube31, it becomes possible to adjust interpupillary distance.

The right lens barrel10holds the objective lens (not shown) disposed upside ofFIG. 1, the eyepiece (not shown) disposed downside ofFIG. 1, and a focusing lens11and an erecting prism12on the optical path between the objective lens and the eyepiece. The telescopic optical system is composed of the objective lens (not shown), the focusing lens11, the erecting prism12, and the eyepiece (not shown).

The left lens barrel20holds the objective lens (not shown) disposed upside ofFIG. 1, the eyepiece (not shown) disposed downside ofFIG. 1, and a focusing lens21and an erecting prism (not shown) on the optical path between the objective lens and the eyepiece. The telescopic optical system is composed of the objective lens (not shown), the focusing lens21, the erecting prism (not shown), and the eyepiece (not shown).

A focusing lens frame13for holding the focusing lens11in the lens barrel10is connected to a right first focusing rod51disposed between the optical axis L1of the telescopic optical system and the axis MA parallel to the optical axis L1through a connecting pin14, a focusing lens frame13for holding the focusing lens21in the lens barrel20is connected to a left first focusing rod51through a connecting pin14in the same manner.

The first focusing rod51is movable along an axis FA which is an axis (herein after called “a focusing axis”) of the first focusing rod51(seeFIG. 2), but not rotatable centering on the focusing axis FA. The focusing axis FA is parallel to the optical axes L1, L2. A female screw51acapable of being screwed from the eyepiece side is formed on the first focusing rod51. A second focusing rod52is disposed to the eyepiece side of the first focusing rod51on the same axis of the focusing axis FA. A male screw52ais formed on the objective lens side tip of the second focusing rod52. The male screw52aof the second focusing rod52is rotatably screwed to the female screw51aof the first focusing rod51.

The diopter adjustment wheel53for operating diopter adjustment mechanism is provided outside of both of the right and left second focusing rods52,52centering on the axis MA. The diopter adjustment wheel53is composed of an operating portion main body53chaving a cylindrical shape, and an operating knob53bprovided on one end of the main body53c. An internal gear53ais formed on internal circumference of the operating portion main body53c.

A step portion is formed on the internal circumference of the operating knob53b. An outer edge of a flat plate59having a disk shape is fitted to the step portion. The flat plate59is put between a second intermediate tube57and a locking projection57dtogether with a male lead ring55, and restricted movement along the optical axis. With this fitting, the operating knob53bis rotatable centering on the axis MA along the outer edge of the flat plate59as a guide, but restricted movement along the optical axis to the objective lens side.

The eyepiece side tip of the operating portion main body53cis fitted to a brim portion55aformed on the outer edge of the eyepiece side tip of the male lead ring55explained later. With this fitting, the operating portion main body53cis rotatable centering on the axis MA along the outer edge of the brim portion55aof the male lead ring55, but restricted movement along the optical axis to the eyepiece side.

With this configuration, the diopter adjustment wheel53is rotatable centering on the axis MA, but not movable in the optical axis direction L1, L2.

A gear52bis formed in the circumferential direction on the eyepiece side tip of the right second focusing rod52. The gear52bis meshed with the internal gear53aformed on the operating portion main body53cof the diopter adjustment wheel53. With this configuration, the right second focusing rod52is rotatable centering on the focusing axis FA together with the rotation of the diopter adjustment wheel53.

By rotating the right second focusing rod52, screwed depth of the right second focusing rod52with respect to the right first focusing rod51varies, so that relative distance in the optical axis direction L1, L2adding the right first focusing rod51and the right second focusing rod52varies. Accordingly, relative positions in the optical axis direction L1, L2of the right focusing lens frame13, and the right first focusing rod51with respect to the position of the right second focusing rod52are determined in accordance with the screwed depth of the right second focusing rod52with respect to the right first focusing rod51. The diopter adjustment mechanism is composed of the right second focusing rod52, the right first focusing rod51, the right connecting pin14and focusing lens13.

On the eyepiece side tip of the left second focusing rod52, a gear corresponding to the gear52is not formed. Accordingly, the left second focusing rod52is not meshed with the internal gear53aformed on the inner circumference of the diopter adjustment wheel53.

A female lead ring54is disposed inside of the right and left second focusing rods52,52centering on the axis MA. A projection54aprojecting in a direction perpendicular to the axis MA is formed on the outer circumference of the female lead ring54. The male lead ring55is disposed inside of the female lead ring54centering on the axis MA. The second intermediate tube57is disposed inside of the male lead ring55centering on the axis MA.

The second intermediate tube57is disposed to the eyepiece side of the first intermediate tube31that connects the bridge members30a,30b. The objective lens side tip of the second intermediate tube57protrudes in the axis MA direction, and a screw57bscrewing into the inner circumference of the first intermediate tube31is formed thereon. A protruding portion57cprotruding in a direction perpendicular to the axis MA and having step portions whose diameter becomes smaller toward the eyepiece direction is formed on the outer circumference of the objective lens side of the second intermediate tube57.

The second intermediate tube57is restricted in movement in the optical axis direction L1, L2by screwing the screw31aof the first intermediate tube31with the screw57b.

The objective lens side tip of the male lead ring55faces in the optical axis direction L1, L2against the smaller diameter step portion of the protruding portion57cof the second intermediate tube57. The eyepiece side tip of the male lead ring55is fitted into the locking projection57dintegrally provided on the outer circumference of the eyepiece side of the second intermediate tube57. Accordingly, the male lead ring55is restricted in movement in the optical axis direction L1, L2by the protruding portion57cand the locking projection57dof the second intermediate tube57.

As described above, the projection54aprojecting in a direction perpendicular to the axis MA is formed on the outer circumference of the female lead ring54. A lead screw55bis formed on the outer circumference of the male lead ring55. The lead screw54bof the female lead ring54is screwed with the lead screw55bof the male lead ring55. The male lead ring55cannot move in the optical axis direction L1, L2, but can rotate inside of the female lead ring54centering on the axis MA. The female lead ring54cannot rotate centering on the axis MA by a locking member (not shown), but can move in the optical axis direction L1, L2by the rotation of the male lead ring55.

A groove52cis formed on each tip of the left and right second focusing rods52. The projection54aof the female lead ring54is fitted into the groove52c. Accordingly, the left and right second focusing rods52are moved in the optical axis direction L1, L2together with the movement of the female lead ring54in the optical axis direction L1, L2. As a result, the left and right first focusing rods51respectively screwed with the left and right second focusing rods52, the left and right connecting pins14respectively connected to the left and right first focusing rods51, and the left and right focusing lens frames13respectively connected to the left and right connecting pins14are moved together with the focusing lenses11,21.

A spur gear56that teeth56aare formed on the outer circumference thereof is provided on the eyepiece side tip of the male lead ring55(seeFIG. 3). The focusing mechanism is composed of the male lead ring55, the female lead ring54, the left and right second focusing rods52, the left and right first focusing rods51, the left and right connecting pins14, and the left and right focusing lens frames13.

In this embodiment, the focusing operation portion composed of the focus knob40and a rotation shaft41is used as a diopter-adjustment-operation-preventing member for preventing an operation of the diopter adjustment wheel53. The focus knob40is disposed on the same axis of the diopter adjustment wheel53. The focus knob40is composed of a base portion40adisposed to the eyepiece side of the male lead ring55, and a cylinder portion40bthat is disposed outside of the diopter adjustment wheel53and extended in the optical axis direction from the outer edge of the base portion40a. The rotation shaft41is rotatably held by the inner circumference of the second intermediate tube57centering on the axis MA, and movable in the optical axis direction L1, L2. The eyepiece side tip of the rotation shaft41integrally fitted to the base portion40aof the focus knob40. Accordingly, the focus knob40is rotatable centering on the axis MA, and movable in the optical axis direction L1, L2. A retaining screw42for preventing the focus knob40from coming out from the second intermediate tube57is screwed to the objective lens side tip of the rotation shaft41.

An internal gear58having teeth58ameshing with the teeth56aof the spur gear56formed on the male lead ring55is formed on a surface that faces the male lead ring55and locates on the base portion40aof the focus knob40(seeFIG. 4). The focus operation portion for transmitting power to the focusing mechanism is composed of the focus knob40, the internal gear58, and the rotation shaft41. The spur gear56can be meshed with the internal gear58, or the meshed state is released by moving the focus knob40along the axis MA. Operation power can be transmitted from the focusing operation portion to the focusing mechanism by meshing the spur gear56with the internal gear58. By releasing the meshed state between the spur gear56and the internal gear58, power transmission from the focusing operation portion to the focusing mechanism is blocked. In this manner, in the present embodiment, a power-transmission-blocking mechanism for releasing the meshing state between the spur gear56and the internal gear58is composed of the rotation shaft41, and the second intermediate tube57, and the power-transmission-blocking mechanism becomes a focus-position-change-preventing member.

A plurality (three in the present embodiment) of concave portions57aextending in the circumferential direction are formed on the inner circumference of the second intermediate tube57with a given space in the axial direction. A groove extending in the circumferential direction is formed on the outer circumference of the rotation shaft41, and an O-ring41ais fitted to the groove. The O-ring41aprotrudes from the outer circumference of the rotation shaft41. The O-ring41acan be put into the concave portion57aby moving the focus knob40along the axis MA, so that the O-ring41ais fitted to the concave portion57a. The O-ring41aand the concave portion57awhere the O-ring41ais fitted compose a click mechanism, and the click mechanism becomes a position-keeping mechanism of the focus knob40. With this click mechanism, the focus knob40can be positioned at three positions in the optical axis direction L1, L2. In the present embodiment, when the O-ring41ais fitted to the concave portion57aformed to the most objective lens side, the spur gear56is meshed with the internal gear58. When the O-ring41ais fitted to the other concave portions57a, in other words, to the one formed to the most eyepiece side or the one formed intermediate position, the meshed state between the spur gear56and the internal gear58is released.

Then, the procedure for adjusting focus of the binoculars is explained. Incidentally, interpupillary adjustment is assumed to be carried out in advance.

At first, in order to adjust diopter difference between the left eye and the right eye of a user, the meshed state between the spur gear56of the male lead ring55and the internal gear58of the focus knob40is released by pulling out the focus knob40to the eyepiece direction (seeFIG. 2). In this state, the O-ring41aof the rotation shaft41is fitted to the concave portion57aformed to the most eyepiece side of the second intermediate tube57. In this instance, since the male lead ring55for moving the left and right focusing lenses11,21together is not connected to the focus knob40, even if the focus knob40is rotated the male lead ring55is not rotated, and the female lead ring54is not moved to the optical axis direction L1, L2, so that the focusing lenses11,21are not moved.

When the meshed state between the spur gear56and the internal gear58is released, the operating knob53bof the diopter adjustment wheel53is not covered by the cylinder portion40bof the focus knob40, and exposed. When the operating knob53bis rotated, the diopter adjustment wheel53is rotated. The rotation of the diopter adjustment wheel53transmitted to the right second focusing rod52through the internal gear53aformed on the inner circumference of the operation portion main body53cand the gear52bformed on the right second focusing rod, so that the right second focusing rod52rotates centering on the focusing axis FA.

The right second focusing rod52is restricted in movement in the optical axis direction L1, L2by engaging with the projection54aof the female lead ring54. The depth of screwing of the right second focusing rod52with respect to the right first focusing rod51varies by the rotation of the right second focusing rod52. In accordance with the depth of screwing, the right first focusing rod51and the right focusing lens frame13are moved in the optical axis direction L1, L2. As a result, the left and right diopter difference of the telescopic optical systems are adjusted corresponding to the left and right diopter difference of the left and right eyes of the user.

After that, the focusing lenses11,21are moved for focusing.

At first, the focus knob40is pushed down to the objective lens side in the optical axis direction from the state shown inFIG. 2, and the spur gear56is meshed with the internal gear58(seeFIG. 1). In this state, the O-ring41aof the rotation shaft41is fitted to the concave portion57aformed to the most objective lens side of the second intermediate tube57. In this instance, the operating knob53bof the diopter adjustment wheel53is covered by the focus knob40. The focus knob40and the male lead ring55are connected through the spur gear56and the internal gear58. Since the operating knob53bis completely covered by the focus knob40, the operating knob53bis not touched by mistake, so that the diopter difference set previously does not change. Accordingly, after adjusting diopter difference, diopter difference can be prevented from being changed.

When the focus knob40is rotated, the male lead ring55is rotated through the internal gear58and the spur gear56, and the female lead ring54is moved in the optical axis direction L1, L2. With the movement of the female lead ring54in the optical axis direction L1, L2, the left and right second focusing rods52, the left and right first focusing rods51, and the left and right focusing lens frames13are moved together in the optical axis direction L1, L2. In this instance, since the right second focusing rod52does not rotate centering on the focusing axis FA, the depth of screwing of the right second focusing rod52with respect to the right first focusing rod51does not change. Accordingly, the relative distance of the right first focusing rod51and the right second focusing rod52in the optical axis direction does not change.

As a result, the focusing lenses11,21are moved together in the optical axis direction L1, L2, so that focusing on an object to be observed is carried out by the left and right telescopic optical systems at the same time. After that, the focus knob40is pulled out to the eyepiece side up to the intermediate position shown inFIG. 5, in other words, up to the position where the O-ring41aof the rotation shaft41is fitted to the concave portion57alocated intermediate position among the three concave portions57aof the second intermediate tube57. When the meshed state between the spur gear56and the internal gear58by pulling out the focus knob40to this position, even if the focus knob40is touched by mistake, focus position does not change. Accordingly, after adjusting focal position the focal position is prevented from being changed.

Even in the state that the focus knob40is pulled up to the intermediate position as shown inFIG. 5, the operating knob53bof the diopter adjustment wheel53is partially covered by the focus knob40, so that the operating knob53bis hardly touched by mistake, and the diopter difference can be prevented from being changed.

According to this embodiment, after adjusting diopter difference, the focus knob40is pushed down, so that the operating knob53bcannot be touched. Accordingly, the diopter difference can be prevented from being changed after adjusting diopter difference. Moreover, after adjusting focus position by pulling out the focus knob40, focus lock state that focus does not change can be created, so that focus position can be prevented from being changed after adjusting focus position. Furthermore, since the click mechanism is adopted for the position-keeping mechanism of the focusing operation portion, the focus knob40can be securely kept at a given position.

In the present embodiment, although the focus knob40is used as the diopter-adjustment-operation-preventing member, the operating knob53bmay be covered by a member (not shown) different from the focus knob40as the diopter-adjustment-operation-preventing member so as not to be touched by mistake.

When the diopter adjusting mechanism has a rotation shaft, it may have a lock mechanism for locking the rotation of the rotation shaft. As the lock mechanism, a holding member for blocking rotation of the rotation shaft may be used.

In the present embodiment, although the focus lock state is created by pulling up the focus knob40, it may be created such that, for example, a lock mechanism (not shown) is provided on the focus knob40, and the focus knob40is fixed to the second intermediate tube57.

Furthermore, in the present invention, focus position can be locked even if the distance to the object to be observed is not near to infinity.

In the present embodiment, although the diopter adjustment mechanism and the focusing mechanism are provided on the bridge portion30, the position where these mechanisms are provided is not limited to the bridge portion30, it may be on the lens barrel10,20or on the periphery thereof.