JP2010243933A - Binocular optical system and binocular - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a binocular optical system whose full length is short in the optical axis direction of an objective lens. <P>SOLUTION: The binocular optical system (100) has a pair of eyepiece optical systems (13), and is mounted to a single objective optical system (11). The binocular optical system (100) includes a reflecting surface (S21) for reflecting a light beam from the objective optical system (11) perpendicularly to the optical axis direction of the objective lens (111), a luminous flux-dividing optical system (S112) for dividing the reflected light on the reflecting surface (S21) in the surface perpendicular to the optical axis direction, a first reflective optical system (100L) that reflects one luminous flux divided by the luminous flux-dividing optical system (S112) on a perpendicular surface a plurality of times and finally guides it to one of the pair of eyepiece optical systems (13), and a second reflective optical system (100R) that reflects the other luminous flux divided by the luminous flux-dividing optical system (S112) on a perpendicular surface a plurality of times and finally guides it to the other of the pair of eyepiece optical systems (13). <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a binocular optical system and binoculars that have a single objective lens and a binocular eyepiece and observe an object to be observed.

  In the finder optical system disclosed in Patent Document 1, an optical image of an object to be observed is condensed by a photographing lens and passes, and then an image that is reflected by a mirror and reversed left and right is formed on a screen. After that, the binocular observation optical system provided above the screen separates the formed image into two overlapping viewing fields at the center of the screen so that it can be seen with the left and right eyes, and is a composite image seen with both eyes. Is formed.

JP-A-7-209699

  However, Patent Document 1 discloses a technique that uses a camera finder as a binocular, but some images of the objective lens appear to overlap. For this reason, the left and right images are not completely seen, and it is not practical as binoculars.

  A binocular optical system having an optical path splitting system has been put into practical use in place of the eyepiece of a telescope, but in order to ensure the optical path length necessary for the image inverting optical system and the binocular optical system, the objective lens back There is a problem that the focus becomes long and becomes large.

  An object of the present invention is to provide a binocular optical system and binoculars having a short overall length in the optical axis direction of an objective lens.

According to the first aspect, the binocular optical system receives a light beam from a single objective optical system and has a pair of eyepiece optical systems. The binocular optical system has two reflecting surfaces for reflecting light rays from the objective optical system in a direction perpendicular to the optical axis direction of the objective lens, and two reflected lights on the reflecting surface in a plane perpendicular to the optical axis direction. And a first reflection that reflects one of the light beams divided by the light beam splitting optical system a plurality of times in a plane perpendicular to the optical axis direction and finally leads to one of the pair of eyepiece optical systems. An optical system, and a second reflective optical system that reflects the other light beam divided by the light beam splitting optical system a plurality of times in a plane perpendicular to the optical axis direction, and finally guides the other light beam to the other of the pair of eyepiece optical systems. Prepare.
According to the configuration of this aspect, the binocular optical system having a short total length in the optical axis direction of the objective lens is obtained by reflecting the light beam a plurality of times in a plane perpendicular to the optical axis direction of the objective lens.

According to the second aspect, the binoculars include a single objective optical system, a reflecting surface that reflects light rays from the objective optical system in a direction perpendicular to the optical axis direction of the objective lens, and reflection on the reflecting surface. A light beam splitting optical system that splits light into two in a plane perpendicular to the optical axis direction, and a first reflection that reflects one light beam split by the light beam splitting optical system a plurality of times in a plane perpendicular to the optical axis direction An optical axis in the optical system, a second reflection optical system that reflects the other light beam divided by the light beam splitting optical system a plurality of times in a plane perpendicular to the optical axis direction, and a last reflection optical system of the first reflection optical system A first eyepiece optical system for observing an image of one light beam reflected in the direction, and a second eyepiece for observing an image of the other light beam reflected in the optical axis direction by the last reflective optical system of the second reflective optical system An optical system.
According to the configuration of this aspect, the first aspect of the binocular optical system includes the single objective optical system of the binocular optical system, the second eyepiece optical system, and the first eyepiece optical system, and has a total length in the optical axis direction of the objective lens. Short binoculars.

  According to the aspect of the present invention, a binocular optical system and binoculars having a short overall length in the optical axis direction of the objective lens can be obtained.

It is a perspective view of the binoculars concerning this embodiment. It is a perspective view of the binocular optical system concerning the 1st example arranged in a body part. It is a top view of the binocular optical system concerning the 1st example seen from the Z-axis direction. It is a perspective view of the binocular optical system which concerns on the 2nd Example arrange | positioned in a body part. It is a top view of the binocular optical system concerning the 2nd example seen from the Z-axis direction. It is a perspective view of the binocular optical system concerning the 3rd example arranged in a body part. It is a top view of the binocular optical system concerning the 3rd example seen from the Z-axis direction. It is a perspective view of the binocular optical system which concerns on the 4th Example arrange | positioned in a body part. It is a top view of the binocular optical system concerning the 4th example seen from the Z-axis direction. It is a top view of the binoculars according to the first to fourth embodiments.

<External configuration of binoculars 10>
FIG. 1 is a perspective view of the binoculars 10 of the present embodiment. The binocular 10 includes an interchangeable lens unit 11 that is an objective optical system, and a binocular adapter including a body unit 12 and a binocular unit 13. Here, the direction of the optical axis LR passing through the center of the interchangeable lens unit 11 is the Z-axis direction, the direction perpendicular to the optical axis LR on the plane where the binocular unit 13 is provided is the X-axis direction, and the Z-axis and X-axis The direction perpendicular to Y is the Y-axis direction. In addition, for the sake of explanation, the coordinate axes shown in the figure indicate the directions of the arrows in the positive direction.

  The interchangeable lens unit 11 is a lens having different specifications according to the purpose of use, such as a zoom lens and a single focus lens. For example, the interchangeable lens unit 11 is equipped with an autofocus (AF) mechanism, a camera shake prevention (Vibration Reduction = VR) mechanism, and the like. The body part 12 is provided with a binocular optical system 100 (see FIG. 2). The body unit 12 is provided with a control unit 14 that performs various controls. In order to observe the binocular unit 13 with both eyes, left and right lens barrels 13L and 13R are formed, and the lens barrels 13L and 13R can be adjusted to the eye width of the observer.

  A mount 15 is further formed on the body 12, and the lens-side mount 15a and the body-side mount 15b are detachable. By making the mount 15 the same as the mount shape of a single-lens reflex camera, an interchangeable lens of a single-lens reflex camera can be used. Further, a contact 16 is formed on each mount portion 15. The contact 16 of the mount unit 15 is electrically connected to the body unit 12 and the interchangeable lens unit 11 for acquiring information of the connected interchangeable lens unit 11, supplying power from the body unit 12, and transmitting arithmetic processing results. Used. For example, the contact 16 of the mount unit 15 transmits to the interchangeable lens unit 11 an optimum autofocus (AF) movement amount calculated by the control unit 14 of the body unit 12 for the interchangeable lens unit 11. The motor in the interchangeable lens unit 11 drives the focus lens with the supplied signal.

  In the binoculars 10, the binocular portion 13 and the body side mount portion 15b are shaped to fit the lens side mount portion 15a of the single-lens reflex camera. For this reason, the observer can attach the interchangeable lens part 11 of various single-lens reflex cameras to the body part 12 according to the objective. Many interchangeable lenses for single-lens reflex cameras have been produced so far, and many types of interchangeable lenses have been produced. For example, there are various types of interchangeable lenses such as a macro interchangeable lens, an interchangeable lens equipped with an anti-shake mechanism, a variable zoom interchangeable lens, or a high magnification interchangeable lens. Therefore, the observer can use the high-performance and high-function interchangeable lens of a single-lens reflex camera with respect to the body portion 12. The observer can change the magnification, the lens diameter, and the like of the interchangeable lens as necessary, and can customize the binoculars 10 that are optimal for the purpose of use. For example, when a macro interchangeable lens is attached to the body portion 12, it can be used as a microscope, and when a zoom interchangeable lens from standard to medium telephoto is used, it becomes a binocular 10 for observing landscapes, etc. Use of a lens makes binoculars suitable for astronomical observation.

<Configuration of the binocular optical system 100>
(First embodiment)
The binocular optical system 100 of the first embodiment will be described with reference to FIGS. FIG. 2 is a perspective view of the binocular optical system 100 of the first embodiment disposed in the body portion 12. FIG. 3 is a plan view of the binocular optical system 100 of the first embodiment viewed from the + Z-axis direction. In FIG. 2, the objective lens 111 in the interchangeable lens unit 11 (see FIG. 1) is also drawn, but is not included in the binocular optical system 100.

  As shown in FIGS. 2 and 3, the binocular optical system 100 of the first embodiment includes a left-eye optical system 100L and a right-eye optical system 100R. The binocular optical system 100 includes one field lens 51, a pair of relay lenses 52 and 53, and a plurality of prisms (21 to 33). The imaging magnification of the relay lens 52 and the imaging magnification of the relay lens 53 are equal. The imaging magnification of the relay lens 52 and the relay lens 53 is preferably about 0.8 to 1.5 times, and particularly preferably about 0.8 to 1.0 times in order to make the binocular optical system 100 compact. Among the plurality of prisms, the reflecting surface S112 has a half prism surface that divides the light beam into halves. All of the reflection surfaces S111 and reflection surfaces S113 to S127 other than the reflection surface S112 are total reflection surfaces that totally reflect the light flux. In the following embodiment, an example using a plurality of prisms is shown. However, a part or all of the prisms may be replaced with a plate-like mirror, or may be divided, combined or combined.

  The objective lens 111, the right-angle prism 21, the field lens 51, and the right-angle prism 22 are optical members shared by the left-eye optical system 100L and the right-eye optical system 100R. Light entering from the object to be observed IM through the objective lens 111 is bent in the −Y-axis direction by the reflecting surface S111 of the right-angle prism 21 and is firstly transmitted through the field lens 51 disposed below the right-angle prism 21. An image IM1 is formed. The field lens 51 may be forward or backward as long as it is in the vicinity of the primary image IM1. Thereafter, the light beam that forms the primary image IM1 is divided into a reflected light beam and a transmitted light beam at the reflecting surface S112 where the right-angle prism 22 and the right-angle prism 28 are joined. The divided light beams are respectively distributed to the left-eye optical system 100L and the right-eye optical system 100R.

Hereinafter, the left-eye optical system 100L and the right-eye optical system 100R will be described in detail.
First, the left-eye optical system 100L will be described. The light beam reflected in the −X-axis direction by the reflection surface S112 of the right-angle prism 22 is bent in the −Y-axis direction by the reflection surface S113 of the right-angle prism 23 and has two reflection surfaces provided therebelow. Is incident on. The light beam incident on the right-angle prism 24 is reflected in the −X axis direction by the reflecting surface S114, then reflected by the reflecting surface S115, and exits in the + Y axis direction. Thereafter, the light beam directed toward the + Y-axis direction passes through the relay lens 52 disposed above the right-angle prism 24 and enters the right-angle prism 25 having the same shape as the right-angle prism 24. The light beam incident on the right-angle prism 25 is reflected by the reflecting surface S116 in the + X-axis direction, and then reflected by the reflecting surface S117 and exits in the -Y-axis direction. The light beam emitted from the right-angle prism 25 is directed in the + Z-axis direction by the reflecting surface S118 of the right-angle prism 26 provided thereunder, and is incident on the parallel plane prism 27 disposed in the lens barrel 13L (see FIG. 1). . From the reflecting surface S111 of the right-angle prism 21 to the reflecting surface S118 of the right-angle prism 26, the light beam is reflected eight times.

  The light beam incident on the parallel plane prism 27 is sequentially reflected by the reflecting surfaces S119 and S120 and enters the left eyepiece 131L. In front of the left eyepiece 131L, the left eye image IM-L of the object IM is formed as an erect image. Here, the parallel plane prism 27 and the left eyepiece 131L are arranged in the lens barrel 13L shown in FIG.

  Next, the right-eye optical system 100R will be described. The light beam transmitted through the reflecting surface S112, which is a joint surface between the right-angle prism 22 and the right-angle prism 28, enters the right-angle prism 28 and is reflected in the + X-axis direction by the reflection surface S121. The light beam reflected by the reflecting surface S121 of the right-angle prism 28 enters a parallel plane prism 29 provided for adjusting the length of the optical path in the glass material, and is reflected by the reflecting surface S122 of the right-angle prism 30 adjacent thereto. And injected in the + Y-axis direction. The light beam emitted from the right-angle prism 30 passes through the relay lens 53 having the same focal length as the relay lens 52 and enters the right-angle prism 31 having the same shape as the right-angle prism 25. In the right-angle prism 31, the light beam is reflected by the reflecting surface S123 in the −X axis direction and reflected by the reflecting surface S124 in the −Y axis direction. The light beam directed in the −Y-axis direction is emitted toward the + Z-axis direction at the reflecting surface S125 of the right-angle prism 32 disposed below the right-angle prism 31. Thereafter, the light beam enters a parallel plane prism 33 arranged in the lens barrel 13R (see FIG. 1). From the reflection surface S111 of the right-angle prism 21 to the reflection surface S125 of the right-angle prism 32, the light beam is reflected six times.

  The light beam incident on the parallel plane prism 33 is sequentially reflected by the reflecting surfaces S126 and S127 and enters the right eyepiece 131R. The right eye image IM-R of the object IM is formed as an erect image before the right eyepiece 131R. Here, the parallel plane prism 33 and the right eyepiece 131R are arranged in the lens barrel 13R shown in FIG. The focal length of the left eyepiece 131L and the right eyepiece 131R is about 8 mm to 15 mm.

  As shown in FIG. 3, the binocular optical system 100 of the first embodiment is substantially symmetric with respect to the Y axis that passes through the center of the field lens 51. If the height of the right-angle prism is H and the minimum distance between the optical members separated in the Y-axis direction is ΔH, the height of the binocular optical system 100 of the first embodiment is about 4H + 2ΔH. is there. In addition, the width from the Y axis that passes through the center of the field lens 51 to both ends is D1.

  In the binocular optical system 100 of the first embodiment, the right-angle prisms 25 and 31, the right-angle prisms 26 and 32, the relay lenses 52 and 53, the reflection surface S115 of the right-angle prism 24, and the reflection surface S122 of the right-angle prism 30. Is symmetric with respect to the Y axis that passes through the center of the field lens 51 in the XY plane. For this reason, the length of the optical path from the field lens 51 to the relay lens 52 of the left-eye optical system 100L and the length of the optical path in the glass material from the field lens 51 to the relay lens 53 of the right-eye optical system 100R are equal to each other. The lengths of the optical path from the relay lens 52 of the left-eye optical system 100L to the left-eye image IM-L and the length of the optical path from the relay lens 53 of the right-eye optical system 100R to the right-eye image IM-R are also equal to each other. Therefore, the observer can feel the brightness and magnification of the left-eye optical system 100L and the right-eye optical system 100R as well.

  In the binocular optical system 100 of the first embodiment, most of the optical members are arranged compactly on the XY plane, so that not only the thickness is reduced in the Z-axis direction but also the area on the XY plane is larger. Can be smaller.

(Second embodiment)
The binocular optical system 100 according to the second embodiment will be described with reference to FIGS. FIG. 4 is a perspective view of the binocular optical system 100 of the second embodiment arranged in the body portion 12. FIG. 5 is a plan view of the binocular optical system 100 of the second embodiment viewed from the + Z-axis direction. The same components as those described in the first embodiment will be described with the same reference numerals. In FIG. 4, the objective lens 111 is also drawn, but is not included in the binocular optical system 100.

  As shown in FIGS. 4 and 5, in the second embodiment, the objective lens 111, the right-angle prism 21, the field lens 51 and the right-angle prism 22 are optical members shared by the left-eye optical system 100L and the right-eye optical system 100R. It is. Further, since the optical path before reaching the right-angle prism 22 is the same as that in the first embodiment, description thereof is omitted.

Hereinafter, the left-eye optical system 100L and the right-eye optical system 100R from the right-angle prism 22 will be described in detail.
First, in the left-eye optical system 100L, the light beam reflected in the −X-axis direction by the reflecting surface S212 of the right-angle prism 22 enters the parallel plane prism 34 provided for adjusting the length of the optical path in the glass material. The light beam transmitted through the parallel plane prism 34 is reflected by the reflecting surface S213 of the right-angle prism 35, travels in the -Y-axis direction, is reflected by the reflecting surface S214 in the X-axis direction, and is disposed in the + X-axis direction of the right-angle prism 35. 36 is incident. The light beam incident on the right-angle prism 36 is bent in the + Y-axis direction by the reflection surface S215 and is transmitted through the parallel plane prism 34 again. Thereafter, the light beam enters a right-angle prism 25 provided above the parallel plane prism 34. The light beam incident on the right-angle prism 25 is reflected by the reflecting surface S216 in the −X axis direction, reflected by the reflecting surface S217, and emitted in the −Y axis direction. The light beam emitted from the right-angle prism 25 is directed in the + Z-axis direction by the reflection surface S218 of the right-angle prism 26 provided therebelow, and is incident on the parallel plane prism 27 disposed in the lens barrel 13L (see FIG. 1). . From the reflection surface S211 of the right-angle prism 21 to the reflection surface S218 of the right-angle prism 26, the light beam is reflected eight times.

  The light beam incident on the parallel plane prism 27 is sequentially reflected by the reflecting surfaces S219 and S220 to form an erect left eye image IM-L and is incident on the left eyepiece 131L.

  Next, the right-eye optical system 100R will be described. The light beam transmitted through the reflecting surface S212, which is a joint surface between the right-angle prism 22 and the right-angle prism 28, enters the right-angle prism 28, and is reflected in the + X-axis direction by the reflection surface S221. The light beam reflected by the reflecting surface S221 of the right-angle prism 28 enters a parallel plane prism 29 provided to adjust the length of the optical path in the glass material. The light beam incident on the parallel plane prism 29 is reflected by the reflecting surface S222 of the right-angle prism 30 adjacent to the parallel plane prism 29 and is emitted in the + Y-axis direction. The light beam emitted from the right-angle prism 30 enters the parallel plane prism 37, is sequentially reflected by the reflection surfaces S223 and S224, and is emitted in the + Y-axis direction. Then, the light beam passes through the relay lens 53 having the same focal length as that of the relay lens 52 and enters the right-angle prism 31. The light beam is sequentially reflected by the reflecting surfaces S225 and S226 of the right-angle prism 31, and is directed in the -Y-axis direction. Further, the light beam is reflected by the reflecting surface S227 of the right-angle prism 32 and is emitted toward the + Z-axis direction. Thereafter, the light beam is incident on a parallel plane prism 33 disposed in the lens barrel 13R (see FIG. 1). From the reflection surface S211 of the right-angle prism 21 to the reflection surface S227 of the right-angle prism 32, the light beam is reflected eight times.

  The light beam incident on the parallel plane prism 33 is sequentially reflected by the reflecting surfaces S228 and S229 to form an erect right eye image IM-R, and enters the right eyepiece 131R.

  As shown in FIG. 5, the binocular optical system 100 of the second example is symmetric with respect to the Y axis that passes through the center of the field lens 51. If the height of the right-angle prism is H and the minimum distance between optical members separated in the Y-axis direction is ΔH, the height of the binocular optical system 100 of the second embodiment is about 4H + 2ΔH. is there. The width from the center of the field lens 51 to both ends is D1.

  Further, in the binocular optical system 100 of the second embodiment, the right-angle prisms 25 and 31, the right-angle prisms 26 and 32, the relay lenses 52 and 53, the reflection surface S213 of the right-angle prism 35, and the reflection surface S223 of the right-angle prism 37. The reflecting surface S214 of the right-angle prism 35 and the reflecting surface S222 of the right-angle prism 30 are symmetrical with respect to the Y axis that passes through the center of the field lens 51 on the XY plane. For this reason, the length of the optical path from the field lens 51 to the relay lens 52 of the left-eye optical system 100L and the length of the optical path in the glass material from the field lens 51 to the relay lens 53 of the right-eye optical system 100R are equal to each other. The lengths of the optical path from the relay lens 52 of the left-eye optical system 100L to the left-eye image IM-L and the length of the optical path from the relay lens 53 of the right-eye optical system 100R to the right-eye image IM-R are also equal to each other. Therefore, the observer can feel the brightness and magnification of the left-eye optical system 100L and the right-eye optical system 100R as well.

  In the binocular optical system 100 of the second embodiment, most of the optical members are arranged compactly on the XY plane, so that not only the thickness in the Z-axis direction becomes thinner, but also the area on the XY plane increases. Can be smaller.

(Third embodiment)
A binocular optical system 100 according to a third embodiment will be described with reference to FIGS. FIG. 6 is a perspective view of the binocular optical system 100 of the third embodiment disposed in the body portion 12. FIG. 7 is a plan view of the binocular optical system 100 of the third embodiment viewed from the + Z-axis direction. The same components as those described in the first and second embodiments will be described with the same reference numerals. Further, although the objective lens 111 is also illustrated in FIG. 6, it is not included in the binocular optical system 100.

  As shown in FIGS. 6 and 7, in the third embodiment, the objective lens 111, the right-angle prism 21, the field lens 51 and the right-angle prism 22 are optical members shared by the left-eye optical system 100L and the right-eye optical system 100R. It is. Further, since the optical path before reaching the right-angle prism 22 is the same as that in the first and second embodiments, the description thereof is omitted. Hereinafter, the other left-eye optical system 100L and the right-eye optical system 100R will be described in detail.

  First, the left-eye optical system 100L will be described. The light beam reflected in the −X-axis direction by the reflecting surface S312 of the right-angle prism 22 is incident on a parallel plane prism 38 provided for adjusting the length of the optical path in the glass material. The light beam that has passed through the parallel plane prism 38 is reflected in the + Y-axis direction by the reflecting surface S313 of the right-angle prism 39, and is incident on the right-angle prism 40 provided thereabove. The light beam incident on the right-angle prism 40 is reflected by the reflecting surface S314 and exits in the + X-axis direction. The light beam emitted from the right-angle prism 40 is bent in the −Y-axis direction by the reflection surface S315 of the right-angle prism 41 and enters the right-angle prism 26 provided below the right-angle prism 41. The light beam incident on the right-angle prism 26 is directed in the + Z-axis direction by the reflecting surface S316 and is incident on the parallel plane prism 27 disposed in the lens barrel 13L (see FIG. 1). From the reflecting surface S311 of the right-angle prism 21 to the reflecting surface S316 of the right-angle prism 26, the light beam is reflected six times.

  The light beam incident on the parallel plane prism 27 is sequentially reflected by the reflecting surfaces S317 and S318, forms an erect left eye image IM-L, and enters the left eyepiece 131L.

  Next, the right-eye optical system 100R will be described. The light beam that has passed through the reflecting surface S312 that is a joint surface between the right-angle prism 22 and the right-angle prism 28 enters the right-angle prism 28 and is reflected in the + X-axis direction by the reflection surface S319. The light beam emitted from the right-angle prism 28 enters the right-angle prism 42, is reflected by the reflection surface S320, and is emitted in the + Y-axis direction. The light beam emitted from the right-angle prism 42 passes through the relay lens 53 having the same focal length as that of the relay lens 52 and enters the right-angle prism 43. The light beam incident on the right-angle prism 43 is reflected in the −X-axis direction by the reflection surface S321, and is reflected again in the −Y-axis direction by the reflection surface S322 of the right-angle prism 44. Then, the light beam emitted from the right-angle prism 44 is emitted toward the + Z-axis direction via the reflection surface S323 of the right-angle prism 32 disposed below the right-angle prism 44. Thereafter, the light beam enters a parallel plane prism 33 arranged in the lens barrel 13R (see FIG. 1). From the reflection surface S311 of the right-angle prism 21 to the reflection surface S323 of the right-angle prism 32, the light beam is reflected six times.

  The light beam incident on the parallel plane prism 33 is sequentially reflected by the reflecting surfaces S324 and S325, forms an erect right eye image IM-R, and enters the right eyepiece 131R.

  As shown in FIG. 7, the binocular optical system 100 of the third example is not symmetric with respect to the Y axis that passes through the center of the field lens 51. If the height of the right-angle prism is H and the minimum distance between the optical members separated in the Y-axis direction is ΔH, the height of the left-eye optical system 100L of the binocular optical system 100 of the third embodiment is The height of the right-eye optical system 100R is about 4H + 2ΔH at about 3H + 2ΔH. Further, a width D2 from the Y axis that passes through the center of the field lens 51 to the left end is larger than a width D1 to the right end.

  However, also in the binocular optical system 100 of the third embodiment, the optical path from the field lens 51 to the relay lens 52 of the left-eye optical system 100L, and from the field lens 51 to the relay lens 53 of the right-eye optical system 100R and in the glass material The lengths of the optical paths are equal to each other. The lengths of the optical path from the relay lens 52 of the left-eye optical system 100L to the left-eye image IM-L and the length of the optical path from the relay lens 53 of the right-eye optical system 100R to the right-eye image IM-R are also equal to each other.

  In the binocular optical system 100 of the third embodiment, most of the optical members are arranged compactly on the XY plane, so that not only the thickness is reduced in the Z-axis direction but also the area on the XY plane is larger. Can be smaller.

(Fourth embodiment)
A binocular optical system 100 according to a fourth embodiment will be described with reference to FIGS. FIG. 8 is a perspective view of the binocular optical system 100 of the fourth embodiment disposed in the body portion 12. FIG. 9 is a plan view of the binocular optical system 100 of the fourth embodiment viewed from the + Z-axis direction. The same components as those described in the first to third embodiments will be described with the same reference numerals. Further, although the objective lens 111 is also illustrated in FIG. 8, it is not included in the binocular optical system 100.

  As shown in FIGS. 8 and 9, the binocular optical system 100 of the fourth embodiment includes a left-eye optical system 100L and a right-eye optical system 100R. Light entering from the object to be observed IM through the objective lens 111 is bent in the −Y-axis direction by the reflecting surface S411 of the right-angle prism 21, and is firstly transmitted through the field lens 51 disposed below the right-angle prism 21. An image IM1 is formed. The objective lens 111, the right-angle prism 21, and the field lens 51 so far are optical members shared by the left-eye optical system 100L and the right-eye optical system 100R. Hereinafter, the other left-eye optical system 100L and the right-eye optical system 100R will be described in detail.

  In the left-eye optical system 100L, the light beam that has passed through the field lens 51 is incident on a right-angle prism 45 having two reflecting surfaces provided therebelow. The light beam incident on the right-angle prism 45 is sequentially reflected by the reflecting surfaces S412 and S413, and is emitted toward the + Y-axis direction, which is the opposite direction to the incident light. Thereafter, the light beam directed in the + Y-axis direction is transmitted through a parallel plane prism 46 provided for adjusting the length of the optical path in the glass material. The light beam emitted from the parallel plane prism 46 passes through the relay lens 52 disposed above the parallel plane prism 46 and enters the right-angle prism 25. The light beam incident on the right-angle prism 25 is sequentially reflected by the reflection surfaces S414 and S415 and is emitted again in the −Y-axis direction. The light beam emitted from the right-angle prism 25 is directed in the + Z-axis direction by the reflecting surface S416 of the right-angle prism 26 provided below the right-angle prism 25, and is a parallel plane prism 27 disposed in the lens barrel 13L (see FIG. 1). Is incident on. From the reflecting surface S411 of the right-angle prism 21 to the reflecting surface S416 of the right-angle prism 26, the light beam is reflected six times.

  The light beam incident on the parallel plane prism 27 is sequentially reflected by the reflection surfaces S417 and S418 to form an erect left eye image IM-L and is incident on the left eyepiece 131L.

  Next, the right-eye optical system 100R will be described. The light beam that has passed through the field lens 51 sequentially passes through the right-angle prisms 45 and 47. The light beam transmitted through the right-angle prism 47 is incident on a right-angle prism 48 having two reflecting surfaces. The light beam incident on the right-angle prism 48 is sequentially reflected by the reflecting surfaces S419 and S420, and is emitted toward the + Y-axis direction, which is the opposite direction to the incident light. The light beam emitted from the right-angle prism 48 passes through the relay lens 53 having the same focal length as the relay lens 52 and enters the right-angle prism 31 having the same shape as the right-angle prism 25. The light beam in the + Y-axis direction is changed to the −Y-axis direction by sequentially reflecting on the reflecting surfaces S421 and S422 of the right-angle prism 31, and the + Z-axis is obtained via the reflection surface S423 of the right-angle prism 32 disposed below the right-angle prism 31. Ejected in the direction. Thereafter, the light beam enters the plane parallel prism 33. From the reflecting surface S411 of the right-angle prism 21 to the reflecting surface S423 of the right-angle prism 32, the light beam is reflected six times.

  The light beam incident on the parallel plane prism 33 is sequentially reflected by the reflecting surfaces S424 and S425, forms an erect right eye image IM-R, and enters the right eyepiece lens 131R.

  As shown in FIG. 9, if the height of the right-angle prism is H and the minimum distance between the optical members separated in the Y-axis direction is ΔH, the left eye of the binocular optical system 100 of the fourth embodiment is used. The height of the optical system 100L and the right-eye optical system 100R is about 4H + ΔH, but there is a step of height H. Further, in the binocular optical system 100 of the fourth embodiment, the width from the Y axis passing through the center of the field lens 51 to both ends is D1.

  In the binocular optical system 100 of the fourth embodiment, the optical path from the field lens 51 to the relay lens 52 of the left-eye optical system 100L, and the optical path from the field lens 51 to the relay lens 53 of the right-eye optical system 100R and the optical path in the glass material. Are equal to each other. Further, the lengths of the optical path from the relay lens 52 of the left-eye optical system 100L to the left-eye image IM-L, the optical path from the relay lens 53 of the right-eye optical system 100R to the right-eye image IM-R, and the optical path in the glass material are also equal.

  In the binocular optical system 100 of the fourth embodiment, most of the optical members are arranged compactly on the XY plane, so that not only the thickness is reduced in the Z-axis direction but also the area on the XY plane is larger. Can be smaller.

<Comparison of the first to fourth embodiments>
FIG. 10 is a top view of the binoculars 10 according to the first to fourth embodiments. A portion surrounded by a broken line shown in FIG. 10 is the binocular optical system 100. Here, in the XZ plane, the lens barrel 13L can be rotated around the respective incident optical axes as indicated by the arrow AR-L, and the lens barrel 13R can be rotated as indicated by the arrow AR-R. . Thereby, the distance between the two lens barrels 13L and 13R can be adjusted, and the distance may be changed by an observer.

  In addition, since most of the optical members of the binocular optical system 100 are compact in the body portion 12, the length of the binoculars 10 in the Z-axis direction becomes shorter. At this time, if the length of the interchangeable lens portion 11 is L1, the thickness of the body portion 12 is L2, and the length of the binocular portion 13 is L3, the overall length L of the binoculars 10 is L1 + L2 + L3, and the observer The total length L can be handled sufficiently.

In the first to fourth embodiments described above, the length and height of the binocular optical system on the XY plane are as shown in Table 1.

  In all the embodiments, the overall optical path of the left-eye optical system 100L and the right-eye optical system 100R of the binocular optical system 100 and the length of the optical path in the glass material are equal to each other, and the lengths in the Z-axis direction are also equal to each other. Here, the length D2 is larger than D1, and the height H of the prism is larger than the minimum distance ΔH. Therefore, as shown in Table 1, it is clear that the area (2D1) × (4H + 2ΔH) of the binocular optical system 100 according to the first and second examples is the smallest. Compared to the first and second embodiments, the third embodiment is wider and the fourth embodiment is higher.

  In order for the right-eye image IM-R and the left-eye image IM-L to be erect images with no inclination with respect to the object IM, the light is finally reflected after being first reflected on the reflecting surface of the right-angle prism 21. The number of reflections from the plane perpendicular to the axial direction to the time before reflection in the + Z direction needs to be an even number. In addition, the direction and direction of the optical axis of the incident light beam immediately before the last reflection in the + Z direction needs to coincide with the direction and direction of the optical axis of the light beam reflected on the reflecting surface of the right-angle prism 21 first. It is. That is, since all the examples of this embodiment satisfy these two conditions, an erect image having no inclination can be obtained.

  The optimum embodiment of the present invention has been described in detail above. However, as will be apparent to those skilled in the art, the present invention can be implemented with various modifications and variations within the technical scope thereof.

10 ... Binoculars 11 ... Interchangeable lens
DESCRIPTION OF SYMBOLS 12 ... Body part 13 ... Binocular part, 13L, 13R ... Lens barrel 14 ... Control part 15a ... Interchangeable lens side mount part, 15b ... Body side mount part 16 ... Contact 21-26, 28, 30-32, 35, 36, 39-45, 47, 48 ... right angle prism 27, 29, 33, 34, 37, 38, 46 ... parallel plane prism 51 ... field lens 52, 53 ... relay lens 100 ... binocular optical system 100L ... left eye optical system, 100R ... Right-eye optical system 111 ... Objective lens 131L ... Left eyepiece lens, 131R ... Right eyepiece lens AR-L, AR-R ... Arrows indicating movement of the lens barrel D1, D2 ... From the Y axis passing through the field lens of the optical system to both ends △ H… Minimum prism spacing H… Right angle prism height IM… Observation object IM1… Primary image M-L ... left image, IM-R ... right image L ... binoculars length L1 ... interchangeable lens unit of length, L2 ... body portion of the length, L3 ... binocular unit length of,
LR ... Optical axis S111 to S127 ... Reflecting surface of the first embodiment S211 to S229 ... Reflecting surface of the second embodiment S311 to S325 ... Reflecting surface of the third embodiment S411 to S425 ... of the fourth embodiment Reflective surface

Claims (7)

In a binocular optical system having a pair of eyepiece optical systems and receiving light from a single objective optical system,
A reflecting surface for reflecting light rays from the objective optical system in a direction perpendicular to the optical axis direction of the objective lens;
A beam splitting optical system that splits the reflected light from the reflecting surface into two in a plane perpendicular to the optical axis direction;
A first reflection optical system that reflects one light beam divided by the light beam splitting optical system a plurality of times in a plane perpendicular to the optical axis direction, and finally guides it to one of the pair of eyepiece optical systems;
A second reflection optical system that reflects the other light beam divided by the light beam splitting optical system a plurality of times in a plane perpendicular to the optical axis direction, and finally guides the other light beam to the other of the pair of eyepiece optical systems;
Binocular optical system.   The first reflection optical system and the second reflection optical system are configured by prisms, and the distance that the one light beam passes through the prism of the first reflection optical system and the other light beam is the second reflection optical system. The binocular optical system according to claim 1, wherein a distance passing through the prism of the system is the same. A relay lens is provided in each of the first reflective optical system and the second reflective optical system,
The binocular optical system according to claim 1, wherein an imaging magnification of the relay lens of the first reflective optical system is equal to an imaging magnification of the relay lens of the second reflective optical system.   The binocular optical system according to any one of claims 1 to 3, wherein the number of reflections is an even number of times for the two light beams in the vertical plane. A single objective optical system;
A reflecting surface for reflecting light rays from the objective optical system in a direction perpendicular to the optical axis direction of the objective lens;
A beam splitting optical system that splits the reflected light from the reflecting surface into two in a plane perpendicular to the optical axis direction;
A first reflection optical system that reflects one light beam divided by the light beam splitting optical system a plurality of times in a plane perpendicular to the optical axis direction;
A second reflecting optical system that reflects the other light beam split by the light beam splitting optical system a plurality of times in a plane perpendicular to the optical axis direction;
A first eyepiece optical system for observing an image of one light beam reflected in the optical axis direction by the last reflective optical system of the first reflective optical system;
A second eyepiece optical system for observing an image of the other light beam reflected in the optical axis direction by the last reflective optical system of the second reflective optical system;
Binoculars equipped with.   The binoculars according to claim 5, wherein the objective optical system is an interchangeable lens that can be attached to and detached from a body of the binoculars.   The binoculars according to claim 5 or 6, wherein the first eyepiece optical system and the second eyepiece optical system are rotatable around an optical axis reflected at the end of each reflection optical system.