JPH10115787A - Plural-field optical device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To shield needless light made incident from the aperture of a sub mirror in narrow field by covering the aperture in the case of forming the image of the narrow field. SOLUTION: In the case of the narrow field, narrow field luminous flux 9 is condensed once at an intermediate image-formation point 11 by a narrow field reflection objective optical system 3 constituted of a main mirror 1 and the sub mirror 2, passes through a relay optical system 5 and is formed into an image on an image pickup element 12. At such a time, a shutter 15 is kept in a closed state by a shutter opening/closing mechanism 16 and the aperture of the sub mirror 2 is covered to prevent the needless light from being made incident through a wide field optical system 4. Meanwhile, in the case of wide field, wide field luminous flux 10 passes through the wide field reflection objective optical system 4 and is condensed once at the point 11, passes through the optical system 5 and is formed into the image the element 12. At such a time, the shutter 15 is kept in an opened state by the mechanism 16 and the aperture of the sub mirror 21 is uncovered, so that the luminous flux 10 passes through the aperture and is condensed at the point 11.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a multi-field optical device having two or more different visual fields, and forming an image of any one of the visual fields on an image plane selectively defined.

[0002]

2. Description of the Related Art First, a conventional multi-field optical technique will be described. FIG. 7 and FIG.
FIG. 1 is a configuration diagram showing a conventional multi-field optical device which is No. 74025. In the figure, 1 is a primary mirror, 2 is a secondary mirror, 3 is a narrow-field reflection objective optical system, 4 is a wide-field objective optical system, 5 is a relay optical system, 6 is a sub-mirror support member, and 7 is a wide-field objective optical system. A driving device, 8 is a visual field selecting device, 9 is a narrow visual field light beam, 10 is a wide visual field light beam, 11 is an intermediate image forming point, and 12 is an image sensor.

The conventional multi-field optical device shown in FIG. 7 is configured as described above, and operates as follows. When a signal indicating a narrow visual field is output from the visual field selecting device 8, the wide visual field objective optical system driving device 7 moves the wide visual field objective optical system 4 to a position where the narrow visual field light flux 9 is not blocked. In this case, a narrow-field reflecting objective optical system 3 is constituted by the main mirror 1 and the sub-mirror 2, and the narrow-field light beam 9 is reflected by the main mirror 1 and the sub-mirror 2 and becomes 1 at the intermediate image point 11.
Collect light twice. The condensed light passes through the relay optical system 5 and is condensed on the image sensor 12, so that a narrow-field image is obtained on the image sensor 12. Next, when a signal indicating a wide field of view is output from the field of view selecting device 8, the wide field objective optical system driving device 7
Moves the wide-field objective optical system 4 to a position between the primary mirror 1 and the secondary mirror 2 on the optical axis. Since the secondary mirror 2 is provided with an opening, the wide-field light beam 10 passes through the opening, passes through the wide-field objective optical system 4, and condenses on the intermediate imaging point 11. The condensed light passes through the relay optical system 5 and is condensed on the image pickup device 12 to obtain a wide-field image. The secondary mirror 2 has a wide-field light beam 10
Therefore, there is no need to move the secondary mirror 2. However, in the case of this configuration, the aperture of the sub-mirror 2 necessary for not blocking the wide-field light beam 10 becomes large, which is larger than the original shielding of the narrow-field light beam 9 by the sub-mirror 2 itself, and the brightness as an optical device The size is dark for its size.

The conventional multi-field optical device shown in FIG. 8 configured to improve this point operates as follows. When a signal indicating a narrow visual field is issued from the visual field selecting device 8, the visual field switching unit moving device 14 moves the visual field switching unit 13 in the optical axis direction, and moves to a position where the sub mirror 2 faces the primary mirror 1, Stop. At this time, the narrow-field luminous flux 9 is condensed at the intermediate image point 11 to form the narrow-field reflection objective optical system 3 by the primary mirror 1 and the sub-mirror 2, passes through the relay optical system 5, and narrows to the image pickup device 12. Obtain an image of the field of view. Next, when a signal for instructing a wide field of view is output from the field of view selecting device 8, the field switching unit moving device 14 moves the field switching unit 13 in the opposite direction of the optical axis, and the wide field light beam 10 is changed to the wide field objective optical system 4. Stops at the position where light is condensed on the intermediate imaging point 11. The light beam condensed at the intermediate image point 11 passes through the relay optical system 5 and forms an image on the image pickup device 12 to obtain a wide-field image. At this time, the wide-field light beam 10 passes through the aperture provided in the sub-mirror 2, but the sub-mirror 2 can be positioned near the intermediate imaging point 11 in the wide-field state. It is squeezed at the position of the secondary mirror, and the diameter of the opening of the secondary mirror 2 can be reduced. Since the reflection type optical system as shown in FIGS. 7 and 8 is originally shielded by the secondary mirror, the central portion of the secondary mirror is not used originally. Therefore, if the aperture of the sub-mirror can be made smaller than the size of the part not used originally, the original brightness of this type of optical device can be obtained. As described above, the visual field switching can be realized only by relatively simple position control of the visual field switching unit 13 in the optical axis direction, and a space for storing the sub-mirror 2 and the wide visual field objective optical system 4 in a place where the light flux is not blocked is required. Therefore, it is relatively small as a device.

[0005]

However, the above-mentioned conventional multi-field optical device can be greatly improved in design flexibility by making improvements in the following points. That is, as shown in FIG. 7, when located in the position of the narrow field of view, since there is an opening at the center of the sub-mirror, light irrelevant to the image to be obtained through the opening enters from the outside. As a result, unnecessary light spreads over the entire image pickup element serving as an image plane, so that a so-called fog state occurs, and the contrast of the obtained image is reduced. Further, in the configuration shown in FIG. 8, since the wide-field objective optical system 4 is provided in front of the opening of the sub mirror 2 even in a narrow field of view, this lens has an image forming function, and an unnecessary image is formed on the image sensor. May be. That is, the focal length of the wide-field objective optical system is approximately equal to the distance from the wide-field objective optical system to the sub-mirror 2, but in a narrow field of view, the intermediate imaging point 11 is located further away from the wide-field optical system 4. Therefore, the intermediate imaging point 11 has its conjugate point at a finite position in the object space by the wide-field optical system, and an object near the conjugate point forms an image on the image sensor surface, and A ghost appears where an unnecessary image does not overlap the desired image.

The present invention has been made to improve such a point, and provides a means for shielding unnecessary light entering from the aperture of the secondary mirror in a narrow field of view.

[0007]

According to a first aspect of the present invention, there is provided a multi-field optical apparatus having a shielding means for shielding the aperture when forming a narrow-field image.

A multi-field optical device according to a second aspect of the present invention is a device for integrating a sub-mirror provided with an aperture and a wide-field objective optical system into a field switching unit, and moving the field switching unit in the optical axis direction. A shutter that blocks the opening when forming an image in a narrow field of view, a plate member that pulls the shutter in a narrow field of view and blocks the opening,
It has a spring member that pulls the shutter in the opposite direction in a wide field of view and returns it to its original position.

A multi-field optical device according to a third aspect of the present invention is a device for integrating a sub-mirror provided with an aperture and a wide-field objective optical system into a field switching unit, and moving the field switching unit in the optical axis direction. A shutter that blocks the opening when forming an image in a narrow field of view, a wire that pulls the shutter in a narrow field of view and blocks the opening,
It has a spring member that pulls the shutter in the opposite direction in a wide field of view and returns it to its original position.

A multi-field optical device according to a fourth aspect of the present invention is a device for switching a visual field switching unit in an optical axis direction by integrating a secondary mirror provided with an aperture and a wide-field objective optical system into a visual field switching unit. An optical plate having a shielding portion for shielding the aperture when forming a narrow-field image near an image formed by the relay optical system of the aperture stop, an optical plate having no shielding portion, A switching mechanism is provided for switching between an optical plate with a shield and an optical plate without a shield in accordance with an instruction.

A multi-field optical apparatus according to a fifth aspect of the present invention integrates a sub-mirror provided with an aperture with a wide-field objective optical system to form a field switching unit, and moves the field switching unit in the optical axis direction. An optical plate having a shielding portion for shielding the opening, an optical plate having no shielding portion, an optical filter having a shielding portion, an optical filter having no shielding portion,
And a switching means for switching these optical plates and optical filters in accordance with an instruction from a visual field selection and filter selection device.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION

First Embodiment Hereinafter, a first embodiment of a multi-field optical device according to the present invention will be described.
Will be described with reference to FIG. In the figure, 1 is a primary mirror, 2 is a secondary mirror,
3 is a narrow-field reflective objective optical system, 4 is a wide-field objective optical system, 5
Is a relay optical system, 8 is a visual field selecting device, 9 is a narrow visual field light beam,
Reference numeral 10 denotes a wide-field luminous flux, 11 denotes an intermediate image point, 12 denotes an image pickup device, 12 denotes a field switching unit, and the sub-mirror 2 and the wide-field objective optical system 4 are housed and integrated in the same lens barrel. It is driven by the view switching unit moving device. Reference numeral 15 denotes a shutter, and 16 denotes a shutter opening / closing mechanism that opens and closes the shutter 15.

The multi-field optical device according to the present invention is configured as described above, and operates as follows. At the time of the narrow visual field, the narrow-field light beam 9 is once condensed at the intermediate image point 11 by the narrow-field reflective objective optical system 3 composed of the primary mirror 1 and the sub-mirror 2, passes through the relay optical system 5 and is on the image sensor 12. Image. At this time, the shutter 15 is kept closed by the shutter opening / closing mechanism 16, and the opening of the secondary mirror 2 is closed to
Unnecessary light is prevented from entering through.

On the other hand, at the time of a wide field of view, the wide field light beam 10 passes through the wide field objective optical system 4 and is once condensed at the intermediate image forming point 11.
The light passes through the relay optical system 5 and forms an image on the image sensor 12.
At this time, the shutter 15 is kept open by the shutter opening / closing mechanism 16 and the opening of the secondary mirror 2 is opened.
The light can be focused to one.

Embodiment 2 FIGS. 2 and 3 show one means for switching the visual field. Hereinafter, a second embodiment of the multi-field optical device according to the present invention will be described with reference to FIGS. In FIG. 2, reference numerals 1 to 5 and 8 to 15 denote portions having the same functions as the same-numbered portions shown in FIG. 1. The visual field switching unit 13 is supported by a visual field switching unit support member 17, and is guided via a bearing 19 by a guide shaft 18. The bearing 19 can move in the axial direction along the guide shaft 18. Reference numeral 20 denotes a block, 21 denotes a switch member, 22 denotes a lever member, and 23 denotes a spring member. FIG. 3 shows the same configuration as in FIG.
It is a figure shown in somewhat detail. 3 up to 23 in FIG.
The same parts are shown. 24 is a roller, 25 is a support shaft, 26
Is a connecting portion, 27 is a pin, 28 is an opening of the secondary mirror, 29 is a shutter rotating shaft, and 30 and 31 are spring stoppers.

The multi-field optical device according to the present invention is configured as described above and operates as follows. When a signal indicating a narrow visual field is output from the visual field selecting device 8, the visual field switching unit 13 moves to the object side in the optical axis direction along the guide shaft 18 and stops at the stop position of the narrow visual field, and the narrow visual field light flux 9
Is focused once at an intermediate image point 11 by a narrow-field reflective objective optical system 3 composed of a primary mirror 1 and a secondary mirror 2, passes through a relay optical system 5, and forms an image on an image sensor 12. At this time, the shutter is closed by the operation of the lever member 21 and the switch member 22. Referring to FIG. 3, the movement of the components of the present invention will be described. When the visual field switching unit reaches a narrow visual field position, a roller 24 attached to the tip of the switch member 21 hits the block 20 and moves on the slope. Compete.
The switch member rotates around the support shaft 25, pulls the lever member connected by the connecting portion 26, and pulls up the shutter via the pin 27 attached to the shutter. The shutter 15 rotates around a rotation axis 29 of the shutter and shields the opening 28 of the secondary mirror.

On the other hand, when a signal for instructing a wide field of view is output from the field of view selecting device 8, the field of view switching unit 13
8 moves to the image side in the optical axis direction, stops at the stop position of the wide field of view, and the wide field light beam 10 passes through the wide field objective optical system 4 and is once condensed on the intermediate image forming point 11 and relay optical. The light passes through the system 5 and forms an image on the image sensor 12. At this time, the shutter 15 is kept open by the action of the spring member 23. The movement of the components of the present invention will be described with reference to FIG. 3. When the visual field switching unit moves away from the narrow visual field position, the elastic force of the spring member 23 acts between the spring stoppers 30 and 31, and the shutter 15 is rotated. Rotation about the axis 29 opens the secondary mirror opening 28.

Embodiment 3 FIG. 4 is also a view showing one means for switching the visual field. Hereinafter, a third embodiment of the multi-field optical device according to the present invention will be described with reference to FIG. In the figure, 1-5, 8-15, 17
Reference numerals 19 to 19 denote portions having the same functions as the same numbered portions given in the first embodiment, 32 denotes one end fixed to the shutter 15 by a wire, and the other end extends in the longitudinal direction of the guide shaft 18 via the pulley 33. Guided and fixed to the fixed part. Reference numeral 34 denotes a spring, one end of which is fixed to the visual field switching unit 13 and the other end of which is fixed to the shutter 15, which constantly applies a pulling force so that the wire 32 does not slack.

The multi-field optical device according to the present invention is configured as described above and operates as follows. When a signal for instructing a narrow visual field is issued from the visual field selecting device 8, the visual field switching unit 13 moves to the object side in the optical axis direction along the guide shaft 18 as in the case of the second embodiment, and moves to the stop position of the narrow visual field. After stopping, the narrow-field light beam 9 is once focused at the intermediate image point 11 by the narrow-field reflective objective optical system 3 composed of the primary mirror 1 and the secondary mirror 2.
The light passes through the relay optical system 5 and forms an image on the image sensor 12.
At this time, the wire 32 is connected to the guide shaft 18 by the pulley 33.
, The shutter 15 can be pulled to shield the opening with a wide field of view.

On the other hand, when a signal for instructing a wide field of view is output from the field of view selecting device 8, the field of view switching unit 13
8 moves to the image side in the optical axis direction, stops at the stop position of the wide field of view, and the wide field light beam 10 passes through the wide field objective optical system 4 and is once condensed on the intermediate image forming point 11 and relay optical. The light passes through the system 5 and forms an image on the image sensor 12. At this time, the spring 34
Pulls the shutter 15, and the shutter 15 is kept open.

Embodiment 4 Hereinafter, an embodiment 4 of the multi-field optical device according to the present invention will be described.
Will be described with reference to FIG. In the figure, 1-5, 8-15, 1
Reference numerals 7 to 19 and 28 denote portions having the same functions as the same-numbered portions given in Embodiment 1, 35 denotes an optical plate with a shield, 3
Reference numeral 6 denotes a shield provided on the shielded optical plate 35, which may be a thin film such as a paint. 37 is a transmission optical plate without shielding. Numeral 38 denotes an optical plate rotating plate and an optical plate 35 with a shield.
And a transmission optical plate 37. The optical plate rotating plate 38 is rotatably fitted to a rotating plate rotating shaft 39. Reference numeral 40 denotes an optical plate switching device.

The multi-field optical device according to the present invention is configured as described above and operates as follows. When a signal for instructing a narrow visual field is issued from the visual field selecting device 8, the visual field switching unit 13 moves to the object side in the optical axis direction along the guide shaft 18 as in the case of the second and third embodiments, and stops the narrow visual field. After stopping at the position, the narrow-field light flux 9 is once collected at the intermediate image point 11 by the narrow-field reflective objective optical system 3 composed of the primary mirror 1 and the secondary mirror 2, passes through the relay optical system 5, and passes through the imaging element 12. Image on top. The signal indicating the narrow visual field from the visual field selecting device 8 is also sent to the optical plate switching device 40 at this time, and at this time, the optical plate rotating plate 38 is rotated by the signal from the optical plate switching device 40, and is blocked on the optical axis. Optical plate 35 is inserted. The shield 36 provided on the shielded optical plate 35 is a relay optical system 5.
Is conjugate with the aperture 28 of the secondary mirror, an image of the aperture 28 of the secondary mirror is formed on the shielded optical plate 35, and the aperture 36 of the secondary mirror is formed at a position overlapping the image.
Are all shielded and do not reach the image sensor 12.

On the other hand, when a signal indicating a wide field of view is output from the field of view selecting device 8, the field switching unit 13
8 moves to the image side in the optical axis direction, stops at the stop position of the wide field of view, and the wide field light beam 10 passes through the wide field objective optical system 4 and is once condensed on the intermediate image forming point 11 and relay optical. The light passes through the system 5 and forms an image on the image sensor 12. At this time, the optical plate rotating plate 38 is rotated by a signal from the optical plate switching device 40, and the transmission optical plate 37 is inserted on the optical axis. Since the transmission optical plate 37 has no shielding, it transmits through the wide-field optical system 4,
All the light fluxes that have passed through the aperture 28 of the secondary mirror reach the image sensor 12 and form a wide-field image.

Fifth Embodiment Hereinafter, a fifth embodiment of the multi-field optical device according to the present invention will be described.
Will be described with reference to FIG. FIG. 6C shows the optical plate rotating plate according to the present invention viewed from the front in the direction in which light rays enter. The fifth embodiment of the multi-field optical device according to the present invention is such that, in addition to the shielded optical plate 35 and the transmission optical plate 37 on the optical plate rotating plate 38, the shielded optical filter 41, the unshielded optical filter 42, and the filter selection device are provided. The configuration is the same as that of the fourth embodiment shown in FIG.

The multi-field optical device according to the present invention is configured as described above and operates as follows. Similar to the optical device of the fourth embodiment, the multi-field optical device according to the present invention moves the visual field switching unit 13 to the object side in the optical axis direction, rotates the optical plate rotating plate 38 by a signal from the optical plate switching device 40, It is shielded by a shield 36 conjugate with the opening 28 of the secondary mirror. On the other hand, in the wide field of view, the transmission optical plate 37 is placed on the optical axis.
Into the image pickup device 1
2 to form a wide-field image.

Further, in the multi-field optical device according to the present invention, in addition to the shielded optical plate 35 and the transmission optical plate 37 on the optical plate rotating plate 38, the shielded optical filter 41, the unshielded optical filter 42, and the filter selection A device 43 is provided. The shielded optical filter 41 and the unshielded optical filter 42 are provided with an optical film that transmits a specific wavelength band. It is now assumed that the optical plate 35 with a shield has a narrow visual field on the optical axis. When a signal for instructing the filter to "enter" is output from the filter selection device 43, the optical plate rotating plate 38 is rotated 90 degrees counterclockwise by the optical plate switching device 40, and the shielded filter 41 is arranged on the optical axis. .
Conversely, when a signal indicating a filter "OFF" is issued from the filter selection device 43, the optical plate rotating plate 38 is rotated 90 degrees clockwise by the optical plate switching device 40, and the shielded filter 35 is placed on the optical axis. Let it be placed. Similarly, in the wide field of view, the transmission optical plate 37 and the non-shielding optical filter 42 are switched. When the field of view is switched, the optical plate rotating plate 38 may be rotated by 180 degrees regardless of whether the filter is "ON" or "OFF".

[0027]

Since the present invention is configured as described above, it has the following effects.

According to the first aspect of the present invention, when the narrow field of view image is formed, the shielding means for blocking the aperture is provided, so that light irrelevant to the image obtained through the aperture from outside is provided. As a result, it is possible to prevent fogging on the surface of the image pickup device, reduction in image contrast, and ghost due to the imaging action of the wide-field objective optical system. Conventionally, avoiding such a problem has been a major constraint in design, but the configuration described in the present invention can greatly expand the degree of freedom in design.

According to the second aspect of the present invention, the sub-mirror provided with the aperture and the wide-field objective optical system are integrated into a field switching unit, and the field switching unit is moved in the optical axis direction to switch the field of view. By providing a shutter and a plate member for blocking unnecessary openings in the field of view and a shutter for the wide field of view, the openings can be blocked in a narrow field of view without having an independent drive system as a shutter opening / closing device. As a result, it is possible to prevent fogging of light irrelevant to the desired image formation on the image pickup device surface, decrease in image contrast, and ghost due to the image forming action of the wide-field objective optical system. Can be greatly expanded.

According to the third aspect of the present invention, a sub mirror provided with an aperture and a wide-field objective optical system are integrated into a field switching unit, a device for moving the field switching unit in the optical axis direction, and a narrow field of view. A shutter for blocking the opening when forming an image, a wire for blocking the opening in a narrow field of view and pulling the shutter in a narrow field of view, and a spring member for pulling the shutter in the opposite direction in a wide field of view and returning the shutter to its original position are provided. Thus, the aperture can be blocked in a narrow visual field without having an independent drive system as a shutter opening / closing device. As a result, it is possible to prevent fogging of light irrelevant to the desired image formation on the image pickup device surface, decrease in image contrast, and ghost due to the image forming action of the wide-field objective optical system. Can be greatly expanded.

According to the fourth aspect of the present invention, there is provided an apparatus for integrating a secondary mirror provided with an aperture and a wide-field objective optical system into a field switching unit, moving the field switching unit in the optical axis direction, and a relay optical system. By providing an optical plate having a shielding portion at a position conjugate to the aperture stop with respect to the system and providing an optical plate switching device for switching to an unshielded optical plate by a signal of a narrow or wide field of view, unnecessary in a narrow field of view. Can be blocked. As a result, it is possible to prevent fogging of light irrelevant to the desired image formation on the imaging element surface, decrease in image contrast, and ghost due to the image forming action of the wide-field objective optical system.
The degree of freedom in design can be greatly expanded.

According to the fifth aspect of the present invention, there is provided an apparatus for integrating a sub-mirror provided with an opening and a wide-field objective optical system into a field switching unit, moving the field switching unit in the optical axis direction, and a relay optical system. By providing an optical plate having a shielding portion at a position conjugate to the aperture stop with respect to the system and providing an optical plate switching device for switching to an unshielded optical plate by a signal of a narrow or wide field of view, unnecessary in a narrow field of view. Can be blocked. Furthermore, the use and non-use of the filter can be switched by the same mechanism, and as a result, the degree of freedom in design can be greatly expanded.

[Brief description of the drawings]

FIG. 1 is a first embodiment of a multi-field optical device according to the present invention;
FIG.

FIG. 2 is a second embodiment of the multi-field optical device of the present invention.
FIG.

FIG. 3 is a second embodiment of the multi-field optical device of the present invention.
FIG. 4 is a diagram showing a shutter opening / closing mechanism of FIG.

FIG. 4 is a third embodiment of the multi-field optical device of the present invention.
FIG.

FIG. 5 is a fourth embodiment of the multi-field optical device of the present invention.
FIG.

FIG. 6 is a fifth embodiment of the multi-field optical device of the present invention.
FIG.

FIG. 7 is an embodiment of a conventional multi-field optical device.

FIG. 8 is an embodiment of a conventional multi-field optical device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Primary mirror 2 Secondary mirror 3 Narrow-field reflective objective optical system 4 Wide-field objective optical system 5 Relay optical system 6 Secondary-mirror support member 7 Wide-field objective optical system driving device 8 Field-of-view selecting device 9 Narrow-field light beam 10 Wide-field light beam 11 Intermediate Image forming point 12 Image sensor 13 Field switching unit 14 Field switching unit moving device 15 Shutter 16 Shutter opening / closing mechanism 17 Field switching unit support member 18 Guide shaft 19 Bearing unit 20 Block 21 Switch member 22 Lever member 23 Spring member 24 Roller Reference Signs List 25 support shaft 26 connecting portion 27 pin 28 opening of sub-mirror 29 rotation axis of shutter 30 spring stop 31 spring stop 32 wire 33 pulley 34 spring 35 shielded optical plate 36 shield 37 transmission optical plate 38 optical plate rotating plate 39 optical Plate rotation axis 40 Optical plate switching device 41 Optical filter with shield 42 Unshielded The optical filter 43 filter selection device

Claims (5)

[Claims] When a narrowest field of view is a narrow field of view and another field of view is a wide field of view of a multi-field optical device which can be switched to two or more viewing angles, it is constituted by a primary mirror and a secondary mirror. A narrow-field reflective objective optical system, a relay optical system for re-focusing the light beam focused by the narrow-field reflective objective optical system at an intermediate image point on a subsequent detection element and forming an image, An opening provided in the sub-mirror for the passage of the light beam, and a wide-field objective optical element for imaging the light beam passing through the opening and entering from the outside at the same position as the intermediate image point of the narrow-field reflection objective optical system In a multi-field optical device having a system,
A multi-field optical device comprising: means for blocking the aperture when forming a narrow-field image. 2. A shutter for blocking the opening when forming an image in a narrow field of view, a plate member for pulling the shutter in a narrow field of view and blocking the opening, and pulling the shutter in the opposite direction in a wide field of view. 2. The multi-field optical device according to claim 1, further comprising a spring member for returning to an original position. A shutter for blocking the opening when forming an image in a narrow field of view, pulling the shutter in a narrow field of view and a wire for blocking the opening, and pulling the shutter in the opposite direction in a wide field of view; The multi-field optical device according to claim 1, further comprising a spring member that returns to an original position. 4. An optical plate placed at a position conjugate with the aperture stop with respect to a relay optical system, and the optical plate for blocking a light beam passing through the aperture when forming a narrow-field image. 2. The multi-field optical device according to claim 1, further comprising: a shielding portion provided on the plate, and an optical plate switching device for moving the optical plate to a position where the light flux of a wide field of view is not blocked by an external command. 5. The multi-field optical device according to claim 4, wherein an optical film for blocking a specific wavelength band is provided on an optical plate having a blocking portion for blocking the opening.