JP3272634B2 - Camera viewfinder device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a finder device for a camera, and more particularly to a finder device provided independently of a photographic lens system.

[0002]

2. Description of the Related Art Recent cameras, whether a single-lens reflex camera or a compact camera, generally have an autofocus function. With a single-lens reflex camera, the degree of blurring of the image formed on the focus plate in the viewfinder changes with the focusing of the shooting lens, and as a result of autofocusing, it is determined whether or not the subject is in focus by looking at the viewfinder can do.

On the other hand, in a camera in which the finder system is provided independently of the photographing lens system, means for turning on a lamp in the finder when the subject distance can be detected is provided. When lights up, it is determined that the subject is in focus and the shutter is released.

[0004]

However, in a non-single-lens reflex camera, it is not possible to confirm whether or not the photographer can properly focus on the subject intended by the photographer before photographing. If the camera is set to autofocus without accurately focusing on the subject, or if the subject malfunctions because it is difficult to detect flames or scenery through glass by the distance measurement system, the intended subject will be in focus. There is a problem that does not fit.

That is, since the means such as the lamp in the finder only indicates whether or not the distance measurement has been successful for the subject located in the distance measurement area, the above-mentioned operation by the photographer is performed. In the event of a mistake or malfunction of the distance measurement system, a so-called out-of-focus photograph is taken without focusing on the subject intended by the photographer, even if the photographer confirms that the lamp is on. The Rukoto.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems of the prior art. In a camera in which a finder system is provided independently of a photographic lens system, the camera focuses on a subject intended by a photographer by autofocusing. It is an object of the present invention to provide a finder device that allows the user to know whether or not the camera can be adjusted while looking at the finder.

[0007]

To achieve the above object, a finder apparatus according to the present invention has a first objective optical system for forming a virtual image of a subject and a first objective optical system having a predetermined base line length. A second objective optical system that looks at the subject from a direction different from that of the subject and forms a real image of the subject;
An upright optical system for inverting an inverted image formed by the objective optical system to form an erect image, and a part of a visual field formed by a light beam incident through the first objective optical system;
A light beam combining element that forms a double image by superimposing light beams incident through the second objective optical system and the erecting optical system, and an eyepiece optical system that guides the light beam combined by the light beam combining device to the photographer's eyes An optical path deflecting means for deflecting the optical path of the second objective optical system to change the degree of overlap of the double images along the base line length direction; Active means for detecting a distance to a subject, including a light-collecting frame display means for combining with a light beam incident through the first objective optical system or the second objective optical system by a mirror, and a light projecting system and a light receiving system. And two object images formed by light beams incident from the first and second objective optical systems on the object at the object distance based on the object distance detected by the distance measuring means. Heavy And a control means for controlling so that the light path deflecting means. The light projecting system emits the detection light to the object side through the display half mirror and the lighting window in order, and the light receiving system emits the light from the light projecting system via the optical path deflecting means and is reflected by the object. Receiving the detected light. Further, the light projecting system can project the detection light toward the subject via the light beam combining element and at least a part of the lenses of the first objective optical system in this order.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an embodiment of a finder device for a camera according to the present invention will be described. FIG. 1 is an explanatory diagram illustrating a configuration of an optical system and a control system of the finder device according to the embodiment. The photographic optical system is provided independently of the finder, and has an autofocus function in which the photographic lens is driven for focusing according to a subject distance signal from a distance measuring device.

The optical system of the double image matching type finder according to the embodiment comprises a virtual image type finder optical system, a real image type rangefinder optical system, and an active type distance measuring means. The finder optical system includes a first objective optical system 10 for forming a virtual image of a subject and an eyepiece lens (eyepiece optical system) 50, and constitutes an inverse Galilean finder. The first objective optical system 10 includes a negative lens 11 and a positive lens 12.

The rangefinder optical system includes a second objective optical system 20 for forming a real image of a subject by a light beam reflected by the rotating mirror 40, a condenser lens 23, and a relay lens 24. The second objective optical system 20 includes a negative lens 21 and a positive lens 22. The second objective optical system 20 differs from the first objective optical system 10 with a predetermined base line length by viewing a subject via the rotating mirror 40. Look at the subject from the direction. The inverted image formed by the second objective optical system 20 is re-imaged by the relay lens 24, which is an erecting optical system, to be an erect image. The range of the image formed by the rangefinder optical system is limited only to the central portion of the finder field of view by a stop (not shown) arranged near the image plane IM of the second objective optical system 20.

A light beam incident through the first and second objective optical systems 10 and 20 is converted into a half mirror 30 as a light beam combining element disposed between the first objective optical system 10 and the eyepiece 50. Are synthesized by First objective optical system 10
Incident on the finder cover the entire area of the finder field of view, a part of which passes through the half mirror 30, and is guided to the photographer's eye via the eyepiece lens 50. On the other hand, a light beam incident from the second objective optical system 20 has a transmission range limited to a central portion in the finder visual field by a stop, and a part of the light beam is reflected by the half mirror 30 and is reflected by the photographer Incident on. Therefore, the photographer can use the two objective optical systems 10 and 20 for the range in the center of the viewfinder.
Observes a double image formed by the light beam incident through the first objective optical system 10, and observes a non-overlapping image formed by the light beam incident through the first objective optical system 10. Can be.

The degree of overlapping of the double images is changed by changing the angle of the rotating mirror 40 according to the output of the distance measuring means. The angle of the rotating mirror 40 is controlled by a mirror driving motor 110 which is a stepping motor. The rotating mirror 40 and the mirror driving motor 110 deflect the optical path of the second objective optical system 20, that is, the second objective optical system Ax1 with respect to the optical axis Ax1 of the first objective optical system 10. By tilting the optical axis Ax2 of the system 20, it functions as an optical path deflecting unit that changes the degree of overlap of the double images along the base line length direction. As the optical path deflecting means, in addition to using the above-mentioned rotating mirror 40, at least a part of the lens of the second objective optical system 20 is connected to the second objective optical system 2.
A mechanism for eccentricity in the direction perpendicular to the optical axis 0 may be provided, or a variable apex angle prism may be used.

The active distance measuring means includes a light projecting system 60 having an infrared light emitting diode 61 and a light projecting lens 62.
And a light receiving system 70 including a light receiving lens 71 and a PSD element 72. The light projecting system 60 combines the detection light with the optical path of the first objective optical system 10 by using a half mirror for light projection, and projects the light toward the subject through at least a part of the lenses of the first objective optical system 10. Light. In this example, the light projecting half mirror is also used as the half mirror 30 as a light beam combining element. That is, the light projecting system 60 is arranged so that the detection light enters the half mirror 30 from the opposite side of the second objective optical system 20, and the detection light reflected by the half mirror 30 is the first light. The light is projected on the subject side through two lenses of the objective optical system 10.

The light receiving system 70 separates the optical path of the range finder optical system from the second objective optical system 20 by a light receiving half mirror disposed on the object side in the optical path of the range finder optical system, thereby providing a light projecting system. The detection light emitted from 60 and reflected by the subject is received. In this example, the light receiving half mirror is also used as the rotating mirror 40 which is an optical path deflecting unit. The rotating mirror 40 can be configured as a dichroic mirror that transmits infrared light and reflects visible light. The detection light transmitted through the rotating mirror 40 is condensed on the PSD element 72 via the light receiving lens 71.

The PSD element 72 is an element that detects the center position of the intensity distribution of the collected light as a resistance value. The control circuit 100 obtains a subject distance based on the principle of triangulation by reading, as a resistance value, a condensing position of the detection light that changes according to the distance to the subject. Also, the control circuit 1
00 is a turning mirror 4 based on the calculated subject distance.
A rotation angle of 0 is obtained. The angle of the rotating mirror 40 is such that two subject images formed by the light beams incident from the first and second objective optical systems 10 and 20 on the subject at the calculated subject distance are within the double image forming range. To match
That is, the optical axis Ax1 of the first objective optical system 10 and the optical axis Ax2 of the second objective optical system are determined to intersect at the detected object distance. The control circuit 100 controls the mirror drive motor 110 so that the turning mirror 40 is set at the obtained turning angle.

The subject distance information output from the distance measuring means is generally used by an autofocus device that automatically focuses the photographing lens on the subject. In this embodiment, the rotation of the rotating mirror 40 is performed as described above. The subject distance information is also used as information for determining the moving angle. Thus, it is possible to know whether or not the subject intended by the photographer is focused by the autofocus while looking through the viewfinder. In other words, according to the finder device of the embodiment, the rotating mirror 4 is moved so that the image of the subject to be measured for distance can be observed in the double image forming range.
Since 0 is controlled, if it is a subject intended by the photographer, it can be determined that the intended subject can be focused by the auto focus, and the image of the intended subject is shifted in the double image display area and doubled. When the subject is observed, it is understood that the intended subject is different from the subject to be measured. Therefore, when the image of the intended subject is double-observed, the photographing lens can be focused on the intended subject by re-measuring the distance until the image of the intended subject is observed.

Further, in this embodiment, a frame display means 80 for displaying a bright frame in the field of view is provided, and the finder optical system is configured as a lighting type bright frame finder. The frame display means 80 uses a display half-mirror 83 to display light that has been transmitted through the frame mask 81 and the condenser lens 82 from a lighting window provided in the middle of the window for capturing a light beam into each of the objective optical systems 10 and 20 by the display half mirror 83. Objective optical system 20
Is combined with the light beam incident through the.

The frame mask 81 is formed by forming a linear transparent portion for displaying a bright frame (optical image frame) on an opaque plate, and is formed with the image plane IM of the second objective optical system 20. They are arranged at optically equivalent positions. The display light combined by the display half mirror 83 disposed between the condenser lens 23 and the relay lens 24 is reflected by the half mirror 30 together with the light beam incident through the second objective optical system 20, and is connected to the eyepiece. It is incident on 50. The photographer sets the frame mask 81 in the visual field including the above-described double image.
Can be viewed in an overlapping manner.

The present invention is not limited to the above embodiment, and the following modifications are possible. Floodlight system 60
Not only emits the display light through the first objective optical system 10 as in the embodiment, but also provides a light projection system at a position facing the frame mask 81 with respect to the display half mirror 83, and May be configured to project the detection light to the subject side through a transmission portion provided at the center of the object.

Further, the frame display means 80 may be constructed not only in the daylighting type as in the above embodiment but also in an Albada type finder. In the case of the Albada type, for example, the negative lens 11 of the first objective optical system 10
A field frame plate is formed with a metal mask in opposition to the inner surface of the negative lens 11, and a virtual image resulting from the reflection of the field frame can be reflected on the inner surface of the negative lens 11 for observation.

Further, when the photographing optical system is constituted by a variable-magnification lens such as a zoom lens, it is desirable that the first and second objective optical systems 10 and 20 are also constituted as a variable-magnification optical system. In this case, the magnification of the first objective optical system 10 is changed according to the change in the focal length of the photographing optical system, and the second magnification is made equal to the magnification of the first objective optical system 10.
It is desirable to provide a magnification changing means for changing the magnification of the objective optical system 20.

[0022]

As described above, according to the present invention, a double image can be used as a means for confirming an autofocus function, and even in a camera in which a finder system is provided independently of a photographic lens system. Since it is possible to know whether or not the subject intended by the photographer is in focus before photographing, it is possible to prevent a photographing error relating to focusing in advance.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram of an optical system and a control system showing an embodiment of a camera finder device according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 1st objective optical system 20 2nd objective optical system 30 Half mirror (light beam combining means) 40 Rotating mirror (optical path deflecting means) 50 Eyepiece 60 Light projecting system 70 Light receiving system 80 Frame display means 100 Control circuit 110 Mirror Drive motor

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-6-18961 (JP, A) JP-A-9-15686 (JP, A) JP-A-8-18857 (JP, A) JP-A-7- 113947 (JP, A) Fully open, 55-118223 (JP, U) Fully open, 54-135529 (JP, U) Fully open, 49-108430 (JP, U) Fully open, 58-172917 (JP, U) Japanese Patent Publication No. 35-1473 (JP, B1) Japanese Utility Model Publication No. 42-12549 (JP, Y1) (58) Fields investigated (Int. Cl. ⁷ , DB name) G03B 13/02-13/36 G02B 7/32

Claims (11)

(57) [Claims] In a finder device of a camera provided independently of a photographing optical system, a first objective optical system for forming a virtual image of a subject and a first objective optical system having a predetermined base length are provided. A second objective optical system for viewing the subject from different directions and forming a real image of the subject; and erecting optics for forming an erect image by inverting an inverted image formed by the second objective optical system. By superimposing a light beam incident through the second objective optical system and the erecting optical system on a part of a field formed by a light beam incident through the first objective optical system. A light beam combining element that forms a double image; an eyepiece optical system that guides a light beam combined by the light beam combining element to a photographer's eye; and the double image by deflecting an optical path of the second objective optical system. The overlap condition of the baseline An optical path deflecting means for changing along the longitudinal direction; and light incident from a lighting window and transmitted through a frame mask is incident on the display objective half mirror via the first objective optical system or the second objective optical system. A daylighting type frame display unit for synthesizing with a light beam, an active type distance measuring unit including a light projecting system and a light receiving system, and detecting a distance to the object, based on the object distance detected by the distance measuring unit. Control means for controlling the optical path deflecting means so that two object images formed by the light beams incident from the first and second objective optical systems on the object at the object distance overlap each other. The light system emits the detection light to the subject side through the display half mirror and the lighting window in this order, and the light receiving system emits the light from the light projection system via the optical path deflecting means. Camera finder, characterized in that for receiving the detection light reflected by the body. 2. A finder device for a camera provided independently of a photographing optical system, comprising: a first objective optical system for forming a virtual image of a subject; and a first objective optical system having a predetermined base line length. A second objective optical system for viewing the subject from different directions and forming a real image of the subject; and erecting optics for forming an erect image by inverting an inverted image formed by the second objective optical system. By superimposing a light beam incident through the second objective optical system and the erecting optical system on a part of a field formed by a light beam incident through the first objective optical system. A light beam combining element that forms a double image; an eyepiece optical system that guides a light beam combined by the light beam combining element to a photographer's eye; and the double image by deflecting an optical path of the second objective optical system. The overlap condition of the baseline An optical path deflecting means for changing along the longitudinal direction; an active type distance measuring means comprising a light projecting system and a light receiving system for detecting a distance to the object; and an object distance detected by the distance measuring means. Control means for controlling the optical path deflecting means so that two subject images formed by the light beams incident from the first and second objective optical systems on the subject located at the subject distance overlap. The light projecting system projects the detection light to the subject side through the light beam combining element and at least a part of the lens of the first objective optical system in order, and the light receiving system passes through the optical path deflecting unit. A camera finder device for receiving detection light emitted from the light projecting system and reflected by the subject. 3. The finder device for a camera according to claim 2, wherein the light beam combining element is disposed between the first objective optical system and the eyepiece optical system. 4. The camera according to claim 2, further comprising frame display means for displaying a bright frame in the field of view, wherein the camera is configured as a daylighting type bright frame finder. Viewfinder device. 5. The frame display means is a light beam that enters light from a lighting window and passes through a frame mask through a first objective optical system or a second objective optical system by a display half mirror. The viewfinder device for a camera according to claim 1, wherein the viewfinder device is combined with the camera. 6. The camera viewfinder according to claim 1, wherein the display half mirror is disposed between the second objective optical system and the light beam combining element. apparatus. 7. The camera viewfinder according to claim 1, wherein the frame mask is disposed at a position optically equivalent to an image forming plane of the second objective optical system. apparatus. 8. The camera according to claim 2, further comprising frame display means for displaying a bright frame in the field of view, wherein the camera is configured as an albada-type bright frame finder. Viewfinder device. 9. A magnification of the first objective optical system is changed in accordance with a change in a focal length of the photographing optical system, and the second objective optical is set to be equal to a magnification of the first objective optical system. 9. The finder device for a camera according to claim 1, further comprising a scaling unit for changing a magnification of the system. 10. The optical path deflecting means includes a rotating mirror,
10. The viewfinder device for a camera according to claim 1, further comprising: mirror driving means for rotating the rotating mirror. 11. The camera viewfinder device according to claim 10, wherein the rotating mirror is a dichroic mirror that transmits infrared light and reflects visible light.