JPS63253928A - Object image type finder system - Google Patents

Abstract

PURPOSE:To adjacently place a display frame and a visual field frame, to miniaturize a normally erecting image prism, and to improve the finder magnification, by providing a reflecting surface on the outside peripheral part of a condenser lens, and illuminating the display frame by utilizing this reflecting surface. CONSTITUTION:An illuminating light from a light emitting means 8 placed in the vicinity of an objective lens system illuminates a display frame 4 provided in the vicinity of an image forming surface of the objective lens system, through a reflecting surface 10 provided on the outside peripheral part of a condenser lens 1, and by an eyepiece 3, the display frame 4 is observed together with a finder image. In such a way, the display frame 4 and a visual field frame 5 can be brought close to each other, a side of the whole normally erecting image prism 2 can be miniaturized, and also, the focal distance of the eyepiece system 3 can be shortened.

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to a real-image finder system, and in particular uses an erect image prism to observe a display frame displaying shooting mode, exposure information, etc. together with the finder image. This relates to a real image finder system.

(Prior Art) Conventionally, one method of displaying information in the finder in a real image finder system is to illuminate the display frame containing the information in the finder provided on an erecting image prism directly using a light source such as an LED. There is a way. FIG. 3 is a schematic diagram of an example of a finder system illustrating the method. In the figure, 31 is a condenser lens, 32 is an erecting image prism, 33 is an eyepiece system, 34 is a display frame, 35 is a viewfinder field frame, 36 is an optical axis of the finder observation system, and 38 is an illumination device such as an LED. , 11 are the ends of the LED board. The information in the viewfinder is erected using the erect image prism 3.
The display frame 34 is directly illuminated by an illumination device 38 such as an LED and guided to an observation pupil (not shown) together with the finder observation light flux. However, the light source part of the lighting device 38 such as an LED cannot be provided at the extreme end of the LED board, and the end part 11 of the LED board is required for reasons such as obtaining installation strength for attaching the light source part to the board. However, since the display frame 4 is directly illuminated by an illumination device 38 such as an LED, the display frame 34 is used as the viewing frame 35.
If you try to move it closer to the LED board, the end 11 of the LED board will come into the viewfinder field of view. Therefore, the display frame 34 must be placed at a certain distance from the viewing frame 35 in the direction perpendicular to the optical axis.

In particular, in a real-image finder system, the finder field image is relatively small, so as the display frame 34 moves away from the field frame 35 in the direction perpendicular to the optical axis, the erecting image prism 32 becomes larger, and the focal point of the eyepiece lens system becomes larger. The finder magnification tends to decrease as the distance increases.

Another method for displaying information in the finder is to optically superimpose the image of the display frame on the image of the field frame, and FIG. 4 is a schematic diagram of a finder system showing this method. It is. In the figure, the same members as in Figure 3 are given the same numbers, and 47 is the center of the luminous flux of the display frame image;
A small prism 49 is connected to a part of the erect image prism 32. From the side of the erect image prism 32, L
The display frame 34 is illuminated by a lighting device 38 such as an ED. The luminous flux of the display frame image enters the erecting regular image prism 32 via the small prism 49, and is then optically superimposed on the image of the field frame 35 when exiting the erecting regular image prism 32.

However, as described above, in order to superimpose the image of the field frame 35 and the image of the display frame 34 to form a viewfinder observation image, the positions of the field frame 35 and the display frame 34 must be set to a high degree of granularity. This has resulted in drawbacks such as the requirement for precise machining accuracy of the erecting image prism 32 and the small prism 49.

(Problems to be Solved by the Invention) The present invention provides a so-called external measurement type real image finder system in which an erecting regular image prism is disposed between an objective lens system and an eyepiece system, in which a display frame and a field frame are placed close to each other. To provide a real image finder system of a simple configuration that can be arranged and that does not make the positional accuracy of a display frame and a field frame and the processing accuracy of an erecting image prism excessively strict.

(Means for solving the problem) In an external type real image finder system in which an erecting regular image prism is placed between an objective lens system having a condenser lens and an eyepiece system, the prism is placed near the objective lens system. The illumination light from the light emitting means illuminates a display frame provided near the imaging plane of the objective lens system through a reflective surface provided on the outer periphery of the condenser lens, and the display frame is illuminated by the eyepiece through the viewfinder. The idea was to observe it together with the image.

(Embodiment) FIGS. 1 and 2 are schematic diagrams showing an embodiment of the present invention, with FIG. 1 being a side view and FIG. 2 being a perspective view. Same 1.2
In the figure, 1 is a condenser lens, 2 is an erecting prism, 3 is an eyepiece system, 4 is a display frame that displays shooting mode, exposure information, etc., 5 is a field frame that shows the range of the shooting field,
6 is the optical axis of the finder observation system, 7 is the center of the luminous flux of the display frame image, 8 is a light emitting means such as an LED, and 10 is a reflective surface provided on the outer periphery of the condenser lens 1.

The illumination light from the light emitting means 8 is reflected by the reflective surface 10 of the condenser lens 1 to illuminate the display frame 4.

The light beam from the illuminated display frame 4 passes through the erecting image prism 2 and the eyepiece lens system 3, reaches an observation pupil (not shown), and displays information in the finder such as exposure information.

Note that the reflective surface 10 provided on the outer periphery of the condenser lens 1
It is preferable to finish the mirror surface with a vapor-deposited aluminum film or with an aluminum reflective material.

In this embodiment, when the display frame 4 is directly illuminated by the light emitting means 8 such as an LED as in the method shown in FIG. 3, the display frame 4 and the viewing frame 5 are Although they were separated, the display frame 4 and the field of view frame 5 can be brought closer to each other by that much.

Therefore, the overall size of the erecting image prism 2 can be reduced, the focal length of the eyepiece system can be shortened, and the finder magnification can be improved.

In addition, since the configuration is simple in that the illumination light from the light emitting means 8 is reflected by the reflective surface provided on the outer periphery of the condenser lens 1 to illuminate the display frame 4, accurate illumination and reflection can be performed.
In addition, high positional accuracy of each member can be obtained relatively easily in order to obtain an accurate positional relationship between the display frame 4 and the viewing field frame 5.

(Effects of the Invention) According to the present invention, by providing a reflective surface on the outer periphery of the condenser lens and illuminating the display frame using the reflective surface, the display frame and the viewing frame can be placed close to each other. To achieve a real image finder system in which the magnification of the finder can be improved along with the miniaturization of the erecting image prism, and in which high positional accuracy of each member can be obtained relatively easily due to the simple configuration. Can be done.

[Brief explanation of drawings]

1 and 2 are schematic diagrams showing one embodiment of the present invention, with FIG. 1 being a side view and FIG. 2 being a perspective view. FIG. 3 is an explanatory diagram of a conventional example in which the display frame is directly illuminated, and FIG. 4 is an explanatory diagram of a conventional example in which the display frame and the field of view frame are overlapped. In the figure, 1 is a condenser lens, 2 is an erect image prism, 3 is an eyepiece system, 4 is a display frame, 5 is a field frame, 6 is the optical axis of the finder observation system, and 7 is the center of the illumination light flux of the display frame. , 8 is a light emitting means such as an LED, 49 is a small prism, 10
is the reflective surface provided on the condenser lens 1, and 11 is the LED
This is the edge of the board. Patent applicant: Canon Co., Ltd. Higashi 1 Figure 2 Figure 4 Figure 4

Claims (1)

[Claims] In an external type real image finder system in which an erecting regular image prism is arranged between an objective lens system having a condenser lens and an eyepiece lens system, illumination light from a light emitting means arranged near the objective lens system is transmitted to the condenser lens system. A display frame provided near the imaging plane of the objective lens system is illuminated through a reflective surface provided on the outer periphery of the lens, and the display frame is observed together with the finder image through the eyepiece. Real image finder system.