JP3170727B2 - Daylighting finder - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lighting finder for a camera.

[0002]

2. Description of the Related Art FIG. 6A is a sectional view showing a conventional daylighting finder. The first optical system 101 for checking a subject image includes an objective lens 102, a half mirror 103, and an eyepiece 104. Second optical system 1 for superimposing a light beam transmitted through a field frame plate on the subject image
Reference numeral 05 denotes a lighting window 106, a total reflection mirror 107, a field frame plate 108, and an auxiliary lens 109.

FIG. 6 (b) is a view of only the field frame plate 108 of the daylighting finder as viewed from the front. Field frame plate 10
Reference numeral 8 denotes a glass obtained by subjecting aluminum to vapor deposition or the like. Only the autofocus (hereinafter referred to as AF) mark 108a and the field frames of the four frame marks 108b to 108e are transparent. Shaded).

Next, the mechanism of the daylighting finder will be briefly described. The first optical system 101 includes the objective lens 1
At 02, a scene such as a subject is captured, and the light flux passes through the half mirror 103 and is condensed by the objective lens 102. On the other hand, the second optical system 105 collects external light from the lighting window 106, and the light flux transmitted through the field frame (mark) of the field frame plate 108 is reflected by the total reflection mirror 107 and condenses into the auxiliary lens 109. The condensed light flux is reflected by the half mirror 103, further condensed by the objective lens 102, and superimposed on the subject image passing through the first optical system 101.

[0005]

In such a daylighting finder, a light beam transmitted through the field frame plate 108 is uniformly condensed by the auxiliary lens 109 like an optical path 100.
The image is superimposed on the subject image of the first optical system. On the other hand, the shape of the field frame plate is such that the aperture shape is rectangular (36 mm x
24 mm), the distance Le1 of the field frame plate 108 is always
11 (corresponding to 36 mm) is longer than the distance Le112 (corresponding to 24 mm), making it difficult to reduce the size of the second optical system.

Accordingly, an object of the present invention is to reduce the size of the field frame plate and, consequently, the size of the finder.

[0007]

According to the first aspect of the present invention, one surface of the auxiliary lens has a plane (9b) inclined with respect to the optical axis, and the other surface has a field frame. It is characterized by having a spherical surface (9d) for condensing a light beam transmitted through a field frame (mark) of the plate. According to a second aspect of the present invention, one surface of the auxiliary lens has a convex shape having a plane (9a) perpendicular to the optical axis and two planes (9b, 9c) inclined with respect to the optical axis. It is characterized by having.

According to a third aspect of the present invention, one surface of the auxiliary lens is convex having a plane (29a) perpendicular to the optical axis and four planes (29b to 29e) inclined with respect to the optical axis. It is characterized by having a shape.

[0009]

In the daylighting finder according to the present invention, a light beam passing through a plane inclined with respect to the optical axis is refracted by the prism effect using the auxiliary lens, and can be superimposed on the subject image of the first optical system.

[0010]

FIG. 1 (a) is a horizontal sectional view of a daylighting finder according to a first embodiment of the present invention, and FIG. 1 (b) is a front view of only the field frame plate of the daylighting finder. is there.
The first optical system 1 for checking a subject image includes an objective lens 2, a half mirror 3, and an eyepiece 4.

A second optical system 5 for superimposing an AF mark or the like on a subject image of the first optical system 1 includes a lighting window 6, a total reflection mirror 7, a field frame plate 8, and an auxiliary lens 9.
An AF mark 8a serving as an AF target is provided at the center of the field frame plate 8, and frame marks 8b to 8e indicating the shooting range are provided at four corners. The AF mark 8a shown in FIG. 1B has the same size as the AF mark 108a shown in FIG.
b to 8e are also the frame marks 108b to 108b shown in FIG.
8e.

AF mark 8a and frame marks 8b-8
Since the size of e itself is the same as that of the related art, the amount of light entering from the lighting window 6 is the same even when the object scene is dark, and the frame mark and the like can be clearly observed. The field frame plate 8
Does not need to be glass, and may be constituted by a transmissive LCD or the like.

In this embodiment, the lighting window 6 is provided in the front direction. However, the lighting window 6 may be provided in the upper surface direction for lighting. Further, the field frame plate 8 may be illuminated by using an LED or EC (electroluminescence) instead of the lighting window 6. Next, the auxiliary lens 9 will be described with reference to FIG. The surface 9d of the auxiliary lens 9 on the half mirror 3 side is a spherical surface, and the opposite surface has a plane 9b perpendicular to the optical axis and planes 9b and 9c inclined with respect to the optical axis. It has a convex shape. Since the planes 9b and 9c have an inclination with respect to the optical axis, the optical path can be refracted similarly to the effect of the prism.

Next, the light beam 10 of the first embodiment will be described.
The field frame plate 8 has an AF mark 8a as shown in FIG.
, An area 82 including the frame marks 8b and 8c, and an area 83 including the frame marks 8d and 8e. The light beam that has passed through the AF mark 8a in the area 81 is reflected by the total reflection mirror 7, passes through the plane 9a of the auxiliary lens 9, is collected by the spherical surface 9d, and is superimposed on the first optical system.

The light beam having passed through the frame marks 8b and 8c in the area 82 is reflected by the total reflection mirror 7 and is reflected by the auxiliary lens 9
Is refracted by the effect of the prism on the flat surface 9b (without being condensed), is further condensed on the spherical surface 9d, and is superimposed on the first optical system. Area 83 frame mark 8
The light flux passing through d and 8e is reflected by the total reflection mirror 7, refracted by the effect of the prism on the plane 9c of the auxiliary lens 9, further condensed by the spherical surface 9d, and superimposed on the first optical system.

In this way, the light beam that has passed through the areas 82 and 83 is greatly bent unlike the light beam that has passed through the area 81 and is superimposed on the first optical system.
The distance Le1 of the field frame plate 8 can be shorter than the distance Le111 of the conventional field frame plate 108. In the first embodiment,
The distance Le2 of the field frame plate 8 and the distance Le112 of the conventional field frame plate 108 are the same length.

Therefore, when the photographer looks through the eyepiece 4, even if the field frame plate 8 is smaller than the conventional field frame plate 108, the AF marks 8a, 8a, The frame marks 8b to 8e can be observed. If the AF mark 8a is unnecessary, the auxiliary lens 9
The opposite side of the half mirror 3 is provided with the flat surface 9a without the flat surface 9a.
The two surfaces b and 9c may be formed in a convex shape.

Next, a second embodiment of the present invention will be described.
In the first embodiment, the distance Le111 of the field frame plate 108 (corresponding to the aperture of 36 mm) is reduced, but the distance Le112 is reduced.
(Corresponding to an aperture of 24 mm) may be reduced. In this case, it is possible to change the direction of the slope of the auxiliary lens 9. The auxiliary lens 9 of the second embodiment is obtained by rotating the lens shown in FIG. 2 by π / 2. FIG. 3 shows the field frame plate 18 in this case.

The distance Le11 of the field frame plate 18 is the same as the distance Le111 of the field frame plate 108, but the distance Le12 of the field frame plate 18 is equal to the distance Le11 of the field frame plate 108.
It is shorter than 1. Further, as a third embodiment of the present invention, an example is shown in which four frame marks are centered around the AF mark.

FIG. 4 shows the auxiliary lens 29 of the third embodiment, and FIG. 5 shows the field frame plate 8 using the auxiliary lens 29. Surface 2 of auxiliary lens 29 on half mirror 3 side
9f is a spherical surface, and the opposite surface is a plane 2 perpendicular to the optical axis.
9a, and planes 29b to 29e having a certain angle in four directions with respect to the plane 29a.

The AF mark 28a shown in FIG. 5 has the same size as the AF mark 108a shown in FIG. 6, and the frame marks 28b to 28e shown in FIG. 5 also have the same size as the frame marks 108b to 108e shown in FIG. It is. Next, the light beam of the third embodiment will be described. The light beam that has passed through the AF mark 28a is reflected by the total reflection mirror 7, passes through the plane 29a of the auxiliary lens 29, is collected by the spherical surface 29f, and is superimposed on the first optical system 1.

The light beam that has passed through the frame mark 28b is
The light beam reflected by the total reflection mirror 7, refracted by the plane 29b of the auxiliary lens 29 with the effect of a prism, further condensed by the spherical surface 29f, superimposed on the first optical system, and passed through the frame mark 28c is reflected by the total reflection mirror. The light is reflected at 7, is refracted by the effect of the prism on the plane 29c of the auxiliary lens 29, is further condensed on the spherical surface 29f, and is superimposed on the first optical system.

The light beam that has passed through the frame mark 29d is reflected by the total reflection mirror 7 and is reflected on the plane 2 of the auxiliary lens 29.
9d, refracted by the effect of a prism, and a spherical surface 29f
Is reflected by the first optical system, passes through the frame mark 28e, is reflected by the total reflection mirror 7, is refracted by the prism effect on the flat surface 29e of the auxiliary lens 29, and is further condensed by the spherical surface 29f. And superimposed on the first optical system.

The distance Le21 of the field frame plate 28 is shorter than the distance Le111 of the field frame plate 108,
8 is also the distance Le111 of the field frame plate 108.
It is shorter than. The effect of reducing the vertical and horizontal distances of the field frame plate can be achieved even if the auxiliary lens is spherical on both surfaces (or has a large refractive index). However, AF marks and frame marks 28b to 28e provided on the field frame plate are provided. The size of itself must be reduced. AF mark,
As the size of the frame mark itself decreases, the amount of light passing through the field frame plate decreases.

Therefore, for example, when the object scene is dark, the amount of light taken in from the lighting window 6 becomes small, and the photographer may not be able to observe the AF mark and the frame mark clearly. However, in the third embodiment of the present invention, since the sizes of the AF marks and the frame marks 28b to 28e themselves remain the same, the frame marks can be clearly observed even when the amount of light taken in from the lighting window 6 is small.

[0026]

According to the present invention, there is provided a daylighting finder having a spherical surface for condensing a light beam transmitted through the field frame plate, and the other surface having two or more flat surfaces. In the daylighting finder of the present invention, since one surface of the auxiliary lens has a plane inclined with respect to the optical axis, it is possible to refract a light beam passing through the plane having the inclination. Since the light beam obtained can be superimposed on the first optical system, the size of the field frame plate can be reduced.

Further, since the size of the field frame plate is reduced, the size of the total reflection mirror and the like can be reduced, so that the size of the daylighting finder can be reduced. In addition, since the plane inclined with respect to the optical axis only refracts the light beam uniformly and does not condense it, even when the amount of light illuminated by the lighting unit is small, the amount of light passing through the field frame plate is constant. .

[Brief description of the drawings]

FIG. 1 is a sectional view of a daylighting finder according to a first embodiment and a front view of a field frame plate.

FIG. 2 is a diagram of an auxiliary lens according to a first example.

FIG. 3 is a view frame plate of a second embodiment.

FIG. 4 is a diagram of an auxiliary lens according to a third embodiment.

FIG. 5 is a view frame plate of a third embodiment.

FIG. 6 is a sectional view of a conventional daylighting finder and a front view of a field frame plate.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 First optical system 2 Objective lens 3 Half mirror 4 Eyepiece 5 Second optical system 6 Lighting window 7 Total reflection mirror 8 Field frame plate of the first embodiment 8a AF mark 8b-8e Frame mark 9 Auxiliary of the first embodiment Lens 18 Field frame plate of the second embodiment 28 Field frame plate of the third embodiment 29 Auxiliary lens of the third embodiment 108 Conventional field frame plate 109 Conventional auxiliary lens

Claims (3)

(57) [Claims] 1. A first optical system, comprising an objective lens, means having semi-transmission characteristics, and an eyepiece, for confirming an object image, a field frame plate for transmitting a part of a light beam, and a field frame of the field frame plate. In a daylighting finder having an auxiliary lens for condensing the passed light beam and having a second optical system for superimposing the collected light beam on the subject image, one surface of the auxiliary lens is positioned with respect to an optical axis. A plane having an inclined surface, and a transmitted light beam at a position corresponding to the flat surface is refracted by the prism effect, and the other surface is a spherical surface that condenses the light beam passed through the field frame. Daylighting finder characterized by: 2. The daylighting finder according to claim 1, wherein one surface of the auxiliary lens has a convex shape having a plane perpendicular to an optical axis and two planes inclined with respect to the optical axis. And
A daylighting finder, wherein a transmitted light beam at a position corresponding to the two planes is refracted by a prism effect. 3. The daylighting viewfinder according to claim 1, wherein one surface of the auxiliary lens has a convex shape having a plane perpendicular to an optical axis and four planes inclined with respect to the optical axis. And
A daylighting finder characterized by refracting a transmitted light beam at positions corresponding to the four planes with a prism effect.