JPH05313228A - Lighting type finder - Google Patents

Abstract

PURPOSE:To make the size of a visual field frame plate and a finder small by constituting one face of an auxiliary lens as a plane inclined to an optical axis, and the other face as a spherical face converging a luminous flux finished to transmit a visual frame. CONSTITUTION:This lighting type finder is provided with a first optical lens system 1 composed of an objective lens 2, a half mirror 3, and an eyepiece 4, and confirming a subject, and a second optical system 5 composed of the visual field frame plate 8 transmitting a part of the luminous flux as illumination from a lighting means, a total reflection mirror 7 reflecting the luminous flux finished to transmit the visual frame plate 8, and the auxiliary lens 9 converging the reflected luminous flux and superimposing the luminous fluxes converged on the subject. In this finder, one face of the auxiliary lens 9 is the plane 9b inclined to the optical axis, to refract the transmitted luminous flux at a position corresponding to the plane 9b, by a prism effect, and the other face is the spherical face 9d converging the luminous flux transmitted through the visual frame plate 8.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a daylighting 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 confirming a subject image is composed of an objective lens 102, a half mirror 103, and an eyepiece lens 104. Second optical system 1 for superimposing the light flux transmitted through the field frame plate on the subject image
Reference numeral 05 includes a daylighting window 106, a total reflection mirror 107, a field frame plate 108, and an auxiliary lens 109.

FIG. 6B is a front view of only the field frame plate 108 of the daylighting finder. Field frame plate 10
Reference numeral 8 denotes glass that is subjected to aluminum vapor deposition or the like, and only the autofocus (hereinafter referred to as AF) mark 108a and the field frames of the four frame marks 108b to 108e are transparent, and portions other than these marks are masks ( It is shielded from light.

Next, the mechanism of the daylighting finder will be briefly described. The first optical system 101 includes the objective lens 1
At 02, a landscape such as a subject is captured, and the light flux thereof 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 daylighting 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 enters the auxiliary lens 109 and is condensed. The condensed light flux is reflected by the half mirror 103, further condensed by the objective lens 102, and superimposed on the subject image which has passed through the first optical system 101.

[0005]

In such a daylighting finder, the light flux transmitted through the field frame plate 108 is uniformly condensed by the auxiliary lens 109 like the optical path 100,
It is superimposed on the subject image of the first optical system. On the other hand, regarding the shape of the field frame plate, the shape of the aperture is rectangular (36 mm ×
24 mm), so 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), and it is difficult to downsize the second optical system.

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

[0007]

According to a first aspect of the present invention, one surface of the auxiliary lens has a flat surface (9b) inclined with respect to the optical axis, and the other surface of the auxiliary lens has a field frame. It is characterized in that it has a spherical surface (9d) for condensing the light flux that has passed through the visual 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

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

[0009]

In the daylighting finder of the present invention, an auxiliary lens can be used to refract a light flux passing through a plane having an inclination with respect to the optical axis by the prism effect and superimpose it on the subject image of the first optical system.

[0010]

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 a field frame plate of the daylighting finder. is there.
The first optical system 1 for confirming a subject image is composed of an objective lens 2, a half mirror 3 and an eyepiece lens 4.

The second optical system 5 for superimposing an AF mark or the like on the subject image of the first optical system 1 is composed of a daylighting window 6, a total reflection mirror 7, a field frame plate 8 and an auxiliary lens 9.
The field frame plate 8 is provided with an AF mark 8a, which is an AF target, at the center, and frame marks 8b to 8e indicating the photographing 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. 6, and the frame mark 8 shown in FIG.
b-8e are also the frame marks 108b-10 shown in FIG.
It has the same size as 8e.

The AF mark 8a and the frame marks 8b-8
Since the size of e itself is the same as the conventional one, the amount of light entering from the daylighting window 6 is the same even when the field is dark, and the frame mark and the like can be clearly observed. The field frame plate 8
Need not be glass, but may be a transmissive LCD or the like.

Further, although the lighting window 6 is provided in the front direction in this embodiment, the lighting window 6 may be provided in the upper direction for lighting. Further, instead of the lighting window 6, an LED or EC (electro luminescence) may be used to illuminate the field frame plate 8. Next, the auxiliary lens 9 will be described with reference to FIG. A surface 9d of the auxiliary lens 9 on the half mirror 3 side is a spherical surface, and on the opposite surface thereof, a plane 9b perpendicular to the optical axis and planes 9b and 9c inclined with respect to the optical axis are provided. 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 luminous flux 10 of the first embodiment will be described.
The field frame plate 8 has an AF mark 8a as shown in FIG.
Is divided into an area 81 including the frame marks 8b and 8c and an area 83 including the frame marks 8d and 8e. The light flux that has passed through the AF mark 8a in the area 81 is reflected by the total reflection mirror 7, passes through the flat surface 9a of the auxiliary lens 9 and is converged by the spherical surface 9d to be superposed on the first optical system.

The light flux that has passed through the frame marks 8b and 8c in the area 82 is reflected by the total reflection mirror 7 and then the auxiliary lens 9
The light is refracted by the prism effect on the flat surface 9b (without being condensed), is further condensed by the spherical surface 9d, and is superposed on the first optical system. Frame mark 8 in area 83
The light fluxes passing through d and 8e are reflected by the total reflection mirror 7, refracted by the flat surface 9c of the auxiliary lens 9 with the effect of a prism, further condensed by the spherical surface 9d, and superposed on the first optical system.

In this way, the light flux passing through the areas 82 and 83 is greatly bent and superposed on the first optical system, unlike the light flux passing through the area 81.
The distance Le1 of the field frame plate 8 may be shorter than the distance Le111 of the field frame plate 108 of the conventional example. In the first embodiment,
The distance Le2 of the field frame plate 8 and the distance Le112 of the field frame plate 108 of the conventional example have the same length.

Therefore, when the photographer looks through the eyepiece lens 4, even if the field frame plate 8 is smaller than the conventional field frame plate 108, the AF mark 8a, The frame marks 8b to 8e can be observed. When the AF mark 8a is unnecessary, the auxiliary lens 9
On the opposite side of the half mirror 3 of FIG.
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 (corresponding to the aperture 36 mm) of the field frame plate 108 is shortened.
(Corresponding to aperture 24mm) may be shortened. 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. The field frame plate 18 in this case is shown in FIG.

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 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 in which four frame marks are centered on the AF mark will be described.

FIG. 4 shows the auxiliary lens 29 of the third embodiment, and FIG. 5 shows the field frame plate 8 when the auxiliary lens 29 is used. Surface 2 of the auxiliary lens 29 on the 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 constant 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. Is. Next, the luminous flux of the third embodiment will be described. The light flux passing through the AF mark 28a is reflected by the total reflection mirror 7, passes through the flat surface 29a of the auxiliary lens 29, is condensed by the spherical surface 29f, and is superposed on the first optical system 1.

The light flux passing through the frame mark 28b is
The light flux reflected by the total reflection mirror 7, refracted by the flat surface 29b of the auxiliary lens 29 with the effect of a prism, condensed by the spherical surface 29f, superposed on the first optical system, and passed through the frame mark 28c is a total reflection mirror. The light is reflected by 7 and is refracted by the flat surface 29c of the auxiliary lens 29 with the effect of a prism, and is further condensed by the spherical surface 29f to be superposed on the first optical system.

The light flux that has passed through the frame mark 29d is reflected by the total reflection mirror 7 and is reflected by the plane 2 of the auxiliary lens 29.
It is refracted by the effect of a prism at 9d, and spherical surface 29f.
The light flux that has been condensed by the first optical system, passed through the frame mark 28e, is reflected by the total reflection mirror 7, is refracted by the flat surface 29e of the auxiliary lens 29 with a prism effect, and is further condensed by the spherical surface 29f. And is 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, and the field frame plate 1
The distance Le22 of 8 is also the distance Le111 of the field frame plate 108.
It is shorter than The effect of shortening the vertical and horizontal distances of the field frame plate can be achieved even if both surfaces of the auxiliary lens are spherical (or when the refractive index is large), but AF marks and frame marks 28b to 28e provided on the field frame plate The size of itself must also be reduced. AF mark,
As the size of the frame mark itself becomes smaller, the amount of light passing through the field frame plate becomes smaller.

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

[0026]

EFFECT OF THE INVENTION 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 flat surface inclined with respect to the optical axis, it is possible to refract a light beam passing through the flat surface having such an inclination. Since the formed light flux can be superposed on the first optical system, the field frame plate can be made small.

Further, since the total size of the total reflection mirror and the like can be reduced by reducing the size of the field frame plate, it is possible to reduce the size of the daylighting finder. Further, since the plane inclined with respect to the optical axis only refracts the light flux and does not condense it, the amount of light passing through the field frame plate is constant even when the amount of light illuminated by the daylighting means is small. ..

[Brief description of drawings]

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

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

FIG. 3 is a view frame plate according to a second embodiment.

FIG. 4 is a diagram of an auxiliary lens of a third example.

FIG. 5 is a field frame plate according to a third embodiment.

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

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 1st optical system 2 Objective lens 3 Half mirror 4 Eyepiece 5 5 2nd optical system 6 Illumination window 7 Total reflection mirror 8 Field frame plate 8a of 1st Example 8a AF mark 8b-8e Framemark 9 Auxiliary of 1st Example Lens 18 Field-of-view frame plate of second example 28 Field-of-view frame plate of third example 29 Auxiliary lens of third example 108 Conventional field-of-view frame plate 109 Conventional auxiliary lens

Claims (3)

[Claims] 1. A first optical system comprising an objective lens, a half mirror and an eyepiece lens for confirming a subject image, a field frame plate for transmitting a part of a light beam illuminated by a daylighting means, and a field of view of the field frame plate. A daylighting finder having a second optical system including a mirror for reflecting the light flux transmitted through the frame and an auxiliary lens for condensing the reflected light flux, wherein the second optical system superimposes the condensed light flux on the subject image. One surface of the lens has a plane having an inclination with respect to the optical axis, and the transmitted light flux at a position corresponding to the plane is refracted by the prism effect, and the other surface passes through the field frame. A daylighting finder that has a spherical surface that collects light flux. 2. The daylighting finder according to claim 1, wherein one surface of the auxiliary lens has a plane perpendicular to the optical axis and two planes inclined with respect to the optical axis to form a convex shape. Then
A daylighting finder that refracts a light flux transmitted at a position corresponding to the two planes with a prism effect. 3. The daylighting finder according to claim 1, wherein one surface of the auxiliary lens has a plane perpendicular to the optical axis and four planes inclined with respect to the optical axis to form a convex shape. Then
A daylighting finder that refracts a light flux transmitted through positions corresponding to the four planes by a prism effect.