JPH10177209A - In-finder display device for single lens reflex camera - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make the display of photographic information brighter in a finder and also to make the display more easily to see. SOLUTION: An object image formed on a finder screen on the upper surface 11a of a reticle 11 through a photographic optical system 14 and a quick return mirror 13 is observed through an eyepiece 12. Fresnel lens formed on the rear surface 11b of the reticle 11 is provided with an action of coupling the exit pupil of the photographic optical system 14 and the observation side pupil position of the eyepiece 12. The photographic information projected by a photographic information projecting unit 30 is projected and displayed on a prescribed projection position of the finder screen. The photographic information projecting unit 30 is arranged on a line linking the exit pupil of the photographic optical system 14 with the projection position.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a display device in a finder for superimposing photographing information and the like on a subject image displayed in a finder of a single-lens reflex camera.

[0002]

2. Description of the Related Art A conventional display device in a viewfinder of a single-lens reflex camera is disclosed in, for example, Japanese Patent Application Laid-Open No. 6-324393. FIG. 1 shows an optical system of the conventional single-lens reflex camera, and FIG. 2 is a diagram showing the optical system shown in FIG. 1 developed so that the optical axis of the photographing optical system is aligned. As shown in these figures, in the display device in the viewfinder, a photographing report projection unit 50 is arranged near the tip of the quick return mirror 40 in an inclined state. The photographing information projecting unit 50 includes an information chart 52 provided above the light emitting diode 51 and a projection lens 53 provided above the information chart 52. Characters and the like corresponding to the photographing information are formed on the information chart 52. By causing the light emitting diode 51 to emit light, the characters and the like of the photographing information are formed on the focus plate 41 provided above the quick return mirror 40. You. This photographing information is observed together with the subject image by the eyepiece 42 of the finder.

[0003]

As described above, the conventional photographing information projection unit 50 is provided at a position facing the edge of the focus plate 41, and the projection optical path of the photographing information does not interfere with the quick return mirror 40. That is, the light flux K1 transmitted through the imaging optical system 43 and the light flux K2 emitted from the imaging information projection unit 50 enter the focusing plate 41 at mutually different incident angles. The focus plate 41 is provided with a Fresnel lens. Most of the light flux K1 from the photographing optical system 43 is guided to the eyepiece 42, while only a small part of the light guided from the photographing information projection unit 43 to the eyepiece 42. is there. For this reason, the display of the photographing information tends to be dark in the viewfinder, and depending on the position of the photographer's eye E with respect to the eyepiece 42, the display of the photographing information may not be visible.

[0004] It is an object of the present invention to make the display of photographing information in the viewfinder even brighter and easier to see.

[0005]

A display device in a finder of a single-lens reflex camera according to the present invention guides a light beam transmitted through a photographing optical system to a finder screen to thereby convert an object image formed on the finder screen into an eyepiece lens. In a single-lens reflex camera to observe with a condenser lens provided in the vicinity of the finder screen and having an action of making the exit pupil of the photographing optical system conjugate with the eyepiece-viewing-side pupil position, a predetermined projection area on the finder screen A photographing information projecting unit for projecting and displaying photographing information, wherein a projection optical path of the photographing information by the photographing information projecting unit connects an arbitrary point in an exit pupil of the photographing optical system and an arbitrary point in a projection area. The feature is that it almost matches the line.

A mirror is provided between the photographing optical system and the finder screen to guide the light transmitted through the photographing optical system to the finder screen. This mirror is, for example, a semi-transmissive mirror, and the photographing information projecting means projects the photographing information through this semi-transmissive mirror.

[0007] The photographing information projecting means includes, for example, a light emitter, an information chart illuminated by the light emitter, and a projection lens for forming an image of the information chart on a finder screen.

The condenser lens is formed, for example, as a Fresnel lens.

[0009]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 3 is a diagram showing an optical system of a single-lens reflex camera to which one embodiment of the present invention is applied. FIG.
FIG. 4 is an expanded view of the optical system shown in FIG. 3 so that the optical axis of the photographing optical system is aligned.

The focus plate 11 faces the lower surface of the pentaprism 20, that is, the entrance surface 21, and the eyepiece 12 of the finder has an exit surface 2 formed on the back surface of the pentaprism 20.
2. The quick return mirror 13 is provided below the focus plate 11, and the photographing optical system 14 is provided in front of the quick return mirror 13. The quick return mirror 13 is a semi-transmissive mirror. The quick return mirror 13 is supported by a support shaft 15 provided at a portion on the emission surface 22 side of the pentaprism 20, and has a tilted position shown in FIG. It is rotatable between.

The upper surface 11a of the focus plate 11, that is, the surface facing the entrance surface 21 of the pentaprism 20 is a diffusion surface, and the lower surface 11b of the focus plate 11 is formed with a Fresnel lens which is a condenser lens. This Fresnel lens has the function of making the exit pupil of the photographing optical system 14 conjugate with the viewing-side pupil position of the eyepiece 12.

When the quick return mirror 13 is in the inclined position and the aperture in the photographing optical system 14 is open, the light beam transmitted through the photographing optical system 14 is reflected by the quick return mirror 13 and the finder screen of the focus plate 11 That is, it is guided to the upper surface 11a, where the subject image is formed. This subject image is observed by the photographer's eyes E via the pentaprism 20 and the eyepiece 12. On the other hand, when the quick return mirror 13 is in the horizontal position, the light beam transmitted through the photographing optical system 14 is guided to the film surface (not shown) below the quick return mirror 13 according to opening and closing of a shutter (not shown), A subject image is recorded on the film surface.

Below the tip of the quick return mirror 13, a photographing information projection unit 30 is provided.
The photographing information projection unit 30 includes an LED 31 that is a luminous body.
And an information chart 32 illuminated by the LED 31
And a projection lens 33. Information chart 32 is L
The projection lens 33 is provided closer to the focus plate 11 than the ED 31, and the projection lens 33 is provided closer to the focus plate 11 than the information chart 32.

In the information chart 32, a character display corresponding to the photographing information is formed. FIG. 5 shows an example of the information chart 32. The information chart 32 has a character display 32 of "P" having low transmittance at the center of the peripheral portion 32a having high transmittance.
b is formed. Note that "P" in this character display indicates a panoramic shooting mode. The image of the information chart 32 is projected and displayed by the projection lens 33 on a predetermined projection area of the upper surface 11a (finder screen) of the focus plate 11, and this projection area is outside the area where the subject image is formed. FIG. 6 shows an example of the image of the information chart 32 formed on the focus plate 11, and the image 11c of the character display is formed outside the panorama size frame 11d.

In a state where the optical axis of the photographing optical system 14 is expanded as shown in FIG.
It is arranged on a straight line J connecting the center P1 of the exit pupil of the photographing optical system 14 and the geometric center Q of the projection area on the focus plate 11 (the geometric center of the image 11c in FIG. 6). The optical axis of the imaging information projection unit 30 substantially coincides with the straight line J. That is, the principal ray of the light beam emitted from the imaging optical system 14 substantially coincides with the straight line J, and the imaging information is transmitted through the quick return mirror 13 and projected onto the projection area on the focus plate 11.

FIG. 7 is a diagram showing characteristics of the quick return mirror 13 as a semi-transmissive mirror. The solid line A indicates the visibility, and the solid line B indicates the LED 3 of the photographing information projection unit 30.
1 shows a light intensity distribution, and the solid line C indicates 45 ° of the semi-transmissive mirror.
The transmittance is shown. As shown in this figure, the average value V1 of the 45 ° transmittance in the emission wavelength region of the LED 31 is higher than the average value V2 of the 45 ° transmittance in the visible region of the semi-transmissive mirror.

Therefore, the photographing information projected by the photographing information projecting unit 30 efficiently passes through the quick return mirror 13 and is projected on the focus plate 11, and is guided to the eyepiece lens 12 more efficiently, so that clear photographing information is obtained. To be observed.

As described above, according to the present embodiment, the light beam corresponding to the photographing information projected by the photographing information projecting unit 30 is efficiently guided to the eyepiece 12, and the display of the photographing information in the viewfinder is conventionally performed. Also become brighter and easier to see. Therefore, as compared with the prior art, L
The light amount of the ED 31 can be small, and the current consumption required for causing the LED 31 to emit light can be reduced.

In the above-described embodiment, the imaging information projecting unit 3 is set in a state where the optical axis of the imaging optical system 14 is expanded.
Although the optical axis of 0 and the principal ray almost coincided with each other, this optical axis does not necessarily have to coincide with the principal ray.
1 may be perpendicular. In this case, the information chart 32
Is moved in a direction parallel to the focus plate 11, for example, the image forming position of the image of the information chart 32 on the focus plate 11 can be adjusted.

[0020]

As described above, according to the present invention, the display of photographing information in the viewfinder is bright and easy to see.

[Brief description of the drawings]

FIG. 1 is a diagram showing an optical system of a conventional single-lens reflex camera.

FIG. 2 is a diagram showing the optical system shown in FIG. 1 developed so that the optical axis of the photographing optical system is aligned.

FIG. 3 is a diagram showing an optical system of a single-lens reflex camera to which one embodiment of the present invention is applied.

FIG. 4 is a diagram showing the optical system shown in FIG. 3 developed so that the optical axis of the photographing optical system is aligned.

FIG. 5 is a diagram showing an example of an information chart.

FIG. 6 is a diagram illustrating an example of a projection area where an image of an information chart is formed on a focus plate.

FIG. 7 is a diagram showing characteristics of a quick return mirror as a semi-transmissive mirror.

[Explanation of symbols]

 REFERENCE SIGNS LIST 11 focus plate 11 a finder screen 11 b Fresnel lens 12 eyepiece 13 quick return mirror 20 pentaprism 30 shooting information projection unit 31 LED 32 information chart 33 projection lens

Claims (5)

[Claims] 1. A single-lens reflex camera for observing a subject image formed on a finder screen with an eyepiece lens by guiding a light beam transmitted through an imaging optical system to a finder screen, wherein the single-lens reflex camera is provided near the finder screen, A condenser lens having an action of making the exit pupil of the photographing optical system conjugate with the eyepiece-side pupil position on the eyepiece side; and A projection optical path of the photographing information by the photographing information projecting means substantially coincides with a line connecting an arbitrary point in the exit pupil of the photographing optical system and an arbitrary point in the projection area; Display device in the viewfinder of a reflex camera. 2. The display device in a finder according to claim 1, wherein a mirror is provided between the photographing optical system and the finder screen. 3. The display device according to claim 2, wherein the mirror is a semi-transmissive mirror, and the photographing information projecting unit projects the photographing information through the semi-transmissive mirror. 4. The photographic information projection means comprises a light emitter, an information chart illuminated by the light emitter, and a projection lens for forming an image of the information chart on the finder screen. The display device in a finder according to claim 1. 5. The display device according to claim 1, wherein the condenser lens is formed as a Fresnel lens.