JPS636860B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an in-finder display device, and more particularly to an in-finder display device that improves the visibility of the display in the viewfinder visual field due to changes in the brightness of external light.

Conventionally, various types of information are displayed within the field of view of the viewfinder, such as shooting range display, autofocus distance measurement range display, aperture value display, and shutter speed display. In order to display the information clearly and superimposed on the information, it is necessary to increase the brightness of the information display as the brightness of the outside scene increases.

In order to meet this need, conventional proposals have been made such as changing the brightness of the light source for information display, but the technical contents of this proposal are that the brightness of the light source changes little with respect to the external light flux, and that the brightness of the light source changes to the external light flux. On the other hand, there are drawbacks such as low brightness of the light source and the need for a large-capacity power source to power the light source.

Therefore, the present invention ameliorates these drawbacks and
To provide a display device in a viewfinder in which information display can be clearly recognized even under a bright outside scene.

Hereinafter, the present invention will be explained in detail based on the accompanying drawings.

Figure 1 shows the field of view inside the viewfinder.
Alternatively, information such as the autofocus distance measurement range 3 is displayed superimposed on the external light flux.

FIG. 2 is a block diagram showing an embodiment of the viewfinder display device of the present invention, in which the outside scene light flux passing through the zoom lens 20 is divided into two by a half mirror prism 21 into a finder light flux and a photographing light flux.
This photographing light beam is further focused on a film surface 24 via an aperture 22 and a master lens 23. On the other hand, the optical path of the finder light flux is directed toward the eyepiece by a half mirror 29 via a light control element 25 whose transmittance changes depending on the intensity of the light flux passing through it, and an objective lens 26.

This half mirror 29 has a light source 27 with a constant amount of light.
A light beam from a mask 28 on which a field frame or an autofocus distance measurement range frame illuminated by the above is printed is incident, and is combined with the finder light beam.

This combined light beam is observed by a photographer through an erecting lens 30 and an eyepiece 31, as shown in FIG. 1, for example.

With this configuration, when the brightness of the outside scene changes, the transmittance of the light control element 25 changes accordingly, so that the brightness of the visual field 1 is maintained appropriately even for extremely bright outside scenes, while the information display Since the brightness of 2 or 3 is constant, this information display remains easy to see.

Here, since the light control element 25 is inserted at a position completely unrelated to the photographing optical system, it goes without saying that there is no risk of adversely affecting the photographic screen.

FIG. 3 shows an embodiment in which the present invention is applied to a daylight type bright frame finder.

The external light flux passes through an objective lens 40 and a light control element 41 whose transmittance changes depending on the intensity of the passing light flux, and a field frame 44 illuminated with external light by a half mirror 42 and a total reflection mirror 45. The images are combined and observed by the photographer through the eyepiece lens 43.

In this type of finder, the field frame 44 is often illuminated by external light, but the effect of the light control element 41 is exactly the same as in the embodiment shown in FIG.

As described above, it goes without saying that the present invention can be applied to various other types of finders.

As explained above, according to the device of the present invention, the information displayed in the viewfinder can be maintained clearly regardless of the brightness of the outside scene without requiring any moving parts by inserting only one light control element. . In particular, it is possible to provide an in-viewer display device that is extremely superior not only in terms of cost but also in terms of performance, compared to the conventional method of changing the amount of light from a light source.

[Brief explanation of the drawing]

FIG. 1 shows a field of view within the viewfinder, FIG. 2 is a block diagram showing one embodiment of the present invention, and FIG. 3 is a block diagram showing another embodiment of the present invention. 1...Finder field of view, 1, 2...Photographing field of view frame, 3
...Autofocus distance measuring field frame, 20...Zoom lens, 23...Master lens, 24...Film surface,
25... Light control element, 26... Objective lens, 27... Light source, 28... Mask, 29... Half mirror, 30...
Erecting lens, 31... Eyepiece lens, 40... Objective lens, 41... Light control element, 42... Half mirror, 43
...eyepiece, 44...mask, 45...total reflection mirror.

Claims (1)

[Scope of Claims] 1. In a viewfinder display device in which information such as a viewing range, an autofocus distance measurement range, or exposure information is displayed within the viewfinder field of view by using a half mirror or the like and superimposed on an external light flux. 2. An in-finder display device, characterized in that a dimming element whose transmittance changes depending on the intensity of light is disposed outside the information display optical path and within the finder optical path. 2. The in-finder display device according to claim 1, wherein the information display is performed by a beam of light transmitted through a mask that is irradiated with a lamp of a constant light amount.