Photography – With exposure objective focusing means – focusing aid – or... – Having indicator
Reexamination Certificate
1999-12-22
2001-09-18
Perkey, W. B. (Department: 2851)
Photography
With exposure objective focusing means, focusing aid, or...
Having indicator
C396S296000
Reexamination Certificate
active
06292629
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an indicator provided within a view finder for a single lens reflex camera, and more precisely, relates to an indicator in which photographing information to be indicated is superimposed on an object image.
2. Description of the Related Art
A superimposing indicator within a finder is known in the art, in which a focusing plate is provided with, for example, deflector elements (reflecting elements) which are illuminated by LEDs. In this type of indicator within a finder, if the number of the deflector elements provided on the focusing plate is increased, it is difficult not only to arrange a number of LEDs in a narrow area at the edge of the focusing plate, but also to precisely make light incident upon a desired deflector element to be illuminated, so as not to undesirably illuminate the surrounding deflector elements which are not intended to be illuminated.
Moreover, there is also known an indicator within a finder in which a focusing plate is a liquid crystal plate, so that photographing information is indicated through the liquid crystal plate. In this type of indicator, however, the indication of the finder is so dark that it is difficult for a viewer to correctly recognize the indication thereof.
In another known indicator in which a half mirror is provided between an eyepiece and a pentagonal prism or a pentagonal mirror of a finder optical system, light emitted from LEDs is split, and is made incident upon the finder optical system through the half mirror. However, there are problems with the fundamental functions of the finder, i.e., the magnification of the finder is decreased, or the eye relief is increased, etc.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide an indicator within a finder for a single lens reflex camera, in which various information is indicated in the finder field-of-view, wherein the information can be clearly and correctly indicated and a viewer (i.e., a user) can easily recognize the indication thereof, without sacrificing the fundamental functions of the finder.
In order to achieve the above mentioned object, there is provided an indicator provided within a view finder for a single lens reflex camera, including a pentagonal prism having a roof reflection surface, the roof reflection surface having two reflection surfaces normal to each other, wherein the roof reflection surface reflects light emitted from a focusing plate which is located at a position optically equivalent to an imaging plane of a photographic lens of the single lens reflex camera, and a third reflection surface which reflects the light reflected by the roof reflection surface toward an eyepiece, wherein the third reflection surface includes a semitransparent surface. The indicator includes an auxiliary prism adhered to the semitransparent surface; an indicator plate including an information mask which lies in a plane substantially perpendicular to the optical axis of the eyepiece; and an illumination light source which emits light through the information mask of the indicator plate, in that order from the opposite side of the auxiliary prism with respect to the third reflection surface thereof; and a diopter correcting lens, which makes the position of the indicator plate optically equivalent to the position of the focusing plate, provided between the auxiliary prism and the indicator plate.
According to another aspect of the present invention, there is provided an indicator provided within a view finder for a single lens reflex camera, including a pentagonal mirror having a roof reflection surface, the roof reflection surface having two reflection surfaces normal to each other, wherein the roof reflection surface reflects light emitted from a focusing plate which is located at a position optically equivalent to an imaging plane of a photographic lens of the single lens reflex camera, and a third reflection surface which reflects the light reflected by the roof reflection surface toward an eyepiece, wherein the third reflection surface includes a semitransparent surface. The indicator includes an indicator plate including an information mask to be indicated within the finder field-of-view and which lies in a plane substantially perpendicular to the optical axis of the eyepiece, and an illumination light source which emits light through the information mask of the indicator plate, in that order from the third reflection surface; and a diopter correcting lens, which makes the position of the indicator plate optically equivalent to the position of the focusing plate, provided between the third reflection surface and the indicator plate.
In regard to the two above described aspects of the present invention, it is preferable that the indicator includes a plurality of the information masks, wherein the illumination light source can selectively emit light so as to correspond to the information masks. Preferably, the information masks define object distance measuring area masks. Preferably, the semitransparent surface of the third reflection surface has a transmittance which permits 5 to 20% of visible light emitted from the illumination light source to pass therethrough.
According to another aspect of the present invention, there is provided an indicator provided within a view finder for a single lens reflex camera, including a pentagonal prism having a roof reflection surface, the roof reflection surface having two reflection surfaces normal to each other, wherein the roof reflection surface reflects light emitted from a focusing plate which is located at a position optically equivalent to an imaging plane of a photographic lens of the single lens reflex camera, and a third reflection surface which reflects the light reflected by the roof reflection surface toward an eyepiece, wherein the third reflection surface includes a semitransparent surface. The indicator includes an auxiliary prism adhered to the semitransparent surface; an LCD panel in which information to be indicated within the finder field-of-view is indicated; a projection lens; and an illumination light source which emits light to illuminate the LCD panel through the projection lens, in that order from the opposite side of the auxiliary prism with respect to the third reflection surface thereof; and a diopter correcting lens, which makes the position of the LCD panel optically equivalent to the position of the focusing plate, provided between the third reflection surface and the LCD panel.
According to another aspect of the present invention, there is provided an indicator provided within a view finder for a single lens reflex camera, including a pentagonal mirror having a roof reflection surface, the roof reflection surface having two reflection surfaces normal to each other, wherein the roof reflection surface reflects light emitted from a focusing plate which is located at a position optically equivalent to an imaging plane of a photographic lens of the single lens reflex camera, and a third reflection surface which reflects the light reflected by the roof reflection surface toward an eyepiece, wherein the third reflection surface defines a semitransparent surface. The indicator includes an LCD panel in which information to be indicated within the finder field-of-view is indicated; a projection lens; and an illumination light source which emits light to illuminate the LCD panel through the projection lens, in that order from the third reflection surface; and a diopter correcting lens, which makes the position of the LCD panel optically equivalent to the position of the focusing plate, provided between the third reflection surface and the LCD panel.
In regard to the two above-described aspects, it is preferable that the projection lens includes a Fresnel lens. Preferably, the projection lens is provided with an aspherical surface. Preferably, the semitransparent surface of the third reflection surface has a transmittance which permits approximately 5% to 20% of visible light emitted from the illuminat
Asahi Kogaku Kogyo Kabushiki Kaisha
Greenblum & Bernstein P.L.C.
Perkey W. B.
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