Optics: image projectors – Reflector – Plural
Patent
1986-06-10
1988-08-23
Haroian, Harry N.
Optics: image projectors
Reflector
Plural
353 78, G02B 1700
Patent
active
047657332
DESCRIPTION:
BRIEF SUMMARY
TECHNICAL FIELD
The present invention relates to a light projector which can be used as a slide projector, an overhead projector, a motion picture projector or the like.
BACKGROUND ART
In the conventional slide projectors, motion picture projectors and the like, a lens or lenses are inserted in the path of light rays projected from a light source so that in order to sharply focus an image on a screen, the positions of an original and the lens or lenses must be adjusted. In other words, a projected image cannot be sharply focused on a screen regardless of the relative position of the original with respect to the lens or lenses. Furthermore, the lens is accompanied by a problem in that the quantity of light which passes therethrough is insufficient in the peripheral portion thereof so that the peripheral portion of the image focused on the screen becomes somewhat darker. In addition, the problems such as color dispersion, chromatic aberration, curvature of field and the like of lenses cannot be completely eliminated. Moreover, with image projectors utilizing the lenses, the position of a projector relative to a projection screen is limited.
The present invention was made in view of the above and has for its object to provide a light projector which can not only overcome the above described problems but also attain excellent features to be described below.
DISCLOSURE OF THE INVENTION
According to the present invention, a light projector comprises a point light source and light reflecting means disposed at a position to reflect light rays emitted from the point light source. The light reflecting means comprises means for controlling the distribution of the reflected light rays, and light ray shaping means for determining the direction of the reflected light rays in such a way that the reflected light rays are focused substantially at a single point.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a vertical sectional view of a first preferred embodiment of a light projector in accordance with the present invention;
FIG. 2 is a perspective view thereof;
FIG. 3 is a schematic view explanatory of the optical system of the light projector as shown in FIG. 1;
FIG. 4 is a schematic view explanatory of the effects of the present invention;
FIGS. 5 through 14 are schematic views showing, respectively, the optical principles of various modifications of the first embodiment shown in FIG. 1;
FIG. 15 is a vertical sectional view of a second preferred embodiment of the present invention in which a lens is inserted in an optical system; and
FIGS. 16 and 17 are views showing the optical principles of modifications, respectively, of the second embodiment shown in FIG. 15 in which a lens is inserted into an optical system.
BEST MODES FOR CARRYING OUT THE INVENTION
FIGS. 1 and 2 show a light projector to which the principle of the present invention is applied. In FIGS. 1 and 2, reference numeral 1 designates a case in which a light source L is fixedly positioned. The light source L is of such a size that it may be considered to be substantially a point light source. In this case, even when a light source has a relatively large volume, a light point at which light rays emitted from the light source are converged through a lens may be considered as a point light source. In the case of the first preferred embodiment shown in FIG. 1, the light source L is located on an imaginary axis O--O (to be referred to as "the axis" hereinafter) which extends in the horizontal direction.
Within the case 1, a first reflecting mirror M.sub.1 is supported fixedly by supporting members 2 and 3 in such a way that the reflecting surface of the reflecting mirror M.sub.1 is directed downwardly. The first reflecting mirror M.sub.1 is disposed above the light source L. A second reflecting mirror M.sub.2 which is spaced apart from the first reflecting mirror M.sub.1 in the horizontal direction is disposed fixedly on the bottom wall of the case 1 and supported by supporting members 4 and 5 in such a way that the reflecting surface of the second r
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