Overhead projector
AssigneeFuji Photo Optical Co., Ltd.
InventorsShigeo Mizukawa, Masaaki Morizumi, Katsuo Katagiri
Life of this patent
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Abstract
An overhead projector for projecting an image of a sheet material placed on a flat stage onto a remote screen standing almost vertically has a projection optical system with its optical axis aligned with a normal line of the stage. The projection optical system is shifted keeping the optical axis in parallel with the normal line so as to project an image at an angle of elevation onto the screen.
Claims8
An overhead projector for projecting an image of sheet material on a remote screen standing almost vertically, said overhead projector comprising:
- a stage having a stage surface on which the sheet material is placed;
- a light source disposed below said stage for illuminating said sheet material;
- a projection lens system having an optical axis which is aligned with a normal line, normal to said stage surface, and projecting the image of said sheet material;
- a reflective projection mirror, disposed above said projection lens system at an angle of 45 degrees with respect to said optical axis of said projection lens system, for reflecting and directing said image horizontally toward said remote screen, said reflective projection mirror being rotatively shiftable so as to reflect said image at an angle of elevation;
- and
- linkage means for operationally linking at least said projection lens system and said reflective projection mirror to each other, rotatively shifting said reflective projection mirror, and shifting said projection lens system in position relative to said stage surface while keeping said optical axis parallel to said normal line when rotatively shifting said reflective projection mirror;
- wherein said linkage means is further for operationally coupling said stage to said projection lens system so as to rotatively shift it through an angle which is the same as an angle through which said projection lens system is rotatively shifted.
An overhead projector for projecting an image of sheet material on a remote screen standing almost vertically, said overhead projector comprising:
- a stationary stage having a flat horizontal stage surface on which the sheet material is placed;
- light source means for illuminating said sheet material;
- a projection optical system, disposed above said stage, for projecting and directing horizontally an image of said sheet material onto said remote screen;
- and
- linkage means, operationally linking said light source means and said projection optical system to each other, for causing an opposite horizontal shift in position relative to said stage between said projection optical system and said light source means so that said projection optical system projects said image at an angle of elevation;
- wherein said stationary stage is transparent, said light source means is disposed below said stationary stage, said linkage means includes a link lever pivoted to said stationary stage so as to rotate in a vertical plane and supporting said projection optical system and said light source means on opposite sides of said stationary stage, said linkage means further includes a first slider to which said projection optical system is secured and a second slider to which said light source means is secured, the first and second sliders being engaged with said link lever so as to be horizontally slid in opposite directions by said link lever, and said light source means comprises a stationary light source and a reflection mirror rotatably attached to said second slider, said reflection mirror being rotated through an angle of .theta./2 when an angle of elevation of .theta. is required.
An overhead projector for projecting an image of sheet material on a remote screen standing almost vertically, said overhead projector comprising:
- a stationary stage having a flat horizontal stage surface on which the sheet material is placed;
- light source means for illuminating said sheet material;
- a projection optical system, disposed above said stage, for projecting and directing horizontally an image of said sheet material onto said remote screen;
- and
- linkage means, operationally linking said light source means and said projection optical system to each other, for causing an opposite horizontal shift in position relative to said stage between said projection optical system and said light source means so that said projection optical system projects said image at an angle of elevation;
- wherein said stationary stage is reflective, said light source means is disposed above said stationary stage and said linkage means includes a link lever pivoted on a vertical axis above said stationary stage so as to rotate in a horizontal plane and supporting said projection optical system and said light source means on opposite sides of said vertical axis.
Dependencies are inferred from the claim text.