Patent ID: 6260974
Filing Date: 2001-07-17
Classification: G02B,H04N

Abstract:
An image projecting apparatus comprising:a light source;converging means for converging a light from said light source and forming a light source image;optical means having a first end surface, a second end surface and a reflecting surface for connecting the first and second end surfaces, and constructed such that the light from said light source is incident on the first end surface, and at least a part of the light is reflected by the reflecting surface and emerges from the second end surface;a reflection type optical modulating device for reflectively modulating the light from the second end surface and for forming a reflection light which has an image information;light deflecting means for deflecting the light from the second end surface of said optical means and guiding the deflected light to said reflection type optical modulating device;a projection lens for projecting the image from said reflection type optical modulating device onto a screen; anda condenser lens for converging the light modulated by said reflection type optical modulating device at a position of a stop of said projection means, said light deflecting means being disposed in the vicinity of the position of said stop of said projection means;wherein a position of the first end surface of said optical means and a position of the stop of said projection optical system are set in an optically conjugate relationship,a position of the second end surface of said optical means and a position of said reflection type optical modulating device are set in an optically conjugate relationship,said converging means has a paraboloidal reflector or an ellipsoidal reflector, wherein when said converging means has the paraboloidal reflector, said converging means has a convex lens for converging the light from the paraboloidal reflector and said light source is disposed at a focal point of said paraboloidal reflector, and when said converging means has the ellipsoidal reflector, said light source is disposed at a first focal point of said ellipsoidal reflector and the light source image is formed at a second focal point of said ellipsoidal reflector, andan optical system for setting the first end surface of said optical means and the position of said stop in the optically conjugate relationship, has first and second convex lens systems disposed between the second end surface of said optical means and said reflection type optical modulating device, and a third convex lens system disposed between said reflection type optical modulating device and the position of said stop wherein said optical system having said first convex lens system, said second convex lens system and said third convex lens system, forms an image of the first end surface of said optical means in the position of said stop so as to satisfy the following conditions:D1.gtoreq..beta..multidot.(2n1+1).multidot.L1.gtoreq.2.5 D1D1.gtoreq..beta..multidot.(2n2+1).multidot.L2.gtoreq.2.5 D2where .beta. is the image forming magnification of said optical system having said first convex lens system, said second convex lens system and said third convex lens system, L1 is the length of the first end surface in a long side direction of said reflection type optical modulating device, L2 is the length of the first end surface in a short side direction of said reflection type optical modulating device, n1 is the maximum number of reflections within said optical means in the long side direction of said reflection type optical modulating device, n2 is the maximum number of reflections within said optical means in the short side direction of said reflection type optical modulating device, D1 is the length of an aperture of said stop in the long side direction of said reflection type optical modulating device, and D2 is the length of the aperture of said stop in the short side direction of said reflection type optical modulating device.