| CPC G02B 13/16 (2013.01) [G02B 17/0832 (2013.01)] | 11 Claims | 

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               1. An optical system configured to project a projection image formed on a reduction-side conjugated plane on an enlargement-side conjugated plane as an enlarged image, the optical system comprising: 
            a first optical system having a first optical element; and 
                a second optical system arranged at a reduction side of the first optical system, wherein 
                an intermediate image conjugated with the reduction-side conjugated plane and the enlargement-side conjugated plane is formed between the first optical system and the second optical system, 
                the first optical element has a first reflecting surface having a concave shape, 
                the second optical system has a first relay element, a second relay element arranged at an enlargement side of the first relay element, and a correction optical element arranged at the enlargement side of the second relay element, 
                the first relay element has a first relay reflecting surface having a concave shape, 
                the second relay element has a second relay reflecting surface having a convex shape, and 
                the correction optical element curves the intermediate image generated by the first relay element and the second relay element to reduce a field curvature generated by the first optical element. 
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