| 摘要 |
PURPOSE:To realize reflected projection with a high reduction ratio by using an aplanatic surface, a concentric reflecting surface, and a concentric refracting surface in combination. CONSTITUTION:A reflected and reduced projection optical system has the 1st partial optical system K1 and 2nd partial optical system K2; and an enlarged image of a body on a body surface O is formed on an image surface I through the optical system I and an enlarged image is further formed on an image surface I' through the optical system K2. The optical system K1 has the 1st aplanatic lens LA1, the 1st reflecting surface M1, and the 2nd aplanatic lens LA2, and the optical system K2 has a concentric lens Lc, the 2nd, the 3rd, and the 4th reflecting surfaces M2, M3, and M4, and the 3rd aplanatic lens LA3. Centers of curvature of those reflecting surfaces nearly coincide with on-axis object point positions of the respective reflecting surfaces and centers of curvature of respective refracting surface except the aplanatic surfaces are nearly coincident on at on-axis object point positions of the respective refracting surfaces; and the property that the image magnification based upon the aplanatic surfaces is the square of the ratio of refractive indexes is utilized to realize projection of high magnification.
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