To provide a projection optical system able to restrict adverse effect of heat generated by blocking light beams in a diaphragm, when used in a projector that enables image formation in which a slenderness ratio is adjusted by switching an aspect ratio, and to provide a projector incorporating the projection optical system.
An anamorphic optical system is employed, which has powers differing between the adjustment direction of a liquid crystal panel 18G whose second group 40 is an optical modulation element and the other directions of it. This enables the conversion of an aspect ratio, which is the ratio of width to height. Additionally, a diaphragm 70 is arranged between a first group 30, which is a magnifying optical system, and the second group 40, which is the anamorphic optical system. Thus, the diaphragm 70 can be cooled relatively easily. Also, the adverse effect of heat generated by blocking light beams on an optical member, as a result of the heat being transmitted to an optical member located in the vicinity of the diaphragm 70.
Osamu Suzawa
Kazuhiko Miyasaka
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