| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a projection optical system enhancing use efficiency of light in excellent balance and a projector incorporating the same. <P>SOLUTION: An optical modulation element side lens group includes a second lens group 40 and a third lens group 60, and has a different power each in vertical direction and in horizontal direction of a liquid crystal panel 18G (18R, 18B). Accordingly, as an entire system of a projection optical system 20, a focal distance is different in each of the vertical and the horizontal directions, and magnification is different in each of the vertical and horizontal directions, so that a horizontal/vertical ratio of an image on the liquid crystal panel 18G (18R, 18B) and a horizontal/vertical ratio of the image projected onto a screen SC can be made different. That is, with this projection optical system 20, it becomes possible to convert an aspect ratio, which is a ratio of width and height. There, a distance p between each focal point or diaphragm 70 and an end edge face of a screen SC side of the optical modulation element side lens group satisfies a predetermined conditional expression, so that telecentricity higher than a predetermined level can be secured in both a first operational state and a second operational state, each having a different horizontal/vertical ratio. <P>COPYRIGHT: (C)2013,JPO&INPIT |
