Projector optical system, projector, and method for forming real image in use of projector optical system

摘要

A projector optical system for forming a real image by projecting an image of a display element has, sequentially from a screen side or an observation side, a first lens group having positive refractive power, an aperture diaphragm, a second lens group, and a third lens group having positive refractive power, with a diffractive optical element being provided on at least one of the first lens group and the second lens group which are adjacent to the aperture diaphragm. The projector optical system satisfies:0.05G/L0.9wherein G is an air gap on the optical axis between the second lens group and the third lens group, and L is a length on the optical axis, from the surface that is closest to the screen side to the display element.