Projection optical system and image projecting apparatus

An image projecting apparatus comprising:

• an image forming element displaying image information on a conjugate plane A;
• an illuminating optical system illuminating the image forming element;
• and
• a projection optical system allowing plural light beams emitted from the image forming element to be obliquely incident on a conjugate plane B so as to form an enlarged image of an image formed by the image forming element on the conjugate plane B,
• wherein the projection optical system includes, at least,
• a first optical system,
• a second optical system,
• an intermediate image of the image forming element between the first optical system and the second optical system on which the plural light beams are generally converged,
• an optical system having a refractive power in the first optical system being composed of only a lens system transmitting the light beams,
• the intermediate image being formed by only a refractive power of the first optical system,
• the second optical system being a reflective optical system comprising a reflection mirror having a positive refractive power which reflects the light beams and is directly behind the intermediate image, and
• the first optical system is divided into a first lens group, a second lens group, and a third lens group by a stop and the third lens group includes a maximum lens distance space at the side of the conjugate plane B from the stop, and
• the first lens group, the second lens group, and the third lens group have respective positive, positive, and negative refractive powers in sequence from the side of conjugate plane A.