Ricoh Company, Ltd.

Akihiro Yamakage

Kazuhiro Fujita

Atsushi Takaura

Issei Abe

Osamu Nagase

Yoshitsugu Kohno

Seiichi Katoh

Koichi Ohtaka

Takeshi Nanjo

Masaaki Ishiyama

A projection optical system includes first and second optical systems. The first optical system includes a transmissive-refractive element and the second optical system includes a reflective-refractive element. An image formed by a spatial light modulator is projected by the projection optical system on a projection surface. A light beam that travels along an optical path that leads from the second optical system to the projection surface in an optical path between a center of the image formed by the spatial light modulator and the projection surface is projected at an angle with respect to a normal to the projection surface. An optical axis of the first optical system is folded to a folded position by an optical path deflecting unit in an area of the first optical system where the light beam entering the optical path deflecting unit is a converging light beam or a substantially parallel light beam.

Projection optical system

A projection optical apparatus capable of providing high image quality and having a reduced size is disclosed. The projection optical apparatus includes a light valve and a projection optical system including a first optical system having a transmissive-refractive element and a second optical system having a reflective-refractive element. An image formed on the light valve is projected by the projection optical system on a projection surface. The optical axis in the first optical system is folded both vertically and horizontally. The first group of the first optical system is contained in a space (dead space) whose lower limit is defined by a lower edge of the second optical system, thereby reducing the depth of the apparatus.

Projection optical apparatus

An optical system is disclosed, including: an optical deflecting array including a plurality of optical deflecting devices arranged in a two-dimensional array, each of optical deflecting devices displacing a member having an optical reflection area and deflecting light, so that an incoming light flux entering the optical reflection area is deflected to a reflection direction being changed, a light source illuminating the optical deflecting array, and a projection lens projecting reflected light from the optical deflecting array based on color information. Each of the optical deflecting devices deflects light to two-axis directions, incoming light fluxes having different colors enter each of the optical deflecting devices from two directions respectively corresponding to two deflection axes, and are reflected by each of the optical deflecting devices based on the color information; and each of reflected light fluxes is led to the projection lens for a respective arbitrary time.

Optical system, color information displaying method, optical deflecting device, and image projection displaying apparatus

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Iwate, Japan

Akihiro Yamakage