Konica Minolta Opto, Inc.

Tokuji Matsuda

Atsuo Masui

Shigeru Sawamura

Kohei Wataru

A video projection device has one of a plurality of types of projection lenses replaceably loaded and projects a video on a screen at a fixed position. The video projection device includes: a converter lens which is composed of a plurality of lenses, which is afocal as a whole, and which is detachably provided in front of the projection lens to convert projection magnification; and a gap adjustment mechanism changing a predetermined gap in the converter lens to a setting in accordance with at least one of a projection distance to the screen and the type of the projection lens loaded.

Video projection device having a converter lens attachably and detachably provided

A projection lens systemA enlarges and projects onto a screen, via a plurality of lenses Gto G, image light emitted from, a light sourceand modulated by DMDsto. A movable lens barrelholds the lens G, having positive power, which is positioned closest to the DMDsto. An outer tubeholds the movable lens barrelto enable movement in the optical axis direction. Through thermal deformation at the time of an increase in temperature, the bimetal membermoves the movable lens barrelin the optical axis direction so as to recede from the image formation devices which are the DMDsto

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Kishiwada, Japan

Tokuji Matsuda