Ricoh Company, Ltd.

Ricoh Printing Systems, Ltd.

Hitachi Koki Co., Ltd.

Hitachi Printing Solutions, Ltd.

Yasuyuki Shibayama

Hibiki Tatsuno

Takanobu Osaka

Makoto Hirakawa

Kiichiro Nishina

Keiji Kataoka

Yohei Takano

Susumu Monma

Koji Doi

Masazumi Ouchi

Tetsuya Fujioka

Daisuke Ichii

Takeshi Mochizuki

Kazuhiro Akatsu

Yoshio Kubo

Masaru Hoshina

Jyun Ogino

Junichi Matsuno

An optical system includes a reflective optical system on a magnification side along an optical path of the projection optical system and a refractive optical system on a reduction side along the optical path. The reflective optical system includes one reflective optical element having a power. The refractive optical system includes a front group on the magnification side and a rear group on the reduction side. The front group having, in order from the magnification side toward the reduction side, a first lens group with a positive or negative refractive power, a second lens group, and a third lens group with a positive refractive power. The rear group has a positive refractive power. The first lens group moves to the magnification side, and the second lens group and the third lens group move to the reduction side in a change in focus from a long distance to a short distance.

Projection optical system, projection apparatus, and projection system

A magnification optical system forms an enlarged image of an object. It includes a refractive optical system including a plurality of lens groups; and a mirror train including a curved mirror, arranged in this order from an object side, a first focus structure configured to move the respective lens groups of the refractive optical system by different amounts along a normal line of a conjugate surface on the object side, and a second focus structure configured to move the respective lens groups along the normal line of the conjugate surface on the object side by different amounts from those of the first focus structure.

Magnification optical system

An image display device includes an image display element, a light source, an illumination system, a projector system comprising a refractive optical system including a plurality of lens groups, and a mirror train including a curved mirror, a first focus structure configured to move the respective lens groups of the refractive optical system by different amounts along a normal line of the image display element, and a second focus structure configured to move the respective lens groups along the normal line of the image display element by different amounts from those of the first focus structure.

Focus adjustment system for an image display device

An image display apparatus and an image display unit. The image display apparatus and the image display unit includes a light source configured to emit light, an illumination optical system including a luminous body forming device configured to form a secondary luminous body, the illumination optical system guiding the light emitted from the light source, an optical modulation element including a plurality of reflection planes to modulate the light guided by the illumination optical system, and a projection optical system including a projection lens system and a barrel storing the projection lens system, the projection optical system projecting the light modulated by the optical modulation element onto a projection plane. The barrel satisfies an equation &#x3c6;&#x3c;0.71H+8.5, where &#x3c6; denotes an outside diameter of a front end of the barrel on a light entering side and H denotes distance between the reflection planes and the front end of the barrel.

Image display apparatus and image display unit

An illumination unit includes a light source, an optical mixer to form secondary light sources from a light beam from the light source, and an illumination system to illuminate an optical modulator with the light beam from the optical mixer, including an optical element having an anamorphic surface, in which the optical element is rotated at a certain rotational angle about a rotational axis which is a normal line from a vertex of a surface of the optical element.

Illumination unit and image display device incorporating same

Disclosed is an enlargement optical system configured to form an image of an object at an enlargement side, including a lens system and a mirror system in order from a side of the object, the lens system including at least one lens, the mirror system including a first mirror and a second mirror in order from a side of the object, and the second mirror being an concave mirror, wherein an intermediate image conjugate to the object is formed at a side of the object with respect to the second mirror and the first mirror is held to be capable of adjusting a position thereof.

Enlargement optical system

Disclosed is an image displaying apparatus including an image displaying element configured to form an image to be projected and a projection optical system having a positive refractive power and configured to project the image to be projected onto a screen, wherein the projection optical system includes a lens optical system and a mirror optical system, the lens optical system including plural lens groups, the mirror optical system including a first mirror and a second mirror, the second mirror being a concave mirror, wherein an intermediate image of a pixel of the image displaying element is formed between the image displaying element and the second mirror, and wherein the first mirror is held to be capable of adjusting a position thereof.

Image displaying apparatus

An image displaying apparatus including a light source, an image displaying element configured to control exiting of incident light to display an image, an illumination optical system configured to illuminate the image displaying element with light exiting from the light source, and a projection optical system configured to project an image displayed on a display surface of the image displaying element, to provide an enlarged display. The projection optical system includes a lens optical system, a first mirror configured to reflect light transmitted through the lens optical system, and a second mirror configured to reflect light reflected from the first mirror toward the surface to be projected onto, and one of the mirrors is arranged at a position conjugate to the image displaying element, and wherein an optical surface of the one mirror is arranged to face vertically downward.

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Kanagawa, Japan

Yasuyuki Shibayama