Olympus Corporation

Olympus Optical Company, Ltd.

Tohru Nakamura

Tetsuhide Takeyama

Hirofumi Tsuchida

The invention has now found out why ghost light occurs in an imaging optical system using a decentered reflecting prism for the purpose of reducing ghost light. The invention provides an imaging optical system comprising at least one decentered prismhaving a rotationally asymmetric reflecting surface, at least located on an image side of an aperture stop. The prismcomprises three or more surfaces including an entrance surface, a reflecting surfaceand an exit surface. The reflecting surface has an effective area A+B+C, and a reflection-enhancing member is applied onto an area B+C except a sub-area A at which an effective light beam is totally reflected.

Imaging optical system

An observation optical system comprises an image display elementand an eyepiece optical system which introduces an image formed by the image display elementto a center of an eye of an observer without forming an intermediate image, so as to allow the observer to observe the image as a virtual image. The eyepiece optical system is constructed and arranged to bend the optical axis using reflecting surfaces so as to be compact. The optical axis lies in a plane, with respect to which the optical system is formed symmetric. The optical system includes a prismhaving an entrance surface, a plurality of curved reflecting surfacesand an exit surface. The reflecting surfaceis provided with a volume hologram (HOE)Whereby, it is possible to provide an image observation optical system which can be made compact enough to be usable as an image display unit for a cellular phone or a portable intelligent terminal, and which can achieve high image definition and wide field angle while controlling chromatic aberration of magnification to be small.

Observation optical system using volume hologram

An observation optical system comprises an image display element and an eyepiece optical system which introduces an image formed by the image display element to a center of an eye of an observer without forming an intermediate image, so as to allow the observer to observe the image as a virtual image. The eyepiece optical system is constructed and arranged to bend the optical axis using reflecting surfaces so as to be compact. The image observation optical system can be made compact enough to be usable as an image display unit for a cellular phone or a portable intelligent terminal, and can achieve high image definition and wide field angle while controlling chromatic aberration of magnification to be small.

An observation optical system comprises an image display element and an eyepiece optical system which introduces an image formed by the image display element to a center of an eye of an observer without forming an intermediate image, so as to allow the observer to observe the image as a virtual image. The eyepiece optical system is constructed and arranged to bend the optical axis using reflecting surfaces so as to be compact. The optical axis lies in a plane, with respect to which the optical system is formed symmetric. The optical system includes a prism having an entrance surface , a plurality of curved reflecting surfaces and an exit surface . The reflecting surface is provided with a volume hologram (HOE) Whereby, it is possible to provide an image observation optical system which can be made compact enough to be usable as an image display unit for a cellular phone or a portable intelligent terminal, and which can achieve high image definition and wide field angle while controlling chromatic aberration of magnification to be small.

The invention relates to a zoom lens system of three-group construction, one lens for each group, which is less susceptible to aberration variations even upon zooming and can achieve entire-length reductions, large lens aperture and high zoom ratio. The zoom lens system comprises, in order from an object side thereof, a first lens group G consisting of one single lens formed of a homogeneous medium and having positive refracting power, a second lens group G consisting of one single lens formed of a homogeneous medium and having negative refracting power, and a third lens group G consisting of one single lens formed of a homogeneous medium and having positive refracting power. For zooming from a wide-angle end to a telephoto end of the zoom lens system, at least the second lens group G moves from the object side toward an image side of the zoom lens system.

Lens group zoom lens system, and display device having phototaking function

The invention relates to a zoom lens system of two-group construction, one lens for each group, which is less susceptible to aberration variations even upon zooming and can be much more increased in terms of lens aperture and zoom ratio. The zoom lens system of two-group construction comprises, in order from an object side thereof, a first lens group G having negative refracting power and a second lens group G having positive refracting power and in which a focal length thereof is varied by moving both the lenses while an optical axis separation therebetween is varied. The first lens group G consists of one concave lens having a strong concave surface directed toward an image plane side of the zoom lens system and formed of a homogeneous medium, and the second lens group G consists of one convex lens formed of a homogeneous medium. A stop S is located between the first lens group G and the second lens group G The first lens group G moves largely from the object side toward an image side of the zoom lens system while the second lens group G moves from the image side toward the object side during zooming from a wide-angle end to a telephoto end of the zoom lens system.

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Hachioji, Japan

Tohru Nakamura