Olympus Corporation

Olympus Medical Systems Corporation

Azusa Noguchi

Shinichi Mihara

Hisashi Goto

Masahito Watanabe

Shinichi Nakamura

Hiroshi Ishii

Hideyasu Takato

Yuji Miyauchi

Susumu Takahashi

Kazuhiro Gono

Toru Miyajima

Nobuyuki Doguchi

Seiji Iwasaki

Hironobu Ichimura

Tsutomu Sasamoto

Masahiro Kawauchi

Kiyoshi Miyake

Hideaki Ishihara

An endoscope includes an imaging system and an illumination system. The illumination system includes a light guide and at least one illumination lens, and the imaging system includes an objective lens unit and an image pickup element. When a direction along a long side of the image pickup element is set to be a first direction, and a direction along a short side of the image pickup element is set to be a second direction, the illumination system is disposed at a position shifted in the second direction with respect to the imaging system.

Endoscope having an illumination system shifted with respect to an imaging system to reduce generation of heat at a front-end portion of the endoscope

Provided is an endoscope objective optical system including, in order from an object side, a first group having negative refractive power, a second group having positive refractive power, and a third group having positive refractive power. The second group is provided so as to be movable in an optical-axis direction. The following conditional expression is satisfied,9&#x3c;2/&#x3c;16&#x2003;&#x2003;(1)where f2 is a focal length of the second group, and fa is a focal length of the entire system in the normal observation state.

Endoscope objective optical system

An endoscope system has a light source apparatus and an endoscope including an illumination optical system and an objective optical system. At least the objective optical system of the endoscope is provided with an adjustable diaphragm, and in a light path in one of the light source apparatus, the illumination optical system, and the objective optical system, an insertable/retractable filter for observation for special light is provided. The adjustable diaphragm performs a closing operation or an opening operation only when the filter for observation for special light is inserted into the light path.

Endoscope system and lens unit

An endoscope objective optical system used in an endoscope has an objective optical system including a first lens group having a positive refractive power, an aperture stop, a second lens group having a negative refractive power and a third lens group having a positive refractive power, the first lens group, the aperture stop and the second and third lens group being successively disposed from the object side. The second lens group is made movable along an optical axis to change the focal length of the objective optical system. The lens surface at the object-side outermost position in the first lens group is formed so as to be convex on the object side.

A zoom optical system includes, in order from the object side, a first lens unit with positive refracting power, a second lens unit with negative refracting power, a third lens unit with positive refracting power, and a fourth lens unit with positive refracting power. An aperture stop is interposed between the second lens unit and the fourth lens unit. Upon zooming, at least, the first lens unit, the second lens unit, and the third lens unit are moved so that spacings between these lens units are varied. The first lens unit is constructed with at most two lens elements. The second lens unit includes, in order from the object side, a first negative lens in which the image-side surface is greater in curvature than the object-side surface, an air spacing, a second negative lens in which the image-side surface is greater in curvature than the object-side surface, an air spacing, and a positive lens in which the object-side surface is greater in curvature than the image-side surface. The second negative lens is constructed to satisfy the following condition:&#x2212;0.7&#x3c;23&#x3c;0.05where r23 is the radius of curvature of the object-side surface of the second negative lens and fis the focal length of the second lens unit.

Zoom optical system and imaging apparatus using the same

The invention relates to an imaging system in which, while high image quality is maintained with the influence of diffraction minimized, the quantity of light is controlled, and which enables the length of the zoom lens to be cut down. The imaging system comprises a zoom lens comprising a plurality of lens groups Gand Gwherein the spacing between individual lens groups is varied to vary a focal length and an aperture stop located in an optical path for limiting at least an axial light beam diameter, and an electronic image pickup device I located on the image side of the zoom lens. The aperture stop has a fixed shape, and a filter Sfor performing light quantity control by varying transmittance is located on an optical axis of a space located at a position different from that of a space in which the aperture stop is located.

Imaging system

A zoom optical system includes, in order from the object side, a first lens unit with positive refracting power, a second lens unit with negative refracting power, a third lens unit with positive refracting power, and a fourth lens unit with positive refracting power. An aperture stop is interposed between the second lens unit and the fourth lens unit. Upon zooming, at least, the first lens unit, the second lens unit, and the third lens unit are moved so that spacings between these lens units are varied. The first lens unit is constructed with at most two lens elements. The second lens unit includes, in order from the object side, a first negative lens in which the image-side surface is greater in curvature than the object-side surface, an air spacing, a second negative lens in which the image-side surface is greater in curvature than the object-side surface, an air spacing, and a positive lens in which the object-side surface is greater in curvature than the image-side surface. The second negative lens is constructed to satisfy the following condition:&#x2212;where ris the radius of curvature of the object-side surface of the second negative lens and fis the focal length of the second lens unit.

The invention relates to a zoom optical system wherein various aberrations are corrected while the total thickness of a lens arrangement upon received at a collapsible lens mount is reduced thereby ensuring compactness, high image-formation capabilities, and high zoom ratios at the wide-angle end, and an imaging system that incorporates the same. The zoom optical system comprises a first lens group Gof negative refracting power and a second lens group Gof positive refracting power. The first lens group Gcomprises a negative single lens comprising at least one aspheric surface and a positive single lens with an air separation interposed between the negative single lens and the positive single lens. The second lens group Gcomprises a positive lens, a cemented lens consisting of a positive lens and a negative lens and a positive lens, and comprises at least one aspheric surface. Zooming is carried out by varying a spacing between the respective lens groups. The zoom optical system satisfies condition (1) that defines the proper range of the refracting power profile for the first lens group G, condition (2) that defines an angle-of-view range at the wide-angle end, and condition (3) that defines an angle-of-view range at the telephoto end.

Zoom optical system, and imaging system incorporating the same

The invention provides a zoom lens that operates in such a zooming mode and zoom arrangement that the number of lens elements is reduced to make the total thickness of each lens group thin while stable yet high image-formation capability is maintained, thereby achieving thorough size reductions in video cameras or digital cameras, and an electronic imaging system using the same. The zoom lens comprises a first lens group G of negative refracting power, a second lens group G of positive refracting power and a third lens group G of positive refracting power. For zooming from the wide-angle end to the telephoto end of the zoom lens upon focused on an infinite object point, the second lens group G moves toward the object side alone of the zoom lens, and the third lens group G moves in a locus different from that of the second lens group while the spacing between adjacent lens groups varies. The second lens group G is composed of two lens components, i.e., an object side-lens component and an image side-lens component, one of which is composed of a cemented lens component consisting of a positive lens element and a negative lens element, and the other consists only of a single lens component. The object side-lens component satisfies condition (1) concerning the axial radius-of-curvature ratio between the object side-surface and the image side-surface.

Growing community of inventors

Hino, Japan

Azusa Noguchi