Abstract: A variable magnification optical system comprises at least three optical units which are a first moving optical unit, a fixed optical unit and a second moving optical unit. The three optical units are arranged in that order in a propagation direction of light, and a variation of magnification is effected by a relative movement between the first moving optical unit and the second moving optical unit.

Abstract: An image pickup optical system includes an optical unit having a light incidence surface on which a light is incident, a light reflecting surface reflecting the light incident from the light incidence surface and having a curvature, and a light emergence surface from which the light reflected by the light reflecting surface emerges, and a transparent optical member disposed near the surface position of at least one of the light incidence surface and the light emergence surface. The optical member is adhesively fixed to the optical unit to thereby make any special holding member for the optical member relative to the optical unit unnecessary.

Abstract: A variable magnification optical system comprises at least three optical units which are a first moving optical unit, a fixed optical unit and a second moving optical unit. The three optical units are arranged in that order in a propagation direction of light, and a variation of magnification is effected by a relative movement between the first moving optical unit and the second moving optical unit.

Abstract: An optical apparatus includes an optical unit including a light entrance surface, light reflecting surfaces and a light exit surface all of which are integrally formed of transparent material, and the optical unit has in its interior an internal refracting surface for refracting light. Since a light beam passes through the optical unit from the light entrance surface to the light exit surface via the internal refracting surface and the light reflecting surfaces along a bent optical path, the optical apparatus is reduced in size and improved in optical performance, particularly, well corrected in chromatic aberration. Another disclosed optical apparatus is arranged to achieve zooming by using a plurality of optical units each of which is similar to the aforesaid optical unit.

Abstract: A zoom lens comprises a plurality of optical elements each of which includes a transparent body having two refracting surfaces and a plurality of reflecting surfaces and is arranged so that a light beam enters the transparent body from one of the two refracting surfaces, repeatedly undergoes reflection, and exits from the other of the two refracting surfaces, and/or a plurality of optical elements on each of which a plurality of reflecting surfaces made from front surface mirrors are integrally formed, and each of which is arranged so that an entering light beam repeatedly undergoes reflection by the plurality of reflecting surfaces and exits from the optical element.

Abstract: In an optical element for reflecting light from an incidence surface of the optical element by one or more reflecting surfaces comprising off-axial curved surfaces, and causing the light to emerge from an emergence surface, at least one of the incidence surface, the emergence surface and the reflecting surface diffracting the light.

Abstract: An objective lens including first, second, third, and fourth lens units in order from the object side. The first lens unit consists of a first lens of negative refractive power in the shape of a meniscus with a concave surface toward the image field side. The second lens unit consists of a second lens of positive refractive power. The third lens unit consists of a composite lens having joined together a third lens of negative refractive power with a concave surface toward the object side and a fourth lens of positive refractive power with a convex surface toward the image field side, the third lens unit having as a whole negative refractive power. The fourth lens unit consists of a fifth lens of positive refractive power. The objective lens has a predetermined condition for focal length.

Abstract: The present invention relates to an image displaying apparatus comprising an image displaying device for radiating light to display an image, a first optical system for forming the image on a primary image plane, which has a magnification-changing portion for changing an image magnification of the image and a second optical system for guiding light from the primary image plane to the pupil of an observer in order to enable the observer to observe an enlarged, virtual image of the image formed on the primary image plane.

Abstract: A reflecting-type optical system according to the invention includes an optical element composed of a transparent body having an entrance surface, an exit surface and at least three curved reflecting surfaces of internal reflection. A light beam coming from an object and entering at the entrance surface is reflected from at least one of the reflecting surfaces to form a primary image within the optical element and is, then, made to exit from the exit surface through the remaining reflecting surfaces to form an object image on a predetermined plane, In the optical system, 70% or more of the length of a reference axis in the optical element lies in one plane.

Abstract: A variable magnification optical system comprising four optical units each having a reflecting surface inclined with respect to a reference axis ray which is a ray passing from an aperture center of an aperture stop to a center of a final image plane, the variable magnification optical system being arranged to perform a magnification varying operation by moving at least two of the four optical units along the reference axis ray in such a manner as to vary an optical path length which extends along the reference axis ray from a predetermined position on an object side to the final image plane.

Abstract: A zoom optical system and an image pickup apparatus using the same are disclosed. The zoom optical system comprises a first optical unit having a refractive power, the first optical unit having a reflecting surface, a second optical unit having a refractive power, and a driving portion for moving a light receiving surface which receives light from an object through the first optical unit and the second optical unit. The zoom optical system performs variation of magnification by moving at least one of the first optical unit and the second optical unit, and a deviation of a focus position due to the variation of magnification is corrected by the light receiving surface being moved by the driving portion.

Abstract: A zoom lens includes, in order from an object side to an image side, a first lens unit of positive refractive power, a second lens unit of negative refractive power, a third lens unit of positive refractive power, the third lens being composed of a single lens, and a fourth lens unit of positive refractive power, the fourth lens unit being composed of not less than four lenses including at least one negative lens, wherein, during zooming, the first lens unit and the third lens unit are stationary and the second lens unit and the fourth lens unit move along an optical axis.

Abstract: The present invention relates to an image displaying apparatus, which comprises a display unit for modulating light incident thereinto in accordance with image information and reflecting the light, an illuminating device for emitting light, and an optical system for guiding a beam of light from the illuminating device into the display unit and guiding a beam of reflected light from the display unit to the observer's pupil located at a position different from that of the illuminating device.

Abstract: A zoom lens comprises a plurality of optical elements each of which includes a transparent body having two refracting surfaces and a plurality of reflecting surfaces and is arranged so that a light beam enters the transparent body from one of the two refracting surfaces, repeatedly undergoes reflection, and exits from the other of the two refracting surfaces, and/or a plurality of optical elements on each of which a plurality of reflecting surfaces made from front surface mirrors are integrally formed, and each of which is arranged so that an entering light beam repeatedly undergoes reflection by the plurality of reflecting surfaces and exits from the optical element.

Abstract: A variable magnification optical system comprises at least three optical units which are a first moving optical unit, a fixed optical unit and a second moving optical unit. The three optical units are arranged in that order in a propagation direction of light, and a variation of magnification is effected by a relative movement between the first moving optical unit and the second moving optical unit.

Abstract: This invention velates to an image displaying apparatus which includes a plurality of image displaying devices for displaying respective display images on display surfaces thereof, reflecting surfaces provided in correspondence to the respective image display devices, each for reflecting a light beam from the corresponding image display device and an optical system for guiding light beams from the plurality of reflecting surfaces to a pupil of an observer.

Abstract: An display apparatus has an image displaying device for modulating light by a spatial light modulation element and displaying an image, a relay optical system for forming the image on an imaging plane at a location differing from the image displaying device, an eyepiece optical system for directing the light from the imaging plane to an observer's pupil, and light beam controlling device provided in a portion of the relay optical system for controlling the amount of transmission of a light beam from the image displaying device correspondingly to the inclination of the contrast distribution of the light beam.

Abstract: Provided is an image sensing apparatus in which it is possible to use an optical system having a large aperture and an image sensing system such as an image sensing element in an image sensing cartridge docked with a portable image device. The image sensing apparatus includes a portable information device and an image sensing cartridge, which has at least an image sensing system, capable of being loaded in and unloaded from the information device. An image sensing operation becomes possible by docking the information device and the image sensing cartridge. The image sensing cartridge has an opening, which is for introducing light to the image sensing system, the aperture of which is designed to be larger than the shortest portion of an insertion port, which is provided in the information device, for inserting the image sensing cartridge.

Abstract: The present invention relates to an image display apparatus disposed near an observer's head for observing an image displayed on image display means as an enlarged virtual image. The apparatus has a relay optical system for causing the displayed image by the image display means to be intermediately formed, the relay optical system having at least one decentered reflecting surface for bending a light beam from the image display means, and at least one lens of an anamorphic aspherical shape differing in curvature in any orthogonal direction, and an eyepiece optical system for directing the image by the relay optical system to the observer's pupil, the eyepiece optical system having at least one decentered reflecting surface which is an anamorphic aspherical surface of a concave surface shape for bending the light beam from the relay optical system.

Abstract: An image display apparatus comprises an image display device for emitting a light beam to display an image, and an observation optical system for guiding the light beam from the image display device to the pupil of an observer. The observation optical system has at least a concave, reflective surface and a convex, reflective surface in order from the pupil side of the observer along an optical axis of the light beam directed from the image display device to the pupil. The concave, reflective surface is located near the pupil.