Abstract: An optical system has a first optical axis on an incident side and a second optical axis on an exit side, and the first optical axis and the second optical axis are located at different positions. The optical system includes a reflection unit including a roof surface having a first reflection surface and a second reflection surface, and a third reflection surface parallel or orthogonal to a ridge line of the roof surface. The third reflection surface is different from the first reflection surface and the second reflection surface. The reflection unit is rotatable about the first optical axis.

Abstract: An optical system has a first optical axis on an incident side and a second optical axis on an exit side, and the first optical axis and the second optical axis are located at different positions. The optical system includes a reflection unit including a roof surface having a first reflection surface and a second reflection surface, and a third reflection surface parallel or orthogonal to a ridge line of the roof surface. The third reflection surface is different from the first reflection surface and the second reflection surface. The reflection unit is rotatable about the first optical axis.

Abstract: A zoom lens includes a negative lens unit arranged closest to an enlargement conjugate side among lens units having negative refractive power included in the zoom lens, at least one positive lens unit having positive refractive power arranged closer to the enlargement conjugate side than the negative lens unit, and a rear lens unit including at least one lens unit and arranged closer to a reduction conjugate side than the negative lens unit, wherein a distance between adjacent lens units is changed during zooming, a stop is arranged closer to the reduction conjugate side than the negative lens unit, the rear lens unit includes at least one positive lens, and the positive lens satisfies a predetermined condition.

Abstract: A zoom lens includes, in order from an enlargement side to a reduction side, a first lens unit having positive refractive power and not moving for zooming, a second lens unit having negative refractive power and moving for zooming, a stop, a zooming lens unit having positive refractive power and moving for zooming, and a final lens unit having positive refractive power and not moving for zooming. During zooming from a wide-angle end to a telephoto end, the second lens unit moves to the reduction side and the zooming lens unit moves to the enlargement side. The zooming lens unit includes a cemented lens. The cemented lens includes a negative lens and a positive lens cemented in order from the enlargement side. A cemented surface of the cemented lens has a convex shape on the enlargement side. The zoom lens satisfies predetermined conditions.

Abstract: A zoom lens includes, in order from an enlargement side to a reduction side, a first lens unit having positive refractive power and not moving for zooming, a second lens unit having negative refractive power and moving for zooming, a stop, a zooming lens unit having positive refractive power and moving for zooming, and a final lens unit having positive refractive power and not moving for zooming. During zooming from a wide-angle end to a telephoto end, the second lens unit moves to the reduction side and the zooming lens unit moves to the enlargement side. The zooming lens unit includes a cemented lens. The cemented lens includes a negative lens and a positive lens cemented in order from the enlargement side. A cemented surface of the cemented lens has a convex shape on the enlargement side. The zoom lens satisfies predetermined conditions.

Abstract: A zoom lens includes a negative lens unit arranged closest to an enlargement conjugate side among lens units having negative refractive power included in the zoom lens, at least one positive lens unit having positive refractive power arranged closer to the enlargement conjugate side than the negative lens unit, and a rear lens unit including at least one lens unit and arranged closer to a reduction conjugate side than the negative lens unit, wherein a distance between adjacent lens units is changed during zooming, a stop is arranged closer to the reduction conjugate side than the negative lens unit, the rear lens unit includes at least one positive lens, and the positive lens satisfies a predetermined condition.

Abstract: An image projecting apparatus includes an image display element, an optical system that projects an image displayed on the image display element onto a screen, an optical element that shifts in a direction perpendicular to an optical axis of the optical system, an adjusting mechanism that can shift the optical element in the direction perpendicular to the optical axis, and a holding member that fixes the optical element to a lens barrel, wherein a combined Abbe number vdch of materials of the optical element with respect to a d-line, a combined focal length fdch of the optical element with respect to the d-line, and the pixel pitch P of the image display element satisfy an appropriate condition.

Abstract: An image projecting apparatus includes an image display element, an optical system that projects an image displayed on the image display element onto a screen, an optical element that shifts in a direction perpendicular to an optical axis of the optical system, an adjusting mechanism that can shift the optical element in the direction perpendicular to the optical axis, and a holding member that fixes the optical element to a lens barrel, wherein a combined Abbe number vdch of materials of the optical element with respect to a d-line, a combined focal length fdch of the optical element with respect to the d-line, and the pixel pitch P of the image display element satisfy an appropriate condition.

Abstract: A zoom lens includes a negative lens unit having a negative refractive power, at least one positive lens unit having a positive refractive power, an intermediate lens unit including a stop, and at least one reduction side lens unit, in order from a magnification conjugate side to a reduction conjugate side, at least two magnification side movable lens units in the negative lens unit and the at least one positive lens unit, and at least one reduction side movable lens unit in the at least one reduction side lens unit are moved during zooming, and conditions of 0.9<(XT·?Tb·?W)/(XW·?Wb·?T)<1.1, 0.9<?W/?T<1.1, 0.8<(?TS·?Tb)/(?WS·?Wb)<1.2, and 1.4<fT/fW are satisfied.

Abstract: A zoom lens includes a negative lens unit having a negative refractive power, at least one positive lens unit having a positive refractive power, an intermediate lens unit including a stop, and at least one reduction side lens unit, in order from a magnification conjugate side to a reduction conjugate side, at least two magnification side movable lens units in the negative lens unit and the at least one positive lens unit, and at least one reduction side movable lens unit in the at least one reduction side lens unit are moved during zooming, and conditions of 0.9<(XT·?Tb·?W)/(XW·?Wb·?T)<1.1, 0.9<?W/?T<1.1, 0.8<(?TS·?Tb)/(?WS·?Wb)<1.2, and 1.4<fT/fW are satisfied.

Abstract: A color combining optical system according to this invention aims at reducing the size of an optical system and suppressing the occurrence of color unevenness. According to this invention, there is provided a color combining optical system for combining color light reflected by a dichroic film and color light transmitted through the dichroic film. The optical thickness of the dichroic film increases or decreases from one end side to the other end side in the inclining direction of the dichroic film with respect to the incident optical axis of the color light reflected by the dichroic film.

Abstract: A projector-type image display device includes a liquid crystal display device for forming an image, an illumination optical system for illuminating the liquid crystal display device with light from a light source, a projection optical system for projecting an image from the liquid crystal display device, and a diaphragm member disposed on at least one of the illumination optical system and the projection optical system. An aperture is formed in the diaphragm member, and the aperture has a shape such that the f-numbers at a plurality of directions from the at least one optical system are different f-numbers, according to contrast properties of each direction of the liquid crystal display device.

Abstract: A stereoscopic image pickup system for obtaining parallactic images of an object, the stereoscopic image pickup system includes a pair of, first and second, reflecting members each having a reflecting function, a pair of, first and second, amount-of-light control members arranged to respectively vary amounts of transmission of light fluxes coming from the first and second reflecting members alternately in a time-series manner, an optical member arranged to superpose an optical axis of a light flux having passed through the first reflecting member and the first amount-of-light control member and an optical axis of a light flux having passed through the second reflecting member and the second amount-of-light control member on one and the same optical axis, an image sensor for converting a light flux coming from the optical member into an electrical signal, and a controller for causing, on the basis of information on a distance to the object, an image taking-in area of the image sensor to differ between a first

Abstract: An eyepiece lens is constructed with, in order from an entrance side for light to an exit side for light, first, second, third, fourth and fifth lens units of negative, positive, positive, positive and positive refractive powers, respectively. Each of the first, second, third, fourth and fifth lens units of the eyepiece lens is composed only of one lens or a cemented lens, and an intermediate image by an objective lens is formed between the second lens unit and the third lens unit. An objective lens is constructed with, in order from an object side to an image side, first and second lens units of positive and negative refractive powers, respectively. The first and second lens units of the objective lens are composed of one positive lens and of one positive lens and one negative lens, respectively, and the various conditions are appropriately set. An optical apparatus includes the eyepiece lens, the objective lens and an erecting prism.

Abstract: A zoom lens for a camera having a between-the-lens shutter includes a motor for moving the lens along an optical axis in forward and rearward directions. A switch is operable by an operator to control operation of the motor for moving the lens from an initial position on the axis to a final stationary position that establishes the focal length of the lens. Control apparatus is responsive to the setting of the switch for operating the motor such that movement of the lens from its initial position to its final position always ends after the lens travels to its final position in a predetermined direction.

Abstract: An optical system includes a pair of front optical components, an optical member for superposing respective optical axes of the pair of front optical components on each other, a rear optical component disposed such that the superimposed optical axes coincide with an optical axis of the rear optical component, the rear optical component including a lens unit arranged to move during zooming, and a lens unit arranged to move during focusing and disposed on an object side of the lens unit arranged to move during zooming, and a pair of shutters capable of independently controlling amounts of transmission of light fluxes respectively entering the pair of front optical components from an object. The optical system forms parallactical images in a time-series manner by causing the pair of shutters to alternately change the amounts of transmission of light fluxes respectively entering the pair of front optical components from the object.

Abstract: Provided are a color combining optical element capable of forming a good projected image on a screen surface while permitting scaling-down of entire apparatus and a projection image display apparatus using it.

Abstract: In an illuminating device in which a light from a light source is separated into three color lights differing in optical path from one another by a color separating system, and light modulating elements conforming to the respective color lights are illuminated with the color lights, at least one of the optical paths of the three color lights has therein a reflecting system having positive power for reflecting the color light passing therethrough.

Abstract: A projector-type image display device includes a liquid crystal display device for forming an image, an illumination optical system for illuminating the liquid crystal display device with light from a light source, a projection optical system for projecting an image from the liquid crystal display device, and a diaphragm member disposed on at least one of the illumination optical system and the projection optical system. An aperture is formed in the diaphragm member, and the aperture has a shape such that the f-numbers at a plurality of directions from the at least one optical system are different f-numbers, according to contrast properties of each direction of the liquid crystal display device.

Abstract: A lighting device is disclosed which comprises an illuminating light source for illuminating an object, a first optical unit disposed on the side of the object of the illuminating light source and having an optical action section for diverging light or an optical action section for converging light, and a second optical unit disposed on the side of the object of the optical action section of the first optical unit and having an optical action section for exhibiting a characteristic opposite to a characteristic of the optical action section, wherein the optical action section of the second optical unit overlies the optical action section of the first optical unit in varying areas to change light distribution characteristic on the side of the object.