Minolta Camera Kabushiki Kaisha

Minolta Company, Ltd.

Minolta Camera Co., Ltd.

Toshihiko Ueda

Kunihiko Konoma

Mitsutoshi Yagoto

Satoshi Iwasaki

Akiyoshi Hamada

Hiromu Nakamura

Nobuo Kanai

Haruhiro Hyodo

Muneo Kuroda

Kazuyuki Yoshida

Hiroki Kinoshita

Hiroaki Nakauchi

Tetsuji Niikawa

Keijiro Sakamoto

Kouitirou Tutiyasu

Sanae Watanabe

Kazuharu Kagoshima

Sanae Watanebe

A variable magnification lens system of the invention has from the object side a positive first lens unit and a negative second lens unit. The first lens unit includes a negative first lens element and a positive second lens element. The negative second lens unit includes a positive third lens element and a negative fourth lens element. At variable magnification from an equal magnification (1:1) state to an enlargement state, the overall lens system moves while the spacing between the two lens units is increased, and the distance between the object and the image remains constant. The object side surface of the first lens element and the image side surface of the fourth lens element are concave. Aspherical surfaces are provided on both surfaces of the first lens element and the image side surface of the third lens unit. The focal length of the first lens element and fourth lens element are suitable stipulated by a condition.

Variable magnification lens system

A radial gradient index lens system has a refractive index distribution. The refractive index decreases from an optical axis along a height. The lens system has two meniscus lens elements whose convex surfaces have a larger radius of curvature than concave surfaces. The meniscus lens elements are arranged symmetrically with respect to an aperture stop so that the convex surfaces thereof face an object side and an image side, respectively. The gradient index lens system is for use in a copying apparatus or as a reading optical system.

Gradient index lens system

A copying zoom lens system is provided with from the original side a first lens unit of negative refractive power including at least one negative lens element, a second lens unit of positive refractive power including at least four lens elements, and a third lens unit of negative refractive power including at least one negative lens element. The second lens unit is asymmetric with respect to the center of the lens units of the lens system. During zooming, the projection magnification is varied with the conjugate distance being maintained constant by varying the distance between the first and second lens units and the distance between the second and third lens units and by moving the entire lens system. The axial distances among the lens units are defined by predetermined conditions.

Copying zoom lens system

An image reading apparatus which does not require lens replacement and which satisfies the requirements of Kohler illumination regardless of changes in projection magnification. The image reading apparatus comprising an image reading device having a predetermined length in the main scanning direction for transforming an optical image projected thereon into analog image signals, a light source, condenser elements having an aspherical effect in the main scanning direction, thereby satisfying the requirements for Kohler illumination, and projection lens for projecting an image of an original illuminated by the light source onto the image reading device. A motor can move the projection lens and its pupil along the optical axis.

Image reading apparatus

An image reading apparatus for reading a projected image by a line sensor formed in a linear shape. An image reading apparatus has an illumination system, an original supporting member, a projection lens and a line sensor formed in a linear shape. The illumination system includes a light guide formed of a cylindrically shaped light-transmitting material, a light source for introducing light into the light guide from the lengthwise direction of the light guide, a light-diffusing portion formed on the circumference of the light guide in the lengthwise direction of the light guide and a slit portion positioned opposite the light-diffusing portion.

An nonvariable transverse magnification focussing method and lens system for maintaining a transverse magnification at a fixed value even when the movement distance of each lens group is quite small by moving the basis of the first lens group and the second lens group while maintaining the relationship therebetween with a suitable paraxial arrangement in accordance with specific principles.

Nonvariable transverse magnification focussing method and lens systems

A zoom lens system for use in a copying apparatus has first, second and third lens units of negative, positive and negative, respectively. Zooming is performed while the conjugate distance is kept constant by varying the distance between the first and second lens units and the distance between the second and third lens units and varying at a magnification either larger or smaller than unity the distance between the second and third lens elements of the second lens unit. The first lens unit has a lens element strongly concave to the object side. The second lens unit has a positive meniscus lens element, a bi-concave lens element and a bi-convex lens element. The third lens unit has a negative meniscus lens element concave to the image side.

Zoom lens system for use in a copying apparatus

An image projection apparatus including a projection lens system projecting an image of a transparent original onto an image receiving surface with a variable magnification and an illumination system illuminating the original. The projection lens system includes a plurality of projection lenses of different magnifications in an interchangeable manner or a zoom lens. The illumination system including a light source unit, a divergent lens unit and a convergent aspherical lens unit so that Kohler illumination can be realized in any magnification. A refracting power of the convergent aspherical lens unit becomes smaller than a spherical lens unit with an increase in a distance from an optical axis. The convergent aspherical lens unit may be includes a Fresnel lens.

Image projection apparatus

A projection lens system having a first positive lens group which includes a positive lens having a strongly convex surface facing the enlarged side and a negative lens, a seond negative lens group which includes a positive lens and a lens in the form of a negative meniscus lens having a concave surface facing the enlarged side, a third lens group which includes a lens in the form of a meniscus lens, wherein at least one lens surface is aspherical, having a concave surface facing the enlarged side, and a diaphragm is arranged between the first positive lens group and the second negative lens group, and wherein said projection lens system is standardized by the conditional expression to form compactly.

Projection lens system

A zoom lens system having a negative lens group which includes a negative lens having a concave surface facing the reducing side and a positive lens having a convex surface facing the enlarging side, and a positive lens group which includes a positive lens unit of at least one positive lens having a convex surface facing the enlarging side, a first lens having a concave surface facing the reducing side, a double convex lens, and a second lens having a concave surface facing the enlarging side, and wherein said zoom lens system is standardized by the conditional expression so that the pupil position on the reducing side approaches the image point on the reducing side.

Zoom lens system

A zoom lens system comprising, in order from an enlargement side, a first lens group of a negative power, a second lens group of a positive power and a third lens group of a positive power. The first lens group is fixed during a zooming operation from a longest focal length condition to a shortest local length condition and includes, in order from the enlargement side, a positive lens element, a negative lens element and an aperture stop. The second lens group includes two positive lens units which are movable independently of each other toward a reduction side during the zooming operation. The third lens group is also movable toward the reduction side during the zooming operation and includes, in order from the enlargement side, a positive lens element and a negative lens element.

Zoom lens system for use in a microfilm projection apparatus

A wide angle lens system having, from the object side, a first lens of a negative refractive power, a second lens of a positive meniscus lens, a third lens of a negative meniscus lens, a fourth lens of a positive meniscus lens, a diaphragm, a fifth lens being symmetrical with the fourth lens with respect to the diaphragm, a sixth lens being symmetrical with the third lens with respect to the diaphragm, a seventh lens being symmetrical with the second lens with respect to the diaphragm, and a eighth lens being symmetrical with the first lens. Each of the first and eighth lenses may have an aspherical surface in rotation symmetry with each other with respect to the diaphragm. Also, some of the lenses may be made of synthetic resin.

Wide angle lens system for use in copying machine

A zoom lens system comprising, in order from an enlargement side, a first lens group of a negative power, a second lens group of a positive power and a third lens group of a negative power. The first lens group is fixed during a zooming operation and includes, in order from the enlargement side, a positive lens element, a negative lens element and an aperture stop. The second lens group is movable toward a reduction side during a zooming operation and includes, in order from the enlargement side, a biconvex lens element, a negative meniscus lens element having a concave surface directed to the enlargement side, a positive lens element, a biconcave lens element and a biconvex lens element. The third lens group is also movable toward the reduction side during a zooming operation and includes, in order from the enlargement side, a biconcave lens element and a positive lens element.

An information record/pickup head assembly for an optical information recording and/or reproducing apparatus using an optical information storage disk, comprising a stationary optical unit and a movable optical unit movable with respect to the information storage disk loaded, wherein the stationary optical unit emits a beam of light toward the movable optical unit which then re-directs the incident beam toward the information storage disk while returning to the stationary optical unit the beam of light reflected from the information storage disk. A focusing operation is carried out in the stationary optical unit.

Optical information record/pickup head assembly

A zoom lens system for use in a microfilm projection apparatus, having from the enlargement side a first lens unit of a negative refractive power, a second lens unit of a positive refractive power and a third lens unit of a negative refractive power and including an aperture stop positioned within the second lens unit or in the vicinity thereof. The first lens unit consists of one or more meniscus lens elements each having a concave surface faced to the reduction side. The second lens unit includes, from the enlargement side, a lens group having at least two positive lens elements,a negative lens element and a positive lens element. The third lens unit consists of one or more meniscus lens elements each having a concave surface faced to the enlargement side. Zooming operation from the longest focal length side to the shortest focal length side is carried out by linearly moving both the second and third lens units to the reduction side along the optical axis while first lens unit is fixed. The zoom lens system fulfills the following condition:

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Toyokawa, Japan

Toshihiko Ueda