Abstract: In a rod lens array in which a plurality of rod lenses each having a refractive-index distribution in the radial direction are arranged in one row such that the optical axes are parallel to each other, and in a life-size imaging optical apparatus using the rod lens array, the outside diameter of each rod lens is such that 0.05 mm.ltoreq.R.ltoreq.0.25 mm and 0.5R.ltoreq.r.sub.0 .ltoreq.1.0R (2R: the distance between the optical axes of adjacent rod lenses and r.sub.0 : the radius of the effective area of each rod lens that provides a lens action) and the degree of overlap m defined by m=x.sub.0 /2R is such that 1.61.ltoreq.m.ltoreq.1.80 or 2.06.ltoreq.m.ltoreq.2.50 where X.sub.0 is the view radius of a single rod lens which is given by X.sub.0 =-r.sub.0 /cos(Z.sub.0 .pi./P).

Abstract: A lens system composed of a first lens unit which is composed of at least a positive lens component and at least a negative lens component, and a second lens unit which comprises at least one positive lens component. The lens system is composed of a small number of lens components and configured to be compact by disposing at least one radial type gradient index lens component in the second lens unit and selecting an adequate refraction index distribution for the radial type gradient index lens component.

Abstract: This invention proposes the fabrication of a polarization-independent air-path isolator based on a beam aperture method. The isolator includes a micro Grin lens (MGL) and three small Grin lenses (SGLs). These lenses focus and collimate the forward and backward beams from the input and output ends of the isolator. In addition, one of the small Grin lenses (SGLs) also acts as a beam expander for the backward beam. Due to the significant difference in widths between the forward and backward collimated beams, the optical power of the forward beam is almost completely collected by the output small Grin lens (SGL) at the output end, while only a very small percentage of the optical power of the backward beam is collected by the small Grin lens (SGL) at the input end. Since a laser beam, in general, has a Gaussian beam-intensity distribution, positioning the micro Grin lens (MGL) at an off axis position will significantly enhance the isolation characteristic of the isolator.

Abstract: A zoom lens system has a plurality of lens units. Zooming is performed by varying distances between the lens units. A gradient index lens is included in the lens units. The gradient index lens has a gradient index in a direction vertical to an optical axis. The gradient index lens has at least one aspherical surface.

Abstract: In a rod lens array in which a plurality of rod lenses each having a refractive-index distribution in the radial direction are arranged in two rows such that the optical axis for one row is parallel to that for the other row, and in a life-size imaging optical apparatus using the rod lens array, the outside diameter of each rod lens is such that 0.05 mm.ltoreq.R.ltoreq.0.25 mm and 0.5R.ltoreq.r.sub.0 .ltoreq.1.0R (2R: the distance between the optical axes of adjacent rod lenses and r.sub.0 : the radius of the effective area of each rod lens that provides a lens action) and the degree of overlap m defined by m=X.sub.0 /2R is such that 1.46.ltoreq.m.ltoreq.1.64 (where X.sub.0 is the view radius of a single rod lens which is given by X.sub.0 =-r.sub.0 /cos(Z.sub.0 .pi./P).

Abstract: A segmented GRIN anamorphic lens and a lens array using such lenses are provided. The lens has an optical axis and is composed of a plurality of segments. The interfaces between the segments are planes or wedges inclined at an angle to the optical axis. At least one segment has a predetermined axial index of refraction profile while the other segment may have either a predetermined homogeneous index of refraction or a predetermined radial index of refraction profile. The planar interface geometry and the index of refraction profiles are chosen to provide lenses with desirable optical properties. Spherical and cylindrical aberrations can be reduced or eliminated by appropriate choice of the index of refraction profile. The front and rear surfaces of the lens assembly can also be ground and polished into spherical shapes which act with the axial gradient interface to yield an anamorphic lens functionality.

Abstract: Optics using a graded-index lens, comprising: a single graded-index lens and a homogeneous plano-convex lens. The single graded-index lens has a refractive index distribution in a radial direction, wherein the graded-index lens has a plane or convexo-spherical lens surface and when its refractive index distribution is expressed byn(r).sup.2 =n.sub.0.sup.2 .multidot.{1-(g.multidot.r).sup.2 +h.sub.2 (g.multidot.r).sup.4 +h.sub.6 (g.multidot.r).sup.6 +h.sub.8 (g.multidot.r).sup.8 +.multidot..multidot..multidot.}the following conditions are satisfied,1.45.ltoreq.n.sub.0 .ltoreq.1.80, and0.45.ltoreq.n.sub.0 .multidot.r.sub.0 .ltoreq.0.90,where r is the distance from the optical axis, n(r) is the refractive index at the position distant by r from the optical axis, n.sub.0 is the refractive index on the optical axis, r.sub.0 is the radius of the graded-index lens, g is an index distribution coefficient, and h.sub.4, h.sub.6 and h.sub.8 are index distribution coefficients.

Abstract: An optical coupler is provided that comprises a single lens component, comprising two axially-graded index of refraction elements, each having a low refractive index surface and a high refractive index surface and joined along their respective high refractive index surfaces. As configured, the optical coupler is useful as a solar concentrator for concentrating solar radiation onto a solar cell or other solar-receptive medium.

Abstract: An achromatic lens system which comprises a radial type gradient index lens which has a refractive index varying in a direction perpendicular to an optical axis and a diffraction type lens, and sufficiently corrects the secondary spectrum with a small number of optical elements.

Abstract: A graded-index microcylindrical lens functioning in combination with a laser diode beam to change the divergence of the fast axis on an incoming laser beam from one divergence to another, but not to collimate the beam. In one embodiment of the present invention, the graded-index microcylindrical lens changes the divergence of one axis of the laser beam to be substantially equal to the divergence of the slow axis.

Abstract: A gradient index lens component composed of a single radial type gradient index lens element which has planar surfaces on both side and a positive refractive power and comprising an aperture stop which is disposed in the vicinity of an object side surface of the radial gradient index lens element for restricting a light bundle. And an image pickup apparatus composed by integrating the gradient index lens component with an image pickup device.

Abstract: A stereoscopic-vision endoscope of the present invention comprises a tubular elongated insertional part, an objective optical system situated in the insertional part, a relay optical system situated in the insertional part for transmitting an object image formed by the objective optical system, a pupil dividing stop for dividing a light beam emanating from an object image formed by the relay optical system into a plurality of portions, an image formation optical system for receiving light beams from the pupil dividing stop so as to form a plurality of object images having parallax, and imaging devices for picking up the object images formed by the image formation optical system. The relay optical system satisfies the condition .phi..sup.2 /L>0.43 (where .phi. denotes an outer diameter of a system of relay lenses, and L denotes a relay length of the relay optical system).

Abstract: An optical system comprising a radial type gradient index lens component which has a refractive index distribution in a radial direction from an optical axis in a medium thereof, and configured to correct chromatic aberration sufficiently favorably by selecting a difference between a partial dispersion ratio on the optical axis and that on an effective diameter when a gradient of the distribution of the radial type gradient index lens component is different dependently on wavelengths.

Abstract: A method for designing an objective lens apparatus formed by at least two lenses, a first lens and a second lens, which includes the steps of: measuring aberration which occurs when a light beam is converged by the first lens; setting the first lens is set such that the aberration occurring in the first lens satisfies Marechal's criterion, in accordance with the measurement results; measuring aberration which occurs when a light beam is converged by the first lens and the second lens; and setting the second lens such that the aberrations occurring in the first lens and the second lens satisfy Marechal's criterion, in accordance with the measurement results. Accordingly, an objective lens apparatus with a small aberration and a large numerical aperture NA can be designed by this method.

Abstract: A scanning optical system which includes a light source for emitting a beam of light, a light deflector for deflecting the beam of light in a main scanning direction, and a scanning lens which receives a beam of light deflected by the light deflector for focusing the deflected beam of light onto a scanning surface. The scanning lens includes a lens having a refractive index distribution in either the main or the sub-scanning direction.

Abstract: An optical device having a variable index of refraction across its surface includes a light transmissive material with a plurality of regions in the light transmissive material. Each region has an index of refraction which is different from the remainder of the material. The regions may be arranged in the surface of the material such that the density of the regions on the surface varies across the surface. Each region may be a bore, including a hole that extends through the light transmissive material. Variations in the density of the regions or bores as well as the depth and shape of the bores may be utilized to create variations of the refractive index within the light transmissive material. The regions form a refractive lens.

Abstract: An image transmission optical system comprising a relay lens system for a single image relaying cycle which has a magnification of approximately 1.times. and comprises at least one radial gradient-index lens element having a refractive index distribution expressed by the formula (a) shown below and satisfying the following condition (1), thereby favorably correcting logitudinal chromatic aberration produced by the relay lens system for a single image relaying cycle.N(r)=N.sub.00 +N.sub.10 r.sup.2 +N.sub.20 r.sup.4 + . . . (a)1/V.sub.10 <1/V.sub.

Abstract: An axially-based lens is provided, comprising two biaxial elements, each having entrance and exit surfaces. The exit surface of one of the elements is joined to the entrance surface of the other element, with one of the elements rotated at an angle with respect to the other. In a preferred embodiment, the angle of rotation is 90.degree.. The axially-based lens thus comprises four axial sub-elements, and is called a "quadaxial" lens herein. The axially-based lens element has the ability to gather and focus light to a spot with a minimum of spherical aberration and with a substantially uniform distribution of light intensity from center to periphery of the spot. In a preferred embodiment, the lens element focuses light to a square spot size.

Abstract: An optical device is disclosed wherein a first GRIN lens and a second GRIN lens having their optical axes offset. The first GRIN lens has one or more input ports at an input end. The second GRIN lens is disposed to receive light from the first GRIN lens. A reflecting surface is coated onto a second end face of the second GRIN lens or alternatively is disposed adjacent to the second end face and positioned to reflect an input beam of light launched into the input end face of the first GRIN lens. The reflective surface is at a location where light incident upon it to be returned to the first GRIN lens is collimated. By placing a filter and third GRIN lens between the first and second lenses double filtering may be achieved at the pass band or pass wavelength of the filter. Furthermore, the more simple arrangement including only first and second lenses provides a means of directing light into and out of the device at different angles or directions with respect to the optical axis of the first lens.

Abstract: At least one metal species g is selected from the metal group G consisting of Nb, Ta, Pb, Ti, Tl and Zr. At least one metal species f is selected from the metal group F1 consisting of La, In, Y, Zr and Ta. The metal species g and f are not simultaneously Ta or Zr. The metal species g and f have concentrations distributed in mutually reverse directions. The element exhibits a ratio of dCf/dCg, in which dCf and dCg represent concentration distribution gradients of metal species f and g, respectively, ranging from -4 to -0.2. Alternatively, at least one metal species f may be selected from the metal group F2 consisting of Ga, Sn, Ba, Sr and Ca, while causing the ratio of dCf/dCg to be in the range of from -7 to -0.5. Thus, a gradient index optical element is obtained, which exhibits less refractive index change and large Abbe number change and is hence superior to conventional elements in correction of chromatic aberration.

Abstract: An objective lens system for microscopes composed of only two lens components each of which is a radial type graded refractive index lens component, and having a numerical aperture of at least 0.2 and favorably corrected aberrations.

Abstract: An optical system comprising a plural number of lens elements at least one of which is designed as a graded refractive index lens element having refractive index distribution in the radial direction, and has aberrations favorably corrected in said optical system as a whole by making most of the correcting functions of the graded refractive index lens element for Petzval's sum and chromatic aberration.

Abstract: A stereomicroscope comprising an objective lens system and eyepiece lens systems, the objective lens system comprising at least two lens units, permitting a working distance thereof by varying at least one airspace and having a concave surface at a location farthest from an object to be observed so as to minimize lowering of the magnification of the stereomicroscope and stereoscopic impressions of images observed through the stereomicroscope.

Abstract: An optical element having an optical axis, and comprising a plurality of definable adjacent zones of optical material, each zone having a definable refractive index different from the refractive index of an adjacent zone and an Abbe number, the zones of optical materials being arranged parallel to each other to define a profile of refractive indices which is symmetric about a plane of symmetry along the optical axis of the element and parallel to the zones. In one embodiment the optical element is a spectrally invariant lens.

Abstract: An optical system for a compound camera includes an equivalent image plane provided at a position substantially optically equivalent to an image plane of the photographing lens system. A condenser lens is provided proximate to the equivalent image plane and a relay lens system is provided behind the condenser lens to form an image of the photographing lens system on an image pickup device. The relay lens system satisfies the requirements defined by -0.1<P<0.09, and S3<0, where P designates the Petzval sum of the whole relay lens system when the focal length of the relay lens system is assumed to be 1.0, and S3 designates the astigmatism coefficient of the whole relay lens system when the focal length thereof is assumed to be 1.0, respectively.

Abstract: An improved spherical gradient lens and a method of fabricating same. A uniform sphere of a material such as high density irradiated polystyrene or a methylpentene copolymer in the polyolefin family having a uniform relative dielectric constant is provided. A plurality of radially extending holes are formed therein, for example by drilling, the holes having a predetermined cross sectional geometry along axes extending radially from the center of the sphere. The geometry of holes is selected to control the resultant local density of material, and thus the relative dielectric constant as a function of distance from the center of the sphere. Hole diameters are chosen so as to be small compared to the shortest wavelength of interest with which the lens will be used.

Abstract: Disclosed is a nonfull aperture Luneburg-type lens for correction of an adjacent light source. The lens includes a core having a circular cross-section and a graded refractive index, and a cladding enclosing the core. The cladding has a circular cross-section and a homogenous refractive index. Also disclosed is a method for forming the nonfull aperture Luneburg-type lens with a graded index core and a homogenous cladding, and a high numerical aperture laser diode assembly including the nonfull aperture Luneburg-type lens.

Abstract: 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.

Abstract: Disclosed is a nonfull aperture Luneburg-type lens for correction of an adjacent light source. The lens includes a core having a circular cross-section and a graded refractive index, and a cladding enclosing the core. The cladding has a circular cross-section and a homogenous refractive index. Also disclosed is a method for forming the nonfull aperture Luneburg-type lens with a graded index core and a homogenous cladding, and a high numerical aperture laser diode assembly including the nonfull aperture Luneburg-type lens.

Abstract: An optical device having a variable index of refraction across its surface includes a light transmissive material with a plurality of regions in the light transmissive material. Each region has an index of refraction which is different from the remainder of the material. The regions may be arranged in the surface of the material such that the density of the regions on the surface varies across the surface. Each region may be a bore, including a hole that extends through the light transmissive material. Variations in the density of the regions or bores as well as the depth and shape of the bores may be utilized to create variations of the refractive index within the light transmissive material.

Abstract: An optical system comprising a plural number of lens elements at least one of which is designed as a graded refractive index lens element having refractive index distribution in the radial direction, and has aberrations favorably corrected in said optical system as a whole by making most of the correcting functions of the graded refractive index lens element for Petzval's sum and chromatic aberration.

Abstract: An optical system includes a refractive index distribution type optical element which configuration is formed to be a parallel plane plate. The refractive index distribution is provided in the radial direction perpendicular to an optical axis of the optical system, in which the refractive index is increased and a color dispersion value .nu.d is decreased as a location on the optical element is farther away from the optical axis. The optical element is combined with a lens or a plurality of lenses, the refractive index of which is homogeneous, so that a chromatic aberration generated by the homogeneous refractive index lens can be compensated. When the refractive index distribution in the radial direction perpendicular to the optical axis is expressed by the following expression,n=n.sub.0 i+n.sub.1 ih.sup.2 +n.sub.2 h.sup.4where h is the height from the optical axis and i is the wave length respectively illustrated by lines d, F and C, then the following expression is satisfied,.nu.dG=n.sub.1 d/(n.sub.1 F-n.

Abstract: An optical system comprising, in the order from the object side, an objective lens unit having a positive refractive power, a relay lens unit having a positive refractive power and an eyepiece lens unit having a positive refractive power, adapted in such a manner that an inverted image formed by the objective lens unit is inverted once again by the relay lens unit for forming an erect image, using at least one graded refractive index lens element in the relay lens unit, and having a small number of lens elements or a high magnification and favorably corrected aberrations.

Abstract: A fused glass block having an axial gradient index of refraction profile between two opposed parallel surfaces, with a change in refractive index from one of the surfaces to the other ranging from about 0.04 to 0.47, is provided. The fused glass block has a change in thermal expansion coefficient from one of the surfaces to the other of less than about 3.times.10.sup.-7 .degree.C..sup.-1, has essentially no strain or birefringence therein, and has a smoothly varying refractive index profile from one of the surfaces to the other. The fused glass block is prepared from at least two pre-selected compositions of a lead-silicate glass series that has been discovered to provide the requisite properties.

Abstract: Radial gradient index of refraction (GRIN) optical relays for overcorrecting axial chromatic aberration and a method for their manufacture are described. A relay including a radial GRIN rod in combination with a holographic optical element, or simple homogeneous or GRIN lenses, is described for adjusting axial chromatic and monochromatic aberrations, including spherical, coma, astigmatism, and distortion. The invention also describes remote viewing scopes, such as endoscopes and borescopes, which utilize said relays for achromatic, and reduced or corrected monochromatic aberration imaging. The use of segmented said relays provides a slight degree of flexibility in certain remote viewing scopes. A method for producing an exemplary negative dispersion GRIN lens is disclosed.

Abstract: A gradient index silicate glass is disclosed, which comprises a silicate glass and, incorporated therein, barium, at least one first metal selected from the group consisting of lead, titanium, niobium and tantalum and at least one second metal selected from the group consisting of potassium and sodium. The barium and the first and second metals have either protrudent and recessed concentration distribution profiles, respectively, or recessed and protrudent concentration distribution profiles, respectively. The gradient index silicate glass has a dispersion distribution of A DIRECTION permitting a highly effective optical design, and can be stably produced at low cost on a large commercial scale.

Abstract: An optical device comprises a single lens of a meniscus-type lens whose index of refraction is distributed in a radial direction perpendicular to the optical axis thereof, and a diaphragm having an aperture and provided at the concave side of the meniscus-type lens, wherein the optical device satisfies following formulas,7.ltoreq.F.ltoreq.1620.degree..ltoreq.2.omega..ltoreq.90.degree. .

Abstract: A multifocal ophthalmic lens has a spiral-like pattern on its surface in an area overlying the cornea of a wearer of the lens. The spiral-like pattern is capable of providing a plurality of different dioptric powers.

Abstract: A distributed refractive index type optical transmission plastic article has a circular cross section of a radius r.sub.0 which is in a range of 0.4 to 0.6 mm. A refractive index distribution of the optical transmission article substantially approximates a predetermined ideal refractive index distribution curve at least in a range of 0.25r.sub.0 to 0.70r.sub.0 extending from a center axis toward a peripheral surface of the article. A refractive index n.sub.0 at a central part of the article is in a range of 1.4 to 1.6. The article has a refractive index distribution constant of larger than 0.15 mm.sup.-1 and smaller than 0.3 mm.sup.-1, and a modulation transfer function of at least 55%. This optical transmission article is made from uncured liquid substances each having a viscosity of between 10.sup.3 and 10.sup.8 poises. N (N.gtoreq.2) uncured liquid substances having refractive indexes n of n.sub.1 >n.sub.2 >n.sub.3 . . . n.sub.

Abstract: An endoscope including a disposable probe and a non-disposable focusing ocular. The probe comprises negative and positive gradient index of refraction objective elements and a transfer module.

Abstract: Radial gradient index of refraction (GRIN) optical relays are described for overcorrecting axial chromatic aberration. In particular, a relay including a negative dispersion radial GRIN rod alone or in combination with simple homogeneous or GRIN lenses is described for adjusting axial chromatic and monochromatic aberrations, including spherical, coma, astigmatism, and distortion. The invention also describes remote viewing scopes, such as endoscopes and borescopes, which utilize GRIN relays for achromatic, and reduced or corrected monochromatic aberration imaging The use of segmented GRIN relays provides a degree of flexibility in remote viewing scopes.

Abstract: An objective lens system for endoscopes comprising, in order from the object side, a front lens unit having a negative refractive power, an aperture stop and a rear lens unit having a positive refractive power. This objective lens system is compact, comprises a small number of lens elements and favorably corrected aberrations, especially chromatic aberration, owing to a fact that at least one graded refractive index lens component is used in the front lens unit or the rear lens unit.

Abstract: A gradient index optical element has at least one first metal dopant selected from the group consisting of La, Y, Ga, In, Ge, Sn, Zn, Zr, Ba, Ca, As, Sr, Gd and Be distributed at a concentration gradient in a glass medium. The concentration gradient of the first metal dopant defines a slope having a direction. At least one second metal dopant different from the first metal dopant and selected from the group consisting of Bi, Sb, Nb, Ti, Ta, Pb, Tl, Zr, In, Sn, Y, Ba, Ca and Sr is distributed at a concentration gradient in the glass medium. The concentration gradient of the second metal dopant defines a slope smaller than the slope of the concentration gradient of the first metal dopant. The slope of the concentration gradient of the second metal dopant is in the same direction as the slope of the concentration gradient of the first metal dopant.

Abstract: A zoom lens having four groups and wherein at least one of the four groups is equipped with an index distribution type lens. A first lens group has a positive refracting power; a second group has a negative refracting power; a third lens group has a positive refracting power; and a fourth lens group has a positive refracting power. The first through fourth lens groups are arranged in this order from the object side, and the second group is moved to perform zooming while the fourth lens group is moved to compensate for image plane fluctuation which is incident to the zooming and also to perform focusing.

Abstract: A projection lens apparatus for a rear projection television. The projection lens apparatus includes a first lens in which the negative power of the lens gradually increases from the central portion of the lens, having almost no power, to the peripheral portion, a second lens having a strong positive power, a third lens in which the positive power of the lens gradually increases from the central portion, having almost no power, to the peripheral portion, a fourth lens having a positive power at the central portion and a negative power at the peripheral portion and a fifth lens having a strong negative power, wherein the first to fifth lenses are sequentially arranged along an optical axis toward a cathode ray tube from a screen. The various lenses perform different functions. Accordingly, the projection distance and the size of the lens are reduced, thereby reducing the size of the system.

Abstract: An optical system comprising a plural number of lens elements at least one of which is designed as a graded refractive index lens element having refractive index distribution in the radial direction, and has aberrations favorably corrected in said optical system as a whole by making most of the correcting functions of the graded refractive index lens element for Petzval's sum and chromatic aberration.

Abstract: These are graded index type optical transmission mediums with a radius (r.sub.o) of 0.45.+-.0.1 mm; they are optical transmission mediums which indicate a distribution close to the optimum quadratic curve in which the refractive index distribution in the range of a radius of at least 0.2 r.sub.o .about.0.8 r.sub.o minimizes mode diffusion; the modulation transfer factor, which indicates the degree of resolution, is a high resolution at 60% or more; they are optical transmission mediums suitable for the transmission of images in copiers, facsimiles and image sensors; and this involves a method for manufacturing said optical transmission mediums by eliminating a fixed quantity of the periphery of the graded index type optical transmission medium preforms.

Abstract: A lens system comprising, in order from the object side, a first lens component having a positive refractive power, a second lens component having a negative refractive power and a thrid lens component having a positive refractive power; the first lens component or the third lens component being a radial type graded refractive index lens component. The lens system is composed of the lens component in a number as small as three and has favorable optical performance.

Abstract: An image-reading device comprises a lens unit array comprising an array of distributed refractive index plastic cylindrical lens elements and plastic plates, adhering the distributed refractive index plastic cylindrical lens elements therebetween, and a plastic case containing and holding the lens unit array. The difference in the thermal expansion coefficients of the plates of the lens unit array and the plastic case is 5.0.times.10.sup.-5 cm/cm/.degree. C. or below, or more preferably, 3.0.times.10.sup.-5 cm/cm/.degree. C. or below. The plastic case is formed by connecting, in a longitudinal arrangement, a plurality of case segments formed by an injection molding.

Abstract: A method of manufacturing a multimode optical transmission medium from a synthetic resin having the distribution of refractive index varying continuously in a fixed direction. In the method, the polymerization is caused to proceed utilizing the effect of diffusion or exclusion of a monomer in the gel formed at the polymerization initiating terminal. Therefore, this method is free from the defects of methods using conventional polymerization reactions, and has an extremely high productivity.