Eastman-kodak Company

David P Hamblen

James Lee Bello

Sang H Kim

Clyde P Glover

Sharma Ravi

David S Ross

Ronald M Gluck

A diffractive optical element, ('DOE'), and particularly a diffractive lens having annular zones about an optical axis and known as a Fresnel zone plate or kinoform lens, is athermalized so that its effective focal length ('EFL') does not shift substantially with temperature over a temperature range by, respectively, increasing and decreasing the zone widths with respect to widths which are optimized to focus at the EFL at room temperature. Half of the zones (alternate, adjacent zones) provide the correct EFL for the expanded condition of the lens at the hot end of the temperature range; the other half of the zones provide correct EFL for the contracted condition of the lens at the cold end of the temperature range. The exact spacings and zone widths are obtained, in the same manner as a diffractive lens is corrected for spherical and chromatic aberration, from the coefficients of the equation governing the phase shift through the lens as a function of radial distance from the optical axis, by averaging the aberration properties at the hot and cold ends of the range, the net effect of which is to dictate the spacing of alternate, successive zones which are slightly greater and less than the zone spacings optimized at room temperature, respectively.

Athermalized diffractive optical elements

Diffractive lenses having gradial zones (62, 70, 78, 90, 98, 106, 114) are formed by separately, sequentially spin casting and polymerizing successive radial zones of the lens to produce optical phase differences of 2.pi. between adjacent gradial zones. Diffractive lenses may be molded in plano-plano(60), plano-concave (68) and plano-convex (76) geometries and also may be combined with conventional plano-plano (84), convex-convex (92), plano-concave (100) and plano-convex (108) refractive lenses.

Gradial zone lens and method of fabrication

Diffractive lenses having gradial zones (62, 70, 78, 90, 98, 106, 114) are formed by separately, sequentially spin casting and polymerizing successive radial zones of the lens to produce optical phase differences of 2.pi. between adjacent gradial zones. Diffractive lenses may be molded in plano-plano (60), plano-concave (68) and planoconvex (76) geometries and also may be combined with conventional plano-plano (84), convex-convex (92), plano-concave (100) and plano-convex (108) refractive lenses.

A device for coupling a laser diode emission to an optical fiber is provided. The device utilizes two opposed mirrors to redirect the divergent light beam of the laser diode to within the smaller numerical aperture or angle of acceptance of the optical fiber. The two opposed mirrors can be, for example, concave elliptical mirrors, a convex spherical and a concave spherical mirror, or a planar mirror and a concave spherical mirror. Each mirror has an aperture therein to allow passage of the initial laser diode beam or the redirected beam to the optical fiber.

Catoptric coupling to an optical fiber

An apparatus for producing a plastic lens element having a gradient index of refraction is disclosed in which first and second monomer-containing compositions, each having a different index of refraction, are injected into a centrifugal mold. Precise control of the gradient index is achieved by varying the ratio of the two monomers over a predetermined number of steps during the filling process.

Apparatus for fabricating grin lens elements by spin molding

The present invention relates to an optical element and catadioptric optical systems using the optical element. The optical element has a spherical surface with a reflective layer formed on at least a portion of the surface, and is formed of a radiant energy transmitting material having a radial gradient index of refraction. The catadioptric optical systems include at least two optical elements at least one of which is refractive, and at least one of which has a gradient index therein. One optical system includes first and second optical elements disposed sequentially along a longitudinal axis of the system. The second optical element is the optical element with the gradient index. The first optical element is formed of a homogeneous light transmitting material and includes a spherical surface, and a reflective layer formed on a central portion of one of the spherical surface.

Graded index optical elements and catadioptric optical systems

The present invention relates to implants (intraocular lenses) for implantation in the human eyeball to replace the natural crystalline lens. In general, the implant includes a body which includes anterior and posterior surfaces, an axis, and a periphery. The body is formed of a transparent material having an index of refraction which varies with a predetermined profile from the axis to the periphery of the body. In a first embodiment, the body is formed of one element having a convex-convex shape and an index of refraction which decreases in the direction away from the axis of the body. For dual-focus capabilities, the body has an inner and an outer zone with separate gradient profiles and surface curvatures, or an inner zone which is offset from the axis and is the center of the gradient profile. The inner and outer zones provide focusing for nearby and distant objects respectively. In a second embodiment, the implant includes an achromatic doublet lens of first and second contacting elements formed of a transparent material. The transparent materials of the first and second elements have gradient indices of refraction which decrease in opposite directions from each other between the axis to the periphery of the lens. Haptics extend from the periphery of each implant for engagement with appropriate portions of the eyeball.

Intraocular gradient-index lenses used in eye implantation

Methods are disclosed for the manufacture of individual small lenses, which may have gradient indices of refraction. A pedestal is provided having a conduit therein and an end surface the perimeter of which may be circular or elliptical. The perimeter is defined by a sharp edge. The pedestal is supported with the end surface horizontal and facing downwards. The intersection of the conduit and the surface, also defined by a sharp edge, forms an orifice through which at least one of the liquid monomers for forming the lens is fed. Gradient index small lenses are formed by suspending a first monomer from the horizontal end surface of the pedestal and then, via the orifice, introducing the second monomer at a rate which equals the rate of inter-diffusion of the second monomer into the first monomer. Alternatively, both monomers are both fed, in mixed condition, through the orifice in continuously varying proportions. The monomer(s) are cured in the pendant condition. The gradient index small lenses so formed are aspherical and, in the case of an elliptical pedestal end surface, also anamorphic.

Method and apparatus for manufacturing aspherically shaped small lenses

A method and apparatus for producing a plastic lens element having a gradient index of refraction is disclosed in which first and second monomer-containing compositions, each having a different index of refraction, are injected into a centrifugal mold. Precise control of the gradient index is achieved by varying the ratio of the two monomers over a predetermined number of steps during the filling process.

Method for fabricating grin lens elements by spin molding

Apparatus for the manufacture of individual small lenses, which may have gradient indices of refraction. The apparatus includes a pedestal having a conduit therein and an end surface the perimeter of which may be circular or elliptical. The perimeter is defined by a sharp edge. The pedestal is supported with the end surface horizontal and facing downwards. The intersection of the conduit and the surface, also defined by a sharp edge, forms an orifice through which at least one of the liquid monomers for forming the lens is fed. Gradient index small lenses are formed by suspending a first monomer from the horizontal end surface of the pedestal and then, via the orifice, introducing the second monomer at a rate which equals the rate of inter-diffusion of the second monomer into the first monomer. Alternatively, both monomers are both fed, in mixed condition, through the orifice in continuously varying proportions. The monomer(s) are cured in the pendant condition. The gradient index small lenses so formed are aspherical and, in the case of an elliptical pedestal end surface, also anamorphic.

Apparatus for manufacturing aspherically shaped small lenses

Each individual light emitter of a LED linear array is imaged by a discrete step-index light guide and gradient index microlens device. The light guides consist of high refractive index cores, each surrounded by low refractive index matter. A multiplicity of light guides are deposited in channels formed in a host material, such as a silicon wafer. The host material between adjacent channels functions as an opaque separator to prevent cross-talk between adjacent light guides. Optically bonded to the LED array, the light guides conduct a large portion of the diffuse light emitted to a series of microlenses optically bonded to and in registration with the exit end of each light guide. The microlenses are constructed in a transparent substrate, with each microlens having a spherical or aspherical gradient index profile and short focal length.

Step-index light guide and gradient index microlens device for LED

A method for cleaning the surface of a silicon semiconductor device comprising the steps of: (a) exposing, for a first time, said device for a predetermined time period to an anhydrous cleaning gas mixture containing nitric oxide and hydrogen chloride together with an inert carrier gas; and (b) exposing, for a second time, said device for a predetermined second time period to a gaseous plasma formed of CF.sub.4, H.sub.2 and N.sub.2 at RF power.

Gaseous cleaning method for silicon devices

A device and a method are disclosed for determining ion activity in liquids by the use of electrodes, particularly comprising an electrode mounting frame and transport means for promoting ionic migration between electrodes in the frame. Preferably, such electrodes are ion-selective electrodes.

Method for determining ionic activity of components of liquid drops

Device for determining ionic activity of components of liquid drops

A centrifugal molding method is provided for making a plastic lens having a gradient index of refraction. A reusable silicone rubber mold is placed in a rotatable mold carrier and two copolymerizable monomer compositions containing monomers having different indices of refraction are combined in the mold to form a polymerization mixture which has an index of refraction varying radially outward from its axis of rotation. The first monomer composition is placed in the mold and, while the mold is rotating sufficiently to force the first monomer composition to the outside edge of the mold, a second monomer composition is introduced via hypodermic injection into the center of the mold. The speed of rotation is reduced and the two monomer compositions diffuse one into the other in a controllable manner. Ultraviolet exposure, either directly on the mold or variably through a photographic mask with varying density, modifies the diffusion by initiating polymerization and increasing the viscosity of the monomer compositions. Finally the monomer compositions in the mold are completely polymerized by heat curing in an oven.

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Rochester, NY, United States of America

David P Hamblen