Abstract: In one embodiment of the invention, a grating structure etched on a mirror substrate has a grating period causing diffracting, out of an optical path, a first incident radiation within a first band around a first wavelength. A multi-layer coating deposited on the grating structure reflects the first incident radiation, in the optical path, within the first band and a second incident radiation within a second band around a second wavelength. In another embodiment, a first multi-layer coating deposited on a mirror substrate reflects a first incident radiation within a first band around a first wavelength and a second incident radiation, in an optical path, within a second band around a second wavelength. A grating structure is deposited on the first multi-layer coating. The grating structure is etched to have a grating period causing diffracting, out of the optical path, the second incident radiation within the second band.

Abstract: A renewable liquid reflecting zone plate. Electrodes are operatively connected to a dielectric liquid in a circular or other arrangement to produce a reflecting zone plate. A system for renewing the liquid uses a penetrable substrate.

Abstract: A diffractive optical element includes a diffraction optical part provided with a phase-type diffraction grating. The diffraction grating of the diffraction optical part has on the surface thereof minute uneven structure of which the period is substantially constant. The period is smaller than a wavelength used.

Abstract: An observation system having a positive refracting power as a whole comprises a first unit G1 with a positive refracting power and a second unit G2 and forms an exit pupil for observation of an electronic image displayed on an image display element 5. The first unit G1 comprises a prism 4 with a positive refracting power and a transmission-type volume hologram 6 and has an action of imaging an observation image for obtaining a relay image. The second unit G2 is composed of a reflection-type volume hologram 3 and has an action of forming the exit pupil 1 so as to introduce the relay image to an observer. At least one of reflecting surfaces and an exit surface of the prism 4 is shaped as a rotationally asymmetric surface which exerts a power on bundles of rays, to compensate aberrations generated by decentering.

Abstract: An optical pickup apparatus for first and second optical information recording medium, comprises first and second light sources to emit first and second light flux; a single objective lens made and a diaphragm having an aperture. The pitch of a plurality of ring-shaped diffractive zones provided on the objective lens, becomes gradually small from the optical axis to a point h and the pitch increases at the point h. At the time of conducting recording or reproducing information of the second optical information recording medium, the second light flux has a spherical aberration discontinuous portion at the point h where a spherical aberration-stepped amount is 7 &mgr;m to 40 &mgr;m, and a spherical aberration of a light ray of the second light flux having passed through the outermost portion of the aperture of the diaphragm is 7 &mgr;m to 40 &mgr;m.

Abstract: A diffraction optical element is configured such that a plurality of annular zones having minute steps extending in a direction of the optical axis therebetween are formed on a base element. The plurality of annular zones include narrow and wide zones respectively satisfying conditions (1) and (2): &Dgr;Z(i)<(1/2)·&Dgr;E(i)  (1), and &Dgr;Z(i)>(3/2)·&Dgr;E(i)  (2), wherein, i represents the order of the steps counted from the optical axis, &Dgr;E(i) represents an absolute value of an OPD provided by the i-th step, and &Dgr;Z(i) represents an absolute value of a difference between OPDs provided, with respect to a base curve, by an inner side end portion and outer side end portion of an annular zone between an i-th step and (i+1)-th step.

Abstract: Microsystems or micro-biotechnical components (1) are aligned, assembled, and dispensed onto a substrate (2). An image of a microsystem receiving region of the substrate is focused along hollow cones onto an image plane (23). The microsystem (1) is positioned within the hollow cones such that the image passes around it unaffected. A semi-transparent plate (24) permits the substrate image to pass therethrough and reflects an image of a surface of the microsystem which is facing the substrate to be reflected and pass along the same hollow conical paths to the image plane. In this manner, the images of the substrate and the micro component are superimposed. A mechanical device (11) adjusts the position of the microsystem until the images of the facing surfaces of the microsystem and the substrate are brought into preselected alignment.

Abstract: A wide angle imaging system for providing a wide angle field of view of an area exteriorly of a vehicle comprises an outer negative or wide angle group of lenses for receiving the wide angle field of view and directing a virtual image toward a positive, converging or focusing group of optics, which further refract and focus the image and provide a focused image to an image capture device. The focusing group of lenses preferably comprises three plastic optic elements, which include a diffractive element and aspheric surfaces to correct for color, distortion and other aberrations in the wide angle virtual image received from the wide angle group of lenses. The wide angle group of lenses are also preferably formed of a plastic material, such as polycarbonate or acrylic, and include a diffractive element on one of the elements. The imaging system thus provides a low cost, light weight and compact wide angle focusing system which does not include expensive and fragile precision optic and/or glass elements.

Abstract: By proposing a diffractive optical element having optical functions of a random phase plate and a lens array in combination, and an illumination apparatus employing this lens element, reduction of speckles, and improvements in energy efficiency and light utilization efficiency are achieved simultaneously.

Abstract: Provided in the present invention are an image pickup lens and a design method thereof which can achieve miniaturization of the system and capable of remarkably improving the optical characteristic with a simple structure. By forming a second face on the image pickup surface side of a lens body into a Fresnel face and unifying a diffraction element with at least a first face on the object face side or the second face on the image pickup surface side of the lens body, it becomes possible to correct the Petzval sum and reduce the curvature of the field so that an excellent image plane can be obtained. Also, due to the color dispersion characteristic of the diffraction element, chromatic aberration can be well corrected. Thereby, the optical characteristic of the image pickup lens can be remarkably improved.

Abstract: An objective lens for use in an optical pickup apparatus has a diffractive optical surface. A first light flux having a first wavelength of &lgr;1 is converged as a first number diffraction order diffracted-ray other than the zero-th order diffracted-ray onto an information recording plane of the first optical information recording medium having a thinner protective substrate t1 by the diffractive optical surface and a second light flux having a second wavelength of &lgr;2 (&lgr;1<&lgr;2) is converged as a second number diffraction order diffracted-ray other than the zero-th order diffracted-ray onto the information recording plane of the second optical information recording medium having a thicker protective substrate t2 (t1<t2) by the diffractive optical surface. The second number diffraction order is different from the first number diffraction order.

Abstract: In one embodiment of the invention, a grating structure etched on a mirror substrate has a grating period causing diffracting, out of an optical path, a first incident radiation within a first band around a first wavelength. A multi-layer coating deposited on the grating structure reflects the first incident radiation, in the optical path, within the first band and a second incident radiation within a second band around a second wavelength. In another embodiment, a first multi-layer coating deposited on a mirror substrate reflects a first incident radiation within a first band around a first wavelength and a second incident radiation, in an optical path, within a second band around a second wavelength. A grating structure is deposited on the first multi-layer coating. The grating structure is etched to have a grating period causing diffracting, out of the optical path, the second incident radiation within the second band.

Abstract: In the design of a lens system, lens parameters are determined by minimizing a merit function which is a sum of squares of ray aberrations or wavefront errors at many sampling points. Prior methods often select the parameters which give very narrow tolerances to production errors. The small tolerance increases the difficulty of production. In order to increase the tolerances, states which allot errors ±&dgr; to some chosen parameters are considered. Merit functions corresponding the error-allotted states are made. An integrated merit function is produced by adding the error-allotted merit functions to the non-error allotted normal merit function. Parameters are determined by minimizing the integrated merit function. The optimized parameters will give wider tolerances for the error-allotted parameters. DOE (diffraction optical elements) design includes the steps of considering error-allotted states S1, S2, . . . in addition to a non-error state S0, making merit functions E1, E2, . . . for S1, S2, . . .

Abstract: An aberration compensating optical element includes: a diffractive structure having a plurality of ring-shaped zone steps formed into substantially concentric circles on at least one surface of the aberration compensating optical element; wherein the aberration compensating optical element is adapted for being disposed on an optical path between a light source for emitting a light having a wavelength of not more than 550 nm, and an objective lens made of a material having an Abbe constant of not more than 95.

Abstract: In a holographic pattern provided in a holographic optical element, a pattern 1a twists a diffracted light beam in a clockwise direction, to form a semi-circular light spot Sa on photodetection parts A and B so as to extend over a dividing line LX in a four-segment photodetection part. A pattern 1b similarly twists the diffracted light beam in a clockwise direction, to form a semi-circular light spot Sb on photodetection parts C and D so as to extend over a dividing line LX in the four-segment photodetection part.

Abstract: One surface of the substrate constituting a diffraction type lens is formed with a zone plate exhibiting a smaller converging action with respect to a first wavelength &lgr;1 of light and a greater converging action with respect to a second wavelength &lgr;2 of light, whereas the other surface is formed with a zone plate exhibiting a smaller converging action with respect to the second wavelength &lgr;2 of light and a greater converging action with respect to the first wavelength &lgr;1 of light. The substrate is transparent to the first and second wavelengths &lgr;1 and &lgr;2 of light. Each of the zone plates comprises concentric gratings having a stepped cross section.

Abstract: Disclosed is a refractive-diffractive hybrid lens that includes a refractive lens having at least one aspherical surface, and a diffractive lens structure having a plurality of concentric ring-shaped steps that are formed on at least one lens surface of the refractive lens. The refractive lens and the diffractive lens structure are designed such that a change of the spherical aberration due to a change of the refractive index becomes small. That is, the refractive lens is designed to correct a coma and to reduce the change of the spherical aberration due to the variation of the refractive index, and the diffractive lens structure is designed to correct the residual spherical aberration. The refractive lens is a single biconvex lens, and at least one surface is aspherical. The diffractive lens structure generates a negative spherical aberration to reduce the ratio of a change of the spherical aberration to a variation of the refractive index.

Abstract: A zoom lens includes three lens units which are a first unit having a negative refracting power, a second unit having a positive refracting power, and a third unit having a positive refracting power arranged in the stated order from the side of an original surface. Zooming is effected by changing an air space between the first unit and the second unit and an air space between the second unit and the third unit. The second unit has a diffractive optical element.

Abstract: A multifocal lens including annular zones wherein each annular zone is divided into at least two annular sub-zones. Preferably, no geometric or optical optical steps are present between annular zones or annular sub-zones. The refractive powers within the annular sub-zones are chosen such that the lens exhibits at least two diffractive powers and that at least one of those diffractive powers substantially coincides with the average refractive power of each annular zone.

Abstract: The present invention provides a diffraction optical element comprising a first optical member having a first diffraction grating, a second optical member having a second diffraction grating, wherein the first and second optical members are stacked so that the first and second diffraction gratings face each other inside the stacked members and so that a space is formed between the diffraction gratings, and a sealing member for hermetically sealing the space between the diffraction gratings.

Abstract: An optical system includes a diffractive optical element having a diffraction grating provided, on a lens surface having curvature, in a concentric-circles shape rotationally-symmetrical with respect to an optical axis. A sign of the curvature of the lens surface having the diffraction grating provided thereon is the same as a sign of a focal length, in a design wavelength, of a system composed of, in the optical system, a surface disposed nearest to an object side to a surface disposed immediately before the lens surface having the diffraction grating provided thereon, and is different from a sign of a distance from the optical axis to a position where a center ray of an off-axial light flux enters the lens surface having the diffraction grating provided thereon. Further, an apex of an imaginary cone formed by extending a non-effective surface of the diffraction grating is located adjacent to the center of curvature of the lens surface having the diffraction grating provided thereon.

Abstract: A diffractive optical element has a plurality of diffraction structures for a certain wavelength. These each have a width measured in the plane of the diffractive optical element and a height measured perpendicularly thereto. The widths and the heights of the diffraction structures vary over the area of the diffractive optical element. An optical arrangement comprising such a diffractive optical element has, in addition, a neutral filter. The efficiency of such a diffractive optical element and of such an arrangement can be optimized locally for usable light.

Abstract: A diffractive optical element, as well as an optical system incorporating the same, has a comparatively large minimum grating pitch and, hence, is easy to produce. The diffractive optical element has a diffraction grating surface and an aspherical surface formed on an identical substrate or on separate substrates. The pitch of the diffractive grating varies such that it progressively decreases radially outward from the center of the substrate and then kept constant towards the radially outer extremity of the substrate.

Abstract: Disclosed is an optical element including a substrate made of a monocrystal of a fluoride compound, and a fine structure formed on the substrate and made of a non-monocrystal of metal fluoride. Also disclosed are an optical system having such optical element, and an exposure apparatus having such optical system incorporated therein.

Abstract: An optical system includes a diffractive optical element having a diffraction grating provided, on a lens surface having a curvature, in a concentric-circles shape rotationally-symmetrical with respect to an optical axis. The sign of the curvature of the lens surface having the diffraction grating provided thereon is the same as the sign of a focal length, at a design wavelength, of a system composed of, in the optical system, a surface disposed nearest to an object side to a surface disposed immediately before the lens surface having the diffraction grating provided thereon, and is different from the sign of the distance from the optical axis to a position where the center ray of an off-axial light flux enters the lens surface having the diffraction grating provided thereon. Further, the apex of an imaginary cone formed by extending a non-effective surface of the diffraction grating is located adjacent to the center of curvature of the lens surface having the diffraction grating provided thereon.

Abstract: A multibeam optical system that employs a laser source emitting a laser beam, a diffractive beam-dividing element that diffracts the laser beam emitted from the laser source to be divided into a plurality of diffracted beams exiting at different diffraction angle, and a compensating optical system. compensating optical system, which is afocal and consists of a first group and a second group, arranged at the position where beams divided by a diffractive beam-dividing element are incident thereon. The compensating optical system has a characteristic such that the angular magnification thereof is inversely proportional to the wavelength of the incident beam. The angular difference among the diffracted beam caused by the wavelength dependence of the diffractive beam-dividing element can be reduced when the beams transmit the compensating optical system.

Abstract: A diffractive lens constructed in accordance with the invention comprises a set of bands such that the diffractive gratings in each band are modified. This is done to ensure that even if the lens is tilted (e.g. to prevent light from reflecting off the lens and, introducing distortion into an optical system), the lens continues to focus light onto a small point on a target surface. (The target surface is typically an optical or magneto-optic data recording medium.

Abstract: Optical systems employing stepped diffractive surfaces (13) are provided. Ray tracing through such systems is performed using the grating equation to represent the stepped diffractive surface (SDS). In this way, the SDS can be used to correct a variety of monochromatic and chromatic aberrations by balancing the aberrations of the SDS against the aberrations of non-stepped optical surfaces in the system.

Abstract: Provided is a light emitting device including a Fresnel lens and/or a holographic diffuser formed on a surface of a semiconductor light emitter for improved light extraction, and a method for forming such light emitting device. Also provided is a light emitting device including an optical element stamped on a surface for improved light extraction and the stamping method used to form such device. An optical element formed on the surface of a semiconductor light emitter reduces reflective loss and loss due to total internal reflection, thereby improving light extraction efficiency. A Fresnel lens or a holographic diffuser may be formed on a surface by wet chemical etching or dry etching techniques, such as plasma etching, reactive ion etching, and chemically-assisted ion beam etching, optionally in conjunction with a lithographic technique. In addition, a Fresnel lens or a holographic diffuser may be milled, scribed, or ablated into the surface.

Abstract: In a diffraction type optical pickup lens, at least one surface of a convergent lens is formed with such an aspheric surface that a luminous flux having a wavelength &lgr;1 is converged at a first predetermined position. At least one surface of the convergent lens is formed with a zone plate having such a wavelength selectivity that a luminous flux having a wavelength &lgr;2 is converged at a second predetermined position whereas the luminous flux having a wavelength &lgr;1 is transmitted therethrough as it is. The convergent lens is transparent to the luminous fluxes having the wavelengths &lgr;1 and &lgr;2.

Abstract: An optical system including a diffraction optical element and for forming an image of an object by light having a given wavelength width includes at least one diffraction optical element and a diffraction light selection element for transmitting a diffraction light of given order to an output side of the diffraction optical element and for attenuating the diffraction light of orders other than the given order.

Abstract: High-density polyethylene (HDPE) is used as a coating for optical elements operating in transmission in the infrared spectrum, which are made up of a material other than polyethylene, such as hygroscopic salt, semiconductor materials, fluorides, chalcogenides, silver halides, and others, so as to exploit the optical properties of HDPE, at the same time keeping the thickness reduced.

Abstract: A diffractive lens, comprises an optical axis; a lens surface having a peripheral portion, and a diffractive relief provided on the lens surface, wherein the diffractive relief is shaped in annular zones, and wherein following conditional formulas (1) and (2) are satisfied: hi−1≦h<hi  (1) x=f(h−hti)+S  (2) where i is a suffix showing an ordinal number of each of the diffractive annular zones obtained by counting each diffractive annular zone in such a manner that a diffractive annular zone including the optical axis is counted as a first diffractive annular zone and other diffractive annular zones are counted respectively in consecutive order from the optical axis toward the peripheral portion; h is a distance between a point and X axis in which, when the optical axis is deemed as X axis, the distance is from X axis to the point in a direction perpendicular to X axis; hi is a distance from X axis to a border between i-th diffractive annular zone and (i&plus

Abstract: A renewable liquid reflecting zone plate. Electrodes are operatively connected to a dielectric liquid in a circular or other arrangement to produce a reflecting zone plate. A system for renewing the liquid uses a penetrable substrate.

Abstract: A grating member comprising a diffraction grating having a periodic structure for converting an incident wavefront at the central area into a prescribed wavefront is provided with a light-shielding member comprising a UV-light absorbing material at the periphery of the grating member in order to reduce excess light and scattered light.

Abstract: A diffractive-refractive achromatic lens that has a positive resultant power includes a refractive lens system and a positive diffractive grating. The refractive lens system is provided with a positive lens having relatively small dispersion, a negative lens having relatively large dispersion and an additional refractive lens. The additional refractive lens is a positive lens. The refractive lens system exhibits longitudinal chromatic aberration that is substantially proportional to wavelength such that the back focus of the refractive lens system decreases as the wavelength becomes shorter. The positive diffractive grating corrects the longitudinal chromatic aberration of the refractive lens system. The condition 0.005<f/fD<0.2 is satisfied where f is the focal length of the entire lens system, and fD is the focal length of said positive diffractive grating.

Abstract: Disclosed is a diffractive optical element which is made of at least two materials of different dispersions and which includes at least two diffraction gratings being accumulated one upon another, wherein each diffraction grating is formed on a curved surface of a substrate, and wherein a diffraction grating, of the at least two diffraction gratings, in which a curvature radius of the curved surface and a curvature radius of a grating surface in a portion where a grating pitch is largest, have different signs, is one of the at least two diffraction gratings which has a smallest grating thickness.

Abstract: Optical systems employing stepped diffractive surfaces (13) are provided. Ray tracing through such systems is performed using the grating equation to represent the stepped diffractive surface (SDS). In this way, the SDS can be used to correct a variety of monochromatic and chromatic aberrations by balancing the aberrations of the SDS against the aberrations of non-stepped optical surfaces in the system.

Abstract: A beam reshaping device includes first and second beam converting units having beam converging powers different in two orthogonal directions. The first and second beam converting units are arranged such that conjugate points correspond to each other in the two orthogonal directions, thereby reshaping the sectional form of a laser beam emitted from a laser light source, while effectively preventing occurrence of astigmatism. The beam reshaping device may be applied to an optical head device and which in turn may be used in an optical disk system.

Abstract: A diffractive-refractive achromatic lens that has a positive resultant power includes a refractive lens system and a positive diffractive grating. The refractive lens system is provided with a positive lens having relatively small dispersion, a negative lens having relatively large dispersion and an additional refractive lens. The additional refractive lens is a positive lens. The refractive lens system exhibits longitudinal chromatic aberration that is substantially proportional to wavelength such that the back focus of the refractive lens system decreases as the wavelength becomes shorter. The positive diffractive grating corrects the longitudinal chromatic aberration of the refractive lens system. The condition 0.005<f/fD<0.2 is satisfied where f is the focal length of the entire lens system, and fD is the focal length of said positive diffractive grating.

Abstract: A thin and light optical device satisfactorily separates light components having different properties. A blazed grating is formed on a surface of a flat-plate-shaped transparent substrate, and a separation coating that reflects or transmits incident light according to the properties of the incident light is provided on the blazed grating. The thus obtained optical device offers a function of separating light into reflected light and transmitted light, and also has a function of diffracting or refracting the thus separated light. As the separation coating, a polarization separation film, dichroic film, angle separation film, or chiral nematic liquid crystal layer is used to separate linearly polarized light components having different polarization planes, light components having different wavelengths, light components incident at different angles of incidence, or circularly polarized light components having different rotation directions.

Abstract: A magneto optic or optical disk drive comprises a laser source for providing laser beam, and a lens or compound lens for focussing the laser onto a currently inserted recording disk with specific overcoat thickness. In one embodiment, the lens is a compound lens that can focus aberration-free spots on different types of disk media having recording layers located under overcoats of different thicknesses. When a specific disk is inserted, only one spot in focussed onto the current recording layer. Furthermore, if the disk spins rapidly, it can wobble. The lens or compound lens comprises different regions where the focal length may vary slightly and continuously or discretely. Because of this, as the disk wobbles, the lens can nonetheless continue to focus laser light onto a small spot on the recording media, providing increased depth of focus in the vicinity of the currently inserted recording media.

Abstract: A binary-type optical diffraction device having the excellent capability of antireflection includes a step structure by which lens elements of a Fresnel lens are approximated. The surface of the steps formed on a substrate is entirely covered with a thin film having a flat surface. The height of each step and the refractive index of the thin film are selected so that the antireflection conditions for the respective steps are satisfied and thus the intensity of the reflected light rays is minimized.

Abstract: The invention relates to a method of easily and quantitatively determining the diffraction efficiency of a relief type diffraction optical element, and provides a method of designing an optical system comprising a diffractive optical element using diffraction efficiency as at least one estimation index. The diffractive optical element is a transmission blaze grating constructed of a relief having a sawtooth shape in section. The transmission blaze grating having a side wall substantially vertical to a grating surface. The estimation index is given by a predetermined mathematical expression including at least a phase difference due to a relief discontinuity and shadow effects thereof. The mathematical expression includes as the shadow effects of said discontinuity at least a light attenuation effect dependent on an angle-of-incidence and a light attenuation effect independent on the angle-of-incidence in a separate manner.

Abstract: An optical element includes a first substrate having a diffractive surface or a surface structure with a surface level difference, a second substrate for covering the diffractive surface or the surface structure to provide a shield therefor, and a groove provided at the diffractive surface or the surface structure, and extending from a central portion to a peripheral portion thereof, for discharging or replacing a gas at the diffractive surface or the surface structure therethrough.

Abstract: An optical beam shaper for production of a uniform sheet of light for use in a parts inspection system having a light source including a coherent light generator, a diffractive beam shaper, and lens elements.

Abstract: An optical arrangement includes a diffractive optical element and a curvature control system for changing curvature of the diffractive optical element. The optical arrangement can be incorporated into an exposure apparatus having an illuminating system for illuminating a mask having a pattern formed thereon and a projecting system for projecting the pattern of the mask onto a wafer, such that the projecting system includes a diffractive optical element and a curvature control system for changing curvature of the diffractive optical element.

Abstract: An infrared lens and detector system and associated method are disclosed that utilize infrared lenses to form an internal entrance pupil at which an internal aperture stop is placed to control the intensity of infrared radiation focused on the infrared detector. In more detailed respects, the infrared lens is an assembly including a first infrared lens, a second infrared lens spaced from the first lens to form a pupil between the first and second lenses, and an aperture stop disposed proximal the pupil. The aperture stop may have a fixed diameter or may have an aperture stop that is manually or automatically adjustable depending upon the intensity of the infrared radiation being viewed. Significantly, this lens assembly may be sealed for improved performance particularly in extreme conditions. In more detailed respects, the lens assembly forms a wide-angle lens and includes a diffractive surface on the second lens to reduce color aberrations and improve performance.

Abstract: Method for the preparation of holographic diffusers where the holographic diffuser is designed through iterative calculations according to the Fraunhofer theory of diffraction and some constrain conditions. In the iterative calculation some constrain conditions that can change the magnitude of the light passing through the diffuser are used to design the diffuser. A novel iterative calculation is disclosed such that uniformed mixing of colors and high light utilization efficiency of the diffuser may be provided.

Abstract: A monolithic element has a substrate body and at least one macro-optical characteristic integral in a first portion of the optical element. A plurality of surface micro-structures are integral in a portion of the optical element. The micro-structures are designed to homogenize light passing through the optical element to produce a predetermined pattern of smoothly varying, non-discontinuous light exiting the optical element. The light exiting the optical element is therefore altered according to both the macro-optical characteristic of the optical element as well as the homogenizing characteristics of the micro-structures.