Abstract: Disclosed is a projection optical system with a diffractive optical element, wherein the diffractive optical element is arranged so that a portion of or most of diffraction light not to be used for projection of an image is prevented from being incident inside an image projection range upon an image plane.

Abstract: An apodised refractive index grating is recorded in a photosensitive optical fiber by forming first and second component interference patterns with different pitches, that are recorded in the grating such as to result in apodisation. The component patterns are spatially in phase in a central region and move progressively out of phase towards the ends of the patterns. The patterns may be recorded sequentially or concurrently. The fiber may be stretched once or cylically.

Abstract: A lens optical system is provided with a cemented lens element formed by cementing two constituent lens elements made of different optical materials together, with a diffractive optical surface formed at the cementing interface between the two constituent lens elements. The two constituent lens elements have at their respective interfaces with air a radius of curvature different from the radius of curvature that they have at the cementing interface.

Abstract: The present invention provides a method for determining a condition of aging for an optical waveguide grating. In this method, the aged deterioration curve of the optical waveguide grating is set as a form of C·t−&agr;, where t represents time, and &agr; and C represent parameters. Then, the condition of the aging is determined based on the aged deterioration curve.

Abstract: Condensers having a mirror with a diffraction grating in projection lithography using extreme ultra-violet significantly enhances critical dimension control. The diffraction grating has the effect of smoothing the illumination at the camera's entrance pupil with minimum light loss. Modeling suggests that critical dimension control for 100 nm features can be improved from 3 nm to less than about 0.5 nm.

Abstract: Optical gratings having a range of possible Bragg wavelengths can be produced using a single phase mask by exposing the mask to a non-collimated spatially filtered beam of light. A spatial filter removes high spatial frequency components from the beam, and a focusing system directs the filtered beam to a phase mask. A rate at which the beam is focused and a spacing between the phase mask and a photo-sensitive waveguide are varied to produce gratings in the waveguide having a range of possible periods.

Abstract: A photolithography system that employs a condenser that includes a series of aspheric mirrors on one side of a small, incoherent source of radiation producing a series of beams is provided. Each aspheric mirror images the quasi point source into a curved line segment. A relatively small arc of the ring image is needed by the camera; all of the beams are so manipulated that they all fall onto this same arc needed by the camera. Also, all of the beams are aimed through the camera's virtual entrance pupil. The condenser includes a correcting mirror for reshaping a beam segment which improves the overall system efficiency. The condenser efficiently fills the larger radius ringfield created by today's advanced camera designs. The system further includes (i) means for adjusting the intensity profile at the camera's entrance pupil or (ii) means for partially shielding the illumination imaging onto the mask or wafer.

Abstract: A scanning optical system is provided with a semiconductor laser, a polygonal mirror, which deflects a beam emitted from the semiconductor laser, an f&thgr; lens for converging the beam deflected by the deflector onto a surface to be scanned, and a diffractive surface between the polygonal mirror and the surface to be scanned. The diffractive surface compensates for a lateral chromatic aberration caused by the f&thgr; lens. Further, the diffraction efficiency of the diffractive surface on an optical axis of the f&thgr; lens is smaller than that of a peripheral portion to cancel a power variation due to a variation of the light quantity transmitted through the scanning lens.

Abstract: Disclosed are a lens efficiently manufactured into an accurate shape at a low cost, a manufacturing method thereof, and an optical pickup using the lens. The lens includes a geometrical optics portion for converging light having been incident thereon from its light incoming plane, and two diffraction optics portions provided on the light incoming plane and a light outgoing plane of the geometrical optics portion, wherein the diffraction optics portions are made from a material different from that of the geometrical optics portion.

Abstract: Disclosed is a diffractive optical element which includes a diffractive grating pattern ion a base plate. The diffractive grating pattern includes a plurality of phase gratings arranged in parallel lines extending along a predetermined direction to cause diffraction of an incident beam. Each of the plurality of phase gratings has an asymmetrical phase pattern. There is a phase gap, &Dgr;P, representing a phase difference (in radians) between an end point and a beginning point of each phase pattern. The phase gap, &Dgr;P, is substantially equal for each of the plurality of phase gratings and satisfies the relationship. 0.7&pgr;<|&Dgr;P|<1.2&pgr;.

Abstract: Condenser system for use with a ringfield camera in projection lithography where the condenser includes a series of segments of a parent aspheric mirror having one foci at a quasi-point source of radiation and the other foci at the radius of a ringfield have all but one or all of their beams translated and rotated by sets of mirrors such that all of the beams pass through the real entrance pupil of a ringfield camera about one of the beams and fall onto the ringfield radius as a coincident image as an arc of the ringfield. The condenser has a set of correcting mirrors with one of the correcting mirrors of each set, or a mirror that is common to said sets of mirrors, from which the radiation emanates, is a concave mirror that is positioned to shape a beam segment having a chord angle of about 25 to 85 degrees into a second beam segment having a chord angle of about 0 to 60 degrees.

Abstract: An amplitude mask, and an apparatus and method for manufacturing a long period grating filter using the same, are provided. When a long period grating is manufactured by selectively passing laser light to an optical fiber, the amplitude mask periodically passes laser light to the optical fiber. The amplitude mask includes two masks having periodically alternating pass areas for passing the laser light and nonpass areas for preventing passing of the laser light, the two masks being continuously rotated in opposite directions. The period of the pass area thus continuously changes. In this mask, two masks each having a predetermined period are rotated in opposite directions, to thus provide an amplitude mask period depending on the angle of rotation. Thus, the period of the amplitude mask can be continuously changed.

Abstract: A scanning optical system is provided with a light source, a deflector, which deflects a beam emitted from said light source, and a scanning lens for converging the beam deflected by the deflector onto a surface to be scanned. The scanning lens has a positive power as a whole, and includes a diffraction lens structure that is formed on at least one surface of one of the lens element. The diffractive lens structure compensates a lateral chromatic aberration caused by the refraction lens elements. The diffraction lens structure satisfies the following condition (1); 0.3≦m/W≦4.0  (1) where, m is the number of periodic patterns of the diffraction lens structure struck by the incident light beam having the maximum scan angle W (unit: degrees).

Abstract: A wide angle imaging system for providing a wide angle field of view 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: In accordance with the invention, an electrically modifiable optical fiber grating device is made by providing a fiber including a grating and forming a plurality of electrically conductive elements along the grating. In response to an electrical signal, the conductive elements modify the grating. In a preferred embodiment, a fiber grating is provided with a plurality of heating elements spaced to selectively heat different portions of the grating. This chirps the spacing between elements of the grating and thereby increases the bandwidth of the device.

Abstract: A viewfinder optical system includes an image inverting optical unit for inverting an image formed by an objective optical unit, the image inverting optical unit inverting the image by using a reflecting action of light, and an eyepiece optical unit on which light from the image inverting optical unit is made incident, wherein the viewfinder optical system has a diffractive optical surface.

Abstract: A viewfinder optical system includes an objective optical system for forming an image of an object, and an eye-piece optical system for converting rays of light from the image into substantially parallel rays of light, wherein the objective optical system is provided with an optical element having a diffraction optical surface.

Abstract: The present invention provides a method for determining a condition of aging for an optical fiber grating. This method comprises a step of setting the aged deterioration curve of the optical fiber grating as a form proportional to t.sup.-n, where t represents time, and n represents a parameter dependent on temperature; and a step of determining the condition of the aging according to the aged deterioration curve.

Abstract: There is provided an eyepiece lens system for viewing an image formed by an objective lens system. The eyepiece lens system includes a first refraction lens having a positive power, a second refraction lens having a positive power and at least one diffraction lens having a phase grating structure. The first and second lenses are arranged on an eye side with respect to a plane on which the image is formed.

Abstract: A beam splitting element includes a transparent substrate and a diffractive grating formed on the substrate for dividing an incident beam into a plurality of diffracted beams. The diffractive grating has a plurality of identically formed belt-shaped phase patterns that are arranged in parallel lines at equal pitches. The phase pattern has a sectional shape in a plane perpendicular to the parallel lines that causes non-linear phase difference to the beam passing therethrough within one pitch. Further, the adjacent phase patterns are connected without phase gaps at the boundaries therebetween.

Abstract: A spectrally resolved monochromatic light is provided which generally comprises an incoherent small source lamp, a concave grating for spectrally resolving the wavelengths of the light to obtain a particular wavelength, and an optical fiber for collecting and transmitting the particular wavelength. The light source can also have more than one optical fiber output, each having a different monochromatic wavelength. An order sorting device, such as a filter or dichroic mirror can be used to filter out the shorter wavelength radiation resulting from higher grating orders.

Abstract: Condensers having a mirror with a diffraction grating in projection lithography using extreme ultra-violet significantly enhances critical dimension control. The diffraction grating has the effect of smoothing the illumination at the camera's entrance pupil with minimum light loss. Modeling suggests that critical dimension control for 100 nm features can be improved from 3 nm to less than about 0.5 nm.

Abstract: An optical viewfinder system comprising two optical elements, and a field stop or a reticle, to provide an image of a scene to a viewer, and further comprising a diffractive optical element to provide a clear, stationary image of the field stop or reticle to the viewer.

Abstract: A zoom lens system has, from the object side, a first lens unit having a negative optical power and including at least one diffractive optical surface and a second lens unit having a positive optical power and including at least one diffractive optical surface. A distance between the first and second lens units varies during zooming operation.

Abstract: A triplet lens system composed of a first positive lens element, a second negative lens element and a third positive lens element. At least one lens surface is provided with a blazed zonal structure having a function of a positive diffractive lens.

Abstract: A scanning optical apparatus includes a semiconductor laser as a light source, a deflector for deflecting a light beam emitted from the semiconductor laser, and optical element for directing the light beam emitted from the semiconductor laser to a surface to be scanned. The optical element includes a refracting porion and a diffracting portion, wherein changes in the focus in the main scanning direction, resulting from the environmental fluctuations, of the scanning optical apparatus are corrected by a characteristic of the optical element.

Abstract: A zoom lens of the retrofocus type includes, in order from a longer-distance conjugate point side to a shorter-distance conjugate point side, a front lens unit of negative refractive power, and a rear lens unit of positive refractive power, wherein a separation between the front lens unit and the rear lens unit varies according to variation of magnification, and at least one of the front lens unit and the rear lens unit is provided with a diffractive optical element.

Abstract: The invention relates to a high-performance zoom lens system which can use a diffractive surface therein for use with an image sensor having a number of pixels. The zoom lens system includes at least a first lens group G1 having positive power and a second lens group G2 having negative power between an object side of the system and an aperture stop S. The first lens group G1 includes at least one diffractive surface r.sub.1, and satisfies the following condition:0.001<f.sub.S /f.sub.DOE <0.025 (1)Here f.sub.S =.sqroot.f(f.sub.W .times.f.sub.T) wherein f.sub.W and f.sub.T are focal lengths of the zoom lens system at its wide-angle end and its telephoto end, respectively, and f.sub.DOE is a focal length of the diffractive surface r.sub.1.

Abstract: An optical system that can be used in an optical imaging system and displays good imaging performance with corrected chromatic aberration without increasing the number of lenses is provided by employing a lens surface with a diffractive effect. The optical system uses a lens with a concave incident surface and positive refractive power. A grating element surface 40 with positive refractive power is formed on at least one surface of the lens. The surface on which the grating element is formed is an aspherical surface with a radius of curvature that becomes bigger with increasing distance from the optical axis.

Abstract: A real image finder optical system, having a relay lens system, comprises a positive first lens group, a positive second lens group, and a positive third lens group, in this order from the object. The finder optical system is arranged to form an inverted primary image of an object by the positive first lens group, and to form an erected secondary image by the positive second lens group functioning as the relay lens system so that the erected secondary image can be viewed through the third lens group. Furthermore, the second lens group comprises a diffractive optical element having at least one diffractive surface having positive diffractive power.

Abstract: An optical pickup apparatus compatible with at least two types of optical recording media, using light beams having respective different wavelengths for recording and reading information, the optical pickup apparatus including two laser light sources to emit light beams having the different wavelengths, respectively, a holographic lens, including a holographic ring, to transmittal of the light beams emitted from the laser light sources in an inner region of the holographic ring, and diffracting a specific light beam among the light beams emitted from the laser light sources in an outer region relative to the inner region, an objective lens to focus the light beams passed through the holographic ring lens on the respective information recording surfaces of the two types of the optical recording media, optical elements to alter optical paths of the light beams reflected from the information recording surfaces of the optical recording media; and two photodetectors to individually detect optical information from

Abstract: A color image reading apparatus is provided wherein a color picture image is read out by a monolithic three line sensor through a reflection type one-dimensional blazed diffraction grating acting as a color separating means. The diffraction grating is concavely curved forward the line sensor, and a light beam, diverging after being focused by an image forming optical element having a predetermined refracting power only in a sub-scan cross section, is color-separated into three color light components by the diffraction grating and re-imaged on the surface of the three line sensors located at a predetermined position. As a result, the blur of .+-.1 order diffracted lights in a sub-scanning direction can be prevented which is due to the deviation of a reflective diffraction angle resulting from the difference in an incident angle of respective lights on the grating surface in the sub-scan cross section.

Abstract: Disclosed is a diffractive optical element which includes a diffractive grating pattern on a base plate. The diffractive grating pattern includes a plurality of phase gratings arranged in parallel lines extending along a predetermined direction to cause diffraction of an incident beam. Each of the plurality of phase gratings has an asymmetrical phase pattern. There is a phase gap, .DELTA.P, representing a phase difference (in radians) between an end point and a beginning point of each phase pattern. The phase gap, .DELTA.P, is substantially equal for each of the plurality of phase gratings and satisfies the relationship0.7.pi.<.vertline..DELTA.P.vertline.<1.2 .pi..

Abstract: A decorative optical display (20) utilizing a reflective diffraction grating (94) or a transmissive diffraction grating (304) and a plurality of polychromatic light sources (60) disposed around perimeter (106) of the reflective diffraction grating or perimeter (314) of the transmissive diffraction grating. The light sources are disposed so as to the illuminate the reflective or transmissive diffraction grating at an oblique angle (204) or (328), respectively. The oblique illumination of the reflective or transmissive diffraction grating prevents a viewer (200) from seeing undiffracted light rays (212) or (336) emanating from the light sources, which can detract from the appeal of the optical display pattern (250). The reflective or transmissive diffraction grating may be flat or curved and may be supported by a support member (90). Further, the reflective or transmissive diffraction grating may have either a single or multiple axes.

Abstract: An optical element comprises a lens made of a material for shutting off all or most of light in the infrared region, and an optical low-pass filter, wherein the lens and the optical low-pass filter are incorporated with each other.

Abstract: This specification discloses a zoom lens which has, in succession from the object side, a first lens unit of positive refractive power, a second lens unit having negative refractive power and movable during a focal length change, a third lens unit for correcting the changing of an image plane resulting from the movement of the second lens unit, and a fixed fourth lens unit having positive refractive power, and in which an aspherical surface of a predetermined shape for correcting well spherical aberration and distortion resulting from a focal length change is provided on a predetermined lens surface in the first lens unit.

Abstract: Coma of an objective lens occurs depending on the lens-forming condition when plural disks of different substrate thickness are recorded and reproduced. An objective lens according to this invention is not influenced by the coma even if the thickness of the substrates is changed. For this purpose, a diffraction grating whose aberration is corrected is formed on the first side of an aspheric objective lens. Due to this correction, light beams having different diffraction orders, e.g. 0th order diffracted light and +1st order diffracted light, are focused respectively on two kinds of substrates of different thickness. The whole objective lens is tilted to correct its axial coma, and the tilt angle is predetermined to be substantially identical with respect to plural substrates which are different in thickness.

Abstract: The invention provides a compact yet high-zoom-ratio zoom lens system for use with lens shutter cameras, which is well corrected for aberrations albeit being made up of a small number of lenses. The zoom lens comprises a first lens group G1 of positive refracting power, a second lens group G2 of positive refractive power and a third lens group G3 of negative refracting power. The lens groups move for zooming from the wide angle side to the telephoto side, with a separation between the first and second lens groups becoming wide and a separation between the second and third lens groups becoming narrow. At least one lens group has a diffractive surface therein, and satisfies 1.8<.beta..sub.T /.beta..sub.W <4.0 where .beta..sub.T and .beta..sub.W are transverse magnifications of the lens group having a diffractive surface at the wide-angle end and the telephoto end of the lens system.

Abstract: The invention provides a high-performance yet low-cost phototaking optical system using a diffractive optical element. The optical system comprises, in order from an object side thereof, a first positive lens in a meniscus form convex toward the object side, an aperture stop, and a second positive lens in a double-convex form, with a diffractive surface formed on the object side of the first lens. The system comprising an aperture stop, at least two lenses and at least one diffractive surface satisfies the condition 0<d.sub.DOE /f<0.24 where f is a focal length of the overall system and d.sub.DOE is a distance on an optical axis thereof from the aperture stop to the diffractive surface. This condition is provided to locate the diffractive surface in the vicinity of the aperture stop to lower ray height, thereby placing chromatic aberration in a well-balanced state.

Abstract: The method for designing a diffractive lens to be formed on a refractive lens is disclosed. According to the method, a function of the diffractive lens is expressed as a polynomial optical path difference function using a height from an optical axis as a variable, a boundary of each zone to be formed is determined based on the optical path difference function, an angle of incidence of a ray on a macroscopic shape of the diffractive lens is determined, a shift, in a direction along the optical axis, corresponding to a unit wavelength of the optical path difference for each zone is determined based on the angle of incidence, an optical path difference to be given by each zone is determined based on the optical path difference function, and then a microscopic shape of each zone is determined.

Abstract: A zoom lens includes, in order from an object side, a first lens unit of positive refractive power, a second lens unit of negative refractive power, and a subsequent lens unit of positive refractive power as a whole, wherein during zooming from a wide-angle end to a telephoto end, at least the first lens unit is moved along an optical axis such that a separation between the first lens unit and the second lens unit increases, and wherein at least one diffractive optical element is provided in the first lens unit.

Abstract: A single lens of high performance and high image quality has a diffractive optical element and, more particularly, an optical system best suited for use on optical instruments for which chromatic aberrations must be corrected, e.g., silver halide or electronic cameras. The optical system has one positive lens and a stop. At least one surface of the positive lens is constructed of a diffractive surface r.sub.1, and satisfies the condition 3<f.sub.D /f<30 where f.sub.D is a focal length of the diffractive surface, and f is a focal length of the entire lens system.

Abstract: An optical arrangement including a stop, and an optical element with a diffractive optical surface, wherein the diffractive optical surface is defined on a spherical surface of a curvature radius r, and wherein, where the distance from a point on the diffractive optical surface, which is on an optical axis, to a center of the stop as viewed from the diffractive optical surface is t, a relation 0.8.ltoreq.r/t.ltoreq.1.2 is satisfied.

Abstract: A chromatic aberration correcting element that is a simple lens having at least one aspheric surface, the radius of curvature of which increases from the optical axis toward the periphery. At least one of the surfaces is formed as a diffraction lens surface that consists of annular segments that shift discretely in a direction in which the lens thickness increases as a function of the distance from the optical axis. Also disclosed is a chromatic aberration correcting device having annular segments formed in steps on either a light entrance face or a light exit face or both. The annular segments are composed of planes perpendicular to and concentric with the optical axis.

Abstract: A compound objective lens is composed of a hologram lens or transmitting a part of incident light without any diffraction to form a beam of transmitted light and diffracting a remaining part of the incident light to form a beam of first-order diffracted light, and an objective lens for converging the transmitted light to form a first converging spot on a front surface of a thin type of first information medium and converging the diffracted light to form a second converging spot on a front surface of a thick type of second information medium. Because the hologram selectively functions as a concave lens for the diffracted light, a curvature of the transmitted light differs from that of the diffracted light.

Abstract: A smooth contoured structure is formed from a planar surface by etching mesas of equal height into the surface and heat treating the structure to mass transport material above the desired contour to fill in voids below the desired contour. In an alternate embodiment, an optical element is formed using a patterned layer of sacrificial material and thermally treating the sacrificial layer to form a precursor contour line. The line is then transformed onto a substrate and smoothed to form the optical element.

Abstract: White light is input to light diffracting means so composed as to have a structure including macro prisms combined with a lenticular structure and include diffraction gratings at a microscopic level. As the height (h(x)) of unit steps of said diffraction grating is modulated at every period of arranged pixels, the output diffracted light is decomposed into three primary colors, and guided with highly accurate matching to the three respective primary color pixels of a liquid crystal panel means. In the pitch modulation type diffraction grating of the prior art, it was basically impossible to avoid the defect that the converged positions of a red light ray and a blue light ray deviate about 30%.

Abstract: The invention provides an imaging spectrometer that provides a wide field-of-view camera and spectrometer for spectral imaging of a large two-dimensional area of the Earth's surface from an orbiting satellite or airplane. The wide field-of-view camera fore-optics includes spherical optical elements arranged monocentrically. The spectrometer includes an all-reflective coupling design that transfers the curved optical image to one or more compact imaging spectrometers. The spectrometers preferably comprise a spherical convex holographic grating and associated reflective optics for dispersing a collimated optical beam into its spectral components and focusing the spectral image onto a planar detector array. The instrument described herein is designed to operate in a "pushbroom" fashion, that is, the forward motion of the satellite or airplane generates the spatial dimension of the resulting image.

Abstract: 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.

Abstract: An optical system for use in a relatively wide wavelength range including a plurality of diffractive optical elements whose diffraction efficiencies are optimized for different wavelengths within said predetermined wavelength range. A diffractive optical element for use in a wide wavelength range includes a light transmissive substrate having a plurality of surface regions and a plurality of surface relief diffractive gratings are formed in said surface regions such that diffraction efficiencies of these gratings are optimized for different wavelengths within said predetermined wavelength range. A diffractive optical element is formed by a single optical element having a light transmissive substrate which reveals a given spectral transmittance and a surface relief diffractive grating formed in a surface of said substrate such that a wavelength dependency of said grating provides a desired spectral transmittance together with said spectral transmittance of the substrate.