Abstract: A projection optical system projects an image of an object onto an image plane, and includes a first imaging optical system for forming an image of the object, and a second imaging optical system for re-imaging the image upon the image plane, wherein the first and second imaging optical systems are disposed in an order from the object side and are disposed along a common straight optical axis. The first imaging optical system includes a first mirror for reflecting and collecting abaxial light from the object, wherein one of the first and second imaging optical systems includes a second mirror for reflecting light from the first mirror to the image plane side, and wherein, with the second mirror, the abaxial light is caused to pass an outside of an effective diameter of the first mirror.

Abstract: A projection lens (10) for a microlithographic projection exposure apparatus has a first optical element, for example a birefringent lens (L2), that has polarization dependent properties causing intensity fluctuations in an image plane of the projection lens. These fluctuation may be produced by a second optical element (24), for example a polarization selective beam splitting layer (28), that is arranged downstream of the first optical element. A gray filter (32; 132; 232) disposed in the beam path reduces the intensity fluctuations.

Abstract: A projection lens system is comprised of five lens groups. A first lens group forms a negative power lens group, and a second lens group forms a positive power lens group. Third, fourth, and fifth lens groups, when combined, form a positive power lens group, which helps to compensate for aberrations. At least one of the component lenses moves to adjust the system's focus. An image display system that includes such a projection lens system can project digital optical images for projection and other image display applications.

Abstract: An improved coupler with contrast ribs for use in a projection system. The coupler supports a projection lens in alignment with a projection optical signal generation device (e.g., a Cathode Ray Tube). The contrast ribs minimize contrast distortion that occurs in the coupler. The coupler defines a cooling chamber between said projection lens and said projection signal generating device and is filled with liquid in order to transport the optical signal between the projection optical signal generation device and projection lens. The contrast ribs change the angle of reflection of stray light rays generated by the projection optical signal generation device and direct a portion of those stray light rays to other contrast ribs. The ribs are preferably coated with a chemical composition that helps allow the ribs to absorb a portion of each ray incident on the rib.

Abstract: A projection zoom lens includes, from an image side to an object side, a first lens group having a negative refractive power, consisting of a number of lens elements and being movable along the optical axis of the projection zoom lens; a second lens group having a positive refractive power, consisting of a number of lens elements and being movable along the optical axis of the projection zoom lens; and an aperture stop arranged between two lens elements of the second lens group and being axially movable therewith.

Abstract: It is proposed to provide in an illumination unit (10) a light combining section (15) being adapted for receiving and combining first and second primary illumination light (L11, L12) or a derivative thereof and a light collecting, integrating and redirecting section (20) being adapted for receiving, collecting, integrating and redirecting first and second primary illumination light (L11, L12) or a derivative thereof, wherein said light combining section (15) and said light collecting, integrating and redirecting section (20) are at least partly arranged in a spatially mingled manner with respect to each other. Thereby from said first and second primary illumination light (L11, L12) collected, integrated and redirected combined primary illumination light (CL1) can be obtained and emitted as secondary illumination light (L2) having controlled spectral properties and an essentially uniformized spatial intensity distribution.

Abstract: A projection lens unit compensates for thermal expansion and contraction. The unit comprises a coupler at the front surface of a CRT, a lens unit body for projecting an image onto a screen by controlling and magnifying the light from the CRT, a plurality of legs secured to the coupler for supporting the lens unit body at more than three points, a slide mechanism (latch arms and latch engaging slots provided between the legs and the lens unit body for slidably supporting the legs for movement along the optical axis relative to the lens unit body, and expansion/contraction bars provided between the legs and the lens unit body for compensating for the thermally induced expansion/contraction, with one end engaged with a leg and the other end engaged with the base of the lens unit body.

Abstract: Projection lens systems for use with cathode ray tube (CRT) projection televisions are provided which have positive first lens units (U1) and negative second lens units (U2) where the negative second lens units are customized in terms of at least one optical property for at least two of the colors of light produced by the CRTs with which the units are used. The at least one optical property is not spectral transmission, although the second lens units can also be customized for spectral transmission. As illustrated in FIGS. 1B–1F and FIGS. 8B–8F, such customization of a non-transmissive property provides an effective and cost effective approach for improving the color performance of CRT projection lens systems. Constructions for the positive first lens unit which improve image contrast and reduce manufacturing costs are also provided.

Abstract: Disclosed is a simple and compact optical element holding system in a projection optical system which enables correction of astigmatism without causing comatic aberration. The holding system includes a relative angle adjusting system for tilting one of at least two optical elements with respect to an optical axis, and a tilt angle adjusting system for tilting the at least two optical elements integrally, by the same amount as and in an opposite direction to the tilt direction of the relative angle adjusting system, with respect to the optical axis and separately from the relative angle adjusting system.

Abstract: A projection optical system includes from the enlargement side a first lens unit, a mirror which is an optical path bending member, a second lens unit, and a third lens unit. The projection optical system is designed so that a condition (1), 5.5<T12/FL<12.0, is fulfilled. Here, T12 is the air equivalent distance between the first lens unit and the second lens unit, and FL is the overall focal length of the projection optical system. By fulfilling the condition (1), it is unnecessary that the diameter of the first lens unit be extremely large. It is also unnecessary to change the lens shape to prevent interference between the first lens unit and the second lens units, so that an increase in the cost of the projection optical system can be suppressed.

Abstract: A projection lens, for enlarging and projecting a picture formed on a flat fluorescent plate of a CRT projection tube, includes: a first lens unit of a plus lens, having aspheric surfaces on both surfaces, being convex to the screen side at a central portion including an optical axis, a second lens unit of a minus lens, having aspheric surfaces on both surfaces, being concave to the screen side at a central portion including an optical axis; a third lens unit of a plus lens, having spherical surfaces on both surfaces, being convex on both sides; a fourth lens unit of a plus lens, having aspheric surfaces on both surfaces thereof, being curved in concave-like to the screen side, on a peripheral portion far from the optical axis into a radial direction; and a fifth lens unit of a minus lens, being made up with a transparent liquid, commonly serving a faceplate of the CRT projection tube and a cooling, and a meniscus lens, having a thickness being nearly equal to and at least an aspheric surface directing a conc

Abstract: An object is to obtain a projection optical system capable of projecting image information onto a screen while maintaining satisfactory optical performance, and projection apparatus using it. An image display element and the screen both are set normal to the reference optical axis of the projection optical system, and at least one optical element out of a plurality of optical elements constituting the projection optical system has an optical axis shifted from the reference optical axis or/and tilted relative to the reference optical axis.

Abstract: Projection lenses for use with pixelized panels (PP) are provided. The projection lenses have first and second lens units (U1,U2), with the first lens unit having a negative or weakly positive power and the second lens unit having a positive power. The second lens unit has first and second subunits (U2S1 and U2S2) which provide positive power followed by negative power. The second subunit (U2S2) of the second unit (U2), in turn, has negative power followed by positive power. In this way, an overall short projection lens (e.g., BRL/f0?0.9) along with small lens elements (e.g., CAmax/f0?0.8) can be achieved.

Abstract: A catadioptric projection lens configured for imaging a pattern arranged in an object plane (2) onto an image plane (4) while creating a single, real, intermediate image (3) has a catadioptric imaging group (5) having a concave mirror (6) and a beam-deflector (7), and a dioptric imaging lens group (20) that commences after the beam-deflector. The system is configured such that the intermediate image follows the first lens (17) of a dioptric section (8) and is preferably readily accessible. Arranging the intermediate image both between a pair of lenses (17, 21) of the dioptric section and at a large distance behind the final reflective surface of the beam-deflector helps to avoid imaging aberrations.

Abstract: Projection lenses for use with pixelized panels (PP) are provided. The projection lenses have first and second lens units (U1,U2), with the first lens unit having a negative power and the second lens unit having a positive power. The first lens unit has a first lens element (L1) having a generally meniscus shape and a second lens element (L2) having a biconcave shape when its surface configurations are described by best fit spherical surfaces. The second lens element (L2) has an Abbe number (vL2) which is (a) less than or equal to 55 and (b) less than the Abbe number (VL1) of the first lens element (L1). The second lens element (L2) also has an optical power (?L2/0.7CA) at 0.7 of the clear aperture of its short conjugate surface which is negative and has a magnitude which is greater than the second lens element's on-axis optical power (?L2). This combination of lens shapes, Abbe numbers, and optical powers provides higher order lateral color correction without the need for abnormal partial dispersion glasses.

Abstract: A projection exposure lens has an object plane, optical elements for separating beams, a concave mirror, an image plane, a first lens system arranged between the object plane and the optical elements for separating beams, a second double pass lens system arranged between the optical elements for separating beams and the concave mirror, a third lens system arranged between the optical elements for separating beams and the image plane. The second lens system has a maximum of five lenses.

Abstract: A projection optical system for projecting an image of an object onto an image plane. The projection optical system includes a first imaging optical system for forming an image of the object in which the first imaging optical system includes a first mirror for reflecting and collecting abaxial light from the object, a second imaging optical system for re-imaging the image upon the image plane, a second mirror for reflecting light from the first mirror to the image plane side, whereby the abaxial light is caused to pass outside of an effective diameter of the first mirror, and a field optical system including three lenses each having a positive refractive power. The abaxial light passed through the outside of the effective diameter of the first mirror is refracted by the three lenses toward a direction nearing an optical axis of the three lenses.

Abstract: Objective (1, 601), in particular a projection objective for a microlithography projection apparatus, with first birefringent lenses (L108, L109, L129, L130) and with second birefringent lenses (L101–L107, L110–L128). The first lenses (L108, L109, L129, L130) are distinguished from the second lenses (L101–L107, L110–L128) by the lens material used or by the material orientation. After passing through the first lenses (L108, L109, L129, L130) and the second lenses (L101–L107, L110–L128), an outer aperture ray (5, 7) and a principal ray (9) are subject to optical path differences for two mutually orthogonal states of polarization. The difference between these optical path differences is smaller than 25% of the working wavelength. In at least one first lens (L129, L130), the aperture angle of the outer aperture ray (5, 7) is at least 70% of the largest aperture angle occurring for said aperture ray in all of the first lenses (L108, L109, L129, L130) and second lenses (L101–L107, L110–L128).

Abstract: A zoom lens includes, in order from the enlarging side: a first lens group that has negative refractive power, is movable for focusing, and is stationary during zooming; second, third, and fourth lens groups that are movable for zooming; and a fifth lens group that is stationary during zooming. The second and fifth lens groups have positive refractive power and the third and fourth lens groups have negative refractive power. The second and third lens groups move nearer the enlarging side when the zoom lens zooms toward the telephoto end and the fourth lens group is positioned nearer the reducing side when at the telephoto end than when at the wide-angle end. The ratios of the focal lengths of the first, second, fourth, and fifth lens groups to the focal length of the zoom lens satisfy four conditions. A projection display device uses the zoom lens.

Abstract: The optical system disclosed in this specification is a variable power optical system for enlarging and projecting a reduction side object onto an enlargement side image plane, or reducing and projecting an enlargement side object onto a reduction side image plane. This variable power optical system includes a first optical component having a reflecting curved surface, and a second optical component disposed more toward the reduction side than the first optical component. The second optical component has a plurality of movable lens units, and the variable power optical system effects a variable power operation by movement of the plurality of lens units. If ray was traced from the reduction side toward the enlargement side, the second optical component forms an image of a reduction side conjugate point on the enlargement side than an optical surface of the first optical component that is most adjacent to the reduction side.

Abstract: A six-element cinema projection lens is described in front of which an aspherized plane-parallel plate is positioned on the screen side. This arrangement permits the cost-effective design of a cinema projection lens with a relative aperture of 1:1.7 having very good image-forming properties. The high relative aperture increases the light utilization and therefore leads to savings in energy and costs. Furthermore, the projection lens can be used both for cinemascope format and for widescreen format, the differences in brightness being compensated by a variable diaphragm.

Abstract: A projection system for projecting a pattern of a mask onto a substrate. The projection system includes a projection optical system disposed between the mask and the substrate, and an optical element for correcting aberration produced in the projection optical system. The optical element has different refracting powers in two orthogonal directions or has a refracting power in one direction of two orthogonal directions and no refracting power in the other of the two orthogonal directions. The optical element is disposed between the mask and the substrate. An optical axis of the optical element is inclined with respect to an optical axis of the projection optical system.

Abstract: A liquid immersion photolithography system includes an exposure system that exposes a substrate with electromagnetic radiation, and also includes a projection optical system that focuses the electromagnetic radiation on the substrate. A liquid supply system provides a liquid between the projection optical system and the substrate. The projection optical system is positioned below the substrate.

Abstract: A spatial light modulator has pixel sections for performing spatial light modulation of light. An image-side telecentric image forming optical system forms an image of a two-dimensional pattern of the light having been obtained from the spatial light modulation. A microlens array having microlenses arrayed in two-dimensional directions is located in the vicinity of a plane of image formation of the two-dimensional pattern, whose image is formed by the image forming optical system. A magnification adjusting optical system for adjusting a magnification of image formation at the time of the formation of the image of the two-dimensional pattern of the light with the image forming optical system is located between the image forming optical system and the microlens array.

Abstract: A projection type image display apparatus having an image display element outputting an image ray, a projection lens apparatus for performing overhead projection of the image ray from the image display element, the projection lens apparatus having a plurality of lens elements, a reflection mirror reflecting the image ray from the projection lens apparatus, and a screen on which the image ray reflected by the reflection mirror is projected. An optical axis of the projection lens apparatus is decentered from a center of the screen.

Abstract: A projection aligner of the present invention, in which ultraviolet light emitted from a lamp housing is split by a fly-eye lens into a large number of point light sources which are independent of one another. Further, in this projection aligner, the light is shaped by an aperture, so that a secondary light source plane is formed. Moreover, after an exposure area is established by a blind, a photomask is illuminated. Thereafter, an image of a light source is formed on a pupillary surface of a projection optical system from light diffracted by the photomask. Furthermore, a wave front aberration is compensated by an aberration eliminating filter placed on the pupillary surface of the optical system of the projection aligner. Then, the image of a circuit pattern is formed on a wafer. Thereby, the influence of the aberration of the optical system is eliminated. Consequently, the high-accuracy transferring of the pattern can be achieved.

Abstract: Improvements in the fabrication of integrated circuits are driven by the decrease of the size of the features printed on the wafers. Current lithography techniques limits have been extended through the use of phase-shifting masks, off-axis illumination, and proximity effect correction. More recently, liquid immersion lithography has been proposed as a way to extend even further the limits of optical lithography. This invention described a methodology based on contact printing using a projection lens to define the image of the mask onto the wafer. As the imaging is performed in a solid material, larger refractive indices can be obtained and the resolution of the imaging system can be increased.

Abstract: An optical system includes multiple cubic crystalline optical elements and one or more uniaxial birefringent elements in which the crystal lattices of the cubic crystalline optical elements are oriented with respect to each other to reduce the effects of intrinsic birefringence and produce a system with reduced retardance. The net retardance of the system is reduced by the cancellation of retardance contributions from the multiple cubic crystalline optical elements and the uniaxial birefringent element. The optical system may be used in a photolithography tool to pattern substrates such as semiconductor substrates and thereby produce semiconductor devices.

Abstract: A luminous flux, from one conjugate surface (A), having an opening angle of at least 10° sequentially passes through a first optical system (30) having a luminous flux convergent action in the vicinity of its reference axis and a second optical system (31) having a luminous flux divergent action in the vicinity of its reference axis, and converges on another conjugate surface (B). A specific condition is given to the converging distance of each converging point at a luminous flux section including a principal ray according to the passing position of the luminous flux through the first optical system (30) to thereby implement an oblique-incident optical system having a half angle of at least 60° and a comparatively simple structure irrespective of a type of an optical element used.

Abstract: A luminous flux, from one conjugate surface (A), having an opening angle of at least 10° sequentially passes through a first optical system (30) having a luminous flux convergent action in the vicinity of its reference axis and a second optical system (31) having a luminous flux divergent action in the vicinity of its reference axis, and converges on another conjugate surface (B). A specific condition is given to the converging distance of each converging point at a luminous flux section including a principal ray according to the passing position of the luminous flux through the first optical system (30) to thereby implement an oblique-incident optical system having a half angle of at least 60° and a comparatively simple structure irrespective of a type of an optical element used.

Abstract: A projection lens, which has a first group of lenses having a negative power and a second group of lenses having a positive power, sequentially arranged from an enlargement side to a reduction side, satisfying the following conditional expressions (1) through (4), and having a field angle of about 110° or more: (1) 25.0<Fb, (2) F<0.65H, (3) 30F<|EP|, and (4) 4F<T, where Fb is an air-converted distance (mm) from a final surface at the reduction side of the lens to an image point, H is a maximum image height (mm) at the reduction side, F is a focal distance (mm) of the whole projection lens, EP is a exit pupil distance (mm), and T is an air-converted distance (mm) obtained by air-converting a gap between the first group of lenses and the second group of lenses.

Abstract: A monolayer or multilayer film has a single layer or multiple layers of silica containing fluorine. An optical element has the forgoing film laid on a surface of a substrate. A concentration of the fluorine in the layer or layers of silica is not less than 0.1 mol % (referably, not less than 1 mol %) nor more than 10 mol %.

Abstract: A projection lens of the retrofocus type that has a long back focus and that can project with a high contrast, exhibits small aberrations and converts a light path inside the lens. A first lens set having a negative refractive power, a light path converter, and an iris and a second lens set having a positive refractive power and an aspheric lens are disposed in order from the screen side. The first lens set includes a lens set having a negative refractive power and one or more aspheric lenses, a bending mirror serving as the light path converter, and a lens set having a positive refractive power. The lenses in the first lens set have an outer shape with a portion thereof cut outside an effective light ray in a direction of the light path conversion, and the direction of the light path conversion is a direction of a shorter side of rectangular image formation element.

Abstract: An optical projection lens system for microlithography comprising in the direction of propagating radiation: a first lens group having positive refractive power, a second lens group having negative refractive power and comprising a waist (constriction) with a minimum diameter of the propagating radiation, and a further lens arrangement with positive refractive power, which follows the second lens group, wherein at least one lens of the projection lens system which is arranged in front of the waist comprises an aspherical surface.

Abstract: A collimating lens and a collimating system which condense light emitted from a light source with directivity at a high efficiency and a projection type image displaying apparatus using the same. The collimating system includes a light source having at least one dominant emitting angle at which light having a relatively great intensity distribution is emitted and a collimating lens including at least one prism portion having an exit surface sloping at a prism angle corresponding to the dominant emitting angle.

Abstract: An aberration changing optical system to be used with a projection optical system of a projection exposure apparatus, includes an optical element having at least one of a cylindrical surface and a toric surface and being rotatable about and tiltable to an optical axis of the optical system. In another form, the aberration changing optical system includes an optical element having different refracting powers in two orthogonal directions or having a refracting power only in one direction, the optical element being made rotatable about and tiltable to an optical axis of the optical system.

Abstract: A projection optical system that projects an image on a first side onto a second plane through a plurality of lenses includes the following elements in order from the first side to the second plane: a first lens group that has a negative refractive power, a second lens group that has a positive refractive power, a third lens group that has a negative refractive power, a fourth lens group that has an aperture stop in the optical path, and a fifth lens group that has a positive refractive power. A clear aperture of a lens surface or an outer diameter of a lens in the projection optical system has a relative maximum in the second lens group, a relative minimum in the third lens group, and a relative maximum in the third-fifth lens groups, and has only one significant minimum between the first side and the second plane.

Abstract: According to one exemplary embodiment, a projection lens having an object plane and an image plane is provided and includes the following lens groups listed objectwise to imagewise: (1) a first lens group having negative refractive power; and (2) at least three other lens groups having a positive refractive power and at least one other lens group having a negative refractive power. In one embodiment, the projections lens includes a second lens group having a positive refractive power; a third lens group having a negative refractive power; and fourth, fifth and sixth lens groups having overall positive refractive power. The projection lens having a numerical aperture of at least about 0.85 and is of a 1½ waist construction, with the ½ waist defined in the first lens group and a primary waist is defined in the third lens group.

Abstract: A projection objective has at least five lens groups (G1 to G5) and has several lens surfaces. At least two aspheric lens surfaces are arranged so as to be mutually adjacent. These mutually adjacently arranged lens surfaces are characterized as a double asphere. This at least one double asphere (21) is mounted at a minimum distance from an image plane (0?) which is greater than the maximum lens diameter (D2) of the objective.

Abstract: A projection optical system is disclosed that includes six lens groups, four of which are positioned in pairs symmetrically about a stop. The second and fifth lens groups, in order from the object side, may be positioned symmetrically about the stop but are also adjustable asymetrically about the stop in order to adjust the magnification of the projection optical system. The first and sixth lens groups, in order from the object side, function to make the projection optical system substantially telecentric on both the object side and the image side, respectively. Also disclosed is a projection and light exposure apparatus that uses the projection optical system of the present invention. The projection and light exposure apparatus automatically detects the image magnification and, based on the detection result, adjusts the positions of the second and fifth lens groups G2 and G5 as a unit so as to maintain a specified magnification.

Abstract: The invention discloses a projection optical system for projecting an original image onto a projection surface. The projection optical system comprises a plurality of aspherical curved mirrors, which reflects image light from the original image in sequence and then forms an image on the projection surface. The projection optical system forms a projected image on the projection surface at an aspect ratio different from that of the original image by a combination of reflective actions of the image light on the aspherical surfaces of the plurality of aspherical curved mirrors. Even in a projection optical system having a wide angle of view and a short distance of projection, it is possible to implement a projection optical system that is capable of suppressing distortion and performing an optical aspect conversion.

Abstract: A purely refractive projection objective suitable for immersion micro-lithography is designed as a single-waist system with five lens groups, in the case of which a first lens group with a negative refracting power, a second lens group with a positive refracting power, a third lens group with a negative refracting power, a fourth lens group with a positive refracting power and a fifth lens group with a positive refracting power are provided. The system aperture is in the region of maximum beam diameter between the fourth and the fifth lens group. Embodiments of projection objectives according to the invention achieve a very high numerical aperture of NA>1 in conjunction with a large image field, and are distinguished by a good optical correction state and moderate overall size. Pattern widths substantially below 100 nm can be resolved when immersion fluids are used between the projection objective and substrate in the case of operating wavelengths below 200 nm.

Abstract: A refractive projection objective for use in microlithography with lenses made exclusively of one and the same material has an image-side numerical aperture larger than 0.7. A light bundle defined by the image-side numerical aperture and by the image field has within the objective a variable light-bundle diameter smaller than or equal to a maximum light-bundle diameter. In a length interval measured on the optical axis from the system diaphragm towards the object field and at least equaling the maximum light-bundle diameter, the variable light-bundle diameter exceeds 85% of the maximum light-bundle diameter.

Abstract: A projector lens system includes a negative first lens group and a positive second lens group. The first lens group comprises a first lens element that is formed as a negative meniscus lens element, a positive or negative second lens element, a negative third lens element, a positive fourth lens element that is cemented to or separated from the third lens element, and a negative fifth lens element. The first lens group satisfies condition (1) with respect to the refractive power thereof, and satisfies condition (2) with respect to the refractive power of the negative first lens element of the negative first lens group: 0.6<fw/|fI|<1.0(fI<0)??(1) 0.3<fI/f1,1<0.7??(2) wherein fw: focal length of the entire projector lens system at the wide-angle extremity; fI: the focal length of the negative first lens group; and f1,1: the focal length of the negative first lens element of the negative first lens group.

Abstract: In a projection optical system projecting an image displayed on a predetermined play surface onto a predetermined projection surface, two decentering lens units movable in directions vertical to the optical axis and substantially vertical to each other are included between a rear lens unit situated on the display surface side and a front lens unit situated on the projection surface side, a driving mechanism is provided that reciprocates the two decentering lens units in the directions vertical to the optical axis. When the focal lengths of the two decentering lens units are FD1 and FD2, respectively, and the focal length of the rear lens unit is FR, the relationships 0.01?|FR/FD1|?0.2 and 0.01?|FR/FD2|?0.2 are satisfied.

Abstract: A luminous flux, from one conjugate surface (A), having an opening angle of at least 10° sequentially passes through a first optical system (30) having a luminous flux convergent action in the vicinity of its reference axis and a second optical system (31) having a luminous flux divergent action in the vicinity of its reference axis, and converges on another conjugate surface (B). A specific condition is given to the converging distance of each converging point at a luminous flux section including a principal ray according to the passing position of the luminous flux through the first optical system (30) to thereby implement an oblique-incident optical system having a half angle of at least 60° and a comparatively simple structure irrespective of a type of an optical element used.

Abstract: A projection zoom lens system that is suited to a projector with a DMD is provided. The zoom lens system includes a fixed fifth lens group that is positioned on the light modulator side and is used as the field lens that transmits the illuminating light and the projection light and a first lens group for focusing that is fixed during zooming, and is constructed of five groups arranged in negative, positive, positive, negative, positive order from the screen side. The third lens group moves significantly during zooming as a variator, the second and fourth lens groups travel only so small distances as compensators but can correct various aberrations so well. Therefore, the movement of the fourth lens group that is the entrance pupil for the projection light outputted from the light valve is small, so that the active projection light is efficiently taken in and a projection zoom lens system that can project bright, clear images can be provided.

Abstract: A projection optical system includes a plurality of positive lens groups having a positive refractive power, and at least one negative lens group having a negative refractive power, wherein, when L is a conjugate distance of the projection optical system and ?0 is the sum of powers of the or each negative lens group, a relation |L×?0|>17 is satisfied, wherein, when h is a height of an axial marginal light ray and hb is a height of a most abaxial chief ray, at least two aspherical surfaces are formed on surfaces which satisfy a relation |hb/h|>0.35, wherein, when ?ASPH is an aspherical amount of each aspherical surface, a relation |?ASPH/L|>1.0×10?6 is satisfied, and wherein the at least two aspherical surfaces include regions in which, from a central portion toward a peripheral portion of the surface, their local curvature powers change with mutually opposite signs.

Abstract: This invention provides a relay imaging optical system which is composed of a small number of lenses and can be miniaturized and reduced in weight with maintaining required optical characteristics. This relay imaging optical system is provided for forming an image of a first plane (10) on a second plane (M), and comprises a first lens group G1 which is constructed so that an image plane thereof is positioned within a limited range, a second lens group G2, and a third lens group G3, from the first plane side. At least two lens groups of the first lens group through the third lens group have at least one aspheric surface respectively; and the total number of lenses which constitute this optical system are ten or fewer.

Abstract: A method and system for a conductive lens. In one method embodiment, the present invention forms a silver flash layer on a lens. A polyester sheet is then applied over the silver flash layer. Openings are utilized in the polyester sheet to expose an edge portion of the silver flash layer. A conductive bus layer is then applied around the edges of the lens, the conductive bus providing an electrical coupling between the silver flash layer and the conductive bus. In so doing, a lens that is visually transparent but electromagnetic interference (EMI) opaque is formed.