Abstract: Telecentric projection lenses for use with pixelized panels (PP) are provided. The projection lenses have a negative first unit (U1) which has at least one negative meniscus element (N1) having at least one aspheric surface and a positive second unit (U2) which has at least one positive element (P1) having at least one aspheric surface. The lens' aperture stop (AS) is located between the two units, and a third lens unit (U3) may be used in the vicinity of the aperture stop to improve the correction of axial color. The lenses have small forward vertex distances, small clear apertures, and long back focal lengths which make them particularly well-suited for use in the manufacture of compact projection systems.

Abstract: A transparent member having refractive power as a result of curved surface thereon is used in one or more light paths of a three-color projection device in order to correct for the lateral color aberration of the projection lens. The transparent member is positioned between one or more optical modulation element(s) and the beam combining prism of a prism optical system, or alternatively, is on or affixed to the beam combining prism surface. When correcting an image that is enlarged by the projection lens, the curved surface of the transparent member should be convex and positioned on the side of the transparent member nearest the display panels. The focal length of a correction lens that optimally corrects the lateral color of the projection lens depends on the maximum image height at the image input display panel, the lateral color aberration generated by the projection lens, and the air conversion length from the image input display panel to the on axis position of the curved surface.

Abstract: An electronic imaging system is disclosed, for assessing the intensity of calorimetric, fluorescent or luminescent signal in a matrix consisting of wells, microwells, hybridization dot blots on membranes, gels, or other specimens. The system includes a very sensitive area CCD detector, a fast, telecentric lens with epi-illumination, a reflective/transmissive illumination system, an illumination wavelength selection device, and a light-tight chamber. A computer and image analysis software are used to control the hardware, correct and calibrate the images, and detect and quantify targets within the images.

Abstract: A retrofocus lens system has a negative first, a positive second and a positive third lens group. The first lens group includes an aspheric first lens, a negative meniscus second and third lenses that are convex on the large conjugate side, and a negative meniscus fourth lens being convex on the small conjugate side. The second lens group includes a positive fifth lens and a sixth lens joined to the fifth lens. The third lens group includes a positive meniscus seventh lens being convex on the small conjugate side, a biconcave eighth lens, a positive ninth lens joined to the eighth lens, a biconvex tenth and eleventh lenses, and an aspheric twelfth lens. The system satisfies 0.8<f2/f3<1.5, 1.6<|f1|/f<2.

Abstract: A high-resolution variable focus lens system that has an extra-long back focal length with a telecentric design. The lens system includes three groups of lenses between an object (screen) and an image (a liquid crystal panel). The first group of lenses, comprising three lenses and having a negative power, is used for focusing and zooming of the lens system. The second group of lenses, comprising two lenses and having also a negative power, is used for zooming of the lens system. The third group of lenses, comprising six lenses and having a positive power, is similarly used for zooming of the lens system.

Abstract: An illumination apparatus that can adjust telecentricity of beams on a wafer without reducing the use efficiency of light is provided. The illumination apparatus moves an inner surface reflection type optical integrator in a direction orthogonal to an optical axis, and thus shifts light intensity distribution on a light emission surface thereof, thereby shifting the baricenter of the light intensity distribution on a light incident surface of multi-beam generation means. Therefore, the telecentricity of image-forming beams on the axis may be adjusted.

Abstract: Projection lenses and projection lens systems are telecentric between an illumination subsystem and a set of imagers. The lenses and systems can exhibit color fringing correction, uniform imager illumination, athermalization, and component articulation for improved imaging. The lenses and systems may be employed in display apparatuses, such as folded display apparatuses that have decreased footprint size, but long effective projection lengths.

Abstract: An optical system for imaging an array of light sources includes an array of microlenses disposed to intercept light from respective light sources in the array of light sources to reduce the divergence angles of light emanating from the light sources, a first array of lenses (sometimes referred to as minilenses), a second array of lenses (minilenses), and an additional array of microlenses disposed to intercept and focus light from the second array of lenses. Each lens in the first array is sized to intercept light from a respective sub-plurality of the microlenses, and each lens in the second array intercepts and focuses light from a respective lens in the first array. The first and second arrays of minilenses are preferably configured to define a doubly-telecentric imaging system.

Abstract: A multiple element color-corrected doubly telecentric lens and imaging system useful for imaging multiwell plates is described. The lens contains a biconvex field lens element L1, a positive meniscus lens element L2, concave toward the incident light side, a double-Gauss lens element group, a positive meniscus lens element L10, convex toward the incident light, a positive meniscus lens element L11, convex toward the incident light, and a plano concave field flattener lens element L12, concave toward the incident light side. The lens is very sensitive, and can be used to image scintillation proximity assays in multiwell plates.

Abstract: A reflective telecentric lens which uses an on-axis type concave mirror in a pseudo-off-axis manner to avoid blockage of a portion of the field of view. The concave mirror used in a pseudo-off-axis manner permits the telecentric stop, imaging lens, and film or an electronic detector to be moved outside of the field of view.

Abstract: The present invention provides an illumination system for varying the size of an illumination field incident to a scattering optical element. The illumination field is subsequently imaged to a reticle in a photolithographic process. The illumination system includes, in series along an optical axis of the illumination system, an optical source, a beam conditioner, a first optical integrator, a first or input collimating lens, a zoom array integrator (ZAI), a second or output collimating lens, the optical scattering element, a relay lens, and the reticle. The ZAI includes an assembly of fixed and moveable lens components arranged to vary the size of the illumination field throughout a zoom range of the ZAI while maintaining telecentric illumination at a substantially fixed numerical aperture. Illumination telecentricity and substantially fixed numerical apertures are maintained at both the scattering optical element and the reticle throughout the zoom range.

Abstract: An electronic imaging system is disclosed, for assessing the intensity of calorimetric, fluorescent or luminescent signal in a matrix consisting of wells, microwells, hybridization dot blots on membranes, gels, or other specimens. The system includes a very sensitive area CCD detector, a fast, telecentric lens with epi-illumination, a reflective/transmissive illumination system, an illumination wavelength selection device, and a light-tight chamber. A computer and image analysis software are used to control the hardware, correct and calibrate the images, and detect and quantify targets within the images.

Abstract: A telecentric imaging lens system and video camera are mounted above a work support for reciprocation toward and away from an object positioned for inspection on the support. The system includes a lens barrel having therein a plurality of lenses and an adjustable iris diaphragm for projecting an image of an object from a stop opening in the diaphragm to an image inlet end of a zoom lens housing having an image outlet end connected to the camera to transmit the image of an inspected object to an image plane in the camera. The zoom lens housing has therein a plurality of movable zoom lens groups for projecting a magnified image of the object to the image plane in the camera; and the zoom lens groups are adjustable axially of the housing to alter the magnification of the image projected to the camera.

Abstract: Projection lenses and projection lens systems are telecentric between an illumination subsystem and a set of imagers. The lenses and systems can exhibit color fringing correction, uniform imager illumination, athermalization, and component articulation for improved imaging. The lenses and systems may be employed in display apparatuses, such as folded display apparatuses that have decreased footprint size, but long effective projection lengths.

Abstract: An eyepiece lens assembly including a collecting lens, glass spherical cemented doublet, a plastic singlet, and a glass spherical singlet. The assembly provides over 30 degrees extended field of view, a greater than 30 mm eye relief, under 5% distortion, a substantially telecentric focal plane, and weighing under 6 ounces.

Abstract: A multiple element color-corrected doubly telecentric lens and imaging system useful for imaging multiwell plates is described. The lens contains a biconvex field lens element L1, a positive meniscus lens element L2, concave toward the incident light side, a double-Gauss lens element group, a positive meniscus lens element L10, convex toward the incident light, a positive meniscus lens element L11, convex toward the incident light, and a plano concave field flattener lens element L12, concave toward the incident light side. The lens is very sensitive, and can be used to image scintillation proximity assays in multiwell plates.

Abstract: A telecentric zoom lens having telecentric forming aperture optically and preferably mechanically intermediate an objective lens and a zoom group. The aperture is fixed along an optical axis and selected to provide a constant speed on an image side of the lens system. The location of the aperture relative to the zoom group maintains telecentricity of the lens in object space.

Abstract: Projection lenses and projection lens systems are telecentric between an illumination subsystem and a set of imagers. The lenses and systems can exhibit color fringing correction, uniform imager illumination, athermalization, and component articulation for improved imaging. The lenses and systems may be employed in display apparatuses, such as folded display apparatuses that have decreased footprint size, but long effective projection lengths.

Abstract: An optical device and a viewing method having a higher magnification viewing area located substantially centrally in a lower magnification area, whereby the structure facilitates locating viewing object within in higher magnification viewing area.

Abstract: Disclosed is an imaging optical system and an image forming apparatus that provide a small-size design and high resolution. An optical system (telecentric optical system) between the composite focus 4d of an imaging surface side and a laser array 1 is divided into a second lens group 4b and a third lens group 4c and the distance D2 between the third lens group 4c and the laser array 1 is shortened, whereby the spread of incident light into the third lens group 4c is reduced and the aperture of the third lens 4c is reduced. Also, the principal light beam 2a of beam 2 from the laser array 1 is bent at two stages, the second lens group 4b and the third lens group 4c, and the distance D1 between the second lens group 4b and the third lens group 4c is increased, whereby the bend of the principal light beam 2a of the laser beam 2 in the second lens group 4b and the third lens group 4c is reduced, with the result that small aberration is obtained.

Abstract: A projection lens (400) having a BFD:EFL, ratio in the range of 0.80:1 to 1.60:1, an air equivalent BFD of at least 4.3 inches, a throw ratio in the range of 3:1 to 6:1, and lateral color correction of one-quarter pixel when used with an SXGA modulator having pixels on 0.17 &mgr;m centers, and operating with its chief rays telecentric at the plane of the modulator. The projection lens comprises an objective lens group (402), a telecentric lens group (404), and an aperture stop (414) between the objective lens group and the telecentric lens group.

Abstract: A multiple element color-corrected doubly telecentric lens and imaging system useful for imaging multiwell plates is described. The lens contains a biconvex field lens element L1, a positive meniscus lens element L2, concave toward the incident light side, a double-Gauss lens element group, a positive meniscus lens element L10, convex toward the incident light, a positive meniscus lens element L11, convex toward the incident light, and a plano concave field flattener lens element L12, concave toward the incident light side. The lens is very sensitive, and can be used to image scintillation proximity assays in multiwell plates.

Abstract: It is an object to provide a high-performance and compact exposure apparatus which can perform a projection exposure operation with satisfactory optical performance by using a plurality of compact projection optical systems each capable of ensuring a sufficient working distance and having excellent imaging performance, while preventing a decrease in throughput even in a large exposure area. An exposure apparatus for projecting and exposing an image of a mask onto a plate while moving a mask and a plate has a first projection optical system and a second projection optical system each of which is real-size and both-side telecentric and forms the erect image of the mask on the plate. The first or second projection optical system has a refraction optical system having a positive refracting power, and a concave reflecting mirror for reflecting a light beam from the refraction optical system toward the refraction optical system.

Abstract: A projection lens which has a wide angle view, a short projection distance and telecentricity, and in which the projection can be performed with high contrast, various aberrations such as a distortion aberration are reduced and the optical path is converted by providing a first lens group having negative refractive power and second and third lens groups having positive refractive power are arranged from a longer conjugate side. Representing a back focus at a projection distance of an infinite point by BF; the composite focus distance of the entire system by F; a center distance between said first lens group and said second lens group by GD1; the composite focus distance of said first lens group by F1; the composite focus distance of said second lens group and said third lens group by F23; and the center distance between said second lens group and said third lens group by GD2, the following relationships are satisfied:[2.8<BF/F],[3.0<GD1/F<4.50],[0.40<-F1/F23<0.48],and[0.40<GD2/F23<0.8].

Abstract: An optical system for non-flexible endoscopes comprising an illumination optical system and an observation optical system which are disposed in an insert section, wherein the observation optical system comprises, in order from a tip thereof, an objective optical system and a single cycle type relay optical system, and an outside diameter D1 of a lens component in the objective optical system whichever has a largest outside diameter, an outside diameter D2 of a lens component in the relay optical system whichever has a largest outside diameter and an outside diameter D3 of the insert section are in relationship expressed by the following conditions (1) and (2):L/D1<20 (1)0.7<D2/D3<0.9 (2).

Abstract: The invention is directed to an afocal zoom system for a surgical microscope. The zoom system has an even number of members and is symmetrically configured.

Abstract: A compact optical system for imaging an array of light emitters, particularly an individually addressable laser diodes array, onto a recording surface, whereby the image of each emitting region is spread in the cross direction to a width approximately equal to its length dimension. The system consists of a main non-anamorphic imaging lens assembly and a single cylindrical lens disposed between the array and the imaging lens assembly, with its focal line parallel to the array's centerline. There will occur a spread of the short dimension of the imaged emitting regions due to defocusing at the recording surface. Also, the numerical aperture of the emitted beams in the transverse axis is reduced prior to entry into the imaging lens assembly.

Abstract: A retrofocus projection lens system comprising, in order from a large conjugate side a first lens group having a negative refracting power and including a plurality of lenses, a second lens group having a positive refracting power, and a third lens group having a positive refracting power and including a plurality of lenses. The lens of the first lens group which is nearest to the large conjugate side is an aspherical lens, and the lens of the third lens group which is nearest to a small conjugate side is an aspherical lens. The retrofocus projection lens system desirable satisfy the following conditional expressions (1) to (3):1.8<D.sub.1 /f<3.0 (1)1.1<f.sub.2 /f.sub.3 <1.6 (2)1.5<.vertline.f.sub.1 .vertline./f<2.3 (3)where a symbol f.sub.1 designates a focal length of the first lens group, a symbol f.sub.2 designates a focal length of the second lens group, a symbol f.sub.

Abstract: A zoom lens system is provided with, from the object side, a first lens unit having a negative optical power, a second lens unit having a positive optical power, a third lens unit having a negative optical power, and a condenser lens unit having a positive optical power. In this zoom lens system, zooming is performed by varying the distances between the first, the second, the third lens unit, and the condenser lens unit. Additionally, this zoom lens system fulfills the condition below:-1.5<.phi.1/.phi.C<-0.4where .phi.1 represents the optical power of the first lens unit, and .phi.C represents the optical power of the condenser lens unit.

Abstract: The invention pertains to optical projection-exposure apparatus for photolithography that can focus a pattern defined by a mask onto a non-flat substrate. In one embodiment, piezoelectric elements are used as an actuator for adjusting the optical path length between the mask and the substrate. A first reflector reflects a light flux transmitted by the mask. A telecentric optical system then forms an image of the mask in a focal plane. A second reflector reflects the light flux from the telecentric perpendicularly onto the substrate. The actuator moves the first or second reflectors, changing the optical path length of the light flux. A focus sensor detects the height of the sensitized surface of the substrate in a direction perpendicular to the sensitized surface of the substrate and thereby provides a focus signal to the actuator. The actuator then moves the focal plane to the sensitized surface.

Abstract: Negative, positive, and positive lens groups are disposed successively from the larger conjugate length side, and focal length adjustment is effected by the convex lens disposed on the smallest conjugate length side of the first lens group, thereby yielding a long back focus and a telecentric characteristic, decreasing distortion and chromatic aberration, and simplifying the focusing structure. Successively from the larger conjugate length side, a first lens group G.sub.1 having a negative refracting power and including a convex lens L.sub.5 disposed on the smallest conjugate length side, a second lens group G.sub.2 having a positive refracting power and causing a luminous flux diverged by the first lens group G.sub.1 to become substantially afocal, and a third lens group G.sub.3 having a positive refracting power are disposed, and the convex lens L.sub.5 disposed on the smallest conjugate length side of the first lens group G.sub.1 is moved on an optical axis so as to effect focus adjustment.

Abstract: A wide-angle lens has a three-group configuration in which a plastic aspherical lens is used in the first lens group on the enlargement side, and predetermined conditional expressions concerning focal lengths of individual lenses constituting the first lens group are satisfied, whereby image quality is restrained from deteriorating due to changes in temperature, and a telecentric characteristic is attained such that no vignetting occurs in marginal luminous fluxes, thus making various kinds of aberration favorable and allowing the cost to be cut down. The first lens group G.sub.1 disposed on the enlargement side has a three-lens configuration in which the first lens L.sub.1 on the enlargement side and the third lens L.sub.3 on the reduction side are constituted by a plastic aspherical lens having a negative refracting power and a plastic aspherical lens having a positive refracting power, respectively. Letting the focal length of the first lens group G.sub.1 be F.sub.

Abstract: In the projection optical system that projects an image of the first object onto the second object with a fixed reduction ratio and a projection aligner equipped therewith, said projection optical system comprises, viewed from said first object side, in order of succession, the first group of lenses with positive refractive power, and the second group of lenses virtually consists of afocal system, and the third group of lens with positive refractive power, and if the focal length of said projection optical system is represented by F, the projection magnification ratio of said projection optical system is represented by B, the distance between said first object and said second object is represented by L, the distance from said first object to the lens surface that is closest to said first group of lenses is represented by d.sub.0, the focal length of said first group of lenses is represented by f.sub.1, and the focal length of said third group of lenses is represented by f.sub.

Abstract: A Gauss lens achieves a high reading density when used with an imaging magnification of about 0.16535 and reduces the cost while providing a sufficient angle of view and brightness. The Gauss lens includes: a first lens group including a first lens having a positive meniscus shape; a second lens group including a second lens having a positive meniscus shape and a third lens having a negative meniscus shape, the second and third lenses being connected with each other; a third lens group including a fourth lens having a negative meniscus shape and a fifth lens having a positive meniscus shape, the fourth and fifth lenses being connected with each other; and a fourth lens group including a sixth lens having a positive meniscus shape, wherein the following conditions are satisfied:(1) n.sub.2 <1.53,(2) .nu..sub.2 <66.0,(3) n.sub.3 <1.63,(4) .nu..sub.3 <38.0,(5) 25.0<.nu..sub.2 -.nu..sub.3 <35.0,(6) 0.30<(R.sub.3 +R.sub.5)/R.sub.4 <0.60,(7) 0.24<(D.sub.5 +D.sub.6)/f<0.28,(8) 0.

Abstract: A projection lens, which is as fast as 1.5 or thereabout in F-number and has an excellent telecentric property, includes, in order from a screen side, a first lens unit having a positive refractive power in a retrofocus form and a second lens unit. The first lens unit includes, in order from the screen side, at least two negative meniscus lenses convex toward the screen side, a positive lens having a refractive power on the screen side which is stronger than that of an opposite surface thereof, a positive lens having a refractive power on an image generating plane side which is stronger than that of an opposite surface thereof, a cemented lens composed of a negative lens and a positive lens and having a cemented surface convex toward the screen side, and at least one positive lens. The second lens unit includes, in order from the screen side, at least one positive lens and a negative lens having a refractive power on the screen side which is stronger than that of an opposite surface thereof.

Abstract: Provided is a color-image-reading Gaussian lens for reading out color images, color originals, or negative or positive films, which is suitably used at a low magnification of -1/2.5.times. to -1/1.25.times., effectively corrects axial chromatic aberration in particular, and exhibits high performances in a wide wavelength range. A six-sheet Gaussian lens comprises, successively from an object side, two convex lenses, two concave lenses, and two convex lenses, while a stop is disposed between the two concave lenses. In particular, the following conditional expressions are satisfied:0.10<D.sub.5 /f<0.230.82<R.sub.5 /.vertline.R.sub.6 .vertline.<1.30.0012<.SIGMA.(.phi..sub.i .multidot..delta..theta..sub.i)<0.0045where .phi. is refracting power, and .delta..theta. is anomalous dispersion.

Abstract: An offset reverse telephoto projection lens that is telecentric in modulator space and has an air equivalent back focal distance of at least 3.3 inches and preferably at least 4.0 inches. The lens comprising, from the image side, a first objective lens group 408 having a negative power and a second telecentric lens group having a positive power. The second telecentric lens group 410 is telecentric in object space such that the image of the aperture is focused at infinity and light converges on the object plane perpendicular to the axis of the lens. Embodiments of the lens have a back focal distance to effective focal length ratio of at least 0.86:1, preferably at least 1.2:1, more preferably at least 1.3:1, still more preferably at least 4.08:1, and most preferably 5.0:1. The embodiments described have a field of view between 14 degrees and 73 degrees, have throw ratios of 1.2:1 to 7:1, and an overall length ranging from less than 5 inches to 12.5 inches.

Abstract: A telecentric laser beam optical focusing system consists of two diffractive optical elements. The optical system has a spot size of less than one micron and a Strehl ratio of over 0.9 with a f/number of one and a total object/image field of 0.5 micron.

Abstract: A telecentric projection lens system comprises, in order from the magnifying side to the reducing side, a positive power first lens group including, in order from the magnifying side, at least first and second concave meniscus lens elements and one cemented lens element, a negative power second lens group comprising a concave lens element and a convex meniscus lens element, and a positive power third lens group, and satisfies the following conditions:0.75<f1/f<1.20f2/f<-1.201.20<f3/f<1.70where f is the overall focal length of the telecentric projection lens system at the standard projection distance, f1, f2 and f3 are the focal lengths of the first, second and third lens groups.

Abstract: A level-setting attenuator for generating an output signal having a predetermined optical power from an input optical signal having a varying power is disclosed. The level-setting attenuator includes a telecentric imaging device, a variable atttenuator, an optical power detector and control electronics. The telecentric imaging device collimates a received optical signal which is received and partially attenuated by the variable attenuator. In some embodiments, the variable attenuator generates an attenuated signal portion and an unattenuated signal portion. The attenuated signal is directed, by the variable attenuator, to an optical power detector operable to measure the power of the attenuated optical signal. The detector sends a signal indicative of the measurement to control electronics. The control electronics are operable to generate a control signal for controlling the attenuation of the unattenuated signal portion so that is has the predetermined power level.

Abstract: Projection lenses for use with pixelized panels, e.g., LCD panels, are provided. The lenses have a large focus range, e.g., a focus range of greater than 0.05 and in many cases greater than 0.1, and a limited (mini) zoom range, e.g., a zoom range of less than 15% (.+-.7.5% from the center of the range). By limiting the zoom range, complex lens structures involving large numbers of lens elements are avoided. In particular, the lenses employ at most one additional lens element and in many cases no additional lens elements compared to non-zooming lenses having a similar focus range.

Abstract: A projection lens for use with LCD panels is provided. The lens has two aspherical meniscus elements which are concave to each other and are located in the vicinity of the lens' aperture stop and a color-correcting doublet which provides most of the positive optical power of the lens. The lens can also include an aspherical corrector lens element of weak optical power which is located on the side of the two meniscus elements opposite to the color correcting doublet.

Abstract: A projection optical system that projects an image of an object in an object surface onto an image surface with a fixed reduction magnification comprises, in light path order from the object surface: a first group of lenses with positive refractive power; a second group of lenses forming an approximately afocal system; and a third group of lenses with positive refractive power. The projection optical system has a focal length F, the projection optical system has a projection magnification B, the object surface and the image surface are separated by a distance L, and a lens surface in the first group of lenses that is closest to the object surface is separated from the object surface by a distance d.sub.0. A paraxial marginal ray from an axial object point on the object surface enters the second group of lenses G.sub.2 at an entrance height h.sub.1 from an optical axis, and the paraxial marginal ray from the axial object point on the object surface emerges from the second group of lenses G.sub.

Abstract: A wide angle lens is made of three groups so as to satisfy a predetermined conditional expression concerning abbe number, thereby making it telecentric and yielding no eclipse in its peripheral luminous flux. Also, an apparatus accommodating it is made compact as a whole. This wide angle lens comprises, arranged in the following order from the screen side toward the liquid crystal side, a first lens group composed of a concave lens (L1), whose concave surface having a large radius of curvature is directed toward a smaller conjugate side (liquid crystal panel), and a convex lens (L2); a second lens group composed of one concave lens (L3) and two convex lenses (L4) and (L5); and a third lens group composed of a Fresnel lens (L6) which is disposed near a liquid crystal panel (L7; 4). The abbe number .nu. 1 of the lens L1 which is the concave lens in the first lens group is 57.8, whereas the abbe number .nu. 2 of the lens (L3) which is the concave lens in the second lens group is 25.

Abstract: Lens systems are disclosed each of which providing a variable magnification telecentric optical system in which lateral magnification can be varied while maintaining constant image position and telecentricity. The lens system comprises, from the object side, first, second, and third lens groups disposed on an optical axis. The first and third lens groups each have positive refractive power. The second lens group is afocal. While varying the lateral magnification, the object and image positions remain fixed and telecentricity of the lens system (on both the object and image sides) is maintained. Lateral magnification is varied by axially moving lenses in one or more of the first, second, and third lens groups.

Abstract: In the projection optical system that projects an image of the first object onto the second object with a fixed reduction ratio and a projection aligner equipped therewith, said projection optical system comprises, viewed from said first object side, in order of succession, the first group of lenses with positive refractive power, and the second group of lenses virtually consists of afocal system, and the third group of lens with positive refractive power, and if the focal length of the overall system is represented by F, the projection magnification ratio of said projection optical system is represented by B, the distance between said first object and said second object is represented by L, and when a ray from the second object side of said projection optical system that is parallel to the optical axis of said projection optical system is incident on said projection optical system, a distance between a point where an extension on the first object side of said ray intercepts the optical axis and said first ob

Abstract: An objective lens system for an endoscope having an image transfer optical fiber bundle comprises from the object end a first lens of negative power having a concave image side surface, a second lens of positive power having a radius of curvature greater on an image side than on an object side, a third lens of positive power having a radius of curvature greater on the object side than on the image side, a doublet lens of positive power which comprises a forth lens element and a fifth lens element, and an aperture diaphragm interposed between the second and third lenses and satisfies the following relations:.vertline.d.multidot.f/f.sub.R.sup.2 .vertline.<0.11v2<45.0where f is the equivalent focal length of the entire objective lens system, f.sub.

Abstract: An display apparatus has an image displaying device for modulating light by a spatial light modulation element and displaying an image, a relay optical system for forming the image on an imaging plane at a location differing from the image displaying device, an eyepiece optical system for directing the light from the imaging plane to an observer's pupil, and light beam controlling device provided in a portion of the relay optical system for controlling the amount of transmission of a light beam from the image displaying device correspondingly to the inclination of the contrast distribution of the light beam.

Abstract: A telecentric zoom lens is disclosed that comprises, in order from the magnifying side to the reducing side on an optical axis: first, second, third, fourth, and fifth lens groups having a positive, negative, negative, positive, and positive focal length, respectively. An open aperture is axially disposed between the third and fourth lens groups at the magnifying-side focal position of the combined fourth and fifth lens groups. When zooming from the maximum wide-angle state to the maximum telephoto state, the first, fourth, and fifth lens groups are stationary, while the second lens group axially moves linearly toward the reducing side and the third lens group axially moves along a convex path toward the magnifying side.

Abstract: The optical unit of an imaging system is disposed between a target object and an image plane, and permits the passage of cones of light from different point sources on the target object therethrough to form an image on the image plane. The optical unit is provided with an aperture stop to control sizes of the cones of light passing through the optical unit. The aperture stop forms an entrance pupil in relation to the optical unit. A rectifying mask, which is formed as an upright opaque plate, is disposed between the target object and the image plane. The aperture stop forms a corresponding aperture stop image on a plane of the rectifying mask, and the rectifying mask has a mask width which is narrower than the width of the corresponding aperture stop image, and a mask height which is greater than the mask width.