Abstract: Provided is a zoom lens, including in order from a magnification conjugate side to a reduction conjugate side: a first lens unit having a negative refractive power; a second lens unit having a positive refractive power; a third lens unit having a positive refractive power; a fourth lens unit having a negative refractive power; a fifth lens unit having a negative refractive power; and a sixth lens unit having a positive refractive power. The first and sixth lens units do not move for zooming, while the second to fifth lens units move to the magnification conjugate side during zooming from a wide-angle end to a telephoto end. Each of the second and third lens units is composed of a single positive lens. Movement amounts of the second, third and fourth lens units during zooming from the wide-angle end to the telephoto end satisfy appropriate relationships.

Abstract: An optical image capturing lens assembly includes, in order from an object side to an image side, a first lens element, a second lens element, a third lens element, a fourth lens element, a fifth lens element, and a sixth lens element. The first lens element with positive refractive power has a convex object-side surface. The object-side surface and the image-side surface of the fifth lens element are aspheric and at least one of the object-side surface and the image-side surface has at least one inflection point formed thereon. The sixth lens element with negative refractive power has a concave object-side surface and a convex image-side surface, wherein the object-side surface and the image-side surface of the sixth lens element are aspheric.

Abstract: Disclosed is an image pickup lens having the following disposed from an object side in the order listed below: a first lens having a negative power and a meniscus shape with a concave surface on an image side; a second lens having a positive power; a third lens having a negative power; a fourth lens having a positive power; a fifth lens having a positive power; and a sixth lens having a negative power and a meniscus shape with a concave surface on the object side. The image pickup lens satisfies Conditional Expression (1) given below when a focal length of the first lens is taken as f1 and a focal length of the second lens is taken as f2 ?3.0<f1/f2<?1.6??(1).

Abstract: There is provided a projection lens unit for a pico-projector which comprises a lens array, a color composition prism, a cover glass and an image panel, the projection lens unit characterized in that: the lens array includes 1st to 6th lenses sequentially arrayed from a screen on which an image is projected, the 1st lens includes a stop side formed on a 1st side of the 1st lens, the stop side stops the passage of light, to perform the function of a diaphragm aperture, light passing from the 1st lens to the 6th lens travels in only one direction of the lens sides based on the diaphragm aperture, and parts of the lens sides through which the light does not pass are cut so that the whole height of the lens array is reduced.

Abstract: An objective lens includes, in order from an object side, a front group having negative refractive power, an aperture stop, and a rear group having positive refractive power, wherein the front group includes, in order from the object side, a first lens which is a negative meniscus lens with a convex surface turned to the object side and a second lens which is a negative lens with a concave surface turned to the object side; the rear group includes, in order from the object side, a positive third lens and a fourth lens made up of a positive lens and a negative lens cemented together, and the objective lens satisfies conditional expression (1) below: ?0.8<f—F/f—R<?0.3 ??(1), where f_F is a focal length of the front group, and f_R is a focal length of the rear group.

Abstract: Provided is a projection optical system. The projection optical system includes: A projection optical system comprising: a first optical part that comprises at least one optical lens, and projects and displays light beams; a second optical part that comprises an image forming element and at least one optical lens, and emits incident light beams as light beams with images; and a third optical part that comprises a light source unit and a deflector that is located between the first and second optical parts, and directs light beams emitted from the light source unit to the second optical part and directs the light beams with images emitted from the second optical part to the first optical part.

Abstract: The present invention relates to an optical unit. The present invention further relates to the use of such an optical unit. Such an optical unit comprises, seen in a direction from the object side to the imaging surface, a first substrate, a first lens element, a flat, transparent intermediate layer, a second lens element and a second substrate, which intermediate layer has an optically correcting function near the imaging surface.

Abstract: An imaging lens includes, in order from an object side, a positive first lens group, a stop, and a positive second lens group. The first lens group includes, in order from the object side, a first lens, which is a negative meniscus lens having a convex object-side surface, and a second lens having a positive power and including a convex image-side surface. The second lens group includes, in order from the object side, a third lens having a negative power and including a concave object-side surface, a fourth lens having a positive power and including a convex image-side surface, a fifth lens, which is a biconvex lens, and a sixth lens, which is a meniscus lens having a negative power and including a convex surface facing an image side. Each of the first to sixth lenses is a single spherical glass lens.

Abstract: An imaging lens system in order from the object side to the image side includes a first lens with negative refractive power, a second lens with positive refractive power, a third lens with negative refractive power, a fourth lens with positive refractive power, a fifth lens with negative refractive power and a sixth lens with positive refractive. The imaging lens system satisfies the following formulas: Nd2>1.8 and Vd2<25, where Nd2 is the refractive index of the second lens, Vd2 is the Abbe number of the second lens.

Abstract: An image capture lens module includes a first compound lens with a first lens element, a second lens element, and a third lens element arranged in sequence from an object side to an image side. A second compound lens includes a fourth lens element, a fourth lens element, and a fifth lens element arranged in sequence from an object side to an image side. A cover glass for an image sensor is positioned behind the second compound lens, wherein the first compound lens, the second compound lens and the cover glass are arranged in sequence from an object side to an image side.

Abstract: An objective lens and a method for using same. The objective lens has a first end, a second end, and a plurality of optical elements. The optical elements are positioned between the first end and the second end and are at least substantially symmetric about a plane centered between the first end and the second end.

Abstract: An imaging lens includes a first lens having a negative power and including a concave surface facing an image side, a second lens having a positive power, a third lens having a positive power, an aperture diaphragm, a fourth lens, which is a biconvex lens having a negative power, a fifth lens having a positive power and including a convex surface facing the image side, and a sixth lens having a positive power and including a convex surface facing an object side, which are arranged in this order from the object side. The Abbe number of a material forming the fourth lens with respect to the d-line is 30 or less. When the focal length of the entire lens system is f and a composite focal length from the fourth lens to the sixth lens is f456, the imaging lens satisfies following conditional expression: 1.00<f456/f<1.88.

Abstract: A zoom lens includes, in order from an object side to an image side, a first lens group having positive refractive power, a second lens group having negative refractive power, a third lens group having negative refractive power, a fourth lens group having positive refractive power, a fifth lens group having positive refractive power, and a sixth lens group having positive refractive power. The zoom lens satisfies the following conditions: (1) 25<TT/fw<27; (2) 8.5 mm<BFL<12.5 mm; and (3) (V2+V5)?(V1+V6)>60. TT is a distance from the object side of the first lens group to the image side of the sixth lens group, fw is a shortest focal length of the zoom lens, BFL is a distance from the image side of the sixth lens group to the imaging sensor, and V1, V2, V5, V6 are Abbe numbers of the first, second, fifth, and sixth lens group, respectively.

Abstract: A miniature image capture lens is disclosed, comprising an aperture diaphragm having an aperture through which an image is captured and a wafer-level lens system, comprising a first lens group including a first substrate, a first lens disposed on a first side of the first substrate and a second lens disposed on a second side of the first substrate, and a second lens group including a second substrate, a third lens disposed on a first side of the second substrate and a fourth lens disposed on a second side of the second substrate. The first lens, the second lens, the third lens and the fourth lens are aspherical and the miniature image capture lens meets the following condition: L/fe<1.6; f1/fe=0.5˜1.5; f2/fe=?1˜?3; Tgroup2/TBFL=0.8˜1.2; Tair/Tgroup2=0.4˜0.

Abstract: A telephoto lens system includes a positive first lens group, a positive second lens group, a diaphragm, a negative third lens group constituting a focusing lens group, and a positive fourth lens group. The first lens group includes a positive first lens element, a positive second lens element, and a negative third lens element. The second lens group includes a negative or a positive fourth lens element and a positive or negative fifth lens element which are cemented to each other. The third lens group includes a positive or negative sixth lens element and a negative or positive seventh lens element which are cemented to each other. The fourth lens group includes one positive eighth lens element. Upon focusing on an object at infinity to an object at a closer distance, the third lens group is moved toward the image. The telephoto lens system satisfies the following conditions.

Abstract: A fixed-focus lens including a first lens group and a second lens group is provided. The first lens group has a negative refractive power, and consists essentially of a first lens, a second lens, a third lens, and a fourth lens arranged in sequence from an object side to an image side. Refractive powers of the first, second, third, and fourth lenses are negative, negative, positive, and negative respectively. The second lens group is disposed between the first lens group and the image side, and has a positive refractive power. The second lens group includes a fifth lens and a sixth lens arranged in sequence from the object side to the image side. Refractive powers of the fifth lens and the sixth lens are both positive.

Abstract: An optical system for imaging an object on an image acquisition unit includes a first lens unit, a second lens unit, a third lens unit, a fourth lens unit, a fifth lens unit, and a sixth lens unit disposed from the object in the direction of the image acquisition unit. The second lens unit is manufactured from a material whose deviation of the relative partial dispersion fulfills the condition: ??gF>0.025. The third lens unit is manufactured from a material whose deviation of the relative partial dispersion fulfills the condition: ??gF<?0.0015. The fifth lens unit is manufactured from a material whose deviation of the relative partial dispersion fulfills the condition: ??gF<?0.005. According to the disclosed system, the secondary spectrum is reduced and a relative aperture is sufficient so that the optical system is usable in a telescopic sight.

Abstract: A fixed focal length lens system comprises a first lens unit and a second lens unit. The first lens unit comprises a plastic negative lens, wherein the first lens unit has a negative diopter, and the plastic negative lens comprises at least one non-spherical surface. The second lens unit comprises a plastic positive lens, wherein the second lens unit has a positive diopter. The fixed focal length lens system satisfies the equation: ?1<2Gf/1Gf<0, wherein 1Gf is the focal length of the first lens unit and 2Gf is the focal length of the second lens unit.

Abstract: A fisheye lens, comprising a front group made up of a total of three groups, which are two concave lenses 1 and 2 whose concave surfaces are directed toward the image side, and a compound lens 3 whose concave surface is directed toward the image side and which has an overall convex or concave refractive power; and a rear group formed by three groups of convex lenses 4, 5, and 6, wherein the front group includes at least one compound lens set, the rear group includes one compound lens set, and at least a first surface of a first concave lens 1 of the front group is an aspheric surface, and satisfies specific conditions. As a result, it is possible to obtain a fisheye lens that can realize a foveal optical system with undiminished illuminance all the way to the periphery and with high resolution over the entire field of view, and with which a wide field of view and an extremely compact size can be attained with a single wide-angle optical system.

Abstract: A zoom lens includes, in sequence from an object side to an image side along an optical axis, first to sixth lens groups respectively having positive, negative, positive, positive, negative, and positive refracting powers. The first lens group includes a reflecting member for bending the optical axis by substantially 90 degrees. The first and third lens groups remain stationary on the optical axis when the zoom lens zooms or focuses. Zooming is performed by moving the second, fourth, and fifth lens groups along the optical axis. Focusing is performed by moving the fourth lens group and/or the fifth lens group along the optical axis. Image shift is performed by moving the sixth lens group in a direction substantially perpendicular to the optical axis. The fourth lens group includes a single positive lens and a single negative lens.

Abstract: An image reading lens is provided and includes: first, second and third lens groups arranged on the object side with respect to the aperture stop; and fourth, fifth and sixth lens groups arranged on the image side. At least all positive lenses, in each lens group, satisfy conditional expression (1) below. At least two positive lenses of the first to third lens groups and at least two positive lens of the fourth to sixth lens groups satisfy the conditional expression (2) below. In the conditional expressions, ?d represents Abbe number at the d-line, and ??g,d represents abnormal dispersion. ?d>60.0??(1) ??g,d>0.

Abstract: A zoom lens includes a first lens unit having a negative optical power located closest to an enlargement side. In the zoom lens, a focal length of the zoom lens at a wide-angle end (fw) and a focal length of the first lens unit (f1) satisfy the following condition: ?2.50<f1/fw<?1.36.

Abstract: A fixed focal length lens system comprises a first lens unit and a second lens unit. The first lens unit comprises a plastic minus lens, wherein the first lens unit has a negative diopter, and the plastic minus lens comprises at least one non-spherical surface. The second lens unit comprises a plastic plus lens, wherein the second lens unit has a positive diopter. The fixed focal length lens system satisfies the equation: ?1<2 Gf/1 Gf<0, wherein 1 Gf is the focal length of the first lens unit and 2 Gf is the focal length of the second lens unit.

Abstract: In a lens group which is disposed forward of a photographing device and which includes at least a ceramic lens that is combined with a glass lens, wherein a conjugate surface of the photographing device by a combined surface between the ceramic lens and the glass lens is formed forward of the combined surface in an optical system that follows an optical system residing between the combined surface and the photographing device.

Abstract: At least one exemplary embodiment is directed to an optical system which includes a plurality of refractive optical elements arranged substantially symmetrically with respect to an aperture-stop. Furthermore the optical system comprises a refractive optical element being constituted by a solid material. An Abbe number ?d of the solid material and a partial dispersion ratio ?gF of the solid material can satisfy the following conditions: ?gF?(?1.665×10?7·?d3+5.213×10?5·?d2?5.656×10?3·?d+0.755)>0, ?gF?(?1.665×10?7·?d3+5.213×10?5·?d2?5.656×10?3·?d+1.011)<0.

Abstract: A front group is formed of a negative first lens as a meniscus lens which is convex at the object side and a negative second lens, and a rear group is formed of a biconvex positive third lens, an aperture stop, a negative fourth lens and a biconvex positive fifth lens. The first lens is a glass lens, and the second lens is a plastic aspherical lens. The following conditions are satisfied: ?2.4<fI/f<?1.55, 0.15<f2/f1<0.35, va<29, and vb>50, where f denotes a focal distance of a whole system, f1 denotes a focal distance of the first lens, f2 denotes a focal distance of the second lens, fI denotes a focal distance of the front group, va denotes an average value of abbe numbers of the third and the forth lenses, and vb denotes an average value of abbe numbers of the rest of the lenses.

Abstract: The invention relates to a projection lens comprising a lens assembly that has at least one first narrowing of the group of light beams. A lens with a non-spherical surface is located in front of and/or behind the first narrowing.

Abstract: A lens system for collecting and focusing light emanating from an object has a cuvette housing the object and having a wall of thickness not greater than 1.5 millimeters; a plano-convex lens having a planar surface affixed to the wall; a sequence of at least three meniscus lenses, each meniscus lens having a concave surface toward the object and a convex surface, each successive meniscus lens receiving the light from the immediately preceding meniscus lens and having radii of curvature of its concave and convex surfaces greater than corresponding radii of the preceding meniscus lens; and at least one compound lens that may be a doublet lens or a triplet lens, the compound lens receiving the light from a last meniscus lens, wherein an image of a geometrical point on the object has a root-mean square spot size equal to or less than 63 ?m.

Abstract: A real image type finder optical system includes an objective lens group having positive refracting power and an eyepiece lens group having a positive refracting power. The objective lens group includes a first group consisting of a negative lens, a second group consisting of a positive lens, a third group consisting of a positive lens and a fourth group having a negative refracting power and forming part of an image inverting optical system. Upon zooming from a wide-angle end to a telephoto end, the first and fourth groups remain fixed and the second and third groups move. The eyepiece lens group comprises a fifth group that forms part of the image inverting optical system and a sixth group having positive refracting power. The resulting real image type finder optical system satisfies specific conditions with respect to the back focus of the first to third groups at the wide-angle end.

Abstract: Before recording data included in a data mask on a holographic medium, the data mask and the holographic medium are aligned by an aligner, which includes a beam supplying unit for supplying an incident laser beam; a transferring unit for receiving the incident laser beam and producing a focused laser beam; a reflecting unit including the holographic medium for receiving the focused laser beam through a pinhole and then reflecting the received laser beam back to the pinhole, wherein the reflected laser beam passing through the pinhole returns to the transferring unit and then is converted into a return laser beam by the transferring unit; and a detecting unit for checking the amount of the return laser beam to determine whether the pinhole and the holographic medium are aligned or not.

Abstract: The invention relates to a projection lens comprising a lens assembly that has at least one first narrowing of the group of light beams. A lens with a non-spherical surface is located in front of and/or behind the first narrowing.

Abstract: A projection objective includes a first lens group (G1) of positive refractive power, a second lens group (G2) of negative refractive power and at least one further lens group of positive refractive power in which a diaphragm is mounted. The first lens group (G1) includes exclusively lenses of positive refractive power. The number of lenses of positive refractive power (L101 to L103; L201, L202) of the first lens group (G1) is less than the number of lenses of positive refractive power (L116 to L119; L215 to L217) which are mounted forward of the diaphragm of the further lens group (G5).

Abstract: A projection objective, particularly for microlithography at 248 nm or 193 nm has, after two bulges and two waists, a pronounced lens arrangement that preferably contains a further waist and the system diaphragm (AS). This is markedly set back from the negative lens group containing the second waist, and is surrounded by important correction devices. The highest numerical aperture (0.65-0.80) is attained with the smallest lens diameters and by paying heed to the further qualities required for such a microlithography projection objective.

Abstract: A Gaussian lens for photography includes, in order from the object side, a front lens group, a stop, and a rear lens group. The front lens group is formed of, in order from the object side, a first lens element and a second lens element, each of positive meniscus shape with their convex surfaces on the object side, and a third lens element that has a negative meniscus shape with its convex surface on the object side. The rear lens group is formed of, in order from the object side, a fourth lens element which has a negative meniscus shape with its concave surface on the object side, and fifth and sixth lens elements each of which is a positive meniscus lens with its convex surface on the image side. Each lens element surface is spaced from any adjacent lens elements so that no lens element surfaces are joined to form a combined lens.

Abstract: A microlithography reduction objective formed from six mirrors arranged in a light path between an object plane and an image plane is provided. The microlithography reduction objective is characterized by having an image-side numerical aperture NA 0.15. In some embodiments, the mirror closest to the image plane, i.e., the fifth mirror is arranged such that an image-side optical free working distance is greater than or equal to a used diameter of a physical mirror surface of the fifth mirror, a physical mirror surface being the area of a mirror where light rays from the object impinge. The fifth mirror may be arranged such that an image-side optical free working distance is greater than or equal to the sum of one-third the used diameter of the physical mirror surface on the fifth mirror and a length between 20 mm and 30 mm. The fifth mirror may be arranged such that the image-side optical free working distance is at least 50 mm, as well.

Abstract: The present invention provides a bright image reading lens coping with high resolution and yet having a great depth of focus and a wide angle of field, and an image reading apparatus using the same. The image reading lens includes, in succession from the object side, six lenses, i.e., a meniscus-shaped positive first lens having its convex surface facing the object side, a second lens of which the both lens surfaces are concave surfaces, a third lens of which the both lens surfaces are convex surfaces, a meniscus-shaped fourth lens having its concave surface facing the object side, a meniscus-shaped negative fifth lens having its concave surface facing the object side, and a meniscus-shaped negative sixth lens having its concave surface facing the object side, and satisfies a predetermined condition.

Abstract: An optical system includes a diffractive optical element in which a phase given to incident light from an optical axis toward the peripheral part in the radial direction is not reversed in an effective area and an absolute value of optical power on the optical axis is made minimum. In the optical system, chromatic aberration of magnification of a high order is satisfactorily corrected and flare caused by additional diffraction light (unnecessary diffraction light) is suppressed to as minimum as possible while maintaining a high imaging performance up to peripheral part of a field angle.

Abstract: Six-component projection lens systems (13) for use in CRT projection televisions (10) are provided. To provide an improved overall modulation transfer function across the field of view of the lens, the system's first lens element (L1) has an object side surface (S2) which has a best fit spherical surface which is convex to the CRT (16). To provide partial axial color correction, the system's second lens element (L2) is made of a high dispersion material, such as styrene.

Abstract: An image capture lens and an image capture apparatus in which various kinds of aberrations are corrected and optical performance suitable for capturing images is obtained. Successively from an object side provided are a first lens group including a negative meniscus lens, a second lens group including a positive lens directing its convex to the object side, a third lend group including a first cemented lens composed of a bi-convex positive lens and a bi-concave negative lens, the first cemented lens having positive refractive power and directing its concave to the object side, a fourth lens group including a second cemented lens composed of a bi-concave negative lens and a bi-convex positive lens, the second cemented lens having negative refractive power and directing its convex surface to an image side, a fifth lens group including a positive lens directing its convex to the image side and a sixth lens group including a negative lens directing its concave to the object side.

Abstract: The projection lens comprises, in order from the object side of the lens to the modulator side of the lens, a first lens group having a positive power, including a positive lens element, a second lens group including a negative meniscus element having a concave surface toward the modulator side, a third lens group having a positive refractive power including a positive lens element or a positive and negative lens element, a fourth lens group including a negative lens element, a fifth lens group including a positive lens element, and a sixth lens group including a positive lens element.

Abstract: A lens system for reading images, consisting of six lens elements of positive, positive, negative, negative, positive and positive refractive power, respectively, in order from the object side, with a stop positioned between the third lens element and the fourth lens element. The first lens element L1 and the second lens element L2 each has a convex surface on the object side. The third lens element L3 has a concave surface on the image side, and the fourth lens element L4 has a concave surface on the object side. A fifth lens element L5 and a sixth lens element L6 each has a convex surface on the image side. At least one of the two pairs of lens elements L2, L3, and L4, L5 are coupled together, and specified conditions are satisfied in order to provide a lens having high resolution for color images.

Abstract: A wide-angle lens is disclosed having only three lens groups of negative, positive, and positive refractive power, in order from the object side, and having only six lens elements with refractive power. The first lens group is formed of a meniscus lens with its convex surface on the object side, the second lens group is formed of a biconvex lens, and the third lens group is formed of, in order from the object side, a biconcave lens element, a positive lens element having a convex surface on the image side, a positive lens element having a convex surface on the image side, and a positive lens element having a convex surface on the object side. A diaphragm is arranged between the second lens group and the third lens group. Furthermore, specified conditions are satisfied in order to provide a compact wide-angle lens that is well corrected for aberrations and has a sufficient back focal length to insert additional optical components.

Abstract: When a projection lens system used for a rear projection type image display apparatus has a first lens group having an aspherical lens surface, a second lens group, a third lens group sharing almost all the positive refractive power of the overall system, a fourth lens group having an aspherical lens surface, a fifth lens group, and a sixth lens group including a lens having a profile of aspherical surface in which the concave surface thereof faces the screen side and the refractive power in the marginal area is weaker than the refractive power around the optical axis, a projection lens system having a large aperture ratio (low F-number), high focus, wide field angle, and sufficient marginal light amount ratio can be realized at a low cost. When a predetermined opening portion is formed in the projection lens and lens barrel, the lens elements are cooled by air suction and exhaust and the lowering of the lens performance due to temperature change can be prevented.

Abstract: A Gaussian lens for photography includes, in order from the object side, a front lens group, a stop, and a rear lens group. The front lens group is formed of, in order from the object side, a first lens element and a second lens element, each of positive meniscus shape with their convex surfaces on the object side, and a third lens element that has a negative meniscus shape with its convex surface on the object side. The rear lens group is formed of, in order from the object side, a fourth lens element which has a negative meniscus shape with its concave surface on the object side, and fifth and sixth lens elements each of which is a positive meniscus lens with its convex surface on the image side. Each lens element surface is spaced from any adjacent lens elements so that no lens element surfaces are joined to form a combined lens.

Abstract: A Gaussian lens having no more than six lens elements of refractive power is formed of, in order from the object side: a first lens element which is biconvex, a second lens element which is a positive meniscus lens with its convex surface on the object side, a third lens element which is biconcave, a stop, a joined lens formed of a fourth lens element which is biconcave that is joined to a fifth lens element which is biconvex; and a sixth lens element having positive refractive power. Specified conditions are satisfied in order to provide a compact lens having an f-number FNO of 1.44 or less, an image angle 2&ohgr; of 23.8 degrees or more, and wherein the various aberrations are favorably corrected. The Gaussian lens of the invention is intended for mounting in monitor cameras.

Abstract: A photographic lens comprising: a front lens group and a rear lens group that are arranged in order from the object side; wherein the front lens group comprises, in order from the object side, a first lens element which is a positive meniscus lens having a convex surface facing the object side, a second lens element which is a positive meniscus lens having a convex surface facing the object side, and a third lens element that is cemented to the second lens element, the third lens element being a negative meniscus lens having a convex surface facing the object side; wherein said rear lens group comprises, in order from the object side, a fourth lens element which is a positive meniscus lens having a convex surface facing the image side; a fifth lens element which is a negative meniscus lens having a concave surface facing the object side; a sixth lens element that is cemented to the fifth lens element, the sixth lens element being a positive meniscus lens having a convex surface facing the image side; and wher

Abstract: By satisfying certain specified conditions, a projection lens having six lens groups and a low F-number of 1.4 is disclosed wherein a maximum angle between a principal ray and the optical axis on the reducing side of the projection lens is 2.5.degree. or less. This enables the projection lens to be used with a display which must be illuminated by light that is orthogonal to a display surface (as is the case with a liquid crystal display) without significant loss of light at the periphery of the image. Further, the projection lens can have its aberrations favorably corrected and be compact.

Abstract: A high-resolution objective for large-format photography has a pair of positive meniscuses flanking a stop area forming a lens aperture; and a respective negative cemented doublet on a side of each meniscus turned away from the stop area, the positive meniscuses being composed of glass having anomalous partial dispersion, a refractive index n.sub.e <1.63 and a dispersion or Abbe number .nu..sub.e >63, the cemented doublets each having a negative lens element and a positive lens element, the negative lens element being composed of a lead-free, arsenic-free and antimony-free glass with an anomalous dispersion, a refractive index n.sub.e >1.63 and an Abbe number .nu..sub.e <50.

Abstract: Projection-optical systems are disclosed for projecting an image of a first object M onto a second object P. Each such projection-optical system comprises, in order from the first-object side: a positive first lens group; a negative second lens group comprising a pair of negative lens elements forming a pair of concave surfaces facing each other; a positive third lens group comprising a lens element, positioned nearest the second object within the third lens group, having a concave surface facing the second object; an aperture stop; a positive fourth lens group comprising a lens element, positioned nearest the first object within the fourth lens group, having a concave surface facing the first object; a negative fifth lens group comprising a pair of negative lens elements that form a pair of concave surfaces facing each other; and a positive sixth lens group. The projection-optical systems satisfy any of several quantitative conditions.

Abstract: Six-component projection lens systems for use in projection televisions are provided. From the screen side, the systems preferably have a + - +++ - configuration. The use of a second lens element having a negative power results in improved sagittal modulation transfer functions (MTFs) at large field locations. The negative second lens element can be made of a low dispersion material, such as styrene, so as to provide partial correction of axial color.