Abstract: An optical imaging system includes a first lens, a second lens, a third lens, and a fourth lens sequentially disposed from an object side toward an image side on an optical axis, and a reflecting member disposed closer to the object side, as compared to the first lens, and having a reflecting surface configured to change a path of light to be incident to the first to fourth lenses. The first to fourth lenses are disposed to be spaced apart from each other by a preset distance along the optical axis, and 1.3<TTL/BFL<3.5, where TTL is a distance from an object-side surface of the first lens to an imaging plane of an image sensor, and BFL is a distance from an image-side surface of the fourth lens to the imaging plane of the image sensor.

Abstract: A stereoscopic vision endoscope objective optical system includes, in order from an object side, a first lens group having a negative refractive power, a second lens group having a positive refractive power, and a rear-side lens group having a positive refractive power. The rear-side lens group includes a first rear group and a second rear group. The first lens group and the second lens group are disposed so that an optical axis of the second lens group coincides with an optical axis of the first lens group. The optical axis of the first lens group is located between an optical axis of the first rear group and an optical axis of the second rear group. Each of the first rear group and the second rear group includes a first sub group, an aperture stop, and a second sub group, and the first sub group includes a negative lens.

Abstract: This disclosure describes illumination assemblies operable to generate a patterned illumination that maintain high contrast over a wide temperature range. An implementation of the illumination assembly can include an array of monochromatic light sources positioned on an illumination plane, first and second optical elements, and an exit aperture. A chief ray of each light source within the array of monochromatic light sources can substantially converge at an exit aperture. In such implementations light generated by the array of monochromatic light sources can be used efficiently.

Abstract: An optical imaging system includes a first lens, a second lens, a third lens, and a fourth lens sequentially disposed from an object side toward an image side on an optical axis, and a reflecting member disposed closer to the object side, as compared to the first lens, and having a reflecting surface configured to change a path of light to be incident to the first to fourth lenses. The first to fourth lenses are disposed to be spaced apart from each other by a preset distance along the optical axis, and 1.3<TTL/BFL<3.5, where TTL is a distance from an object-side surface of the first lens to an imaging plane of an image sensor, and BFL is a distance from an image-side surface of the fourth lens to the imaging plane of the image sensor.

Abstract: The invention discloses a four-piece optical lens for capturing image and a four-piece optical module for capturing image. From an object side to an image side, the optical lenses along the optical axis comprises a first lens with refractive power, a second lens with refractive power, a third lens with refractive power, and a fourth lens with refractive power; and at least one of an image-side surface and object-side surface of each of the four lens elements are aspheric. The optical lens can increase aperture value and improve the image quality for use in compact cameras.

Abstract: The objective lens unit includes, a front lens group having a negative refractive power, a diaphragm, and a rear lens group having a positive refractive power, in order from an object side. The front lens group includes a negative lens having a concave surface facing an image surface side, and a positive lens having a convex surface facing the object side, and the rear lens group includes a positive lens having a convex surface facing the image surface side and a cemented lens in which a positive lens and a negative lens are cemented. The endoscope objective lens unit satisfies ?1.6<fF/fR<?1.2 and ?1.0<SF5<?0.5. fF and fR are the focal lengths of the front lens group and the rear lens group, SF5 is (R51+R52)/(R51?R52), and R51 and R52 are respectively the curvature radiuses of surfaces.

Abstract: The invention discloses a four-piece optical lens for capturing image and a four-piece optical module for capturing image. In order from an object side to an image side, the optical lens along the optical axis comprises a first lens with refractive power; a second lens with refractive power; a third lens with refractive power; and a fourth lens with refractive power; and at least one of the image-side surface and object-side surface of each of the four lens elements are aspheric. The optical lens can increase aperture value and improve the imagining quality for use in compact cameras.

Abstract: An electronic device includes at least one optical lens assembly. The optical lens assembly includes four lens elements, and the four lens elements are, in order from an outside to an inside, a first lens element, a second lens element, a third lens element and a fourth lens element. The first lens element has an outside surface being convex in a paraxial region thereof. The second lens element has an inside surface being convex in a paraxial region thereof. The fourth lens element has an inside surface being concave in a paraxial region thereof, wherein at least one of an outside surface and the inside surface of the fourth lens element includes at least one critical point in an off-axis region thereof.

Abstract: The present disclosure discloses a camera lens assembly. The camera lens assembly includes, sequentially along an optical axis from an object side to an image side: a first lens, a second lens, a third lens, and a fourth lens. The first lens has a negative refractive power. The third lens has a positive refractive power. The second lens and the fourth lens both have refractive powers. An object-side surface of the third lens is a convex surface, an image-side surface of the fourth lens is a concave surface, and a radius of curvature R5 of the object-side surface of the third lens and a radius of curvature R8 of the image-side surface of the fourth lens satisfy: 0.7<R5/R8<1.2.

Abstract: The present disclosure discloses an optical imaging system, the optical imaging system including sequentially, along an optical axis from an object side to an image side, a first lens, a second lens, a third lens and a fourth lens. The first lens has a positive refractive power or a negative refractive power, an object-side surface of the first lens is a concave surface, and an image-side surface of the first lens is a convex surface; both the second lens and the third lens have positive refractive powers; and the fourth lens has a positive refractive power or a negative refractive power, wherein an abbe number V1 of the first lens and an abbe number V4 of the fourth lens satisfy: |V1?V4|?30; and the abbe number V1 of the first lens and an abbe number V2 of the second lens satisfy: 20?|V1?V2|?50.

Abstract: An optical system includes an optical element made of resin and a reflection portion configured to reflect ultraviolet radiation. The reflection portion is provided on an optical surface located closer to an object side than the optical element, and conditional expressions 0.10?Lu/L?0.90 and |tan?1(H0/Lr)?tan?1{H0(Lr?Lu)/(Ru×Lr)}|?25° are satisfied, in which H0 represents a maximum height, from an optical axis, of an optical surface closest to the object side, Lu represents a distance from the optical surface closest to the object side to the reflection portion, Lr represents a distance from the optical surface closest to the object side to the optical element, L represents a total length of the optical system, and Ru represents a radius of curvature of the optical surface on which the reflection portion is provided.

Abstract: A telecentric lens including a first lens group, an aperture stop, and a second lens group arranged in order from a magnified side to a minified side is provided. The first lens group has an outmost lens facing the magnified side, and the second lens group has an outmost lens facing the minified side. At least one of the outmost lens of the first lens group and the outmost lens of the second lens group is formed of glass. At least one of the first lens group and the second lens group has a lens having negative refractive power and being composed of plurality of lenses being mutually contacted to each other. The condition: TTL<100 mm is satisfied, wherein TTL denotes a length measured along an optical axis and between two outmost opposite lens surfaces of the telecentric lens.

Abstract: An imaging lens includes a first lens having negative refractive power; a second lens having positive refractive power; a third lens having positive refractive power; and a fourth lens, arranged in this order from an object side to an image plane side. The second lens is arranged to face the third lens. The first lens has a focal length f1 and the fourth lens has an Abbe's number ?d4 so that the specific conditional expressions are satisfied.

Abstract: An imaging lens includes first to fourth lens elements arranged from an object side to an image side in the given order. Through designs of surfaces of the lens elements and relevant lens parameters, a short system length of the imaging lens may be achieved while maintaining good optical performance.

Abstract: A miniature image pickup lens includes a first lens, a second lens, an aperture, a third lens, a fourth lens, and a fifth lens in sequence along an optical axis from an object side to an image side. The first lens is a negative meniscus lens with a convex aspheric surface toward the object side and a concave aspheric surface toward the image side. The second lens has both aspheric surfaces including a convex surface toward the object side. The third lens is a positive biconvex lens. The fourth lens is a positive biconvex lens. The fifth lens is a negative lens with a concave surface toward the object side.

Abstract: Provided is a zoom lens in which a variation in aberration with respect to a temperature change is small and excellent optical characteristics can be easily obtained. The zoom lens includes multiple lens units in which a distance between adjacent ones of the multiple lens units changes for zooming. When an average value of a change in refractive index with respect to a temperature change within a temperature range of from 0° C. to 40° C. is ?Nav, at least one lens unit L of the multiple lens units includes multiple optical elements A made of materials satisfying a conditional expression: |?Nav|>5.0×10?5. When an anomalous partial dispersion ratio for a g-line and an F-line is ??gF??, at least one optical element A? of the multiple optical elements A satisfies a conditional expression: |??gF??|>0.0272.

Abstract: An imaging lens includes negative first lens, negative second lens, third lens of a plano-convex shape having a convex surface directed toward an object side or of a positive meniscus shape having a convex surface directed toward the object side, and a fourth lens of a plano-convex shape having a convex surface directed toward an image side or of a positive meniscus shape having a convex surface directed toward the image side, which are arranged in this order from the object side. Further, the following conditional formula (6) is satisfied: 0.75?(R8?R9)/(R8+R9)?1.0??(6), where R8: a curvature radius of an object-side surface of the fourth lens, and R9: a curvature radius of an image-side surface of the fourth lens.

Abstract: An imaging lens provided with a negative first lens group and a positive second lens group disposed in order from the object side. The first lens group is composed of a first group first lens which is a negative biconcave single lens, and the second lens group is composed of a positive second group first lens, an aperture stop, a positive second group second lens, and a negative second group third lens disposed in order from the object side. The second group second lens and second group third lens are cemented together to form a cemented lens. The imaging lens is configured to satisfy a conditional expression (3) 0.9<dt3/f<1.3, and further configured to satisfy conditional expression (1) 31<?d2<55 or (1?): 35<?d2 and a conditional expression (2): ?10<?d1??d2<25.

Abstract: An imaging lens consists of a negative first lens, a negative second lens, a third lens of a plano-convex shape having a convex surface directed toward an object side or of a positive meniscus shape having a convex surface directed toward the object side, and a fourth lens of a plano-convex shape having a convex surface directed toward an image side or of a positive meniscus shape having a convex surface directed toward the image side, which are arranged in this order from the object side. Further, the following conditional formula (1) is satisfied: 2.25<?d2/?d3??(1), where ?d2: an Abbe number of a material of the second lens for d-line, and ?d3: an Abbe number of a material of the third lens for d-line.

Abstract: An imaging lens includes a first lens group having negative refractive power; a stop; and a second lens group having positive refractive power, arranged in the order from the object side to the image plane side. The first lens group includes a first lens having a strong concave surface facing the image plane side and negative refractive power; and a second lens having negative refractive power and a biconcave lens shape near the optical axis. The second lens group includes a third lens having a biconvex shape; and a lens group that is composed of a lens having positive refractive power and a lens having negative refractive power, and has negative refractive power as a whole. The first lens group has a focal length F1 and the second lens group has a focal length F2 so that the following conditional expression is satisfied: ?1.0<F1/F2<?0.5.

Abstract: An imaging lens formed of 4 lenses, in which a negative first lens having a meniscus shape with a convex surface on the object side, a biconvex positive second lens, a negative third lens having a concave surface on the image side, and a positive fourth lens having a convex surface on the object side, arranged in order from the object side, and the imaging lens satisfies conditional expressions (1): L12/f<0.82; (2): 2.3<L12×R2F2/f2<10.0; (5): ?1.3<f1/f<?0.9; and (6): 48<v1 simultaneously, where, L12 is the air equivalent distance between the first lens and the second lens, f is the focal length of the entire lens system, R2F is the radius of curvature of the object side lens surface of the second lens, f1 is the focal length of the first lens, and v1 is the Abbe number of the first lens with respect to the d-line.

Abstract: A projector for projecting light onto a projection surface includes a first group (1) with a negative meniscus, a second group (2) with positive refractive power, a third group (3) with a single lens, a fourth group (4) with a lens with positive refractive power, and a field lens (5) with positive refractive power, such that the light passes through the projection objective from the fourth to the first group. In order to be provide a high image quality with a small number of optical components and the smallest dimensions, the projector is configured so the common focal width of the fourth group (4) and the field lens (5) is smaller than twice the image circle diameter (9) of the projection objective and the maximum free diameter (8) is smaller than the overall focal width, and in particular smaller than 0.8 times the overall focal width of the projection objective.

Abstract: An image capturing lens system includes, in order from an object side to an image side, a first lens element, a second lens element, a third lens element and a fourth lens element. The first lens element has refractive power. The second lens element with positive refractive power has a convex image-side surface in a paraxial region thereof. The third lens element with negative refractive power has a concave object-side surface in a paraxial region thereof and a convex image-side surface in a paraxial region thereof. The fourth lens element with refractive power has a concave image-side surface in a paraxial region thereof, wherein both of an object-side surface and the image-side surface thereof are aspheric, and the image-side surface thereof has at least one convex shape in an off-axis region thereof. The image capturing lens system has a total of four lens elements with refractive power.

Abstract: A wide-angle image capturing lens assembly includes four lens elements with refractive power, in order from an object side to an image side, a first lens element, a second lens element, a third lens element and a fourth lens element and each of the first through fourth lens elements is single and non-cemented. The first lens element with negative refractive power has a concave image-side surface. The second lens element with refractive power has a concave object-side surface and a convex image-side surface. The third lens element with positive refractive power has a convex image-side surface. The fourth to lens element with negative refractive power has a concave object-side surface and a convex image-side surface, wherein both of the object-side surface and the image-side surface of the fourth lens element are aspheric.

Abstract: An imaging lens includes a negative first lens, a negative second lens, a third lens of a plano-convex shape having a convex surface directed toward an object side or of a positive meniscus shape having a convex surface directed toward the object side, and a fourth lens of a plano-convex shape having a convex surface directed toward an image side or of a positive meniscus shape having a convex surface directed toward the image side, which are arranged in this order from the object side. Further, the following conditional formula (4) is satisfied: 1.0<D2/f<2.5??(4), where f: a focal length of an entire system, and D2: a distance on an optical axis between the first lens and the second lens.

Abstract: An inner focus lens system comprises, in order from an object side to an image side, a first lens unit, an aperture stop, a second lens unit having a positive refractive power, a third lens unit having a negative refractive power, and a fourth lens unit having a positive refractive power. The first lens unit has at least one negative lens and at least one positive lens, the second lens unit has at least one negative lens and at least one positive lens, the third lens unit has at least one negative lens, and the fourth lens unit has at least one positive lens. When focusing on an object at a short distance from an object at infinity, the third lens unit moves to lengthen a distance to the second lens unit and to shorten a distance to the fourth lens unit.

Abstract: The endoscope objective lens is configured such that focusing from the farthest object to the nearest object is achieved by moving at least one lens group other than the most object-side lens group along the optical axis. One of the at least one lens group to be moved during focusing is a negative lens group. The one negative lens group that is moved during the focusing consists of a cemented lens that is formed by a positive lens and a negative lens cemented together in this order from the object side. The cemented surface of the cemented lens is oriented such that the concave surface faces the object side. Given conditional expressions are satisfied.

Abstract: An endoscope objective lens substantially consists of four lens groups consisting of, in order from the object side, a negative first lens group, a positive second lens group, a negative third lens group and a positive fourth lens group. During focusing from the farthest object to the nearest object, the first lens group is fixed, and the second lens group and the third lens group are moved along the optical axis. The third lens group includes a cemented lens that is formed by a positive lens and a negative lens cemented together in this order from the object side, and the cemented surface of the cemented lens is oriented such that the concave surface faces the object side.

Abstract: An imaging lens includes a first lens and a third lens having negative refractive power, and a second lens and a fourth lens having positive refractive power. Curvature radiuses of surfaces of the first lens on an object side and an image plane side are positive. A curvature radius of a surface of the second lens on the object side is positive. Curvature radiuses of surfaces of the third lens on the object side and the image plane side are negative. Curvature radiuses of surfaces of the fourth lens on the object side and the image plane side are positive. The first lens has a focal length f1 and the second lens has a focal length f2, so that the following conditional expression is satisfied: ?0.6<f2/f1<?0.1.

Abstract: An optical attachment configured to be operably attached to the image side of an objective lens to reduce the focal length and focal ratio of the objective lens. The focal-reducing attachment includes four lens elements and has a magnification of between 0.5 and 1. The focal-reducing lens can work with objective lenses having relatively large working distances for a large format size as well as with cameras having a smaller format size and relatively small permissible working distance.

Abstract: There is provided a zoom lens including in order from an object side to an image side, a first lens group having negative refractive power, a second lens group having positive refractive power, a third lens group having negative refractive power, and a fourth lens group having positive refractive power. In zooming from a wide-angle end to a telescopic end, the first lens group moves to the object side in a manner that a distance toward the second lens group narrows, and a distance between the third lens group and the fourth lens group widens. The third lens group includes a single lens or a single cemented lens.

Abstract: An imaging lens includes: a first lens group; a second lens group having positive refractive power; and a third lens group having negative refractive power, which are arranged in order from an object side, wherein the first lens group includes a former lens group having a negative lens in a most object side, a diaphragm, and a rear lens group, and wherein, when focusing is performed, the second lens group is moved in the optical axis direction.

Abstract: An image capturing lens assembly includes, in order from an object-side to an image-side along an optical axis, a first lens element, a second lens element, a third lens element and a fourth lens element. The first lens element with negative refractive power has an image-side surface being concave at a paraxial region. The second lens element with positive refractive power has an image-side surface being convex at a paraxial region. The third lens element with negative refractive power has an object-side surface being concave at a paraxial region, and an image-side surface being convex at a paraxial region. The fourth lens element with positive refractive power has an object-side surface being convex at a paraxial region, and an image-side surface being concave at a paraxial region, and at least one of the object-side surface and the image-side surface is aspheric.

Abstract: An endoscope objective lens substantially consists of four lens groups consisting of, in order from the object side, a negative first lens group, a positive second lens group, a negative third lens group and a positive fourth lens group. During focusing from the farthest object to the nearest object, the first lens group is fixed, and the second lens group and the third lens group are moved along the optical axis. The third lens group includes a cemented lens that is formed by a positive lens and a negative lens cemented together in this order from the object side, and the cemented surface of the cemented lens is oriented such that the concave surface faces the object side.

Abstract: An imaging lens includes a first lens having negative refractive power; a second lens having positive refractive power; a third lens having positive refractive power; and a fourth lens having negative refractive power, arranged from an object side to an image plane side. In the first lens, a curvature radius of an image-side surface is positive. In the second lens, curvature radii of the object-side surface and the image-side surface are both negative. In the third lens, a curvature radius of the object-side surface is positive and a curvature radius of the image-side surface is negative. When a whole lens system has a focal length f and the first lens has a focal length f1, the imaging lens satisfies the following conditional expression: ?3.0<f1/f<?1.

Abstract: The angle of view of an objective optical system is widened, while suppressing generation of lateral chromatic aberration. An objective optical system includes: a first lens group having a negative power; an aperture stop; and a second lens group having a positive power, in this order from an object side. The first lens group includes a negative single first lens, and a cemented lens formed by cementing a positive lens and a negative lens together, provided in this order from the object side. The second lens group includes a positive single fourth lens, and a cemented lens formed by cementing a positive lens and a negative lens together, provided in this order from the object side. The objective optical system satisfies Conditional Formula (1): 15.0<?d(RN)<18.6, wherein ?d(RN) is the Abbe's number of the negative lens in the cemented lens within the second lens group with respect to the d line.

Abstract: An objective optical system includes: a negative first lens group; an aperture stop; and a positive second lens group, provided in this order from an object side. The first lens group includes a first lens, which is a negative single lens, and a cemented lens formed by cementing a positive lens and a negative lens together, provided in this order from the object side. The second lens group includes a fourth lens, which is a positive single lens, and a cemented lens formed by cementing a positive lens and a negative lens together, provided in this order from the object side. The objective optical system satisfies Conditional Formula (1): f1/f<1.1, wherein f1 is the focal length of the lens provided most toward the object side, and f is the focal length of the entire lens system.

Abstract: An objective optical system includes: a first lens group having a negative power; an aperture stop; and a second lens group having a positive power, provided in this order from an object side. The first lens group includes a first lens, which is a negative single lens, and a cemented lens formed by a positive lens and a negative lens, provided in this order from the object side. The second lens group includes a fourth lens, which is a positive single lens, and a cemented lens formed by a positive lens and a negative lens, provided in this order from the object side. The objective optical system simultaneously satisfies Conditional Formulae (1) ?1.5<f123/f<?0.5 and (2) 1.8<f456/f<2.1, wherein f is the focal length of the entire system, f123 is the combined focal system of the first lens group, and f456 is the combined focal length of the second lens group.

Abstract: Disclosed herein is an imaging lens. The imaging lens according to a preferred embodiment of the present invention includes a first lens having positive (+) power and having both sides formed to be convex, a second lens having negative (?) power and formed to be concave toward a top side, a third lens having positive power and having both sides formed to be convex, a fourth lens having positive (+) power and formed to be convex toward a top side, and a fifth lens having negative (?) power and formed to be concave toward the top side, wherein the first lens, the second lens, the third lens, the fourth lens, and the fifth lens are disposed in order from an object side.

Abstract: A wide-angle image capturing lens assembly includes four lens elements with refractive power, in order from an object side to an image side, a first lens element, a second lens element, a third lens element and a fourth lens element and each of the first through fourth lens elements is single and non-cemented. The first lens element with negative refractive power has a concave image-side surface. The second lens element with refractive power has a concave object-side surface and a convex image-side surface. The third lens element with positive refractive power has a convex image-side surface. The fourth to lens element with negative refractive power has a concave object-side surface and a convex image-side surface, wherein both of the object-side surface and the image-side surface of the fourth lens element are aspheric.

Abstract: A zoom lens system comprising a negative first lens unit, a positive second lens unit, a negative third lens unit, and a positive fourth lens unit, wherein the second lens unit is composed of an object-side second lens unit and an image-side second lens unit, the object-side second lens unit has positive optical power, an aperture diaphragm is located between the object-side second lens unit and the image-side second lens unit, and the conditions: ?0.5<f2O/f2I<1.0 and 0.12<d2O/fW<0.35 (f2O: a composite focal length of the object-side second lens unit, f2I: a composite focal length of the image-side second lens unit, d2O: an optical axial distance from a most object side lens surface of the object-side second lens unit to the aperture diaphragm, fW: a focal length of the entire system at a wide-angle limit) are satisfied.

Abstract: An imaging lens includes a first lens having negative refractive power; a second lens having positive refractive power; a third lens having positive refractive power; and a fourth lens having negative refractive power, arranged from an object side to an image plane side. In the first lens, a curvature radius of an image-side surface is positive. In the second lens, curvature radii of the object-side surface and the image-side surface are both negative. In the third lens, a curvature radius of the object-side surface is positive and a curvature radius of the image-side surface is negative. When a whole lens system has a focal length f and the first lens has a focal length f1, the imaging lens satisfies the following conditional expression: ?3.0<f1/f<?1.

Abstract: An imaging lens consists of a negative first lens, a negative second lens, a third lens of a plano-convex shape having a convex surface directed toward an object side or of a positive meniscus shape having a convex surface directed toward the object side, and a fourth lens of a plano-convex shape having a convex surface directed toward an image side or of a positive meniscus shape having a convex surface directed toward the image side, which are arranged in this order from the object side. Further, the following conditional formula (1) is satisfied: 2.25<?d2/?d3??(1), where ?d2: an Abbe number of a material of the second lens for d-line, and ?d3: an Abbe number of a material of the third lens for d-line.

Abstract: An optical system includes a negative lens unit including one or more negative lenses located closest to an object side, and a positive lens unit having positive refractive power including a plurality of lenses on an image side of the negative lens unit. When the one or more negative lenses are denoted by negative lenses LNi (i=1, 2, . . . ) in order from the object side, and a portion of lenses among the plurality of the lenses constituting the positive lens unit is denoted by lenses LAj (j=1, 2, . . . ) in order from the object side, a focal length fni of the negative lens LNi, a refractive index Nni of a material thereof, a focal length fAj of the lens LAj, a refractive index NAj, and partial dispersion ratio ?gFAj of a material of the lens LAj are set to satisfy respective predetermined conditions.

Abstract: A zoom lens includes, in order from an object side to an image side, a first lens unit of a negative refractive power, a second lens unit of a positive refractive power, and a third lens unit of a positive refractive power, an interval between the first lens unit and the second lens unit and an interval between the second lens unit and the third lens unit being configured to change in zooming from a wide angle end to a telephoto end. The first lens unit includes, in order from the object side to the image side, a negative lens and a positive lens. The predetermined conditions are satisfied.

Abstract: The present invention provides a wide-angle imaging lens assembly comprising, in order from an object side to an image side: a first lens element with negative refractive power having a convex object-side surface and a concave image-side surface; a second lens element with negative refractive power having a convex object-side surface and a concave image-side surface; a third lens element with positive refractive power; a fourth lens element with negative refractive power having a concave image-side surface; and a fifth lens element with positive refractive power; wherein the two lens elements with refractive power closest to the object side are the first lens element and the second lens element; and wherein the number of lens elements with refractive power does not exceed six.

Abstract: A Miniature zoom lens, in particular for use in mobile telephones, in which the zoom lens, as viewed from the object plane, has the following in the stated sequence: at least one negative first optical lens group, at least one negative second optical lens group, at least one positive third optical lens group, and at least one positive fourth optical lens group. The second, third, and fourth optical lens groups are configured in such a way that focusing is achieved solely by displacement of the fourth optical lens group, and during the focusing the positions of the second and third lens groups remain unchanged.

Abstract: An endoscope optical system, including a front group and a rear group arranged in this order from an object side such that an aperture stop is arranged between the front and rear groups, wherein the front group includes a negative lens and a positive lens arranged in this order from the object side, the rear group includes a positive lens and a cemented lens arranged in this order from the object side, and when f (unit: mm) denotes a focal length of an entire endoscope optical system, EX (unit: mm) denotes a distance (which takes a minus sign on the object side with respect to an image plane) from the image plane to an exit pupil, and f2 (unit: mm) denotes a focal length of the rear group, the endoscope optical system satisfies conditions: ?10<EX/f<?6??(1), and 1.15<f2/f<1.35??(2).

Abstract: An optical imaging lens assembly comprises, in order from an object side to an image side, a first lens element, a second lens element, a third lens element and a fourth lens element. There is a stop disposed between the first lens element and the third lens element. The first lens element has negative refractive power, the second lens element has positive refractive power, the third lens element has negative refractive power, and the fourth lens element has positive refractive power. The first lens element has a convex object-side surface and a concave image-side surface. The third lens element and the fourth lens element both have at least one of its object-side surface and its image-side surface being aspheric. With the aforementioned arrangement, the optical imaging lens assembly of the present invention can obtain a larger viewing angle, lower sensitivity and higher resolution.

Abstract: A projection lens consists of first and second les groups and a stop. The first lens group is formed of a negative lens. The second lens group is formed of three positive lenses and a negative lens. The stop is disposed between the first and second lens groups or in the second lens group. The first and second lens groups are arranged in order from a magnification side. The projection lens is telecentric on a reduction side. The projection lens is configured to satisfy the following conditional expressions (1) and (2): 1.0?f2h/f?5.0??(1) ?2.5?f1/f??0.8??(2) where f2h is a focal length of an aspheric lens of at least one of the first and second positive lenses of the second lens group, f is a focal length of the whole system, and f1 is a focal length of the first lens group.