Abstract: A compact optical imaging device with short optical length and low sensitivity, for use in an imaging module and an electronic device, comprises first to fifth lenses and a filter. An image-side surface of the fourth lens is convex near an optical axis of the optical imaging device. An image-side surface of the fifth lens is concave near the optical axis. The optical imaging device satisfies formulas 0.03 mm/°<TL5/FOV<0.1 mm/° and 2.4 mm<TL4/FNO<2.9 mm, TL5 being a distance from an object-side surface of the fifth lens to an image plane of the optical imaging device along the optical axis, FOV being a maximum field of view, TL4 being a distance from an object-side surface of the fourth lens to the image plane along the optical axis, and FNO being a F-number of the optical imaging device.

Abstract: A compact optical imaging device with short optical length and low sensitivity, for use in an imaging module and an electronic device, comprises first to fifth lenses and a filter. An image-side surface of the fourth lens is convex near an optical axis of the optical imaging device. An image-side surface of the fifth lens is concave near the optical axis. The optical imaging device satisfies formulas 0.03 mm/°<TL5/FOV<0.1 mm/° and 2.4 mm<TL4/FNO<2.9 mm, TL5 being a distance from an object-side surface of the fifth lens to an image plane of the optical imaging device along the optical axis, FOV being a maximum field of view, TL4 being a distance from an object-side surface of the fourth lens to the image plane along the optical axis, and FNO being a F-number of the optical imaging device.

Abstract: A headlight using an image light source is provided, which includes a laser light source and a wavelength converter. The laser light source includes multiple light-emitting units arranged in an array to provide an image beam. The wavelength converter is arranged downstream of an optical path of the laser light source. The wavelength converter is provided with a light dot matrix with the number of rows and columns greater than or equal to 40×40 to excite a part of the image beam into an excitation beam, and an unexcited part of the image beam is mixed with the excitation beam to generate a white beam.

Abstract: An optical imaging lens group, from an object side to an image side sequentially includes: a meniscus-shaped first lens having a negative refractive power and a convex surface facing the object side; a meniscus-shaped second lens having a negative refractive power and a convex surface facing the image side; an aperture stop; a third lens having a positive refractive power and two convex surfaces respectively at the object side and the image side; a fourth lens having a positive refractive power and two convex surfaces respectively at the object side and the image side; a fifth lens having a negative refractive power and two concave surfaces respectively at the object side and the image side; a sixth lens having a positive refractive power and two convex surfaces respectively at the object side and the image side; and a filter.

Abstract: An optical imaging lens includes a first lens element to a sixth lens element. The third lens element has negative refracting power and a periphery region of the image-side surface of the third lens element is convex. An optical axis region of the image-side surface of the fourth lens element is convex, an optical axis region of the image-side surface of the fifth lens element is convex, and an optical axis region of the object-side surface of the sixth lens element is concave to satisfy ?2+?3+?4+?6?130.000 and (T1+T4+G45)/(G12+T2+G34)?2.500.

Abstract: An optical imaging system includes a first lens, a second lens, a third lens, a fourth lens, a fifth lens, and a sixth lens, sequentially disposed from an object side. The first lens has negative refractive power, an image side surface thereof is concave, and an angle of view of the optical system including the first lens to the sixth lens is 100° or more. When a focal length of the first lens is f1_1, and a total focal length of the optical system including the first lens to the sixth lens is F1, 1.0<|f1_1/F1|<2.0 is satisfied.

Abstract: The present disclosure discloses a camera optical lens. The camera optical lens including, in an order from an object side to an image side, a first lens, a second lens, a third lens, a fourth lens, a fifth lens, and a sixth lens. The first lens is made of plastic material, the second lens is made of glass material, the third lens is made of plastic material, the fourth lens is made of glass material, the fifth lens is made of plastic material, and the sixth lens is made of plastic material. The camera optical lens further satisfies specific conditions.

Abstract: An optical imaging lens has six lens elements. A periphery region of the image-side surface of the first lens element is concave, an periphery region of the object-side surface of the third lens element is concave, an optical axis region of the object-side surface of the sixth lens element is concave, a periphery region of the object-side surface of the sixth lens element is convex, an optical axis region of the image-side surface of the sixth lens element is concave and a periphery region of the image-side surface of the sixth lens element is convex. AAG is a sum of five air gaps, T6 is a thickness of the sixth lens element and the Abbe number of the second, the third, the fourth, the fifth is ?2, ?3, ?4 and ?5 to satisfy ?2+?3+?4+?5?135.000 and AAG/T6?2.900.

Abstract: A lens assembly includes a first lens, a second lens, a third lens, a fourth lens, and a fifth lens, wherein the first lens, the second lens, the third lens, the fourth lens, and the fifth lens are arranged in order from an object side to an image side along an optical axis. The first lens is with positive refractive power and includes a concave surface facing the image side. The second lens is with positive refractive power and includes a concave surface facing the object side. The third lens is with negative refractive power. The fourth lens is with positive refractive power. The fifth lens is with negative refractive power. The lens assembly satisfies: f3+f4>0 mm, wherein f3 is an effective focal length of the third lens and f4 is an effective focal length of the fourth lens.

Abstract: An endoscope objective optical system consists of in order from an object side, a front group having a negative refractive power, an aperture stop, and a rear group having a positive refractive power, wherein either the front group or the rear group includes one or more than one cemented lens, and the cemented lens includes a lens having a positive refractive power and a lens having a negative refractive power, and the rear group includes a positive lens which is a single lens, on the object side, and the following conditional expressions (1), (2), (3), and (4) are satisfied. 1.1<Ih/ft<1.8??(1) ?ff/ft<0.9??(2) 45<?d1??(3) LOs/Ih<1.

Abstract: The present disclosure discloses a camera optical lens. The camera optical lens including, in an order from an object side to an image side, a first lens, a second lens having a positive refractive power, a third lens having a negative refractive power, a fourth lens, a fifth lens, and a sixth lens. The first lens is made of plastic material, the second lens is made of glass material, the third lens is made of plastic material, the fourth lens is made of plastic material, the fifth lens is made of plastic material, and the sixth lens is made of plastic material. The camera optical lens further satisfies specific conditions.

Abstract: The present disclosure discloses a camera optical lens. The camera optical lens including, in an order from an object side to an image side, a first lens, a second lens having a negative refractive power, a third lens having a positive refractive power, a fourth lens, a fifth lens, and a sixth lens. The camera optical lens further satisfies specific conditions.

Abstract: The present disclosure discloses a camera optical lens. The camera optical lens including, in an order from an object side to an image side, a first lens, a second lens having a positive refractive power, a third lens having a negative refractive power, a fourth lens, a fifth lens, and a sixth lens. The first lens is made of plastic material, the second lens is made of glass material, the third lens is made of plastic material, the fourth lens is made of plastic material, the fifth lens is made of plastic material, and the sixth lens is made of glass material. The camera optical lens further satisfies specific conditions.

Abstract: The present disclosure discloses a camera optical lens. The camera optical lens including, in an order from an object side to an image side, a first lens, a second lens having a negative refractive power, a third lens having a positive refractive power, a fourth lens, a fifth lens, and a sixth lens. The first lens is made of plastic material, the second lens is made of glass material, the third lens is made of plastic material, the fourth lens is made of glass material, the fifth lens is made of plastic material, and the sixth lens is made of plastic material. The camera optical lens further satisfies specific conditions.

Abstract: The present disclosure discloses a camera optical lens. The camera optical lens including, in an order from an object side to an image side, a first lens, a second lens, a third lens, a fourth lens, a fifth lens, and a sixth lens. The first lens is made of plastic material, the second lens is made of plastic material, the third lens is made of plastic material, the fourth lens is made of plastic material, the fifth lens is made of glass material, and the sixth lens is made of glass material. The camera optical lens further satisfies specific conditions.

Abstract: The present disclosure discloses a camera optical lens. The camera optical lens including, in an order from an object side to an image side, a first lens, a second lens having a positive refractive power, a third lens having a negative refractive power, a fourth lens, a fifth lens, and a sixth lens. The first lens is made of plastic material, the second lens is made of plastic material, the third lens is made of glass material, the fourth lens is made of plastic material, the fifth lens is made of glass material, and the sixth lens is made of plastic material. The camera optical lens further satisfies specific conditions.

Abstract: A large filed achromatic lens is disclosed, including 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 arranged sequentially along the propagation direction of an incident ray. The first lens element is a meniscus lens element including a first curved surface and a second curved surface; the second lens element is a meniscus lens element, including a third curved surface and a fourth curved surface; the third lens element is a biconvex lens element, including a fifth curved surface and a sixth curved surface; the fourth lens element is a biconvex lens element, including a seventh curved surface and an eighth curved surface; the fifth lens element is a biconcave lens element including a ninth curved surface and a tenth curved surface; and the sixth lens element is a plane lens element adapted to play a role in protecting other lens elements.

Abstract: An imaging lens is formed from six lenses, including a negative first lens having a concave surface toward the object side, a positive second lens, a negative third lens, a negative fourth lens of a meniscus shape with a concave surface toward the object side, a fifth lens, and a sixth lens having a concave surface toward the image side. The surface toward the image side thereof has an aspherical shape having at least one inflection point thereon, provided in this order from the object side.

Abstract: An imaging lens substantially consists of six lenses of a negative first lens, a negative second lens, a positive third lens, a positive fourth lens, a negative fifth lens and a positive sixth lens in this order from an object side. When a curvature radius of an object-side surface of the fourth lens is R8, and a curvature radius of an image-side surface of the fourth lens is R9, and an Abbe number of the material of the third lens for d-line is ?d3, and an Abbe number of the material of the fifth lens for d-line is ?d5, the following conditional formulas (1) and (6) are satisfied: ?0.61<(R8+R9)/(R8?R9)<0.44??(1); and 38.1<?d3+?d5<45.1??(6).

Abstract: An optical imaging lens assembly includes, in order from the object side to the 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 in a paraxial region. The fourth lens element with negative refractive power has a concave object-side surface in a paraxial region. The fifth lens element with positive refractive power has a convex image-side surface in a paraxial region. The sixth lens element with negative refractive power has a concave object-side surface in a paraxial region, a concave image-side surface in a paraxial region and at least one convex shape in the off-axial region of the image-side surface of the sixth lens element. The fifth lens element and the sixth lens element are aspheric lens elements.

Abstract: An imaging lens substantially consists of six lenses consisting of, in order from the object side: a first lens having a biconvex shape; a second lens having a negative refractive power; a third lens having a positive refractive power; a fourth lens having a positive refractive power; a fifth lens having a negative refractive power and having a concave surface toward the object side; and a sixth lens having a negative refractive power and having a concave surface toward the object side.

Abstract: An imaging 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 image-side surface. The second lens element has refractive power. The third lens element has refractive power. The fourth lens element has refractive power. The fifth lens element has negative refractive power. The sixth lens element with negative refractive power has a concave image-side surface in a paraxial region thereof, wherein both of the surfaces thereof are aspheric, and at least one of the surfaces thereof has at least one inflection point. The imaging lens assembly has a total of six lens elements with refractive power.

Abstract: An imaging lens system includes six non-cemented 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, a fourth lens element, a fifth lens element and a sixth lens element. The first lens element has positive refractive power. The second lens element has refractive power. The third lens element has positive refractive power. The fourth lens element has refractive power. The fifth lens element has refractive power, wherein both of the surfaces thereof are aspheric. The sixth lens element with refractive power has a concave image-side surface in a paraxial region thereof, wherein the image-side surface has at least one convex shape in an off-axis region thereof, and both of the surfaces thereof are aspheric. The imaging lens system has a total of six lens elements with refractive power.

Abstract: There is provided a lens module including: a first lens having refractive power and having a shape in which an image-side surface is concave; a second lens having refractive power; a third lens having positive refractive power; a fourth lens having positive refractive power; a fifth lens having negative refractive power; and a sixth lens having refractive power and having a point of inflection formed on an image-side surface thereof.

Abstract: Present embodiments provide for a mobile device and an optical imaging lens thereof. The optical imaging lens comprises six lens elements positioned sequentially from an object side to an image side. Through controlling the convex or concave shape of the surfaces and/or the refracting power of the lens elements, the optical imaging lens shows better optical characteristics and the total length of the optical imaging lens is shortened.

Abstract: Present embodiments provide for a mobile device and an optical imaging lens thereof. The optical imaging lens comprises six lens elements positioned sequentially from an object side to an image side. Through controlling the convex or concave shape of the surfaces and/or the refracting power of the lens elements, the optical imaging lens shows better optical characteristics and the total length of the optical imaging lens is shortened.

Abstract: An image pickup lens includes: in recited order from object plane toward image plane, a first lens having positive refractive power; a second lens having negative refractive power; a third lens having positive refractive power; a fourth lens having positive or negative refractive power; a fifth lens having positive refractive power; and a sixth lens having negative refractive power and having optical surfaces, one or more of the optical surfaces each having an aspherical shape with one or more inflection points.

Abstract: A zoom lens includes in order from an object side, a first lens group having a positive refractive power, a second lens group having a negative refractive power, a third lens group having a negative refractive power, a fourth lens group having a positive refractive power, a fifth lens group having a positive refractive power, and a last lens group having a positive refractive power. At the time of zooming from a wide angle end to a telephoto end, the second lens group and the third lens group move, and one of the fourth lens group, the fifth lens group, and the last lens group moves.

Abstract: A six-piece optical lens system includes, in order from the object side to the image side: a stop; a first lens element with a positive refractive power having a convex object-side surface; a second lens element with a negative refractive power having a concave image-side surface; a third lens element with a negative refractive power having a convex object-side surface; a fourth lens element with a positive refractive power having a convex image-side surface; a fifth lens element with a negative refractive power having a concave image-side surface; a sixth lens element with a negative refractive power having a concave object-side surface, each of the first, second, third, fourth, fifth and sixth lens elements has at least one aspheric surface. Thereby, such a system can be applied to a high resolution mobile phone, and has a wide field of view, big stop, high pixel, high resolution and low height.

Abstract: An imaging lens substantially consists of six lenses of a negative first lens, a negative second lens, a positive third lens, a positive fourth lens, a negative fifth lens and a positive sixth lens in this order from an object side. An object-side surface of the second lens has a shape having negative refractive power at a center, and including a part having positive refractive power in an area between the center and an effective diameter edge, and having negative refractive power at the effective diameter edge (concave shape facing the object side), and the refractive power at the effective diameter edge being weaker than the refractive power at the center. Further, an object-side surface of the third lens is convex toward the object side. Further, a predetermined conditional formula about a combined focal length of the first lens, the second lens and the third lens is satisfied.

Abstract: A six-piece optical lens system comprises, in order from the object side to the image side: a first lens element with a positive refractive power having a convex object-side surface; a second lens element with a negative refractive power having a concave image-side surface; a third lens element with a negative refractive power; a fourth lens element with a positive refractive power having a concave object-side surface; a fifth lens element with a positive refractive power having a convex image-side surface; a sixth lens element with a negative refractive power having a concave image-side surface, each of the first, second, third, fourth, fifth and sixth lens elements has at least one aspheric surface. Thereby, such a system not only can be applied to a high resolution mobile phone, but also has a wide field of view, big stop, high pixel, high resolution and low height.

Abstract: An image-capturing lens has, in order from an object, an object side lens group G1 and an image side lens group G2 which is disposed next to the object side lens group G1 with an air space, and focusing is performed from a distant object to a close object by moving at least a part of the image side lens group G2 along an optical axis as a focusing lens group, and image stabilization is performed by moving at least a part of the image side lens group G2 as a shift lens group so as to have components roughly orthogonal to the optical axis.

Abstract: An image 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 second lens element has refractive power. The third lens element has positive refractive power. The fourth lens element has negative refractive power. The fifth lens element with positive refractive power has a convex object-side surface and a concave image-side surface. The sixth lens element with positive refractive power has a convex object-side surface and a concave image-side surface, wherein the image-side surface thereof changes from concave at a paraxial region to convex at a peripheral region. The fifth and sixth lens elements are made of plastic, and the surfaces thereof are aspheric.

Abstract: An optical image collecting system 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 second through sixth lens elements all have refractive power. The fifth lens element has a concave object-side surface and a convex image-side surface, wherein at least one of the object-side surface and the image-side surface of the fifth lens element is aspheric. The sixth lens element has a concave image-side surface at a paraxial region, wherein the image-side surface of the sixth lens element changes from concave at the paraxial region to convex at a peripheral region, and both of an object-side surface and the image-side surface of the sixth lens element are aspheric.

Abstract: The present invention provides a mobile device and an optical imaging lens thereof. The optical imaging lens comprises six lens elements positioned in an order from an object side to an image side along an optical axis. Through controlling the convex or concave shape of the surfaces and/or the refracting power of the lens elements, the optical imaging lens shows better optical characteristics and the total length of the optical imaging lens is shortened.

Abstract: A zoom lens includes first to third lens units having positive, negative, and positive refractive power, respectively, and a rear lens group having positive refractive power. An aperture stop is arranged between a lens surface of the second lens unit closest to the image side and a lens surface of the third lens unit closest to the image side. The third lens unit includes first and second positive lenses each including an aspheric surface, and a negative lens. In the third lens unit, a refractive index of the first positive lens, and an Abbe number and relative partial dispersion of the second positive lens are appropriately set.

Abstract: A photographing 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 positive first lens element has a convex object-side surface. The second and the third lens elements have refractive power. The fourth lens element has positive refractive power. The negative fifth lens element has a convex object-side surface, a concave image-side surface, and at least one inflection point on at least one surface thereof, wherein the surfaces of the fifth lens element are aspheric. The negative sixth lens element has a concave image-side surface and at least one inflection point on at least one surface thereof, wherein the surfaces of the sixth lens element are aspheric. The photographing lens assembly has a total of six lens elements with refractive power.

Abstract: An imaging lens includes a first lens having positive refractive power; a second lens having negative refractive power; a third lens; a fourth lens having negative refractive power; a fifth lens having positive refractive power; and a sixth lens, arranged in this order from an object side to an image plane side. The first lens is formed so that a surface thereof on the object side has a positive curvature radius. The second lens is formed so that a surface thereof on the image plane side has a positive curvature radius. The fifth lens is formed so that a surface thereof on the object side and a surface thereof on the image plane side have negative curvature radii. Each of the third lens, the fourth lens, the fifth lens, and the sixth lens has refractive power weaker than that of each of the first lens and the second lens.

Abstract: An imaging lens includes a first lens having positive refractive power; a second lens having negative refractive power; a third lens having positive refractive power; a fourth lens having positive refractive power; a fifth lens having negative refractive power; and a sixth lens having negative refractive power. The first lens has an object-side with a positive curvature radius. The second lens has object-side and image plane-side surfaces with positive curvature radii. The third lens has an image plane-side surface with a negative curvature radius. The fourth lens has object-side and image plane-side surfaces with negative curvature radii. The fifth lens has object-side and image plane-side surfaces with negative curvature radii. The sixth lens has strong positive refractive power close to a periphery, and an aspheric image plane-side surface having an inflexion point. The first to sixth lenses have specific Abbe's numbers to satisfy specific conditions.

Abstract: An optical system includes a first lens unit, an aperture stop, and a second lens unit having a positive refractive power. The first lens unit includes a first lens having a negative refractive power and a second lens having a positive refractive power. The second lens unit includes a cemented lens, a fifth lens having a negative refractive power and a concave surface facing an object side, and a sixth lens having a positive refractive power and a convex surface facing an image side. In the cemented lens, a third lens having a positive refractive power and a fourth lens having a negative refractive power are cemented. A distance D1 from an object-side lens surface vertex of the first lens to the aperture stop and a distance Dt from the object-side lens surface vertex of the first lens to an image plane are appropriately set.

Abstract: An imaging lens substantially consisting of six lenses, composed of a first lens having a positive refractive power and a convex surface on the object side, a second lens having a negative refractive power and a concave surface on the image side, a third lens having a positive refractive power and a convex surface on the object side, a fourth lens having a positive refractive power, a fifth lens having a negative refractive power and a concave surface on the image side, and a sixth lens having a negative refractive power with the image side surface having an aspherical shape which is concave on the image side near the optical axis and convex in a peripheral region.

Abstract: An imaging 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 negative refractive power has a convex object-side surface and a concave image-side surface. The second lens element has positive refractive power. The third lens element has refractive power. The fourth lens element with refractive power has an object-side surface and an image-side surface being aspheric. The fifth lens element with positive refractive power has an object-side surface and an image-side surface being aspheric. The sixth lens element with negative refractive power has a concave image-side surface, wherein at least one reflection point is formed on the image-side surface thereof.

Abstract: An optical image system includes, in order from an object side to an image side, the first lens element with positive refractive power having a convex object-side surface; the second lens element with refractive power; the third lens element with positive refractive power having at least one surface being aspheric; the fourth lens element with refractive power having a concave object-side surface and a convex image-side surface, wherein at least one surface thereof element is aspheric; the fifth lens element with positive refractive power having a convex image-side surface; and the sixth lens element with negative refractive power made of plastic material and having a concave image-side surface, wherein at least one surface thereof is aspheric, and the image-side surface thereof changes from concave at a paraxial region to convex at a peripheral region.

Abstract: The invention is directed to correcting compound lens forms for 3rd and 5th order ray aberrations. All lens design forms have limiting aberrations. The proposed classes of lenses can be corrected for all 3rd and 5th order ray aberrations. The limiting aberrations are seventh order or higher. A variety of these lenses are disclosed here for the sake of example. These lens design forms can be used in various applications including the objective lens for an endoscope or other optical instrument.

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: ??g F>0.025. The third lens unit is manufactured from a material whose deviation of the relative partial dispersion fulfills the condition: ??g F<?0.0015. The fifth lens unit is manufactured from a material whose deviation of the relative partial dispersion fulfills the condition: ??g F<?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: An F-theta objective which is color-corrected for a wavelength range of 1065-1075 nm and is suitable for high laser outputs of more than 1 kW, having sixth individual lenses L1-L6, wherein the lenses are formed of at least two different materials.

Abstract: A first lens unit performing communication with an image pickup apparatus with a first voltage and a second lens unit performing communication with the image pickup apparatus with a second voltage are selectively attached to the image pickup apparatus. The image pickup apparatus includes a controller configured to operate with a third voltage different from at least one of the first and second voltages to output a signal for the communication with the first and second lens units, and a determiner configured to determine the type of the lens unit attached to the image pickup apparatus. The controller is configured to produce, as a voltage of the signal for the communication, from the third voltage, one of the first and second voltages corresponding to a determination result of the determiner.

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

Abstract: An endoscope objective lens unit includes a front lens group and a rear lens group with a diaphragm interposed therebetween. The front lens group includes a first lens and a second lens, and the rear lens group includes a third lens, a fourth lens and a fifth lens. The endoscope objective lens unit satisfies following expressions (1A) to (4): (1A) ?3 <SF ?1; (2) ?3 <Fr/Ff <?1.1; (3) ?1.6 <Ff/f <?0.6; and (4) Ff/f1 <1.6, where SF is a shape factor, Ff is a focal length of the front lens group, Fr is a focal length of the rear lens group, f is a focal length of the entire unit, and f1 is a focal length of the first lens.

Abstract: A fixed focal length lens including a first lens group, a second lens group, and a third lens group arranged in sequence from a magnified side towards a reduced side is provided. The first lens group has a positive refractive power, and includes a first lens and a second lens arranged in sequence from the magnified side towards the reduced side. Refractive powers of the first lens and the second lens are respectively negative and positive. The second lens group has a positive refractive power, and includes a third lens, a fourth lens, and a fifth lens arranged in sequence from the magnified side towards the reduced side. Refractive powers of the third lens, the fourth lens, and the fifth lens are respectively positive, negative, and positive. The third lens group has a positive refractive power, and includes a sixth lens. A refractive power of the sixth lens is positive.