Abstract: An optical imaging lens includes a first lens element, a second lens element, a third lens element, a fourth lens element, a fifth lens element, a sixth lens element, a seventh lens element, and an eighth lens element from an object side to an image side in order along an optical axis. The first lens element to the eighth lens element each include an object-side surface facing the object side and an image-side surface facing the image side. Lens elements of the optical imaging lens are only the first, second, third, fourth, fifth, sixth, seventh and eighth lens elements. The periphery region of the image-side surface of the first lens element is concave. The optical axis region of the image-side surface of the seventh lens element is concave, and the periphery region of the image-side surface of the seventh lens element is convex.

Abstract: An imaging lens system includes eight lens elements which are, 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, a sixth lens element, a seventh lens element and an eighth lens element. Each of the eight lens elements has an object-side surface facing toward the object side and an image-side surface facing toward the image side. At least one lens element of the imaging lens system has at least one lens surface having at least one inflection point. The imaging lens system has a total of eight lens elements.

Abstract: A wide-angle optical system includes a pair of front side lens units, an optical member, and a pair of rear side lens units. Each of the pair of front side lens units has a negative refractive power. The optical member has a pair of inclined surfaces and a bottom surface, and the pair of inclined surfaces is disposed such that a line of intersection is formed on an object side. Each of the pair of rear side lens units includes a positive lens, and in the pair of rear side lens units, two axes of rotational symmetry are parallel. With respect to two light rays, intersection and reflection occur at the optical member, and the intersection and the reflection occur after the two light rays are transmitted through the pair of inclined surfaces and before two light rays are transmitted through the bottom surface.

Abstract: The present disclosure relates to the technical field of optical lens and discloses a camera optical lens satisfying following conditions: 65.00?v1?90.00; ?5.00?f2/f??1.50; 1.50?(R5+R6)/(R5?R6)?30.00; and ?6.00?R12/R11??1.20; where v1 denotes an abbe number of the first lens L1; f denotes a focal length of the camera optical lens; f2 denotes a focal length of the second lens; R5 denotes a central curvature radius of an object-side surface of the third lens; R6 denotes a central curvature radius of an image-side surface of the third lens; R11 denotes a central curvature radius of an object-side surface of the sixth lens; and R12 denotes a central curvature radius of an image-side surface of the sixth lens. The camera optical lens provided in the present disclosure satisfies a design requirement of large aperture, wide angle and ultra-thinness while having good optical functions.

Abstract: A lens assembly including 4˜7 lenses with a refractive power is provided. D1 is the diameter of a lens surface farthest away from the image plane of the lens assembly. DL is the diameter of a lens surface closest to the image plane of the lens assembly. LT is the length on an optical axis of the lens from the lens surface farthest away from the image plane of the lens assembly to the lens surface closest to the image plane of the lens assembly. The lens assembly satisfies the following conditions: (1) 6 mm<DL<20 mm, 1.5<LT/DL<2.4 and D1/DL>0.6 or (2) 6 mm<DL<20 mm, 1.25<LT/DL<1.7 and D1/DL>0.4.

Abstract: A camera optical lens is provided. The camera optical lens includes, from an object side to an image side, a first lens, a second lens having a negative refractive power, a third lens, a fourth lens, a fifth lens, a sixth lens, a seventh lens, an eighth lens, and a ninth lens. The camera optical lens satisfies following conditions: 2.00?f1/f?5.50; and 2.00?d7/d8?10.00, where f denotes a focal length of the camera optical lens, f1 denotes a focal length of the first lens, d7 denotes an on-axis thickness of the fourth lens, and d8 denotes an on-axis distance from an image side surface of the fourth lens to an object side surface of the fifth lens. The camera optical lens according to the present disclosure satisfies design requirements for large-aperture, wide-angle, and ultra-thin lenses while achieving good optical performance.

Abstract: An imaging lens includes a first lens having positive refractive power; a second lens; a third lens; a fourth lens; a fifth lens; a sixth lens; a seventh lens; an eighth lens; and a ninth lens, arranged in this order from an object side to an image plane side. The imaging lens has a total of nine lenses. The eighth lens has at least one aspheric surface. The ninth lens is formed in a shape so that a surface thereof on the image plane side has an aspherical shape. The ninth lens is formed in the shape so that the surface thereof on the image plane side has a specific paraxial curvature radius.

Abstract: An imaging lens includes a first lens; a second lens; a third lens; a fourth lens; a fifth lens; a sixth lens; a seventh lens having positive refractive power; an eighth lens; and a ninth lens, arranged in this order from an object side to an image plane side. The imaging lens has a total of nine lenses. The eighth lens is formed in a shape so that a surface thereof on the object side has an aspherical shape. The ninth lens is formed in a shape so that a surface thereof on the image plane side has an aspherical shape.

Abstract: An optical imaging lens may include a first, a second, a third, a fourth, a fifth, a sixth, a seventh, and an eighth lens elements positioned in an order from an object side to an image side. Through designing concave and/or convex surfaces of each lens elements, the optical imaging lens may provide improved imaging quality and optical characteristics, reduced length of the optical imaging lens and increased field of view while the optical imaging lens may satisfy one of the third, fourth, fifth and sixth lens element is the lens element with the maximum thickness along the optical axis.

Abstract: An optical imaging lens assembly includes, in order from an object side to an image side: a first, a second, a third, a fourth, a fifth and a sixth lens elements. The first lens element has negative refractive power. The second lens element has an object-side surface being concave in a paraxial region thereof. The third lens element has an object-side surface being convex in a paraxial region thereof. The fifth lens element with negative refractive power has an object-side surface being concave and an image-side surface being convex in a paraxial region thereof. The sixth lens element has an image-side surface being concave in a paraxial region thereof. At least one of an object-side surface and the image-side surface of the sixth lens element has at least one critical point in an off-axis region thereof, wherein both the surfaces of the sixth lens element are aspheric.

Abstract: A ceramic substrate is formed of polycrystalline ceramic and has a supporting main surface. At the supporting main surface of the ceramic substrate, the mean of grain sizes of the polycrystalline ceramic is 15 ?m or more and less than 40 ?m and the standard deviation of the grain sizes is less than 1.5 times the mean.

Abstract: The present disclosure discloses an imaging lens assembly. The imaging lens assembly includes, sequentially from an object side to an image side of the imaging lens assembly, a first lens having a positive refractive power and a convex object-side surface; a second lens having a negative refractive power and a concave image-side surface; and at least one subsequent lens. At least one of the first lens, the second lens, or the at least one subsequent lens is a glass aspheric lens. A transmittance T1 of the imaging lens assembly corresponding to a wave band 650 nm satisfies: T1>85%, a transmittance T2 of the imaging lens assembly corresponding to a wave band 490 nm satisfies: T2>88%, and a transmittance T3 of the imaging lens assembly corresponding to a wave band 430 nm satisfies: T3>75%.

Abstract: An imaging lens includes a first lens; a second lens; a third lens; a fourth lens; a fifth lens; a sixth lens; a seventh lens; an eighth lens; and a ninth lens having negative refractive power, arranged in this order from an object side to an image plane side. The imaging lens has a total of nine lenses. The eighth lens has at least one aspheric surface. The ninth lens is formed in a shape so that a surface thereof on the image plane side has an aspherical shape. The ninth lens is formed in the shape so that the surface thereof on the image plane side has a specific paraxial curvature radius.

Abstract: An imaging lens includes a first lens having positive refractive power; a second lens; a third lens; a fourth lens; a fifth lens; a sixth lens; a seventh lens; an eighth lens; and a ninth lens, arranged in this order from an object side to an image plane side. The imaging lens has a total of nine lenses. The first lens is formed in a shape so that a surface thereof on the image plane side has an aspherical shape. The ninth lens is formed in a shape so that a surface thereof on the image plane side has an aspherical shape.

Abstract: An imaging lens includes a first lens; a second lens; a third lens; a fourth lens; a fifth lens; a sixth lens; a seventh lens; an eighth lens; and a ninth lens having negative refractive power, arranged in this order from an object side to an image plane side. The imaging lens has a total of nine lenses. The first lens is formed in a shape so that a surface thereof on the image plane side has an aspherical shape. The ninth lens is formed in a shape so that a surface thereof on the image plane side has an aspherical shape.

Abstract: An imaging lens includes a first lens; a second lens; a third lens; a fourth lens; a fifth lens having positive refractive power; a sixth lens; a seventh lens; an eighth lens; and a ninth lens, arranged in this order from an object side to an image plane side. The imaging lens has a total of nine lenses. The first lens has at least one aspheric surface. The ninth lens is formed in a shape so that a surface thereof on the image plane side has an aspherical shape. The ninth lens has a specific focal length.

Abstract: An imaging lens includes a first lens; a second lens; a third lens; a fourth lens; a fifth lens; a sixth lens; a seventh lens; an eighth lens having positive refractive power; and a ninth lens, arranged in this order from an object side an image plane side. The imaging lens has a total of nine lenses. The first lens is formed in a shape so that a surface thereof on the image plane side has an aspherical shape. The ninth lens is formed in a shape so that a surface thereof on the image plane side has an aspherical shape.

Abstract: The present invention provides a camera optical lens including, from an object side to an image side, a first lens, a second lens, a third lens, a third lens, a fourth lens, a fifth lens, a sixth lens, a seventh lens and a eighth lens. The first, third, fifth and seventh lens have positive refractive power, while the second, fourth, sixth and eighth lens have negative refractive power. The camera optical lens satisfies the following conditions: 0.70?f1/f?1.00; ?20.00?f4/f?3.50; and 2.30?f5/f?4.50; where f denotes a focal length of the camera optical lens, and f1, f4 and f5 respectively denote a focal length of the first lens, the fourth lens and the fifth lens. The camera optical lens in the present disclosure satisfies a design requirement of large aperture, wide angle and ultra-thinness while having good optical functions.

Abstract: The present invention provides a camera optical lens including, from an object side to an image side, a first lens having a positive refractive power, a second lens having a negative refractive power, a third lens, a fourth lens having a positive refractive power, a fifth lens having a negative refractive power, a sixth lens having a negative refractive power, a seventh lens having a positive refractive power and a eighth lens having a negative refractive power. The camera optical lens satisfies the following conditions: 0.65?f1/f?0.85, 2.00?f4/f?5.00, and ?5.50?f5/f??2.50; where f, f1, f4 and f5 respectively denote a focal length of the camera optical lens, the first lens, the fourth lens and the fifth lens. The camera optical lens in the present disclosure has characteristics of large aperture, wide angle and ultra-thinness while having good optical functions.

Abstract: An optical imaging system includes a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, a seventh lens, and an eighth lens, which are sequentially arranged from an object side optical imaging system. The first lens has positive refractive power and the second lens has positive refractive power. At least one of the lenses has negative refractive power with a refractive index greater than 1.68.

Abstract: An imaging lens includes a first lens; a second lens; a third lens; a fourth lens; a fifth lens; a sixth lens; and a seventh lens, arranged in this order from an object side to an image plane side. The first lens is formed in a meniscus shape at a paraxial region thereof. The third lens is formed in a shape so that a surface thereof directing to the image plane side is concave at a paraxial region thereof. The fourth lens is formed in a meniscus shape at a paraxial region thereof. The seventh lens has a specific focal length.

Abstract: An optical system including two optical systems, each optical system including at least two reflectors and a stop. Each of the optical systems is configured to focus light. Each of the at least two reflectors is configured to reflect the light.

Abstract: An optical imaging lens includes a first lens element, a second lens element, a third lens element, a fourth lens element, a fifth lens element, a sixth lens element, a seventh lens element, and an eighth lens element from an object side to an image side in order along an optical axis. The first lens element to the eighth lens element each include an object-side surface facing the object side and an image-side surface facing the image side. The periphery region of the image-side surface of the first lens element is concave. The optical axis region of the image-side surface of the third lens element is concave. The periphery region of the object-side surface of the fourth lens element is concave and the optical axis region of the image-side surface of the fourth lens element is convex. The optical axis region of the image-side surface of the seventh lens element is concave.

Abstract: An optical assembly for a point action camera or other compact digital camera having a wide field of view, includes multiple lens elements, including at least one lens element that has an aspheric lens surface. The optical assembly is configured to provide a field of view in excess of 120 degrees. The optical assembly includes a ratio of a diameter of a first lens element at the object end of the optical assembly to an image diagonal is less than approximately 3.

Abstract: A method for adjusting a specimen holder in the beam path of a microscope, in which at least one beam of an illumination radiation is directed onto the specimen holder; a component of the illumination radiation reflected by the specimen holder is captured by means of a detector and measurement values of the captured illumination radiation are ascertained. A current actual manner of positioning of the specimen holder in relation to the beam path is established depending on the measurement values; the established actual manner of positioning is compared to an intended manner of positioning, and control commands for modifying the actual manner of positioning are produced, the execution of which causes the specimen holder to be moved into the intended manner of positioning.

Abstract: An apparatus and method are disclosed to produce a stereoscopic image with a hemispherical field of view. In an implementation, the apparatus includes an optical arrangement to receive first light rays from a first fisheye lens and second light rays from a second fisheye lens. The first fisheye lens and the second fisheye lens are positioned adjacent to each other and an object side of each of the first and second fisheye lenses faces a first plane. The optical arrangement is to direct the first light rays and the second light rays onto an image sensor and bend optical axes of the first and second light rays such that the first light rays are projected onto the image sensor alongside the second light rays.

Abstract: An imaging lens system includes eight lens elements which are, 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, a sixth lens element, a seventh lens element and an eighth lens element. Each of the eight lens elements has an object-side surface facing toward the object side and an image-side surface facing toward the image side. At least one lens element of the imaging lens system has at least one lens surface having at least one inflection point. The imaging lens system has a total of eight lens elements.

Abstract: A laser apparatus including an optical element made of a CaF2 crystal and configured to transmit an ultraviolet laser beam obliquely incident on one surface of the optical element, the electric field axis of the P-polarized component of the laser beam propagating through the optical element coinciding with one axis contained in <111> of the CaF2 crystal, with the P-polarized component defined with respect to the one surface. A method for manufacturing an optical element, the method including causing a seed CaF2 crystal to undergo crystal growth along one axis contained in <111> to form an ingot, setting a cutting axis to be an axis inclining by an angle within 14.18±5° with respect to the crystal growth direction toward the direction of another axis contained in <111>, which differs from the crystal growth direction, and cutting the ingot along a plane perpendicular to the cutting axis.

Abstract: Provided is a silicone mold with which a curable composition containing an epoxy resin can be molded with good precision even if used repeatedly. The silicone mold according to an embodiment of the present invention is a silicone mold for use in molding a curable composition containing an epoxy resin, the silicone mold including a cured product of a silicone resin composition, wherein the cured product has a light transmittance at a wavelength of 400 nm of 80% or higher at a thickness of 1 mm, an elongation at break in accordance with JIS K 7161 of 250% or less, and a thermal linear expansion coefficient of 350 ppm/° C. or less at 20 to 40° C.

Abstract: A telephoto lens includes first, second and third lens units. The first lens unit has positive refractive power front-side lens, first rear-side lens, and second rear-side lens units. The first lens unit has a negative lens element satisfying 0.5?|f/fLn|?4.908. The third lens unit has positive and negative lens elements. The first rear-side lens unit includes a predetermined negative lens element and a positive lens element. Lens elements of the front-side lens unit include at least one positive lens element. The second rear-side lens unit has a positive lens element. Conditional Expression 0.247??GFGR1/f?0.5 is satisfied. f and fLn are focal lengths of the telephoto lens and predetermined negative lens element. ?GFGR1 is an axial distance from an object-side surface in the front-side lens unit to an object-side surface in the first rear-side lens unit.

Abstract: A laser optical device includes: an optical fiber unit for transmitting a laser beam; a connector for connecting the optical fiber unit; a collimator for transforming the laser beam into a parallel beam; and a condenser lens unit for condensing the parallel beam. The parallel beam emitted from the condenser lens unit is a flat-top beam. A laser optical head includes: a housing; a connector located in the housing and for connecting an optical fiber unit; a collimator formed at one side of the connector located in the housing and for transforming a laser beam transmitted from the optical fiber unit into a parallel beam; and a condenser lens unit located in the housing and for condensing the parallel beam. The parallel beam emitted from the condenser lens unit is a flat-top beam.

Abstract: An imaging device includes a casing, a plurality of optical systems disposed in the casing, a plurality of image sensors, disposed in the casing, for generating images captured by using the plurality of optical systems, a heat generation member disposed in the casing, and a pair of sandwiching members disposed in the casing to sandwich the heat generation member between the pair of members.

Abstract: An optical system (OL) used for an optical apparatus such as a camera (1) includes a focusing group (Gf) that moves upon focusing, a diffractive optical element (GD) disposed on an object side of the focusing group (Gf) and a negative lens element (L1n) disposed on the object side of the diffractive optical element (GD). The optical system (OL) satisfies the following expressions 0.030<f/fpf<0.050 nd1n+0.006×?d1n<1.910 35<?d1n where, f: focal length of whole system in infinity focusing state fpf: focal length of diffractive optical element (GD) nd1n: refractive index of medium of negative lens element (L1n) on d-line ?d1n: Abbe number of medium of negative lens element (L1n) on d-line.

Abstract: A projection optical system is for an image projection device. The projection optical system includes a whole lens system of seven to nine lenses and an aperture stop. The seven to nine lenses are all single lenses. One negative lens and one or two positive lenses are located on a magnifying side with respect to the aperture stop. Two negative lenses and three or four positive lenses are located on a reducing side with respect to the aperture stop. A lens adjacent to the magnifying side of the aperture stop and a lens adjacent to the reducing side of the aperture stop are both a negative lens.

Abstract: Provided is an optical system consisting of, in order from an object side to an image side, a front lens group (FLG), an aperture stop and a rear lens group (RLG), in which FLG includes at least one positive lens and at least one negative lens. A focal length of a positive lens Lp arranged closest to object side among the at least one positive lens, a focal length of a negative lens Ln arranged closest to image side among the at least one negative lens, a distance on an optical axis from an object-side lens surface of positive lens Lp to aperture stop, a distance on optical axis from an object-side lens surface of negative lens Ln to aperture stop, and a distance on optical axis from aperture stop to a lens surface closest to image side in RLG when focused at infinity are appropriately set.

Abstract: Provided is a curable composition which has excellent curability, less causes silicone molds to swell, and allows the silicone molds to have better durability and a longer service life in repeated use. The curable composition according to the present invention is a curable composition for production of an optical component by molding using silicone molds. The curable composition contains curable compounds and a cationic initiator. The curable compounds include (A) a cycloaliphatic epoxy compound and (B) an oxetane compound. The oxetane compound (B) is present in a content of 10 to 45 weight percent of the totality of all the curable compounds contained in the curable composition. Of the totality of all the curable compounds contained in the curable composition, 90 weight percent or more is a compound or compounds having a solubility parameter of 9.0 (cal/cm3)½ or more as determined at 25° C. by the Fedors' method.

Abstract: The present disclosure discloses an optical imaging lens assembly. The optical imaging lens assembly includes, sequentially along an optical axis from an object side to an image side, a first lens having a refractive power; a second lens having a positive refractive power; a third lens having a refractive power; a fourth lens having a refractive power; a fifth lens having a refractive power; a sixth lens having a refractive power; a seventh lens having a refractive power, wherein an image-side surface of the seventh lens is a convex surface; and an eighth lens having a refractive power. There is an air spacing between any two adjacent lenses in the first to eighth lenses. A total effective focal length f of the optical imaging lens assembly and an entrance pupil diameter EPD of the optical imaging lens assembly satisfy: f/EPD?2.0.

Abstract: An optical lens includes, in order along a direction, an aperture stop and a lens group with a positive refractive power. The aperture stop is disposed at an outermost side of all lenses of the optical lens, and the lens group has at least four lenses. At least one of the four lenses is an aspheric lens, and each of the four lenses has a clear aperture of smaller than 14 mm.

Abstract: A large-aperture, high-pixel optical system has six lenses arranged successively from its object side to its image side along its optic axis. The first lens has a convex surface facing the object side and a concave surface facing the image side; The third lens is biconcave; the second and fifth lenses are biconvex; the fourth and sixth lenses each have a concave surface facing the object side and a convex surface facing the image side. The fifth lens and the sixth lens form a combined lens and the optical system satisfies TTL/EFL?4.5. Also disclosed is a camera module using the system. The system and the module are mainly composed of six lenses. Since the number of lenses used is limited, the structure is simple.

Abstract: An imaging lens includes a front lens group, an aperture stop, and a rear lens group arranged in that order from an object side to an image side. An object-side lens closest to an object within the front lens group and an image-side lens closest to an image within the rear lens group are configured to form only three air lenses therebetween. The air lens is an air gap between an image-side surface of an object-side lens and an object-side surface of an image-side lens. The object-side lens and the image-side lens is adjacent to each other in an optical axis of the imaging lens. The three air lenses include an object-side air lens, an image-side air lens, and an intermediate air lens. The object-side air lens and the image-side air lens is biconvex, and the intermediate air lens is biconcave.

Abstract: A photographing optical 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, a fourth lens element, a fifth lens element, a sixth lens element, a seventh lens element and an eighth lens element. The second lens element has positive refractive power. The eighth lens element has an image-side surface being concave in a paraxial region thereof, wherein the image-side surface of the eighth lens element has at least one convex shape in an off-axis region thereof, and both an object-side surface and the image-side surface thereof are aspheric. The photographing optical lens system has a total of eight lens elements. An air gap in a paraxial region is located between every two lens elements of the photographing optical lens system that are adjacent to each other.

Abstract: A projection optical system satisfies ?1?15 (deg) and 3<EP/Ym<7. ?1 is a maximum inclination angle of the reflective surface of each of the micromirrors with respect to the line normal to the image display surface; EP is an entrance pupil distance of the projection optical system; and Ym is a maximum distance in a plane from an optical axis to a point on the image display surface, the plane being a plane in which a light ray propagating from a center of the image display surface toward the projection surface through a center of an aperture stop of the projection optical system exists, the optical axis being an axis shared by a largest number of the plurality of lenses of the projection optical system, the point corresponding to an image on the projection surface.

Abstract: Provided is a photographing lens optical system. The lens optical system includes a first lens, a second lens, a third lens, a fourth lens, and a fifth lens sequentially arranged from an object to an image sensor. The first lens may have a negative (?) refractive power and have an exit surface that is concave with respect to the image sensor. The lens optical system may satisfy at least one of a condition 100°<FOV<200° and a condition 1<TTL/ImgH<2. Herein, FOV denotes an angle of view of the lens optical system, TTL denotes a distance from an incidence surface of the first lens to the image sensor, and ImgH denotes a diagonal length of a maximum pixel region of the image sensor.

Abstract: The lens system forms an image conjugately between each of a magnification conjugate point and a reduction conjugate point; and an intermediate image-forming position. The lens system includes a magnification optical system with positive power, the magnification optical system having a plurality of lens elements and positioned closer to the magnification side than the intermediate image-forming position; and a relay optical system with positive power, the relay optical system having a plurality of lens elements and positioned closer to the reduction side than the intermediate image-forming position. The lens system satisfies following conditions (1) and (2). 0.08?fp/fr?0.8??(1) {Ymax?ft·tan(?max)}/{ft·tan(?max)}??0.3??(2) where fr is composite focal length of the relay optical system, fp is composite focal length of the magnification optical system, Ymax is a radius of an effective image diameter, ?max is a maximum half view angle, and ft is the focal length of the lens system.

Abstract: According to one embodiment, an optical test apparatus includes a first optical system, a second optical system, and an image sensor. The first optical system is configured to pass a light ray of a first wavelength and having telecentricity on an object side for the light ray of the first wavelength. The second optical system is configured to pass a light ray of a second wavelength different from the first wavelength. The image sensor is configured to image an object based on the light ray of the first wavelength having passed through the first optical system and the light ray of the second wavelength having passed through the second optical system.

Abstract: The present disclosure provides a camera lens, constituted by eight lenses, and featuring excellent optical characteristics, an ultra-thin appearance, a wide angle and a bright Fno. The camera lens is configured with, sequentially from an object side: a 1st lens having a positive refractive power, a 2nd lens having a negative refractive power, a 3rd lens having a negative refractive power, a 4th lens having a positive refractive power, a 5th lens having a negative refractive power, a 6th lens having a positive refractive power, a 7th lens having a positive refractive power and an 8th lens having a negative refractive power, and satisfies specified conditional formulas.

Abstract: An apparatus and method for controlling the spectrum of stimulated Raman scattering that is used for despeckling of digitally projected images. The stimulated Raman scattering is utilized to add wavelength diversity for reduced speckle and to change the color of the light to a more desirable combination of wavelengths. Digital projection with color-sequential projectors may be enabled by alternately switching the Raman spectrum between green and red. Improved projector transmission may be achieved by minimizing the amount of yellow light generated in the Raman spectrum.

Abstract: A lens unit includes: a lens in which first and second circular portions are arranged in an optical axis direction, the first circular portion having a first diameter, the second circular portion having a second diameter larger than the first diameter; a sealing member that is annular when viewed in the optical axis direction and that has an inner peripheral surface that contacts an outer peripheral surface of the first circular portion; and a lens barrel including first and second inner wall portions, the first inner wall portion being circular when viewed in the optical axis direction and pressing the sealing member between the first inner wall portion and the first circular portion, the second inner wall portion having three or more contact portions that contact an outer peripheral surface of the second circular portion and that are arranged with spaces therebetween in a circumferential direction of the lens.

Abstract: An optical imaging system includes a first lens comprising a positive refractive power, and a concave object-side surface, a second lens comprising a positive refractive power, a third lens comprising a negative refractive power, a fourth lens comprising a positive refractive power, and a fifth lens comprising a positive refractive power, a concave image-side surface. The first through fifth lenses are sequentially disposed from an object side toward an imaging plane.

Abstract: The imaging lens consists of, in order from the object side, a first lens group having a positive refractive power, a second lens group, and a third lens group. In the second lens group, a first focus lens group having a negative refractive power is disposed to be closest to the object side, and a second focus lens group having a positive refractive power is disposed to be closest to the image side. During focusing, only the first and second focus lens groups move by changing the mutual spacing therebetween. The first lens group has two positive lenses and one negative lens. The first focus lens group consists of two or less lenses including a negative lens. Predetermined conditional expressions are satisfied.