Abstract: An imaging optical system includes three lens elements. The three lens elements, in order from an object side to an image side, are a first lens element having an object-side surface facing the object side and an image-side surface facing the image side, a second lens element having an object-side surface facing the object side and an image-side surface facing the image side, and a third lens element having an object-side surface facing the object side and an image-side surface facing the image side. The third lens element has positive refractive power, the imaging optical system has a total of three lens elements, and there are air gaps between paraxial regions of the first lens element, the second lens element and the third lens element.

Abstract: The present disclosure relates to the field of optical lenses and provides a camera optical lens. The camera optical lens includes, from an object side to an image side: an aperture; a first lens having a positive refractive power; a second lens having a positive refractive power; a third lens having a negative refractive power; a fourth lens having a negative refractive power; a fifth lens having a positive refractive power; and a sixth lens having a negative refractive power. The camera optical lens satisfies following conditions: 8.00?d1/d2?12.00; and 2.80?v1/v3?4.00, where d1 denotes an on-axis thickness of the first lens; d2 denotes an on-axis distance from an image side surface of the first lens to an object side surface of the second lens; v1 denotes an abbe number of the first lens; and v3 denotes an abbe number of the third lens.

Abstract: An optical lens is provided with three lens pieces. The optical lens includes a diaphragm, a first lens piece having positive focal power, a second lens piece having negative focal power and a third lens piece having positive focal power, arranged in sequence. The first lens piece has an S1 surface and an S2 surface. The second lens piece has an S3 surface and an S4 surface. The third lens piece has an S5 surface and an S6 surface. An S7 surface is provided on a side of the S6 surface away from the S5 surface. A lens frame is provided at the S6 surface or between the S6 and S7 surfaces. The calibers of the Si to S7 surfaces sequentially decrease. An equivalent focal length of the first lens piece is larger than that of the third lens piece. A numerical aperture of the lens is larger than 0.6.

Abstract: The present invention provides a lens barrel applicable to digital cameras, image pickup devices and cell phones. The lens barrel is small, low-cost and high-performance, and can suppress, by means of a simple mechanism provided in the lens barrel, a variation in the focal position of the lens barrel caused by the change in temperature. The lens barrel comprises a lens group consisting of a plurality of lenses and a lens chamber for holding the lens group. An elastic member is provided between a set of adjacent lenses of the lens group, for urging the set of adjacent lenses in an optical axis direction of the lenses.

Abstract: A single-focal-length imaging lens system achieves focusing by, while keeping first and third lens groups stationary relative to the image plane, moving a second lens group along the optical axis. The second lens group includes a positive lens element. The third lens group includes an aspherically shaped lens element having an inflection point at a position other than the intersection with the optical axis. The first and second air lenses formed by the intervals between the first and second and between the second and third lens groups have negative and positive refractive powers respectively. The conditional formula 0?|Fi1/Fi2|?|Fm1/Fm2|?10 is fulfilled (Fi1 and Fi2 representing the focal lengths of the first and second air lenses, respectively, when focusing on the infinite object distance; Fm1 and Fm2 representing the focal lengths of the first and second air lenses, respectively, when focusing on the closest object distance).

Abstract: An imaging lens includes a first lens; a second lens; and a third lens arranged from an object side to an image plane side. The first lens has an object-side surface having a positive curvature radius R1f and an image plane-side surface having a negative curvature radius R1r. The second lens has an object-side surface and an image plane-side surface with negative curvature radii. The third lens has an object-side surface and an image plane-side surface with positive curvature radii and formed as aspheric surfaces having inflexion points. When the whole lens system has a focal length f, the first lens has a focal length f1, the second lens has a focal length f2, and the third lens has a focal length f3, the imaging lens satisfies the following conditional expressions: f1<f2<f3 1.0<f1/f<1.5 ?0.

Abstract: A far-infrared camera includes three lenses formed of ZnS. A first lens is a biconvex lens, a second lens is a negative meniscus or biconcave lens, and a third lens is a positive meniscus lens. A diffraction surface is formed in either surface of a lens. When a total focal distance f of the lens system is 10 mm to 30 mm and a focal distance f12 of the first and second lenses is 20 mm to 70 mm, 1?f12/f?3.

Abstract: A pickup lens is provided with various aberrations corrected satisfactorily, with a short optical length, and with a sufficient back focus secured. The configuration comprises an aperture diaphragm S1, first lens L1, second lens L2, and third lens L3, and is configured by arranging, in order from the object side to the image side, the aperture diaphragm, first lens, second lens, and third lens. The first lens is a lens having positive refractive power, in a meniscus shape with the convex surface on the object side. The second lens is a lens having negative refractive power, in a meniscus shape with the convex surface on the image side. The third lens is a lens having negative refractive power, in a meniscus shape with the convex surface on the object side. Both of the surfaces of the first lens are aspherical, both of the surfaces of the second lens are aspherical, and both of the surfaces of the third lens are aspherical.

Abstract: An optical lens system for taking image comprises three lens elements with refractive power, from the object side to the image side: a first lens element with positive refractive power having a convex object-side surface and a convex image-side surface, and the object-side surface being aspheric; a plastic second lens element with negative refractive power having a concave object-side surface and a convex image-side surface, and the front and image-side surfaces thereof being aspheric; a plastic third lens element with positive refractive power having a convex object-side surface and a concave image-side surface, the front and image-side surfaces thereof being aspheric; wherein an aperture stop is located between the first and second lens elements. By such arrangements, it can reduce the volume and sensitivity of the optical lens system, and furthermore can obtain higher resolution.

Abstract: A lens module (800) includes a lens barrel (20), a base (10), and a temperature compensation module (30). A first lens (201) is disposed in the lens barrel. The lens barrel is disposed in the base. The temperature compensation module is detachably installed in the base, and the temperature compensation module includes a temperature compensation lens (302). The temperature compensation lens is configured for compensating for deformation of the first lens caused by temperature changes.

Abstract: A lens that can be used in a digital camera includes in sequence a first lens element (20), a second lens element (30) and a third lens element (40). The first lens element is biconvex, and includes a first aspheric surface (22) and a second aspheric surface (24). The second lens is concavo-convex, and includes a third aspheric surface (32) and a fourth aspheric surface (34). The third lens includes a wavelike fifth aspheric surface (42) and a wavelike sixth aspheric surface (44). All of the lens elements are made of glass. The lens has a compact volume, and provides stable imaging performance and good image quality.

Abstract: The present invention includes, from an object side to an image-plane side: an aperture stop with a predetermined diameter, a first lens with a positive refractive power having a convex surface on the object side, a second lens with a positive refractive power having a concave surface on the object side, and a third lens with a negative refractive power having a convex surface on the object side. The second and third lenses have aspherical surfaces on their object-side and image-plane-side surfaces. The third lens is formed with an inflection point where the curvature orientation changes within the effective diameter range of the aspherical surface on the image-plane side. An appropriate back focus is maintained while the total length of the lens system is reduced.

Abstract: The object of the present invention is to provide a wide converter lens capable of obtaining an angle of view of about 80° or over and having small appearance of distortion. According to one aspect, a wide converter lens for using by attaching to an object side of a photographic lens includes, in order from the object side, a first positive lens having double convex surfaces, a negative lens unit including at least one negative lens, and a second positive lens having double convex surfaces. The following conditional expression is satisfied: −0.8<(r2+r1)/(r2−r1)<0.8 where r1 denotes the radius of curvature of the object side surface of the first positive lens and r2 denotes the radius of curvature of the image side surface of the first positive lens.

Abstract: In a three-lens configuration, the first lens is formed into a biconvex lens, the third lens is formed into a positive meniscus lens having a concave surface directed onto the object side, and the refractive index distribution of the refractive index distribution type second lens is defined by a predetermined conditional expression, whereby various kinds of aberration are made favorable even when used for reading out images at a magnification near 1:1, while achieving wider angle of view, higher performances, and compactness. An imaging lens for copying to be used at a magnification near 1:1 comprises the first lens L.sub.1 having a biconvex form, the second lens L.sub.2 having a biconcave form with a refractive index distribution along the optical axis direction, and the third lens L.sub.3 made of a positive meniscus lens having a concave surface directed onto the object side, whereas a stop i is disposed between the second lens L.sub.2 and the third lens L.sub.3. The refractive index of the second lens L.

Abstract: Disclosed is a telephoto-type lens system of a head separated charge coupled device (CCD) camera, which includes a first lens group having a positive focal length, a second lens group having a negative focal length, and a third lens group. The first lens group has a first convex lens surface facing an object and an upper convex surface. The third lens group has a second lens with a negative focal length joined to a first lens with a positive focal length. An image angle greater than 29.degree. and high definition images can be achieved with the present invention.

Abstract: A Cooke triplet projection lens for use in overhead projectors comprises two outer positive elements of an ophthalmic crown glass and one inner negative element of a light flint glass. The crown glass has a refractive index of roughly 1.523 and an Abbe value of 58.5. The flint has an index of less than 1.573 and an Abbe value of between 43 and 53. One of the positive elements is biconvex; the other is meniscus.

Abstract: A variable focus color corrected field lens for accepting rays having a divergence of from 0, wherein the rays are collimated, to a divergence of 10 milliradians full angle and directing the rays to the same point of an optical system. The present lens is corrected for wavelengths from the ultraviolet to the red spectrum of wavelengths for directing the wavelengths to the same point.