123results about How to "Small F number" patented technology

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

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

Disclosed is an imaging lens having a small F number, a wide angle of view, and a low manufacturing cost and capable of obtaining a high-quality image.An imaging lens includes a first lens having a negative power and including a concave surface facing an image side, a second lens having a positive power, an aperture diaphragm, a third lens having a negative power, an aperture diaphragm, a fourth lens having a positive power, a fifth lens having a positive power and including a convex surface facing the image side, and a sixth lens having a negative power arranged in this order from an object side. When the curvature radius of an image-side surface of the third lens is R3r and the curvature radius of an object-side surface of the fourth lens is R4f, the imaging lens satisfies the following Conditional expression:|R3r / R4f|<1.0.

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

Disclosed is an imaging lens having a small F number, a wide angle of view, and a low manufacturing cost and capable of obtaining a high-quality image. An imaging lens includes a first lens having a negative power and including a concave surface facing an image side, a second lens having a positive power, an aperture diaphragm, a third lens having a negative power, an aperture diaphragm, a fourth lens having a positive power, a fifth lens having a positive power and including a convex surface facing the image side, and a sixth lens having a negative power arranged in this order from an object side. When the curvature radius of an image-side surface of the third lens is R3r and the curvature radius of an object-side surface of the fourth lens is R4f, the imaging lens satisfies the following Conditional expression:|R3r / R4f|<1.0.

The invention relates to a high-image-quality and low-distortion machine vision ultraviolet lens. The high-image-quality and low-distortion machine vision ultraviolet lens mainly comprises a front lens group, a rear lens group and a diaphragm, wherein each of the front lens group and the rear lens group has positive focal power; the diaphragm is positioned between the front lens group and the rear lens group; the front lens group is sequentially provided with a first lens, a second lens, a third lens and a fourth lens from an object space to an image space; the first lens, the second lens, the third lens and the fourth lens form a bonding lens; each of the first lens, the second lens and the third lens has negative focal power, and the four lens has the positive focal power; the rear lens group is sequentially provided with a fifth lens, a sixth lens, a seventh lens and an eighth lens from the object space to the image space; each of the fifth lens and the sixth lens has the positive focal power, and each of the seventh lens and the eighth lens has the negative focal power. With the eight spherical lenses, the high-image-quality and low-distortion machine vision ultraviolet lens has the characteristics of small F number, compact structure, low distortion, high resolution and the like, and is quite suitable for being integrated to a machine vision system.

A comparatively low f-number, compact two-group zoom optical system that corrects aberrations in the visible and the near-infrared regions includes, in order from the object side, a first lens group of negative refractive power and a second lens group of positive refractive power. The first lens group includes three lens components that are lens elements of negative, negative, negative, and positive refractive power, respectively, in order from the object side. The second lens group includes four lens components that are lens elements of positive, positive, negative, and positive refractive power, respectively, in order from the object side. Aspheric surfaces are disclosed. Certain conditions relating to the focal lengths of the two lens groups, indexes of refraction and Abbe numbers of various lens elements, and radii of curvature of an interior lens element of the second lens group are satisfied to control aberrations in both the visible and the near-infrared regions.

The invention relates to a medium wave infrared continuous zooming optical system with high zoom ratio, belongs to the technical field of optic lens, and aims to solve the existent problems of long zooming stroke, large F value and more lens in the prior art. The system comprises a front fixing group, a lens A of a time changing group, a lens C of a compensation group, a lens B of the time changing group, a lens D of the compensation group, a back fixing group, a secondary image formation group and a probe, coaxially arranged from left to right in sequence, wherein the continuous zooming of the system is realized through the axial movement of the time changing group and the compensation group. Through adopting the structure that the lens A and the lens B of the time changing group and the lens C and the lens D of the compensation group are arranged in a crossing manner to move, the continuous zooming is realized, the zooming stroke is short, the curve is smooth, 100% cold light stop efficiency is satisfied, the F value is constant to be 2, the continuous zooming can be carried out within the range of 10 mm to 300 mm of focal distance, and the image formation quality is sound in the whole focal distance range.

The invention provides an optical system for a miniaturization high-precision star sensor. According to the invention, a quasi-gauss lens structure is adopted and formed by 6 lenses; all the lenses are spherical lenses; and the glass of the first lens is made of fused quartz materials so that the first lens can be immediately used for correcting image difference and can be used as protection glass of the optical system. According to the optical system is characterized by wide spectrum, large view side and large relative aperture and has quite small distortion quantity in a quite wide spectrum range and view field; the concentration degree of confusion disc energy of each view field is uniformly distributed; the imaging quality is good; the system can work at a temperature from -50 DEG C to +70 DEG C and has good image quality and defocusing amount; and posture measurement of high-precision star sensor working in severe space and temperature can be met.

An optical lens system having a small F number, a wide angle of view, a short total length and a low manufacturing cost, includes, in order from an object side to an image side: a stop; a first lens element with a positive refractive power; a meniscus second lens element with a negative refractive power; a third lens element with a positive refractive power; a fourth lens element with a positive refractive power; a fifth lens element with a negative refractive power, the optical lens system has a focal length of f, the first lens element has a focal length f1, the third lens element has a focal length f3, the fourth lens element has a focal length f4, the fifth lens element has a focal length f5, and they satisfy the conditions: 0.4<f4 / f<1.0; −0.8<f5 / f<−0.4; and f1 / f<1.2<f3 / f.

An illuminating system and method for improving asymmetric projection includes a light source producing a light beam to form a light path, a projection lens disposed in the light path, a light valve inserted in the light path between the light source and the projection lens, and at least one anamorphic surface unit placed in the light path between the light source and the light valve. The anamorphic surface unit offsets a distortion of a light spot resulted from obliquely incidence on the light valve, thus an asymmetric light spot can be improved as a more symmetric one to increase illuminating collection efficiency and uniformity.

An off-axial three-mirror optical system with freeform surfaces includes a primary mirror, a secondary mirror, a tertiary mirror, and a detector. The primary mirror is located on an incident light path. The secondary mirror is located on a primary mirror reflecting light path. The tertiary mirror is located on a secondary mirror reflecting light path. The detector is located on a tertiary mirror reflecting light path. Each of the primary mirror, the secondary mirror, and the tertiary mirror is an xy polynomial freeform surface up to the fifth order.

The invention relates to a free-form surface off-axis three-reflector image-space telecentric optical system. The system includes a primary reflector, a secondary reflector, a third reflector and an image sensor; the primary reflector is used for reflecting light sent by an object space so as to obtain first reflected light; the secondary reflector is used for performing secondary reflection on the first reflected light to obtain second reflected light; the third reflector is used for reflecting the second reflected light again so as to obtain third reflected light; and the image sensor is used for receiving the third reflected light and performing imaging; the reflection surface of the primary reflector is a quartic polynomial free-form surface; and the reflection surfaces of the secondary reflector and the third reflector are both sextic polynomial free-form surfaces. According to the system, an obstruction-eliminated off-axis reflective structure is adopted, and an image-space telecentric effect can be approximately realized.

A fixed-focus lens including a first lens, a second lens, a cemented lens, an aperture stop, and a fifth lens is provided. The first lens disposed between an object side and an image side has a negative refractive power. The second lens disposed between the first lens and the image side has a positive refractive power. The cemented lens is disposed between the second lens and the image side. The cemented lens consists of a third lens and a fourth lens arranged in sequence from the object side to the image side. One of the third lens and the fourth lens has a positive refractive power, and the other has a negative refractive power. The aperture stop is disposed between the fourth lens and the image side. The fifth lens disposed between the aperture stop and the image side has a positive refractive power.

A wide-angle projection lens includes a first lens group with negative refractive power, a second lens group with positive refractive power and a third lens group with positive refractive power, all of which are arranged in order from a projection side to an image source side along an optical axis. The third lens group includes a first lens, a second lens, a third lens, a fourth lens, a fifth lens and a sixth lens, all of which are arranged in order from the projection side to the image source side along the optical axis, wherein the third lens and the fourth lens are cemented together to form a cemented lens and there is no air gap between the third lens and the fourth lens.

An image pickup lens includes a first lens with positive refractive power having a convex object side surface, an aperture stop, a second lens with negative refractive power having a convex image side surface, a third lens with positive refractive power having a concave image side surface, a fourth lens with positive refractive power having a convex image side surface, and a fifth lens with negative refractive power as a double-sided aspheric lens having a concave image side surface near the optical axis;wherein the first lens and the second lens satisfy following conditional expressions (1) and (2);50<ν1<85  (1)20<ν2<35  (2)where ν1 represents an Abbe number of the first lens, and ν2 represents an Abbe number of the second lens, and where the second lens satisfies a following conditional expression (3);1.55<Nd2<1.70  (3)where Nd2 represents a refractive index of d-ray of the second lens.

An imaging lens consists of a front group and a rear group. The front group is composed of a lens having a negative meniscus shape with a convex surface on the object side, a negative lens, a negative lens, and a positive lens in order from the object side. The rear group is composed of a positive lens, a negative lens, a positive lens, and a positive lens in order from the object side. The imaging lens satisfies given conditional expressions.

An imaging lens includes: a first lens with a meniscus shape having a concave surface facing an object side; a second positive lens; a third negative lens with a meniscus shape having a convex surface facing an image side; and a fourth negative lens. The first to fourth lenses are arranged in this order from the object side. The imaging lens is configured such that a normal line of an object-side surface of the fourth lens at a point where the outermost light beam of an on-axis light flux passes intersects the optical axis on the image side of the object-side surface.