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

Disclosed is an imaging lens having a small F-number, high resolution, a sufficiently wide angle of view, and a small size.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 lens having a convex surface facing the object side. The first to fourth lenses are arranged in this order from the object side. The imaging lens satisfies the following conditional expression:0.25<D / f<4.0(where D indicates the distance between the first lens and the second lens on the optical axis and f indicates the focal length of the entire system).

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.

Disclosed is an imaging lens having a small F-number, high resolution, a sufficiently wide angle of view, and a small size.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.

A slim lens assembly includes a first lens, a second lens, a third lens, a fourth lens and a fifth lens, all of which are arranged in sequence from an object side to an image side along an optical axis. The first lens is a convex-concave lens with negative refractive power and includes a convex surface facing the object side and a concave surface facing the image side. The second lens is with positive refractive power. The third lens is a biconcave lens with negative refractive power. The fourth lens is a biconvex lens with positive refractive power. The fifth lens is a convex-concave lens with negative refractive power and includes a convex surface facing the object side and a concave surface facing the image side.

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.

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)

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.

A variable magnification optical system includes a positive first lens group, a negative second lens group, a stop, a positive third lens group and a positive fourth lens group, which are in this order from an object side. The first lens group, the stop and the third lens group are fixed, but the second lens group and the fourth lens group move in an optical axis direction during magnification change. The fourth lens group has a focusing function. The third lens group includes at least an aspherical surface, and consists of, in the following order from the object side, a positive lens and a cemented lens of a positive lens and a double-concave lens cemented together. The variable magnification optical system satisfies a predetermined formula.

In constructing a lens for projection substantially consisting of seven lenses, and the reduction side of which is telecentric, a first-lens-group is composed of two lenses including at least one negative lens. A second-lens-group is composed of a positive second-group first-lens having a convex surface facing the magnification side, a negative second-group second-lens having a concave surface facing the magnification side, a positive second-group third-lens having a convex surface facing the reduction side, a positive second-group fourth-lens, and a positive second-group fifth-lens in this order from the magnification side. The formulas (A) and (B) are satisfied:1.2≦Bf / f≦2.5  (A);andf23 / f≦1.5  (B),whereBf is a back focus in air of an entire lens system,f is the focal length of the entire lens system, andf23 is the focal length of an air lens between a reduction-side surface of the second-group second-lens and a magnification-side surface of the second-group third-lens.

A lens for projection substantially consists of a negative first lens group, a positive second lens group and a positive third lens group in this order from a magnification side. A reduction side is telecentric, and a most magnification-side lens is an aspheric plastic lens. The third lens group consists of a negative front group and a positive rear group in this order from the magnification side with an air space therebetween. The front group consists of a negative lens and a positive lens in this order from the magnification side with an air space therebetween, and the air space being narrower than the air space between the front group and the rear group. Conditional formula (1): −0.7<fFG3 / f<0.7 about front focus fFG3 of the third lens group and focal length f of an entire system is satisfied.

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.

A negative first lens having a concave surface facing the reduction side of a lens for projection, a positive second lens having a convex surface facing the magnification side of the lens for projection, a negative third lens having a concave surface facing the magnification side, a positive fourth lens having a convex surface facing the reduction side, a positive fifth lens, and a positive sixth lens are arranged in this order from the magnification side, and the reduction side of the optical system is telecentric. Further, the following formula (A) is satisfied:1.2≦Bf / f≦2.5  (A), whereBf: back focus in air of the entire lens system of the lens for projection, andf: focal length of the entire lens system.

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.

A zoom lens for projection includes a negative first lens group, a positive second lens group, a positive third lens group, and a positive fourth lens group, which are arranged from the magnification side of the zoom lens in the order mentioned above. The first lens group and the fourth lens group are fixed during zooming, but the second lens group and the third lens group move on optical axis Z of the zoom lens toward the magnification side, based on an operation for operating the zoom lens from wide end to tele end, in such a manner that a distance between the second lens group and the third lens group changes. Further, the following formula (1) is satisfied:17<FG3 / fw  (1), whereFG3 focal length of the third lens group, andfw: focal length of entire system at wide end.

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 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.

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.

A zoom lens consists of, in order from the object side, a positive first lens group, a negative second lens group, a negative third lens group, a negative fourth lens group, a positive fifth lens group, and a positive sixth lens group. The first lens group and the sixth lens group are fixed with respect to an image plane, and a distance between the first lens group and the second lens group increases, a distance between the second lens group and the third lens group changes, and a distance between the third lens group and the fourth lens group changes, and a distance between the fourth lens group and the fifth lens group changes, and a distance between the fifth lens group and the sixth lens group changes during magnification change from a wide angle end to a telephoto end.

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.

A lens for projection substantially consists of a negative first-lens having a concave surface facing the reduction side, a positive second-lens having a convex surface facing the magnification side, a negative third-lens having a concave surface facing the magnification side, a positive fourth-lens having a convex surface facing the reduction side, and a positive fifth-lens, arranged in this order from the magnification side. Further, the following formulas (A) through (D) are satisfied:1.2≦Bf / f≦2.5  (A);−3.0≦f3F / f≦−0.8  (B);1.4≦f5F / f5≦8.5  (C); and1.0≦d12 / f≦2.7  (D), whereBf is a back focus,f is the focal length of an entire lens system,f3F is the focal length of a magnification-side surface of the third-lens,f5F is the focal length of a magnification-side surface of the fifth-lens,f5 is the focal length of the fifth-lens, andd12 is an air space between the first-lens and the second-lens.