Abstract: A projection lens projecting an image beam provided by a light valve onto a screen is provided. The projection lens includes first to fourth lenses in order from a screen side to a display side along an optical axis. Each lens has a screen side surface facing the screen side and allowing the image beam to pass, and a display side surface facing the display side and allowing the image beam to pass. The first and third lenses have a negative refractive power, and the second and fourth lenses have a positive refractive power. The projection lens satisfies 2<TTL/f<5. TTL is a distance from the screen side surface of the first lens to the display side surface of the fourth lens on the optical axis. f is an effective focal length of the projection lens. The projection lens covers a wide range of operating temperatures while being lightweight.

Abstract: A 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 order from an object side to an image side along an optical axis. The first lens has negative refractive power. The second lens has positive refractive power. The third lens has positive refractive power. The fourth lens has negative refractive power including a convex surface facing the object side and a concave surface facing the image side. The fifth lens has negative refractive power including a concave surface facing the object side.

Abstract: A lithographic apparatus arranged to project a pattern from a patterning device onto a substrate, comprising at least one housing comprising at least one internal wall, at least one optical component arranged within at least one chamber defined at least in part by the at least one internal wall and configured to receive a radiation beam and a cooling apparatus arranged to cool at least a portion of the at least one internal wall to a temperature below that of the at least one optical component.

Abstract: The present disclosure provides a lens module, a camera, and a driver assistant system. From an object side to an image side, the lens module sequentially includes a first lens with a negative refractive power, a second lens with a negative refractive power, a third lens with a positive refractive power, a stop, a fourth lens with a positive refractive power, a fifth lens with a negative refractive power, a sixth lens with a positive refractive power, and a filter. The fifth lens and the fourth lens constitute a bonding lens group. The second lens, the third lens, the fourth lens, and the fifth lens are glass spherical lenses, and the first lens and the sixth lens are both glass aspherical lenses. The lens module significantly increases the distortion in a small FOV to meet the special algorithm requirements of an in-vehicle system.

Abstract: The invention consists of a fixed focal length objective lens forming an image of an object with a plurality of lens elements and an aperture stop (114), wherein the aperture stop (114) defines an aperture stop proximity space (118) and at least one field proximity space (120, 122). The objective lens comprises at least three aspherical surfaces (124, 126, 128, 130) of a lens element. Either two aspherical surfaces (128, 130) are positioned in the aperture stop proximity space (118) and at least one aspherical surface (124, 126) is positioned in a field proximity space (120, 122). Or at least one aspherical surface (128, 130) is positioned in the aperture stop proximity space (118) and two aspherical surfaces (124, 126) are positioned in a field proximity space (120, 122). This distribution of aspherical surfaces provides for means of optimally correction aberrations leading to a very high level of aberration correction.

Abstract: An optical device, having at least first and second light-transmitting substrates, each having at least two external surfaces and an input aperture and an output aperture. The external surface of the first light-transmitting substrate is optically cemented to an external surface of the second light-transmitting substrate by an optical adhesive defining an interface plane. The refractive index of the optical adhesive is substantially lower than the refractive index of the first substrate. Part of the light waves entering the device through the input aperture and exiting the device through the output aperture impinge on the interface plane of the first substrate having incidence angles smaller than the critical angle. Another part of the light waves impinging on the interface plane have incidence angles higher than the critical angle. The interface plane is substantially transparent for the light waves impinging on interface plane having incidence angles smaller than the critical angle.

Abstract: This disclosure describes illumination assemblies operable to generate a patterned illumination that maintain high contrast over a wide temperature range. An implementation of the illumination assembly can include an array of monochromatic light sources positioned on an illumination plane, first and second optical elements, and an exit aperture. A chief ray of each light source within the array of monochromatic light sources can substantially converge at an exit aperture. In such implementations light generated by the array of monochromatic light sources can be used efficiently.

Abstract: The wide-angle lens includes seven lenses and is provided with a diaphragm between the fourth lens and the fifth lens. The first lens is a negative meniscus lens whose convex surface faces the object side. The second lens is a negative meniscus lens whose at least one surface is an aspherical surface and whose concave surface faces an image side. The third lens is a negative meniscus lens whose at least one surface is an aspherical surface and whose concave surface faces the object side. The fourth lens and the fifth lens are positive lenses. The sixth lens is a negative lens whose concave surface faces the image side. The seventh lens is a double convex lens whose convex surfaces face both of the object side and the image side, and configures a joined lens with the sixth lens.

Abstract: An optical image capturing system includes, along the optical axis in order from an object side to an image side, a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, and a seventh lens. At least one lens among the first to the sixth lenses has positive refractive force. The seventh lens can have negative refractive force, wherein both surfaces thereof are aspheric, and at least one surface thereof has an inflection point. The lenses in the optical image capturing system which have refractive power include the first to the seventh lenses. The optical image capturing system can increase aperture value and improve the imagining quality for use in compact cameras.

Abstract: A photographic lens optical system includes first to fifth lenses sequentially arranged in a direction away from an object. The first lens may have a negative refractive power, the second lens may have a positive or negative refractive power, the third lens may have a positive refractive power, the fifth lens may have a negative refractive power, and the fifth lens may have a positive refractive power. The first and fifth lenses may be spherical lenses. The fifth lens may be a biconvex lens. The second to fourth lenses may be aspherical lenses. An aperture stop may be between the second and third lenses. The photographic lens optical system may satisfy the inequality ?2.3<f1G/f<?1.3, wherein f1G is the focal length of the first lens group including the first and second lenses, and f is the focal length of the photographic lens optical system.

Abstract: An image display apparatus according to the present disclosure includes: an image display panel; a backlight device; a first optical element located between the image display panel and the backlight device and configured to deflect a light incident thereon; a second optical element located between the first optical element and the image display panel and configured to change a deflection angle of emitted light according to a voltage applied thereto; a plurality of first lenses located between the first optical element and the backlight device; a plurality of second lenses located between the second optical element and the image display panel; a position detection section configured to detect a viewing position of a viewer; and a control section configured to control the voltage applied to the second optical element, according to the detected viewing position. The first lenses and the second lenses constitute an afocal optical system.

Abstract: The invention proposes a short-distance front projection system, that is to say with a wide angle, occupying a small volume and offering a possibility of focusing as well a zoom function. It makes it possible to obtain images with a diagonal greater than 2 meters, the whole of the optical system being at least 50 cm from the plane of the image. This projector is constructed on the basis of three optical elements: an ocular, an afocal lens system and a final group forming an objective intended to form the intermediate image in front of the mirror.

Abstract: A variable-magnification projection optical system substantially consists of a negative first lens group that is disposed at the most enlargement-side position and is fixed during magnification change, a positive last lens group that is disposed at the most reduction-side position and is fixed during magnification change, and a plurality of lens groups that are disposed between the first lens group and last lens group and are moved during magnification change. The lens groups that are moved during magnification change substantially consist of three lens groups, wherein the most enlargement-side lens group is a negative lens group. Predetermined conditional expressions relating to a back focus of the entire system on the reduction side at the wide-angle end, a focal length of the entire system at the wide-angle end, a focal length of the last lens group, and a focal length of the first lens group are satisfied.

Abstract: A variable-magnification projection optical system substantially consists of a negative first lens group that is disposed at the most enlargement-side position and is fixed during magnification change, a positive last lens group that is disposed at the most reduction-side position and is fixed during magnification change, and a plurality of lens groups that are disposed between the first lens group and last lens group and are moved during magnification change. The most enlargement-side lens group (the second lens group) of the lens groups that are moved during magnification change has a negative refractive power. Predetermined conditional expressions relating to a back focus of the entire system on the reduction side at the wide-angle end, a focal length of the entire system at the wide-angle end, a focal length of the second lens group and a focal length of the last lens group are satisfied.

Abstract: A projection lens of an imaging module and the imaging module are provided. The imaging module further has a light modulator to project a first image with a first aspect ratio. The projection lens comprises an anamorphic lens set and a projection lens set. The anamorphic lens set comprises a first cylinder lens, a second cylinder lens, a bi-convex cylinder lens and a bi-concave cylinder lens, which are set after the light modulator in sequence. The first cylinder lens has at least one flat surface, and the second cylinder lens has at least one convex surface. The anamorphic lens set projects the first image with the first aspect ratio into a second image with a second aspect ratio; the second aspect ratio is different from the first aspect ratio. The projection lens set receives and projects the second image with the second aspect ratio.

Abstract: A projector lens system is provided. The projector lens system comprising, in order from a screen side thereof: a first negative lens that is made of resin and is convex on the screen side; a first positive lens that is made of glass and is biconvex; a stop; a cemented lens that has negative refractive power and is composed, in order from the screen side, of a second negative lens that is made of glass and a second positive lens that is made of glass; and a third positive lens that is made of resin, wherein a refractive index n1 of the first negative lens, a refractive index n2 of the first positive lens, a refractive index n32 of the second positive lens, and a refractive index n4 of the third positive lens satisfy the following conditions: 1.45?n1?1.60; 1.45?n4?1.60; 0.16?n2?n1?0.31; 0.16?n32?n4?0.31; 0.95?n1/n4?1.05; and 0.95?n2/n32?1.05.

Abstract: To provide a projection lens that is compact, lightweight, low-cost, and readily portable, a first lens having a positive power and at least one surface that is an aspheric surface; a second lens having a negative power and having a concave surface on the magnification side; a third lens having a positive power and having a convex surface on the reduction side; and a fourth lens having a positive power are arranged in order from the magnification side. In addition to arranging the lenses telecentrically on the reduction side, the following formulas are satisfied simultaneously, and images formed on the conjugation surface on the reduction side are enlarged and projected on the conjugation surface on the magnification side: formula (A) 0.8<Bf/f; formula (B) 1.1<f1/f<1.6; formula (C) Nd1<1.7, formula (D) vd1<35.

Abstract: A projection lens for projecting image information displayed on a reduction side conjugate position to a magnification side conjugate position, including a negative first lens group, a positive second lens group, a positive third lens group, and a positive fourth lens group arranged in this order from the magnification side, which satisfies predetermined conditional expressions.

Abstract: Wide-angle projection lens, as well as optical engines and projection display devices comprising such projections lens are described. In one embodiment, a wide-angle projection lens is described comprising in sequential order from a screen side a first lens group of negative refractive power, a second lens group of positive refractive power, a third lens group of positive refractive power; and a fourth lens group of positive refractive power. At least one lens group has an aspheric surface. The ratio of the focal length of the wide-angle projection lens (F) to the focal length of each of the lens groups (F1, F2, F3, and F4) is such that |F1/F|>1.3, F2/F>2, 1<F3/F<2 and 1.5<F4/F<8.

Abstract: A projection lens consists of first and second les groups and a stop. The first lens group is formed of a negative lens. The second lens group is formed of three positive lenses and a negative lens. The stop is disposed between the first and second lens groups or in the second lens group. The first and second lens groups are arranged in order from a magnification side. The projection lens is telecentric on a reduction side. The projection lens is configured to satisfy the following conditional expressions (1) and (2): 1.0?f2h/f?5.0??(1) ?2.5?f1/f??0.8??(2) where f2h is a focal length of an aspheric lens of at least one of the first and second positive lenses of the second lens group, f is a focal length of the whole system, and f1 is a focal length of the first lens group.

Abstract: An imaging lens arrangement and method have been described for use with an imaging projector system including a display. A plurality of no more than four lenses can be arranged to receive an object image that emits from the display to propagate through the plurality of lenses to produce a high-resolution projected image from the object image. The imaging projector system has compact configuration, low height profile and provides high performance.

Abstract: A projection optical system receives light from a display device surface and enlarges and projects a display image thereon onto a screen surface. The projection optical system includes one or more reflective surfaces having an optical power between the display device surface and the screen surface, moves at least one optical device having an optical power to adjust focus and satisfies the following conditional formula: ?0.02<{(?1??2)?2}/{(?1+?2)?1}<0.

Abstract: There is provided a lens system (10) that projects projected light onto a screen (6) and includes, in order from the screen (6) side thereof, a first lens (L11) that is a meniscus-type lens with negative refractive power and is convex on the screen (6) side; a second lens (L12), a third lens (L13) and a fourth lens (L14) that are meniscus-type lenses with positive refractive power and are concave on the screen (6) side. In addition, the effective diameter of a concave surface (S6) of the third lens (L13) is larger than the effective diameter of the concave surface (S3) of the second lens (L12), the effective diameter of the concave surface (S8) of the fourth lens (L14) is larger than the effective diameter of the concave surface (S6) of the third lens (L13), and part of the convex surface (S7) of the third lens (L13) and part of the concave surface (S8) of the fourth lens (L14) are located in a shared space along the optical axis.

Abstract: Disclosed herein is an image display device including a light source and a scanner. The scanner includes (a) a first mirror on which a light beam emitted from the light source is incident, (b) a first light deflector on which the light beam output from the first mirror is incident and that outputs collimated light forming a first output angle depending on a first incident angle of the light beam in association with the pivoting of the first mirror, (c) a second mirror on which the collimated light output from the first light deflector is incident, and (d) a second light deflector on which the collimated light output from the second mirror is incident and that outputs collimated light forming a second output angle depending on a second incident angle of the collimated light in association with the pivoting of the second mirror.

Abstract: A projection lens includes a first lens group, a second lens group, and a third lens group. The first lens group is composed of a first lens. The first lens has a concave surface and a convex surface, and the concave surface of the first lens faces a reducing side of the projection lens. The second lens group has positive refractive power, and includes a second lens having positive refractive power and a third lens having negative refractive power. The second lens is a biconvex lens, and the third lens has a concave lens facing the reducing side. The third lens group is composed of a fourth lens, and the fourth lens has a convex surface facing a magnifying side of the projection lens. The first lens group, the second lens group, and the third lens group include at least two aspheric lenses.

Abstract: A zoom lens having less distortion and exhibiting good imaging performance is provided. A zoom lens includes a first lens unit provided at the extremity of an enlargement conjugate side and having a negative refractive power, and a final lens unit provided at the extremity of a reduction conjugate side and having a positive refractive power. The final lens unit includes a cemented lens at the extremity of the reduction conjugate side. The cemented lens has a positive refractive power. The zoom lens satisfies specific conditional expressions.

Abstract: A projection display system comprising a projection display unit including a light source, an image display element, a lighting optical system irradiating a beam of light on the image display element, and a projection optical system projecting an image light from the image display element toward a screen. The projection optical system including a lens group composed of a plurality of lens elements arranged in order toward the screen from the image display element and symmetrically with respect to an optical axis, and a reflecting mirror shaped to be axial-asymmetrical with respect to the optical axis. The projection display system further comprises a screen 5. The projection display unit projects the image light onto a projection plane of the screen to display an image.

Abstract: A projection lens system includes, from the magnified side to the reduced side thereof, a first lens group having negative refractive power, a second lens group having positive refractive power, a third lens group having positive refractive power, and a field lens. The projection lens system satisfies the following conditions: 2.9<TT/f<3.7, and 1.85<f4/f<2.65, where TT is a total length of the projection lens system; f is an effective focal length of the projection lens system; f4 is an effective focal length of the field lens.

Abstract: A projection lens comprises, from a long conjugate side to a short conjugate side, a first lens unit with positive optical power, a second lens unit with negative optical power, and a third lens unit with negative optical power. The first lens unit is configured for correcting chromatic aberration of the projection lens. The third lens unit comprises a meniscus lens which is convex toward to the short conjugate side of the projection lens.

Abstract: A projection zoom lens projects an optical image of rays, which are irradiated from a light source onto a light valve and are modulated by a predetermined image displayed on the light valve, onto a screen. The projection zoom lens includes a plurality of lens groups that is formed as a telecentric system on the reduction side thereof and includes at least two movable lens groups which are movable during zooming. In the projection zoom lens, the plurality of lens groups is arranged to include, in order from a magnification side, at least a first lens group and a second lens group. The first lens group has a negative refractive power, remains stationary during zooming, and performs focusing. The second lens group has a negative refractive power and remains stationary during zooming and focusing.

Abstract: In general, in a first aspect, the invention features a system that includes a microlithography projection optical system. The microlithography projection optical system includes a plurality of elements arranged so that during operation the plurality of elements image radiation at a wavelength ? from an object plane to an image plane. At least one of the elements is a reflective element that has a rotationally-asymmetric surface positioned in a path of the radiation. The rotationally-asymmetric surface deviates from a rotationally-symmetric reference surface by a distance of about ? or more at one or more locations of the rotationally-asymmetric surface.

Abstract: Disclosed is a projection optical system including a projection surface configured such that an image conjugate to an object is projected, plural optical elements having a refractive power, and a deflecting element having no refractive power configured to deflect an optical path of a light beam and to pass the light beam having a deflected optical path between the plural optical elements, wherein a normal line of the projection surface at a center of the projection surface does not pass through the plural optical elements or between the plural optical elements.

Abstract: A projection apparatus includes a light source emitting an illuminating beam, a light valve receiving the illuminating beam to create an image beam, and a projection lens system arranged on a path of the image beam for receiving and projecting the image beam onto a screen. The projection lens system includes four lens elements arranged along the optical axis in order from the screen toward the light valve, namely, first, second, third and fourth lens elements respectively having positive, negative, positive and positive refractive power. The four-piece projection lens system satisfies the condition of 0.79<BFL/TL<0.99; where, BFL is the back focal length of the projection lens system, and TL is the overall length of the projection lens system on the optical axis from a screen side of the first lens element to a light-valve side of the fourth lens element.

Abstract: There is provided a lens system (10) that projects projected light onto a screen (6) and includes, in order from the screen (6) side thereof, a first lens (L11) that is a meniscus-type lens with negative refractive power and is convex on the screen (6) side; a second lens (L12), a third lens (L13) and a fourth lens (L14) that are meniscus-type lenses with positive refractive power and are concave on the screen (6) side. In addition, the effective diameter of a concave surface (S6) of the third lens (L13) is larger than the effective diameter of the concave surface (S3) of the second lens (L12), the effective diameter of the concave surface (S8) of the fourth lens (L14) is larger than the effective diameter of the concave surface (S6) of the third lens (L13), and part of the convex surface (S7) of the third lens (L13) and part of the concave surface (S8) of the fourth lens (L14) are located in a shared space along the optical axis.

Abstract: A projection lens and a projection device using the same are provided. The projection device includes a projection lens and an optical element. The projection lens includes a first lens group and a second lens group from an image side sequentially. The first lens group has a negative refracting power, and the first lens group includes an aspherical lens surface. The second lens group has a positive refracting power. The first lens group has a first focal length f1, and the second lens group has a second focal length f2. The first focal length f1 and the second focal length f2 satisfy the following two conditions: 0.5<|f1/f2|<1.5, and ?35 mm<f1<?15 mm.

Abstract: This invention provides an optical photographing system comprising four lens elements with refractive power, in order from an object side to an image side: a first lens element; a second lens element with positive refractive power, and at least one of the object-side and image-side surfaces thereof being aspheric; a third lens element with negative refractive power having a concave object-side surface and a convex image-side surface, and both of the object-side and image-side surfaces thereof being aspheric; a fourth lens element with positive refractive power, and both of the object-side and image-side surfaces thereof being aspheric; wherein the optical photographing system further comprises an aperture stop positioned between an object and the second lens element. By such arrangement, total track length of the optical photographing system can be effectively reduced. Wide view-angle and high image resolution are also obtained.

Abstract: A projection objective of a microlithographic projection exposure apparatus comprises a manipulator for reducing rotationally asymmetric image errors. The manipulator in turn contains a lens, an optical element and an interspace formed between the lens and the optical element, which can be filled with a liquid. At least one actuator acting exclusively on the lens is furthermore provided, which can generate a rotationally asymmetric deformation of the lens.

Abstract: A projection optical system comprises a plurality of lenses disposed along an optical axis of the projection optical system; wherein the plurality of lenses is dividable into four non-overlapping groups of lenses, such that a total refractive power of each group of lenses is one of a negative refractive power and a positive refractive power; and wherein a refractive power of each lens of the fourth group of lenses is equal to or greater than 0. A lens of the third group of lenses which is disposed directly adjacent to a lens of the fourth group of lenses may have a concave surface facing towards the second object.

Abstract: A projection optical system including a first optical system configured to form a second image conjugate to a first image and a second optical system configured to include a reflective optical element which reflects light from the second image and to project a third image conjugate to the second image onto a projection surface is provided, wherein the first optical system has a Petzval sum with a sign opposite to a sign of a Petzval sum of the second optical system.

Abstract: The invention relates to a method -for improving the imaging properties of a micro lithography projection objective (50), wherein the projection objective has a plurality of lenses (L1, L2, L3, L4, L5, L6, L7, L8) between an object plane and an image plane, a first lens of the plurality of lenses being assigned a first manipulator (ml, Mn) for actively deforming the lens, the first lens being deformed for at least partially correcting an aberration, at least one second lens of the plurality of lenses furthermore being assigned at least one second manipulator, and the second lens being deformed in addition to the first lens. Furthermore, a method is described for selecting at least one lens of a plurality of lenses of a projection objective as actively deformable element, and a projection objective.

Abstract: A wide-angle lens is disclosed that includes a front lens group and a rear lens group that are arranged in order from an object side to an image side with an aperture being arranged between the front lens group and the rear lens group. The front lens group includes at least two lenses arranged toward the object side that have negative powers, and at least one lens arranged toward the image side that has a positive power. The rear lens group includes at least one lens having a positive power. One of the lenses of the front lens group arranged second in order from the object side has a lens face that is arranged into an aspheric surface. The front lens group, the aperture, and the rear lens group make up an image forming system having an angle of view greater than 180 degrees.

Abstract: Very high aperture microlithography projection objectives operating at the wavelengths of 248 nm, 193 nm and also 157 nm, suitable for optical immersion or near-field operation with aperture values that can exceed 1.4 are made feasible with crystalline lenses and crystalline end plates P of NaCl, KCl, KI, RbI, CsI, and MgO, YAG with refractive indices up to and above 2.0. These crystalline lenses and end plates are placed between the system aperture stop AS and the wafer W, preferably as the last lenses on the image side of the objective.

Abstract: In general, in a first aspect, the invention features a system that includes a microlithography projection optical system. The microlithography projection optical system includes a plurality of elements arranged so that during operation the plurality of elements image radiation at a wavelength ? from an object plane to an image plane. At least one of the elements is a reflective element that has a rotationally-asymmetric surface positioned in a path of the radiation. The rotationally-asymmetric surface deviates from a rotationally-symmetric reference surface by a distance of about ? or more at one or more locations of the rotationally-asymmetric surface.

Abstract: The projection zoom lens system includes a negative first lens group, a positive second lens group, a third lens group, a positive fourth lens group, a fifth lens group, and a positive sixth lens group. The lens system is nearly telecentric on a reduction side. During zooming, the second to fifth lens groups are moved while the first and six lens groups remain stationary. The third lens group includes a positive lens LP having a convex surface directed to a magnification side, and a negative lens LN having a concave surface which is directed to the reduction side and has a curvature stronger than a magnification-side surface of the negative lens LN. The conditional expression of 5.0?|fG3/RLN-2| is satisfied. Here, fG3 denotes a focal length of the third lens group, and RLN-2 denotes a radius of curvature of the reduction-side surface of the negative lens LN.

Abstract: An exemplary projection lens system includes, in the order from the magnification side to the reduction side thereof, a first lens with a negative refractive power, a second lens with a positive refractive power, a lens group with a negative refractive power, and a third lens with a positive refractive power. The projection lens system satisfies the formula 0.3<|f1/f(2-4)|<1.0, where f1 is a focal length of the first lens, f(2-4) is an effective focal length of the second lens, the lens group and the third lens.

Abstract: An exemplary projection lens system includes, in order from the magnification side to the reduction side thereof, a first lens with negative refraction power, a second lens with positive refraction power, a third lens with negative refraction power, and a fourth lens with positive refraction power. The projection lens system satisfies the formulae 3.7<TT/f<4; and BFL/f>1.41; where TT is a total length of the projection lens, f is an effective focal length of the projection lens system and BFL is a back focal length of the projection lens system.

Abstract: An exemplary projection lens system includes, in order from the magnification side to the reduction side thereof, a first lens with negative refraction power, a second lens with positive refraction power, a third lens with negative refraction power, and a fourth lens with positive refraction power. The projection lens system satisfies the formulae 3.7<TT/f<4; and BFL/f>1.41; where TT is a total length of the projection lens, f is an effective focal length of the projection lens system and BFL is a back focal length of the projection lens system.

Abstract: A projecting lens system includes a first lens positive in power, a second lens negative in power, a third lens positive in power, and a fourth lens positive in power. The projecting lens system meets a criteria of 1.4<TT/f<1.7; where TT denotes a total length of the projecting lens system and f denotes an effective focal length of the projecting lens system.

Abstract: The present invention provides new projection schemes for wide angle imaging lenses rotationally symmetric about optical axis wherein the field of view of lenses and the size of image sensors are directly reflected without any reference to the effective focal length of the lenses. This invention also provides explicit examples of wide-angle lenses implementing the newly developed projection schemes. According to the present invention, by providing new projection schemes explicitly reflecting the physical quantities of direct interest to the user for industrial applicability, namely, the field of view and the image sensor size, it is possible to realize wide-angle lenses providing the most satisfactory images.

Abstract: An imaging lens includes, in the order from the object side to the image side, a first lens of positive refraction power, a second lens of negative refraction power, a third lens of positive refraction power, and a fourth lens of negative refraction power. The imaging lens satisfies the formulae (1) 1<T/F<1.4; (2) R3/F>4; and (3) S1/S2>3, where T is the overall length of the imaging lens, F is the focal length of the imaging lens, R3 is the radius of curvature of the object-side surface of the second lens, S1 is the vertical distance from the edge to the center of the image-side surface of the third lens, and S2 is the horizontal distance from the edge to the center of the image-side surface of the third lens.