Abstract: An image sensor capable of recording both spectral and polarization properties of light using a single chip device includes an at least 2048 by 2048 array of superpixels. Each superpixel includes an array of spectral pixels, and an adjacent array of polarization pixels. Each spectral pixel includes a spectral filter and a stack of photodiodes, where each photodiode has a different quantum efficiency and is, therefore, sensitive to a different wavelength of light passed by the spectral filter. Each polarization pixel includes a polarization filter and a stack of photodiodes, similar to the spectral pixel photodiode stacks.

Abstract: The present invention provides an optical imaging lens. The optical imaging lens comprises five lens elements positioned in an order from an object side to an image side, each of which has an object-side surface facing the object side and an image-side surface facing the image side. Counting from the object side to the image side, the five lens are labeled as a first lens element, a second lens element, a third lens element, a fourth lens element and a fifth lens element, all of which have refracting power. Through controlling a variable air gap formed between two adjacent lens elements and parameters to meet an inequality, adjustment distance required for focusing the optical imaging lens will be shortened.

Abstract: An athermal compound lens includes a plano-concave lens and a plano-convex lens. The plano-concave lens has a first focal length, a first refractive index n1, and planar object-side surface opposite a concave image-side surface. The plano-convex lens is axially aligned with the plano-concave lens and has (i) a second focal length, (ii) a second refractive index n2, (iii) a planar image-side surface, and (iv) a convex object-side surface between the planar image-side surface and the concave image-side surface. In a free-space wavelength range and temperature range: (a) the first focal length divided by the second focal length is less than ?0.68, and (b) first and second refractive indices n1 and n2 have respective temperature dependences ? ? ? n 1 ? ? ? T ? ? and ? ? ? ? ? n 2 ? ? ? T that satisfy ( ? ? ? n 1 ? ? ? T ) / ( ? ? ? n 2 ? ? ? T ) ? 2.

Abstract: A microscope objective lens includes, in order from an object side, a first lens group having positive refractive power, a second lens group having positive refractive power, and a third lens group having negative refractive power, and is configured such that the first lens group includes, on the most object side, a positive meniscus lens whose concave surface is directed to the object side, such that the second lens group includes a diffractive optical element having positive refractive power, and such that the diffractive optical element is arranged at a position closer to the image than a portion at which the diameter of a light flux passing through the first lens group and the second lens group is the largest.

Abstract: A four-surface narrow field-of-view compound lens includes a first biplanar substrate between a first lens and a second lens, the first lens being plano-convex and the second lens being plano-concave. The compound lens also includes a second biplanar substrate between a third lens and a fourth lens, the third lens being plano-convex and the fourth lens being plano-concave. The second lens and third lens are between the first biplanar substrate and the second biplanar substrate. The first lens, second lens, third lens, and fourth lens are coaxial and are formed of materials having a first, second, third, and fourth Abbe number respectively and focal lengths F1, F2, F3, and F4 respectively. The first Abbe number exceeds the second Abbe number and the third Abbe number exceeds the fourth Abbe number. Ratio F1/F2 may satisfy ?0.32<F1/F2<?0.18 and ratio F4/F3 may satisfy ?0.72<F4/F3<?0.48.

Abstract: An evaluation system that includes a miniature module that comprises a miniature objective lens and a miniature supporting module; wherein the miniature supporting module is arranged, when placed on a sample, to position the miniature objective lens at working distance from the sample; wherein the miniature objective lens is arranged to gather radiation from an area of the sample when positioned at the working distance from the sample; a sensor arranged to detect radiation that is gathered by the miniature objective lens to provide detection signals indicative of the area of the sample.

Abstract: An imaging lens includes in order from an object side a first lens group including a positive refractive power and a second lens group having a negative refractive power, the first lens group and the second lens group including a widest air space therebetween, the first lens group including in order from the object side a negative first lens having a concave face on the object side, a positive second lens having a convex face on both sides, an aperture stop, a negative third lens having a concave face on the object side, a positive fourth lens having a convex face on an image side and a positive fifth lens having a convex face on the image side, and the second lens group including a negative meniscus sixth lens having a concave face on the object side.

Abstract: An objective lens OL comprises: a first lens group G1 disposed on an object side, having positive refractive power as a whole and having a positive lens (plano-convex lens L1) which is disposed closest to the object and of which lens surface closest to the object is a plane or a surface having a low curvature, and at least one cemented lens (cemented lens CL12 or the like); a second lens group G2 disposed on an image side, having negative refractive power as a whole, and having a concave surface facing the image and a concave surface facing the object, which face each other; and a diffractive optical element GD in which two diffractive element constituents made from different optical materials are cemented, which has a diffractive optical surface D formed with diffraction grating grooves on the cemented surface, and which is disposed closer to the object than a position where a principal ray crosses the optical axis.

Abstract: Provided is a lens optical unit, including at least one lens arranged at an object side of a solid-state image sensor. An imaging plane of the image sensor has a non-planar shape causing a sag amount in an optical axis direction to increase as a distance from an optical axis increases, and satisfies the expression: ?×Sag>0, where ? represents a Petzval curvature of an optical unit represented by ?: ? = ? k ? ? 1 r k · ( 1 n k ? - 1 n k ) , rk represents a curvature radius of a kth lens surface from the object side, nk represents a refractive index of a medium before being incident to the kth lens surface from the object side, n?k represents a refractive index of a medium after being emitted from the kth lens surface from the object side, and Sag represents a sag amount in the optical axis direction related to a given point other than the optical axis on the imaging plane.

Abstract: An infrared optical lens system including: a first lens which comprises a crystalline material; and a second lens which comprises an amorphous material and is formed by using molding processing, wherein a refractive index of the first lens is greater than that of the second lens, and the first lens and the second lens are disposed in the order from an object to an image.

Abstract: This invention provides an image capturing lens system comprising three non-cemented lens elements with refractive power: a first lens element with positive refractive power having a convex object-side surface, and both the object-side and image-side surfaces being aspheric; a plastic second lens element with negative refractive power having a concave object-side surface and a convex image-side surface, and both the object-side and image-side surfaces being aspheric; and a plastic third lens element having a convex object-side surface and a concave image-side surface, and both the object-side and image-side surfaces being aspheric. By such arrangement, the space of the image capturing lens system can be allocated much more properly and thereby an image capturing lens system with shorter total track length can be obtained while retaining superior image quality.

Abstract: A micro-lens module including a first lens group and a second lens group is provided. The first lens group disposed between an object side and an image side has a first aspheric surface which is the surface closest to the object side and a second aspheric surface which is the surface closest to the image side. The second lens group disposed between the first lens group and the image side has a third aspheric surface which is the surface closest to the first lens group and a fourth aspheric surface which is the surface closest to the image side. An overall length of the micro-lens module is L, an effective focal length (EFL) of the micro-lens module is f, and an EFL of the second lens group is f2. The micro-lens module satisfies following conditions: 1.5>L/f>0.6, and ?7>f2/f>?14.

Abstract: An optical system comprises, in order from an object side to an image side, a first lens group includes a first lens element with positive refractive power having a convex object-side surface; and a second lens group in order from the object side to the image side includes a second lens element with negative refractive power having a concave image-side surface, a third lens element with positive refractive power having a convex image-side surface, and a fourth lens element with negative refractive power having a concave object-side surface and a concave image-side surface, wherein the image-side surface of the fourth lens element changes from concave at a paraxial region to convex at a peripheral region, and both of the object-side surface and the image-side surface of the fourth lens element are aspheric.

Abstract: A superwide-angle lens system includes a positive front lens group and a negative rear lens group, in that order from the object side, wherein the negative rear lens group serves as a focusing lens group that is moved in the optical axis direction when focusing on an object at infinity to an object at a finite distance. The following condition (1) is satisfied: 1.1<mR<2.0??(1), wherein mR designates the lateral magnification of the negative rear lens group when focusing on an object at infinity.

Abstract: A photographing lens assembly includes, in order from an object side to an image side, a first lens element and a second lens element. The first lens element with positive refractive power has an object-side surface and an image-side surface, wherein the object-side surface and the image-side surface of the first lens element are convex at a paraxial region thereof. The second lens element with refractive power is made of plastic material, and has an object-side surface and an image-side surface, wherein the object-side surface of the second lens element is convex at a paraxial region thereof, the image-side surface of the second lens element is concave at the paraxial region and is convex at a peripheral region thereof, and the object-side surface and the image-side surface of the second lens element are aspheric.

Abstract: There are provided a lens module and a manufacturing method thereof allowing for a reduction in a total length of the lens module. The lens module include: a first lens, a cross section of which, perpendicular to an optical axis, is circular; and a second lens, a cross section of which, perpendicular to an optical axis, is quadrangular.

Abstract: A corrective optical system for an imaging optical system is disclosed, wherein the imaging optical system has an objective having a working space, and whose imaging performance is not corrected for one or more plane parallel plates located in the working space. The corrector optical system resides in the working space between the one or more plane parallel plates and objective and serves to reduce the aberrations introduced by the one or more plane parallel plates. The corrector optical system enables objectives originally designed for film to be used with digital cameras.

Abstract: This invention discloses a thin optical lens assembly, comprising two lens elements with refractive power arranged from an object side to an image side along an optical axis, a bi-convex first lens element with a positive refractive power, a second lens element with a negative refractive power having a concave object-side surface and a convex image-side surface, and an image sensor on an image plane. Each of the two lens elements has two aspheric optical surfaces, and preferably is made of plastic. Additionally, the thin optical lens assembly satisfies the conditions of the present invention in order to reduce the total length and the sensitivity for its use in compact cameras and mobile phones with photographing functions.

Abstract: A micro-lens module including a first lens group and a second lens group is provided. The first lens includes a first lens and a second lens arranged in sequence from the object side to the image side. The second lens is closest to the image side in the first lens group, and a surface of the second lens facing the image side is an aspheric surface. The second lens group includes a third lens and a fourth lens arranged in sequence from the object side to the image side. The first lens group is composed of a first complex lens. The first complex lens includes a plurality of lenses. The lenses are adhered to each other, and a refractive index of at least one lens in the lenses is different from refractive indexes of the other lenses.

Abstract: An optical component, for example a lens, integrally formed of a nano/nano class nanocomposite optical ceramic (NNCOC) material. The constituent nanograin materials of the NNCOC material are selected to tailor the thermal and optical properties of the lens so as to provide a lens with a substantially constant focal length over an operating temperature range and/or an optical system in which the image position does not change appreciably over the operating temperature range.

Abstract: An imaging lens includes in order from an object side a first lens group including a positive refractive power and a second lens group having a negative refractive power, the first lens group and the second lens group including a widest air space therebetween, the first lens group including in order from the object side a negative first lens having a concave face on the object side, a positive second lens having a convex face on both sides, an aperture stop, a negative third lens having a concave face on the object side, a positive fourth lens having a convex face on an image side and a positive fifth lens having a convex face on the image side, and the second lens group including a negative meniscus sixth lens having a concave face on the object side.

Abstract: This invention provides an imaging lens system comprising two non-cemented lens elements with refractive power: a positive first lens element having a convex object-side surface at a paraxial region and a convex or flat image-side surface at the paraxial region; and a negative second lens element having a concave object-side surface at a paraxial region and a concave image-side surface at a paraxial region, and both the object-side and image-side surfaces being aspheric; wherein, the shape of the image-side surface of the second lens element changes from concave when near an optical axis to convex when away from the optical axis. By such arrangement, the imaging lens system has not only a shorter total track length for compact electronic products, but also the advantage of a more comparable focusing performance between the short wavelength and long wavelength applications with improved image quality.

Abstract: A lens system having an infrared filter for a compact camera module is provided. The lens system is an achromatic lens system and has two lenses. The first lens has a positive focal length, and the second lens has a negative focal length. The first lens is made of copper ion containing glass which absorbs infrared light and functions as an infrared filter. The second lens has an Abbe number that is smaller than that of the first lens with a difference between the Abbe numbers of the first lens and the second lens being at least 15.

Abstract: This invention provides a compact imaging lens assembly, in order from an object side to an image side, including a first lens element with positive refractive power having a convex object-side surface and a concave image-side surface with at least one of the two surfaces thereof being aspheric, a second lens element with negative refractive power having a concave object-side surface and a convex image-side surface with at least one of the two surfaces thereof being aspheric, and an aperture stop disposed between the first and second lens elements. There are only two lens elements with refractive power in the compact imaging lens assembly. By such an arrangement, total track length and optical sensitivity of the compact imaging lens assembly can be reduced while a high image quality can also be obtained.

Abstract: An image lens includes a first lens and a second lens. The first lens includes a first and a second surfaces. The second lens includes a third and a fourth surfaces. The image lens satisfies: FB/TTL>0.23; G1R1/F1>1.93; Z/Y>0.27; Z/T<0.89; G2R1/F2<G2R2/F2<G1R2/F2, FB is a distance between the fourth surface and the image plane, TTL is a total length of the image lens, Z is a distance from a central point of the fourth surface to the fourth surface along the optical axis, Y is a distance from the central point of the fourth surface to an edge of the fourth surface along a direction perpendicular to the optical axis, T is a thickness of the second lens, G2R1, G2R2 and G1R2 are curvature radiuses of the third, fourth and second surfaces, F2 is a focal length of the second lens.

Abstract: An image lens includes a first lens and a second lens. The first lens includes a first surface and a second surface. The second lens includes a third surface and a fourth surface. The image lens satisfies: FB/TTL>0.38; R11/F1>2.23; Z/Y>0.11; Z/T<0.42; R23/F2<R12/F2<R24/F2. FB is a distance between the fourth surface and an image plane, TTL is a total length of the image lens, Z is a distance from a central point of the fourth surface to an outer edge of the fourth surface along an optical axis of the image lens, Y is a distance from the central point of the fourth surface to the edge of the fourth surface along a direction perpendicular to the optical axis, T is a thickness of the second lens, R23, R24, R11 and R12 are curvature radiuses of the third, fourth, first and second surfaces, F2 is a focal length of the second lens.

Abstract: An endoscope objective lens includes, in sequence from an object side, a front group which includes a negative first lens having a concave surface faces at image side, a filter, and a positive second lens having a convex surface at the object side and a flat surface or concave surface at the image side; an aperture stop; and a back group which includes a positive third lens having a convex surface at the image side, and a combined lens formed of a plano-convex lens or a biconvex lens and a negative meniscus lens, and satisfies the Conditional Expression (1) and (2): n3>??3/12+5.5,??(1) 2.0>df/Ih>1.5.

Abstract: The present invention provides an image pickup lens including first and second lenses each of which has an Abbe number of greater than 45, which image pickup lens is configured to satisfy the following inequalities (1) and (2): ?0.62<f/f2<?0.55??(1) f/EPD<3.6??(2) where f is the focal length of an entire image pickup lens system, f2 is the focal length of the second lens, and EPD is entrance pupil diameter of the entire image pickup lens system.

Abstract: An imaging device includes a light source; a prism having an imaging surface to be contacted with an object; and an image-forming optical system that forms an image of the object. The image-forming optical system includes a front lens group having a first optical axis tilted relative to the imaging surface; an image plane tilted from a surface perpendicular to the first optical axis of the front lens group; and a rear lens group having a second optical axis shifted in parallel to the first optical axis of the front lens group. The image-forming optical system is arranged to satisfy the following conditional expression: |Aim|/(90°?Ain)<0.5 Where Ain is an acute angle between the imaging surface and the first optical axis, and Aim is an angle between the image plane and a surface perpendicular to the first optical axis.

Abstract: An image pickup lens includes a first lens block with a positive refractive power, a second lens block with a negative refractive power, and an aperture stop. The first lens block includes a first lens substrate, and lens portions 1a and 1b arranged on the first lens substrate. The lens portions 1a and 1b are different from the first lens substrate in at least one of a refractive index and an Abbe number. The second lens block includes a second lens substrate, and lens portions 2a and 2b arranged on the second lens substrate. The lens portions 2a and 2b are different from the second lens substrate in at least one of a refractive index and an Abbe number. The image pickup lens satisfies predetermined conditions relating to a refractive index of the lens portion 2b, and composite thicknesses of the first lens block and the second lens block.

Abstract: A miniaturized optical lens system comprises, in order from the object side to the image side: a first lens element with positive refractive power having a convex object-side surface, a concave image-side surface and one of the surfaces being aspheric; and a second lens element with negative refractive power having a concave object-side surface, a convex image-side surface and one of the surfaces being aspheric. The optical lens system is further provided with an aperture stop. Such arrangements can effectively reduce the volume of the optical lens system, correct aberrations and astigmatism of the system in order to obtain higher image quality.

Abstract: This invention provides a compact imaging lens assembly from an object side toward an image side in order including a first lens element with positive refractive power having a convex object-side surface and a convex image-side surface with at least one of surfaces thereof being aspheric, a second lens element with negative refractive power having a concave object-side surface and a concave image-side surface with at least one of surfaces thereof being aspheric. An aperture stop is positioned between the imaged object and the second lens element. There are two lens elements with refractive power in the compact imaging lens assembly.

Abstract: An image pickup lens, comprises sequentially from an object side: an aperture stop, a first lens being a positive meniscus lens which has a convex surface at the object side and a concave surface at an image side opposite to the object side, and a second lens having a concave surface at the object side and an image side surface whose radius of curvature on an paraxial region is infinite or a negative value, wherein the first lens is the second lens and the image side surface of the second lens includes an aspheric surface to make a positive power strong toward a lens peripheral region, and wherein the image pickup lens is made to satisfy the following conditional formulas. 1.55<n1<1.80??(1) 0.4<D3/f<0.6??(2) 40.0<?2<90.

Abstract: An imaging lens system with two lenses is provided. The imaging lens system with two lenses, along an optical axis from an object side to an image side, comprises an aperture stop; a first lens having positive refractive power and being a biconvex lens; and a second lens having negative refractive power and being a meniscus lens with a concave surface on the object side and a convex surface on the image side.

Abstract: This invention provides a compact imaging lens assembly from an object side toward an image side in order including a first lens element with positive refractive power having a convex object-side surface and a convex image-side surface with at least one of surfaces thereof being aspheric, a second lens element with negative refractive power having a concave object-side surface and a concave image-side surface with at least one of surfaces thereof being aspheric. An aperture stop is positioned between the imaged object and the second lens element. There are two lens elements with refractive power in the compact imaging lens assembly.

Abstract: A lens component of the present invention is made by cementing a lens LA and a lens LB having a refracting power smaller than a refracting power of the lens LA, and satisfies predetermined conditional expressions. Moreover, in an image forming optical system of the present invention which includes a lens group B having a negative refracting power, a lens group C having a positive refracting power and which moves only toward an object side at the time of zooming from a wide angle end to a telephoto end, and one or two more lens groups additionally, one of the lens components of the present invention is used in the lens group B.

Abstract: An imaging lens system with two lenses is provided. The imaging lens system with two lenses, along an optical axis from an object side to an image side, comprises an aperture stop; a first lens having positive refractive power and being a biconvex lens; and a second lens having negative refractive power and being a meniscus lens with a concave surface on the object side and a convex surface on the image side.

Abstract: An imaging lens consisting of in order from an object side to an image surface side, a diaphragm, a first lens that is a meniscus lens having a positive power whose convex surface faces the object side and a second lens that is a lens having a negative power whose concave surface faces the object side, wherein a condition expressed by the following expression is satisfied: 0.05?r1/r2?0.29, where r1 is a center radius curvature of the object side surface of the first lens and r2 is the center radius curvature of the image surface side of the first lens.

Abstract: This invention provides a compact imaging lens assembly in order from an object side toward an image side including a first lens with positive refractive power having at least one of the object-side and image-side surfaces thereof being aspheric, a second lens with negative refractive power having a concave object-side surface and a concave image-side surface with at least one of both surfaces thereof being aspheric, and an aperture stop positioned between the first lens element and the second lens element. There are two lens elements with refractive power in the compact imaging lens assembly.

Abstract: An imaging lens system with two lenses is provided. The imaging lens system with two lenses, along an optical axis from an object side to an image side, includes an aperture stop; a first lens having positive refractive power and being a plano-convex lens with a convex surface on the image side; and a second lens having negative refractive power and being a meniscus lens with a concave surface on the object side and a convex surface on the image side.

Abstract: The present invention provides an image pickup lens, an image pickup apparatus, and a mobile terminal. The image pickup lens includes a lens group. The lens group includes a lens substrate which is a parallel flat plate, and lenses are formed on an object side surface and image side surface of the lens substrate, where a lens with a positive refractive power formed on the lens substrate has an Abbe number of ?p and a lens with a negative refractive power formed on the lens substrate has an Abbe number of ?n. The difference between the Abbe number ?p and the Abbe number of ?n satisfies 10<|?p??n|.

Abstract: A compact short back focus imaging lens system with two lenses is revealed and includes along the optical axis from an object side to an image side: an aperture stop, a first lens with positive refractive power that is a meniscus aspherical lens with convex surface facing the object side, a second lens with negative refractive power that is a meniscus aspherical lens with convex surface facing the image side, an IR cut-off filter and an image sensor. Moreover, the following conditions are satisfied by the imaging lens system: - 0.3 ? f 1 f 2 ? - 0.01 0.25 ? bf TL ? 0.4 wherein f1 is focal length of the first lens, f2 is focal length of the second lens, bf is back focal length of the imaging lens system, and TL (overall length) is the distance from the aperture stop to the image plane.

Abstract: An achromatic lens system is provided with a cemented resin lens having positive refractive power constructed by a resin lens L11 having positive refractive power cemented with a resin lens L12 having negative refractive power, and a close-contact multi-layer type diffractive optical element L11E, the diffractive optical element L11E being disposed to an image side of the cemented resin lens, the diffractive optical element L11E being constructed by cementing two diffractive element members DE11, DE12 each made of different optical materials with each other, and the cemented surface thereof being a diffractive optical surface Gf on which grooves of a diffraction grating are formed, there by being lightweight and easily manufactured, capable of excellently correcting chromatic aberration and spherical aberration at the same time.

Abstract: An imaging lens including, from an object side, a diaphragm, a first lens that is a lens having a positive power whose convex surface faces the object side, and a second lens having a negative power whose concave surface faces the object side, wherein a condition expressed by the following expressions is to be satisfied: ?0.1.?r1/r2<0.1, 0.85?f1/FL?1, and 0.1?d3/FL?0.3 (where, r1: center radius curvature of the object side face of the first lens, r2: center radius curvature of the image surface side face of the first lens, f1: focal distance of the first lens, d3: center thickness of the second lens and FL: focal distance of the entire lens system).

Abstract: The present invention provides an image pickup lens, an image pickup apparatus, and a mobile terminal The image pickup lens includes a lens group. The lens group includes a lens substrate which is a parallel flat plate, and lenses are formed on an object side surface and image side surface of the lens substrate, where a lens with a positive refractive power formed on the lens substrate has an Abbe number of vp and a lens with a negative refractive power formed on the lens substrate has an Abbe number of vn. The difference between the Abbe number vp and the Abbe number of vn satisfies 10<|vp?vn|.

Abstract: It is to provide an imaging lens that can improve optical performance while reducing size and weight. An imaging lens includes, in order from an object side to an image surface side, a diaphragm, a first lens 3 that is a meniscus lens having a positive power whose convex surface faces the object side, and a second lens 4 that is a lens having a negative power whose concave surface faces the object side, wherein conditions expressed by the following expressions are to be satisfied: 0.25<r1/r2?0.45, 0.35?r1/FL?0.42, and 0.85?f1/FL?1 (where, r1: center radius curvature of the object side face of the first lens, r2: center radius curvature of the image surface side face of the first lens, FL: focal distance of the entire lens system, and f1: focal distance of the first lens).

Abstract: In order to provide an image pickup lens, an image pickup module, and a portable information device that make it possible to reduce the risk of deterioration in optical characteristic by achieving satisfactory resolving performance in an area surrounding a shot image, an image pickup lens includes a first lens having an Abbe number of greater than 45 and second lens having an Abbe number of greater than 45 and satisfies mathematical expression (1): ?3.6<f2/f1<?2.5??(1) where f1 is the focal length of the first lens and f2 is the focal length of the second lens.

Abstract: An objective optical system includes, in order from the object side, a first unit having two lenses with negative refracting power and positive refracting power, a stop, and a second unit with positive refracting power to satisfy the following condition: 3.0<fb/fL where fb is the back focus of the objective optical system in air and fL is the focal length of the entire objective optical system.

Abstract: It is to provide an imaging lens that can improve optical performance while reducing size and weight. An imaging lens includes, in order from an object side to an image surface side: a diaphragm 2, a first lens 3 having a positive power whose convex surface faces the object side, and a second lens 4 that is a meniscus lens having a negative power whose convex surface faces the object side, wherein a condition expressed by the following expression is to be satisfied: 0.4?r1/FL?0.55 (where, r1: center radius curvature of the object side face 3a of the first lens, and FL: focal distance of the entire lens system).

Abstract: Optical system for processing a light beam comprises first and second optical means that are convergent and divergent respectively and form an afocal optical device. The first optical means comprises a single convergent lens. According to the invention, this convergent lens provides an order 0 beam and an order 2 beam resulting from the light beam to be processed passing through this lens after having been subjected to a 0 reflection and 2 reflections respectively on the lens faces, and the lens is optimised for the order 2 beam and has an aperture f/# less than 4 for this order 2 beam, with a wave front quality less than ? peak-to-valley, where ? is the wavelength of the light beam to be processed.