Abstract: An imaging optical system includes a plurality of optical systems each including a plurality of optical members, a first reflection member, disposed for each one of the optical systems, configured to reflect light when the light passing through the plurality of optical members, and a variable aperture member having an opening disposed at an image sensor side when viewed from the first reflection member, the variable aperture member configured to change a size of the opening through which the light reflected from the first reflection member passes through, and at least a part of the variable aperture member is disposed at a position overlapping with an area corresponding to a first lens, disposed at the most object side in the plurality of optical members, along an optical axis direction.

Abstract: The invention relates to a tiltable mirror (1) for optical image stabilization in an optical imaging system (100), the tiltable mirror (1) comprising—a rigid mirror substrate (1S) with a planar reflective layer (1R) on a front side of the mirror substrate (1S) for reflecting incident light (500) in an optical imaging system (100), —a mirror frame (1F), wherein the mirror substrate (1S) is arranged tiltably in the mirror frame (1F), —an actuator (2) for tilting the mirror substrate (1S) around a primary (x) and a secondary (y) tilt axis with respect to the mirror frame (1F). The invention further relates to an optical imaging system comprising a tiltable mirror (1) according to the invention.

Abstract: A camera module includes a lens module including at least one lens, a housing configured to accommodate the lens module, a first reflection module disposed in front of the lens module, a second reflection module disposed behind the lens module, an image sensor module configured to receive light reflected from the second reflection module, and a light-blocking structure, disposed in the housing between the second reflection module and the image sensor module, including an aperture configured to pass light and an infrared cutoff filter disposed to cover the aperture.

Abstract: An optical imaging system includes five lenses in which a first lens includes a positive refractive power and a concave object-side surface, and a second lens includes a positive refractive power and a concave image-side surface. The first to fifth lenses are sequentially disposed from an object side to an image side.

Abstract: There is provided a projection lens that is mounted on a housing of a projection device including an electro-optical element. The projection lens includes a first holding frame through which light emitted from the housing passes, a second reflective part that refracts an optical axis of light emitted from the first holding frame and includes a pair of side surfaces facing each other, and a second holding frame that holds the second reflective part and includes a pair of first holes provided at positions corresponding to the pair of side surfaces; and each of the pair of side surfaces has a gap between itself and the second holding frame.

Abstract: An image capturing device and a mobile electronic device are provided. The image capturing device includes a frame, a flexible circuit board connected to the frame, a camera lens assembly mounted at the middle of the frame, a first prism unit mounted at one end of the frame and at an object side of the camera lens assembly to receive light, a second prism unit mounted at another end of the frame and at an image side of the camera lens assembly, a first voice coil motor for driving the second prism unit to rotate about an X-axis direction in the frame, and a second voice coil motor for driving the second prism unit to rotate about a Y-axis direction in the frame. The first and second voice coil motors are electrically connected to the flexible circuit board. An overall appearance of a mobile electronic device is not affected.

Abstract: An optical imaging system includes a first lens having a positive refractive power and a concave object-side surface, a second lens having a positive refractive power, a third lens having a negative refractive power, a fourth lens having a positive refractive power, and a fifth lens having a positive refractive power and a concave image-side surface. The first through fifth lenses are sequentially disposed in ascending numerical order from an object side of the optical imaging system toward an imaging plane of the optical imaging system.

Abstract: A reflection module includes: a holder; and a reflective member mounted on the holder and including an incident surface, a reflective surface, and an emitting surface. The holder includes a cover portion covering a portion of the emitting surface. An area of the cover portion covering the emitting surface increases in a direction toward a lower portion of the emitting surface.

Abstract: The present disclosure provides an imaging optical lens assembly, including, in order from an object side to an image side: a first lens element with negative refractive power having an object-side surface being concave in a paraxial region, a second lens element with positive refractive power, a third lens element with negative refractive power, a fourth lens element with positive refractive power, and a fifth lens element with negative refractive power having an image-side surface being concave in a paraxial region and at least one convex shape in an off-axial region on the image-side surface, wherein the imaging optical lens assembly has a total of five lens elements.

Abstract: In a lens assembly structure comprising a plurality of lens assemblies, according to the present invention, at least one part of assemblies among the plurality of lens assemblies comprises: a first lens group having a positive refractive power or a negative refractive power; a second lens group having a positive refractive power; and a bending structure for bending an optical path of the first lens group such that the optical path corresponds to an optical axis direction of the second lens group, wherein the bending structure is disposed on the optical path of the first lens group and an optical path of the second lens group, optical axes of the first lens groups disposed in each of the at least one part of lens assemblies meet at one point, and optical axes of the second lens groups disposed in each of the at least one part of lens assemblies may form a triangle.

Abstract: A front projection display device is provided including an image-generating source configured to generate an image, a wide angle lens system adapted to receive the image, and a screen. The wide angle lens system may be configured to increase distortion of the image in a first stage and decrease distortion of the image in a second stage. The screen may be configured to receive the image from the wide angle lens system on a first side and reflect the image back to a viewer on the first side. In another embodiment, a screen is provided for a front projection system, the screen may be configured to receive light from a steep angle and may include any number of surface topographies configured to reflect light back to the viewer along a desired viewing plane.

Abstract: Lens assemblies comprising, from an object side to an image side, a positive first lens element L1 with a first optical axis and a first lens width W1, a light folding element, a negative second lens element L2 and a plurality of additional lens elements L3-LN with a common second optical axis, and an image sensor having a sensor diagonal length (SDL), wherein the light folding element is configured to fold light from the first optical axis to the second optical axis, wherein the folded lens has an optical height OH, wherein SDL/OH>0.7 and wherein OH/W1<1.1.

Abstract: An optical imaging system includes, in order from an object side to an image side, a first lens element with positive refractive power, a second lens element, a third lens element, a fourth lens element, and a fifth lens element. Each of the fourth lens element and the fifth lens element includes at least one aspheric surface. The fourth lens element and the fifth lens element are made of plastic. The fifth lens element includes a concave image-side surface and at least one inflection point. An axial distance is formed between each of the first lens element, the second lens element, the third lens element, the fourth lens element, and the fifth lens element, and the optical imaging system further comprises a stop.

Abstract: An optical imaging system includes, in order from an object side to an image side, a first lens element with positive refractive power, a second lens element, a third lens element, a fourth lens element, and a fifth lens element. Each of the fourth lens element and the fifth lens element includes at least one aspheric surface. The fourth lens element and the fifth lens element are made of plastic. The fifth lens element includes a concave image-side surface and at least one inflection point. An axial distance is formed between each of the first lens element, the second lens element, the third lens element, the fourth lens element, and the fifth lens element, and the optical imaging system further comprises a stop.

Abstract: An endoscope objective optical system includes an optical-path deflecting prism group and a lens group. A visual-field direction of the endoscope objective optical system is variable by moving a prism in the optical-path deflecting prism group. The optical-path deflecting prism group includes, in order from an object side, a first prism, a second prism, and a third prism, which are disposed to be in mutual proximity. The visual-field direction is variable to a first direction by the first prism undergoing a rotational movement with respect to the second prism, and the visual-field direction is variable to a second direction which differs from the first direction, by the first prism and the second prism undergoing rotational movement integrally with respect to the third prism.

Abstract: A 3-D image pick-up device is disclosed, the device including: a PCB mounted with two camera modules including an image sensor; and a reinforcing member mounted with two exposure windows, wherein the PCB and the reinforcing member are mutually adhered to allow the camera modules of the PCB to be exposed through the exposure window of the reinforcing member.

Abstract: A display device includes a flat panel display (object image generator) that generates an object image, a retrotransmissive material (imaging element) that has an element surface tilted with respect to an image generation surface of the object image generator, reflects light emitted from the object image located at one side of the element surface twice, and forms the object image as a real image in a plane-symmetrical location with the element surface in a space at the other side of the element surface, and a diffusion angle limiting film (diffusion angle limiting member) that limits a diffusion angle of light from the object image generator toward the imaging element within a predetermined angle range.

Abstract: An optical sight ensures a more accurate aim at feebly discernible targets in the twilight and in dull weather. The sight includes an objective, a reticule, an erecting system consisting of a first and a second positive component, each of which is cemented of two lenses, and an eyepiece. The sight also includes a beam-splitting cube, the beam-splitting face made as a diagonal face, three mirrors and a third positive component cemented of two lenses, a first plane mirror parallel to the beam-splitting face of the cube on the same axis with the third positive component, a second plane mirror perpendicular to the first mirror in front of a focal plane of the eyepiece, and a third mirror tilted to the optical axis and faced with its reflective surface toward the eyepiece arranged between the eyepiece focal plane and the second component of the erecting system.

Abstract: A relay lens system for a high dynamic range projector is provided. The relay lens system comprising: a light input; a light output; one or more lenses configured to relay light from the light input to the light output; and, an aperture stop configured to provide a given numerical aperture to the light being relayed through the one or more lenses, the combination of the given numerical aperture and the one or more lenses are configured to introduce a spherical aberration in the light between the light input and the light output, the spherical aberration changing a shape of a pixel in the light from an approximate square shape at the light input to a function having an upper boundary and a lower boundary based on a distance from a centre of the pixel, and a pixel dimension of a dither pattern in the light entering the light input.

Abstract: A relay lens system for a high dynamic range projector is provided. The relay lens system comprises: a light input; a light output; one or more lenses configured to relay light from the light input to the light output; and, an aperture stop configured to provide a given numerical aperture to the light being relayed through the one or more lenses, the combination of the given numerical aperture and the one or more lenses are configured to: introduce a spherical aberration in the light between the light input and the light output; and, suppress one or more of the following in a ray fan plot of the spherical aberration: local maxima and local minima; and, points where a derivative of the ray fan plot is zero.

Abstract: An imaging optical system includes a bending optical element which bends an object-emanating light bundle, a post-bending lens system on a post-bending optical axis defined by the bending optical element, and an image sensor. An effective optical surface of a large-diameter lens element, having a greatest axial light bundle effective radius, is formed into a non-circular shape by making a length of the effective optical surface from the post-bending optical axis toward a side opposite from the object side smaller than the axial light bundle effective radius, with reference to the axial light bundle effective radius lying on a plane which extends orthogonal to a plane including both the post-bending optical axis and a pre-bending optical axis of the imaging optical system and includes the post-bending optical axis.

Abstract: Some embodiments include an image sensor and a zoom lens assembly including a plurality of movable lens elements arranged to be moved independent of one another. In some embodiments, the plurality of movable lens elements share an optical axis. Some embodiments include a lens and mirror assembly for admitting light to the miniature camera. The lens and mirror assembly includes a folded optics arrangement such that light enters the lens and mirror assembly through a first lens with an optical axis of the first lens orthogonal to the plurality of moveable lens elements. The lens and mirror assembly includes a mirror for folding the path of light from the optical axis of the first lens to the optical axis of the plurality of movable lens elements, and the lens and mirror assembly further includes an actuator for tilting the mirror.

Abstract: An imaging device with a short length and small aberration is provided. A total length D of an image-forming optical system is less than 3.6 mm. A maximum incidence angle of a principle ray on an image forming plane exceeds 33°. Conditions f/fL<?1.50 or f/fL<?0.9, and D/f<1.10 are satisfied where f denotes a focal length of the entire image-forming optical system and fL denotes a focal length of a last lens.

Abstract: Provided is a condensing lens condensing a light from a light source, and a lighting device equipped with the condensing lens. The condensing lens may enable a light to be selectively incident upon a plurality of first incident portions based on an emission angle, may totally-reflect, using a second incident portion, the light refracted by the plurality of first incident portions, and may refract the totally-reflected light using a third incident portion.

Abstract: A unit magnification Wynn-Dyson lens for microlithography has an image field sized to accommodate between four and six die of dimensions 26 mm×36 mm. The lens has a positive lens group that consists of either three or four refractive lens elements, with one of the lens elements being most mirror-wise and having a prism-wise concave aspheric surface. Protective windows respectively reside between object and image planes and the corresponding prism faces. The lens is corrected for at least the i-line LED wavelength spectrum or similar LED-generated wavelengths.

Abstract: An optical system includes an enlarging optical system that enlarges a section of an incident light, a mask that passes some of a light passing through the enlarging optical system, and a reduction optical system that reduces a section of a light passing through the mask.

Abstract: An image capturing optical lens assembly includes, in order from an object side to an image side, a first lens element, a second lens element, a third lens element, a fourth lens element and a fifth lens element. The first lens element with positive refractive power has a convex object-side surface. The second lens element with negative refractive power has a concave object-side surface and a convex image-side surface. The third lens element with refractive power has a concave object-side surface, wherein the surfaces of the third lens element are aspheric. The fourth lens element has positive refractive power, wherein two surfaces of the fourth lens element are aspheric. The fifth lens element has refractive power, wherein two surfaces of the fifth lens element are aspheric, and the fifth lens element has at least one inflection point formed on at least one surface thereof.

Abstract: A wide-angle lens having a field angle larger than 180 degrees includes, in order from an object side to an image side, a front group, a reflection surface, and a back group, wherein the front group includes three lenses having a negative refractive power, the reflection surface is configured to curve an optical axis of the front group at 90 degrees toward the back group, the back group includes four lenses having a positive refractive power, a front principle point is set between a second lens and a third lens from the object side in the front group, and a focal length of an entire system f and a distance between an intersection of the reflection surface and the optical axis of the front group and the front principle point d satisfy the following condition (1) 7.0<d/f<9.0.

Abstract: A imaging assembly for generating a light beam suitable for sintering comprises a lamp housing and a lamp mounted in the lamp housing comprising a filament and a lamp base, wherein the lamp is oriented with the lamp base to the side of the filament. The imaging assembly further comprises a reflector, an aperture, and at least one condenser lens configured to focus light emitted by the filament through the aperture. The imaging assembly further comprises a set of achromatic doublet lenses, each achromatic doublet lens comprising three surfaces optimized to focus light at three wavelengths, wherein the set of achromatic doublet lenses focuses light over a range including the three wavelengths. The imaging assembly further comprises an outer lens, wherein the focused light beam exits the imaging assembly through the outer lens.

Abstract: A projection type display apparatus including an oblique projection optical system having a plurality of lenses is disclosed. A lens nearest to a projection screen has a vertical effective image area through which a light flux passes. The lens is arranged at a position not including an optical axis shared by the largest number of lenses among the plurality of lenses. A flat mirror for returning the optical path is arranged between the particular lens and the projection screen at a predetermined angle to the optical axis. An enlarged image obtained by the light flux returned by the flat mirror is formed toward a display screen.

Abstract: Ring-field, catoptric and catadioptric, unit-magnification, projection optical systems having non-concentric optical surfaces are disclosed. Each system has a system axis with object and image planes on opposite sides of the system axis. The non-concentric surfaces allow for working distances of the object and image planes in excess of 100 millimeters to be achieved, with a ring-field width sufficient to allow a rectangular object-field having a long dimension in excess of 100 mm to be projected.

Abstract: Optical lens attachments and cameras are disclosed. The attachment comprises a coupling mechanism for mating engagement with at least one of a camera and an optical lens. A barrel is coupled at one end to the coupling mechanism. A negative lens unit is coupled to the other end of elongated barrel. A diopter lens is disposed between the barrel and the coupling mechanism. The coupling mechanism, the diopter lens, and the barrel are aligned with an optical axis. Also disclosed is a double swivel optical system, comprising a negative lens unit, a mirror oriented at an angle to the optical axis of the negative lens unit, a roof prism for rotating incident light rays by 90 degrees and inverting an image, a rotation mechanism permitting rotation of the negative lens unit about a vertical axis, an image rotator comprising a prism that can invert an image, the prism disposed within the image rotator, and another rotation mechanism permitting rotation of the roof prism about an optical axis of the image rotator.

Abstract: This invention discloses an image capture lens assembly and an image capture device thereof. The image capture lens assembly, sequentially on an optical axis, includes: a prism, a first lens-group, a second lens-group and a third lens-group. The prism is a full reflective lens. The first lens-group with negative refractive power includes at least one negative lens of the first lens-group, and at least one positive lens of the first lens-group. The second lens-group with positive refractive power comprises at least one positive lens of the second lens-group, and at least one negative lens of the second lens-group. The third lens-group with a positive refractive power comprises at least one lens of the third lens-group with at least one aspheric surface. By such arrangements, the invention can effectively correct aberrations and be applied to compact lens modules.

Abstract: An immersion projection optical system having, for example, a catadioptric and off-axis structure, reduces the portion of an image space filled with liquid (immersion liquid). The projection optical system, which projects a reduced image of a first plane onto a second plane through the liquid, includes a refractive optical element (Lp) arranged nearest to the second plane. The refractive optical element includes a light emitting surface (Lpb) shaped to be substantially symmetric with respect to two axial directions (XY-axes) perpendicular to each other on the second plane. The light emitting surface has a central axis (Lpba) that substantially coincides with a central axis (40a) of a circle (40) corresponding to a circumference of a light entering surface (Lpa) of the refractive optical element. The central axis of the light emitting surface is decentered in one of the two axial directions (Y-axis) from an optical axis (AX).

Abstract: An optical system having a novel imaging method of forming an image of a subject of projection in space the same as if the image were being reflected from a mirror where a mirror does not actually exist is provided, the optical system being provided with a light beam redirecting surface that functions to transmit light while refracting the light and form a real image at a plane-symmetric position, and a mirror surface arranged facing the light beam redirecting surface; in which, by transmitting light emitted from the subject of projection through the light beam redirecting surface, reflecting the transmitted light at the mirror surface, and again transmitting the reflected light through the light beam redirecting surface, an image of a subject of projection arranged at a position on an observation side opposite the mirror surface arranged on the other side across the light beam redirecting surface is formed at a position that is plane-symmetric to the mirror surface with respect to the light beam redirecting

Abstract: Disclosed is an image capturing lens system. The image capturing lens system includes an image capturing lens group having a plurality of lenses and a phase mask located in the image capturing lens group. The phase mask may satisfy phase mask functions that are defined with respect to x and y axes such that a modulation transfer function (MTF) of light is uniformized.

Abstract: Imaging optics having reduced susceptibility to thermally-induced stress birefringence for imaging an object plane to an image plane; comprising an aperture stop positioned between the object plane and the image plane; a first group of optical elements located on the object plane side of the aperture stop; and a second group of optical elements located on the image plane side of the aperture stop. The optical elements in the first and second groups that are immediately adjacent to the aperture stop are refractive lens elements fabricated using optical materials having a negligible susceptibility to thermal stress birefringence, and the other optical elements are a combination of reflective optical elements and refractive lens elements fabricated using optical materials having at most a moderate susceptibility to thermal stress birefringence.

Abstract: An imaging optical system, including an imaging lens group, an image side prism having an entrance surface a reflection surface and an exit surface from which light exits toward an image pickup device, and a first shielding member shielding at least a part of a region on the entrance surface, wherein the region on the entrance surface is located from an edge line of an apex between the entrance surface and the exit surface to a position corresponding to a height h from the edge line, and when L represents a length of the exit surface, ? represents an angle formed between the reflection surface and the exit surface, n represents a refractive index of a surrounding area of the image side prism, and n? represents a refractive index of the image side prism, the height h satisfies a following condition: h=L×cos {?+sin?1(n/n?)}.

Abstract: A projection display system and method is provided. One or more light sources, such as solid state lasers, generates light of various colors that is modulated by a spatial light modulator, such as a digital micro-mirror device. The projection optics of the system include a telecentric rear group of lenses followed by a pair of aspheric lenses formed of a continuous piece of material. A folding mirror, such as a single-piece or multi-piece angular mirror, is disposed along the optical path between the aspheric lenses, to reduce the depth of the enclosure, and an aspheric mirror projects the image onto a projection screen. A folding mirror may be used after the aspheric mirror to further reduce the depth of the enclosure.

Abstract: An optical instrument that includes: an objective lens having an outer convex surface, an inner concave surface, a center, a first optical axis, and a bore cut substantially though the center; a set of objective lenses positioned within the bore and along the first optical axis; a first reflective element disposed along the first optical axis, within a first distance from the convex surface and tilted at a first tilt angle, the first reflective element configured to reflect rays incident along the first optical axis onto a second optical axis; and a second reflective element disposed along the second optical axis and within a second distance from the concave surface, wherein the first tilt angle is selected such that the first and the second distances are minimized.

Abstract: An optical system includes a negative front group having a component of first and second lenses cemented together, an aperture stop, and a positive rear group. The component has: a first face, on the front-direction-object side of the first lens, having a first transmitting surface and an annularly-formed first reflecting surface facing the image side; a second face, at the cemented surface, having a second transmitting surface and an annularly-formed second reflecting surface facing the front-direction-object side; a third face as a transmitting surface on the image side of the second lens; and a fourth face as a transmitting circumferential face of the first lens. The component satisfies the conditions: |nd—RL1?nd—RL2|<0.3 |vd—RL1?vd—RL2|<40 where nd—RL1 and nd—RL2 are refractive indices for d line, of the first and second lenses, respectively, and vd—RL1 and vd—RL2 are Abbe's numbers for d line, of the first and second lenses, respectively.

Abstract: An imaging lens includes negative first lens, negative second lens having a concave surface facing the image side, positive third lens, aperture stop, positive fourth lens, and fifth lens having a concave surface facing the object side, which are arranged sequentially from the object side. At least one of second lens, fourth lens and fifth lens has at least an aspheric surface. The Abbe number of third lens and the Abbe number of fifth lens are less than or equal to 30, and the Abbe number of fourth lens is greater than or equal to 40. Further, the following formula (1) is satisfied: 1.0<(R3?R4)/(R3+R4)??(1), where R3: the paraxial curvature radius of an object-side surface of second lens, and R4: the paraxial curvature radius of an image-side surface of second lens.

Abstract: A catadioptric projection objective has a multiplicity of lenses and at least one concave mirror, and also two deflection mirrors in order to separate a partial beam path running from the object field to the concave mirror from the partial beam path running from the concave mirror to the image field. The deflection mirrors are tilted relative to the optical axis of the projection objective about tilting axes running parallel to a first direction (x-direction). The first deflection mirror is arranged in optical proximity to a first field plane and the second deflection mirror is arranged in optical proximity to a second field plane, which is optically conjugate with respect to the first field plane. A displacement device for the synchronous displacement of the deflection mirrors is provided. The deflection mirrors have different local distributions of their reflection properties in first and second reflection regions, respectively.

Abstract: A zoom lens includes, in order from the object side thereof, a first lens unit having a positive refracting power, a second lens unit having a negative refracting power, a third lens unit having a positive refracting power, a fourth lens unit having a positive refracting power, and a fifth lens unit having a negative refracting power. During zooming from the wide angle end to the telephoto end, the first lens unit and the third lens unit are kept stationary with respect to the image plane, and at least the second lens unit and the fourth lens unit move. The first lens unit includes, in order from the object side, a first sub unit having a negative refracting power, a reflecting optical element that bends an optical path by reflection, and a second sub unit having a positive refracting power. The second sub unit includes a cemented lens.

Abstract: Provided is an imaging lens, the imaging lens including in an orderly way from an object side, a first lens including an incidence surface having a positive (+) refractive power and incident with light, a reflecting surface reflecting the incident light and an exit surface outputting the reflected light; a second lens having a negative (?) refractive power; a third lens having a positive (+) refractive power; a fourth lens having a positive (+) refractive power; a fifth lens having a negative (?) refractive power; a sixth lens having a positive (+) refractive power; and a seventh lens having a positive (+) refractive power, wherein the second lens through the seventh lens are disposed in an orderly way from an exit surface of the first lens.

Abstract: Disclosed are high numerical (NA) catadioptric objectives without a central obscuration, and applications thereof. Such objectives can operate through a wide spectral bandwidth of radiation, including deep ultraviolet (DUV) radiation. Importantly, refractive elements in the catadioptric objectives can be manufactured from a single type of material (such as, for example, CaF2 and/or fused silica). In addition, the elements of such catadioptric objectives are rotationally symmetric about an optical axis. The catadioptric objectives eliminate the central obscuration by (1) using a polarized beamsplitter (which passes radiation of a first polarization and reflects radiation of a second polarization), and/or (2) using one or more folding mirrors to direct off-axis radiation into the pupil of the catadioptric objective. An example catadioptric objective is shown in FIG. 2.

Abstract: A lens optical system includes a first optical system which includes, in order from an object side to an image side along an optical axis, a first lens group having a positive refractive power and including a first reflection member to redirect an optical path of light representing an object from a first direction toward an image sensor, a second lens group having a negative refractive power, a third lens group having a positive refractive power, a fourth lens group having a positive refractive power, and a fifth lens group having a positive refractive power. During zooming from a wide mode to a tele mode, the first lens group and the fifth lens group are fixed, the second lens group moves toward the image side, the third lens group and the fourth lens group move toward the object side, and the fourth lens group performs focusing.

Abstract: A zoom lens includes a plurality of lens groups having at least first, second and third lens groups arranged in order from an object side. The first lens group has a positive refractive power which is firmly secured when the magnification is changed, the second lens group has a negative refractive power which is shifted to the image side when the magnification is changed from the wide angle end to the telescopic end, and the third lens group has a positive refractive power which is firmly secured when the magnification is changed. The first lens group is configured by arranging, in order from the object side, a single lens having a negative refractive power, a prism having a reflection surface to create a 90° bend in a light path, and at least one single lens having a positive refractive power.

Abstract: An apparatus includes a zoom lens and an image pickup element. The zoom lens includes an optical path reflecting lens group including a reflecting member and having a positive refracting power, a movable negative lens group that is disposed in the optical path on the image side of the optical path reflecting lens group, has a negative refracting power, and moves during zooming, a movable positive lens group that is disposed in the optical path on the image side of the movable negative lens group, has a positive refracting power, and moves during zooming, and an aperture stop disposed in the optical path between the movable negative lens group and the movable positive lens group. The optical path reflecting lens group is a lens group located closest to the object side in the zoom lens.

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.