Abstract: A measurement apparatus for measuring a laser focus spot size, which includes a two-dimensional image detector and an imaging system which forms a magnified image of a focus spot located an object plane onto the image detector. The imaging system includes at least an objective lens. A sealed liquid container is secured over a part of the objective lens such as the optical surface of the objective lens is immersed in the liquid (e.g. water) within the container. The liquid container has a window through which the laser beam enters. An image processing method is also disclosed which processes the image obtained by the image detector to obtain the focus spot size while implementing an algorithm that corrects for the effect of ambient vibration.

Abstract: Systems and methods for measuring or inspecting semiconductor structures using broadband infrared radiation are disclosed. The system may include an illumination source comprising a pump source configured to generate pump light and a nonlinear optical (NLO) assembly configured to generate broadband IR radiation in response to the pump light. The system may also include a detector assembly and a set of optics configured to direct the IR radiation onto a sample and direct a portion of the IR radiation reflected and/or scattered from the sample to the detector assembly.

Abstract: Described herein are methods and systems for the optical imaging of a physical specimen of interest that is in contact with, or in close proximity to, the backplane of a high refractive index solid-immersion lens (SIL), wherein the specimen comprises features of interest that act as a local high-refractive index regions. The SIL lens preferably comprises fiducial markers.

Abstract: A microendoscope, and a microendoscopy method related to the microendoscope, each include a tube housing, where an end of the tube housing is shaped and finished to facilitate collection of light emitted from a sample when examined using the microendoscope. In addition, a catadioptric lens assembly, an endomicroscope that includes the catadioptric lens assembly and a microendoscopy method for microscopic analysis that uses the endomicroscope are predicated upon a second element and a third element within the catadioptric lens assembly that each has a dichroic coating. The placement of the dichroic coating on the second element and the third element provides for different magnification factors as a function of illumination wavelength when using the microendoscopy method.

Abstract: The present disclosure relates to an imaging device and an electronic device capable of proposing an imaging device provided with an imaging element having the largest class size for consumer use and a unifocal lens optically brighter and having a simpler lens configuration. An imaging device according to a first aspect of the present disclosure is provided with a unifocal lens including a first lens group having positive power, an aperture stop, and a second lens group having positive power in this order from an object side, and an imaging element curved with a concave surface facing the object side, the imaging element generating an image signal in accordance with incident light collected by the unifocal lens. The present disclosure is applicable to optical devices for astronomical observation applications, for example.

Abstract: An image pickup apparatus includes an image forming optical system having an aperture stop, a first lens, and a second lens, and an imager having a light-receiving surface that is curved to be concave toward the image forming optical system, and a relative partial dispersion for a medium of the first lens differs from a relative partial dispersion for a medium of the second lens, and when a straight line indicated by ?gFLA=?×?dLA+?LA (where ?=?0.00163) has been set, ?gFLA and ?dLA for the medium of the first lens are included in both of an area determined by the following conditional expression (1) and an area determined by the following conditional expression (2), and the following conditional expression (3) is satisfied: 0.68<?LA??(1), ?dLA<50??(2), and 0<|f/Rimg|?1.5??(3).

Abstract: The invention provides an optical imaging lens assembly comprising two lens elements (a positive optical power lens element and a negative optical power lens element) separated by an air gap. The positive lens element of the system may comprise fluorite crystal (CaF2) or other material with similar optical properties. The negative lens element of the system may be made from an optical material, typically glass, having a refractive index ne that lies within the 1.56<ne<1.70 range, and having a main dispersion (nF?nC) within the 0.00860<(nF?nC)<0.01240 range. The lens assembly may include at least one aspherical surface. It has been found that a lens assembly in accordance with the present invention, having aspherical surface(s), achieves significant improvements in the Strehl number (equal to or higher than 80%) for the optical systems with focal ratio of between F/12 and F/5 at every wavelength in the 0.435 ?m to 0.706 ?m range.

Abstract: A variable power optical system for an endoscope comprising a first lens group having a negative power, a second lens group having a positive power and a third lens group, and wherein the first lens group includes at least a negative lens having a concave surface pointing to an image side and a positive meniscus lens having a concave surface pointing to an object side, the second lens group includes at least a meniscus lens having a convex surface pointing to the object side and a cemented lens formed by cementing together a negative lens and a positive lens, and the third lens group includes at least a positive lens having a convex surface pointing to the object side, and wherein the variable power optical system for an endoscope is configured to satisfy a predetermined condition.

Abstract: An imaging lens system includes a lens and a transparent plate. The lens is disposed between an object and a sensor, and the lens includes a flat surface facing the object and an aspheric surface facing the sensor. The transparent plate is connected to the lens and disposed between the object and the lens. An abbe number of the lens is in a range from 30 to 50, an abbe number of the transparent plate is in a range from 40 to 60, and an effective focal length (EFL) of the imaging lens system is in a range from about 0.3 millimeters to about 0.4 millimeters.

Abstract: An imaging mechanism includes: an imaging device; a light receiving section that is provided on one surface of the imaging device; a cover member that covers the one surface of the imaging device and the light receiving section; and a lens unit that has a plurality of lenses including a plano-convex lens having a flat portion and a lens barrel, and that is optically coupled to the light receiving section, the lens barrel fixing the plurality of lenses, wherein the plano-convex lens having the flat portion is provided at a closest position to the imaging device in the plurality of lenses such that the flat portion faces the imaging device, and the flat portion protrudes from an end of the lens barrel toward the imaging device and is fixed to the cover member.

Abstract: A varioscope optical unit has a positive member (9) with a positive refractive power and a negative member (11) with a negative refractive power arranged along an optical axis (OA) so that the negative member follows the positive member along an observation direction (B). At least one of the members is displaceable along the optical axis. Each member has a first termination lens surfaces (23, 27) counter to the observation direction (B) and second termination lens surface (25, 29) in the observation direction. The second termination lens surface of the positive member and the first termination lens surface of the negative member are concave when viewed in the observation direction (B) and have radii of curvature of at most 500 mm. The second termination lens surface of the negative member is convex when viewed in the observation direction (B) and has a radius of curvature of at most 70 mm.

Abstract: An objective for a microscope includes, in order from an object side, a first lens group with positive refractive power, a second lens group with positive refractive power, and a third lens group with negative refractive power. When NA represents a numerical aperture of the objective, FN represents a field number of the objective, ? represents a magnification of the objective, ? represents an Airy disk diameter on an axis to a d-line of the objective, ?max represents a maximum value of an effective diameter of a lens included in the objective, and hexp represents a radius of an exit pupil of the objective, the objective satisfies the following conditional expressions: 0.8?NA?1.5??(1) 1000?FN/|?|/??10000??(2) 1.7??max/2/hexp/NA?4??(3).

Abstract: To off-axis and on-axis aberrations at low cost while having a wide angle of view, an endoscope objective optical system (1) has in order: a negative first lens (L1); a negative second lens (L2) and a third lens (L3) joined to each other; a brightness diaphragm (S); and a positive lens group (G2) having a cemented lens (CL2) including one positive lens and one negative lens joined to each other, and satisfies expressions (1) and (2): 1.0<D3(96 deg)/f_all<10??(1) 1.1<(r1+r2)/(r1?r2)<5.0??(2) where, D3(96 deg) is a distance in which a chief ray of a d-line having an incident angle of 96 degrees that enters the first lens transmits the third lens, f_all is a focal distance of the whole system, r1 and r2 are radii of curvature of an object side surface of the first lens and an image side surface of the second lens, respectively.

Abstract: An imaging optical system includes a positive first lens element having a convex surface on the object side, a negative second lens element having a concave surface on the image side, a third lens element, a positive fourth lens element, a fifth lens element, and a negative sixth lens element provided with at least one aspherical surface that has inflection points other than at an optical axis thereof. The following conditions (1) and (2) are satisfied: 0.86<f/f12<1.20??(1), and ?0.71<(r11?r12)/(r11+r12)<?0.20??(2), wherein f designates the focal length of the imaging optical system, f12 designates the combined focal length of the first and second lens elements, and r11 and r12 designate the radius of curvatures of surfaces on the object side and image side of the first lens element, respectively.

Abstract: A mobile phone lens, including in the direction from an object being imaged to an imaging plane: a first lens group, a diaphragm, a second lens group, a third lens group, and a filter. The first lens group and the third lens group are stationary. The second lens group is adapted to move along an optical axis. The first lens group includes a first lens. The second lens group includes in the direction from the object being imaged to the imaging plane: a second lens, a third lens, and a fourth lens. The third lens group includes in the direction from the object being imaged to the imaging plane: a fifth lens, and a six lens.

Abstract: The present invention provides a compact and high-performance image pickup lens having a fast F-number and capable of suppressing shading by using a curved projection surface. An image pickup lens 10 includes a first lens L1 having a positive refractive power, a second lens L2 having a negative refractive power, a third lens L3 having a positive or negative refractive power, a fourth lens L4 having a positive or negative refractive power, and a fifth lens L5 having a negative refractive power. With regard to the fifth lens L5 among these lenses, at least one surface is aspherical. The above-described image pickup lens 10 satisfies a conditional expression (1): ?2.50<f5/f<?0.10 . . . (1) where f5 is a focal length of the fifth lens L5 and f is a focal length of the entire system of the image pickup lens 10.

Abstract: An optical assembly for a point action camera with a wide field of view includes multiple lens elements configured to provide a field of view in excess of 150 degrees. One or more lens elements has an aspheric surface. The optical assembly exhibits a low inward field curvature of less than 75 microns.

Abstract: An endoscopic objective lens consists of a negative first lens group, a stop, and a positive second lens group, disposed in order from the object side. The first lens group is composed of a cemented lens formed of a first lens and a second lens with a concave surface on the image side cemented in order from the object side. The second lens group is composed of a positive single third lens and a cemented lens formed of a fourth lens and a fifth lens, either of which being a positive lens and the other being a negative lens, and having a positive refractive power, disposed in order from the object side. The endoscopic objective lens satisfies given conditional expressions related to Abbe numbers of the first and second lenses and radii of curvature of the image side and object side surfaces of the second lens.

Abstract: The present disclosure relates an inspection instrument adapted to increase testing throughput in a manufacturing process. In one embodiment, the inspection instrument includes a base plate and a vertical frame, where the base plate and the vertical frame are configured to provide structural support of the inspection instrument, a first mounting mechanism coupled to the base plate, where the first mounting mechanism is configured to hold a sample for inspection, and a second mounting mechanism coupled to the vertical frame, where the second mounting mechanism is configured to hold a set of sensors and an optical system for inspecting the sample. The first mounting mechanism and the second mounting mechanism are decoupled from each other to reduce impact of movements of the sample to the set of sensors and the optical system.

Abstract: Provided is an endoscope objective optical system including, in order from an object side, an aperture stop, a front group having positive refractive power, and a rear group having positive refractive power, in which the rear group is formed by joining a single lens having positive refractive power and a single lens having negative refractive power and is joined to an imaging device; a joining surface between the single lenses has positive refractive power; and the endoscope objective optical system satisfies following Conditional Expression (1): 0.15<fF/fR<0.5,??(1) where fF indicates a focal length of the front group, and fR indicates a focal length of the rear group.

Abstract: A re-imaging optical system is an object side telecentric optical system and includes a front group having a positive refractive power, an aperture stop, and a rear group having a positive refractive power, in this order from the object side, wherein the rear group is composed of a positive lens disposed on the object side and a negative lens disposed on an image side, each of the positive lens and the negative lens is formed of a single lens or a cemented lens, and conditional expressions (1) and (2) are satisfied. Here, fR1 is the focal distance of the negative lens, f is the focal distance of an entire system, and L is a total length from an object surface to an image surface: ?2.2<fR1/f<?0.79??(1) ?0.5<fR1/L<?0.15.

Abstract: An objective lens element having excellent compatibility with optical discs having different base material thicknesses is provided. The objective lens element has optically functional surfaces on an incident side and an exit side. At least either one of the optically functional surfaces on the incident side and the exit side includes a diffraction portion which satisfies at least either one of the following formulas (1) and (2): ?1×?2<0 (“×” represents multiplication)??(1), (sin ?2)/?2=?(sin ?1)/?1??(2), where ?1 is the diffraction angle of a light beam having a diffraction order providing the maximum diffraction efficiency at the wavelength ?1, and ?2 is the diffraction angle of a light beam having a diffraction order providing the maximum diffraction efficiency at the wavelength ?2.

Abstract: A microscope objective lens has an aspheric-surface lens, and a first lens nearest to an object side is a negative lens. It is desirable that at least any one surface of the first lens nearest to the object side is an aspheric surface. Moreover, it is desirable that the microscope objective lens satisfies the following conditional expression (1) ?20<f1/f<?0.1??(1) where, f1 denotes a focal length of the first lens nearest to the object side, and f denotes a focal length of the overall microscope objective lens system.

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: A microscope objective lens OL includes, in order from the object side: a first lens group G1 having a positive refractive power, a second lens group G2, and a third lens group G3 having a negative refractive power, wherein the first lens group G1 includes a positive lens component L1 having a lens surface with a negative refractive power and at least one cemented lens component CL11 having a positive refractive power, the second lens group G2 includes a diffractive optical element GD that joins two diffractive element components L6 and L7 respectively made from different optical materials and which has a diffractive optical surface D on which diffractive grating grooves are formed on the bonded surface of the two diffractive element components, and at least one cemented lens component CL21, and the third lens group G3 includes at least one achromatic lens component CL31.

Abstract: Provided are an ocular zoom optical system which has a wide apparent field of view even on a low power side and in which aberrations are favorably corrected while a sufficient eye relief is secured over the entire zoom range, and an optical instrument including the ocular zoom optical system. The ocular zoom optical system 3 includes, in order from the object side: a first lens group G1 having a negative refractive power; a second lens group G2 having a positive refractive power; and a third lens group G3 having a positive refractive power and at least one aspheric surface. An intermediate image I? is formed between the first lens group G1 and the second lens group G2. During zooming, the third lens group G3 is fixed on the optical axis, and the first lens group G1 and the second lens group G2 are moved in directions opposite to each other with the intermediate image I? interposed therebetween.

Abstract: A lens structure includes an elastomer formed as a lens. The lens has a planar surface and a curved surface opposed to the planar surface. The elastomer of the lens structure may be formed of a base polymer polydimethylsiloxane (PDMS) material. When the lens structure is applied proximate to a camera sensor array of an electronic device, such as a cell phone or a tablet, the combination can function as microscope. By altering parameters of the lens, such as the radius of curvature, it is possible to achieve a wide range of magnification.

Abstract: The diameter of an endoscope insertion portion is reduced, and a wide field angle of an endoscope insertion portion is obtained. An endoscope objective optical system includes, from an object side, a first lens formed of a plano-concave lens having a concave surface facing an image side, a second lens formed of a plano-concave lens having a concave surface facing the object side, an aperture stop, and a third lens formed of a plano-convex lens having a plane surface facing the object side, and satisfies 0.7?|fab/f|0.9 1.7?|fe/fab|?2 2?fb/fa?4 where f: focal length of the entire system; fa: focal length of the first lens; fb: focal length of the second lens; fe: represents focal length of the third lens; fab: combined focal length from the first lens to the second lens.

Abstract: Described is a microscope objective (10, 100, 200) having an objective housing (12) which contains a lens system including a lens unit (60) capable of being moved along the optical axis (O) of the lens system to compensate for the thickness of the coverslip, and further having an adjusting device for adjusting the lens unit (60), said adjusting device including a drive unit (14, 102, 202) and a transmission (42, 44, 46, 48, 50, 52, 54, 56, 62) which is drivable by the drive unit (14, 102, 202) and coupled to the lens unit (60). According to the present invention, the drive unit (14, 102, 202) has a motor (34) and is mounted on the objective housing (12).

Abstract: A high-aperture immersion objective, in particular for confocal applications in fluorescence microscopy and for TIRF applications, having three subsystems of lenses and/or lens groups. The design of the subsystems has made it possible for a relatively large object field of 0.25 mm to be present in the case of a high-resolution numerical aperture of 1.49. Furthermore, improved transparency is possible up to a wavelength of 340 nm.

Abstract: The invention provides a zoom optical system comprising at least three lens groups and designed to implement zooming by varying a separation between the respective lens groups. The zoom optical system includes, on an image plane side with respect to a stop, a lens group comprising a plurality of lenses and having positive refracting power throughout. The lens group having positive refracting power includes therein a first lens and a second lens in order from the object side, an image plane side surface of the first lens being convex toward the object side, and an object side surface of the second lens being concave toward the object side.

Abstract: An objective lens for an endoscope includes, in order from an object side, a front lens group having negative refractive power as a whole, a brightness aperture stop, and a rear lens group having positive refractive power as a whole. The front lens group includes, in order from the object side, a first lens group having negative refractive power and that may include only a single lens; and a second lens group that may include only a single lens, with the second lens group having a lens surface closest to the image side that is of a concave form directed toward the image side, the second lens group having positive refractive power as a whole; and the following condition (1) is satisfied: |f0/f1|?1.1??(1) where f0 is the composite focal length of the front lens group, and f1 is the focal length of the first lens group.

Abstract: A fixed-focus lens module includes an outer lens barrel, an inner lens, a first lens, and a second lens group. The outer lens barrel includes a first open end, a first cavity, and a second open end arranged in the order from the object side to the image side of the outer lens barrel. The inner lens barrel is received in the outer lens barrel adjacent to the first open end. The first lens is received in the inner lens barrel. The second lens group is received in the outer lens barrel adjacent to the second open end. An gap is defined between an outer wall of the inner lens barrel and an inner wall of the outer lens barrel at the first open end, and the center axis of the inner lens barrel is adjustable relative to the outer lens barrel for adjusting the alignment between the first lens and the second lens group.

Abstract: A microscope for virtual-slide creating system has a stage for holding the specimen, a transmitted-light illumination optical system for illuminating the specimen with transmitted light, an objective, a tube lens and an image capture unit. The objective is configured as a dry system of infinity-corrected type with an object-side numerical aperture of 0.8 or greater and a focal length for d-line rays in a range from 8 to 20 mm. The tube lens has a focal length in a range from 160 to 280 mm. The image capture surface of the image capture unit has a long side of 12 mm or longer and a pixel size (?m) satisfying the following condition: a (?m)?(0.61×0.59 (?/m))/NA? where a is the pixel size, and NA? is an image-side numerical aperture.

Abstract: A sub-millimeter solid immersion lens (SIL), comprises a body of a high-index material transparent to electromagnetic radiation in a frequency band to be observed, the body having a flat bottom surface which receives an object to be observed, and the body further having a first upper surface whose limits approximate a zone of a spherical segment and a second upper surface defined by an upper bound of the zone of the spherical segment which prevents passage of electromagnetic radiation in the frequency band to be observed. The SIL may be incorporated into an array, according to other aspects.

Abstract: An objective lens includes, in order from an object side, a front group having negative refractive power, an aperture stop, and a rear group having positive refractive power, wherein the front group includes, in order from the object side, a first lens which is a negative meniscus lens with a convex surface turned to the object side and a second lens which is a negative lens with a concave surface turned to the object side; the rear group includes, in order from the object side, a positive third lens and a fourth lens made up of a positive lens and a negative lens cemented together, and the objective lens satisfies conditional expression (1) below: ?0.8<f—F/f—R<?0.3 ??(1), where f_F is a focal length of the front group, and f_R is a focal length of the rear group.

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 optic comprising a first combination element comprised of at least two individual lens elements, aligned with each other along an optical axis and adhered to each other, a second combination element comprised of at least one individual lens element and an aperture disposed between the first and second combination elements, the surfaces of the imaging optic having less than about 3 minutes tilt relative to the optical axis and less than about 0.005 mm de-center relative to the optical axis. A method of making the imaging optic and an endoscope comprising the imaging optic.

Abstract: A telescope optical system TL comprising, in order from an object side: an objective lens 1; an erecting prism 2; and an eyepiece 3; the objective lens 1 comprising, in order from the object side, a first lens group G1 having positive refractive power, a second lens group G2 having negative refractive power, and a third lens group G3 having positive refractive power, focusing being carried out by moving the second lens group G2 along an optical axis, and an image position being movable by moving the third lens group G3 in a direction perpendicular to the optical axis, thereby providing a telescope optical system having optimum optical performance for a telescope.

Abstract: An objective lens for an endoscope, including a negative front lens group and a positive rear lens group arranged such that an aperture stop is positioned therebetween, wherein the front lens group has at least a front-side negative lens and a front-side positive lens arranged in this order from an object side, and the rear lens group has at least a rear-side positive lens and a cemented lens arranged in this order from the object side, the cemented lens being configured by cementing together negative and positive lenses. The objective lens satisfies following conditions: ?4.5?fF/f??2.0 and 1.5?fRP/f?2.5, where fF (unit: mm) represent of the front lens group, f (unit: mm) represents a total focal length of the front lens group and the rear lens group, and fRP (unit: mm) represents a focal length of the rear-side positive lens.

Abstract: A MEMS-based display device is described, wherein an array of interferometric modulators are configured to reflect light through a transparent substrate. The transparent substrate is sealed to a backplate and the backplate may contain electronic circuitry fabricated on the backplane. The electronic circuitry is placed in electrical communication with the array of interferometric modulators and is configured to control the state of the array of interferometric modulators.

Abstract: A fixed-focus lens disposed between a magnified side and a minified side. The fixed-focus lens has an optical axis and includes a reflective system and a refractive system. The reflective system includes a reflection mirror with a negative refractive power. The refractive system is disposed between the reflection mirror and the minified side and includes a first lens group and a second lens group. The first lens group has a positive refractive power. The second lens group is disposed between the first lens group and the minified side, and has a positive refractive power. The fixed-focus lens satisfies F/H>0.23, where F is an effective focal length and H is an image height.

Abstract: A multiple magnification optical system has a single objective focused upon a specimen at a given working distance. A graded-index lens receives light passing through the objective from the specimen. A beam splitter splits the light exiting the gradient-index lens into a first optical axis and a second optical axis. A first lens is aligned in the first optical axis between the beam splitter and a first camera to focus a magnified image at the first camera. A second camera is situated along the second optical axis from the rear principal plane of the objective so as to obtain unity magnification when the working distance of the objective is set at twice its focal length. Multiple magnifications can be obtained with a single objective by moving the optical system axially to set different working distances from a specimen, and by using multiple beam splitters, or combinations thereof.

Abstract: The present invention offers a dry-type microscope objective lens which has a high NA in the range from low magnification to middle magnification and is lightweight and by which a high-resolution image can be obtained without taking a user time and trouble in observation.

Abstract: A MEMS-based display device is described, wherein an array of interferometric modulators are configured to reflect light through a transparent substrate. The transparent substrate is sealed to a backplate and the backplate may contain electronic circuitry fabricated on the backplane. The electronic circuitry is placed in electrical communication with the array of interferometric modulators and is configured to control the state of the array of interferometric modulators.

Abstract: The invention relates to a microscope objective with preferably anti-symmetric lenses or lens groups with an optical magnification of ?100 and a visual field factor of 20. According to the invention the microscope objective consists of 9 lenses with 3 cemented elements, starting from the object side (left), a lens which is almost a hemisphere L1 with positive refractive power, a meniscus lens L2 with positive refractive power, a two-part cemented element G1 with positive refractive power, another two-art cemented element G2 with positive refractive power, a two-part cemented element G3 with negative refractive power, and finally a meniscus lens L9 with negative refractive power. By using cemented elements and lens pairings of the same construction, production costs can be reduced compared with methods of the prior art while image contrast is improved.

Abstract: An immersion type microscope objective lens OL includes, in order from a cover plate C side, a first lens group G1 having positive refractive power, a second lens group G2 having positive refractive power, and a third lens group G3 having negative refractive power. The first lens group G1 includes at least one cemented lens. The second lens group G2 includes at least two achromatic lenses. The third lens group G3 includes, in order from the object side, an achromatic lens CL31 having a strong concave surface facing an image side, and an achromatic lens CL32 having a strong concave surface facing the object side.

Abstract: An immersion microscope objective lens of the present invention has: in order from an object, a first lens group G1 having positive refractive power and having a cemented lens of a plano convex lens having a plane facing the object and a meniscus lens having a concave surface facing the object, and a single meniscus lens having a convex surface facing the object; a second lens group having positive refractive power and having a plurality of cemented lenses; and a third lens group having negative refractive power and having a cemented meniscus lens having a concave surface facing an image, and a cemented meniscus lens having a concave surface facing the object. And the following conditional expressions 0.12<d0/f<0.25, 0.04<?Ct(p)??Ct(n)<0.09 and ?0.03<?hg(p)??hg(n)<0.00 are satisfied.

Abstract: A wide angle hybrid refractive-diffractive endoscope objective is provided. The objective comprises a negative meniscus lens having a first surface and a second surface; a stop adjacent to the negative meniscus lens; a positive lens adjacent to the negative lens and having a first surface and a second surface; and a hybrid refractive-diffractive element adjacent to the positive lens and having a first surface and a second surface, wherein one of the first surface, or the second surface comprises a diffractive surface, wherein the objective has an effective focal length in a range from about 0.8 mm to about 1.6 mm.

Abstract: An image forming lens has a configuration that an image forming lens IL for receiving parallel beams of light emitted from an observation target object and emerging from an infinity-designed objective lens of a microscope and forming an image of the observation target object in a predetermined position, is constructed of, in order from an object side, a first lens group G1 having positive refractive power and a second lens group G2 having negative refractive power, and the first lens group is constructed of a positive lens (e.g., a biconvex lens L1) and a negative lens (e.g., a negative meniscus lens L2).