Abstract: A real-image finder comprises an objective optical system which forms an image of an object to be viewed; a field frame member located on a primary image forming plane on which the image formed by the objective optical system is formed; an ocular optical system through which the object image formed on the primary image forming plane; and an image erecting optical system which erects the object image formed by the objective optical system. The transparent members are provided on the front and rear surfaces of the field frame, and the thickness of the transparent members are determined so that if a foreign matter sticks to the end surfaces of the transparent members that are opposite to and located away from the field frame member, no foreign matter can be viewed through the ocular optical system.

Abstract: A corrector mirror folds the optical path between the objective and relay portions of a three-mirror anastigmat. The corrector mirror is a non-powered mirror having a nominally flat but higher order aspheric surface. By placing the corrector mirror between the objective portion and an intermediate image formed by the objective portion, the field offset of the anastigmat can be significantly increased. A large field offset makes the off-axis anastigmat ideal for use with an on-axis dewar for infrared imaging applications.

Abstract: An optical system compatible with short wavelength (extreme ultraviolet) radiation comprising four reflective elements for projecting a mask image onto a substrate. The four optical elements are characterized in order from object to image as convex, concave, convex and concave mirrors. The optical system is particularly suited for step and scan lithography methods. The invention increases the slit dimensions associated with ringfield scanning optics, improves wafer throughput and allows higher semiconductor device density.

Abstract: An optical element comprises a lens made of a material for shutting off all or most of light in the infrared region, and an optical low-pass filter, wherein the lens and the optical low-pass filter are incorporated with each other.

Abstract: A reimager comprises precisely two positive lenses wherein the chromatic longitudinal aberration lies within the depth of focus and the thermal image position variation likewise lies within the depth of focus over a temperature range of more than .+-.30.degree. (in the embodiment from -40.degree. C. to +70.degree. C.). Aspheric and diffractive surfaces are utilized and, if required, are joined on respective lens surfaces (31, 51, 53, 71, 73).

Abstract: An optical system compatible with short wavelength (extreme ultraviolet) An optical system compatible with short wavelength (extreme ultraviolet) radiation comprising four reflective elements for projecting a mask image onto a substrate. The four optical elements comprise, in order from object to image, convex, concave, convex and concave mirrors. The optical system is particularly suited for step and scan lithography methods. The invention enables the use of larger slit dimensions associated with ring field scanning optics, improves wafer throughput and allows higher semiconductor device density. The inventive optical system is characterized by reduced dynamic distortion because the static distortion is balanced across the slit width.

Abstract: An ultraviolet (UV) catadioptric imaging system, with broad spectrum correction of primary and residual, longitudinal and lateral, chromatic aberrations for wavelengths extending into the deep UV (as short as about 0.16 .mu.m), comprises a focusing lens group with multiple lens elements that provide high levels of correction of both image aberrations and chromatic variation of aberrations over a selected wavelength band, a field lens group formed from lens elements with at least two different refractive materials, such as silica and a fluoride glass, and a catadioptric group including a concave reflective surface providing most of the focusing power of the system and a thick lens providing primary color correction in combination with the focusing lens group. The field lens group is located near the intermediate image provided by the focusing lens group and functions to correct the residual chromatic aberrations. The system is characterized by a high numerical aperture (type. greater than 0.

Abstract: A photo semiconductor element is covered by a cap with an incident window permitting incident light to penetrate through a translucent member. The photo semiconductor element detects a quantity of incident light penetrating through the translucent member of the incident window. The translucent member of the incident window is made of a material capable of suppressing the transmitting light quantity of incident light components having wavelengths less than 700 nm and larger than 900 nm. A photoelectric current output of the photo semiconductor element is controlled by the incident light penetrating through the translucent member of the incident window. The photo semiconductor element operates in multiple ways as a thermosensing sensor and a photosensing sensor.

Abstract: An infrared afocal lens assembly for providing an observed magnified IR ie scene with a field of view and a substantially less temperature dependent performance. The assembly includes a collecting lens, focusing lens subassembly, an intermediate focal plane, an eyepiece lens subassembly, and an aperture stop. A wide field of view lens subassembly may be used about the focusing lens subassembly. All lenses are made of either GaAs or ZnS, and all lenses are either single lens or doublets.

Abstract: A UV image forming optical system includes a collimating lens which collimates light emitted from a UV light source, and an imaging lens which forms an image of the collimated UV light transmitted through the collimating lens. A rear focal point of the collimating lens adjacent to the imaging lens is located closer to the imaging lens than a last lens surface of the collimating lens on the light emission side. A front focal point of the imaging lens adjacent to the collimating lens is located within the imaging lens. A lens system for UV radiation is also provided, which can be used as an imaging lens for the UV image forming optical system.

Abstract: A method of producing a fused silica glass by thermally converting a polymethylsiloxane precursor, the lens transmitting ultraviolet radiation at wavelengths below 300 nm. without undergoing a marked absorption transition, the lens so produced, and a microlithography system employing a lens of such glass.

Abstract: A lens device for focusing a beam of an ultraviolet-ray region, provided with at least one aspherical lens made of synthetic quartz in which an aspherical portion is formed by a coating a fluororesin on a spherical portion of a side polished to a spherical surface; an ultraviolet-ray emitting device provided with a laser beam source emitting a beam in the ultraviolet-ray region and an object lens which has at least one of the above aspherical lenses; and an optical disc recording device provided with a laser beam source emitting a beam in the ultraviolet-ray region, a light intensity modulating means for modulating the intensity of the laser beam emitted from the laser beam source in accordance with a data signal; and the above object lens.

Abstract: A real image finder includes an objective optical system which forms an image of an object to be viewed on a primary image forming surface, a viewing optical system which is adapted to view the object image formed on the primary image forming surface, and an image erection optical system having four reflection surfaces. The optical axis of the objective optical system is aligned parallel with the optical axis of an ocular optical system. Two of the four reflection surfaces of the image erection optical system are located before the primary image forming surface and the remaining two reflection surfaces are located after the primary image forming surface. The first two reflection surfaces are defined by mirrors and the latter two reflection surfaces are defined by a prism.

Abstract: A high-accuracy multi-wavelength optical microscope for providing a satisfactory contrast of image and much information about a sample. The microscope includes a plurality of light sources, a wavelength varietor independently varying the wavelength of the individual light sources, and polarization plane rotators on the optical path for each light source.

Abstract: A multi-element refractive/diffractive lens system, especially useful in an interferometer of the Fizeau type for forming a partially reflective end of the cavity and focusing collimated laser light at a focus in the cavity, uses a plurality of lens elements all of which are plano concave or plano convex singlets and may be either spherical or cylindrical. The lens has a diffractive element which compensates for aberrations due to the refractive elements of the lens system and enables the lens system to be formed from relatively few refractive elements which are all plano-convex or plano-concave singlets thereby providing cost savings arising out of the reduction in the amount of glass material and number of lens elements. Since the lens system is especially suitable for use in a Fizeau type interferometer, it may be of the type called a Fizeau lens.

Abstract: A FLIR staring array detector system for imaging an object scene using catadioptric optics has a cold shield efficiency approaching unity. The system provides a full format image of the object scene. The catadioptric optics include reflective objective optics for providing an intermediate image of the object scene and refractive relay optics for providing the full format image. The system further includes a staring detector for receiving the full format image.

Abstract: Catadioptric optical systems are disclosed that comprise, objectwise to imagewise, a positive first lens, a meniscus second lens having a convex face oriented objectwise, a meniscus third lens having a concave face oriented objectwise, and a concave spherical mirror having a concave face oriented objectwise. Light from an object passes through the first through third lenses and reflects from the concave mirror to form an image between the third lens and the concave mirror. The system satisfies the condition .vertline.f.sub.123 .vertline./f>10, where f.sub.123 is the aggregate focal length of the first through third lenses, and f is an overall focal length of the system. The first and second lenses are preferably made of a specified optical material, collectively have a positive refractive power, and fulfill the condition .vertline.f.sub.12 .vertline./.vertline.f'.sub.12 .vertline.>1, where f.sub.12 is the aggregate focal length of the first and second lenses, and f'.sub.

Abstract: Multi-spectral images are detected using a refractive objective lens system. Magnesium oxide (MgO) and calcium fluoride (CaF.sub.2) lenses are used to image scenes in both the visible and infra-red (IR) spectrums. The inventors have discovered that the combination of magnesium oxide, only recently made available in a pure crystal form, and calcium fluoride can be used to fabricate an objective lens for imaging objects in both the visible and infra-red spectrums. Moreover, the combination of magnesium oxide and calcium fluoride results in a super-achromatic condition across visible and infra-red spectrums. This chromatically-corrected spectral range includes wavelengths between 0.4 and 5.9 microns which covers medium-wave IR (MWIR), short-wave IR (SWIR), and the near-IR/visible windows. Combinations of MgO and CaF.sub.2 lenses are used in different compound objective lens designs including doublet, Petzval, inverted telephoto, and telephoto arrangements.

Abstract: The projection optical system of the present invention decreases particularly the secondary spectrum of chromatic aberration and minimizes restrictions on lens design. The projection optical system of a projection exposure apparatus which irradiates a light beam from a light source on a mask to expose a pattern of the mask onto a photosensitive substrate through the projection optical system has at least one diffraction optical element, at least one quartz lens, and at least one fluorite lens. The diffraction optical element has a positive power, the quartz lens has a negative power, and the fluorite lens has a positive power. An Ar--F laser is preferably used as a light source.

Abstract: A dual-band optical system 10 preferably for use in the thermal infrared waveband provides initial detection of a target in a first waveband (8-12 .mu.m) having a wide field of view and discriminated target recognition in the second waveband (3-5 .mu.m) at higher magnification and narrow field of view without any field-of-view change mechanism. The system 10 comprises a detector array 11 which is responsive in both wavebands and an optical arrangement 16 with a common objective component 15 for both wavabands. One waveband is transmitted through dichroic beamsplitters 17,18 to the array 11 whereas the other waveband is reflected by the beamsplitters 17,18 and transmitted through a field lens 28 before reaching the array 11. Both wavebands are incident upon a spectrally selective aperture stop 20 providing a large aperture for the low magnification field and a small aperture for the high magnification field.

Abstract: An aspheric optical element formed by depositing material onto a spherical surface of an optical element by controlled deposition to form an aspheric surface of desired shape. A reflecting surface, single or multi-layer, can then be formed on the aspheric surface by evaporative or sputtering techniques. Aspheric optical elements are suitable for deep ultra-violet (UV) and x-ray wavelengths. The reflecting surface may, for example, be a thin (.about.100 nm) layer of aluminum, or in some cases the deposited modifying layer may function as the reflecting surface. For certain applications, multi-layer reflective surfaces may be utilized, such as chromium-carbon or tungsten-carbon multi-layer, with the number of layers and thickness being determined by the intended application.

Abstract: A critical illumination condenser system, particularly adapted for use in extreme ultraviolet (EUV) projection lithography based on a ring field imaging system and a laser produced plasma source. The system uses three spherical mirrors and is capable of illuminating the extent of the mask plane by scanning either the primary mirror or the laser plasma source. The angles of radiation incident upon each mirror of the critical illumination condenser vary by less than eight (8) degrees. For example, the imaging system in which the critical illumination condenser is utilized has a 200 .mu.m source and requires a magnification of 26.times.. The three spherical mirror system constitutes a two mirror inverse Cassegrain, or Schwarzschild configuration, with a 25% area obstruction (50% linear obstruction). The third mirror provides the final pupil and image relay. The mirrors include a multilayer reflective coating which is reflective over a narrow bandwidth.

Abstract: This invention is directed to the production of cuprous halide- or a cuprous-cadmium halide-containing glass articles which are essentially completely opaque to ultraviolet radiation and can be essentially completely opaque to radiation within the region of wavelengths of up to 550 nm, but are transparent to visible radiations having a wavelength longer than the radiation within the region of opacity. The method involves exposing the glass articles to a hydrogen gas-containing atmosphere at a temperature between about 375.degree.-500.degree. C. for a period of at least 18 hours to develop an integral reduced layer in at least one surface of the article having a depth effective to prevent the transmission of ultraviolet radiation and radiation having a wavelength up to 550 nm through the article.

Abstract: Recent UV-lithography is required to provide a fine and sharp pattern with a line width of 0.5 .mu.m or less. The present invention provides a silica glass member adapted for use as an optical element for UV-lithography, by giving consideration to the RMS value of wave front aberration and the slant element of refractive index, which have not been considered in the art. Also, there is provided a silica glass member excellent in durability to the ultraviolet irradiation, by introduction of hydrogen molecules at the synthesis of the silica glass, instead of using a secondary treatment for hydrogen introduction.

Abstract: An ultraviolet (UV) catadioptric imaging system, with broad spectrum correction of primary and residual, longitudinal and lateral, chromatic aberrations for wavelengths extending into the deep UV (as short as about 0.16 .mu.m), comprises a focusing lens group with multiple lens elements that provide high levels of correction of both image aberrations and chromatic variation of aberrations over a selected wavelength band, a field lens group formed from lens elements with at least two different refractive materials, such as silica and a fluoride glass, and a catadioptric group including a concave reflective surface providing most of the focusing power of the system and a thick lens providing primary color correction in combination with the focusing lens group. The field lens group is located near the intermediate image provided by the focusing lens group and functions to correct the residual chromatic aberrations. The system is characterized by a high numerical aperture (typ. greater than 0.

Abstract: Recent UV-lithography is required to provide a fine and sharp pattern with a line width of 0.5 .mu.m or less. The present invention provides a silica glass member adapted for use as an optical element for UV-lithography, by giving consideration to the RMS value of wave front aberration and the slant element of refractive index, which have not been considered in the art. Also, there is provided a silica glass member excellent in durability to the ultraviolet irradiation, by introduction of hydrogen molecules at the synthesis of the silica glass, instead of using a secondary treatment for hydrogen introduction.

Abstract: Recent UV-lithography is required to provide a fine and sharp pattern with a line width of 0.5 .mu.m or less. The present invention provides a silica glass member adapted for use as an optical element for UV-lithography, by giving consideration to the RMS value of wave front aberration and the slant element of refractive index, which have not been considered in the art. Also there is provided a silica glass member excellent in durability to the ultraviolet irradiation, by introduction of hydrogen molecules at the synthesis of silica glass, instead of the secondary treatment for hydrogen introduction.

Abstract: The surface of a zinc selenide substrate is ground to curve in the opposite direction from that which occurs due to the bimetallic effect when zinc sulfide is deposited on a flat substrate by the chemical vapor deposition process. The bowing of the interface that occurs upon cooling of the hot laminate when the surface of the substrate is flat before deposition is compensated for by the pre-figured bowing. A distortion free window for the transmission of infra-red radiation is provided by this invention.

Abstract: Design forms are disclosed for lens triplets comprising a liquid lens element, which are well-corrected for chromatic aberration over a broad wavelength band extending from the ultraviolet region through the visible region into the near infrared region of the electromagnetic spectrum.

Abstract: Lens systems (8, 18, 28, 38, 48, 58) with first and second rigid lens elements and a liquid lens element therebetween are provided. The first and second rigid lens elements (10, 11; 20, 21; 30, 31; 40, 41; 50, 51; 60, 61) and the liquid lens elements (16, 26, 36, 46, 56, 66) co-act with each other to cause the lens system to have substantially diffraction limited performance over a continuous ultraviolet wavelength band, wherein the first and second rigid lens elements and the liquid lens element are configured and positioned with respect to each other according to a selection of particular designs and design forms.

Abstract: A night vision device that uses low cost optics in a balanced arrangement that corrects for distortions created by the low cost optics. The night vision device is a monocular assembly that uses a Gen II or a Gen III image intensifier tube. An objective lens assembly, containing a plurality of low cost lenses, is positioned in front of the image intensifier tube so that the objective lens assembly directs low intensity light onto the input surface of the image intensifier tube. A collimator assembly is positioned proximate the output surface of the image intensifier tube, wherein the collimator assembly collimates the visible image produced by the image intensifier tube. The collimator assembly is comprised of lenses that are identical in shape, size and material to the lenses found within the objective lens assembly. However, the lenses in the collimator assembly are arranged in reverse, as a mirror image of the lenses in the objective lens assembly.

Abstract: The invention relates to a reduction projection lens system of high resolution which enables chromatic aberration to be corrected, and can be improved in terms of transmittance by making the total thickness of the vitreous material forming said lens system. This reduction projection lens system includes refractive and diffractive optical elements and uses as the light source a spectral light source having a center wavelength of up to 300 nm and a wavelength spectral bandwidth of .+-.0.5 pm to .+-.200 pm such as an ArF or KrF excimer laser. The refractive optical element includes at least one aspheric surface, and the refractive and diffractive optical elements are made of the same vitreous material, e.g., SiO.sub.2. conditions, 0.02<.vertline.d/D.vertline.<0.17 and 0.01<.vertline.h/H.vertline.<0.

Abstract: An infrared refractive reimaging afocal telescope (10) has an objective lens group (12), an eyepiece lens (14), and a switching lens group (16). The system (10) provides a plurality of magnification modes in a compact arrangement. Diffractive surfaces are provided on at least one of the objective lenses and the eyepiece lens. Also, the system (10) utilizes switching lenses (40, 42, 44, 46) to provide magnification changes. The diffractive surfaces provide chromatic aberration correction. The system provides for excellent image quality in all modes using a minimum number of lens elements.

Abstract: An extreme wide angle, very large aperture, very compact, solar blind, UV imaging lens system. The lens system has a fused silica polyvinyl alcohol glass color filter, a lens made of fused silica, a lens made of nickel sulfate, a layer of coupling fluid and another lens made of fused silica. Alternatively, sapphire can be used after the color filter instead of the fused silica. An alternative lens is composed of two layers of fused silica, a layer of nickel sulfate, another layer of fused silica, coupling fluid followed by polyvinyl alcohol, a color glass filter and coupling fluid followed by fused silica. In a fourth embodiment, the two layers of fused silica are followed by polyvinyl alcohol, a layer of colored glass filter, fused silica, nickel sulfate, coupling fluid, and fused silica.

Abstract: Design forms are disclosed for infrared imaging systems that can operate at hyper-hemispherical fields of view (e.g., up to 270.degree.) and at wide relative apertures (e.g., up to f/0.7) to produce images having low distortion--typically no more than 20% greater than the distortion resulting when the image size is proportional to the field angle.

Abstract: In a Raman microscope, in particular for a Fourier transform (FT) spectrometer with a lens for magnified imaging of a point-shaped region (1) on a surface of a measuring sample (2) and with a laser for irradiating laser radiation onto the point-shaped region (1), the laser radiation is in the infrared (IR), preferentially in the near-infrared (NIR) region and the lens is a Cassegrain mirror-lens (3, 4) with a convex mirror (3) arranged rotationally symmetrically to an optical axis (5) and with a concave mirror (4) which is likewise rotationally symmetric to the optical axis (5) of the lens, whereby the focal point of the concave mirror (4), lying on the optical axis (5), coincides with the point-shaped region (1) on the surface of the measuring sample (2). In this fashion distortion-free NIR Raman spectra can be taken with simple optical elements.

Abstract: Light from a mercury lamp is focused by an objective lens system and is incident on a specimen to be examined. A focusing optical path of light reflected by the specimen is split into an optical path of an ultraviolet ray and an optical path of visible light by a dichroic mirror having wavelength selectivity. The ultraviolet ray is guided to an ultraviolet CCD camera. The ultraviolet CCD camera supplies a monochrome picture signal to a monochrome display through a first picture processor. On the other hand, the visible light is guided to a color CCD camera. The color CCD camera supplies a color picture signal to a color display through a second picture processor. Therefore, an ultraviolet picture of the specimen is displayed on the monochrome display at a high resolving power and a large magnification. At the same time, a color picture of the specimen is displayed on the color display.

Abstract: In an infrared wide-angle single lens which is as constructed as of a positive meniscus lens, the following conditional expressions (1) through (6) are satisfied:(1) -50.0 th<r.sub.1 <-3.5 th(2) -5 th<r.sub.2 <-1.1 th(3) 2<n<4.5(4) 0.1 f<d<0.8 f(5) 0.5 f<bf<1.5 f(6) 0.5 f<th<2fwhere, an aperture stop is disposed between an object plane and a first surface, d is the distance between the aperture stop and the first surface, th is the lens thickness, bf is the backfocus, r.sub.1 is the radius of curvature of the first surface of the lens, r.sub.2 is the radius of curvature of a second surface of the lens, n is the refractive index of a vitric material of the lens at a wavelength of 10 .mu.m, and f is the focal length.

Abstract: A high resolution objective lens system for use in the ultraviolet region around 250 nm comprising in order from the object side: a first lens unit comprising a meniscus lens component having an object side concave surface having high curvature and a positive lens component, and having a positive refractive power as a whole; a second lens unit comprising at least two cemented lens components and having a positive refractive power as a whole; and a third lens unit comprising a cemented lens component and having a negative refractive power as a whole: each of the lens elements arranged in the lens units being made of an optical material which has, a thickness of at least 5 mm, and an internal transmittance of at least 50% for a ray having a wavelength of 300 nm.

Abstract: Chromatic dispersion between first and second wavelengths of light is corrected by a lens/zone plate combination. The zone plate is adapted both to send most of the first wavelength light into its zeroth order and to send most of the second wavelength light into its first order and to change the focal length of the second wavelength light to coincide with the focal length of the first wavelength light. A preferred embodiment includes a zinc/selinide sulfide lens having a zone plate etched onto one of its surfaces. The zone plate has a multi-step phase profile including four phase levels. The lens/zone plate combination is particularly adapted for use with CO.sub.2 and HeNe lasers to bring their focal lengths into coincidence.

Abstract: A method for the manufacture of quasi-monochromatic microscope dry objectives for a wavelength range from 190 to 360 nanometers proceeds from a basic objective with a specified number of lenses. The basic objective is corrected for a specified wavelength with respect to image aberrations. By using lenses with slightly different production thicknesses and by arranging the lenses at different air separations, objectives for other areas of application are created. All of the objectives have the same number of lenses and virtually the same resolution. The data for three objectives derived from a basic objective are provided as an example.

Abstract: A compound lens for use in a low light level system operating in the near-infrared region. The lens system includes a high light-gathering ability requiring both a large aperture and good transmissivity over the wavelengths of interest. A wide field of view (e.g., 50.degree.) without excessive chromatic and geometric aberrations that generally accompanies systems with a large aperture is provided. Space is provided in the lens system for a variable iris and variable density spot subassembly. Desired optical quantities are obtained through the use of zinc selenide as the material for an aspheric lens. The use of this diamond-turnable infrared material as a field lens yields exceptional performance for a fast (e.g., F/1.25) lens with a wide field of view.

Abstract: An optical system (10) includes a three mirror anastigmat telescope (12) and imager optics (14). The imager optics (14) provide narrow and wide field of view staring of the viewed scene. The optical system is positioned in a turret assembly (50) and folded to provide a sensor. The sensor includes an output laser beam generator (90). The telescope (12) is shared by the infrared system and the laser (90) to provide a simplistic and compact turret arrangement (50) which is well suited for aircraft targeting and designation purposes.

Abstract: A 5.times. laser beam expander lens that is well-corrected for chromatic aberration can be used without refocussing over a wavelength range from 0.365 micron to 1.3 micron.

Abstract: An infrared-transmissive lens formed by using glass including germanium and selenium or germanium and sulfur as main components and a human body detecting device including the lens and a pyroelectric infrared sensor are disclosed. With this configuration, glass having excellent transmissivity of infrared rays, no poisonous characteristic and difficulty to be crystallized is obtained and the glass is subjected to thermal pressing work to form a lens. The lens and a pyroelectric infrared sensor are combined to obtain a scanning type human body detecting sensor device. Further, the scanning type human body detecting sensor device can be used to detect a plurality of human bodies simultaneously.

Abstract: A superachromatic focusing objective lens which focuses wavelengths extending between the ultraviolet and the visible wavelength spectrum and is able to achieve superachromatic correction for three wavelengths within the visible spectrum is disclosed. The present objective lens includes an achromatic lens to assist in the correction spherical and coma aberration, a modified gauss for minimizing spherochromatism, a reversed modified gauss for adding symmetry to aid in the correction of coma, distortion and lateral color aberrations, and a stop located between the modified gauss and the reverse modified gauss. A glass plate is provided for forming a splatter shield to protect the lens from debris, and may be used to define one wall of a vacuum chamber. The elements of the objective lens may be made from various glasses to include calcium fluoride, quartz, and barium fluoride.

Abstract: A three-lens objective has the following characteristics: A front lens consists of a first material of relatively low dispersion, a median lens consists of a second material of relatively larger dispersion, and a rear lens consists of a material of relatively low dispersion. The front lens has positive power, the median lens has negative power, and the rear lens has positive power. The spacing between front lens and median lens is substantially smaller than the distance between median lens and rear lens. Each of the lenses has at least one aspherical surface.

Abstract: An apparatus for enhancing signal to noise ratio in the detection of electromagnetic radiation traversing a capillary tube includes a ball lens and a holding element for holding the ball lens and the capillary tube, the holding element having an aperture so that the aperature and the lens together define an optic axis. The holding element is configured to hold the capillary tube such that the center of the capillary tube traverses the optic axis. The lens has a focal length and is held at such a position relative to that focal length by the holding element such that electromagnetic radiation incident on the aperature is focussed to pass radially through the capillary tube. Thus, the effective path length is 100% of the inside diameter of the capillary tube.

Abstract: An infrared microscope is disclosed which provides illumination for reflectance by the sample. This illumination follows a path through the objective toward the sample, and again, after reflection, through the objective toward the detector The reflectance illumination is directed toward the objective and sample by a fully reflective mirror, which injects approximately half of the interferometer beam into the microscope, and permits substantially all of the reflected beam to reach the detector.

Abstract: A real image type view finder comprising at least one cemented lenses. Of the lens components constituting the cemented lens, a lens component is made of resin. The lens component may be made of material of high transmittance to ultraviolet rays.