Abstract: An optical semiconductor device including one of a light responsive semiconductor element, a light emitting semiconductor element, and a light responsive and light emitting semiconductor element, and a package hermetically sealing the semiconductor element. The package includes a window of silicon that selectively transmits light incident on the semiconductor element and emitted from the semiconductor element. The Si window is connected to the package body using a solder that makes a eutectic alloy with silicon. In this structure, since the eutectic alloy is produced at the junction of the Si window and the package body, the junction is not adversely affected by external influences, especially temperature. Further, since the Si window does not transmit light in the visible light region, the inside of the package cannot be seen from the outside through the Si window after fabrication of the device.

Abstract: A method for producing a narrow band anti-reflective film on a substrate, and the film produced by that method. The improved method being the concept of trimming the outer layer in order to correct for its thickness layers as well as those of the inner layer.

Abstract: A polarization beam splitter which includes a first prism, a second prism, and a dielectric multilayer film which is sandwiched between the first and second prisms is disclosed. The dielectric multilayer film comprising: a plurality of high refractive index layers having a refractive index higher than refractive indices of the first and second prisms; a plurality of intermediate refractive index layers having a refractive index lower than the refractive index of the high refractive index layers; and a plurality of low refractive index layers having a refractive index lower than the refractive index of the intermediate refractive index layers, a reference incident angle .theta..sub.0 of light which is incident on the dielectric multilayer film through the first or second prism being within a range of the following expression:.theta..sub.1 <.theta..sub.0 <.theta..sub.2where ##EQU1## where n.sub.H indicates the refractive index of the high refractive index layers, n.sub.

Abstract: A new solar cell cover comprises a substrate that transmits the spectral region to which the solar cell responds and a multilayer infrared-reflecting coating which incorporates means for suppressing low order reflections. The multilayer coating may also contain ultraviolet or blue coatings and be formed on one or both substrate surfaces. The multilayer coating reflects spectral bands which are adjacent to the short- and long-wavelength limits of the spectral response of the cell. The upper limit wavelength of the short-wavelength reflection band and the lower wavelength limit of the long-wavelength reflection band are independent and may be separately specified.

Abstract: An antireflection coating for a substrate including four layers and having optimized photopic reflectance and optimized for deposition by sputtering. The first layer (the layer farthest from the substrate) has a refractive index less than the refractive index of the substrate and a thickness of about one-quarter wavelength. The second layer (the layer adjacent the first layer) has an refractive index greater than about 2.2 and a thickness of about a half wavelength. The third layer has refractive index less than that of the second layer. The fourth layer (the layer adjacent the substrate) has a refractive index less than about 2.0 and greater than that of the third layer. The combined thickness of the third and fourth layers is less than about a quarter wavelength. The first and third layers may include silicon dioxide. The second layer may include titanium dioxide or niobium oxide. The fourth layer may include indium oxide, tin oxide, indium tin oxide, or zinc oxide.

Abstract: A formable multilayer reflective polymeric body which has a substantially uniform broad bandwidth reflectance over substantially the entire range of the visible spectrum to provide a substantially uniform reflective appearance is provided. The body includes at least first and second diverse polymeric materials, the body comprising a sufficient number of alternating layers of the first and second polymeric materials such that at least 40% of visible light incident on the body is reflected. A substantial majority of the individual layers of the body have optical thicknesses in the range where the sum of the optical thicknesses in a repeating unit of the polymeric materials is greater than about 190 nm, and the first and second polymeric materials differ from each other in refractive index by at least about 0.03.

Abstract: An optical system (20) includes an optical filter (10) having a radiation receiving surface. The filter including a rugate reflection filter having a reflection wavelength characteristic that varies along an axis of the radiation receiving surface. The optical filter includes a plurality of serially disposed rugate coatings (10b, 10c) and has a wavelength rejection gradient that exhibits a linear, logarithmic, or power function of wavelength rejection as a function of position on the radiation receiving surface. The filter has a first optical density associated with a first one of the subfilms, a second optical density associated with a second one of the subfilms, and, for overlapping subfilms, a third optical density within a region wherein at least two subfilms overlap one another. The third optical density is a function of the first optical density and the second optical density. The filter is translated along one or more axes thereof for providing a tunable rejection of incident laser threat radiation.

Abstract: An infrared filter that is formed as a laminated structure including a plurality of layers having substantially uniform thicknesses. The various embodiments include first layers that are relatively thick which are interleaved with second layers that are relatively thin as compared to the first layers. The second layers are generally one quarter wavelength optical thickness at a particular tuned wavelength, whereas the first layers are generally a plurality of quarter wavelength optical thicknesses. Methods for manufacturing the filters are described, including grinding and polishing procedures for obtaining the desired uniformity of thicknesses of said layers.

Abstract: A multiple pass band, thin film optical filter includes a first single pass band filter having a first pass band at a first wavelength, with a first quarterwave stack of thin film layers alternating between layers of a first dielectric material having a first refractive index and layers of a second dielectric material having a second refractive index, the optical thickness of each layer in the first stack being substantially one fourth of the first wavelength. A first half wave layer is interposed within the first stack and has an optical thickness which is an integral multiple of one half of the first wavelength, such that the reflectivities of the portions of the first stack on either side of the first half wave layer are substantially identical.

Abstract: An optical multilayer thin film and a beam splitter having an optical multilayer thin film are disclosed. The optical multilayer thin film is formed by laminating six layers in sequence. The laminated six layers comprise: a first layer, a third layer and a fifth layer each having a refractive index between 1.63 and 1.64; a second layer and a sixth layer each having a refractive index between 1.37 and 1.38, a fourth layer having a refractive index between 1.9 and 2.3; in which light is allowed to be incident upon the first layer of the optical multilayer thin film at the angle of incidence equal to or greater than 40.degree.. In the beam splitter, the reflectances of S and P polarized components of reflected light are substantially equal to each other over a wide wavelength range and substantially no phase difference exists between the S and P polarized components.

Abstract: An interference filter, also referred to as a minus filter or a notch filter, of the type that reflects a narrow wavelength band while transmitting the wavelength bands from both sides of the spectrum. The filter can be designed for operation in any region from the ultraviolet to the visible through the infra-red regions of the spectrum. According to the invention, the thin film filter consists of uniform layer pairs of dielectric materials of different indices of refraction, deposited periodically on a light transmitting substrate. The overall optical thickness of each pair is one wavelength thick (at the notch wavelength). The two layers in a given pair have unequal thicknesses, each one close to half-wave at the notch wavelength. The technique of adjusting the layer thicknesses to non-normal angles of incidence is employed.

Abstract: An infrared reflecting interference filter capable of transmitting a desired proportion of visible radiation while reflecting a large portion of incident solar radiation is provided. The filter consists of a transparent substrate coated first with a dielectric layer, next a partially metal reflectance layer, and finally an outer protective dielectric layer. In addition, between each metal-dielectric interface is deposited a nucleation or glue layer that facilitates adhesions and improves chemical and mechanical resistance. The interference filters are durable and can be modified to provide a full range of optical and electrical characteristics. The dielectric layer can comprise of composite films consisting of silicon nitride in combination with zirconium nitride, titanium nitride, and/or hafnium nitride.

Abstract: A six-layer anti-reflection coating (20 and 20A) includes three layers (24, 28, and 34) which may be formed from an electrically-conductive metal oxide having a refractive index between about 1.9 and 2.1 at a wavelength of 520 nanometers. Up to a total optical thickness of about one-wavelength of visible light of the electrically-conductive metal oxide may be included in the coating, while still providing less than 0.25 percent photopic reflection.

Abstract: A visible light transmitting, near-infrared reflecting filter for a substrate, comprises a central group of layers (26) including two metal layers (32 and 36) separated by a spacer-layer (34) and bounded by admittance-matching layers (32 and 38). The spacer-layer has an optical thickness of less than one-half wavelength of visible light and the admittance-matching layers have an optical thickness of less than one-quarter wavelength of visible light. On each side of the central group is a group of layers (24 and 28) for boosting near infrared reflectivity of the filter, and for providing low reflection and high transmission for visible light. Each of these near-infrared-reflection-boosting groups including a high refractive index layer (40 and 42) and at least one low refractive index layer (46 and 48).

Abstract: A coated reflector reflective of radiation having two different wavelengths over a wide range of incidence angles, including grazing incidence angles. The coated reflector can be employed in a waveguide for laser radiation useful for medical or other applications, such as a combined HeNe and CO.sub.2 laser beam. Preferably, the coated reflector includes a metal substrate and a multi-layer stack thereon, the multi-layer stack consists of alternating dielectric layers of high and low refractive index material, each pair of adjacent high and low index layers of the stack has a combined matched optical thickness substantially equal to an incident short (e.g., visible) wavelength multiplied by a factor M/2, and the total matched optical thickness of the stack is substantially equal to (2N-1).lambda..sub.L /8, where M and N are positive integers and .lambda..sub.L is an incident long wavelength (such as the wavelength of a CO.sub.2 laser beam).

Abstract: A protective device designed to protect eyes and sensitive photodetectors from high-intensity light over a broad spectral bandwidth while permitting low-intensity and ambient light to be transmitted thereto. In a first embodiment, the device comprises a stack of nonlinear materials having the same linear index of refraction but alternating between a relatively high nonlinear index of refraction and a relatively low nonlinear index of refraction. The respective optical thicknesses of the nonlinear materials are unordered. In a second embodiment, the device comprises a stack of nonlinear materials having the same linear index of refraction and the same optical thickness of a one-half wavelength but unordered nonlinear indices of refraction. In a third embodiment, the device comprises a stack of nonlinear materials having linear indices of refraction alternating between a relatively high linear index of refraction and a relatively low index of refraction and nonlinear indices of refraction which are unordered.

Abstract: A hologram includes an optically transparent base plate having first and second opposite surfaces. A hologram element is provided on the first surface of the base plate, and has a predetermined holographic pattern. An optically transparent member has first and second opposite surfaces. The first surface of the member faces the hologram element. An arrangement serves to prevent light, which successively passes through the transparent base plate, the hologram element, and the member and is then reflected at a boundary between the second surface of the member and an atmosphere, from travelling back to the hologram element.

Abstract: A multi-layer reflection mirror for soft X-ray to vacuum ultraviolet ray, comprises a substrate, a plurality of first layers, and a plurality of second layers formed on the substrate alternately with the first layers. The first layer primarily consists of at least one of single elements, such as ruthenium or of a boride, carbide, silicide, nitride oxide of a transition metal. The second layer primarily consists of at least one of compounds of carbon, silicon (e.g. carbide, nitride and oxide of silicon), boron (e.g. carbide, nitride and oxide of boron), beryllium (e.g. carbide, nitride and oxide of beryllium) and aluminum (e.g. carbide, nitride and oxide of aluminum).

Abstract: A multi-layer graded reflectivity mirror (GRM) with high effective reflectivity is suitable for use in large aperture laser systems with relatively low gain. The GRMs are manufactured with multiple dielectric layers with a thickness profile that eliminates the interference fringes, while providing a reflectivity which tapers smoothly from a peak to zero. The mirror is formed on a substrate having a first surface and a second surface opposite the first. The substrate consists of a material which has low absorption at a given wavelength .lambda.. A first dielectric layer is formed on the first surface of the substrate which has an index of refraction n.sub.1 and having an optical thickness profile with a maximum optical thickness of .lambda./4 at a center which essentially continuously decreases away from the center to a minimum optical thickness of Z at a perimeter P. A second dielectric layer is formed on the first dielectric layer having an index of refraction n.sub.

Abstract: A rearview mirror suitable for vehicles, especially motor vehicles, is composed of a transparent substrate, preferably of soda silica glass and a rear reflection coating comprising a metal mirror layer, preferably chromium, and a dielectric triple interference layer system placed between the metal mirror layer and the transparent substrate. The triple interference layer system comprises, in contact with the metal layer, a dielectric layer having a high refractive index, e.g., titanium dioxide, a next layer having a low refractive index, e.g., silicon dioxide, and next a dielectric layer having a medium refractive index, e.g., a mixed TiO.sub.2 and SiO.sub.2 layer. With the selection of suitable layer thicknesses, a total reflection of at least 40% and a blue reflection tint, independent of the viewing angle, are attained.

Abstract: A four-layer, wideband anti-reflection coating (30) is formed on a light-receiving surface (22) of an indium antimonide (InSb) photodetector (10) to enable detection of light at visible as well as infrared wavelengths. The layers (30a,30b,30c,30d) each have an optical thickness of approximately one-quarter wavelength at a reference wavelength of 1.6 microns. The refractive indices of the layers (30a,30b,30c,30d) are stepped down from the surface (22), having values of approximately 3.2/2.6/1.9/1.45 respectively. The second layer (30b) is preferably formed of silicon suboxide (SiO.sub.0<X<1) by electron-beam deposition of silicon in an oxygen backfill to obtain a refractive index between the indices of silicon and silicon monoxide. A thin passivation layer (26) of germanium or silicon nitride is formed on the surface (22) under the anti-reflection coating (30) to inhibit a flashing effect at infrared wavelengths after exposing to the ultraviolet (UV) and/or visible light.

Abstract: An antireflection coating which comprises a substrate and a multilayered coating is provided. The substrate is made of silicon (Si) or germanium (Ge). The multilayered coating is formed on the substrate and consists of a plurality of layers. In the multilayered coating, a layer of silicon dioxide (SiO.sub.2) of a predetermined thickness is contiguously formed to the substrate.

Abstract: A cathode-ray tube includes a face plate having a light transmittance of at most 50% and a reflectivity reduction film formed on the external surface of the face plate to reduce reflectivity of an external light. The reflectivity reduction film is a low refraction index layer formed by using a coating liquid obtained by dispersing and mixing magnesium fluoride superfine particles to a base coating of an alcohol solution containing a silicon alkoxide. The low refraction index layer can be laminated by a high refraction index layer formed by using a coating liquid obtained by dispersing and mixing tantalum oxide fine particles to the same base coating as that of the low refraction index layer.

Abstract: The optical filter is comprised of a thin film having a multi-layered structure free of a substrate. The multi-layered structure is composed of alternately superposed high refractivity layers and low refractivity layers with one another. Each layer has a dense composition effective to prevent absorption of water and exhibiting substantially the same internal stress. In production of the thin film, there is utilized a substrate soluble to a certain solvent. An optical material of high refractive index and another optical material of low refractive index are alternately deposited by accelerated energy particles on the substrate surface to form a thin film of multi-layered structure. Lastly, the substrate is dissolved into the solvent to separate the thin film to form the optical filter free of the substrate.

Abstract: A polymeric multilayered film which reflects wavelengths of light in the infrared region of the spectrum while being substantially transparent to wavelengths of light in the visible spectrum without the effects of visibly perceived iridescent color is provided. The polymeric multilayered infrared reflecting film comprises at least two diverse, substantially transparent polymeric materials, with the layers having an optical thickness of between 0.09 .mu.m and 0.45 .mu.m and the polymeric materials having a different index of refraction such that light is reflected in the infrared portion of the spectrum. A color masking film is associated with the polymeric film which reflects light substantially uniformly over the visible portion of the spectrum to eliminate perceived iridescent color.

Abstract: A coating, composed of an optically effective layer system for substrates, whereby the layer system has a high antireflective effect. On a front side of the substrate, facing the observer, in sequence from the front side to the observer, a first layer is arranged on the substrate, functioning as dielectric and comprising metal oxide. Thereupon follows a second layer comprising nitride, preferably TiN.sub.x (x is equal to or greater than 1, preferably x=1.05). A third layer follows functioning as dielectric and comprising metal oxide. Thereupon a fourth layer follows comprising nitride, preferably TiN.sub.x (x is equal to or greater than 1, preferably x=1.05). A fifth layer follows functioning as dielectric comprising metal oxide. On a backside of the substrate a TiN.sub.x -layer (x.gtoreq.1, preferably x=1.05) is arranged.

Abstract: A tunable etalon filter is formed by placing mirrors on either side of a spacer of a material which has a relatively large rate of change of refractive index with temperature, and coupling the filter to a thermoelectric cooler to control the temperature of the spacer and, therefore, the index of refraction of the spacer. More specifically, the spacer can be a silicon wafer, or a wafer of zinc sulfide or zinc selenide. The mirrors can be formed of quarter wavelength layer pairs of dielectric coatings of high and low refractive index material. The thermoelectric cooler, which can be coupled to a heat sink, controls the temperature of the spacer by either heating or cooling the spacer. In operation the filter is coarse tuned by adjusting its angle relative to the angle of a received optical signal. It is then fine tuned to the signal by adjusting the temperature of the spacer.

Abstract: High purity (95-99.5 percent) red, orange and yellow filters are disclosed which comprise a periodic stack of relatively low index of refraction dielectric material (L) such as SiO.sub.2 or MgF.sub.2 and absorbing relatively high index material such as silicon or Fe.sub.2 O.sub.3. Together, the low and high index materials provide a high index ratio (typically 1.7 to 2.5). The filters are fabricated according to designs such as (H/2 L H/2).sup.n, typically using only 5 to 7 layers. Despite the very small layer count, these filters provide overall optical performance which is at least the equivalent of all-dielectric filters of 30 or more layers, with color purity that is unachievable by all-dielectric filters and simple low cost design. In addition, our filters have inherently low stress levels and absorb and reflect unwanted light such as blue light.

Abstract: The operable wavelength band of a wide-band half-mirror is windened by inserting, between (1) a substrate having index of refraction n.sub.sub and (2) layers with indices of refraction (n.sub.H .multidot.n.sub.L).sup.2 of the known four-film type dielectric half mirror having a construction represented by n.sub.sub /(n.sub.H .multidot.n.sub.L).sup.2 /air; alternating layers of: (a) high refractive index dielectric substances n.sub.H1, n.sub.H2 . . . ; and (b) low refractive index dielectric substances n.sub.L1, n.sub.L2 . . . ; each film having a thickness of .lambda..sub.o /2. The alternating layers to be inserted have indices of refraction related as follows:n.sub.sub .ltoreq.n.sub.H1 .ltoreq.n.sub.H2 .ltoreq.. . . .ltoreq.n.sub.HN andn.sub.sub .gtoreq.n.sub.L1 .gtoreq.L.sub.L2 .gtoreq.. . . .gtoreq.n.sub.LNThe alternating layer structures according to one of the following formulas (1) or (2) are inserted between the substrate n.sub.sub and layers (n.sub.H .multidot.n.sub.L).sup.2.(2n.sub.H1 .multidot.2n.

Abstract: Three-layer, low color purity, anti-reflection coatings reduce the reflection of visible light rays and display a low color purity when glazings carrying such coatings are oriented at high angles of incidence with respect to a source of visible light. The reflectances are comparable and the color purity values are lower for such glazings, when compared with conventional glazings coated with 1/4-178 -174 wavelength anti-reflection coatings.

Abstract: The present invention describes an optical interference coating useful for transmitting visible radiation and reflecting infrared radiation. The coating is formed from a series of interleaved stacks. The interleaved stacks require only two materials, one having a low index of refraction (L) and the second having a high index of refraction (H). The interleaved stack is made from a first stack of the form (L/a bH L/a) and a second stack of the form (H/a bL H/a). The interleaved stack includes one or more of the combined first stack and second stack in the form [(L/a bH L/a) (H/a bL H/a)]. A stack of the form (L/a bH L/a) is placed on one side of the interleaved stacks to achieve symmetry. The complete visible transmitting and infrared reflecting coating is made from two interleaved stack centered at different wavelength and a third quarterwave stack of the form (L/2 H L/2) centered at a third wavelength. Each interleaved stack and quarterwave stack includes one or more layers.

Abstract: A light mirror and a lamp including a light mirror are disclosed. The light mirror includes a light pervious substrate having a reflecting surface, a metal coating disposed in the reflecting surface, and a dichroic coating disposed on the metal coating. The dichroic coating is designed to reflect essentially all of the visible light spectrum and to transmit infra-red radiation and any unreflected portion of the visible light spectrum. A method for controlling the heat transmission of a cold light mirror is also disclosed.

Abstract: A filter is provided for blocking a major portion of the light impinging thereon but transmitting three narrow spectral pass bands of light having selected wavelengths. The number of pass bands and the wavelengths included in each pass band are selected in accordance with environmental or military conditions dictating the wavelengths of light that need to be filtered. The transmitted narrow spectral pass bands preferably are spaced approximately equally about the CIE chromaticity diagram. The resulting filter enables exceptional seeing and color differentiation while positively blocking broad ranges of potentially injurious light from passing therethrough.

Abstract: A coating for applying to a front side of a substrate, which side is facing an observer, comprises a four-layer system which is optically effective and has a high anti-reflective effect. A first layer of this system is applied onto the front side of the substrate and is, preferably, a highly-refracting TiO.sub.2 layer, the second layer is applied to the first layer and is a low-refracting Al.sub.2 O.sub.3 layer, a third layer of the system is applied to the second layer and is, preferably, a high-refracting TiO.sub.2, while the fourth layer applied to the third layer is, preferably, a low-refracting SiO.sub.2 layer. The layers can be formed by either a pyrolytic method, a plasma-supported chemical vapor deposition method, a sputtering method or a chemical vapor deposition method. Preferably, they are formed by a DC-reactive sputtering method with a magnetron.

Abstract: A multilayer film including contiguous layers of two or more diverse thermoplastic materials of differing refractive indices whereby the film retains a permanent color change as evidence of tampering or an attempt at tampering when the yield point of at least one of the diverse materials has been at least equalled by the strain associated with such tampering or with such an attempt at tampering, and where before such yield point is at least equalled the wavelength of an unsuppressed reflectance of normally incident light is not within the visible spectrum while after such yielded point is at least equalled the reflectance is retained in the visible spectrum.

Abstract: An automotive lamp comprises a glass bulb having a filament and a light interference film formed on the surface of the glass bulb. The light interference film has a high-refractive index layer and a low-refractive index layer alternately stacked on each other. Each layer has a refractive index ni and a thickness di, wherein i is equal to 1, 2, . . . k. In this case, nidi is equal to (1.+-.0.025)n.sub.2 d.sub.2, wherein i is equal to 3.about.(k-1), n.sub.1 d.sub.1 is equal to (1.+-.0.025)n.sub.2 d.sub.2, and n.sub.k d.sub.k is equal to (1.+-.0.025)n.sub.2 d.sub.2. The maximum value of the reflectance of the film is more than 91% within visible light range, and the 50% transmitting wavelength is from 515 nm to 542 nm.

Abstract: An interference film filter for use in a copying machine as mounted on an optical path of light traveling through an image-forming lens for preventing transmission of the light in a predetermined wavelength range. The filter comprises a transparent glass substrate, and interference films each consisting of a plurality of layers formed by vapor deposition on the substrate. The interference films include a film disposed centrally of the substrate, and an opposed pair or pairs side films. Each of the side films has a greater optical film thickness than the center film or a film disposed immediately inwardly.

Abstract: The present invention provides an optical interference film, made of multiple layers of polymers, which reflects wavelengths of light in the infrared region of the spectrum while being substantially transparent to wavelengths of light in the visible spectrum. The optical interference film includes multiple alternating layers of at least first, second, and third diverse, substantially transparent polymeric materials A, B, and C, with the layers being of an optical thickness of between about 0.09 and 0.45 micrometers. Each of the polymeric materials has a different index of refraction, n.sub.i, and the refractive index of the second polymeric material is intermediate the respective refractive indices of the first and third polymeric materials.

Abstract: A novel optical filter structure for selectively blocking radiation of predetermined wavelength is described which comprises a plurality of alternate first and second layers deposited on a substantially transparent substrate, the first layers comprising a transparent nontransitioning material of first refractive index, the second layers comprising a material characterized by a transition from ferroelectric phase having second refractive index to nonferroelectric phase having third refractive index different from the first and second indices upon being heated to a characteristic transition temperature, each of the first and second layers having a thickness substantially equal to one-fourth times the ratio of the predetermined wavelength to the respective index of refraction.

Abstract: The present invention provides an optical interference film, made of multiple layers of polymers, which reflects wavelengths of light in the infrared region of the spectrum while being substantially transparent to wavelengths of light in the visible spectrum. The optical interference film includes multiple alternating layers of at least first, second, and third diverse, substantially transparent polymeric materials A, B, and C, with the layers being of an optical thickness of between about 0.09 and 0.45 micrometers. Each of the polymeric materials has a different index of refraction, n.sub.i, and the refractive index of the second polymeric material is intermediate the respective refractive indices of the first and third polymeric materials.