Abstract: A method and apparatus are provided for improving the durability of lubricating layers on the surfaces of disks. The lubricating layers on the disks are exposed to ultraviolet and infrared radiation of sufficient duration and energy to reduce the total thickness of the layer but retain at least about 40% of the thickness of the remaining layer in bonded form. The useable lifetime of the lubricating surface is prolonged by treatment of the lubricating layer in this manner.

Abstract: A lamp system is for use in non-destructive testing to illuminate luminescent materials, such as fluorescent dyes. The lamp system has a control unit and a lamp. The lamp has a bulb and a filter. The bulb generates at least a first wavelength of invisible energy and the filter limits other visible wavelength light from the lamp. The lamp has a handle with a trigger. The control unit pulses the lamp on and off when the trigger is depressed. The lumiescent material absorbs the first wavelength of energy and pulses in response when the lamp illuminates the material. The system can be AC or DC operated. It can be operated from an automotive battery. A fault locating system for use with fluorescent dyes to detect faults in a body has a handheld D-type battery flashlight configuration with a casing having a handle at one end and a flared lamp housing at the other. A reflector fits within the lamp housing, and a bulb rests in the reflector.

Abstract: In one embodiment, the present invention relates to a label containing a substrate layer, and a security coating on at least one side of the substrate layer containing: from about 50% to about 99.999% by weight of a film forming material, and from about 0.001 % to about 5% by weight of at least one taggant compound, wherein the taggant compound is substantially uniformly dispersed within the film forming material. In another embodiment, the present invention relates to a method of authenticating a product, involving: affixing a label to the product, the label containing a substrate layer, and a security coating on at least one side of the substrate layer containing: from about 50% to about 99.999% by weight of a film forming material, and from about 0.

Abstract: Apparatus and method for immobilizing molecules, particularly biomolecules such as DNA, RNA, proteins, lipids, carbohydrates, or hormones onto a substrate such as glass or silica; patterns of immobilization can be made resulting in addressable, discrete arrays of molecules on a substrate, having applications in bioelectronics, DNA hybridization assays, drug assays, etc.

Abstract: Extreme ultraviolet light (EUV) is detected using a precisely defined reference pattern formed over a shallow junction photodiode. The reference pattern is formed in an EUV absorber preferably comprising nickel or other material having EUV- and other spectral region attenuating characteristics. An EUV-transmissive energy filter is disposed between a passivation oxide layer of the photodiode and the EUV transmissive energy filter. The device is monolithically formed to provide robustness and compactness.

Abstract: An opto-electronic sensor for recognizing transparent articles, such as, for example, glass bodies, plastic bodies, or foils. The sensor includes at least one transmitter for transmitting light signals into a monitored region, at least one receiver for receiving the transmitted light signals, and at least one evaluation unit for the evaluation of the received signals. The transmitter is designed for the transmission of the light signals in the UV range. At least one reference transmitter is provided for the transmission of light signals into the monitored region. The light signals transmitted by the reference transmitter lie in a different frequency range from the light signals transmitted by the transmitter.

Abstract: A semiconductor imaging system preferably having an active pixel sensor array compatible with a CMOS fabrication process. Color-filtering elements such as polymer filters and wavelength-converting phosphors can be integrated with the image sensor.

Abstract: A method of superficial laser induced fluorescence for measuring film cooling performance within a fluid tunnel apparatus includes the step of introducing a test fluid uniformly dyed with a fluorescent dye into the fluid tunnel apparatus so as to surround a cooling model having a test geometry. The cooling model is positioned adjacent to a laser sheet. A background fluorescent image of the test fluid about the cooling model is recorded. The test fluid is then flushed from the tunnel apparatus. Next, a cooling simulation fluid flow and a hot gas simulation flow are introduced within the fluid tunnel apparatus. The cooling simulation fluid contains the same fluorescent dye concentration as the test fluid and the hot gas simulation fluid contains no fluorescent dye. A data image of the cooling simulation fluid flow is recorded about the cooling model as the cooling simulation fluid flow passes through the cooling model and into the hot gas simulation fluid flow.

Abstract: A release agent is first applied to a target article and on top of the release agent is applied an ultraviolet radiation fluorescent material to enable fraud detection. To prevent fraud, a security label may also be used comprising a label substrate, a release layer, a layer of ultraviolet radiation fluorescent material, and an adhesive layer for adhering to a target article. When the substrate is peeled off, part of the ultraviolet sensitive material will be peeled off also to enable detection.

Abstract: This invention provides for a fiber optic moisture sensor. The sensor is comprised of a housing and a support positioned within the housing. The support is coated with a film. A first and second light guides are positioned within the housing and communicate illumination to and from the film. A reflective surface is positioned within the housing facing the film. The film comprises an optically transparent polymer and a salt complex of a metal ion and an organic compound. The salt complex is capable of absorbing moisture and emits a fluorescence signal when excited by light at the appropriate wavelength. The fluorescence signal can be quenched when the salt complex absorbs moisture. An apparatus incorporating the sensor and a method of making the sensor are also provided.

Abstract: An injection system and method for blending an additive into a main fluid flow stream at a controlled ratio, characterized by a controller wherein the electrical circuitry thereof is contained in an explosion-proof housing having a window through which electromagnetic energy, such as an infrared command signal, can be transmitted. The circuitry contained within the explosion-proof housing includes a receiver for receiving the electromagnetic energy transmitted through the window and a processor or processors for decoding information included in the electromagnetic energy and for carrying out one or more functions based on such information. Also disclosed is an additive injection correction technique, a clean line technique and related and other features of the system and method.

Abstract: A low-cost, reference grade pyranometer responsive to radiation in a band such as ultraviolet-B embodies unexpected and efficient construction. Large arrays or other multisensor systems are consequently available to a greater range of users. A dome constructed of UV-transmissive material has mounted therein a UV-pass "black glass" filter which transmits UV-B to a phosphor layer. The phosphor absorbs UV-B and re-emits it as predominantly green visible light. A green filter, which is "solar blind," i.e. non-transmissive to reds in the solar spectrum, transmits light to a solid state photodiode. The solid state photodiode has peak sensitivity in the green portion of the spectrum and rejects substantially all red leakage. Critical parameters such as the density and thickness of the phosphor and temperature compensation of the pyranometer combine to provide for a simplified pyranometer having great precision in measuring bands such as UV-B compared to the prior art.

Abstract: Disclosed is a novel microscope slide. The slide of this invention is a plastic microscope slide which is optically opaque and substantially non-fluorescent. The slide of this invention has particular utility in epi-fluorescent microscopy.

Abstract: The invention relates to the technical field of chemical reaction.The apparatus of chemical reaction by wet process according to the invention is characterized in that the stack is at least partly constituted by a perforated envelope forming a barrier against the propagation of microwaves.The invention finds an application in mineralization.

Abstract: A device for scanning a linear section of a UV beam to determine the local intensity thereof along the linear section. The UV beam impinges upon flourescent material and the fluorescent emission distribution is meausred to indicate the UV beam intensity.

Abstract: A beam intensity profilometer produces a fluorescent emission distribution having a spatial distribution linearly proportional to the local intensity of an incident UV beam shined into the profilometer. The spatial distribution of the UV beam is analyzed and displayed as a function of the fluorescent emission.

Abstract: An ultraviolet radiometer converts UV radiation to fluorescent radiation. An optical signal corresponding to the intensity of detected fluorescent radiation is converted to an electrical signal corresponding to the power or energy of the detected fluorescent emission. A monitoring element receives the electrical signal and monitors the power or energy of the UV radiation.

Abstract: An optical waveguide with one or more coatings of reactants specific to species to be analyzed in a liquid analyte immersed therein. A light signal carried by the waveguide undergoes interaction either with the bulk analyte whereby a first signal in connection with the bulk analyte is obtained and, simultaneously, with a layer of complex resulting from the reaction of one of said specific reactant with one of said species or with two or more complex layers corresponding to two or more of said species, this generating a second (or more) signal to provide the required analytical information on said species.

Abstract: The unit consists of a cuvette and light guiding means comporting more than one waveguide element in contact with the solution to be analyzed. During operation, signals issuing from said waveguide elements provide data on two or more parameters in the solution substantially simultaneously.

Abstract: An arrangement for the fluorescence-optical measurement of concentrations of substances contained in a sample includes a detector, a light source and a sensor element that includes a carrier element, the carrier element having an indicator layer on a portion thereof and an indicator-free surface, the carrier element being transparent to the radiation used, and having a refractive index which is greater than that of the ambient medium at the indicator-free surface, the light space being positioned such that the transmission of light from the light source to the indicator layer, and from there to the detector, is achieved, at least partially, by total reflection in the carrier element.

Abstract: A method and apparatus for indicating quench associated with a liquid scintillation solution wherein the solution includes a sample, a solvent and a solute. The method includes exposing the solution to flashes of light, detecting a pulse height spectrum for scintillations produced in the solution in response to the light flashes, determining a unique point on such pulse height spectrum, and relating the unique point to a corresponding pulse height value, such pulse height value providing an indication of quench associated with the solution. The wavelength of light preferably excites essentially only the solvent and the light flash intensity and duration is such that the pulse height spectrum produced in response to the light flashes does not overlap a pulse height spectrum for the sample in the solution. An attribute of the shape of the light pulse height spectrum may be examined to provide an indication of the homogeneous or non-homogeneous nature of the quench present in the solution.

Abstract: A method and apparatus for fluorescent immunoassay utilizes total internal reflection at the interface between a solid phase and a liquid phase of lower index of refraction to produce an evanescent wave in the liquid phase. The solid phase is arranged and illuminated so as to provide multiple total internal reflections at the interface. In a preferred embodiment, the solid phase is in the form of an optical fiber to which is immobilized a component of the complex formed in the immunochemical reaction. A fluorophore is attached to another component of the complex. The fluorescent labelled component may be either the complement to or an analog of the immobilized component, depending on whether competitive or sandwich assays are to be performed. In the case of competitive assays, the labelled component is preferably pre-loaded to the immobilized component in a controlled concentration. The fiber (and the attached constituent of the assay) is immersed in the liquid phase sample.

Abstract: An assay apparatus and methods employing total internal fluorescence to define a thin observed volume of a multi-phase suspension from which the suspended phase, because of its size and shape, is substantially excluded. Observations of the fluorescence of a known quantity of fluorescent material introduced into a known volume of the sample containing the observed volume permits quantitation of the volumes of the suspended and suspending phases.

Abstract: Security papers with luminescing authenticity features worked into them or printed on them. The authenticity features used consist of a luminophore and one or more absorbing materials by which the emission and/or the excitation spectrum of the luminophore is changed in detectable fashion. The dyestuff can be present as an admixture to the luminophore, as a coating of a luminophore layer or as a coating on luminophore powder grains. For checking the authenticity of documents the emission spectrum of the luminophore is not used but the change generated by the technology used in the emission or excitation spectra.

Abstract: Fluorescent immunoassay apparatus and method employing a disposable consisting, in a preferred embodiment, of a short length of precise diameter capillary tubing having an axially disposed optical fiber to which is immobilized a monolayer of a component of the antibody-antigen complex (e.g., an antibody), an inert diluent, and a preload of a known amount of tagged complement to the immobilized component (e.g., a fluorescent-tagged antigen). The dimensions of the fiber and the capillary tubing are chosen so as to allow the tube to fill itself by capillary action once an end of the tube is immersed into the sample. Precise timing and ballistic measurements may, if desired, be avoided by insuring the incubation time is larger than the diffusion time necessary to scavenge the volume between the fiber and the capillary tubing. Fluorimetric measurement is made by total reflection fluorescence techniques.

Abstract: A method for increasing resistance to treeing in a polymeric layer comprising an insulating layer on a metal conductor. Pellets of an organic polymeric material also containing an organo silane treeing inhibitor are exposed to ultraviolet radiation, and pellets having portions fluorescing above a predetermined threshold level are separated from the remainder. The remaining pellets are blended together and applied to a metal conductor to form a coating on the conductor. In a preferred embodiment, the organic polymeric material is high molecular weight polyethylene, and the ultraviolet radiation has a wavelength of about 3000 to 4000 A.

Abstract: A new family of fluorescent antibodies (FAB) and a method for their synthesis is disclosed for use in an apparatus and method wherein the effects of background fluorescence are virtually eliminated from fluorescence measurements. The novel fluorescent antibodies consist of antibodies conjugated with rare-earth chelates which have unique fluorescent properties. These fluorescent antibodies are useful because when excited with short pulses of light, they exhibit fluorescent decay times which are much longer than typical background fluorescence at room temperature and with a spectral width far narrower than typical background fluorescence.

Abstract: In apparatus for examining the material of a specimen with local resolution employing an X-ray probe and operating according to the scanning principle, including a source of X-ray radiation, an optical system for directing X-ray radiation from the source onto the specimen, and a detector disposed for detecting radiation appearing behind the specimen, the source is constituted by a target in which the X-ray radiation is generated, and the optical system acts to focus the X-ray radiation emanating from the target onto the specimen in the form of an X-ray probe.

Abstract: A method of and apparatus for inspecting the threads of tubular elements for flaws, cracks and the like are disclosed. The invention is particularly useful in performing thread inspections of the box and pin ends of drill collars according to known processes using a fluorescent solution and ultraviolet radiant energy. An inspection unit is provided which encloses the threads to be inspected in a light-excluding manner and houses a source of ultraviolet energy. The threads are visually inspected through an aperture in the inspection unit by either rotating the inspection unit or the tubular element to be inspected.

Abstract: Nahcolite-containing ore particles are separated from oil shale particles in a mixture of particles of nahcolite-bearing oil shale ore by irradiating the mixture of ore particles with electromagnetic energy in the infrared region of the spectrum and sorting the particles according to energy reflected at one or more selected wavelengths within that region to separate the nahcolite-containing ore particles from the oil shale particles.

Abstract: A metal-covered substrate is first adsorbed with a layer of known biological particles. This active substrate is then put into a solution containing an unknown amount of second biological particles that will bind the first kind of particles which are randomly distributed in the layer. A third biological particle bound to a fluorescent dye is applied to this substrate which is then placed in an apparatus having a light source inducing fluorescent emission, and a photon counting system to measure the amount of fluorescent photon. The metal-covered substrate reflects the exciting photon toward a photon trap so that few exciting photons will go to the photon counting system, while the induced signal is reflected toward the photon counting system and more induced signal will be measured.

Abstract: A display process for the optical presentation of information which process omprises impinging laser beams modulated as to their direction, intensity and/or frequency, upon a transparent target containing a fluorescent substance which is excited by said laser beams to optical fluorescence, e.g., which absorbs in the ultraviolet range and yields fluorescent radiation in the visible range; typical ions capable of fluorescence are uranyl ions or ions of the rare earth elements.

Abstract: Apparatus for the detection and analysis of particulate material carried in a fluid stream comprising a sampling device through which the fluid stream may be passed, said sampling device incorporating means for arresting and carrying an accumulation of particles restrained from flow in the fluid stream, means for directing ultra-violet radiation onto the sampling device at a location where the accumulation of particles results, and means whereby optical radiation analysis may be performed of the radiation emitted by the accumulation of particles consequent upon their excitation by the ultra-violet radiation means.

Abstract: A data card wherein various data are recorded with a fluorescent material which emits infrared rays when excited by infrared rays is disclosed.The data card according to this invention has such merit that it is very effective for the preservation of secrecy and the prevention of forgery, that it is not affected by stains, that different information can be recorded thereon one over the other, and that it can be read by an extraordinarily compact reader.

Abstract: The paper carries, at one or more points, materials which, in the excited condition, fluoresce in the visible, ultraviolet, or infra-red spectral range in the characteristic emission spectra. The device includes a light source for exciting fluorescent substances, a condenser lens concentrating the light emitted by the paper, a narrow band interference filter, a focusing lens, and a series of photocells arranged in the focal plane of the focusing lens. The geometric arrangement of the photocells is chosen appropriately to identify an emission-line doublet. The outputs of the photocells are fed to a pre-amplifier and then to a comparator which may effect a subtraction of the amplified photocell output to provide an output signal. In a variation, the quotient of the photocurrents of two photocells is compared to establish the authenticity of the paper.

Abstract: A body suitable for use in the quantitative detection of an unknown quantity of a biologically derived sample suitably by radioimmunoassay, fluorometric detection, or by spectrophotometry. The body includes a handle attached to a nonparticulate, nonswellable, impermeable continuous surface region. A diagnostic reagent (e.g., an antibody) is covalently attached to the surface region. The surface region is stirred by the handle in a solution of sample substance (e.g., antigen) for reaction with the diagnostic reagent. In a competitive binding technique, a labelled substance (e.g., fluorochrome labelled antigen) is simultaneously contacted with the sample. Thereafter, the surface region is washed, and the label is measured as by a fluorometer. The technique is also applicable to the so-called "sandwich technique" in which the labelled substance (e.g., labelled antibody) is reacted with the sample substance after it has been reacted with the diagnostic reagent.

Abstract: In the method, light from an ultraviolet light source is directed alternately through a neutral filter, uniformly damping the radiation of the light source, and through a partially absorbing filter damping only the wavelengths necessary to excite the fluorescence of a selected flourescent material, the partially absorbing light filter including the selected fluorescent material. The light passing through the filters is then directed through a first blocking filter onto a sample to be checked for the presence of a selected fluorescent material. Only the radiation from the sample is directed through a second blocking filter onto a photodetector or the like. The respective intensities of radiation of the sample, effected by the neutral filter and by the partially absorbent filter, are measured and converted into output signals indicative of the presence or absence of the selected fluorescent material.

Abstract: An ultraviolet liquid purification system includes a purification chamber having banks of ultraviolet lamps distributed therein for applying germicidal ultraviolet radiation to the liquid flowing through in said chamber. Ultraviolet photocell detectors are located in said chamber to detect the level of ultraviolet radiation transmitted through the quartz jacket housing the ultraviolet lamps and through the liquid being purified. Indicator means produce an alarm signal when the total ultraviolet radiation transmitted through the liquid drops below a preselected level. In addition, a light conducting fiber is provided for each ultraviolet lamp having its input endface located at the ultraviolet lamp and its output endface at a display panel whereby identification of a particular ultraviolet lamp that has failed may be easily detected. Photocell detector means are provided to detect the light output at the output endface of the light conductor fiber and to produce an alarm signal when said light output fails.

Abstract: An improved electrostatic electron lens for photoelectron emission microscopes is disclosed, having a planar upper surface on its beam entrance electrode highly polished to a mirror finish for light reflection. The lens is positioned between a light source and a specimen holder such that light may be reflected off the planar upper surface of the entrance electrode onto the specimen for causing photoemission of electrons from such specimen. The lens is constructed to enable expansion of the lens electrodes during heating, such as "bake-out" to remove adsorbed gases, without breaking the insulators between such electrodes. An intermediate electrode is disposed in a spaced, insulated relationship between the beam entrance electrode and an exit electrode by two insulator members.

Abstract: A fluoroescence spectrometer or fluorometer for simultaneously presenting the excitation and emission spectra of a multicomponent sample in the form of an intensity matrix is disclosed which comprises an elongated cuvette for holding the fluoroescent sample, along whose length a spatially distributed spectrum of exciting energies is simultaneously directed, and a polychromatic analyzer which simultaneously analyzes the excitation and emission spectra given off by the sample along its length by producing a spectrally dispersed image of the cuvette. The matrix of spectral intensities so obtained may be converted to electrical signals by a low-light-level television detector and displayed on a video monitor or processed with appropriate analog or digital computers for immediate analysis. The instrument can acquire 241 emission spectra taken at 241 different exciting wavelengths in 16.7 milliseconds.

Abstract: A sign having phosphorescent indicia, a light source providing ultraviolet radiation for illuminating the sign and charging the phosphorescent indicia, and a photoelectric sensor responsive to the level of the phosphorescent glow of the indicia for briefly energizing or flashing the light source whereby to effectively recharge the phosphor when the light level of the glow decays below a predetermined value.

Abstract: The present invention contemplates an arrangement for analyzing a plurality of components in a single specimen which comprises placing a diluted specimen into a storage cup which is part of a sample carrier system, containing storage and reaction cups, transferring aliquots of the diluted solutions of the sample from the storage to the reaction cups, presenting the rows of the reaction cups to a work station, sequentially, adding a reagent to each of the reaction cups and moving the reaction cups into a work field where beams of light passing through the various reaction cups can be scanned and the components contained in the reaction cups can be assayed by means of a single detector attached to a computer and print-out system.

Abstract: A method of measuring mechanical damage to a grain, such as corn, includes applying a reacting solution to a sample of corn. The solution contains a material, such as 8-anilino-1-naphthalene sulfonic acid, that reacts selectively with the damaged portion of the corn kernels, i.e., the internal protein that is exposed when the outer shell is penetrated or breached. Excess solution is washed off; and the kernels are dried for convenience of handling. The dried corn is ground to a uniform fineness and then spread over a predetermined area. What is inherently a three-dimensional or volume phenomena (damage) is converted to a two-dimensional or area measurement. The sample is exposed to ultraviolet light; and induced fluorescence is measured. The output of the measuring system is linearly related to, and thus a measure of the mechanical damage of the sample.

Abstract: A fluorometric system to determine the kind and amount of substances derived from a biological fluid (e.g., serum or urine) or tissue. The substances to be detected (e.g., antigen, antibody, hormone or enzyme) is coated onto a substrate in fluorescent form. Multiple coating areas of different samples may be employed. The fluorometric system includes a source of light to excite fluorescence, a fiber optic cable to conduct the excitation light to such coating, and a second fiber optic cable to conduct emitted fluorescence to a detector device. The system minimizes any gap distance in the path from the sample to the detector which permits the loss of excessive fluorescence. A branched fiber optical cable with the main trunk terminating adjacent the sample with one branch for transmitting light to the sample and the other for transmitting fluorescence light to the detector.

Abstract: A spectrofluorimeter for measuring excitation and emission spectra uses a flash or pulsed light source, an excitation monochrometer adjustable by a stepping motor, a first optical system for directing radiation onto a sample under test, a reference light detector for monitoring the excitation radiation, an emission monochrometer, also adjustable by a stepping motor, for receiving radiation via a second optical system from the sample and directing selected wavelengths to a detection photomultiplier, the first and second optical systems being corrected for spherical and chromatic alterations.

Abstract: An apparatus for enabling the tolerance of the skin of individual persons to ultra-violet radiation to be determined, including a source of UV radiation and a mask having apertures for allowing UV radiation of different intensities to be applied to the skin of a person being tested.

Abstract: An apparatus for detecting the presence in a liquid of material that emits fluorescent radiation when stimulated by ultraviolet radiation. A chamber having an inlet and an outlet for passing a stream of liquid therethrough. A source of ultraviolet radiation associated with said chamber with means for energizing same whereby said radiation may pass to said stream and a receiver arranged to receive fluorescent radiation emitted by such a stream.

Abstract: Receptors are employed to which one or more fluroescent molecules are bound. When the receptors are bound to the epitopic sites on the surface and light of predetermined wave length is directed toward the surface, the fluorescing molecules are activated and fluoresce.In carrying out an assay, receptor is combined with an unknown suspected of containing molecules having the same epitopic sites bound to the surface. The receptor will bind to these molecules reducing the number of receptor sites available for binding to the epitopic sites on the surface. When the assay medium is contacted with the surface, the amount of receptor which binds to the surface, will be a function of available binding sites and, therefore, to the number of the molecules present in the unknown. Upon irradiation of the surface, substantially only the fluoroescent molecules bound to the surface will fluoresce. By monitoring the fluorescence, one can determine the presence and number of molecules of interest present in the unknown.

Abstract: An improved spectrophotometer of the non-dispersive absorption type useful for detecting the presence of SO.sub.2 in a gaseous sample, despite the simultaneous presence of NO.sub.2. Ultraviolet light from a commercially-available source impinges upon a fixed phosphor screen which fluoresces to produce ultraviolet radiation at a first wavelength, at which both SO.sub.2 and NO.sub.2 absorb radiation; and at a second wavelength at which absorption by SO.sub.2 is minimal but NO.sub.2 absorption is approximately the same as at the first wavelength. The radiation is directed through a sample chamber having windows which are transversely slidable to effect cleaning without destroying the integrity of the chamber seal, then introduced into an envelope enclosing filters and a pair of photosensors. One photosensor receives light at the second wavelength and produces a signal which reflects the attenuation by NO.sub.2 at that wavelength.

Abstract: An ultraviolet liquid purification system includes a purification chamber having banks of ultraviolet lamps distributed therein for applying germicidal ultraviolet radiation to the liquid flowing through in said chamber. Ultraviolet photocell detectors are located in said chamber to detect the level of ultraviolet radiation transmitted through the quartz jacket housing the ultraviolet lamps and through the liquid being purified. Indicator means produce an alarm signal when the total ultraviolet radiation transmitted through the liquid drops below a preselected level. In addition, a light conducting fiber is provided for each ultraviolet lamp having its input endface located at the ultraviolet lamp and its output endface at a display panel whereby identification of a particular ultraviolet lamp that has failed may be easily detected. Photocell detector means are provided to detect the light output at the output endface of the light conductor fiber and to produce an alarm signal when said light output fails.