Showing papers on "Parabolic reflector published in 1994"

Tailored edge-ray reflectors for illumination

Abstract: The edge-ray principle can be used to tailor a reflector. However, one set of edge rays already fully determines the reflector profile. We present a design method for tailoring compact compound elliptical concentrator (CEC)-type reflectors to a given source and a desired angular power distribution. Two reflected images of the source, one on each side of the source, contribute together with the direct radiation from the source to produce the desired power distribution. We determine the reflector profile by numerically solving a differential equation. No optimization is required. Beyond the angular region in which the power distribution can be strictly controlled, the power drops to zero in a finite decay range. This decay range becomes narrower as the reflector increases in size. We show a reflector for producing a strictly constant irradiance from −43 to 43 deg from a cylindrical source of constant brightness. The reflector extends to a maximum distance of 8 source diameters. No power is radiated beyond ± 50 deg.

A broadband free-space millimeter-wave vector transmission measurement system

Abstract: We report both broadband monolithic transmitter and receiver IC's for MM-wave electromagnetic measurements. The IC's use a nonlinear transmission line (NLTL) and a sampling circuit as a picosecond pulse generator and detector. The pulses are radiated and received by planar monolithic bow-tie antennas, collimated with silicon substrate lenses and off-axis parabolic reflectors. Through Fourier transformation of the received pulse, accurate 30-250 GHz free space gain-frequency and phase-frequency measurements are demonstrated. Systems design considerations are discussed, and a variety of MM-wave broadband transmission measurements are demonstrated. >

Vehicular headlamp having uniform appearance

Abstract: A vehicular headlamp which has a good uniformity of design and a good appearance when viewed from the front. A first lamp of the reflection type having a light source and a parabolic reflector circular when viewed from the front, and second and third lamps of the projection type having light sources, substantially elliptic reflectors, and projection lenses circular when viewed from the front, are horizontally arrayed. Profile lines, circular when seen from the front, are formed on a transparent front cover assembled over the front opening portion of the lamp body at positions corresponding to the three lamps and matching the circumferential profiles of the reflector or the projection lenses, whereby a horizontal array of the three profile lines appears in the front cover, providing the headlamp with a good uniformity of design.

Metallized mesh fabric panel construction for RF reflector

Abstract: A metallized mesh fabric construction for use as the individual reflector panels of a radio frequency (RF) deployable parabolic reflector of the type which includes a plurality of panel supporting rib members which, upon deployment, unfurl in a spiral manner from a central hub to form the parabolic reflector surface. The mesh fabric includes silver coated nylon strands and stretch resistant plastic or synthetic strands interwoven in a "Marquisette" or "Leno" style weave. The stretch resistant strands of the mesh fabric are oriented along the chordal direction (i.e., transverse to the radial direction of the unfurlable ribs) in order to withstand the tension placed on the mesh fabric during deployment of the reflector and hence maintain the shape and accuracy of the reflector surface and resist creep. The weave has openings sized sufficiently large to minimize the effects of wind load yet sufficiently small to provide good reflective performance of radio frequencies up to and including X-Band frequencies.

Double reflection cathodoluminescence detector with extremely high discrimination against backscattered electrons

Abstract: A parabolic reflector and an inclined planar light reflector in a cathodoluminescence detector are integrated with a set of photo-sensitive solid-state detector cells mounted in quadrature on a supporting plate, and supported by an electron microscope vacuum chamber specimen stage adaptor unit. Designed for CL emission operation in an electron microscope, the parabolic light reflector, the inclined planar light reflector and the photo-sensitive, solid-state detector cells are optically aligned and mechanically combined through the supporting plate of the detector cells. A readily exchangeable unit is thus obtained. The unit is further supported by the specimen stage adaptor unit so as to obtain a mechanical unit which can easily be mounted in and removed from any standard electron microscope vacuum chamber stage as a single integrated unit.

Difference dispersive double-path monochromator having wavelength-independent imaging point

Abstract: Incoming light is reflected by a first parabolic mirror for incidence as parallel rays of light on a diffraction grating, the reflected light therefrom is incident on a second parabolic mirror, and the reflected light therefrom is bent by first and second reflecting mirror in a vertical direction and reflected back to the second parabolic mirror, from which it is reflected to the diffraction grating. The reflected light from the grating is reflected again by the first parabolic mirror for incidence on a photodetector. An optical glass plate is inserted in the optical path between the second reflecting mirror and the second parabolic mirror. By the passage through the optical glass plate, the optical axis in a horizontal plane is displaced to ensure the incidence of light from the first parabolic mirror on the photodetector regardless of the wavelength of the incoming light to be measured.

Instrument probe having a back-lighted camera

Abstract: An instrument probe (10) contains an improved camera and light source arrangement. The light source (18) is positioned behind the camera (22) for providing indirect illumination of a passage being inspected by the camera (22) such as the contents of a bore hole (28) or its casing (36). The light source (18) is physically separated from the camera (22) thus providing insulation to the camera (22) from heat produced by the light source (18). The camera housing comprises a quick connect and disconnect latch (60) which allows for the swift changeover of camera components at the distal end of the instrument probe (10). A parabolic reflector (34) at the light source directs light distally to the instrument body (10). A second reflector (58) is located on the camera body to further reflect light towards the walls of the passageways, thereby enhancing the indirect light funneled to the area being inspected by the camera (22).

Numerical and Experimental Analyses of the Radiant Heat Flux Produced by Quartz Heating Systems

Abstract: A method is developed for predicting the radiant heat flux distribution produced by tungsten filament, tubular fused-quartz envelope heating systems with reflectors. The method is an application of Monte Carlo simulation, which takes the form of a random walk or ray tracing scheme. The method is applied to four systems of increasing complexity, including a single lamp without a reflector, a single lamp with a flat reflector, a single lamp with a parabolic reflector, and up to six lamps in a six-lamp contoured-reflector heating unit. The application of the Monte Carlo method to the simulation of the thermal radiation generated by these systems is discussed. The procedures for numerical implementation are also presented. Experiments were conducted to study thesebreak quartz heating systems and to acquire measurements of the corresponding empirical heat flux distributions for correlation with analysis. The experiments were conducted such that several complicating factors could be isolated and studied sequentially. Comparisons of the experimental results with analysis are presented and discussed. Good agreement between the experimental and simulated results was obtained in all cases. This study shows that this method can be used to analyze very complicated quartz heating systems and can account for factors such as spectral properties, specular reflection from curved surfaces, source enhancement due to reflectors and/or adjacent sources, and interaction with a participating medium in a straightforward manner.

Optical reflector, illumination optical system, light source system and illumination optical apparatus

Abstract: An optical illumination system according to the present invention is provided with an optical reflector for illuminating a surface to be illuminated in the shape of arc or annulus. A reflective plane of the optical reflector is shaped in a special curved surface. Specifically, an arbitrary parabola with a first axis passing through the vertex and the focus of the parabola is rotated about a second axis passing through a point located on the opposite side of the directrix of the parabola with respect to the focus and being parallel to the directrix. The rotation of the parabola yields a parabolic toric surface. The reflective plane of the optical reflector has the curved surface constituting at least a part of the parabolic toric surface. The reflective plane so shaped reflects a light source image emitted from a light source system to illuminate the surface to be illuminated in the shape of arc or annulus.

Helmet mounted off axis liquid crystal display with a fiber optic wedge and a curved reflector

Abstract: An optical arrangement that provides a telecentric helmet mounted display optical system. The optical arrangement comprises an image source including a faceplate wedge attached to a liquid crystal display, such as an active matrix liquid crystal display, for example, that is illuminated with collimated fight. The output image is used as a light source for an off-axis or on-axis reflector used to produce an output image. The faceplate wedge corrects the anamorphic distortion exhibited in the off-axis reflector and directs the light energy into the off-axis entrance pupil of the reflector to maintain high uniformity over the exit pupil without sacrificing brightness. More particularly, the present invention comprises the input light source, and the liquid crystal display that is illuminated with collimated light from the light source. The faceplate wedge is optically coupled to the liquid crystal display, and the reflector is optically coupled to the faceplate wedge for producing an output image. The faceplate wedge corrects for anamorphic distortion exhibited in the reflector and directs light energy into an off-axis entrance pupil to maintain high uniformity over the exit pupil without sacrificing brightness. The reflector may comprise an off-axis or on-axis portion of a parabolic reflector. The optical arrangement may further comprise a collimating lens disposed between the liquid crystal display and the input light source. The collimating lens may comprise a Fresnel lens. In an off-axis version, the optical arrangement may further comprise first and second planar reflectors disposed between the input light source and the collimating lens, and a negative lens optically coupled to an output surface of the faceplate wedge. In an on-axis version, the optical arrangement may further comprise a beamsplitter optically coupled between the faceplate wedge and the reflector.

Multiple port high brightness centralized lighting system

Abstract: A centralized lighting system having a plurality of output ports includes a high brightness light source disposed at the optical focal point of a parabolic reflector. The light source and reflector configuration deliver light output in an essentially parallel manner to a plurality of lens members effective for focussing the light output into a plurality of spatially separate light spots. The spatially separate light spots are input to optical fibers without experiencing packing fraction losses. The plurality of lens members are disposed equidistantly along radii formed relative to the reflector but at a spaced apart relation to the reflector. In this manner, the lens members provide the spatially separate light spots which are essentially equal in terms of color and intensity to one another.

Indicating lamp for vehicle

Abstract: PURPOSE: To prevent fluctuation in efficiency due to thickness and change in characteristics due to head by providing a mirror formed by stacking a hologram on the bulb side of a plane reflecting mirror to be as a volume transfer type hologram which wave-front converts direct light from a filament to have wave front and angle diffracted by the indicating hologram and forcing the light to enter. CONSTITUTION: Some of light emitted from a filament 2 that is not reflected by a parabolic mirror 3, but directly transmits a colored filter 4 to become an indicating color and reaches a wave front converting mirror 5 becomes a spherical wave L1 centering around the filament 2. A wave front converting hologram converts a spherical wave L1 of an indicating color to a diffracted plane wave having wave front and angle diffracted by an indicating hologram 6, and the plane wave is again diffracted by the indicating hologram 6 and transmitted through a light transmitting plate 8 to be emitted as an indicating light to the outside. At this time, diffusional property is given to the transmitted indicating light by micro-lens like projecting and recessed parts 8a provided on the inner surface of the light transmitting plate 8 so as to visually confirm the indicating light in a further wider angle range.

Laser beam machine

Abstract: PURPOSE:To provide a laser beam machine excellent in a converging characteristic by easily and highly precisely performing the alignment of a parabolic mirror. CONSTITUTION:The laser beam machine is constituted so that a laser beam from a laser oscillator 7 is transmitted to a converging mirror unit l through the plane mirrors 8, 9 and 10, is led to an internal parabolic mirror 2, and is converged at the outlet of a working nozzle. For the alignment of the parabolic mirror 2, the first center jig 5 is arranged at the inlet of the converging mirror unit, the second center jig 6 is arranged on an optical axis from the laser oscillator to the converging mirror unit, and the optical axis of a laser beam is adjusted. Also, a total reflection mirror is installed instead of the working nozzle, and an adjustment is made by the first center jig 5 and the second center jig 6 with reflected light. In this way, an alignment is performed at higher accuracy, and a laser beam device excellent in a converging characteristic is obtained.

Method for sterilizing cartons

Abstract: An ultraviolet (I/V) sterilization system for food cartons is disclosed. An elongated UV lamp is mounted in a housing. A parabolic cylinder reflector is mounted in the housing with the focus of the reflector coinciding with the axis of the arc in the UV lamp. The shape of the parabolic reflector directs radiation from the lamp into cartons positioned on a conveyor below the lamp. The axis of the arc is parallel to the direction of movement of the cartons on the conveyor. The front surface of the reflector also absorbs heat from the lamp and heat is removed from the reflector by circulating air over the back surface of the reflector.

Method of manufacturing a opto-electronic component with narrow aperture angle

Abstract: The invention relates to an opto-electronic component having a narrow aperture angle. The conventional design of components transmitting radiation or reacting to radiation and concentrating that radiation with the aid of lenses results, on account of the increasing distance between the lens and the semiconductor chip, in increasing component dimensions in the radiating or detecting direction with an increasingly narrow aperture angle. In accordance with the invention, a parabolic or approximately parabolic reflector is provided that is connected to a support strip supporting the semiconductor chip such that the latter is as close as possible to the focal point of the parabolic or approximately parabolic surface of the reflector. The reflector is preferably connected to the support strip by engaging elements and surrounded by a housing.

Optical radio transmitter-receiver and optical radio equipment and optical axis adjusting method for the equipment

Abstract: PURPOSE:To prevent interference to realize long distance transmission even at the time of using plural systems using an LED in parallel, to directly transmit a signal such as a Manchester code by radio, and to provide an effective and convenient optical axis adjusting method CONSTITUTION:An LED 12 is arranged at the focus position of a parabola reflector 11 of a transmitter 10 or the neighborhood of the focusing position, and the outgoing light of the LED 12 is reflected by the reflecting surface of the paradolic reflector 11 so as to be a parallel light A pin photodiode 22 is arranged at the focus position of a parabolic reflector 21 of a receiver 20, and the light reflected by the parabola reflector 21 is converged to the focus position, and received by the pin photodiode 22 Also, an optical axis is adjusted by using an optical level detector, light emitter or light receiver whose directivity is wider than the transmitter 10 or the receiver 20, and constitution in which the two parabolic reflectors for transmission and reception are integrated or the like

Sound image visualizing device for sound source observation

Abstract: PURPOSE:To provide the sound source observation use sound image visualizing device by which a sound source is surely observed with simple configuration, the sound image is visualized and which is used for maintenance of an observation object. CONSTITUTION:The system is provided with an observation object having a sound source, a parabolic reflector 1 opposed to the observation object, a microphone array 2 arranged to a focal plane of the parabolic reflector 1, and a display device converting a spatial distribution of sound pressure in front of the parabolic reflector 1 into a 2-dimension picture continuously based on an output signal of the microphone array 2.

Broadband Waveguide Feed for Parabolic Reflectors

Abstract: The broadband requirement in microwave systems has necessitated attention on components that can operate over frequency ranges far broader than those of standard rectangular waveguides. This paper describes the design and development of an ridged horn to match the waveguide impedance to freespace impedance so that the horn could be used as a feed for an offset-fed parabolic reflector over a wide band of frequencies, i.e., C and X bands (4.2 to 10.2 GHZ). In the present case, a five stepped chebyshev transformer has been used. Complete design required for horn feed as well for the ridged waveguide components necessary for testing has been carried out. The results obtained are quite encouraging. Good agreement is found between the measured results and theoretical values.

Microwave scattering from saline ice using plane wave illumination

Abstract: Radar systems used to generate ground truth data, for the scattering properties of distributed targets are generally operated in the near zone region of the antenna. These systems usually use antennas whose illumination of the distributed target contains a wide range of incidence angles. It is desired to measure the scattering properties of targets as a function of incidence angle which requires some type of inversion of the measured results. This problem can be overcome by applying the compact range antenna concept. A parabolic reflector with an offset feed effectively propagates a plane wave of uniform phase over an area approximately equal to the diameter of the reflector and at ranges up to about .5 * D/sup 2///spl lambda/, where D is the reflector diameter and /spl lambda/ is the wavelength. For the first time, this antenna concept has been used to study the scattering response of smooth, snow covered and rough saline ice grown under laboratory conditions. By coupling the compact range antenna with a wide-band (2 to 18 GHz) network analyzer based radar, the authors have achieved exceptional definition of the near normal scattering response of the ice surface and subsurface. This approach is likely to have broad utility in a variety of other geophysical applications including studying the scattering response of the ocean, soils and vegetation. >

Optically curably molding apparatus

Abstract: PURPOSE:To provide an optically curably molding apparatus which can accurately mold without increasing in size more than required the apparatus. CONSTITUTION:A light beam R1 incident from a light source 10 of an optically curably molding apparatus 2 through optical systems 12-18 is deflected in a perpendicular surface by a galvanomirror 24 placed at a focus 25 of a rotary parabolic mirror 22. Since light beams R3 passed through the focus 25 and reflected at points of the mirror 22 all become parallel to an axis V2 of the rotary parabolic surface due to properties of the parabolic surface, when a light beam R2 is deflected in a range of 90 degrees in a perpendicular surface by the galvanomirror 24, the beams R3 are emitted perpendicularly to a surface 32 of optically curable resin 30 in a light beam emitting range W1. Scanning in a Y-axis direction is conducted by moving the mirror 22 in the Y-axis direction by a Y-axis moving unit 28. A distance from the focus 25 to a vertex 22a of a parabolic curve becomes a half of a distance from the focus 25 to a perpendicular line V1, and a height of the apparatus becomes a necessary minimum limit.

Device for display at head height

Abstract: The invention provides a device for display at head height for use in a motor vehicle, which allows image information to be presented at a remote location and in which a height offset of a double image and a distortion of the double image, which are caused by the curved shape of the vehicle windscreen, are largely avoided. In this device, a projector (3) has a centre mirror (6) for reflecting image information such as characters or marks on to a reflective surface. The centre mirror contains an area (18) of a parabolic reflective surface, which is arranged at a distance from a main axis of a parabolic mirror. The said area of the parabolic reflective surface contains a first curved surface of low curvature, which coincides with the area of high curvature of the vehicle windscreen (2), and a second curved surface of high curvature which coincides with the area of the vehicle windscreen of low curvature, so that the distortion of the image information due to the differences in curvature of the vehicle windscreen and a height positional offset of a double image, which can occur when the image information is observed by both eyes (10, 11) of a person travelling in the motor vehicle, are corrected.

Head lamp for automobile

Abstract: PURPOSE:To provide the head lamp for automobile having the excellent visibility by using an arc tube as a light source. CONSTITUTION:A head lamp for automobile is provided with a parabolic reflector 11 and an arc tube 21 provided as a light source in a nearly focus position of the parabolic reflector 11, and the light emitted from the arc tube 21 is reflected forward for flux distribution through the parabolic reflector 11. The parabolic reflector 11 is arranged so that the reflecting surface thereof directs downward so as to reflect the light, which is emitted from the arc tube 21, downward. A mirror 24 for reflecting the light, which is reflected by the reflector 11, forward is provided under the parabolic reflector 11. The arc tube 21 is arranged so that the discharge axis passing the counter electrode of the arc tube 21 is directed in the horizontal direction nearly crossing the center axis L of the reflector 11 and that the arc of the arc tube 21 at the time of stabilized discharge is positioned at a position near the focus of the reflector 11 to form the image of an arc to be appeared in the flux distribution pattern under the electing condition and improve the (distance) visibility.

Elongated indoor light fixture for lighting a work station

Abstract: The strip lighting unit has a box-shaped housing (1) with a single lighting source (2) at the central point. The light output of the lamp is directed through channels for optimising the lighting distribution. The channels expand in cross-section and have parabolic reflector pairs (3) on both sides. The ends of the housing are completed by curved reflectors (5) and the underside of the top channel surface is also reflective (4).

Optical device for laser beam machining

Abstract: PURPOSE: To reduce the maintenance cost due to the pollution and breakage in achieving the laser beam machining by separating the multiple dividing function of the laser beam from the converging function to facilitate the manufacturing of individual optical parts such as a reflecting mirror and a converging lens and to reduce the cost. CONSTITUTION: The laser beam B1 emitted from a laser beam oscillator through a transmission system is multiply divided (two in the illustration) by a flat type reflecting mirror 3 within a machining head 1, and the respective laser beams b1 , b2 are reflected by another reflecting mirror 4 consisting of a single parabolic mirror to be converged to the focal points P1 , P2 distributed on a work W in the transverse direction. The reflecting mirror 3 consists of two semi-circular mirrors 3a, 3b capable of changing the inclination of the surface.

Vehicular headlamp providing near-ultraviolet radiation

Abstract: A vehicular headlamp that provides near-ultraviolet illumination of desired areas but which assures that sufficient brightness can be obtained in areas illuminated with visible light without having to combine the lamp with another type of headlamp. The headlamp includes a light-emitting unit accommodated in a lamp housing including a substantially parabolic reflector, a discharge bulb mounted inside the reflector to generate both visible light components and ultraviolet rays, and a light-emitting lens disposed in front of the reflector to irradiate the light reflected from the reflector in the forward direction. In addition, a bandpass filter adapted to absorptively remove visible light components and permit at least near-ultraviolet rays to pass therethrough is disposed in a light path other than the light path for the low-beam light conducted to the light emitting lens from the reflector so that a low-beam illuminating area is illuminated by both visible light components and near-ultraviolet rays to maintain sufficient brightness in the foregoing region. On the other hand, an illuminating area located above a clear cut line is illuminated mainly by the near-ultraviolet rays.

Transient axial solution for the reflection of a spherical wave from a paraboloidal mirror

Abstract: A method used previously [J. Acoust. Soc. Am. 93, 1256 (1993)] to derive a transient axial solution for a spherical wave reflected from an ellipsoidal mirror is applied to the case of a paraboloidal mirror. The incident spherical wave is radiated from the focus of the mirror. A solution for the impulse response of the reflected axial pressure is obtained in the form h(z,t)= δ(t−z/c0)−he(z)δ[t−te(z)]−(c0/zF)h w(z,t), where δ is the Dirac delta function, c0 is sound speed, z is axial distance from the base of the mirror, zF is distance to the focus, he is the relative amplitude of the edge wave, te its relative time of arrival, and hw is the wake. Simple expressions are obtained for he and hw. Beyond the focus, the geometrical acoustics result he∼(1+d/zF)−1 is recovered for the edge wave, where d is the mirror depth. In the far field, hw becomes a delta function, the impulse response reduces to h(z, t)∼(2z2F/c0z)ln(1+d/zF)δ’(t−z/c0), and the derivative of the source waveform is thus obtained. Calculations f...

Orientable antenna with maintenance of the polarisations axes

Abstract: The antenna of the invention is orientable, directional, and capable of operating either in transmission, or in reception, or both. The antenna comprises at least one reflector, at least one electromagnetic radiation source comprising means of exciting this source with two linear orthogonal polarisations, and mechanical means for positioning and maintaining the source and the reflector. According to the invention, the orientation of the antenna is broken down into aiming-off and rotation around a favoured direction of propagation of the radiation, and the mechanical means making it possible to effect this rotation while maintaining the source fixed, thus preserving the orientation of the linear orthogonal polarisation axes. In a preferred embodiment, the antenna of the invention comprises a main parabolic reflector and an auxiliary hyperbolic reflector arranged in a Cassegrain geometry, and the mechanical means make it possible to effect rotation of the two reflectors about the favoured direction of the radiation, while keeping the source fixed, thus preserving the linear orthogonal polarisation axes of the beam. Applications in radar, direct broadcast by satellite, and telecommunications by radio, with frequency reuse by polarisation diversity, which is particularly advantageous for space or airborne applications.

Method and apparatus for noncontact detection of edge part of object

Abstract: PURPOSE: To detect and evaluate a rim part of an object or a plurality of rim parts of an object in a non contact method. CONSTITUTION: A work face A is scanned by focused light beam, typically laser beam emitted from a light source L at 40-45 degrees. A first and a second detector D1, D2 receive reflected light from the work face A. The first detector D1 is installed behind a focusing imaging optical system O, e.g. off axis parabolic mirrors arranged coaxially, in other words all are arranged in the surrounding of laser beam, or under light beam emitted in relation to the main work face H. The second detector D is placed approximately on light spot formed by light emitted to the main work face. The stray light measured by the first detector D1 is received at a prescribed angle to the main work face and the angle is equal to the angle between the emitted light and the plane face or smaller than that.

Achieving uniform efficient illumination with multiple asymmetric compound parabolic luminaires

Abstract: Luminaire designs based on multiple asymmetric nonimaging compound parabolic reflectors are proposed for 2-D illumination applications that require highly uniform far-field illuminance, while ensuring maximal lighting efficiency and sharp angular cutoffs The new designs derive from recent advances in nonimaging secondary concentrators for line-focus solar collectors The light source is not treated as a single entity, but rather is divided into two or more separate adjoining sources An asymmetric compound parabolic luminaire is then designed around each half-source Attaining sharp cutoffs requires relatively large reflectors However, severe truncation of the reflectors renders these devices as compact as many conventional luminaires, at the penalty of a small fraction of the radiation being emitted outside the nominal cutoff The configurations that maximize the uniformity of far-field illuminance offer significant improvements in flux homogeneity relative to alternative designs to date