Showing papers on "Parabolic reflector published in 2011"

A High-Performance Dual-Mode Feed Horn for Parabolic Reflectors with a Stepped-Septum Polarizer in a Circular Waveguide [Antenna Designer's Notebook]

Abstract: This article describes a circularly polarized feed horn designed to feed shallow, prime-focus or offset-fed parabolic reflectors. Both circular polarization senses are available at two individual coaxial ports. The design provides good circularity, a very clean radiation pattern with excellent sidelobe suppression, outstanding isolation between ports, and needs no adjustments. An L-band example is presented, including both simulation and experimental results. The complete set of dimensions, not previously found in the literature for septum polarizers in circular waveguide, is provided for the practical engineer who desires to duplicate or scale this feed horn to other frequencies.

Light-based touch screen using elliptical and parabolic reflectors

Abstract: A touch screen system, including a housing, a display mounted in the housing, a plurality of light pulse emitters mounted in the housing below the display, a plurality of light pulse receivers mounted in the housing below the display, a first light guide, mounted in the housing along a first edge of the display, including a first substantially parabolic reflective surface for reflecting light pulses transmitted by the emitters, and a first substantially elliptical refractive surface, positioned substantially above the first substantially parabolic reflective surface, for refracting the reflected light pulses over the display, a second light guide, mounted in the housing along an opposite edge of the display, including a second substantially elliptical refractive surface for further refracting the light pulse refracted by the first substantially elliptical refractive surface, and a second substantially parabolic reflective surface, positioned substantially below the second substantially elliptical refractive surface, for reflecting the further refracted light pulses to the receivers, and a calculating unit, mounted in the housing and connected to the receivers, to determine a location of a pointer on the display that partially blocks the light pulses refracted by the first light guide, based on outputs of the receivers corresponding to light pulses refracted by the second light guide.

Wideband Beam-Steerable Flat Reflectors via Transformation Optics

Abstract: A conventional parabolic reflector is converted into a flat one based on the discrete coordinate transformation. Instead of general beam-steering techniques, such as off-axis feeding, tilting the feed/reflector, or utilizing phase shift, we show an alternative way to manipulate the reflected emission through tuning transformed dielectrics. The proposed design, only including the conventional dielectric components, has a merit of keeping the flat profile of a compact reflector system while possessing the ability to steer the radiation beams in a wide frequency band.

Lens design of LED searchlight of high brightness and distant spot

Abstract: The study related in this paper is the design of a ship-mounted LED of high brightness and distant spot. The freeform lens design obeying the edge ray principle and Snell’s law is presented first. Then, to fit the illumination requirement of the searchlight, we designed a freeform lens to collimate all the light rays coming from the LED. However, theoretical analysis proves that there is a critical angle for incident rays beyond which the rays cannot be collimated, and 55% is the light-efficiency limit for polymethyl methacrylate freeform lens. We then designed a combination of a freeform lens–coupled parabolic reflector that improved light efficiency to 70%. In this paper, the design of the freeform lens–coupled parabolic reflector is given in detail. In addition, tolerance analysis and the effect of manufacturing defect are presented.

L-Band Feed Horn and Orthogonal Mode Transducer for the KAT-7 Radio Telescope

Abstract: The design, simulation and measured performance of a broad bandwidth L-band wide flare angle corrugated conical horn and its orthogonal mode transducer are presented. The feed horn is used on prime focus parabolic reflector antennas of a seven-element interferometer, which is part of the Karoo Array Telescope project. The horn was designed to maximize the sensitivity of the radio telescope over a frequency band of 47.6% relative bandwidth. The orthogonal mode transducer design has low insertion and transmission losses and good isolation, and because of its compact size requires a very small cryogenic cooling system.

Led light module

Abstract: An economical LED light module configured to emit a uniform pattern of light from a single LED utilizing a minimal amount of energy and exhibiting a long and useful life is provided The LED light module includes a main hyperbolic reflector and a plug receptacle having an electrical connector configured for electrical communication with a power source A LED is mounted in electrical communication with the electrical connector An elongate light pipe extends between a light receiving end configured to receive light emitted from the LED and a light emitting end The light emitting end has a parabolic reflector positioned concentrically about a focal point of the hyperbolic reflector

Gridded Vivaldi Antenna Feed System for the Northern Cross Radio Telescope

Abstract: The design of a broadband antenna feed system for the cylindrical offset parabolic reflector of the Italian Northern Cross radio telescope is described. Its operative frequency band spans from the Low Frequency Array (LOFAR) upper band, i.e. 120-240 MHz, to the present telescope operative band centered at 408 MHz. The proposed configuration consists of a linear array of gridded Vivaldi (tapered slot) radiators inside a wired subreflector. Numerical simulations have been carried out using both commercial software and a specialized Method-of-Moments approach. They show that the designed feed system provides both a good impedance matching and an efficient illumination of the main reflector in the overall frequency band.

Focusing a TM 01 beam with a slightly tilted parabolic mirror

Abstract: A parabolic mirror illuminated with an incident collimated beam whose axis of propagation does not exactly coincide with the axis of revolution of the mirror shows distortion and strong coma. To understand the behavior of such a focused beam, a detailed description of the electric field in the focal region of a parabolic mirror illuminated with a beam having a nonzero angle of incidence is required. We use the Richards–Wolf vector field equation to investigate the electric energy density distribution of a beam focused with a parabolic mirror. The explicit aberration function of this focused field is provided along with numerically calculated electric energy densities in the focal region for different angles of incidence. The location of the peak intensity, the Strehl ratio and the full-width at half-maximum as a function of the angle of incidence are given and discussed. The results confirm that the focal spot of a strongly focused beam is affected by severe coma, even for very small tilting of the mirror. This analysis provides a clearer understanding of the effect of the angle of incidence on the focusing properties of a parabolic mirror as such a focusing device is of growing interest in microscopy.

Wide-field telescope design for the KMTNet project

Abstract: The Korea Astronomy and Space Science Institute (KASI) are under development three 1.6m optical telescopes for the Korea Micro-lensing Telescope Network (KMTNet) project. These will be installed at three southern observatories in Chile, South Africa, and Australia by middle 2014 to monitor dense star fields like the Galactic bulge and Large Magellanic Cloud. The primary scientific goal of the project is to discover numerous extra-solar planets using the gravitational micro-lensing technique. We have completed the final design of the telescope. The most critical design issue was wide-field optics. The project science requires the Delivered Image Quality (DIQ) of less than 1.0 arcsec FWHM within 1.2 degree radius FOV, under atmospheric seeing of 0.75 arcsec. We chose the prime-focus configuration and realized the DIQ requirement by using a purely parabolic primary mirror and four corrector lenses with all spherical surfaces. We present design results of the wide-field optics, the primary mirror coating and support, and the focus system with three linear actuators on the head ring.

Solar cell based on secondary reflective condensation

Abstract: The invention belongs to the technical field of solar cells and relates to a solar cell based on secondary reflective condensation. The solar cell comprises a parabolic solar condenser, a secondary parabolic reflector, a beam splitter and a photovoltaic cell set, wherein the photovoltaic cell set is composed of photovoltaic cells sensitive to light with different wavelengths; the parabolic solar condenser is opposite to the reflecting surface of the secondary parabolic reflector, the both are coaxial and confocal, and a hole allowing light reflected by the secondary parabolic reflector to pass through is arranged at the bottom of the parabolic solar condenser; the light passing through the hole is divided by the beam splitter into light with different wavelengths, and the light with different wavelengths respectively enters the photovoltaic cells sensitive to corresponding light with different wavelengths in the photovoltaic cell set. The invention further provides another solar cell based on secondary reflective condensation according to the same inventive concept. The solar cell fully displays the advantages of the parabolic secondary reflection, can save material of the photovoltaic cell, and improve the efficiency and product grade.

Imaging device with focused illumination

Abstract: An imaging system comprising a parabolic reflector having a base and defining a first axis, a light source disposed proximate the base essentially along the first axis, an imaging device comprising a zooming lens having a second axis, the imaging device being disposed in front of the light source along the first axis such that the second axis and the first axis are essentially coincident.

Multi-pumping disc solid laser

Abstract: The invention provides a multi-pumping disc solid laser, comprising a semiconductor laser folded array, a pumping light beam collimation system, a cooling finger, a laser disc crystal, a laser output mirror, a parabolic reflector and a first folding mirror and a second folding mirror, wherein the first and the second folding mirrors can perform180-degree reflection; the laser disc crystal is placed at a focal point of the parabolic reflector; the first and the second folding mirrors are arranged on a reflective light path of the parabolic reflector and respectively arranged at two sides of the laser disc crystal; pumping light beams emitted by the semiconductor laser folded array enter into the parabolic reflector, the first folding mirror, the second folding mirror and the laser disc crystal after collimation of a pumping light collimator; and the pumping light beams are subjected to pumping for many times and then a laser resonant cavity acquires and outputs lasers. The disc solid laser can transmit controllable pumping light for many times; the areas of pumping spots are reasonable; the power-density distribution is even; and only the simple collimation is required to be carried out on incident pumping light beams so as to output the lasers with high power, high efficiency and high beam quality.

Optimized Bands: A New Design Concept for Concentrating Solar Parabolic Mirrors

Abstract: Parabolic concentrator mirrors are an important component of many solar energy systems, particularly solar mirror collectors. Precision parabolic mirrors are expensive to fabricate and to transport. Here, a new concept for designing and fabricating precision parabolic mirrors is presented. The mirror is formed from a thin flat very flexible metal sheet with a highly reflective surface. Attached to the rear surface of the mirror sheet is a backbone band whose figure is optimized to form the reflective sheet into a precision parabola when its two ends are pulled toward each other. An analytical model to optimize the shape and thickness of the band is presented. The validity of the concept is demonstrated using Finite Element Analysis (FEA) and laboratory experiments. The concept would permit flat mirror elements to be easily fabricated and efficiently packaged and shipped to field sites and assembled into the parabolic trough concentrators with potentially substantial costs reductions compared with the conventional methods.

Device for testing focal spots focused by solar parabolic concentrator

Abstract: The invention relates to a device for testing focal spots focused by a solar parabolic concentrator. The device takes full advantage of the linear beams generated by a semiconductor laser and tests the focused focal spots through reflection of a parabolic mirror. The device is simple and the method is feasible and is widely applied to various parabolic concentrators. The device belongs to the technical field of solar energy utilization.

Quasi-parabolic solar concentrator and method

Abstract: A quasi-parabolic reflector and method are provided for a solar concentrator which produces a unique radiation pattern which is less susceptible to surface defects, less sensitive to target distance irregularities, and having greater uniformity of intensity for PV applications in comparison to that produced by true parabolic reflectors. Cross-sections of the quasi-parabolic reflector include spaced reflective surfaces which have focal areas spaced one from the other about an axis of symmetry. A method for forming petals of a quasi-parabolic reflector includes stamping them into shape using a stamping apparatus with a higher radius of curvature than the finished petal and iteratively testing and stamping the petal until the petal passes or fails a quality and accuracy threshold.

A Novel Approach for Designing Parabolic Mirrors Using Optimized Compliant Bands

Abstract: Parabolic concentrator mirrors are an important component of many solar energy systems, particularly solar mirror collectors. Precision parabolic mirrors are expensive to fabricate and to transport. Here, a new concept for designing and fabricating precision parabolic mirrors is presented. The mirror is formed from a thin flat very flexible metal sheet with a highly reflective surface. Attached to the rear surface of the mirror sheet is a backbone band whose figure is optimized to form the reflective sheet into a precision parabola when its two ends are pulled toward each other. An analytical model to optimize the shape of the band is presented. The validity of the concept is demonstrated using Finite Element Analysis and laboratory experiments. The concept would permit flat mirror elements to be easily fabricated and efficiently packaged and shipped to field sites and assembled into the parabolic trough concentrators with potentially substantial costs reductions compared with conventional methods.Copyright © 2011 by ASME

Optical device for wide waveband plane grating dispersion type imaging spectrometer

Abstract: The invention provides an optical device for a wide waveband plane grating dispersion type imaging spectrometer, and relates to the technical field of imaging spectrometers in the earth observation field. The optical device solves the defects of the conventional plane grating spectrometer that only the aberration of center wavelength is corrected, the residual aberration is larger, and large astigmatism exists along the length direction of a slit. The optical device consists of an aperture diaphragm, an off-axis parabolic mirror, an entrance slit, a spherical collimating mirror, a plane grating, a plane mirror, a toroidal focusing mirror and a planar array focal plane detector. The entrance slit is positioned on a focal plane of a front optical system; the front optical system consists of the aperture diaphragm and the off-axis parabolic mirror; the emergent light passing though the entrance slit is projected onto the spherical collimating mirror and is then projected onto the plane grating after being collimated by the spherical collimating mirror; and the diffraction light emerged from the plane grating is projected onto the toroidal focusing mirror after being reflected by the plane mirror and then is focused and imaged by the toroidal focusing mirror onto the planar array focal plane detector. The optical device is particularly suitable for a hyperspectral imaging system in the aerospace remote sensing earth observation field.

Parabolic reflector antenna

Abstract: The antenna consists of at least one parabolic reflector with a circular edge. At least one screen with a width less than half of the length of the circular edge is arranged on the circular edge on the inside of the perimeter of the parabolic reflector. Preferably, the screen is made of at least two flat sections linked together, two contiguous sections forming a concave angle α that is between 90 degrees and 150 degrees.

Direct insertion type smoke ultraviolet differential probe with on-line calibration optical path

Abstract: The invention relates to a direct insertion type smoke ultraviolet differential probe with an online calibration light path, which belongs to a smoke monitoring device. A control cabinet is provided with a probe; the front end of the probe is provided with a measuring port; the probe is connected with a spectrograph through an optical fiber; a deuterium light source emits ultraviolet visible light beams; the ultraviolet visible light beams are projected to a fan-shaped parabolic mirror, enter into the probe and are transmitted to the spectrograph through the optical fiber, thus, the smoke monitoring is realized; a reflector reflects the light beams which are reflected by the fan-shaped parabolic mirror into a gas pool; standard gas is introduced into the gas pool; and the light beams are absorbed by the standard gas; transmission light is coupled into the spectrograph through the optical fiber to calibrate the light intensity, thus, the online calibration is realized. The direct insertion type smoke ultraviolet difference probe provided by the invention can switch the measurement and calibration states; after the light beams are reflected at the fan-shaped parabolic mirror, the emitting direction of the light beams is controlled by the reflector; and the online calibration is realized under the condition that the probe is not extracted from a smoke flue.

Lighting and/or signalling device for an automobile comprising a surface light source

Abstract: The device (1) has a reflector (2) e.g. parabolic reflector i.e. parabolic mirror, a main light source (5) and an auxiliary light source (3) i.e. surface light source e.g. daytime light, arranged such that light rays (7) emitted by a main light source pass through the auxiliary light source after reflection on the reflector. The surface light source includes organic LED. A housing (101) is closed by a closing glass (102), and the main and auxiliary light sources are provided inside the housing. The auxiliary light source is interposed between the glass and the main light source.

Solar powered compressor/pump combination

Abstract: A solar powered compressor and pump is disclosed having a trough-shaped parabolic reflector for heating a conduit of refrigerant as it passes through the system. The compressor/pump combination includes a lens that covers the reflector and insulates and protects the reflector from the elements while increasing the intensity of the sun's energy entering the reflector. The reflector converts the sun's energy into heat that superheats the refrigerant as it passes through the reflector, reducing or eliminating the amount of mechanical work that the system has to do to achieve the needed superheating stage.

Parabolic reflector and relative led lighting device

Abstract: Axial symmetric parabolic reflector comprising an opening and which is positionable in a position in which it surround the at least a led lighting source for reflect and distribute in homogeneous way a light flux toward the opening. The axial symmetric parabolic reflector comprises a mask which is made integral with the same, besides the mask being positionable in proximity of the at least a led lighting source in a way to results substantially orthogonal to a longitudinal direction in order to avoid the direct eyesight of the at least a led lighting source through the opening. The mask further comprises a reflecting surface which includes a reflecting axial symmetric groove having a section substantially shaped as a “3”, and besides at least a filter or a lens in order to avoid the glare by indirect light of the at least a led lighting source.

Multi-optical path sheet type laser amplifier

Abstract: The invention discloses a multi-optical path sheet type laser amplifier, comprising a pump light optical path system and a laser optical path system The optical path of the laser amplifier is that: a pump beam is emitted from a pump light source, penetrates through an optical coupling system and a dichroic beam splitter and intersects with a laser beam directly reflected by an input mirror on the surface of the bichroic beam splitter, so as to form a coincident light beam of the pump light and laser, the coincident light beam is incident to a parabolic reflector, is subject to refraction and reflection among the parabolic reflector, a laser gain medium sheet and a birectangular reflecting prism group, and finally is output parallel to the direction of the incident light, and the beam is incident to an output mirror and is reflected and then output The multi-optical path laser amplifier structure disclosed by the invention combines the pump light optical path and the laser optical path into one and realizes multi-optical path amplification, thus improving utilization ratio of the pump light, improving effective gain in the amplifying process and being applicable to lasers used for scientific research and industrial processing

Method and device for two-stage solar concentration and spectrum splitting based on dish concentration

Abstract: The present invention discloses a method and device for two-stage solar concentration and a spectrum splitting dish reflector based on dish concentration. A parabolic dish reflector is provided with a central light hole. A CPV panel and a solar-to-heat receiver are positioned at the two sides of the axial line of dish reflector, respectively, under the light hole. A splitting lens is placed at a certain distance from the apex of dish reflector over the light hole. The splitting film is applied to the curved surface of the lens near the parabolic dish, as a spectrum splitting surface. The curved surface of the lens far from the parabolic dish is covered by silver, as a reflecting surface. A supporting structure is provided between the dish reflector and the splitting lens. The whole system with a dual-axis tracking system is placed on the foundation of a support. The present invention can simultaneously realize solar energy concentration and spectrum splitting, to obtain two concentrated spots of different spectrums under the system, which can effectively reduce energy consumption of tracking system and improve system balance and wind resistance. The present invention can adjust the concentration ratio of two beams individually to satisfy the optimal concentrating intensity needed by the CPV panel and the solar-to-heat receiver.

Two-stage asymmetrical composite parabolic reflector condenser in smooth transition connection

Abstract: The invention relates to a two-stage asymmetrical composite parabolic reflector condenser in smooth transition connection, which comprises an upper-stage parabolic reflector and a lower-stage parabolic reflector, wherein the lower-stage parabolic reflector comprises axial symmetrical parabolic reflectors; the upper-stage parabolic reflector comprises asymmetrical parabolic reflectors; the profile parabola principal axes of the upper-stage parabolic reflector and the lower-stage parabolic reflector are positioned in the same axis position; the absorption end width of the upper-stage parabolic reflector and the open end width of the lower-stage parabolic reflector are equal; the upper-stage parabolic reflector and the lower-stage parabolic reflector adopt the smooth connection processing; the upper-stage parabolic reflector comprises parabolas at the left and right sides; and the received half-angle sine value ratio of the parabolas at the left and right sides is equal to the solar radiation intensity ratio of the region in spring and winter The two-stage asymmetrical composite parabolic reflector condenser provided by the invention can effectively reduce the optical radiation energy loss, widely receive solar rays and has good season adaptability

Portable detection device for detecting sighting line zero position of infrared sniperscope

Abstract: The invention discloses a portable detection device for detecting a sighting line zero position of an infrared sniperscope, and belongs to the technical field of infrared optics detection. The conventional detection device is not a shaped special instrument. The detection device provided by the invention is characterized in that: a sealed hood is fastened on a base; a black body, a round disc target, a planar reflector and an off-axis parabolic mirror are fixed on the base and positioned in the sealed hood; a buckling base is fixed on the base and positioned out of the sealed hood. An infrared window is formed on the lateral wall of the sealed hood and opposite to the buckling base; a cross slot hole and a plurality of different round holes are formed on the round disc target; and the centre of the cross slot hole and the centers of a plurality of round holes are positioned on the same circle of the round disc target. The off-axis parabolic mirror, the infrared window and the buckling base are sequentially arranged by taking the axis of parallel light reflected by a reflector on the off-axis parabolic mirror as an axis. The black body, the centre of the cross slot hole or the center of one of the plurality of round holes and the planar reflector are coaxially arranged on one side of the axis of the reflector on the off-axis parabolic mirror as an axis sequentially.