616 results about "Reflection loss" patented technology

The invention provides a Ku/Ka frequency band circularly polarization integrated receiving and transmitting feed source antenna applied to antenna systems, such as a paraboloid antenna and the like, in satellite communication. The antenna adopts a coaxial nested compact structure, and is applied to Ku frequency band and Ka frequency band at the same time. The basic structure of a feed source comprises a circular waveguide, on which a pointed cone shaped dielectric rod is loaded, a flange, a coaxial waveguide, a symmetrical SMA connector pair, a circular polarizer and an orthogonal mode coupler, wherein the feed source in the Ka frequency band is applied to dual circular polarization, has rotary symmetrical radiation directional diagrams, the circularly polarization axial ratio in Ka double band is smaller than minus 2dB, and the transmitter-receiver isolation is smaller than minus 70dB; and the feed source in the Ku frequency band is applied to dual circular polarization, has rotary symmetrical radiation directional diagrams, a cross polarization level smaller than minus 40dB, and good transmitter-receiver isolation and reflection loss.

A catadioptric projection optical system for forming a reduced image of a first surface (R) on a second surface (W) is a relatively compact projection optical system having excellent imaging performance as well corrected for various aberrations, such as chromatic aberration and curvature of field, and being capable of securing a large effective image-side numerical aperture while suitably suppressing reflection loss on optical surfaces. The projection optical system comprises at least two reflecting mirrors (CM1, CM2), and a boundary lens (Lb) whose surface on the first surface side has a positive refracting power, and an optical path between the boundary lens and the second surface is filled with a medium (Lm) having a refractive index larger than 1.1. Every transmitting member and every reflecting member with a refracting power forming the projection optical system are arranged along a single optical axis (AX) and the projection optical system has an effective imaging area of a predetermined shape not including the optical axis.

A vertical electrode structure of GaN-based light emitting diode discloses an oxide window layer constructing the GaN-based light emitting diode of vertical electrode structure, which effectively decreases the Fresnel reflection loss and total reflection, and further advances the luminous efficiency. Moreover, the further included metal reflecting layer causes the reflection without the selective angle of incidence, thus increasing the coverage of the reflecting angles and further reflecting the light emitted from a light emitting layer effectively. In addition, the invented structure can also advance the function of heat elimination and the electrostatic discharge (ESD) so as to the increase the operating life of the component and to be applicable to the using under the high current driving. Moreover, the vertical electrode structure of the present invention is able to lower down the manufacturing square of the chip and facilitate the post stage of the conventional wire bonding process.

Provided is a solar heat collector based on a groove type parabolic mirror and an artificial blackbody. Three vacuum heat collecting tubes are arranged in a cavity to reduce reflection loss caused by perpendicular incidence of sunlight and improve the sunlight absorption rate. By utilizing condensation of double-reflecting mirror with groove type paraboloid and ellipsoid, the reflected light can be well focused on the heat collecting tubes, and the coupling degree of the groove type solar heat collector to the sunlight is simultaneously improved. The vacuum heat collecting tubes are installed on the lower portion of a condensation device so that a condensation plate can conveniently trace the sun. In addition, the solar heat collector further has the remarkable advantages that installation is convenient, impact influences of the outside world on a glass tube are small, and liquid leakage caused by rotation of the heat collecting tubes is overcome simultaneously.

Illumination lenses (1806, 1902, 2002, 2100, 2200, 2300, 2400, 2500, 2600, 2700, 2800, 3006, 3100) having surfaces shaped according to given differential equations in order to distribute light in a highly controlled manner with minimum reflection losses are provided. Both primary lenses and secondary lenses are provided. The secondary lenses include outer surfaces that are defined as loci of constant optical distance from an origin at which a light source is located. Versions are provided of both the primary and secondary lenses having Total Internal Reflection (TIR) wings. These are useful in the case that narrower distributions of light are required. A method of refining the shape of the lenses to obtain more obtain lenses that produce better fidelity ideal light distributions is also provided.

A low-cost, compact circular waveguide array antenna which improves an antenna reflection loss characteristic and enables an improvement in radiation characteristics, particularly radiation gain. The circular waveguide array antenna includes feeding portions which feed electromagnetic waves to one ends of circular waveguides and radiation apertures which radiate the electromagnetic waves at the opposite ends. Each circular waveguide includes a conical horn, with a diameter of a feeding side aperture at the feeding portion end being a, a diameter of the radiation aperture being d, which is larger than the diameter a of the feeding side aperture, and an opening angle being 2α. If a wavelength of a central frequency of an employed frequency band is λ, then a value of α, which is half of the opening angle 2α, is set between 0.8×Arcsin(0.1349114/(d/λ)) and 1.2×Arcsin(0.1349114/(d/λ)).

The invention discloses an electromagnetic shielding composite material. Electromagnetic wave absorption layers and electromagnetic wave reflection layers are alternately overlapped to form electromagnetic shielding function bodies; the electromagnetic wave absorption layers are formed by compositing matrix resin, fiber carriers and electromagnetic absorption function bodies; the electromagnetic wave absorption layers are formed by compositing matrix resin and electromagnetic gradient reflection function bodies; in the overlapped electromagnetic wave reflection layers, the mass percentage compositions of short cut carbon fibers increase in gradient along the incident directions of the electromagnetic waves. According to the electromagnetic shielding composite material of the invention, the incident electromagnetic waves generate multi-reflection; the propagation paths of the electromagnetic waves in the material are increased; increase of the multi-reflection loss and absorption loss enables the shielding efficiency of the material to be increased; in adoption of the reflection layers of gradient structure, the electromagnetic waves will not escape away from the shielding material rapidly for reflection; more electromagnetic waves can enter the next shielding unit; therefore, the shielding efficiency of the material is further improved.

The invention discloses a laser broadband cladding device and method. The device mainly consists a beam splitter prism and two converging lenses, wherein the beam splitter prism is formed into a molded surface by two beam splitter planes which are symmetrically arranged and are intersected at a certain angle; an incident solid laser beam can be symmetrically reflected by the two beam splitter planes to form two reverse emergent laser beams; the two converging lenses are respectively opposite to the two beam splitter surfaces of the beam splitter prism; two beams of laser reflected by the beam splitter prism can be respectively reflected into parallel near rectangular laser beams by the converging lenses; the distance between the two beams of parallel near rectangular light is shorter and shorter in the focusing process to form long and narrow focusing light spots; and the light spots are overlapped on a focal plane. The laser broadband cladding device disclosed by the invention has the advantages of big cladding width and high efficiency, a powder bundle does not interfere with a light beam too early in the falling process, and the light beam has a small reflection loss; the powder enters the light in an accurate, straight, thin and stiff way, is evenly distributed and has the advantages of small diffusance and high use ratio; the coupling precision of the powder and the laser beam is high; turnaround scanning forming can be realized; a cladding channel has even tissue; the overlapping joint quality is good.

Compact optical frequency sources are described. The comb source may include an intra-cavity optical element having a multi-material integrated structure with an electrically controllable active region. The active region may comprise a thin film. By way of example, the thin film and an insulating dielectric material disposed between two electrodes can provide for rapid loss modulation. In some embodiments the thin film may comprise graphene. In various embodiments of a frequency comb laser, rapid modulation of the CEO frequency can be implemented via electric modulation of the transmission or reflection loss of an additional optical element, which can be the saturable absorber itself. In another embodiment, the thin film can also be used as a saturable absorber in order to facilitate passive modelocking. In some implementations the optical element may be formed on a cleaved or polished end of an optical fiber.

A laser having an optical parametric oscillator for providing a preselected wavelength beam is provided. A nonlinear crystal cut for phase matching condition preferably cut for noncritical phase matching conditions for the fundamental beam wavelength and the preselected wavelength beam is located in both the optical parametric oscillator cavity and laser resonator cavity.

The optical axis of the laser resonator and the optical axis of the optical parametric oscillator cavity are at least partially separate and partially overlap. The laser crystal is located in the laser resonator cavity but not in the optical parametric oscillator cavity. Each end of the OPO nonlinear crystal that intersects the optical axes has a Brewster cut for both the fundamental and preselected wavelength beams so that the fundamental and preselected wavelength beams incident on the nonlinear crystal at approximately the Brewster angle and pass through without substantial reflection loss.

The fundamental wavelength beam is directed into the optical parametric oscillator cavity and incidents on nonlinear crystal having a Brewster cut at each end for fundamental and preselected wavelength beam without substantial reflection loss. A portion of the fundamental wavelength beam is partially converted to a preselected wavelength beam. The fundamental beam and the preselected wavelength beams are reflected back through the nonlinear crystal. Preselected wavelength beam is separated from the fundamental wavelength beam.

The invention relates to a high-temperature wave-absorbing composite material and a preparation method thereof and provides a SiC@SiO2@ferrite high-temperature wave-absorbing composite material and apreparation method thereof. The objective of the invention is to overcome the technical problems of complex preparation technologies, narrow wave-absorbing ranges and no shielding effect of conventional wave-absorbing material preparation methods. The wave-absorbing composite material uses SiC as a core; a SiO2 layer coats the core; and ferrite particles are adhered onto the SiO2 layer. The preparation method comprises the following steps: 1, pretreating the surface of silicon carbide; 2, synthesizing silica-coated silicon carbide SiC@SiO2; 3, after sensitization and activation of SiC@SiO2, reacting the SiC@SiO2 with a salt for preparing ferrite and a strong reducing agent in alkaline liquor, then carrying out calcination so as to obtain the SiC@SiO2@ferrite high-temperature wave-absorbingcomposite material. The material of the invention has a reflection loss of less than -5dB in a 8-to-12-GHz band and a Ku band and a maximum reflection loss of -14 dB, and can be used in the field ofwave-absorbing materials.

The invention relates to an organic electroluminescent technology and discloses a method for improving the luminous efficiency. The method can be applied to various types of OLED (Organic Light Emitting Diode) devices of bottom emission, top emission, transparency and the like. The invention provides an optical transition layer material, an optical substrate (packaging layer), an OLED, and manufacturing methods thereof. If the OLED is the bottom-emission OLED, an optical transition layer is manufactured on the substrate; if the OLED is the top-emission OLED, the optical transition layer is manufactured on the packaging layer; and if the OLED is the transparent OLED, the optical transition layer can be independently or simultaneously manufactured on the substrate or the packaging layer. An organic material main body with high light transmittance and moderate refractive index and an inorganic nano grain with the high light transmittance and low absorption rate are selected; the inorganic nano grain is used as a scattering medium to be scattered into the organic material main body to prepare the optical transition layer material; and the optical transition layer material is used for preparing an optical transition layer on the substrate (packaging layer) including glass and the like, so that the full-reflection loss of emergent light is effectively reduced and the luminous efficiency of the OLED is improved by 20-50%.

The invention relates to a low-illumination image enhancement method based on Retinex and deep learning. An existing low-illumination data set is analyzed, low-illumination image RAW data and RGB dataare collected at the same time through multiple cameras and multiple shooting means, and the image diversity of the data set in a real scene is improved. An end-to-end improved convolutional self-encoding network structure is provided, is composed of an encoder and a decoder, and comprises an image decomposition module, an illumination adjustment module and an image reconstruction module. The image decomposition module encodes the image to obtain a reflection feature code and an illuminance hidden code. The illuminance adjusting module automatically adjusts the illuminance of the image, and the image reconstruction module recovers and reconstructs the image content. Joint loss function constraint network training, namely reconstruction loss, color loss and reflection loss, is designed. According to the method, the problems of noise removal, color distortion, image detail recovery and the like of the enhanced image in a low-light environment are solved, and the effectiveness and advancement are verified through experiments.

The invention provides a preparation method of a single crystal silicon texture surface structure, relates to the technical field of solar energy application, and is invented to effectively reduce reflection loss of incident light of a texture surface and to increase forming speed of a texture surface. The preparation method of a single crystal silicon texture surface comprises the following steps: depositing discrete metal particles on a silicon wafer surface; performing corrosion of the silicon wafer deposited with metal particles by a mixed solution of hydrofluoric acid and hydrogen peroxide so as to form a texture surface structure on the silicon wafer surface. The invention is applicable to the preparation process of solar cells.

An microscope objective lens system comprises a first lens unit including a plurality of cemented lens components and converging light coming from an object, a second lens unit including a negative lens component having a strong concave surface on the image side, and a third lens unit including a cemented doublet composed of a negative lens element having a concave surface on the object side and a positive lens element, wherein the objective lens system satisfies the following conditions:1.65<=nd<=1.825<=nud<=41T360>=0.5wherein nd and nud are refractive index at the Fraunhofer d-line and the Abbe's number of the positive lens element in the third lens unit, respectively, and T360 is an internal transmittance except for a reflection loss at 360 nm for 10 mm thickness of material forming the positive lens element in the third lens unit.

The present invention provides a technique of reducing an incident/outgoing loss of a photonic crystal. On each of incident/outgoing sides of a photonic crystal, an antireflection layer made of a photonic crystal is disposed. At the incident side of a photonic crystal 200 having an effective refractive index n₂, a photonic crystal 100 having an effective refractive index n₁ satisfying the relation of n₁<n₂ is disposed, and the thickness of the photonic crystal 100 is controlled so that reflection components from interfaces 210 and 110 cancel each other out by interference, thereby reducing a total reflection loss on the incident side. The outgoing side is similarly constructed.

There is provided a projection apparatus using an oblique projection optical system, which generates little reflection loss by providing a linear Fresnel lens at an incident surface in the case where the apparatus is used as a linear system, wherein said linear Fresnel lens makes total reflection of image light, and is capable of obtaining total surface property with good brightness in a region with small incident angle onto a screen, by using a total reflection Fresnel lens and a refraction Fresnel lens in combination. In addition, total surface property with further good brightness can be obtained by using a plurality of projection image display apparatuses in the same projection apparatus.

Disclosed are an apparatus and a method for preventing the degradation of RF performance due to a change in impedance of an antenna in a mobile communication terminal. The mobile communication terminal includes a plurality of impedance matching circuits and a controller of the mobile communication terminal is adapted to measure the reflection voltage of the antenna, select one impedance matching circuit corresponding to the measured reflection voltage, and connected with the antenna through the selected impedance matching circuit As a result, when the impedance value of the antenna is changed, it is possible to prevent the degradation of performance of the RF module of the mobile communication terminal by using an impedance matching circuit, which can optimize the reflection loss caused by the reflection voltage of the antenna according to a change in impedance value.