65 results about "Scattering loss" patented technology

The present application relates to the technical field of optical functional film, disclose a kind of high haze calcite BOPET composite diffusion film and its preparation method and application, by adopting gradient micropore-dense layer composite structure design, and optimizing each layer function composition, on the one hand in surface dense layer, utilize low filling nano calcite to build high dense structure, effectively reduce surface light reflection, improve mechanical strength, while avoiding light transmittance loss;On the other hand in bottom microporous layer, introduce double-particle-size calcite particle nanoparticles and microparticles, build multiscale scattering network, realize the efficient light diffusion of wide spectral range 380-780 nm, significantly reduce interface scattering loss, substantially improve the light transmittance and haze balance of optical film;Meanwhile, through the integration of co-extrusion-biaxial stretching process, optimize inorganic / organic interface combination, effectively solve the problem of filler agglomeration, while reducing the preparation cost.

The invention discloses a grating waveguide structure of an optical communication device and a preparation method thereof, and the method comprises the steps: forming a plurality of metal masks on a silicon carbide substrate, employing an atomic layer deposition technology, forming metal oxide layers on the top surfaces and side surfaces of the metal masks, carrying out the layer-by-layer in-situ filling and flattening of surface roughness defects of the metal masks, and carrying out the in-situ filling and flattening of the surface roughness defects of the metal masks. The metal oxide layer is etched back to form a side wall structure with a smooth surface, the exposed surface of the silicon carbide substrate is etched to form a plurality of grooves which are periodically arranged and have smooth side walls, the side wall structure and the metal mask are removed after the side walls of the grooves are protected by adopting an organic matter layer, and the silicon carbide substrate is obtained. After the organic matter layer is removed and the side wall is subjected to first pretreatment, a first waveguide cladding layer, a first waveguide layer, a second waveguide layer and a second waveguide cladding layer are sequentially deposited on the inner wall of the groove and the surface of the silicon carbide substrate. The device precision can be improved, the scattering loss is obviously reduced, and the energy attenuation of optical signals is reduced.

The invention discloses a partitioned scattering optical lens for myopia control and a design method of the partitioned scattering optical lens, which are applied to the technical field of optics, and aims to solve the problem that the central visual quality and the peripheral myopia control effect cannot be considered at the same time in the prior art, the optical lens comprises a central optical region, a peripheral optical region and a smooth transition zone, the central optical area is low in scattering coefficient and high in MTF, a high modulation transfer function and low scattering loss are achieved, the peripheral optical area is high in scattering coefficient and low in MTF, the central optical area is used for inducing peripheral myopic defocus, the smooth transition area is used for achieving continuous gradual change of the scattering coefficient, visual sudden change is avoided, and visual comfort is ensured. The design method comprises the steps of eye parameter acquisition, optical performance target definition, microstructure design and simulation optimization, through the scheme, effective decoupling of central vision and peripheral myopia control is achieved, high-definition vision is ensured, myopia progress is restrained, and wearing comfort is improved.

A method and apparatus for inscribing a high-temperature stable Bragg grating in an optical waveguide, comprising the steps of: providing the optical waveguide; providing electromagnetic radiation from an ultrashort pulse duration laser, wherein the wavelength of the electromagnetic radiation has a characteristic wavelength in the wavelength range from 150 nanometers (nm) to 2.0 micrometers (μm); providing cylindrical focusing optics; providing a diffractive optical element that when exposed to the focused ultrashort laser pulse, creates an interference pattern on the optical waveguide, wherein the irradiation step comprises irradiating a surface of the diffractive optical element with the focused electromagnetic radiation, the electromagnetic radiation incident on the optical waveguide, from the diffractive optical element, being sufficiently intensive to cause permanent (Type II) change in the index of refraction within multiple Bragg grating planes in the core of the optical waveguide resulting from at least one micropore.

The invention relates to the technical field of ultrasonic import, and discloses an ultrasonic import method and an ultrasonic import device.The ultrasonic import method comprises the steps that firstly, focusing parameters are matched from a pre-built parameter library based on mode information, multiple import scenes are achieved through modeling parameter adaptation, the application range of the device is expanded, and diversified use requirements are met; constructing a three-dimensional focusing coordinate system by taking the center of the array element matrix as an original point, and ensuring that coordinate calculation fits an actual transdermal scene; then, delay time is determined by calculating coordinates of each array element and an acoustic beam path of a focus point, in-phase superposition of ultrasonic waves at the focus point is ensured, phased array focusing is achieved, scattering loss of acoustic energy in the propagation process is reduced, and the acoustic energy transmission efficiency of a unit area is improved; in the application, through accurate positioning of the coordinate system, quantification of the acoustic beam path and dynamic adjustment of the delay time, the focusing precision is remarkably improved, it is ensured that the ultrasonic energy is accurately converged in the targeted introduction area, and the problem that targeted introduction is difficult to realize by a traditional method is effectively solved.

The utility model relates to a water-blocking film structure. The structure integrates a water-blocking layer, an anti-dazzle base material layer and an optical adhesive layer. A prism structure composed of prisms arranged in parallel in an array is designed in the anti-dazzle base material layer, the vertex angles of the prisms face the waterproof layer, and the prisms are tightly bonded through the optical adhesive layer. And the depth of the vertex angle of the prism embedded into the optical adhesive layer is accurately controlled to be less than 50% of the height of the prism, so that the water-blocking film is ensured to maintain good waterproof performance without sacrificing the light transmission and definition. The optical adhesive layer not only covers the plane part of the anti-dazzle base material layer, but also is tightly attached to the prism structure, so that light refraction and scattering loss is reduced. The utility model also provides an electronic paper display module comprising a TFT driving unit, an electronic paper film and the water-blocking film, and through the improvement of the structure of the water-blocking film, the module can have high stability and excellent environmental adaptability and long-term reliability on the basis of low power consumption and high readability.

According to the gallium nitride-based semiconductor laser with the gradually-changed polarized optical phonon energy waveguide layer, a fitting curve of In ion strength distribution or In atom concentration distribution of an upper waveguide layer and a lower waveguide layer is tested through SIMS, and a fitting curve of polarized optical phonon energy distribution meets any function distribution of Log3P1, Lop2P2 and Biphase. The spatial continuous regulation and control of the phonon energy of the optical field are realized, so that the LO phonon energy is continuously and gradually changed along the propagation direction, the phonon energy gradient is formed, the LO phonon scattering is improved, the inelastic scattering and energy relaxation of carriers and LO phonons are inhibited, the carrier transportation and phonon scattering are optimized, the service life of the carriers and the gain retention time are prolonged, and the optical field performance is improved. According to the invention, the threshold current density is reduced, the thermal stability of the laser is improved, the use power and the use temperature of the laser are improved, meanwhile, the phonon energy valley value is matched with the quantum well gain peak, the scattering loss is inhibited, additional scattering caused by phonon energy mutation is avoided, the light field limitation is enhanced, and the slope efficiency is improved.

A novel optical cable connector box provided by the utility model comprises a box body and an optical fiber disc installed in the box body, the optical fiber disc comprises a unit disc body and an end cover, the unit disc body is of a top opening structure, the two end portions of the unit disc body are provided with inlets and outlets for optical cables to go in and out, and the outer wall of the unit disc body is provided with a plurality of positioning blocks; according to the optical cable wiring requirement, the corresponding number of unit disc bodies are stacked and combined, combined installation of multiple layers of unit disc bodies is achieved, each layer of unit disc body can independently coil optical fibers, and the situation that the optical fibers are prone to being crossed and overlapped due to insufficient space in the coiling process can be effectively avoided; the runway-shaped optical fiber coiling space is formed in the unit disc body, torsion and extrusion of an optical cable in the fiber coiling process are reduced through the runway-shaped optical fiber coiling space, the stress level of the optical fiber is reduced, scattering loss caused by excessive bending of the optical cable can be avoided, signal attenuation is reduced, and stable transmission of optical signals is ensured.

The invention provides a resonator and a photon chip, and the resonator comprises a micro-ring waveguide and a straight waveguide, the coupling region of the straight waveguide and the micro-ring waveguide is a coupling section, the straight waveguide and the micro-ring waveguide have the same waveguide structure at the coupling section, and the waveguide structure comprises a first waveguide arm and a second waveguide arm, a radiation groove is formed between the first waveguide arm and the second waveguide arm; a plurality of first grating grooves arranged along the extension direction of the radiation groove are formed in one side, facing the radiation groove, of the first waveguide arm; a plurality of second grating grooves arranged along the extension direction of the radiation groove are formed in one side, facing the radiation groove, of the second waveguide arm; and the first grating grooves are aligned with the second grating grooves one by one. The second waveguide arm and the first waveguide arm in the waveguide structure of the coupling section can form a sub-wavelength grating groove-shaped waveguide with a continuous outer boundary. Due to the fact that the outer boundary is continuous, mode disturbance and side wall scattering can be effectively restrained, and scattering loss of the resonator can be remarkably reduced.

The application discloses a grating waveguide structure of an optical communication device and a preparation method thereof. The method comprises the following steps: forming a plurality of metal masks on a silicon carbide substrate; forming a metal oxide layer on the top surface and the side surface of the metal mask by adopting an atomic layer deposition process; layer by layer in-situ filling and smoothing the surface roughness defects existing in the metal mask; back-etching the metal oxide layer to form a side wall structure with a smooth surface; etching the surface of the exposed silicon carbide substrate to form a plurality of periodically arranged grooves with smooth side walls; removing the side wall structure and the metal mask after protecting the groove side wall by adopting an organic layer; removing the organic layer and performing a first pretreatment on the side wall; and sequentially depositing a first waveguide cladding layer, a first waveguide layer, a second waveguide layer and a second waveguide cladding layer on the inner wall of the groove and the surface of the silicon carbide substrate. The application can improve the device precision, significantly reduce the scattering loss and reduce the energy attenuation of the optical signal.

A thin film lithium niobate waveguide scattering and absorption loss spectrum separation detection method comprises the following steps: acquiring transmission loss of a thin film lithium niobate waveguide under different wavelengths and an energy distribution ratio of each wavelength guided mode in different media so as to determine a total transmission loss and a mode field space energy ratio; and constructing a space energy attribution model based on the total transmission loss and the mode field space energy ratio. In the space energy attribution model, an interface coupling loss item is introduced, and a loss dominant interval is established according to the interface coupling loss item. And extracting a loss spectrum in the loss dominant interval, and carrying out consistency verification on the loss spectrum by taking a mode field space energy proportion as a weight so as to output a scattering loss spectrum and an absorption loss spectrum. Under the condition of a high leakage field, even if surface absorption and scattering coupling loss caused by cladding surface pollution, moisture adsorption and interface defects does not meet the linear superposition relation any more, the accuracy of waveguide detection can be guaranteed.

A system for measuring roughness of a core sidewall of an optical waveguide based on mode excitation is provided, in which an optical waveguide to be measured is arranged between a few-mode long-period fiber grating and an optical power meter; the laser beam is incident on the optical waveguide to be measured after passing through the few-mode long-period fiber grating, and then is incident on the optical power meter after being subjected to a scattering loss caused by the roughness of the core sidewall of the optical waveguide to be measured; and the processor is configured to calculate an equivalent value of the roughness of the core sidewall according to the output power detected by the optical power meter, the output modes of the few-mode long-period fiber grating and the mode of the optical waveguide to be measured.

The invention discloses a GaN bridging micro-disk laser capable of directionally emitting laser and a preparation method thereof, and belongs to the technical field of semiconductor photoelectric devices. A bridging polygonal microcavity structure is provided, extending bridge structures are introduced at vertex angles of a quadrilateral microcavity and a circular microcavity, mirror symmetry of polygons is broken through geometric coupling of bridges and a main cavity, and an echo wall mode is directionally coupled to an output waveguide. The bridging structure can be achieved through conventional photoetching and dry etching, complex deformation etching is not needed, and the technology is compatible with an existing CMOS production line. The side wall damage is repaired through wet etching, the light field scattering loss is reduced, the mode stability is improved, and a robust solution is provided for high-density integration.

The utility model relates to cell imaging device, including box, the base for placing cell plate tray is set up in the box, the top fixed mounting of box has two support plates, and is provided with the shooting mouth between two support plates, and the shooting mouth is located the just above of base, the sliding frame of sliding connection on support plate, fixed mounting has the photographing assembly for shooting on sliding frame, photographing assembly is located the just above of base and is coaxial with the shooting mouth, and the shooting mouth is located the just above of base, and photographing assembly is vertically aligned cell plate tray through the shooting mouth, makes the shooting light path present straight line, can reduce the refraction, scattering loss in the propagation process of light, avoids the imaging blur caused by weak fluorescent signal.

This invention discloses a heterogeneous integrated electro-optic modulator and its alignment method based on write field splicing compensation, relating to the field of silicon-based optoelectronics technology. The modulator comprises, from bottom to top, a silicon substrate with a thermal oxide layer, a bottom patterned waveguide layer, an intermediate transition dielectric layer, a top electro-optic thin film layer, and a top traveling-wave electrode structure. The bottom waveguide layer has a write field splicing region along the light propagation direction, within which a thermal compensation structure is configured, and a dedicated alignment mark is provided within a designated area. This mark is formed synchronously with the waveguide layer and the compensation structure within the same photolithographic write field. The top traveling-wave electrode structure is overlaid across layers based on this mark, forming a predetermined spatial matching relationship with the write field splicing region. This invention can solve the problems of optical scattering loss caused by long-distance bottom waveguide field-separated exposure splicing and the limited accuracy of cross-layer overlay after heterogeneous bonding, and achieves precise overlay positioning of the cross-layer traveling-wave electrode.

A system for measuring roughness of a core sidewall of an optical waveguide based on mode excitation is provided, in which an optical waveguide to be measured is arranged between a few-mode long-period fiber grating and an optical power meter; the laser beam is incident on the optical waveguide to be measured after passing through the few-mode long-period fiber grating, and then is incident on the optical power meter after being subjected to a scattering loss caused by the roughness of the core sidewall of the optical waveguide to be measured; and the processor is configured to calculate an equivalent value of the roughness of the core sidewall according to the output power detected by the optical power meter, the output modes of the few-mode long-period fiber grating and the mode of the optical waveguide to be measured.

This invention discloses a partitioned scattering optical lens for myopia control and its design method, applied in the field of optical technology. It aims to solve the problem in existing technologies where central visual quality and peripheral myopia control effects cannot be simultaneously achieved. The optical lens includes a central optical zone, a peripheral optical zone, and a smooth transition zone. The central optical zone has a low scattering coefficient and a high MTF, achieving a high modulation transfer function and low scattering loss. The peripheral optical zone has a high scattering coefficient and a low MTF, used to induce peripheral myopic defocus. The smooth transition zone achieves a continuous and gradual change in scattering coefficient to avoid abrupt visual changes and ensure visual comfort. The design method includes obtaining eye parameters, defining optical performance targets, designing microstructures, and performing simulation optimization. Through the above scheme, this invention effectively decouples central visual acuity and peripheral myopia control, ensuring high-definition vision, inhibiting myopia progression, and improving wearing comfort.

The application provides a resonator and a photonic chip, comprising: a micro-ring waveguide and a straight waveguide, a coupling section of the straight waveguide and the micro-ring waveguide, in the coupling section, the straight waveguide and the micro-ring waveguide have the same waveguide structure, the waveguide structure comprises: a first waveguide arm and a second waveguide arm, and there is a radiation slot between the first waveguide arm and the second waveguide arm; a side of the first waveguide arm facing the radiation slot is provided with a plurality of first grating slots arranged along the extension direction of the radiation slot; a side of the second waveguide arm facing the radiation slot is provided with a plurality of second grating slots arranged along the extension direction of the radiation slot; and the first grating slots and the second grating slots are one-to-one aligned. Thus, the second waveguide arm and the first waveguide arm in the waveguide structure of the coupling section can constitute a subwavelength grating slot waveguide with a continuous outer boundary. Since the outer boundary is continuous, mode disturbance and sidewall scattering can be effectively suppressed, so that the scattering loss of the resonator can be significantly reduced.

The invention provides a biochemical reaction optical signal detection device and a spherical micro-fluidic chip thereof, and relates to the field of optical signal detection. The detection device comprises a spherical micro-fluidic chip, a thermodynamic-fluorescence module and an optical matching detection element, the thermodynamic-fluorescence module comprises a thermodynamic-fluorescence first sub-module and a thermodynamic-fluorescence second sub-module, the spherical micro-fluidic chip is clamped up and down by the thermodynamic-fluorescence first sub-module and the thermodynamic-fluorescence second sub-module, and the optical matching detection element is connected with the spherical micro-fluidic chip through the thermodynamic-fluorescence first sub-module and the thermodynamic-fluorescence second sub-module. And the optical matched detection element penetrates through the thermodynamic-fluorescent second sub-module and reaches the cavity of the spherical micro-fluidic chip. The spherical micro-fluidic chip is arranged on the optical matching detection element, so that exciting light emitted into the spherical micro-fluidic chip from the optical matching detection element can excite an object to be detected for multiple times in the spherical micro-fluidic chip, the fluorescence excitation efficiency of the object to be detected is improved, meanwhile, the fluorescence scattering loss is reduced, and the signal-to-noise ratio and the sensitivity of a fluorescence detection system are improved.

The invention relates to the technical field of nuclear radiation detection, and discloses a nuclear radiation hot spot imaging device and method.The nuclear radiation hot spot imaging device comprises a scintillator, a collimation fixing cavity, a light guide and a photoelectric detector which are sequentially arranged in the axial direction, the outer surface of the scintillator is provided with a lens structure, and the lens structure is a cambered surface protruding outwards; the lens structure is used for focusing rays emitted by a nuclear radiation source into parallel fluorescent beams and enabling the parallel fluorescent beams to penetrate through the scintillator, and when the parallel fluorescent beams irradiate the scintillator, the scintillator emits an optical signal; a plurality of collimation light windows are arranged on the collimation fixing cavity; a convex mirror structure with an outer convex cambered surface is adopted, isotropically emitted fluorescence is focused to be in a state close to parallel fluorescence, and scattering loss is reduced; the collimation fixing cavity is matched with the convex lens structure, so that collimation incidence of parallel fluorescent beams can be ensured, the incidence direction is effectively restrained, stray radiation interference is avoided, and the measurement accuracy is improved.

The invention relates to the technical field of resonant cavities, in particular to a quasi-optical cavity-based powder material dielectric property separation type cylindrical resonant cavity, which comprises a box body, an upper cavity, a sample bin and a lower cavity are arranged in the box body, the upper cavity is of a cylindrical structure, the sample bin is made of flexible polytetrafluoroethylene, the top and the bottom of the sample bin are respectively provided with a magnetic attraction point, and the magnetic attraction points are arranged in the lower cavity. The top of the sample bin is magnetically connected with the upper cavity, and the bottom of the sample bin is magnetically connected with the lower cavity; the lower cavity is of a cylindrical structure, the surface of the lower cavity is sleeved with a heat insulation sleeve, and a wave-absorbing material layer is attached to the inner wall of the lower cavity. The diamond coating has a superhard characteristic and extremely low surface roughness, so that the scattering loss of electromagnetic waves on the inner wall of the cavity is remarkably reduced, heat generated by electromagnetic energy in the cavity can be quickly dissipated, and the influence of temperature fluctuation on a Q value is inhibited; the cavity is divided into an upper part, a middle part and a lower part which are connected through magnetic attraction points to form a modular quasi-optical cavity, and the single-mode purity can be achieved by combining the wave-absorbing material layer and high-precision machining.

The application provides a suspended optical mechanical system, comprising a first substrate block, a suspended waveguide, a suspended support beam, a plurality of support tether groups, a suspended detection mass and an optical cavity, wherein the suspended waveguide comprises a linear main body part extending along an X direction and a plurality of connection parts arranged in sequence and at intervals along the X direction, and the support tether groups are connected to the section of the suspended waveguide with the connection parts, the stability of the connection of the support tether and the suspended waveguide is increased, the width of the suspended waveguide at the connection parts is enlarged, the optical mode can be well limited in the waveguide, and the influence of the support tether on the optical mode is minimized. The tapered part of the connection part ensures the singularity of the mode in the process of light field transmission and slows down the change trend of the width of the suspended waveguide, which is beneficial to reduce the scattering loss and further increase the quality factor. The connection part arranged on one side can ensure that the gap width between the suspended waveguide and the optical cavity is constant, thereby ensuring the optimal coupling efficiency.

The invention relates to the technical field of liquid crystal display devices, in particular to a reflective liquid crystal display panel, a preparation method of the reflective liquid crystal display panel and a reflective liquid crystal display device. The reflective liquid crystal display panel comprises a first substrate, a liquid crystal layer and a second substrate which are sequentially laminated, the cholesterol type liquid crystal composition comprises nematic liquid crystal, a hydrophobic first chiral compound and a hydrophilic second chiral compound, and the optical rotation of the first chiral compound is opposite to that of the second chiral compound; a hydrophilic interface is formed on the side, facing the liquid crystal layer, of one of the first substrate and the second substrate. The limitation that the theoretical reflectivity of a single-optical-rotation cholesterol liquid crystal does not exceed 50% is broken through, and the overall reflectivity and the display brightness are improved. As the components with different optical activities are vertically layered in the same liquid crystal continuous phase instead of forming an independent double-layer structure by means of external attachment, no obvious independent mechanical interface exists between the layers, the light scattering loss can be reduced, and the optical coupling efficiency can be improved.

The invention provides a method for calculating the connecting line height from the lowest scattering point of a troposphere to a receiving and transmitting antenna. The connecting line height from the lowest scattering point of the troposphere to the receiving and transmitting antenna is calculated. The spherical distance between the transmitting antenna and the receiving antenna is calculated; the prime unitary circle curvature radius of the earth reference ellipsoid at the transmitting antenna latitude and the receiving antenna latitude is calculated; the linear distance between the transmitting end and the receiving end is calculated; and the connecting line height from the lowest troposphere scattering point to the receiving antenna and the transmitting antenna is calculated. On the basis of the distance between the transmitting antenna and the receiving antenna and the included angle between the receiving antenna and the transmitting antenna, a mathematical model of the height between the lowest troposphere scattering point and the connecting line between the receiving antenna and the transmitting antenna is provided, compared with a method of an ITU-R.P.617 proposal, the troposphere scattering transmission requirement is better met, and in troposphere scattering loss prediction, the troposphere scattering loss prediction accuracy is improved. And the calculation accuracy of parameters such as a scatterer dependency coefficient, elevation angle offset loss and antenna low-frame loss can be improved.

The invention discloses a channel modeling method and system, and relates to the technical field of communication, and the method comprises the steps: obtaining millimeter wave channel data, and reversely deducing a significant physical structure body; extracting scattering loss of the significant physical structure body; classifying the significant physical structure bodies; distributing geometric models and electromagnetic parameters to the classified significant physical structure bodies to obtain simplified physical structure bodies; carrying out scatterer distribution modeling on a non-significant physical structure body or a physical body structure with a complicated internal scatterer by adopting a statistical model to obtain a scatterer distribution modeling result; the system comprises an air-ground integrated dynamic measurement system, a data processing unit, a modeling engine unit and a machine learning training platform. According to the invention, efficient and accurate representation of a complex wireless propagation environment can be realized, and a future communication system can be converted from passive channel adaptation to active sensing and utilization of environment information.

The invention relates to the technical field of semiconductors, and discloses a polarization-independent and adiabatic optical power divider and a design method thereof. The polarization-independent and adiabatic optical power divider comprises a substrate layer and a waveguide core layer; the waveguide core layer comprises an input straight waveguide and an input conical waveguide connected with one end of the input straight waveguide; the first output conical waveguide and the second output conical waveguide are located on the two sides of the input conical waveguide in the length direction respectively, gaps are reserved between the first output conical waveguide and the input conical waveguide, and the conical directions of the first output conical waveguide and the second output conical waveguide are opposite to the conical direction of the input conical waveguide; the first output S-shaped bent waveguide and the second output S-shaped bent waveguide are respectively connected with the first output conical waveguide and the second output conical waveguide; wherein the input conical waveguide, the first output conical waveguide and the second output conical waveguide are arranged in parallel along the light propagation direction to form a conical staggered area. The adiabaticity of the optical power divider can be improved, the scattering loss of the device is reduced, the minimum feature size of the coupling area is increased, and the overall size of the device is reduced.

The invention provides a non-intrusive manufacturing method of a lithium niobate film waveguide, which belongs to the field of lithium niobate film optical waveguides, and comprises the following steps: preparing a periodically poled lithium niobate film wafer on an insulator as a substrate; cleaning the substrate, fixing the substrate on a spin coater, dropwise adding photoresist with the refractive index lower than that of lithium niobate crystals on the surface of the periodically poled lithium niobate film, and uniformly spin-coating to form a photoresist layer with the thickness of 100-2000nm; placing the substrate on a hot plate for pre-baking; aligning the mask plate of the single-mode ridge waveguide pattern with the substrate, and exposing in a photoetching machine by using ultraviolet light; after exposure is completed, the substrate is placed on the hot plate again for post-baking; developing the photoresist layer to form a ridge waveguide structure; and washing with isopropanol and blow-drying with nitrogen. According to the method, physical etching or cutting-up of the lithium niobate crystal is avoided, light scattering loss is reduced, the method is compatible with a mature semiconductor micromachining process, and large-scale production is facilitated.

The invention belongs to the technical field of MiniLED display packaging, and particularly relates to a high-performance water vapor blocking type COBMiniLED packaging structure and a packaging method. Comprising a substrate, a Mini LED chip array arranged on the substrate, a composite packaging system covering the Mini LED chip array, an optical adjusting assembly cooperating with the composite packaging system, a white glue reflective layer and a pixel circuit framework connected with the Mini LED chip array. The splicing seam compensation structure based on optical modulation is designed, specifically, a special optical adhesive layer and reticulate pattern film composite structure is arranged at the splicing position of multiple modules, and a hollowed-out hole array for accurate calculation is machined in the optical adhesive layer. Wherein the distance between the hollowed-out holes is strictly controlled to be 0.8-1.2 times of the distance between every two adjacent Mini LED light-emitting units, through the structure, light propagation of the splicing seam area can be effectively guided, refraction and scattering losses of light at the splicing seam position are reduced, visual compensation of the splicing seam is achieved, a complex electronic compensation algorithm is not needed, and the system cost and complexity are reduced.

The application discloses a SiC@BN core-shell nanowire periodic array reinforced Si3N4 high-temperature wave-absorbing ceramic coating, which is composed of SiC nanowires, a BN shell layer and a Si3N4 ceramic matrix. The SiC nanowires and the BN shell layer are obtained through a chemical vapor infiltration process, and form a core-shell structure to obtain SiC@BN core-shell nanowires, which can avoid oxidation of the SiC nanowires and improve the dielectric constant of the SiC nanowires. The SiC@BN core-shell nanowires are arranged in a three-dimensional periodic array. The Si3N4 ceramic matrix is prepared through the chemical vapor infiltration process, and the Si3N4 ceramic matrix is uniformly filled in the pores between the SiC@BN core-shell nanowires. Through macro-micro multi-scale structure design, lattice distortion, stacking faults and interface defects are introduced in the micro scale to promote the absorption and attenuation loss of the incident electromagnetic wave, and the surface electric field coupling effect and multiple scattering loss mechanism are introduced in the macro scale to realize the widening of the effective absorption band and the synergistic improvement of the electromagnetic wave absorption characteristics.

The present invention relates to methods and apparatus for determining propagation loss between a transmitter and a receiver using terrain and clutter data and / or the utilization of the determined propagation loss for managing spectrum usage. An exemplary method includes the steps of: determining a free space loss (FSL) for a propagation path extending from a first endpoint to a second endpoint, determining a clutter loss for a first portion of the propagation path, the first portion of the propagation path extending from the first endpoint to a horizon point which is located atop of clutter, determining a diffraction or tropo-scattering loss for a second portion of the propagation path extending from the horizon point to the second endpoint; generating a total loss for the propagation path based on the FSL, the clutter loss, and the diffraction or tropo-scattering loss; and making a spectrum usage decision based on the total loss.