7746 results about "Refractive index" patented technology

The invention discloses a heat shrink tube detection method based on image recognition, particularly relates to the technical field of electric power material defect detection, and is used for solving the problems of defect contour distortion, positioning deviation and insufficient classification precision caused by optical ghost interference in heat shrink tube detection. A mapping relation of light refraction paths is established based on brightness gradient difference and refractive index difference, theoretical ghost interference fringes are generated by dynamically adjusting optical path difference of an interferometer, and abnormal areas deviating from theoretical distribution are screened; meanwhile, light source incident angle optimization and defect displacement calculation are combined, residual ghost interference is eliminated, finally, accurate classification and positioning of defects are achieved through multi-dimensional matching of geometric parameters and historical defect data, complex algorithm dependence is reduced while the detection precision is improved, and the real-time detection requirement of an industrial production line is met.

The invention relates to the related technical field of semiconductor wafers, in particular to a full-automatic wafer film thickness detection method and system based on spectral reflection, and the method comprises the steps: obtaining a wafer surface reflection spectral signal, and extracting spectral feature information and wavelength parameters; identifying a polarization characteristic parameter and an interface interference characteristic parameter, introducing the wavelength parameter as an adjusting variable, determining a wavelength dependence term, and generating a global film thickness distribution map, thereby solving the problems that in a detection scene with a multi-layer film or a rough interface, the influence of an incident light polarization state on a reflection signal is not fully considered, the reflection signal characteristic extraction is distorted, and the detection accuracy is poor. According to the method, the technical problem that the film thickness obtained through reflection characteristic backstepping deviates from the actual film thickness is solved, polarization characteristic parameters and interface interference characteristic parameters are recognized, the thickness of each detection point is determined after the film refractive index is corrected, the thickness detection precision is effectively improved, and the influence of spectral signal noise and interface interference is reduced; the technical effect of accurately presenting the global film thickness distribution of the wafer film is achieved.

The invention relates to a multi-layer composite black film and a preparation method thereof. The multi-layer composite black film is formed by sequentially stacking a base material layer, a multi-layer film system and a top covering layer, the multi-layer film system is formed by alternately stacking a plurality of absorption layers and a plurality of oxide layers, the number of the layers is 7-30, an initial layer is an oxide layer, the refractive indexes of the oxide layers are the same (1.4-1.5), the thickness ratio of the oxide layers to the absorption layers is larger than 2, and the thickness ratio of the top covering layer to the absorption layers is larger than 1. And the thicknesses of the two layers are increased and then reduced from the substrate layer to the top covering layer. A buffer layer with gradually changed oxygen content is arranged between the oxide layer and the absorption layer, and both the oxide layer and the top covering layer are made of silicon dioxide. The preparation method comprises the following steps: providing the substrate layer, alternately depositing the absorption layer and the oxide layer by using a magnetron sputtering or electron beam evaporation process to form a multilayer film system, then forming the top covering layer, controlling parameters such as vacuum degree, power, temperature and the like during deposition, and forming the buffer layer in the same cavity. The multilayer composite black film has the inner surface reflectivity of less than 1% and the appearance surface reflectivity of less than 5%, and is simple in structure and low in preparation cost.

The invention relates to the technical field of ophthalmology optics, in particular to a myopia control lens optical system integrating ray tracing and aberration correction, which comprises a wavefront phase acquisition module, a wavefront feature statistics module, a ray tracing simulation module, a microstructure form regulation and control module and a feedback control module. According to the method, accurate identification and datamation description of wavefront change under a dynamic vision condition can be realized by acquiring an eyeball wavefront phase matrix, performing gridding partition analysis and extracting local phase offset amplitude and time sequence characteristics, and a light propagation path model is constructed by combining statistical characteristics of an abnormal wavefront region; the self-adaptive compensation is carried out on the local focus deviation, and the spatial distribution optimization of the refractive index and the curvature is further realized based on the microstructure form regulation and control, so that the real-time matching of the optical parameters and the wavefront state is maintained during the processing and use of the lens, and therefore, the imaging quality is stabilized, the visual definition is improved, and the myopia control reliability is enhanced.

The invention discloses a method for detecting probiotics in fermented rotten vegetable feed based on the Internet of Things, and relates to the technical field of microbiological detection, and the method comprises the following steps: obtaining complete echo signal time sequence data, and carrying out high-frequency sampling on an echo signal time sequence by a sliding time window with a fixed length, and constructing a three-dimensional optical signal transient feature vector. According to the method, the transient feature vector of the three-dimensional optical signal is constructed, and a disturbance residual error and time sensitive weight mechanism is introduced, so that the abnormal disturbance of the optical signal is accurately recognized; by combining the optical interference index and the dynamic sampling window adjustment strategy, the refractive index mutation area is automatically avoided, the sensing misjudgment and data distortion are avoided, the detection stability and accuracy of the probiotic activity state in the fermentation environment are remarkably improved, and the intelligent monitoring capability of the feed quality is enhanced.

The invention provides a wavelength deviation compensation method and system for rapid wavelength analysis of a far-end fiber bragg grating, and relates to the technical field of fiber bragg grating sensing, and the method comprises the steps: collecting grating reflection spectrum signals of different transmission distances, carrying out frequency domain transformation to separate phase components, and building a mapping relation between the transmission distance and dispersion cumulant; calculating an initial wavelength offset estimation value; identifying a refractive index section, and establishing a segmentation compensation coefficient; constructing a wavelength-strain-temperature three-dimensional space, and optimizing a compensation coefficient according to the trajectory curvature; and updating the compensation coefficient according to the residual gradient. The wavelength analysis precision of the far-end fiber bragg grating can be improved, and the influence of dispersion on measurement is reduced.

The invention discloses a refractive index structure constant adaptive forecasting method and system based on atmospheric turbulence multi-scale characteristics. The method comprises the following steps: 1, measuring and preprocessing an atmospheric refractive index structure constant; 2, constructing a spatial-temporal feature extraction module of an atmospheric turbulence refractive index structure constant; 3, learning a dependency relationship representing a long-time sequence by using a gating mechanism, and constructing a long-time correlation feature extraction module; 4, capturing dependency relationships of different times through convolution kernels of different time steps, and constructing a short-time correlation feature extraction module; 5, designing a self-adaptive turbulence multi-scale feature fusion module which comprises three groups of bidirectional cross attention modules to realize alignment and fusion among different turbulence feature extraction modules; and introducing a gating mechanism, performing dynamic control and feature selection on output information streams of the three groups of bidirectional cross attention modules, and simulating the change of importance of different scale features of turbulence along with conditions to obtain a predicted value.

The invention discloses a liquid medicine foreign matter detection method and system based on machine vision, and the method comprises the steps: obtaining multiband spectral data of a liquid medicine sample, and carrying out the normalization processing to generate a liquid medicine background standard spectral feature template; comparing the refractive index spectral characteristics of the template and the foreign matter-containing liquid medicine, and recording the surface roughness scattering mode and polarized light reflection angle change data of a foreign matter area; calculating a spectrum peak displacement quantized value according to the polarized light data, and extracting foreign matter edge spectrum gradient information in combination with a threshold value; calculating a transparency spectral attenuation coefficient based on the edge gradient information, and obtaining spectral contrast enhancement factors of different foreign matters in combination with the spectral response characteristic data; and if the enhancement factor does not reach the standard, adjusting the spectrum correction parameter and recalculating, fusing the scattering mode and the multi-angle incident spectrum response result to carry out consistency verification, and obtaining a final identification result containing the foreign matter material type and the danger level. The method can improve the drug detection accuracy and guarantee the drug quality safety.

The invention relates to an error compensation method of a birefringence self-calibration laser level meter, in particular to the field of laser level meters, and aims to improve the precision of the laser level meter by combining a birefringence effect, physical modeling and neural network optimization. Firstly, temperature data are collected in real time, Kalman filtering is used for noise reduction, and accurate data are provided for physical modeling; then, through physical constraints such as a heat conduction equation and a Jones matrix, a coupling relation between the temperature gradient and optical parameter changes is established; then, dynamically optimizing the refractive index correction by using a physical information neural network to avoid an overfitting problem; and finally, calculating optical path difference compensation by using a hardware accelerator, correcting a system error in real time, and feeding back and adjusting a network weight. According to the method, the precision and the stability of the laser level meter in an environment with relatively large temperature change are effectively improved.

The invention provides a laser positioning method for improving gemstone cutting precision, and belongs to the technical field of gemstone cutting laser positioning. A gemstone crystal refractive index tensor model and a ray tracing algorithm are established to simulate a propagation path of light in a gemstone; a thermo-optic effect prediction model is adopted to predict a focus drift distance according to temperature distribution and laser power data and calculate wavefront predistortion phase distribution for compensation, and a zero-vibration input shaping filter is designed for a galvanometer scanning system to suppress residual vibration. A composite control strategy that feedforward control compensates inertia lag and feedback control corrects position errors is adopted to drive a galvanometer, the inherent frequency of a system is recognized through spectral analysis, and the scanning frequency is adjusted to avoid resonance. The technical problem that in the long-time machining process, due to the thermo-optic effect and vibration of a galvanometer scanning system, the laser focus point position generates accumulated drifting, and the cutting precision is reduced is solved.

The invention discloses a slant path atmospheric turbulence phase screen generation and light field transmission simulation method. Belongs to the technical field of satellite-ground laser communication. The method comprises the following steps: firstly, establishing a three-layer height spectrum model in a slant-range atmospheric turbulence environment, then generating an initial field suitable for vacuum and turbulence environments by using an angular spectrum method, and generating n corresponding random dynamic phase screens according to atmospheric turbulence characteristics of different heights on a slant-range path and distribution characteristics of atmospheric wind speed. Superposing the initial field and the first phase screen, performing two-dimensional Fourier transform, and performing inverse Fourier transform on the transform field by using an angular spectrum method to obtain field distribution in front of the next phase screen; and repeating the process to pass through n phase screens in sequence, and finally obtaining the output field distribution of the uplink and the downlink. The method can effectively simulate the effects of refractive index fluctuation, wavefront distortion, light intensity flicker and the like caused by oblique-range atmospheric turbulence, and provides important theoretical support and application value for researching oblique-range laser transmission characteristics.

An organic light-emitting device comprises an anode, a cathode and an organic layer formed between the anode and the cathode, and the organic layer comprises a hole injection layer, a hole transmission area, an electron blocking layer, a light-emitting area and an electron transmission area. The hole transport region comprises a first material and a second material, the first material and the second material are sequentially evaporated to form two hole transport layers, and the first material is selected from a compound shown in the formula 1; and the second material is selected from a compound shown in a formula 2. According to the invention, the first material with a high refractive index is used as the first hole transport layer, the second material with a low refractive index is used as the second hole transport layer, and the structures of the first material and the second material are respectively limited at the same time. The invention overcomes the limitation of a single material or a simple mixed material in the aspects of hole transport and luminous efficiency. .

The invention discloses an image recognition and correction system based on an optical model and environment perception, and relates to the technical field of image processing, and the system comprises an environment perception module which is used for collecting multi-medium refractive indexes, interface three-dimensional forms and initial image data through a refractive index sensor, a three-dimensional laser scanner and a visual camera; an environment perception data set is formed through dynamic correction and multi-source fusion; the optical model is constructed on the basis of environment sensing data, the light propagation path is calculated in combination with the interference compensation sub-model, and the interference compensation sub-model can quantify the interference influence by analyzing related data acquired by the environment sensing module for interference factors such as impurities and temperature gradient in a medium, so that the interference compensation precision is improved. The compensation term is generated and fused into the light propagation equation, so that the light propagation path is corrected, the calculation accuracy of the light propagation path is ensured, a firm and reliable data support is provided for subsequent image recognition and correction, and the precision and quality of image recognition and correction are improved.

The invention provides a multi-frequency adaptive unmanned aerial vehicle spectrum detection method and system, and the method comprises the steps: extracting the spatial and temporal distribution characteristics of carbon particle concentration and temperature gradient intensity based on a real-time environment data set, determining the attenuation coefficient distribution of different frequency band signals in a current environment, and obtaining a frequency band sensitivity analysis result; on the basis of a frequency band sensitivity analysis result, identifying a frequency band range which is most seriously influenced, and generating a signal data set which is optimized according to frequency bands; according to the signal data set optimized in different frequency bands, in combination with turbulence energy spectrum distribution and refractive index disturbance intensity, determining a random interference mode of a fire scene turbulence field on unmanned aerial vehicle detection signals and frequency dependence of the random interference mode; and adjusting the working frequency range of the spectrum detection equipment according to the frequency self-adaptive correction propagation path data set, and generating a multi-band collaborative optimization detection parameter set.

The invention discloses a composite optical film with a polarization function, a preparation method and application thereof. The composite optical film comprises a transparent substrate layer, and a buffer layer, an oriented calcite crystal layer and an anti-reflection layer which are laminated on one side of the transparent substrate layer. Wherein the oriented calcite crystal layer is obtained by coating a superparamagnetic modified calcite crystal composite material suspension on the surface of the buffer layer, inducing optical axis oriented arrangement through a magnetic field and performing UV curing; the buffer layer is obtained by co-extruding a cycloolefin polymer and a polyurethane acrylate mixture, and a thermal expansion coefficient transition system is formed; the anti-reflection layer is composed of nano-porous titanium dioxide with the refractive index changing from 1.8 to 2.3 in a gradient mode, and a refractive index gradient structure is formed. According to the composite optical film, the polarization efficiency and the light transmittance of the composite optical film are improved and the industrial stability is improved through the design of the polarization functional layer in which the calcite nanocrystals are directionally arranged under the induction of a magnetic field and in combination with the gradient refractive index scattering layer.

The invention provides a home overall design method and system based on virtual reality. Wherein indoor environment data are collected in real time in a spatial gridding mode through a distributed temperature and humidity sensor array and a multispectral illumination sensor, and heterogeneous data are fused by using a spatial topology association engine to generate a three-dimensional environment parameter set. And based on the space coordinate weight matrix of the parameter set, driving a micro-electro-mechanical execution unit of the dynamic optical reflection film layer to adjust the surface inclination angle and the refractive index so as to form an optical reflection characteristic distribution diagram. And a three-dimensional light field model dynamically linked with physical illumination distribution is further constructed in the virtual scene, adaptive compensation operation of temperature and humidity parameters is triggered in real time according to physical space illumination intensity changes, characteristic parameters of the reflecting film layer are synchronously and reversely regulated and controlled, and a closed-loop control link is formed. According to the technical scheme provided by the invention, the full-dimensional precise synchronization of the optical characteristics of the material, the temperature and humidity influence and the illumination distribution in the home design scene is realized.

The invention discloses a photovoltaic POSS (polyhedral oligomeric silsesquioxane)-containing antireflection film coating liquid and a preparation method thereof, the coating liquid comprises the following raw materials in parts by weight: 80-100 parts of modified emulsion, 10-15 parts of modified graphene, 3-5 parts of sodium dodecyl benzene sulfonate, 1-3 parts of triethylene tetramine and 40-60 parts of deionized water, a modified additive in the coating liquid contains a polyhedral oligomeric silsesquioxane structure, the polyhedral oligomeric silsesquioxane structure can form uniformly-distributed nanopores and is matched with a two-dimensional honeycomb lattice structure in the graphene oxide, the surface roughness can be increased, the microstructure can scatter incident light and reduce specular reflection, so that the surface light transmittance is improved, and meanwhile, the modified additive molecule contains a fluoroalkyl structure, so that the surface light transmittance is improved. The fluoroalkane has a high refractive index, so that light reflection can be reduced, and the light transmittance is further improved.

The invention discloses a far-infrared band optical thin film, a preparation method thereof and an optical element, and relates to a far-infrared band optical thin film technology, the far-infrared band optical thin film comprises a substrate, a front band-pass film system and a back cut-off film system; wherein the front band-pass film system is located on one side of the substrate, and the back cut-off film system is located on the other side of the substrate; the far infrared band optical thin film is prepared by alternately depositing lead telluride serving as a high-refractive-index thin film material and cadmium telluride serving as a low-refractive-index thin film material. The far infrared band optical thin film can cut off the band with the wavelength smaller than 4 microns, and the average transmittance is 0.23%; anti-reflection is carried out at the wave band of 5-50 microns; the moisture-resistant performance is excellent.

The invention belongs to the field of production control, and particularly discloses a control method of a thick-wall optical product precision injection molding hot runner system, which comprises the following steps of: acquiring mold geometric data of local thickness distribution in a mold-containing cavity along a melt flowing direction, calculating theoretical cooling time constants of each region by combining material thermophysical parameters, and calculating the cooling time constant of each region; establishing a thickness-cooling rate mapping relation model; predicting the time when the melt reaches each area and the effective cooling time according to an injection time sequence; solving a temperature compensation value of a heating area corresponding to the hot runner by taking the minimum final temperature variance when the key area is ejected as a target; and finally, dynamically applying a compensation value according to a time sequence before the melt arrives, and withdrawing / adjusting after region filling is completed or a pressure maintaining stage is entered. The invention can balance the temperature field of the mold cavity, reduce the refractive index gradient and shrinkage defect, improve the optical performance and yield of the product, and is suitable for precise injection molding of the thick-wall optical product.

The invention relates to the technical field of image segmentation, in particular to a water surface floating object area image segmentation method based on edge calculation, and the method comprises the steps: analyzing a time sequence image data flow into an RGB frame sequence; suppressing high-frequency illumination noise by using a space attention mask, and extracting a target correlation feature tensor; constructing an optical path model based on a medium refractive index, resolving a theoretical characteristic offset vector and mapping the theoretical characteristic offset vector into a sampling offset field; the deformable convolution is guided to execute feature alignment reconstruction, and a geometric coherence feature map is generated; and inputting a deep network to carry out pixel division and physical mode characterization, and outputting a segmentation result in combination with fluid divergence features. According to the method, through a feature suppression and refraction reconstruction mechanism, the problem of feature topology breakage under strong light and cross-medium distortion is solved under the edge end computing power constraint, and high-fidelity region segmentation is realized.

The invention is suitable for the technical field of filters, and particularly relates to a manufacturing method of a linear gradient filter and the linear gradient filter. The manufacturing method of the linear gradient filter comprises the following steps that a glass wafer serves as a substrate, and a lower reflecting layer is plated on the surface of the glass wafer; wherein the lower reflecting layer is formed by alternately stacking a plurality of layers of low-refractive-index materials and a plurality of layers of high-refractive-index materials; coating a resonant cavity layer on one side, far away from the glass wafer, of the lower reflecting layer through a stepped coating process; plating a reflecting layer on one side, far away from the glass wafer, of the resonant cavity layer; and plating a long-wave-pass layer on one side, far away from the glass wafer, of the upper reflecting layer and in an area larger than the central wavelength to obtain the linear gradient filter. Compared with the prior art, the linear gradient filter provided by the invention is better in spectral resolution in a long wave band, smaller in energy difference of channels, excellent in wavelength selection performance and capable of being applied to spectrum applications such as a miniaturized infrared spectrometer and the like.

The invention provides an optical measurement method and device, and belongs to the technical field of optical measurement, and the method comprises the steps: starting a light source with the wavelength changing dynamically to generate a sweep frequency optical signal; dividing the light into a measuring beam and a reference beam by using a light splitting component, guiding the measuring beam to irradiate a target to be measured and then return along the same path, and guiding the reference beam to enter an optical component of which the optical path changes along with the wavelength and then return; based on the low-coherence characteristic of the light source, when the optical paths of the two light beams meet the interference condition, detecting an interference signal by using a sensing component; the optical path difference is determined according to time information in the interference signal, and the thickness of each reflection interface is calculated by combining refractive index data of a target to be measured. Different from the traditional low-coherence interference measurement which depends on a motor and the like to control the movement of a reflector, the method avoids the limitation of mechanical driving on the measurement frequency, and achieves the high-speed optical thickness measurement.

The invention discloses a high-refractive-index nano-composite optical adhesive and a preparation method thereof, and belongs to the technical field of optical transparent adhesives. The optical adhesive is prepared by taking a polyurethane acrylate oligomer with a specific structure as matrix resin, introducing surface-modified barium titanate and zirconium oxide core-shell nanoparticles as a functional filler, and matching with an active diluent, a photoinitiator and a silane coupling agent in a specific proportion. Through the design of the core-shell structure, the core problems that the high-refractive-index nanoparticles are easy to agglomerate in an organic resin matrix, the dispersion stability is poor and the bonding force with a matrix interface is weak are effectively solved. The prepared optical adhesive has a refractive index of more than 1.65, a light transmittance of more than 99% and a haze of less than 0.3% after being cured, has excellent bonding strength, weather resistance and long-term use stability, and is especially suitable for precise lamination of high-end display devices (such as OLEDs (Organic Light Emitting Diodes) and micro-lens arrays).

The embodiment of the invention provides an anti-dazzle low-reflection optical film and a preparation method and application thereof, and relates to the field of optical films. The anti-dazzle low-reflection optical film comprises a base material layer, an anti-dazzle layer and a low-reflection layer which are sequentially stacked from bottom to top, the low-reflection layer contains low-reflection particles, and the anti-dazzle layer contains organic anti-dazzle particles and inorganic particles. The mass concentration of the organic anti-dazzle particles close to the base material layer is larger than the mass concentration of the organic anti-dazzle particles close to the low-reflection layer, the mass concentration of the inorganic particles close to the base material layer is smaller than the mass concentration of the inorganic particles close to the low-reflection layer, and the refractive index of the low-reflection particles is larger than the refractive index of the inorganic particles and smaller than the refractive index of the organic anti-dazzle particles. Seen from the direction from the low-reflection layer to the base material layer, the refractive indexes of all the layers are gradually increased. According to the anti-dazzle low-reflection optical film and the preparation method and application thereof, the optical film achieves high haze and low reflectivity and can be applied to a strong light environment.

The invention discloses a single-groove type photonic crystal fiber sensor based on surface plasma resonance. The single-groove type photonic crystal fiber sensor structurally comprises a fiber core and a perfect matching layer wrapping the fiber core, and circular air holes which are arranged periodically and are different in size are formed in the fiber core; the fiber core is provided with a groove channel, and the lower surface of the groove channel is coated with a gold film and a titanium dioxide film. A loss spectrum is obtained through calculation, and then the wavelength of the surface plasma formant and the sensitivity of the sensor are calculated. The refractive indexes of the to-be-detected analysis liquid sample are different, and the wavelengths of the resonance peaks of the transmission loss spectrum are also different. The refractive index range of a to-be-detected analysis liquid sample of the sensor is 1.39-1.4, the sensitivity of 11000 nm / RIU and the resolution of 9.09 * 10 <-6 > RIU can be obtained, the sensitivity and the resolution of the sensor are superior to those of an existing sensor, and the sensor is simple in structure and easy to operate and has great application prospects in the fields of biosensing, environmental monitoring and the like.

The invention discloses a method and a device for correcting laser focusing aberration in a transparent material, and belongs to the technical field of laser processing. The method comprises the steps that a machining light path containing an object plane, an aspheric reflector and a 4F device is built in Zemax, the surface type of the aspheric reflector is optimized with the minimum focus aberration as the target, and a rise table is derived; an optical path difference and a laser phase are calculated through Matlab, and a phase diagram is generated; and an actual machining light path is built, and a phase diagram is loaded to achieve low-aberration machining. Simulation optimization and phase modulation are combined, aberration caused by refractive index difference is effectively counteracted, wavefront errors are reduced by 58%, the thickness of a machining damage layer is reduced by 70%, the method is suitable for various transparent materials, the machining precision and the material utilization rate are improved, and the method is suitable for high-precision laser machining scenes.

The invention is applicable to the technical field of concrete deformation measurement, and particularly relates to a non-contact concrete deformation testing system and method based on a laser ranging technology, and the system comprises a laser ranging unit which is provided with a double-frequency phase modulation laser, an optical transceiver antenna and a phase detection circuit; the environmental parameter acquisition unit comprises a temperature sensor, a humidity sensor and an air pressure sensor; and the data processing unit carries an atmospheric refractive index calculation module, a Kalman filtering algorithm and a three-level early warning module, and supports wired / wireless data transmission. The distance measurement precision is high, and the concrete micro-deformation monitoring requirement is met; non-contact characteristic: non-damage monitoring on the concrete surface is realized through a diffuse reflection target; intelligent data processing: structural deformation and environmental noise are effectively distinguished, and the early warning reliability is improved; automatic monitoring is achieved, and the manual inspection cost is greatly reduced.

The invention relates to the technical field of data processing, in particular to a real-time data monitoring and early warning method for the growth process of a VCSEL epitaxial wafer, which comprises the following steps: acquiring the refractive index of a material used by the epitaxial wafer at the current moment in the growth process of the VCSEL epitaxial wafer by using MOCVD (Metal Organic Chemical Vapor Deposition) equipment; determining the growth rate of the epitaxial wafer at the current moment; determining the mutation degree of the growth rate of the epitaxial wafer at the current moment; determining the correction mutation degree of the growth rate of the epitaxial wafer at the current moment; determining an early warning threshold value at the current moment; and monitoring and early warning of real-time data in the growth process of the VCSEL epitaxial wafer are realized according to the corrected mutation degree and the early warning threshold value. According to the method, accurate inversion of the growth rate and intelligent identification of mutation are realized, abnormal and normal process changes are effectively distinguished, the early warning threshold is adaptively adjusted, the false alarm rate is reduced, and the accuracy and practicability of VCSEL epitaxial growth monitoring are improved.

Sleep-aiding eyewear that prevents light which inhibits melatonin production from reaching the eye is described. The eyewear that is the object of the present disclosure has improved visibility over other methods of cutting off melatonin-inhibiting wavelengths of light, which enables the user to perform tasks, such as reading and typing, uninhibited. This is achieved in some embodiments using a Bragg grating comprising multiple layers of alternating reflective index material as a surface coating on the lens. This may be combined with lens-tinting, or antireflective coatings, in the eyewear. Furthermore, transition lenses which block melatonin-shifting light when there is a suitable external stimulus, such as blue light from a light emitting diode, are described. The presently described filters are also useful for electronic displays and functional light-transmitting materials.

A cover for an infrared detector and a method of fabricating the cover are disclosed. The cover comprises a wafer comprising a material such as silicon that transmits infrared radiation. The wafer has a first surface and a second surface opposite the first surface. An antireflective region is formed in the wafer to enhance transmission of infrared radiation through the cover. The antireflective region comprises a first plurality of antireflective elements such as moth-eyes formed in the first surface. The first plurality of antireflective elements are sized and shaped and arranged relative to one another to form a region of graded refractive index at the first surface so as to reduce the amount of infrared radiation reflected by the cover at the antireflective region. The cover comprises a wall extending from the first surface and surrounding the antireflective region. The wall comprises a plurality of layers of material deposited on the wafer so that, when the cover is bonded to a sensor substrate via the wall, a cavity is formed that encapsulates a sensor region of the sensor substrate. The depth of the cavity may be adjusted by depositing the plurality of layers of material with a combined thickness equivalent to the desired depth of the cavity. A second plurality of antireflective elements may be formed in the second surface to enhance the antireflective properties of the antireflective region.