339 results about "Wavelength filter" patented technology

A biometric device configured to be attached to a portion of a body of a user measures biometric data of the user. The device includes an optical emitter, a wavelength filter, an optical sensor and a processor, for sending a light to the body of a user, receiving light received from the user, filtering and processing it to measure biometric data of the user, including for example, heart rate and blood flow rate. In addition, the biometric device may include other sensors, such as a galvanic skin response sensor, an ambient temperature sensor, skin temperature, motion sensor, etc., to enable the biometric device to measure arousal or conductivity changing events, ambient temperature, user temperature and motion associated with the user. Additionally, information from each sensor may be used to further filter noise in one or more signals received by the sensors to provide biometric data to the user.

A system and a method of a transparent color image display utilizing fluorescence conversion (FC) of nano-particles and molecules are disclosed. In one preferred embodiment, a color image display system consists of a light source equipped with two-dimensional scanning hardware and a FC display screen board. The FC display screen board consists of a transparent fluorescence display layer, a wavelength filtering coating, and an absorption substrate. In another preferred embodiment, two mechanisms of light excitation are utilized. One of the excitation mechanisms is up-conversion where excitation light wavelength is longer than fluorescence wavelength. The second mechanism is down-conversion where excitation wavelength is shorter than fluorescence wavelength. A host of preferred fluorescence materials for the FC screen are also disclosed. These materials fall into four categories: inorganic nanometer sized phosphors; organic molecules and dyes; semiconductor based nano particles; and organometallic molecules. These molecules or nano-particles are incorporated in the screen in such a way that allows the visible transparency of the screen. Additionally, a preferred fast light scanning system is disclosed. The preferred scanning system consists of dual-axes acousto-optic light deflector, signal processing and control circuits equipped with a close-loop image feedback to maintain position accuracy and pointing stability of the excitation beam.

Flow rate measurement system includes two measurement regions 14,16 located an average axial distance .DELTA.X apart along the pipe 12, the first measurement region 14 having two unsteady pressure sensors 18,20, located a distance X.sub.1 apart, and the second measurement region 16, having two other unsteady pressure sensors 22,24, located a distance X.sub.2 apart, each capable of measuring the unsteady pressure in the pipe 12. Signals from each pair of pressure sensors 18,20 and 22,24 are differenced by summers 44,54, respectively, to form spatial wavelength filters 33,35, respectively. Each spatial filter 33,35 filters out acoustic pressure disturbances P.sub.acoustic and other long wavelength pressure disturbances in the pipe 12 and passes short-wavelength low-frequency vortical pressure disturbances P.sub.vortical associated with the vortical flow field 15. The spatial filters 33,35 provide signals P.sub.as1,P.sub.as2 to band pass filters 46,56 that filter out high frequency signals. The P.sub.vortical -dominated filtered signals P.sub.asf1,P.sub.asf2 from the two regions 14,16 are cross-correlated by Cross-Correlation Logic 50 to determine a time delay .tau. between the two sensing locations 14,16 which is divided into the distance .DELTA.X to obtain a convection velocity U.sub.c(t) that is related to an average flow rate of the fluid (i.e., one or more liquids and/or gases) flowing in the pipe 12. The invention may also be configured to detect the velocity of any desired inhomogeneous pressure field in the flow. The invention may also be combined with an instrument, an opto-electronic converter and a controller in an industrial process control system.

An omnidirectional imaging system comprising a reflective mirror for viewing object within a hemispherical field of view form a single virtual view point at the local center of said reflective mirror, a projector for projecting a light beam toward said reflective mirror, and a variable wavelength filter optically positioned between said projector and said reflective mirror for generating a pattern having a spatially distributed wavelength spectrum of said reflective mirror, where a generator responsive to the hemispherical image data for generating three-dimensional image.

Only the light at an overlapping wavelength of the transmission characteristics of at least two wavelength selecting filters is looped, and at least one of the wavelength selecting filters varies a selected wavelength. Since a loss due to the optical filters is small and there is not a loss caused by a highly reflecting film, the output of an external-resonator variable-wavelength laser can be increased. Optical circuit component (8) divides light input from external device (1) into at least two ports. Loop waveguide (11) interconnects at least ports (9, 10) divided by optical circuit component (8) in the form of a loop. At least two first wavelength selecting filters (12, 13) are inserted in series in a path of loop waveguide (11), and have periodic transmission characteristics on a frequency axis which are different from each other. At least one of first wavelength selecting filters (12, 13) varies the selected wavelength.

Flow rate measurement system includes two measurement regions 14,16 located an average axial distance ΔX apart along the pipe 12, the first measurement region 14 having two unsteady pressure sensors 18,20, located a distance X₁ apart, and the second measurement region 16, having two other unsteady pressure sensors 22,24, located a distance X₂ apart, each capable of measuring the unsteady pressure in the pipe 12. Signals from each pair of pressure sensors 18,20 and 22,24 are differenced by summers 44,54, respectively, to form spatial wavelength filters 33,35, respectively. Each spatial filter 33,35filters out acoustic pressure disturbances P_acoustic and other long wavelength pressure disturbances in the pipe 12 and passes short-wavelength low-frequency vortical pressure disturbances P_vortical associated with the vortical flow field 15. The spatial filters 33,35 provide signals P_as1,P_as2 to band pass filters 46,56 that filter out high frequency signals. The P_vortical-dominated filtered signals P_asf1,P_asf2 from the two regions 14,16 are cross-correlated by Cross-Correlation Logic 50 to determine a time delay τ between the two sensing locations 14,16 which is divided into the distance ΔX to obtain a convection velocity U_c(t) that is related to an average flow rate of the fluid (i.e., one or more liquids and/or gases) flowing in the pipe 12. The invention may also be configured to detect the velocity of any desired inhomogeneous pressure field in the flow. The invention may also be combined with an instrument, an opto-electronic converter and a controller in an industrial process control system.

The present invention relates to an optical cross connect unit comprising M wavelength separating sections for receiving multiplexed optical signals each having N kinds of wavelengths different from each other through M optical fibers, respectively, and for wavelength-separating each of the multiplexed optical signals into N optical signals, M optical reproduction relay sections each for conducting an optical reproduction and relay in a manner of making a conversion of each of the N optical signals, wavelength-separated in each of the wavelength separating sections, into an electric signal and then modulating it with a desired optical wavelength, a refill section for mutually refilling M sets of optical signals optically reproduced and relayed in the optical reproduction relay sections, a focusing section for focusing the M sets of optical signals refilled in the refill section, and a light source unit for supplying input lights having desired wavelengths to be modulated in the M optical reproduction relay sections. The light source unit includes N light sources for outputting lights having the N kinds of optical wavelengths, a multiplexing and branching section for multiplexing the lights from the N light sources to produce a multiplexed light having N kinds of optical wavelength components and further for branching the multiplexed light into MxN lights to output them as multiplexed and distributed lights, M wavelength filter sections for distributively receiving N multiplexed and distributed lights of the MxN multiplexed and distributed lights branched in the multiplexing and branching section to output N lights due to the passage of only arbitrary wavelengths of the N kinds of optical wavelengths, and a wavelength setting control section for setting optical wavelengths, which pass through the wavelength filter sections, so that they differ from each other. The N lights from each of the M wavelength filter sections are supplied as the input lights. In the case that many light sources are necessary for the modulation processing by modulators or the like, this optical cross connect unit is also suitable because of using given wavelengths from a small number of light sources for a lot of modulation processing.

The present invention relates to ophthalmic systems and coatings comprising a selective light wavelength filter, wherein said selective filter provides improved contrast sensitivity.

A system for temporal and spectral resolved detection of photon emission from an integrated circuit is disclosed. A DUT is stimulated by a conventional ATE, so that its active devices emit light. The signal from the ATE is also sent to the system's computer as a synchronization signal. The light emitted from the switching devices is passed through a wavelength filter. Selected bands of wavelengths are then passed to respective detector(s) and the detector(s) response with respect to the time correlated ATE stimulus is studied.

An optical path of infrared rays (see the broken lines in FIG. 1) is modified to a substantially U-like shape by a first reflecting mirror and a second reflecting mirror. An incidence angle of the infrared rays incident on the wavelength filter (an angle between the infrared rays incident on the surface of the wavelength filter and the line perpendicular to the surface of the wavelength filter) is nearly zero. For this reason, as compared with a conventional example, the influence of the incidence angle dependence of the wavelength filter can be reduced. As a result, the amount of the infrared rays reaching the light receiving unit through the wavelength filter is increased, thereby suppressing a decline in the detection accuracy of the gas component.

A VIS-NIR hyperspectral imaging filter has serial stages along an optical signal path with angularly distributed birefringent retarders and polarizers. The retarders can include active retarders such as tunable liquid crystal birefringent elements, passive retarders such as fixed retarders, and/or combinations thereof. Distinctly different periodic transmission spectra are provided by different filter stages, each having multiple retarders, in particular with some stages having broad bandpass peaks at wide spectral spacing and other stages have very narrow closely spaced peaks. The respective spectra include at least one tunably selectable band at which the transmission spectra of the filter stages coincide, whereby the salutary narrow bandpass and wide spectral spacing ranges of different stages apply together, resulting in a high finesse wavelength filter suitable for spectral imaging. The filter may be configured to provide faster switching speed and increased angle of acceptance and may operate in the rage of approximately 400-1100 nm.

A SWIR hyperspectral imaging filter has serial stages along an optical signal path with angularly distributed birefringent retarders and polarizers. The retarders can include active retarders such as tunable liquid crystal birefringent elements, passive retarders such as fixed retarders, and/or combinations thereof. Distinctly different periodic transmission spectra are provided by different filter stages, each having multiple retarders, in particular with some stages having broad bandpass peaks at wide spectral spacing and other stages have very narrow closely spaced peaks. The respective spectra include at least one tunably selectable band at which the transmission spectra of the filter stages coincide, whereby the salutary narrow bandpass and wide spectral spacing ranges of different stages apply together, resulting in a high finesse wavelength filter suitable for spectral imaging. The filter may be configured to provide faster switching speed and increased angle of acceptance and may operate in the rage of approximately 850-1700 nm.

An optical transmission device improved in quality and reliability of OADM function and permitting configuration of highly-flexible, economical OADM networks. A wavelength tunable filter variably selects a wavelength according to a control frequency. A filter controller applies the control frequency to the filter while scanning wavelength over an entire signal bandwidth, to detect, from a reference wavelength monitor signal supplied thereto, a reference control frequency which permits the filter to select a reference wavelength and according to which wavelength is matched. On receiving a wavelength selection request, the controller obtains a target control frequency from the reference control frequency and the position of a target wavelength relative to the reference wavelength, and applies the obtained frequency to the filter. A reference wavelength filter transmits the reference wavelength therethrough. A light-receiving element monitors the transmitted reference wavelength to generate the monitor signal.

The present invention relates to ophthalmic systems comprising a selective light wavelength filter, wherein said selective filter provides improved contrast sensitivity.

A wavelength division image measuring device that can divide a wideband incident light from a measurement object into a plurality of wavelengths with high selectivity to thereby measure these images simultaneously and collectively. Micro periodic irregular lattices are formed on a substrate 302. At this time, a plurality of microscopic element areas 101 with different lattice shapes and lattice periods are repeatedly arranged within a plane of the substrate 302. Next, a high refractive index material and a low refractive index material are alternately laid thereon so as to form a multilayer using a bias spatter method to thereby form a wavelength filter 301 with a photonic crystal structure. Thus, an array of the photonic crystal wavelength filters 031 with a sharp selectivity and different wavelength transmission characteristics can be obtained.

A manufacturing method of a wavelength filter includes the steps of: depositing on a substrate a lower clad layer and a core layer, each made from a polymer material; compressing the core layer with a mold to lithograph a pattern of the mold onto the core layer; stabilizing the lower clad layer and the core layer; separating the core layer from the mold; forming an upper clad layer on the core layer; and forming an electrode on the upper clad layer.

A SWIR hyperspectral imaging filter has serial stages along an optical signal path with angularly distributed birefringent retarders and polarizers. The retarders can include active retarders such as tunable liquid crystal birefringent elements, passive retarders such as fixed retarders, and/or combinations thereof. Distinctly different periodic transmission spectra are provided by different filter stages, each having multiple retarders, in particular with some stages having broad bandpass peaks at wide spectral spacing and other stages have very narrow closely spaced peaks. The respective spectra include at least one tunably selectable band at which the transmission spectra of the filter stages coincide, whereby the salutary narrow bandpass and wide spectral spacing ranges of different stages apply together, resulting in a high finesse wavelength filter suitable for spectral imaging. The filter may be configured to provide faster switching speed and increased angle of acceptance and may operate in the rage of approximately 850-1700 nm.