In textile production, quality control and testing is the key to ensure the process and improve the efficiency. Defect of the knitting needles is the main factor affecting the quality of the appearance of textiles. Defect detection method based on machine vision and image processing technology is universal. This approach does not effectively identify the defect generated by damaged knitting needles and raise the alarm. We developed a knitting needle status monitoring setup using optical imaging, photoelectric detection and weak signal processing technology to achieve real-time monitoring of weaving needles’ position. Depending on the shape of the knitting needle, we designed a kind of Glass Optical Fiber (GOF) light guides with a rectangular port used for transmission of the signal light. To be able to capture the signal of knitting needles accurately, we adopt a optical 4F system which has better imaging quality and simple structure and there is a rectangle image on the focal plane after the system. When a knitting needle passes through position of the rectangle image, the reflected light from needle surface will back to the GOF light guides along the same optical system. According to the intensity of signals, the computer control unit distinguish that the knitting needle is broken or curving. The experimental results show that this system can accurately detect the broken needles and the curving needles on the knitting machine in operating condition.
An optical detecting technique to identify bio-aerosol particles is proposed in this paper by normalized fluorescence
value which correlates to its size and intrinsic fluorescence. With the bio-aerosol detecting system developed, we test and
analyze three types of aerosols, while each of them contains fluorescent microspheres of a certain size. The result
indicates that different fluorescent microspheres containing the same fluorescent substances have the same normalized
fluorescence voltage to unit particle size in diameter. The normalized fluorescence value of other species aerosols is
tested for comparing. The research results can be applied to identification of bio-aerosols preliminarily.
A new generation of Up-converting phosphor technology-based biosensors (UPT-based biosensor) has been developed
for immunoassay, where a kind of novel Up-converting phosphor (UCP) particle serves as the biological marker. Its
control system is based on a micro-computer control unit instead of a personal computer, which results in low power
consumption, high reliability and portability for field detection. By detecting the content of the UCP on the test strip, the
system figures out the concentration of the biological molecular of interest, which can be used in field examination of
biological analytes. In this paper, a series concentration of standard samples have been tested by the biosensor, which is
proved to have higher sensitivity (~ng/ml), higher stability (CV<3~5%), better linear relationship and an excellent
correlation (R2≥0.95). The UPT-based biosensor has stable, reliable and sensitive performances. It can meet the need of
various rapid bioassay applications.
A method to measure displacements based on Moire technique and polarization modulation is presented and analyzed with Fourier transform and Jones matrix in this paper. A collimated laser beam illuminates a scale grating moved in the direction perpendicular to its groove. The scale grating is imaged on a two-phase index grating through a 4f system with an aperture in its frequency plane to form Moire fringes. The scale grating and the index grating have same grating period and their line and space ratio is 1:1. Two sections of the index grating are imaged on two parts of a bi-cell detector through a telecentric system, thereby the displacement of the scale grating can be obtained by detecting the Miore signals on the detector. Before the index grating, a polarizer and a Savart plate are placed. In the telecentric system, a photoelastic modulator between two quarter-wave plates and an analyzer are arranged. Thus the polarization modulation of the Moire signals is realized. The polarization modulation improves the measurement accuracy of the displacement. The analysis shows the displacement measuring method is of nanometer accuracy. In experiments, we verified the feasibility of the method. The repeatability of the method was less than 12nm.
A miniature optical sensor for laser particle counter is described, and some calculated and test results are reported in this paper. A reflective spherical mirror coated with highly reflective optical film is applied as collecting element for scattered light, and a PIN photodiode with high performance is used as the photo-detector. A band-pass preamplifier is used to eliminate lower-frequency electromagnetic interference from external environment, as well as to filter high-frequency components from electronic noise. An air sampling system can provide a very constant flow rate. The smallest particle diameter of the optical sensor is 0.3 microns with a signal-to-noise ratio exceeding 2:1.
The performance inspection of focusing optics, such as focusing lens and focusing assemblies, is of great importance in the machining of optical elements, alignment and regular maintenance of optical facilities. Currently, however the interferometric method and the knife-edge method used normally for the measurement of the large-aperture surface have limitations for the test in the large optical equipment. To solve the problems, a scanning Hartmann inspection apparatus based on the Hartmann principle for focusing optics performance test has been developed. In this paper, the experimental setup and test principle are described, experimental results and analysis are given, and the improvement plan further to obtain better test capability is briefly presented in the end.
An up-converting phosphor technology-based biosensor (UPT-based biosensor) has been developed for immunoassay using Up-converting phosphor (UCP) as the biological marker. The UPT system has realized quantitative detection and has good ability to meet the need of some emergencies. High sensitivity (nanogram/ml), good linear response characteristics and an excellent correlation (R2greater than or equal to 0.95) have been verified by quantitative detection results. The sensitivity of the UPT-based biosensor is better than that of the indirect hemagglutination test in the practical application. All the results are comparable with that obtained by Western Blot detection.
A fiber-optic biosensor is developed based on the principle of evanescent wave while light propagates in optical fiber. The biosensor uses a red laser diode at 636.85 nm for exciting Cy5 fluorescent dye. Sensitivity limit of 0.01 nnmol/l is obtained from the detection of serial Cy5 solutions with various concentrations. In log-to-log plot, excellent linear response characteristic is seen in the Cy5 concentrations ranging from 0.01 nmlo/l to 100 nmol/l. And a good result of signal-to-noise ratio of 4.61 is obtained when the biosensor is used to measure Legionella pneumophila solution of 0.01 μmol/l. All the results are comparable with those that are obtained by a commercial biochip scanner GeneTAC 1000.
A laser-diode based optical sensor for laser particle counter is described,nd some calculated and test results are reported in this paper. A low-powered 650 nm laser diode is used as the light source. The optical system of the sensor is a right- angle scattering optics, which consists of an illumination system and a wide-angle collection system for scattered light. The sensor features high counting efficiency and high signal- to-noise ratio for smaller particles.
High-resolution contact lithography was conducted by both 248-nm KrF and 193-nm ArF excimer lasers on PMMA resist. The resist thickness is about 0.5 (mu) . Resolution of 0.5- (mu) lines and spaces was obtained on PMMA resist after KrF excimer laser exposure and subsequent wet development. No self-developing photoetching was observed. However, with ArF excimer laser as the exposure light source, resolution of 0.3-(mu) lines and spaces was obtained on the same resist by direct photoetching under high exposure dose combined with subsequent conventional wet developing process.
Intensity distribution on the wafer plane in contact printing system under off-axis illumination is derived based on the amplitude analytic expression for Fresnel-Kirchhoff diffraction. Numerical simulations have been done under various conditions. Resolution enhancement effects by off-axis illumination and its application are analyzed.
We have designed and constructed a white light optical sensor for optical particle counter (OPC). The optical system of the sensor is a right-angle scattering type optics. It consists of an illumination system and a collection system for scattered light. A large illuminating aperture angle of 24 degrees is obtained by applying an aplanatic singlet in the illumination system, and a large collecting aperture angle of +/- 44 degrees is achieved by a spherical mirror. With the two large apertures, high signal-to-noise ratio and good monotonic light scattering response have been gained.
We have fabricated a large aperture random phase plate (RPP) in Chinese K9 glass substrate for target-plane laser beam smoothing at 1.06 micrometer wavelength, by using large aperture photolithography and dilute HF etching processes. The RPP's clear aperture is (phi) 250 mm. The measured average step height is 1.060 micrometer, which has a relative standard deviation of 1.24% at 5 locations on the RPP to the theoretical value. A focal spot with very sharp edges and nearly flat-top overall envelope intensity distribution is obtained at the focal-plane of a focusing lens. These results show that our fabrication techniques for RPP is effective, and is easily scaleable to even larger apertures.