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In this paper, we present an industrial application of multispectral imaging, for density measurement of colorants in photographic paper. We designed and developed a 9-band LED illumination based multispectral imaging system specifically for this application in collaboration with FUJIFILM Manufacturing Europe B.V., Tilburg, Netherlands. Unlike a densitometer, which is a spot density measurement device, the proposed system enables fast density measurement in a large area of a photo paper. Densities of the four colorants (CMYK) at every surface point in an image are calculated from the spectral reflectance image. Fast density measurements facilitate automatic monitoring of density changes (which is proportional to thickness changes), which helps control the manufacturing process for quality and consistent output. Experimental results confirm the effectiveness of the proposed system.

There are several paradigms for color generation in reflective displays (e-Paper) including RGBW color filtering or stacked RGB or CMY. Theoretically, the highest white state reflectance and best color gamut are achieved by stacking three layers of pixels. However, stacking 3 layers induces significant optical losses especially at high resolution and typically does not allow for video operation. Therefore RGBW color filtering is currently preferred for higher resolution and single-layer e-Paper, but only provides color at 25% of the area and a maximum theoretical white reflectance of 50%. Presented herein is a new bi-primary color-system that cooperatively displays two complimentary colors inside a single sub-pixel, and therefore doubles the white state reflectance and color gamut for single-layer e-Paper. Also discussed are candidate e-Paper technologies that may be able to adopt the bi-primary color system, including possible advantages and challenges for each technology.

We have developed thin and light weight flexible EPD (electronic paper display) using QR-LPD technology. QR-LPD suits for flexible display because of its simple display structure (no TFT) and robust image holding property. Novel types of thin and light weight flexible electronic paper display are discussed. This technology can realize the "real paper like" flexible electronic paper.

Research on affordable point-of-care health diagnostics is rapidly advancing1. Colorimetric biosensor applications are typically qualitative, but recently the focus has been shifted to quantitative measurements2,3. Although numerous qualitative point-of-care (POC) health diagnostic devices are available, the challenge exists of developing a quantitative colorimetric array reader system that complies with the ASSURED (Affordable, Sensitive, Specific, User-friendly, Rapid and Robust, Equipment-free, Deliverable to end-users) principles of the World Health Organization4. This paper presents a battery powered 8-bit tonal resolution colorimetric sensor circuit for paper microfluidic assays using low cost photo-detection circuitry and a low-power LED light source. A colorimetric 3×3-pixel array reader was developed for rural environments where resources and personnel are limited. The device sports an ultralow-power E-ink paper display. The colorimetric device includes integrated GPS functionality and EEPROM memory to log measurements with geo-tags for possible analysis of regional trends. The device competes with colour intensity measurement techniques using smartphone cameras, but proves to be a cheaper solution, compensating for the typical performance variations between cameras of different brands of smartphones. Inexpensive methods for quantifying bacterial assays have been shown using desktop scanners, which are not portable, and cameras, which suffer severely from changes in ambient light in different environments. Promising colorimetric detection results have been demonstrated using devices such as video cameras5, digital colour analysers6, flatbed scanners7 or custom portable readers8. The major drawback of most of these methods is the need for specialized instrumentation and for image analysis on a computer.

We built a hyperspectral imaging apparatus using middle-infrared light of 8–14 μm, which has a strong ability to identify organic materials, and attempted visualization of the distribution of organic materials that could not be identified by a naked eye. For this purpose, we utilized a low-cost bolometer camera (Nippon Avionics co., ltd. C100V, Japan) for its easy availability rather than an expensive mercury cadmium telluride (MCT) array sensor. To compensate for the low sensitivity of this bolometer, we adopted a Fourier-type spectroscopic system (Aoi Electronics co. ltd., Japan) using an imaging interferometer devised by the Kagawa University, Japan; this interferometer has higher light-utilization efficiency than Michelson interferometers, which are used in popular interferometry techniques. In this study, 4 types of adhesives, 9 types of varnishes and more than 50 types of inks were put on Al plates of size 10 cm × 10 cm and were used as samples. Glossy paper for printing photos with an inkjet printer was also used as a sample. A 300 °C black body of size 15 cm × 15 cm was used as a light source. Spectra of 320 × 240 points were measured at a wavelength resolution of approximately 9 cm−1. The mirror was scanned only once. The measurement time was approximately 30 s. Hyperspectral images of adhesives, varnishes and inks on Al plate and paper were successfully measured. Spectra over a 5 × 5-pixel neighborhoods were averaged, and the averaged spectra were compared with those measured by a commercially available Fourier transform infrared (FTIR) spectroscopy. The averaged and measured spectra had absorption peaks at the same wavelengths. Furthermore, by analyzing the measured spectra, the distribution of substances invisible to the naked eye was visualized. Our results show that if low-absorbance organic materials are put on a high-reflectance surface such as an Al plate, the middle-infrared hyperspectral imaging could be measured using a bolometer. Additionally, hyperspectral imaging of high-reflectance paper, such as glossy paper, could also be measured. Because a bolometer camera is much cheaper than an MCT array, hyperspectral imaging with such a camera has many potential applications. Moreover, an imaging interferometer, with its high efficiency of light utilization, is very suitable for the purpose.

Given monochromatic infrared LED (light emitting diode) device best modulation current, frequency, distance to reach its maximum output power and improve the measuring accuracy of quantifier. Design a wavelength of 2.12 μm, 1.89 μm monochromatic infrared emissions and detection optical path, two monochromatic infrared lights which the photo source sends out after transmits the analyte across the same point to achieve the same point detection and improve the accuracy of the measurement. After the paper samples basis weight have carried out nondestructive testing, which was improved from the aspects of structure. By using the light source, halogen tungsten lamp, filter wheel, electrical equipment can be saved, and it can simplify the measuring system. The experimental results show that when measuring the thickness of the paper in the range, the relative error is within 1%.

The proliferation of digital information is leading to a wide range of applications which make it desirable to display data easily in many locations, all changeable and updateable. The difficulty in achieving such ubiquitous displays is the cost of signage, the cost of installation, and the software and systems to control the information being sent to each of these signs. In this paper we will talk about a networked system of such signs which are made from gyricon electronic paper. Gyricon electronic paper is a reflective, bistable display which can be made in large web sheets at a reasonable price. Since it does not require a backlight nor does it require power to refresh the display image, such technology is ideal for making signs which can be run on batteries with extremely long battery life, often not needing replacement for years. The display also has a very broad illumination scattering profile which makes it readily viewable from any angle. The basic operating mechanism of the display, its manufacturing technique, and achieved performance will be described, along with the description of a networked solution using many such signs controlled with system software to identify speakers and meetings in conference rooms, hospitality suites, or classrooms in universities. Systems will also be shown which are adapted to retail pricing signage and others which can be used for large format outdoor billboards.

The paper presents benefits of optical time-of-flight spectroscopy for the pulp and paper characterization. A semiconductor pulse laser and a streak camera as the photodetector were utilized in experimental part of research described in this paper. Distribution of the time of flight of photons through various kinds of wood pulp (e.g. pulp after mechanical treatment coming both fi-om tree species giving hard and soft wood and pulp after thermo-mechanical treatment) was measured. The pulp samples used in the measurements had consistency ranging from 0 to 5% of dry mass in the suspension. The influence of additives (kaolin, talc and calcium carbonate) present in the suspension on the time of flight distribution of photons was studied as well. Finally, dependence of the time of flight of photons through various kinds of the paper (i.e. newspaper, copy paper, and tissue) on the thickness of the sample was investigated.

Phenylketonuria is a genetic disease, which causes the metabolization disorder of phenylalanine, this disorder would damage the neural system of infants as a result of the accumulation of phenylalanine in blood. Therefore, it is of great importance to diagnose and treat phenylketonuria as early as possible for newborns. The aim of this paper is to develop a fluorescence detection system to measure blood phenylalanine concentration of new-born infants. In this design, a high luminance ultraviolet LED is used for excitation source, and a kind of bifurcated optical fiber assembly is applied for conduction of light. The excitation source is filtered and coupled into quartz fibers of the bifurcated fiber assembly for conduction of light to excite the fluorescence of phenylalanine in blood sample. The collected fluorescence is transmitted along the glass fibers of the assemblies and coupled to a photomultiplier tube. The fluorescence is filtered with 470~500 nm band-pass filter to subdue scattered excitation light and to limit the spectral width of the detected fluorescence. By the comparison with a standard instrument, the new system with low power consumption, low cost and small size is also proven sensitive and accurate, which meets the demand of clinical phenylketonuria screening.

This paper studies the correlation between the time-of-flight (TOF) of laser pulses and paper density, basis weight, thickness and the beating of pulp. Paper samples made from unbeaten and beaten pulp were compressed from 500kg/m3 to 1100kg/m3 and laser pulses were shot through them during pressing. Changes were observed in the thickness of the samples and in the TOF of the laser pulses. The results show that TOF decreases during comrpession. This indicates that distances between the various scattering surfaces decrease. This phenomenon becomes more pronounced as the basis weight increases. The beating of the pulp before papermaking increases the number of scattering surfaces, thus broadening the laser pulse and causing delay. These two effects cannot be separated with the equipment used. Papers made from different pulp types each have unique delay constants.© (2003) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

Laser ablation offers cleaning method for historical and art works effectively. Difference between ablation threshold of contamination layer and the surface yields to remove contaminants from surface without detriment to historical material. In particular, lasers with ultrashort pulse duration are very convenient for brittle historical papers, fibers of which should be intact after cleaning treatment. Since duration of laser irradiation and material interaction is very short, the possibility of damage to the paper is very low. One of the other crucial issues after paper cleaning treatment is color variation on the surface. Authentic color of the historical paper has to be preserved after the procedure. In this paper, we present results of paper cleaning via femtosecond (fs) laser running at a wavelength of 1030 nm. In the first stage of this experimental study, we determined optimum laser parameters on artificially soiled and aged paper samples, then cleaned a handwritten manuscript with ‘sizing’. In calligraphy, ornamentation and miniature arts, sizing is applied on paper as a protective layer which increases strength of paper and renders it more useful. Papers with sizing have been prevalently used in Islamic or Ottoman culture. We observed that after laser irradiation, artificial soling layer is effectively removed, while original color of the subs-layers did not alter. We used scanning electron microscopy (SEM) to examine fiber integrity, and determined that the sizing layer was not removed when optimized parameters were used, thus the fibers were not damaged.

Plastic passive matrix (PM) and active matrix (AM) electronic paper displays (EPDs) have been prepared by SiPix's Microcup® roll-to-roll manufacturing processes using ITO/PET films. The Microcup® displays have shown outstanding environmental stability and excellent physico-mechanical properties such as scratch, impact and flexure resistances even in high temperature and humidity conditions. A PMEPD recently prepared on inexpensive row-and-column patterned ITO/PET films has shown a contrast ratio of >10, ta n 15 V. More than 8 levels of grayscale with outstanding bistability have been demonstrated by either pulse width or pulse count modulation. No noticeable degradation of the mid-tone images has been observed even after the power was turned off for more than 5 days. Moreover, the electro-optical responses, particularly the threshold voltage and gamma of the PMEPDs remain essentially the same within a wide range (20-60°C) of operation temperature.

This work addresses the study of repeatability of an optical laser system, previously implemented by our research team, for characterization of the fiber distribution and mass density of two paper samples with different characteristics. In the experiment that has been carried out in the current work, both paper samples were laser scanned by the system on a total of 16 times (4 times per day in 4 different days). The data acquired and registered during the experimental work, associated to both tested samples, were then processed and the obtained results showed that the optical system is precise.

IR monitoring is a basic tool for quality control and predictive maintenance in the paper industry. There are also other possible interests, e.g. measurements of temperature profiles of high speed production lines. The first possibility to use IR for the above mentioned use appears to be applications of glass heat treatment in on line production. At this time there is a lot of interest to be able to measure temperature profiles from a fast moving surface (e.g. in paper machines) with velocities like 10 - 20 m/s. Normal low speed line scanners typically give scanning speed of 50 Hz which in this case means 20 m/s/50 Hz equals 40 cm resolution. The obtained resolution is not normally high enough. To have more accurate vision from the studied surface IR camera line scanning was proposed to be a solution with line scanning frequencies of 8000 Hz which would provide resolution of 20 m/s/8000 Hz equals 0.25 cm between surface points. It is a well-known fact that all undesired frequencies in paper transfer systems disturb the uniform paper drying process which in some cases is the basic reason for low quality coating or even broken paper line. The possibility to detect these drying problems with IR frequency analysis will give a new way to control the paper drying process. With IR analysis it is possible to get information about temperature distributions along the paper track. Using a well established frequency analysis as a tool, the error estimations are obtained. In most cases an open-roll image from paper track is very desirable because there are no existing wide area measurement systems for this purpose. The careful analysis of this new method is given in the manuscript.© (1996) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

The expression 'Plain' paper was coined in the early days of electrophotography to distinguish the capabilities of the new dry toner based photocopying process which did not require a sensitized or special coated paper to produce an image. Currently 'Plain' paper is considered in the electronic printing industry, to be any uncoated paper, usually of the type used in office photocopying applications. It is assumed that all 'Plain' papers are identical or at least equivalent in their properties such that all papers will give equivalent print quality performance. Due to the wide availability and low price of 'Plain' papers, it is also considered desirable by vendors of electronic marking processes, that their technology be capable of producing good image quality on 'Plain' paper. The chemical and physical differences which can occur among 'Plain' papers are discussed with respect to the specific image quality and engine reliability requirements of the major nonimpact electronic marking technologies, including electrophotography and laser printing, electrographic and ionographic processes, thermal transfer and ink jet. Paper properties of interest include, smoothness, surface energy, electrical resistivity, porosity and aqueous and nonaqueous liquid adsorption. Color printing has added additional requirements to paper quality, if good image quality is to be achieved and maintained. Given the apparently conflicting requirements for some of the electronic marking technologies, it will be a challenge to define a single grade of paper which will produce optimum print quality for all electronic printing processes.© (1995) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

Paper based composite with semiconductor nanomaterial is a fascinating orgnic-inorganic hybrid composite that has improved properties of flexibility, biocompatibility and functionality. Cellulose Electro-Active Paper (EAPap) is a kind of paper electric device. To improve functionality of EAPap, ZnO is used as hybrid inorganic composition. Cellulose- ZnO hybrid nanocomposite (CEZOHN) is fabricated by seeding and growing ZnO on cellulose film with a simple chemical reaction. CEZOHN reveals not only electrical, eletromechanical behavior but also photoelectrical behavior. This paper reports specially photo-response and sensitivity of CEZOHN under several light source: UV light, sun and fluorescent light. The fabrication process is briefly introduced, and induced voltage, induced current under light source are investigated. Also, the ZnO effect of CEZOHN and its mechanism is studied and its possibility of application as photosensor, photodiode, photovoltaic device will be discussed.

There are several parameters, which influence the characteristics of the final printed colors in digital printing. One of the most important one is the substrate (paper). In the present study, the effect of uncoated papers on the laser printed colors was investigated. For this purpose, three kinds of paper with the same grammage value of 80 and different whiteness and texture were selected. The effect of paper on the printer's reproducibility, light-fastness, color gamut and colorimetric characteristics of the final printed samples were studied for a Canon Laser Printer LBP-5050. It was found out that, the reproducibility of the printer is statistically dependent on the paper's type. The average of color change via exposing light is between 1.3 and 1.8 for different papers. The color difference caused by paper variation illustrates the effect of paper on the final printed colors. The texture properties of the papers were quantified with Edge Frequency technique as an appropriate texture analysis tool. A defined correlation between texture changes and color differences was obtained. Furthermore, the whiteness of the papers clearly affected the final printed colors.

Lateral flow tests (LFTs) are well-suited for rapid point-of-care testing in low resource settings. The wicking action of the paper strip moves the sample and reagents through the device without a need for pumps, but LFTs are typically limited to tests that can be carried out in a single fluidic step. The materials from LFTs can be reconfigured to create paper networks that automatically carry out multi-step fluidic operations, while retaining the same easy-to-use format as a conventional LFT. Here, we describe basic principles of wicking and system-level behavior of paper networks by analogy to electrical circuits. We describe key design principles for a previously-developed 2D paper network (2DPN) and introduce an alternative linear paper network (Pseudo-1DPN) that takes advantage of system-level behavior to perform clean sequential fluid delivery while reducing device running time.

This paper reports a remotely-driven electro-active paper (EAPap) actuator by modulated microwaves. So far we have demonstrated a remotely driven EAPap actuator by means of rectenna and control circuit. The rectenna consists of dipole antenna and rectifying circuit, which converts microwave to dc power. Once microwaves are incident on the dipole rectenna, it converts microwaves into a dc power and the control circuit feeds the power to the EAPap actuator by alternating it so as to produce a bending motion of the EAPap actuator. However, due to the power consumption of the control circuit, the remotely-driven actuator system requires more dc power to activate the control circuit. Thus, we propose a remotely-driven EAPap actuator that does not require the control circuit. Instead of the control circuit, microwaves are modulated with the control signal, and by rectifying the modulated microwaves with the rectenna, the control signal can be regenerated for activating the EAPap actuator. Detailed modulated microwave, rectenna design, fabrication, characterization and the actuation of rectenna-EAPap by modulated microwave are explained.

Lasers can provide a precious tool to conservation process due to their accuracy and the controlled energy they deliver, especially to fragile organic material such as paper. The current study concerns laser modification such as paper cleaning, initially of test papers artificially soiled and then of an original book of the early 20 th Century. The test objects were A4 copier paper, newspaper, and paper Whatman No.1056. During the experiments, ink of a pen, pencil and ink from a stamp was mechanically employed on each paper surface. Laser cleaning was applied using a Q-switched Nd:YAG operating at 532 nm and CO 2 laser at 10.6 μm for various fluences. The experimental results were presented by using optical microscopy. Eventually, laser cleaning of ink was performed to a book of 1934, by choosing the best conditions and parameters from cleaning the test samples, like Nd:YAG laser operating at 532 nm.

Strong demand exists for a non-contacting paper caliper measurement which can be used as an input to a paper thickness control system. Caliper sensors requiring sheet contact suffer from errors related to dirt or coating build up and from high maintenance costs related to wear. These sensors can also damage the product by picking holes and marking sheets. Details of an on-line measurement device which employs two opposed laser displacement sensors and an inductive displacement sensor are presented. The sheet is held perpendicularly to the sensors with a Coanda air clamp. Dust and temperature control features which enable the sensor to operate reliably in an industrial environment are discussed. Results of production trials of this sensor are presented. Sub-micron profile agreement to lab and contacting caliper measurements has been demonstrated on light sheets. Results are presented of measurements on a wide range of paper grades from coated and uncoated light sheets to coated board.

Online measurement of paper thickness profile is essential in paper production. For decades paper thickness has been measured online with sensors that are contacting the web on both sides. In 2005 a new optical online paper thickness gauge was introduced which only contacts the web on the other side. The sensor is based on a laser triangulation sensor and a magnetic sensor, and it determines the paper thickness from the difference of the two measurements. For calibration of the two sensors, a robust concept has been developed which utilizes the measured object and takes place in the measuring environment so that the calibration is automatically adjusted to the current measuring circumstances. More importantly, with the presented method the non-linearity of the laser sensor is cancelled enabling the measurement of the thickness profile shape with an accuracy much better than that of the laser sensor. Profile accuracy of 0.5 μm (2σ) has become normal while the measuring range is often several hundreds of microns and the measuring distance to the paper web 1.0-1.5 mm with a laser sensor having linearity of ±2 μm.

In this paper we report the use of a sheet of cellulose fiber-based paper as the dielectric layer used in oxide based semiconductor thin film field-effect transistors (FETs). In this new approach we are using the cellulose fiber-based paper in an "interstrate" structure since the device is build on both sides of the cellulose sheet. Such hybrid FETs present excellent operating characteristics such as high channel saturation mobility (>30 cm 2 /Vs), drain-source current on/off modulation ratio of approximately 10 4 , near-zero threshold voltage, enhancement n-type operation and sub-threshold gate voltage swing of 0.8 V/decade. The cellulose fiber-based paper FETs characteristics have been measured in air ambient conditions and present good stability. The obtained results outpace those of amorphous Si TFTs and rival with the same oxide based TFTs produced on either glass or crystalline silicon substrates. The compatibility of these devices with large-scale/large-area deposition techniques and low cost substrates as well as their very low operating bias delineates this as a promising approach to attain high-performance disposable electronics like paper displays, smart labels, smart packaging, RFID and point-of-care systems for self analysis in bio-applications, among others.

Quantitative analysis of pH indicator paper color is needed in the various fields. An indigenously developed Tristimulus colorimeter is used in this work for pH Indicator paper color measurement. The colorimeter uses Trichromatic RGB LEDs and a programmable color light to frequency converter (TCS230), combining configurable silicon photodiodes and a current to frequency converter on a single monolithic CMOS integrated circuit. The output is a square wave (50% duty cycle) with frequency directly proportional to light intensity. Digital input and digital output allow directly to a microcontroller. The light to frequency converter reads an 8*8 array of photodiodes. Sixteen photodiodes have red filters, 16 photodiodes have green filters, 16 photodiodes have blue filters, and 16 photodiodes are clear with no filters. All 16 photodiodes of the same colors are connected in parallel and type of photodiode the device uses during operation is pin selectable. Solutions having different standard pH were prepared and indicator paper was dipped in solution, it shows change in color. Using the developed RGB colorimeter chromaticity coordinates were measured and compared with the chromaticity coordinates measured using Ocean Optics HR-4000 high resolution spectrophotometer.

Two different paper grades were tested with a clearing agent to measure how much mechanical smoothening can improve transparency inside paper. The paper grades were newsprint and supercalendered paper. The paper furnishes of both papers were alike, but the supercalendered paper was mechanically smoothened. Anise oil was used as the clearing agent, but similar measurements were also done with air and water. Black lines 8.5 μm to 281.1 μm wide were placed behind layers of cleared paper and transparency was measured with a microscope. When anise oil was the clearing agent, supercalendering improved transparent paper grammage from 139 g/m 2 to 164 g/m 2 . With water the improvement was from 40 g/m 2 to 51 g/m 2 . With air the improvement was not determinable. As a conclusion, it is recommended that paper is smoothened if it needs to be studied optically. Optical coherence tomography, for example, would benefit from this treatment.

Common experience indicates the quality of a printed image depends on the choice of the paper used in the printing process. In the current report, we have used a recently developed device called a micro-goniophotometer to examine toner on a variety of substrates fused to varying degrees. The results indicate that the relationship between the printed color gamut and the topography of the substrate paper is a simple one for a color electrophotographic process. If the toner is fused completely to an equilibrium state with the substrate paper, then the toner conforms to the overall topographic features of the substrate. For rougher papers, the steeper topographic features are smoothed out by the toner. The maximum achievable color gamut is limited by the topographic smoothness of the resulting fused surface. Of course, achieving a fully fused surface at a competitive printing rate with a minimum of power consumption is not always feasible. However, the only significant factor found to limit the maximum state of fusing and the ultimate achievable color gamut is the smoothness of the paper.

The propagation of broadband ultrasonic pulses in combined media that consist of printing paper of different porosity saturated with different liquids is studied. The experiments are performed with three types of paper, namely, Zoom Ultra (Stora Enso, Finland) with surface densities of 80 and 100 g/m2 and Data Copy (Mo Do, Sweden) with a surface density of 160 g/cm2, and with two types of saturating liquids: ethanol and transformer oil. To excite ultrasonic pulses and to detect them with a high time resolution, the laser optoacoustic spectroscopy method is used. For each type of liquid-saturated paper, the phase velocity of ultrasound is measured in the frequency range of 5–35 MHz. The absence of any noticeable frequency dispersion of the phase velocity is revealed. The possibility of measuring the porosity of printing paper on the basis of the theoretical model of a two-phase medium with the use of the corresponding experimental data is demonstrated.

This study is focused on laser structuring processes for producing secure tactile features on paper-based security documents. The feasibility of using the developed technique allows users and/or machines to discriminate among genuine and counterfeited security documents and/or facilitate the tactile detection by visually impaired people.

The size distribution and total amount of the particles in paper pulp is vital information for the paper manufacturer in optimising process control and maintaining a high product quality. There is a further need for improving the on-line measurement methods to measure these parameters. It is known that fibre and fines fractions in the pulp have different optical and acoustic properties. In this study, we simultaneously use laser radar and laser generation of acoustic waves to further study optical and acoustic parameters, such as optical time delay, acoustic speed and attenuation. A near infrared pulse laser is used to illuminate the pulp suspensions and the time-of-flight of scattering photons is recorded; and at the same time, a high energy pulsed laser is applied to produce an acoustic wave. The acoustic wave propagates through the pulp suspensions and an acoustic transducer is used to detect the signals from which the attenuation and acoustic speed are determined. The results show that these combined optical techniques can potentially determine the content of fibres and fine particles simultaneously.

In 1905 Karl Schwarzschild published three papers on optics, two of which revolutionized the field of reflecting telescope optics. In his first paper he developed a full theory of the aberrations of reflecting telescopes, generalizing the Eikonal of Bruns to take into account systems with an infinite long conjugate. In the second paper Schwarzschild applied his formulation to a masterful analysis of 2 mirror anastigmatic systems, along the way discovering the so called Ritchey-Chretien aplanat, 18 years Ritchey and Chretien's announcement. Numerous other innovations are given in what must be seen as being among the most important papers on the aberrations of optical systems ever written.

This paper presents the design and development of a safe MEMS based micro electro-thermal igniter for a safe microfuze for military purpose. The proposed device"s architecture is made of: (1) one pyrotechnical micro igniter, (2) one arming function, (3) one disarming function and (3) one sterilization function. The pyrotechnical electro-thermal igniter consists in a resistive element that converts electrical energy into heat to initiate an energetic material. The arming function permits the igniter to be armed, ready to fire, only if the ignition conditions are respected. For that, a short-circuit to the electrical ground is cut and the igniter is connected to the power supply. The igniter can be reset to the safe mode (disarmed state) thanks to the disarming function that reconnects the igniter's electrical pads to the electrical ground. If necessary the igniter can be sterilized meaning that the system's ignition capability is definitively removed. All these functions are based on the use of two electro-thermal micro switches : one ON-OFF and one OFF-ON. Due to the application requirements (the fuze is used once but after a long storage, all components must have a high level of safety and reliability and the power consumption must be minimized), we opted for a new generation of one shot, safe and reliable micro switches. They are based on electro thermal mechanisms and consist in breaking one electrical connection (ON-OFF switch) or micro soldering locally two electrical connections (OFF-ON switch). Both switches have been developed in MEMS technology, characterized and are presented in this paper. A prototype of safe micro igniter with ON-OFF and OFF-ON switches has been also realized and is presented.© (2005) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

This paper reviews state of the art mask modeling for optical lithography. Rigorous electromagnetic field (EMF) simulation of light diffraction from optical masks is compared to the traditional assumption of an infinitely thin mask, the so called Kirchhoff approach. Rigorous EMF simulation will be employed to analyze mask polarization phenomena which become important in the ultrahigh NA regime. Several important lithographic phenomena, which can be explained only with rigorous EMF simulation, are discussed. This includes the printability of small assist features, intensity imbalancing for alternating PSM, and process window deformations. The paper concludes with a discussion on material issues and algorithmic extensions which will be necessary for an accurate modeling of future mask technology.

A non-contacting online caliper measurement has been papermakers' dream for over two decades. Currently, paper thickness is measured using buttons contacting the paper web on both sides. In such a configuration, paper thickness is assumed to be the distance between the contacting surfaces and determined by a magnetic measurement principle. However, this arrangement of contacting measurement has several disadvantages including sheet marking, hole creation, dirt build-up on the contacting buttons, wearing of the contacting surfaces, and even sheet breaks. Moreover, the current trends in paper manufacturing, especially the increasing use of recycled raw materials are necessitating the development of a more reliable thickness measurement solution that is not affected by dirt and other material on paper or board sheet surfaces. So far, a non-destructive, on-line thickness measurement has not been successfully applied in paper production environment. Recently, Metso Automation has successfully piloted in several mills a caliper sensor that does not contact the sheet on both sides and is able to measure paper thickness with sub-micron accuracy. The new sensor is based on single sided laser triangulation. This paper presents the measurement set-up and discusses the challenges encountered. Measurement results obtained in mill trials with various paper grades are reviewed and compared to those made simultaneously with contacting, on-line sensors and off-line laboratory results of the same sheet. Factors affecting the measurement with conventional and optical thickness sensors are also discussed.

High-resolving full-field OCT method is considered that provides increased resolution and interferometric data acquisition speed due to high optical magnification and electronic lateral scan provided by video camera. OCT data processing algorithm based on signal squaring with subsequent low-pass filtering is considered. Experimental results obtained when evaluating samples of paper material are presented and discussed.

We design the emission and detection optical paths of three monochromatic infrared light sources with different wavelength. The three light sources are placed according to the different angles, so that the three kinds of monochromatic lights are converged on the same point of the sample. Using the method, we can detect the same point and improve the measurement accuracy. We choose the standard near-infrared monochromatic light source, so that we can save some equipments, such as tungsten- halogen lamp, filtered wheel, collimation focalizer, electric machine, and so on. In particular, we save the cumbersome cooling system, reduce the volume of the instrument greatly and reduce the cost. The three monochromatic light sources are supplied by the same pulse power source, to ensure their synchronous working.

Electro-Active Paper (EAPap) is attractive for EAP actuator due to its merits in terms of lightweight, dry condition, large displacement output, low actuation voltage and low power consumption. A promising EAPap actuator has been developed using cellulose paper. It is necessary to investigate the environmental factors for many applications. The performance variation along with the temperature and humidity is investigated. Tip displacement is measured by laser sensor and the power consumption of EAPap is investigated. When 0.3kV/mm of excitation voltage is applied, more than 4mm of tip displacement is obtained out of 40mm long EAPap sample. Since the power requirement of EAPap is so small(8.8mW/cm 2 ), it can be activated by remote microwave power, which is promising for many applications

The construction of electromechanical actuator has been achieved by using the conducting polypyrrole films deposition onto a gold-coated cellophane paper. This is probably the first report of this type of paper actuator. The conducting polypyrrole was electro-generated using either galvanostatic or potentiostatic conditions at 0.5 mA/cm2 current density or 0.7 volts applied potential. The two types of actuators were constructed namely: 1.Ppy/Cellophane bilayer 2. Ppy/ Cellophane paper /Ppy trilayer using electrochemical technique. These actuators showed a reversible and reproducible displacement in acetonitrile solution containing LiClO4 (1M). The maximum displacement of 9.1 mm was recorded for tri-layer device and 3.5 mm for bi-layer device in 1M LiClO4 acetonitrile solutions. The prepared actuator devices were investigated for their mechanical actuation in air medium. The actuation in air is comparatively less than in solution actuation, but still it showed significant movement in air also. The results obtained in acetonitrile solution containing 1M LiClO4 shows that the actuator requires very low excitation voltages of 0.2 MV m-1 at 0.5 Hz frequencies. The effect of humidity on the actuation properties was addressed. The humidity measurement was carried out between 60% to 95% humidity with the help of humidity-temperature controlled chamber. The resonating frequency of 3 Hz at 6 volts had shown 1.8 mm displacement at 95% humidity for gold-coated cellophane sample without polypyrrole.

In this study, we propose to apply the method optical coherence tomography (OCT) for paper characterization. A PC-controlled experimental measurement system for OCT-imaging of paper is described in detail. A superluminescent diode is used as a light source in a Michelson interferometer. A rapid scanning optical delay line is using a piezo-transducer to modulate the measurement signal for optical heterodyne detection. Amplification, filtering and demodulation are performed by the unit specially designed for this purpose. Experimental measurements include the OCT slice imaging of a paper sample and comparison with a SEM-image. Also some results in surface profilometry are presented briefly. Discussion part gives some ideas of further research that will be carried out in the future.© (2004) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

The effect of a Q-switched Nd:YAG laser irradiation applied for ablative cleaning of the surface contaminants on cellulose samples and aimed on conservation of historical paper documents is investigated. The removal effectiveness of an artificial graphite contamination from model samples is investigated in dependence on the laser wavelength (532, 355 and 266 nm) and fluence (0.3 to 0.9J/cm 2 ) and also the surface color changes are measured. Damages of cellulose fibers due to laser interaction are examined by means of the SEM technique. For irradiation at 266 nm only partial removal of the contamination and a distinct cellulose degradation, and also the yellowing of paper surface are observed. For the 355 nm wavelength and energy fluence below 0.6 J/cm 2 the degradation of cellulose fibers does not occur. However, a slight yellowness of the surface is observed. The optimal cleaning wavelength of 532 nm and safe energy fluence below 0.6 J/cm 2 found experimentally agree with literature.

Results of paper cleaning by means of the 532 nm Nd:YAG laser (pulse length 6 ns, fluency 0.3-0.6 J/cm2) are reported and discussed. Results of the surface cleaning of the paper samples originating among others from the two oldest Polish Bibles (XVI c.) are examined by the SEM technique after laser processing. For the process diagnostic the LIF spectra of paper samples recorded under excitation at 266 nm and 532 nm before and after processing are analysed and spectra of the non-contaminated samples are taken for reference. The presence of contamination and also cleaning history is evidenced in the recorded spectra. Comparison of SEM images and also the spectral characteristics of the originally contaminated samples before and after laser treatment confirm results of the laser cleaning.

A device has been designed for off-line optical paper inspection and quality control of stripes and holes in the cigarette paper. Hardware description is first presented including main paper characteristics to be measured. Typical paper stripe and holes structures are then discussed with image processing and analysis considerations to discriminate these structures, focusing in the problems derived from the small area of holes and of their internal structure that is analyzed with a confocal microscope. Algorithms for image processing and analysis are described. These algorithms involve equalization, binarization, stripes structure detection, holes distribution and statistics.

In this paper we give an overview on NTera's novel reflective display technology with real 'ink-on-paper' readability. Our technology is based on mesoporous wide-bandgap semiconductor films modified with self-assembled monolayers of electrochromic chromophores. The direct vicinity of each electrochromophore to the semiconductor allows its electronic addressing in the millisecond domain. The high molar extinction coefficient of the organic chromophores in conjunction with the extremely large specific surface area of the mesoporous semiconductor substrate allows to achieve deep colorations with high contrast ratios. Combined with a unique white reflector technology yielding reflectivities above 50 percent and excellent angular contrast independnece, oru displays show outstanding optical properties, comparable to those of ink on paper. Applying simple printing techniques these displays can be manufactured from commercially available nanomaterials like TiO 2 or other doped or undoped metal oxides. Along with favorable electronic properties like low power consumption and excellent open-circuit memory electrochromic displays seriously rival conventional LCD display applications.

This paper gives a comprehensive and up-to-date review of our research activity on MEMS (micro electro mechanical systems) for all- optical fiber optic communications. Micromechanical approach for handling optical signal has advantages over solid-state devices in terms of high contrast intensity modulation by relatively large change of refractive index, large spatial scan angle by optomechanical reflection or refraction, and optical transparency in wide range of wavelength. MEMS also has industrial impact in a sense that it could potentially eliminate or cut down the cost of optical assembly thanks to the optical pre-aligning or self-aligning capability. In particular, we take an example of MEMS variable optical attenuator (VOA) that we have commercially released in cooperation with an industrial partner. Besides fiber optic MEMS, we also mention other applications such as projection displays using a high-speed MEMS optical scanner for scanning modulated laser beam to create images. Furthermore, we also introduce a MEMS color pixel based upon the mechanically tunable Fabry-Perot interferometer made of two plastic films; the color pixel can be assembled in an array format to create a transparent-type over-sized electronic poster which is mechanically flexible and electrically rewritable.

The ongoing Chinese ever-ambitious project of Large Sky Area Multi-Object Fiber Spectroscopic Telescope (LAMOST) has brought about a tremendous challenge for the control engineers. To the bottom line the giant 4-meter class ground telescope is a comprehensive optomechatronic platform to achieve high performance and functionality, such as its capability of observing 4000 stars simultaneously, which will set a world record in contemporary ground survey telescopes. This paper outlines the R&D stages of the control system for the project along with its integrated strategy of optomechatronic components in general and network control framework in particular. The approach is to make a careful investigation with respect to the time crucialness for execution of different tasks so as to utilize different networks. However, the overall network framework is based on a distributed platform, hierarchical structure and open architecture to boost the flexibility. Vigorous study has been invested and a number of cutting edge techniques have been applied to meet the tough network control requirements, such as real-time database, powerful interfaces, sophisticated controllers, remote control, etc.

In this letter, we proposed a simple and cost-effective variable optical attenuator (VOA) through controlling a mechanical misalignment between 2 single mode fibers. A piezoelectric ceramic tube having 4 electrodes on the surface is the key component in our proposed structure. We can change the deflection of the tube by controlling the applied voltage on the electrodes of the tube, which causes the optical loss to be dependent on the applied voltage. The fact that the piezoelectric ceramic tube can be easily fabricated by using the electro-phoretic deposition processing makes our structure more attractive for mass production. The tube-fabrication processing is out of the range in this paper. So, the detail technical approach of the tube fabrication is excluded intentionally. The numerical analysis about the optical loss related to the various mechanical offsets is also investigated. From our experimental results, the dynamic range of the proposed structure is about from 0 to 25 dB when the applied voltage range is from 0 to 600 V DC. Our proposed structure can be a good candidate for a simple and cost-effective variable optical attenuator in optical communication system field.

In phase-shifting digital holographic interferometry for measuring a displacement distribution of an object, holograms and reconstructed images have speckle noise and they provide large error in the calculation of displacement analysis. In order to decrease the effect of speckle noise, we previously proposed a new method using windowed holograms. In this paper, we propose a new averaging method of the obtained phase-difference values. Many phase-difference values at a point obtained by different windows for a hologram are averaged by considering the weight for each phase value. The weight is changed as the m-th power of the absolute amplitude of the complex amplitude of the reconstructed object. As the result, when the number n of the windowed holograms becomes larger, the standard deviation of the error becomes smaller. When the power m is 2, the error becomes the minimum. The standard deviation of the errors in the case of a flat plate with 316 nano-meter out-of-plane displacement is 88 pico-meter when n=1024 and m=2.

In this paper we review the fabrication and characterisation techniques of m icrostructured optical fibre (M OF) tapers, their fundam ental waveguiding properties and potential applications. W e fabricate photonic crystal fibre tapers without collapsing the air-holes, and confirm this along the taper with a non-invasive probing technique. We then describe the fundam ental property of such tapers associated with the leakage of the core m ode that leads to long wavelength loss. We also revisit the waveguiding properties in another form of tapered MOF photonic wires, which transition through waveguiding regimes associated with how strongly the mode is isolated from the external environment. We explore these regimes as a potential basis for evanescent field sensing applications, in which we can take advantage of controlled airhole collapse as an extra dimension to these photonic wires.

The emergence of vertical cavity surface emitting laser (VCSEL) and photo diode (PD) arrays has given scope for the development of many applications such as high speed data communication. Further increase in performance can be obtained by the inclusion of micro-mirrors and microlens in the optical path between these components. However, the lack of efficient assembly and alignment techniques has become bottlenecks for new products. In this paper, we present development of optical sub-assembly and metallic MEMS structures that enable in the massively parallel assembly and alignment of these components to form a single miniature package. VCSEL wafer was processed to have polymer pedestal and polymeric lens on top of it. Such optical sub assembly greatly increases coupling efficiency between the VCSEL and optical fibers. Multiple numbers of suspended MEMS serpentine springs made out of electroplated nickel have been fabricated on ceramic substrates. These springs serve for clamping and alignment of multiple numbers of optoelectronic components. They are designed to be self-aligning with alignment accuracies of less than 3 micron after final assembly. Electrical connection between the bond pads of VCSEL's and PD's to the electrical leads on the substrate has been demonstrated by molten solder inkjet printing into precisely designed MEMS mold structures. This novel massively parallel assembly process is substrate independent and relatively simple process. This technique will provide reliable assembly of optoelectronic components and miniature optical systems in low cost mass production manner.

Semiconductor devices are making important role in our life. Many semiconductor chips will be used to every thing, and we will receive the various services anywhere anytime through a digital network. There are so many applications using semiconductor products that support such a ubiquitous era, and it is expected that mobile, automobile and PC/AV applications will have the great growth from now on. In this paper, we describe the lithography technology trend and requirements for mask technology from the view point of SOC and FLASH memory trend. From the device development trend, it is expected that FLASH memory become driving force of lithography technology. To realize hp45nm node and beyond, the installation of hyper-NA ArF-immersion tools with low-k1 technique is the key issue. With this, DFM (Design For Manufacturability) is the key technology and a continuous approach of systematic DFM technique is important in order to reduce chip cost. Also, Mask DFM is needed to realize cost-effective low-k1 process and it drives reasonable mask cost and TAT. In order to reduce mask cost in device development and small volume production, we expect greatly that maskless lithography (ML2) become a leading tool in lithography.

Optical methods continue to play significant roles in medical and biological research. In recent times cell and tissue engineering have emerged rapidly and are now well recognised as important multi-disciplinary endeavours within the medical and biological spheres. This paper describes applications of optical science and technology in cell and tissue engineering, ranging from the basic visualization of organeeles, cells and tissues through to probing the structure and function of cells and tissues being cultured in bioreactors. The development of tissue engineering for the fabrication of cell-based systems, for example for the repair or replacement of damaged or diseased tissues and organs, is first described. Then, interactions of light propagating through cells and tissues are considered, both theoretically and practically, as a prelude to the description of means for optical interrogation. Scattering and absorption of light by cells and tissues is shown to provide useful opportunities for measurement, for example via spectrophotometric analysis or small angle light scattering. Optical sensors for chemical analysis based on immobilised fluorophores and chromophores are also presented, these being particularly useful in bioreactors. In this application the continuous monitoring of a variety of chemical and physical variables may lead to optimised cell and tissue culture.