Showing papers by "Philips published in 1998"

Synthesis and Growth of ZnO Nanoparticles

Abstract: ZnO nanoparticles in the size range from 2 to 7 nm were prepared by addition of LiOH to an ethanolic zinc acetate solution. This method [Spanhel, L.; Anderson, M. A. J. Am. Chem. Soc. 1991, 113, 2826] was modified and extended at several points. The synthesis of very small ZnO nuclei was simplified. It was found that aging of particles was governed by temperature, the water content, and the presence of reaction products. Water and acetate induced considerably accelerated particle growth. Growth could almost be stopped by removal of these species (“washing”). Washing consisted of repeated precipitation of ZnO by addition of alkanes such as heptane, removal of the supernatant, and redispersion in ethanol. The aging characteristics are interpreted in terms of the concentration of dissolved ZnII species and reactions well-known in sol−gel chemistry. These findings present a better-defined and more versatile procedure for production of clean ZnO sols of readily adjustable particle size. Such sols are of partic...

New Developments in the Field of Luminescent Materials for Lighting and Displays

Abstract: Owing to their use in fluorescent lamps and many display applications, luminescent materials affect our daily life. Improvement of already very mature as well as development of new materials demanded by a variety of new applications are the focus of research today. The latest advances in the field of electroluminescence enable new displays and light generation concepts that challenge the classical areas of application of luminescent materials.

Multicolored led lighting method and apparatus

Abstract: The systems and methods described herein relate to LED systems capable of generating light, such as for illumination or display purposes. The light-emitting LEDs may be controlled by a processor to alter the brightness and/or color of the generated light, e.g., by using pulse-width modulated signals. Thus, the resulting illumination may be controlled by a computer program to provide complex, predesigned patterns of light in virtually any environment.

Theory of the field-effect mobility in amorphous organic transistors

Abstract: The field-effect mobility in an organic thin-film transistor is studied theoretically. From a percolation model of hopping between localized states and a transistor model an analytic expression for the field-effect mobility is obtained. The theory is applied to describe the experiments by Brown et al. [Synth. Met. 88, 37 (1997)] on solution-processed amorphous organic transistors, made from a polymer (polythienylene vinylene) and from a small molecule (pentacene). Good agreement is obtained, with respect to both the gate voltage and the temperature dependence of the mobility.

The checkpoint protein MAD2 and the mitotic regulator CDC20 form a ternary complex with the anaphase-promoting complex to control anaphase initiation

Abstract: The spindle assembly checkpoint mechanism delays anaphase initiation until all chromosomes are aligned at the metaphase plate. Activation of the anaphase-promoting complex (APC) by binding of CDC20 and CDH1 is required for exit from mitosis, and APC has been implicated as a target for the checkpoint intervention. We show that the human checkpoint protein hMAD2 prevents activation of APC by forming a hMAD2-CDC20-APC complex. When injected into Xenopus embryos, hMAD2 arrests cells at mitosis with an inactive APC. The recombinant hMAD2 protein exists in two-folded states: a tetramer and a monomer. Both the tetramer and the monomer bind to CDC20, but only the tetramer inhibits activation of APC and blocks cell cycle progression. Thus, hMAD2 binding is not sufficient for inhibition, and a change in hMAD2 structure may play a role in transducing the checkpoint signal. There are at least three different forms of mitotic APC that can be detected in vivo: an inactive hMAD2-CDC20-APC ternary complex present at metaphase, a CDC20-APC binary complex active in degrading specific substrates at anaphase, and a CDH1-APC complex active later in mitosis and in G1. We conclude that the checkpoint-mediated cell cycle arrest involves hMAD2 receiving an upstream signal to inhibit activation of APC.

Uv/blue led-phosphor device with efficient conversion of uv/blue light to visible light

Abstract: A light emitting device for use in lighting and/or display applications includes a UV/blue LED located in a depression having reflecting sidewalls, a light transmitting material surrounding the LED and filling the depression, and a phosphor in the form of particles either dispersed in the light transmitting material or adhered to the surface of the LED. The sidewalls reflect UV as visible light, thus enhancing the efficiency of the device. Optical filters located on the top of the LED and/or the bottom of a UV absorbing glass plate covering the depression further enhance efficiency and/or spectral characteristics of the emitted light.

Testing embedded-core based system chips

Abstract: Advances in semiconductor process and design technology enable the design of complex system chips. Traditional IC design in which every circuit is designed from scratch and reuse is limited to standard-cell libraries, is more and more replaced by a design style based on embedding large reusable modules, the so-called cores. This core-based design poses a series of new challenges, especially in the domains of manufacturing test and design validation and debug. This paper provides an overview of current industrial practices as well as academic research in these areas. We also discuss industry-wide efforts by VSIA and IEEE P1500 and describe the challenges for future research.

Seed size, shape and vertical distribution in the soil: Indicators of seed longevity

Abstract: 1. We investigated the vertical distribution of seeds in the soil, using data from nine studies in five European countries. We discovered significant correlations between seed shape and distributio ...

Web-based, biometric authentication system and method

Abstract: A Web-based authentication system and method, the system comprising at least one Web client station, at least one Web server station and an authentication center. The Web client station is linked to a Web cloud, and provides selected biometric data of an individual who is using the Web client station. The Web server station is also linked to the Web cloud. The authentication center is linked to at least one of the Web client and Web server stations so as to receive the biometric data. The authentication center, having records of one or more enrolled individuals, provides for comparison of the provided data with selected records. The method comprises the steps of (i) establishing parameters associated with selected biometric characteristics to be used in authentication; (ii) acquiring, at the Web client station, biometric data in accordance with the parameters; (iii) receiving, at an authentication center, a message that includes biometric data; (iv) selecting, at the authentication center, one or more records from among records associated with one or more enrolled individuals; and (v) comparing the received data with selected records. The comparisons of the system and method are to determine whether the so-compared live data sufficiently matches the selected records so as to authenticate the individual seeking access of the Web server station, which access is typically to information, services and other resources provided by one or more application servers associated with the Web server station.

Modeling statistical dopant fluctuations in MOS transistors

Abstract: The impact of statistical dopant fluctuations on the threshold voltage V/sub T/ and device performance of silicon MOSFET's is investigated by means of analytical and numerical modeling. A new analytical model describing dopant fluctuations in the active device area enables the derivation of the standard deviation, /spl sigma/V/sub T/, of the threshold voltage distribution for arbitrary channel doping profiles. Using the MINIMOS device simulator to extend the analytical approach, it is found that /spl sigma/V/sub T/, can be properly derived from two-dimensional (2-D) or three-dimensional (3-D) simulations using a relatively coarse simulation grid. Evaluating the threshold voltage shift arising from dopant fluctuations, on the other hand, calls for full 3-D simulations with a numerical grid that is sufficiently refined to represent the discrete nature of the dopant distribution. The average V/sub T/-shift is found to be positive for long, narrow devices, and negative for short, wide devices. The fast 2-D MINIMOS modeling of dopant fluctuations enables an extensive statistical analysis of the intrinsic spreading in a large set of compact model parameters for state-of-the-art CMOS technology. It is predicted that V/sub T/-variations due to dopant fluctuations become unacceptably large in CMOS generations of 0.18 /spl mu/m and beyond when the present scaling scenarios are pursued. Parameter variations can be drastically reduced by using alternative device designs with ground-plane channel profiles.

System and method for permitting three-dimensional navigation through a virtual reality environment using camera-based gesture inputs

Abstract: A system and method for permitting three-dimensional navigation through a virtual reality environment using camera-based gesture inputs of a system user. The system comprises a computer-readable memory, a video camera for generating video signals indicative of the gestures of the system user and an interaction area surrounding the system user, and a video image display. The video image display is positioned in front of the system user. The system further comprises a microprocessor for processing the video signals, in accordance with a program stored in the computer-readable memory, to determine the three-dimensional positions of the body and principle body parts of the system user. The microprocessor constructs three-dimensional images of the system user and interaction area on the video image display based upon the three-dimensional positions of the body and principle body parts of the system user. The video image display shows three-dimensional graphical objects within the virtual reality environment, and movement by the system user permits apparent movement of the three-dimensional objects displayed on the video image display so that the system user appears to move throughout the virtual reality environment.

Power/data protocol

Abstract: Provided herein are methods and systems for powering a device, which include providing a data signal and extracting power from the data signal to power the device. The device may be either a device that responds to the data signal or another device. The data signal may vary between at least two data states. The methods and systems may extract power during one or both of the data states. The methods and systems may include a multiplexor. The controlled device may be an RS-485 compliant device, such as an LED system associated with a processor. The data signal may be a DMX-512 signal. The data signal may control a processor for control of the device.

Deinterlacing-an overview

Abstract: The question "to interlace or not to interlace" divides the television and the personal computer communities. A proper answer requires a common understanding of what is possible nowadays in deinterlacing video signals. This paper outlines the most relevant proposals, ranging front simple linear methods to advanced motion-compensated algorithms, and provides a relative performance comparison for 12 of these methods. Next to objective performance indicators, screen photographs have been used to illustrate typical artifacts of individual deinterlacers. The overview provides no final answer in the interlace debate, as such requires unavailable capabilities in balancing technical and nontechnical issues.

Data delivery track

Abstract: Track lighting methods and apparatus. In various examples, power and data are provided to a plurality of lighting fixtures via at least one pair of essentially rigid electrically conductive tracks that are mechanically coupled to an essentially rigid linear or curvilinear-shaped housing. The plurality of lighting fixtures includes at least one LED-based lighting fixture mechanically coupled to the housing, electrically coupled to the at least one pair of electrically conductive tracks, and configured to be responsive to the data.

Remote control device with location dependent interface

Abstract: A user control interface is provided that is location dependent. Context control parameters are associated with location, and the user control interface is customized to the context within which the device is being operated. The control interface includes the presentation of context sensitive information and the communication of corresponding context sensitive user commands via the interface. The location determination is effected using any number of commonly available techniques, such as direct entry, infrared sensors and active badges for relative positioning, as well as the conventional absolute positioning devices such as LORAN and GPS. Preferably, the device communicates with a remote information source that provides the context sensitive control information. The remote information source may be a home network server, an Internet server, a public service network, or other communication network.

Personalizing hospital intranet web sites

Abstract: The server includes a layer for dynamically generating web pages and other data objects using scripts, such as graphic, audio and video files, in dependence on stored information indicating the user's needs and preferences, including those presumed from stored information as to the user's function, job, or purpose for being at the hospital, and logged usage profiles, the level of the user's access privileges to confidential patient information, and the computer and physical environments of the user. Notably, the content is generated in dependence on the display resolution and lowest bandwidth link between the server and browser to limit the waiting time for downloads as well as the server load.

A structured and scalable mechanism for test access to embedded reusable cores

Abstract: The main objective of core-based IC design is improvement of design efficiency and time-to-market. In order to prevent test development from becoming the bottleneck in the entire development trajectory, reuse of pre-computed tests for the reusable pre-designed cores is mandatory. The core user is responsible for translating the test at core level into a test at chip level. A standardized test access mechanism eases this task, therefore contributing to the plug-n-play character of core-based design. This paper presents the concept of a structured test access mechanism for embedded cores. Reusable IP modules are wrapped in a TESTSHELL. Test data access from chip pins to TESTSHELL and vice versa is provided by the TESTRAIL, while the operation of the TESTSHELL is controlled by a dedicated test control mechanism (TCM). Both TESTRAIL as well as TCM are standardized, but open for extensions.

Electronic apparatus comprising fingerprint sensing devices

Abstract: An electronic apparatus comprising a fingerprint sensing device (10) having an array of sensing elements (12) carried on a transparent substrate (35) for sensing capacitively the ridge pattern of a fingerprint placed over the array, in which the transparency of the device is utilised to provide additional capabilities. Thus, an optical sensing device (60) may be disposed beneath the device (10) to sense optically through the device a further biometric characteristic, or the presence, of the finger overlying the sensing element array. Substantial transparency can be afforded to the device by forming the sense electrodes (30) of the array from transparent conductive material. In products like mobile telephones, notebook computers, PDAs, smart cards or like portable electronic products of small size such a fingerprint sensing device can then advantageously be arranged overlying a display device with the display output being visible through the device.

LED luminaire with electronically adjusted color balance

Abstract: A luminaire comprises an array of LEDs that include at least one LED in each of a plurality of colors. Supplied to the LEDs for each color is an electrical current that, during a measuring period, comprises a measuring drive pulse having at least a first boost portion and a turn-off portion. The LEDs relating to each color have a light output which has a nominal continuous value during ordinary operation and increases during the boost portion and is interrupted during the turn-off portion. The array has a combined light output when current is supplied to all of the LEDs in the array. A photodiode is arranged to measure the combined light output which selectively turning off the electrical current to the LEDs so that the photodiode measures the light output for each color separately in response to the measuring drive pulse. The average light output during the measuring period is substantially equal to the nominal continuous light output during the ordinary operation so as to avoid visible flickers.

White light-emitting diode

Abstract: The invention relates to a light-emitting device comprising a UV diode with a primary emission of 300 nm ≤ μ ≤ 370 nm,and a phosphor layer consisting of a combination of a blue-light emitting phosphor with an emission band of 430 nm ≤ μ ≤ 490 nm, a green-light emitting phosphor with an emission band of 520 nm ≤ μ ≤ 570 nm and a red-light emitting phosphor with an emission band of 590 nm ≤ μ ≤ 630 nm, said device emitting high-quality white light. The colour rendering index CRI is 90 at a colour temperature of 4 000 K. As colour rendering depends only on the composition of the three phosphors and not on the relation of converted to non-converted light it is easyto control and regulate.

Transistor matching in analog CMOS applications

Abstract: This paper gives an overview of MOSFET mismatch effects that form a performance/yield limitation for many designs. After a general description of (mis)matching, a comparison over past and future process generations is presented. The application of the matching model in CAD and analog circuit design is discussed. Mismatch effects gain importance as critical dimensions and CMOS power supply voltages decrease.

Software update manager

Abstract: A method and apparatus for checking/updating existing software on a user's computer (100) utilizes a graphical user interface (GUI). The GUI (16) enables the user, without knowing what software exists on the computer, to download a text file from a remote server (14) and check whether the software on the remote server (14) is contained on the user's computer (100). The user can also download and automatically install a new or updated program via the GUI (16).

Electrically switchable mirrors and optical components made from liquid-crystal gels

Abstract: In liquid-crystal (LC) display devices, patterned electrodes are used to effect switching of molecular orientation within a pixel element, and thin layers of a material (typically a polymer) at the surfaces of the cell plates induce the liquid-crystal molecules to revert to their original orientation after the electric field is switched off1. Because of their periodic variation in refractive index, cholesteric LC phases (which have a helical variation in orientation) reflect light at a wavelength determined by the helical pitch2,3, and so can potentially be used in switchable optical devices such as shutters, reflectors and notch- and band-pass filters. But orientation layers are unable to restore the initial orientation in cholesteric phases. They can instead be given an internal ‘memory’ of their initial orientation by creating an anisotropic polymer network within the system using in situ photopolymerization4. Here we show that such crosslinked cholesteric gels can be used to produce fast electrically switchable reflectors with narrow- to broad-band widths (the latter having a silvery mirror-like appearance). By photopolymerizing in a patterned manner, we can make image recordings in the gels which become visible on application of an electric field. These patterned gels offer the prospect of making optical components such as lenses and gratings by holographic recording.

In vitro and in vivo Raman spectroscopy of human skin

Abstract: Noninvasive techniques that provide detailed information about molecular composition, structure, and interactions are crucial to further our understanding of the relation between skin disease and biochemical changes in the skin, as well as for the development of penetration enhancers for transdermal drug administration. In this study we present in vitro and in vivo Raman spectra of human skin. Using a Raman microspectrometer, in vitro spectra were obtained of thin cross sections of human skin. They provided insight into the molecular composition of different skin layers. Evidence was found for the existence of a large variation in lipid content of the stratum corneum. A simple experimental setup for in vivo confocal Raman microspectroscopy of the skin was developed. In vivo Raman spectra of the stratum corneum were obtained at different positions of the arm and hand of three volunteers. They provided evidence for differences in the concentration of natural moisturizing factor at these positions. q 1998 John Wiley & Sons, Inc. Biospectroscopy 4: S31-S39, 1998

Remote with 3D organized GUI for a home entertainment system

Abstract: A remote control device for a home entertainment system has a GUI with touch screen functionality. The visible part of the GUI is hierarchically organized in several control levels. All levels have consistent lay-outs with a first area for selectable items in a first location, a second area with controls for the selected one of the items in a second location and a third area for content data relating to the selected item in a third location. The spatial relationship between locations and areas is maintained throughout the levels. Such a GUI contributes significantly to the user-friendliness of the home entertainment system.

An improved boundary element method for realistic volume-conductor modeling

Abstract: An improved boundary element method (BEM) with a virtual triangle refinement using the vertex normals, an optimized auto solid angle approximation, and a weighted isolated problem approach is presented. The performance of this new approach is compared to analytically solvable spherical shell models and highly refined reference BEM models for tangentially and radially oriented dipoles at different eccentricities. The lead fields of several electroencephalography (EEG) and magnetoencephalography (MEG) setups are analyzed by singular-value decompositions for realistically shaped volume-conductor models. Dipole mislocalizations due to simplified volume-conductor models are investigated for EEG and MEG examinations for points on a three dimensional (3-D) grid with 10-mm spacing inside the conductor and all principal dipole orientations. The applicability of the BEM in view of the computational effort is tested with a standard workstation. Finally, an application of the new method to epileptic spike data is studied and the results are compared to the spherical-shells approximation.

ZnS precipitation: morphology control

Abstract: ZnS is the most important base material for cathode-ray tube luminescent materials. In order to meet the requirements of various types of luminescent screen, routes to ZnS powder with adjustable particle morphology were investigated. The most important morphological parameters of ZnS phosphors are the particle size and the particle size distribution. Industrially, ZnS synthesis is performed by precipitation in an aqueous medium. Precipitation methods included in this study are homogeneous precipitation, precipitation in liquid crystal phase and the introduction of seeds. The powders received were processed to luminescent materials in a standard manner. The results are discussed in relation to raw ZnS powder properties as well as to the morphology and performance of the resulting annealed phosphor powders. From the methods investigated, the use of seed sols based on nanosized CuS, ZnS and S particles yielded the best results, namely, well-defined phosphor particles of micron-scale diameter.

Navigating through television programs

Abstract: A method of navigating through television programs is disclosed. A television receiver displays a mosaic image with sub-images representing the available programs. The receiver further receives an electronic program guide with program descriptions. Upon activating a 'theme' button (42), the viewer can enter a desired program type, e.g. 'movie'. In response thereto, the brightness of the sub-images representing programs that are not desired is reduced. The user is thus assisted in navigating through programs he is interested in, while maintaining the mosaic structure he is familiar with, and without losing the association between channels and their positions on the mosaic screen.