Plastic Circuit Boards Research Articles

Micro‐Concentrator Photovoltaics Using Fluidic Self‐Assembly Technology

AbstractThis paper is the first to report a simple and cost‐effective method for modularizing an array of gallium arsenide (GaAs) solar cells on a plastic circuit board using fluidic self‐assembly (FSA) technology and the combination thereof with a polymer lens array to implement micro‐concentrator photovoltaics (micro‐CPV). Using FSA and low‐melting‐point solder, the GaAs cells are successfully self‐assembled into a 2D array in 1 min. Micro‐CPVs consisting of 36 and 256 cells are manufactured by aligning a polymer concentrator fabricated by a drop‐on‐demand droplet dispensed lens array mold on the solar cell array. The micro‐CPVs generate 21.31 and 112.96 mW of power, respectively, under 1 sun AM 1.5G illumination. In each module, only 1.69 and 2.27 mm2 of GaAs are used for producing 1 mW; in other words, the implemented micro‐CPV platform consumes 4.21 and 3.14 times less material than a flat‐panel GaAs array. The proposed method for implementing a GaAs‐based solar cell array enables the efficient fabrication of a compact micro‐CPV with a thickness of only 4 mm owing to the absence of a cooling module. This technology is expected to potentially increase the practical usability of III‐V compound solar cells in the energy industry.

Wireless, intraoral hybrid electronics for real-time quantification of sodium intake toward hypertension management

Recent wearable devices offer portable monitoring of biopotentials, heart rate, or physical activity, allowing for active management of human health and wellness. Such systems can be inserted in the oral cavity for measuring food intake in regard to controlling eating behavior, directly related to diseases such as hypertension, diabetes, and obesity. However, existing devices using plastic circuit boards and rigid sensors are not ideal for oral insertion. A user-comfortable system for the oral cavity requires an ultrathin, low-profile, and soft electronic platform along with miniaturized sensors. Here, we introduce a stretchable hybrid electronic system that has an exceptionally small form factor, enabling a long-range wireless monitoring of sodium intake. Computational study of flexible mechanics and soft materials provides fundamental aspects of key design factors for a tissue-friendly configuration, incorporating a stretchable circuit and sensor. Analytical calculation and experimental study enables reliable wireless circuitry that accommodates dynamic mechanical stress. Systematic in vitro modeling characterizes the functionality of a sodium sensor in the electronics. In vivo demonstration with human subjects captures the device feasibility for real-time quantification of sodium intake, which can be used to manage hypertension.

REALIZATION OF A CONDUCTIVE BRIDGING RF SWITCH INTEGRATED ONTO PRINTED CIRCUIT BOARD

This paper presents a new approach for the realization of RF switches based on the Conductive Bridging Random Access Memory technology (CBRAM). This promising approach allows the realization of RF switches in an extremely simple manner at low cost. For the first time, an RF switch based on a MIM structure is realized with an insulator layer obtained from a commonly used resin deposited by spin coating. The paper reports a RF switch based on CBRAM and demonstrates a device integration onto plastic circuit board (PCB). The realized switch is validated by experimental measurements for a frequency range up to 1.5 GHz with an activation voltage less than 1 V.

High ESD reliability InGaN light emitting diodes with post deposition annealing treated ZnO films

In this work, an on top sputtered varistor-like ZnO thin film is deposited and studied which is light emitting diodes (LEDs) fabrication process compatible. Apply this simplify structure, the extra sintered ZnO varistor which is essentially attached on the plastic circuit board (PCB) together with the conventional LED can be omitted. The well known Electric Static Discharge (ESD) protective junction submount and Conductor Insulator Semiconductor (CIS) submount for the flip chip LEDs application can be also negligible. The grown ZnO passivated LED chips were followed by low temperature post deposition annealing treatments (PDA) to enhance the correspondent electrode adhesive property. The resulted current–electric field (I–E) characteristics showed out a good nonlinear property to accomplish high ESD handling capability. In the demonstrated LEDs application, the proposed devices are shown to have the obvious advantage of enhancing the correspondent ESD reliability from 750V to 2kV and with the high yield rated of 92% as well.

Development of a small semiconductor detector using a printed circuit silicon-board for a personal dosemeter

We developed a small size silicon detector composed of a silicon radiation sensor, an analogue amplifier circuit and a sensor bias filter circuit by using a silicon circuit board for use in digital circuit applications. Our detector could be downsized by forming built-in electrical parts of small thin film on the silicon circuit board with a narrow wiring patterns of 20 μ m width through the Micro Electronics Mechanical System manufacturing process and by eliminating the ceramic case through the direct silicon sensor mounting. Our detector is - 85 % smaller than the commercially available detector using the plastic circuit board that has the same sensor and the same circuit covered with a ceramic case. The physical characteristics, such as the energy response and the linearity to dose equivalent rate, of the newly developed detector were investigated by using Am 241 , Co 57 , Cs 137 , Co 60 gamma-rays and 49–157 keV X-rays.

SOCIT4 collisional-breakup test data analysis: With shape and materials characterization

In this paper we revisit the 1995 Kaman database of the SOCIT4 fragment characteristics with added analysis of a subset of the cataloged fragments from the test. This database was compiled from the last of a series of four hypervelocity impact tests conducted under a U.S. Department of Defense program in 1991–1992. This test targeted a flight-ready, U.S. Transit navigation satellite, yielding collision fragments in the size regime of sub-millimeter through tens of centimeters. Results in this database were used in the 1998 NASA Standard Breakup Model to represent characteristic length (size) and area-to-mass distributions of fragments smaller than 10 cm. In this analysis we explore, in detail, the tabulated fragment material and shape. What emerges is a clear distinction in fragment area-to-mass ratio between primarily metal and primarily non-metal fragments. Metal fragments, which are dominated by aluminum, follow the characteristic curve of increasing area-to-mass ratio with decreasing characteristic length: objects move from the character of large irregular bent shards to that of small solid spheroids. Non-metal fragments, dominated by phenolic/plastic, do not appear to move towards solid spheroids as easily as metals. Also unlike the metals, their area-to-mass ratio curve plateaus in the midsize region (smaller than 1 cm), coinciding with a peak in plate-like, non-metal fragments. The internal structure of the Transit payload, with its phenolic surface skin and packed arrays of plastic circuit boards, certainly governs this plateau behavior. In the small fragment regime (smaller than 4 mm) phenolic/plastic ellipsoidal ‘Nuggets’ dominate the population. They outnumber aluminum ‘Nuggets’ by over four to one. Through this study we gain a more detailed understanding of the collisional-breakup process of this particular payload, but also have begun to determine how these data may apply to other breakups. Our long-term goal is to apply this new understanding to future upgrades of the NASA Standard Breakup Model.

Electron irradiation of polymers and its application to resists for electron-beam lithography

Abstract At the heart of the ongoing revolution in the field of microelectronics is the silicon-integrated circuit. This tiny modular silicon “chip” contains all the elements of an electronic circuit such as transistors, capacitors, etc., inseparably associated and connected to each other by metallic interconnects on the surface of the chip. In the early 196Os, three or four logc circuits, each incorporating perhaps a dozen transistors or other devices, were mounted on a plastic circuit board about 3 × 5 in. in size. Today, upward of 1000 similar circuits can be put onto a silicon chip a few millimeters square. Within a few years,1 extensions of present technology should make it possible to put 10,000 circuits on a similar chip. The continued increase in functional complexity over the past 10 years has been provided by increased chip size, improved device design, changes in topology and technology, and improvements in the photolithographic art.2 The reduction in circuit size has already achieved two major benefits: a sharp decrease in the cost of circuits and a sharp increase in the speed with which logic functions can be performed. These benefits are vividly demonstrated by the proliferation of low‐priced pocket‐sized calculators capable of handling an enormous range of mathematical manipulations.