Planar circuit board

Structurally, textile electronic circuits can be classified into two categories conventional electronic component implemented on fabric-based flexible planar circuit board (PCB) and intrinsic functional fiber/yarn-based circuit. 

Conventional components are implemented into a textile substrate, eg, flexible planar circuit board. These conventional components could be sensors, OLEDs, and actuators. The circuit can be achieved by three methods (1) weaving conducting wire, (2) sewing and embroidery technique, and (3) screen print and inkjet. 

This type of coil was prepared from copper cladded printed circuit board material by applying photolithographic techniques. The p.c. board material is available with difierent copper thicknesses and with either a stiff or a flexible carrier. The flexible material offers the opportunity to adapt the planar coil to a curved three dimensional test object. In our turbine blade application this is a major advantage. The thickness of the copper layer was chosen to be 17 pm The period of the coil was 100 pm The coils were patterned by wet etching, A major advantage of this approach is the parallel processing with narrow tolerances, resulting in many identical Eddy current probes. An example of such a probe is shown in fig. 10. 

Before the invention of the planar transistor, many photoresist processes were developed for the manufacture of circuit boards. Experience gained in this area was rapidly transferred to silicon processing, and much of the early work in integrated circuit lithography can be traced directly to circuit board manufacturing. 

Planar modular concept for fluid handling micro-systems with functional modules on top of a Mixed Circuit Board... 

Each cell in this planar stack is connected in series, that is, the positive electrode of one cell is connected to the negative of the next cell and so on. In a block stack this is accomplished by using bipolar plates, but in the L79 we use circuit board traces with tab wire connects to perform the same function as the bipolar plates. The L79 can also be built in a parallel configuration or a series-parallel configuration depending on the current and voltage desired. 

The L79 is a planar variation of some of the construction ideas involved in the L78 stack, as presented in Build Your Own Fuel Cells, which also has printed circuit board for the electrode plates. While working with this material, we realized that flow fields could be routed in the circuit board, so that the material could function for a dual purpose as both a collector plate, and a gas flow field. 

PBO and PBZT films can be made very thin (less than 0.002 in.) and can be impregnated with secondary resins, resulting in a substrate with a dielectric constant less than 2.8, an isotropic planar CTE of 7 ppm per °C or less, and temperature resistance over 250°C. Copper circuits and ground planes can be added by a variety of additive or substrative means, and multilayer circuit boards can be fabricated using plated through holes. Further development of these thin film dielectric substrates should result in interconnection density over 100 times greater than is currently possible with fiber reinforced epoxy multilayer boards. 

This chapter presents an overview of performance plastic polymers in commercial planar and 3-dimensional circuit board products, and describes in detail one approach (two-shot molding) developed as an integrated 3-D circuit manufacturing technology. The distinctions between conventional planar (2-dimensional) circuitry, based on thermoset laminates and "subtractive etching processes, and the enhanced design flexibility afforded by expanded interconnection capacity in three axes are discussed. Specific examples of 3-dimensional interconnect protoypes and products are described and pictured. 

Printed circuits are generally planar objects. Usually square or rectangular, they are essentially flat platforms supporting interconnect networks on which are mounted a mixture of electronics or electrical components. These components may be leaded devices (either radial or axial) passing through the board, or mounted components on the board surface. The circuit board acts as a "customizing" device, linking standard or special components to create circuit functionality. (2)... 

Schmitz et al. [25] demonstrated a planar fuel cell design based on printed circuit board (PCB) technology. This planar design consists of an open cathode side which allows a completely passive, self-breathing operation. Power densities of 100 mW cm" at 500 mV with hydrogen were achieved. Long-term operation for more than 1,500 h has been demonstrated. 

For patch clamp measurements, the PDMS planar electrode array was plasma oxidized and then motmted in the recording system shown in Fig. 6. To electrically isolate each electrode, the partition was sealed onto the chamber bottom over an array of openings that each contained an Ag-AgCl wire and suction tubing. The Ag-AgCl wire was connected to the multiplexer chip mounted on the circuit board under the chamber. The multiplexer then connected to the input of the amplifier. The tubing connected to a suction manifold that permitted individual or global suction. 

Hyejung, K., Yongsang, K., Binhee, K., Hoi-Jun, Y., 2009. A wearable fabric computer by planar-fashionable circuit board technique. In Wearable and Implantable Body Sensor... 

Usually the hot-bar blade is attached to a self-leveling, spring-loaded bonding head that allows the blade to self-planarize in relation to the underlying component leads and circuit board surface. Nonetheless, variations in board contour, such as a locahzed high or low spot, can render the concept of self-planarization useless and solder opens can result. Rigid-member hot-bars are excellent for accommodating differences in lead coplanarity because the blade... 

We have demonstrated a novel method to create either fi eestanding or surface-boxmd wires capable of establishing electrical contacts between isolated metal structures. The technique relies on spatially coupled electrodissolution and electrodeposition mediated by an electric field. Such bipolar conditions avoid the need to physically contact the metallic components in the system, which should prove to be a considerable advantage when dealing with far smaller components. In the case of wire formation on circuit boards, the metallic paths laid down serve as templates for an electroless deposition step, which yields robust and adherent electrical connections. In principle, the method is not limited to planar geometries. The application of electric field vectors in selected directions through an array of conductive structures in a porous medium may represent a powerfijl approach to the formation of three-dimensional circuitry. Furthermore the use of a conductive polymer allows the use of metal structures which do not electrodissolve in the medium. 

Planar thin-film technology is applied directly on the fabric to develop a FCB. It allows the implementation of a circuit board on a plain fabric patch for wearable electronic applications. It features a soft and flexible impression, just as normal clothes do. 

Lee, S., et al., 2010. Arm-band type textUe-MPS player with multi-layer planar fashionable circuit board (P-FCB) techniques. In ISWC, pp. 1-7. 

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