Motorola Corporation

Bobby Dean Landreth

Robert W Pennisi

Sivakumar Muthuswamy

Steven Duane Pratt

Ronald James Kelley

James L Davis

Fadia Nounou

Robert J Mulligan

Glenn F Urbish

David S Fredley

A direct methanol fuel cell systemuses dissolved catalyst to promote a fuel cell reaction that takes place in an anode sub-chamberof a fuel cellAccording to the preferred embodiment the dissolved catalyst comprises a macro cyclic coordinated compound of platinum. The dissolved catalyst is preferably continuously circulated through the anode sub-chamberand is preferably mixed in a mixing valvewith methanol and water in order to promote its catalytic action.

Fuel cell system

Rewritable signs () that include bistable cholesteric liquid crystal layers () are provided. According to one embodiment a rewritable sign () is devoid of circuitry for establishing electric fields in localize regions for writing information to the rewritable sign (), and is consequently inexpensive. In the latter embodiment, a separate information writer () that includes an array of pixel electrodes () that is driven by an active matrix () is used to write information on the rewritable sign. According to another embodiment a rewritable sign () includes three cholesteric liquid layers () each of which reflects a different primary color. The three cholesteric liquid crystal layers () are interleaved with sets of conductive lines () that are used to apply signals to the cholesteric liquid crystal layers () for the purpose of writing information.

Rewritable sign system

The invention provides a device for generating energy, utilizing a fuel cell. Air is freely guided to the fuel cell, while a fuel gas is provided to the fuel cell from a pressurized fuel supply via a regulator. The portable power supply is most applicable to use with handheld electric devices, and contains a fuel storage means (,) for storing a supply of fuel, a fuel delivery means (,) connected to the fuel storage means, an energy conversion device (,) connected to the fuel delivery means for converting the fuel to electricity. The fuel storage means, the fuel delivery means, and the energy conversion device are all contained in a volume less than 500 cubic centimeters.

Portable fuel cell power supply

A membrane electrode assembly consists of a polymer electrolyte membrane (,) with an electrode on each side. The polymer electrolyte membrane has an integral sensor (,) disposed on the surface. The sensor monitors the physical, thermal, chemical or electrical state of the membrane electrode assembly. Information obtained from the sensor is used to identify a defective membrane electrode assembly, and the operation of the fuel cell is altered based on the identified defective membrane electrode assembly.

Integral sensors for monitoring a fuel cell membrane and methods of monitoring

An ultrasonically welded joint is made by placing a thermoplastic film (,) between two thermoplastic members (,). The two thermoplastic members each have a mating part of a complex joint. One part of the joint, known as the shear joint (,), serves to shear away part (,) of the film when the two members come together, and another section of the same joint, known as the mash joint (,), serves to bond the film and the two members all together during the ultrasonic welding process.

Ultrasonic welding process

A planar fuel cell (20) is provided, including a membrane electrode assembly (23) sandwiched between two current collector assemblies (21, 22). The membrane electrode assembly is a single sheet of a polymer electrolyte membrane with an array of anodes (27) on one side and an array of corresponding cathodes (28) on the other side. The current collectors (25) can be supported by a plastic frame (24), and they have an interconnect tab (26) that provides an electrical pathway to the exterior of the membrane electrode assembly. The interconnect tab is situated to provide electron transfer between the anodes and the cathodes such that the interconnect tab does not traverse the thickness of the polymer electrolyte membrane. When the planar fuel cell is assembled, the interconnect tab is sealed to prevent leaking of fuel or oxidant gases. Fuel is distributed (36) to only one side of the membrane electrode assembly and oxidant is distributed (36) only to the other side.

Planar fuel cell

Solder pastes having vehicles including formic acid-soluble organic acids as fluxing agents are described. Fluxing agents may be compounds of the formula: ##STR1## where R is an electron withdrawing group. In one embodiment, R is selected from the group consisting of fluorine, chlorine, bromine, iodine, sulfur, hydroxyl, nitrile, and benzyl. Other suitable formic-acid fluxing agents include, but are not limited to, adipic acid, acrylic acid, polyacrylic acid, methacrylic acid and polymethacrylic acid. The compounds clean oxides from the printed circuit boards (PCBs) under assembly and then volatilize leaving a residue to be cleaned away. The cleaning step involves rinsing with formic acid. No undesired residue remains indicating that the organic acids of the invention are effective in cleaning boards. Such acid fluxing agents can be used mixed with typical solder components, such as lead/tin solder pastes, or applied topically to solders, such as solder balls; both techniques permit the assembly of PCBs more easily with high quality bonds, and with little or no residue. Malic acid is a preferred organic acid fluxing agent. The formic acid cleaning step may be followed by a water rinse.

Method of cleaning printed circuit boards using formic acid

Solder pastes having vehicles including blends of low boiling point alcohols and relatively high boiling point alcohols are described which leave residues which may be cleaned using only water are described. The low boiling point alcohols have a boiling point range of between about 65.degree. and about 150.degree. C. whereas the high boiling point alcohols have a boiling point in rhe range of about 150.degree. to about 270.degree. C. The solder pastes also use water-soluble organic acids as fluxing agents such as compounds of the formula: ##STR1## where R is an electron withdrawing group such as fluorine, chlorine, bromine, iodine, sulfur, hydroxyl, nitrile, and benzyl. Other suitable formic-acid fluxing agents include, but are not limited to, adipic acid, polyacrylic acid, methacrylic acid and polymethacrylic acid. The compounds clean oxides from the printed circuit boards (PCBs) under assembly and then volatilze leaving a residue to be cleaned away. The cleaning step involves rinsing with water. No undesired residue remains indicating that the organic acids of the invention are effective in cleaning boards. Malic acid is a preferred organic acid fluxing agent.

Method of cleaning printed circuit boards using water

Fluxing compositions are described containing as fluxing agents compounds of the formula: ##STR1## where R is an electron withdrawing group. In one embodiment, R is selected from the group consisting of fluorine, chlorine, bromine, iodine, sulfur, hydroxyl, nitrile, and benzyl. The compound cleans oxides from the printed circuit boards (PCBs) under assembly and then volatilize with little or no need for a cleaning step, or cleaning only with water or formic acid. Very little or no undesired residue remains. Such acid fluxing agents can be used mixed with typical solder formulations, such as lead/tin solder pastes, or applied topically to solders, such as solder balls; both techniques permit the assembly of PCBs more easily with high quality bonds, and with little or no residue. Malic acid is a preferred organic acid fluxing agent.

Use or organic acids in low residue solder pastes

Fluxing compositions containing compounds that generate acids upon photoinitiation from a light source such as Hg/Xe ultraviolet (UV) light sources are described. The acids clean oxides from the printed circuit boards (PCBs) under assembly and then volatilize with little or no need for a cleaning step, or cleaning only with water. The compounds that release an oxide removing agent, sometimes called a 'photoacid' include metal and organic onium salts and furyl compounds bearing a carbonyl group. Such fluxing compositions can be used mixed with typical solder formulations, such as lead/tin solders, or applied topically thereto; both techniques permit the assembly of PCBs more easily and with high quality bonds.

Solder fluxes bearing oxide removers generated by light

Solder paste vehicles using blends of monofunctional and polyfunctional alcohols are described. The blend may have a major portion of a low viscosity, monofunctional alcohol solvent and a minor portion of a high viscosity polyfunctional alcohol thickener. The monohydric solvent has a room temperature viscosity of at least 3 centipoise and from about 3 to 18 carbon atoms and may include such materials as 2-butanol, 1-hexanol, 1-heptanol, 1-octanol, 1-nonanol, 1-dodecanol, 2-ethoxyethanol, 2-(2-ethoxyethoxy)ethanol, 2-(2-butoxyethoxy)ethanol, n-hexadecanol, n-octadecanol, benzyl alcohol and mixtures thereof. The polyalcohol has a room temperature viscosity of between about 26 to about 1500 cp and includes compounds such as 1,2-ethanediol; 1,2-propanediol; 1,3-propanediol; 1,2-butanediol; 1,3-butanediol; 1,4-butanediol; 1,2-pentanediol; 1,5-pentanediol; 2,4-pentanediol; 2,5-hexane-diol; glycerol; 1,2,4-butanetriol; 2,2'-(ethylenedioxy)diethanol; 1,12-dodecane-diol; 1,16-hexanedecanediol and mixtures thereof. These blends give improved solubility of organic acid fluxing agents, provide relatively high viscosities of the solder paste and permit lower amounts of solvent to be used.

Growing community of inventors

Ft. Lauderdale, FL, United States of America

Bobby Dean Landreth