Small Times - Printable electronics and photonic curing: high performance in a flash - Sent Using Google Toolbar

Small Times - Printable electronics and photonic curing: high performance in a flash

Printable electronics and photonic curing: high performance in a flash
By Steve Leach, NovaCentrix

The silicon industry has achieved stunning advances over its nearly 50 year history. Every new generation of technology has offered increased computing power, faster operating speeds, and lower costs, which have enabled electronics to penetrate every facet of our lives. There remain, however, potential applications for which conventional silicon technology is not viable, either due to cost, fragility, or time to market considerations. For such applications, printable electronics is a new disruptive technology.

Printable electronics represents the merger of electronics and printing. The concept is to use high speed printing equipment to build electronic devices using specialized inks that when cured provide the basic building blocks of circuits: conductors, resistors, semiconductors, and dielectrics. Compared to standard equipment for manufacturing semiconductors and electronics, printing equipment is fast, inexpensive, and large area ( i.e. "wide-web"), factors which together enable the promise of low cost and large area printable electronics.

The range of applications for printable electronics is quite large, encompassing RFID tags, flexible displays, sensors, photovoltaics, batteries, lighting, and logic and memory. The ability to print on common packaging materials will further extend applications into product branding and value-added packaging. The recent formation of industry initiatives around printable electronics is validation of the potential impact of printable electronics. For example, iNEMI's "2007 International Electronics Manufacturing Initiative Roadmap" will include a section on organic and printable electronics. That document is scheduled to be available to the public in February 2007.

Click here to enlarge image

The chart shows an optimized cure routine for silver film on Mylar based on photonic cure resistivity data for a 2.5 micron thick silver film. Data courtesy of NovaCentrix.

Printable electronics is still an emerging technology, and there are technology gaps to be met before widespread adoption can occur. One such gap is the need for low temperature curing (or sintering or annealing) methods. Conductive inks, for example, are typically metallic-based, and must be sintered to realize high conductivities, which requires time and temperature. Lower temperatures generally mean longer processing times. A cure time of one minute on a 2,000 FPM (feet per minute) web necessitates a curing oven with nearly a half mile heated web path. Higher temperatures, on the other hand, can reduce the sintering time, but at the cost of requiring expensive substrates that can withstand the high temperatures. What is needed is a low temperature and rapid process for curing or sintering.

In response to this need, NovaCentrix has developed "photonic curing" technology, a low temperature, rapid sintering process. NovaCentrix Photonic Curing Systems instantly cure metal nanoparticle-based inks by exposing them to a brief, intense pulse of light from a xenon flash lamp. The system rapidly and selectively heats and fuses nanoscale metallic ink particles, forming highly conductive traces without heating the base substrate material. The technology operates at room temperature and is very fast. The energy is broadcast over the whole substrate with no need for shadow masks or expensive alignment techniques, and since it is in the form of light rather than heat, the energy will not damage thermally sensitive components or materials.

Photonic curing technology relies on the physical properties of nanoparticles. Metal nanoparticles are generally black and light absorbing. They have a high surface area to mass ratio, requiring very little light to heat them. A continuous source of radiation will heat the particles and within a few milliseconds they will transfer heat to the substrate. If the source of radiation is pulsed, with a duration that is shorter than the thermal equilibration time of the particles and substrate, then the nanoparticles will quickly heat and sinter before they can transfer much energy to the substrate.

The ideal radiant energy appears to be on the order of 1 J/cm2 delivered in about 1 ms for most systems of interest. Longer pulses require more energy to cure the particles and transfer too much heat to the substrate. Shorter pulses can vaporize smaller particles in the film, build up thermal gradients in the substrate, and explosively blow apart the film. Ideal curing conditions are determined by the particle type, size, film thickness, substrate type, substrate thickness, and particle binder system.

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NovaCentrix has built a research and development system, the PCS-1100, for developing printable electronics applications or materials. The cure area, areal energy density, and the pulse length of the arc discharge are all adjustable. Photo courtesy of NovaCentrix

Photonic curing utilizes xenon strobes as a light source rather than lasers. Xenon strobes are preferable for several reasons. For example, lasers are far more complex and expensive devices. In addition, xenon strobes are far more efficient in converting electrical energy to light, with conversion efficiencies typically in the 50 percent range, which is 10 times greater than what is possible with the type of laser needed to cure metal particle-based films.

The technology behind photonic curing is closely related to NovaCentrix's proprietary nanoparticle synthesis process, which begins with two metal rods in an enclosed tank. A high-power pulsed arc discharge (50 to 100 kA over 1ms duration) is drawn between the rods in an atmospheric pressure gas. The material at the end of the rods is ablated and heated to form a high-pressure (10-100 Atm) metal plasma. The plasma supersonically expands and quenches, yielding nanometer sized, single crystal, unaggregated particles in a gas suspension. These particles are conveyed out, collected, the rods are indexed in toward each other, and the process is repeated. The pulse frequency controls the production rate. By changing the composition of the quench gas from inert to reactive, either metals or metal compounds can be made.

Photonic curing uses a similar process to generate the intense light needed to cure nanometal-based films. The arc discharge is lower, so as to remain below the threshold that would normally ablate the electrodes and make nanoparticles. Even with the lower power discharge, the radiation is still dramatically more intense than that from a typical camera strobe. Just as with the nanoparticle synthesis process, the pulse duration and intensity can be varied, providing independent control over both the power and energy delivered to a surface.

Besides low temperature curing, there are additional benefits of photonic curing that make it suitable for printable electronics.

  • By reducing the time to cure to less than a millisecond, photonic curing can be compatible with high-speed printing processes such as gravure and flexography without a large amount of dedicated floor space. In essence, the time to cure becomes matched to the time to print.
  • The process is suited to nanoparticle-based materials, which also makes it well-suited to high resolution deposition methods and applications.
  • The speed with which sintering occurs makes it possible to cure copper in air, which normally must be cured in an inert or reducing environment. NovaCentrix has demonstrated curing nano-copper based conductive inks in air, achieving resistivities below 40X bulk. This benefit opens the door to the use of inks that use lower cost materials.
  • Once a material has been sintered, it will typically no longer absorb light. Thus there is the potential for building multilayer circuitry that does not thermally stress the underlying layers.

NovaCentrix has built a research and development system to scan curing conditions to optimize the conductivity of several films and substrates. The cure area, areal energy density, and the pulse length of the arc discharge are all adjustable.

When customers develop applications taking advantage of the benefits of photonic curing, there will be a need for high volume, continuous feed curing systems. In anticipation of this need, NovaCentrix is developing such systems, and has recently delivered a pilot-scale unit designed to cure Metalon branded inks on continuous films at speeds up to 50 feet per minute. NovaCentrix will continue developing high-speed commercial systems for integration with ink-jet, flexographic and gravure printing systems. These are intended to enable or accelerate the commercialization of printable electronics in RFID tags, displays, photovoltaics and other applications.

Steve Leach is chief executive officer of NovaCentrix (www.novacentrix.com) in Austin, Texas.

Small Times January, 2007
Author(s) :   Steve Leach

High Court Appears Willing to Limit Licensing Fees for Patent Owners - WSJ.com - Sent Using Google Toolbar

High Court Appears Willing to Limit Licensing Fees for Patent Owners - WSJ.com

High Court Appears Willing to Limit
Licensing Fees for Patent Owners

January 17, 2008; Page B4

WASHINGTON -- The Supreme Court yesterday seemed ready to roll back a patent holder's power to control the use of its invention after it has been sold to somebody else.

Separately, the justices upheld New York state's system of selecting judicial nominees through political conventions, despite claims that the practice locks out independent challengers to party machines.

In the patent case, LG Electronics Inc. of South Korea licensed Intel Corp. to make computer chips but demanded a second royalty from companies that bought the Intel chips and used them to assemble computers.

One of those companies, Quanta Computer Inc. of Taiwan, argued that LG was demanding more than patent law allowed. The license to Intel exhausted the patent claims, the company contended. Since the chips have no use other than as a computer component, it would make no sense to license their sale but forbid installing them in computers, it said.

Several justices seemed to agree. "What you are trying to do is expand what you get," Chief Justice John Roberts told LG's attorney, Carter Phillips. "And the reason that troubles me is because if you had imposed a condition on the sale, Intel wouldn't have paid you as much."

The U.S. Court of Appeals for the Federal Circuit, a specialized tribunal that hears patent appeals, had agreed with LG. But in recent years the Supreme Court has overruled a raft of Federal Circuit decisions that gave patentees broad power to control their inventions and made it difficult for competitors to challenge the validity of patents.

A decision is expected by July.

(Quanta Computer Inc. v. LG Electronics)

Separately, the court unanimously rejected claims that New York's method of selecting judicial nominees violates the First Amendment.

A former Brooklyn judge had sued, claiming that party bosses shut her out of the Democratic nomination after she refused demands to make patronage hires. Under the system, voters elect delegates to a partisan judicial nominating convention, which selects candidates for the general election. With most districts under effective one-party control, nomination was tantamount to election, critics argued.

Writing for the court, Justice Antonin Scalia said that the system provided adequate alternatives for challengers to get their names on the ballot at the general election. Several justices noted that the court wasn't endorsing New York's Byzantine system.

(New York State Board of Elections v. Lopez Torres)

Write to Jess Bravin at jess.bravin@wsj.com

Researchers find five cups of coffee per day may keep Alzheimer's away | Nevada Appeal | Serving Carson City, Nevada - Sent Using Google Toolbar

Researchers find five cups of coffee per day may keep Alzheimer's away | Nevada Appeal | Serving Carson City, Nevada

Researchers find five cups of coffee per day may keep Alzheimer's away

Photo by Jim Grant / Tahoe Daily Tribune
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Sindri Azpeitia of Wide Awake Conscious Cafe brews a fresh cup of coffee Tuesday. A new study says caffeine helps reduce the risk of developing Alzheimer's disease.
Jim Grant / Tahoe Daily Tribune

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Jennie Tezak, jtezak@tahoedailytribune.com
January 16, 2008, 6:00 AM

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If you load up on java in the morning, you may be reducing your risk of getting Alzheimer's disease.

Long-term intake of caffeine has been shown to reduce the risk of Alzheimer's disease in mice that develop the disease.

In a study just published online in the journal Neuroscience, researchers at the Byrd Alzheimer's Institute in Tampa, Fla., reported that caffeine intake equivalent to five cups of coffee per day in humans protects mice with Alzheimer's against further memory impairment and reduces Alzheimer's pathology in their brains.

An earlier study in humans indicated that Alzheimer's patients consumed markedly less caffeine during the 20 years preceding disease diagnosis compared with age-matched individuals without Alzheimer's disease.

"We wanted to test the ability of dietary caffeine intake to protect against Alzheimer's disease in a highly controlled study in Alzheimer's mice where the only variable that was different between groups was whether caffeine was in their drinking water or not," Gary Arendash, lead researcher in the study, said on the institute's Web site. "We were surprised to find that Alzheimer's mice given caffeine in their drinking water throughout adult life performed much better than Alzheimer's mice not given caffeine and very similar to normal mice without the disease."

When asked at various coffee shops in South Lake Tahoe, regular coffee drinkers voiced their opinions on this study and whether or not they would drink more coffee based on it.

At Alpen Sierra Coffee Roasting, Don Schlotz read a newspaper Tuesday as he sipped his coffee. Schlotz is a regular coffee drinker and drinks one cup per day.

"It sounds good to me," Schlotz said when asked about the study. "I hope it does decrease the risk."

Schlotz said he would not increase his coffee drinking based on the study.

"Before, they were saying coffee causes problems; now they're saying that's not really true," he said. "It's important to do everything in moderation. Coffee has some benefits."

Coffee drinker Rick Karsner, who was visiting South Lake Tahoe from the Bay Area, is a regular coffee drinker. He drinks coffee daily and lattes three or four times per week. When asked about the study, Karsner was not quite convinced.

"I'd say disbelief is my reaction," he said. "Coffee is 98 percent water. So what little is in there is already filtered. I'd have to see the data."

Karsner said he might increase his coffee drinking if he saw proof regarding the study.

Holland resident Valerie Thompson drinks five cups of coffee per day, which is the exact amount found to be beneficial in the study. When asked about the study, she said it wouldn't change her coffee consumption.

"It would be nice," Thompson said regarding the study. "I just drink what I like. I just do what I like to do, not because it's better for my health."

South Lake Tahoe resident Cash Lebish drinks two cups of black coffee per day.

"I'm glad they found that information," he said. "It wouldn't stop me either way, though. It's good that coffee has a positive effect."

Giuliani Targets Conservatives With Tax-Cut Plan - WSJ.com - Sent Using Google Toolbar

Giuliani Targets Conservatives With Tax-Cut Plan - WSJ.com

Giuliani Targets
With Tax-Cut Plan

January 10, 2008; Page A8

(See Corrections & Amplifications item below.)

WASHINGTON -- Republican presidential candidate Rudy Giuliani made a bid for his party's tax-cutting wing, unveiling a plan to trim capital-gains rates and simplify the tax code.

Mr. Giuliani proposed many ideas common among the Republican candidates: extending the 2001 and 2003 tax cuts, repealing the estate tax, and eventually eliminating the alternative-minimum tax for individuals. He also backed reducing the corporate-tax rate to 25% from 35% and dropping the capital-gains rate to 10% from 15%.

In a move to appeal to Republican primary voters frustrated with the complexity of the tax system, Mr. Giuliani proposed giving filers an option of filling out a one-page income-tax form, coupled with three tax brackets with rates of 10%, 15% and 30%. He called it the "Fair and Simple Tax" form, or FAST.

The former New York mayor cast his tax plan as an effort to stimulate the economy and encourage businesses to keep hiring workers as many voters are reporting economic security at the top of their lists of concerns.

[Rudy Giuliani]

"At a time when many Americans are worried about the economy, now is the right time to cut taxes so we can put America back on a pro-growth path," Mr. Giuliani said.

His plan had a more conservative tinge than might have been expected from a candidate who has been focused on attracting the center of his party. His campaign, now focused on winning the Jan. 29 Florida primary, put out a statement calling him the "real fiscal conservative running for president."

Among the Republican candidates' plans, Mr. Giuliani's appeared most similar to that of Fred Thompson, who has been a favorite of conservatives but is lagging behind in the polls. The conservative Club for Growth praised both candidates' plans. Both Messrs. Giuliani and Thompson proposed voluntary, simplified methods for individuals to file their taxes.

Mr. Giuliani's plan is "exactly the kind of plan economic conservatives should embrace," Club for Growth President Pat Toomey said. He said the proposal would "reward hard work, encourage investment and promote economic growth for Americans across the economic spectrum."

The antitax group Americans for Tax Reform also praised the Giuliani plan.

Mr. Thompson's proposal would go further than Mr. Giuliani's. The former Tennessee senator proposed a flat tax with two rates. He also would eliminate the deductions and credits in the tax code. Mr. Giuliani would retain deductions for mortgage interest, charity, and state and local taxes, among others.

Mike Huckabee has proposed a far different approach: scrapping the income tax and replacing it with a national sales tax. The Club for Growth has been hammering Mr. Huckabee over the proposal, which critics say is unworkable and unlikely to get through Congress. But the former Arkansas governor's plan turned out to be a strong attraction for Republican voters in Iowa, where he won the caucuses with his populist message.

Former Massachusetts Gov. Mitt Romney also has proposed extending the 2001 and 2003 tax cuts and repealing the estate tax. He put forward a unique proposal among the candidates: to eliminate taxes on capital gains and dividends for people earning less than $200,000.

Arizona Sen. John McCain has been criticized by some on the right for opposing past tax cuts promoted by President Bush, which he has said he did only because the lost revenue wasn't offset with spending cuts. Mr. McCain backs extension of the 2001 and 2003 tax cuts, with spending cuts as offsets. He supports eliminating the alternative-minimum tax and reducing corporate rates.

If the Republicans' tax proposals have substantial common ground, they present a contrast to the approach of Democratic candidates. The theme among the Democratic front-runners has been directing tax cuts at lower- and middle-income people, and paying for them by increasing taxes on wealthier people. They have said that at least some of the 2001 and 2003 tax cuts should be allowed to expire, as scheduled, in 2010.

Write to Sarah Lueck at sarah.lueck@wsj.com

Corrections & Amplifications:

The Club for Growth hasn't taken a position on the substance of Mike Huckabee's "fair tax" proposal, instead focusing its criticism on his tax record while governor of Arkansas. This article incorrectly said the Club for Growth has been critical of Mr. Huckabee's proposal.