Last month, the U.S. government granted $37 million to 17 projects developing light-emitting diodesfor various applications ranging from lighting systems to screen technologies. All the while, ongoing research and development is finally driving down the costs and increasing the efficiency of LEDs and their organic, increasingly popular cousins. With lifespans exceeding 50,000 hours, LEDs have incandescent and fluorescent light bulbs beat hand down. But so far they have been prohibitively expensive. Most of the work taking place at big companies like Cree and Bridgelux are all about bringing down these costs to make the technology practical for everyday consumers. It’s one thing that Rockefeller Center’s iconic tree was lit with LEDs last year — it’s quite another for average homeowners to be buying LED fixtures at Ikea. Now, a stream of recent news makes this area look even more promising:

Philips sees results: Foreshadowing broader adoption, electronics giant Philips announced that LED-based lighting accounted for more than 10 percent of its lighting sales in the third quarter of 2009. This prompted predictions that LED technology, or solid-state lighting as it is sometimes called, will grow annually at a rate of 24 percent, transforming into a $15 billion business by 2013.

Cree reports strong earnings: Public LED company Cree (CREE) just announced solid earnings for its second fiscal quarter. Following a big deal to supply 650 Wal-Mart Stores with LED lighting systems, the company reported a 35 percent increase in revenue, totaling $199.5 million. Profits also jumped from $10.7 million the previous year to $33.8 million. As a result, its stock price went up 9.7 percent to $59.49 a share. Today, it’s back down to $56.11.

Bridgelux eyes cost drops: LED maker Bridgelux says that prices for LED fixtures designed to replace burnt out incandescents will drop sharply this year. They could even come in under $10 by the end of 2010 — eight times cheaper than they are currently being marketed for. Bridgelux has also recruited a new CEO, former Seagate chief Bill Watkins, signaling a new, more aggressive strategy.

More lumens for your buck: Seoul Semiconductors‘ Ariche brand has unveiled the first LED bulb to hit 100 lumens per watt — said to be 25 percent more efficient than its competitors’ runners up. Ariche’s products don’t require an AC-DC converter. This means that LEDs can be used in shapes that otherwise wouldn’t accomodate solid-state lighting. It also avoids the energy losses inherent in standard power converters. The company also claims that the carbon emitted by its LED systems is 10 percent of that emitted by incandescent bulbs.

Combined, the news coming out of these four companies, and the government’s stimulus investment in LED development could make 2010 the year that LEDs finally invade the home.