Sharp Announces Infrared Laser Diode With High Operating Temperature

Nov 8, 2012
Shinya Saeki, Nikkei Electronics
The newly-developed infrared laser diodes. The 5.6mm-diameter product (left) and the 3.3mm-diameter product (right).
The newly-developed infrared laser diodes. The 5.6mm-diameter product (left) and the 3.3mm-diameter product (right).
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Sharp Corp developed an infrared laser diode whose operating temperature is up to 100°C.

The laser diode is targeted at range sensors used for gesture-based operations. Sharp will offer 5.6mm- and 3.3mm-diameter CAN packages.

"By making the most of its high operating temperature and small size, we aim to sell the laser diode for use not only in game consoles and smart TVs but also in mobile devices such as smartphones and tablet computers and automotive devices," the company said.

The laser diode has an oscillation wavelength of 830nm and oscillates in a single mode. Its optical output is 200mW in a continuous oscillation, and its electric power-to-light conversion efficiency is 42%.

The threshold current of the laser diode is 45mA when it is in operation. Its operating current and voltage are 235mA and 2.05V, respectively. Its mean time to failure (MTTF) is about 40,000 hours with an optical output of 200mW and an operating temperature of 100°C.

Sharp's existing infrared laser diode for range sensors has an operating temperature of 60°C and an electric power-to-light conversion efficiency of 35%.

To increase electric power-to-light conversion efficiency at a temperature of 100°C, Sharp made improvements to the p-type clad layer and active layer and the n-type clad layer, which are formed by metalorganic chemical vapor deposition (MOCVD).

Though Sharp did not disclose the details, it said that both materials and thickness were changed from those of the existing product. As for the p-type clad layer, the company said, "We increased extraction efficiency by reducing light absorption inside the layer and reduced driving voltage by reducing thickness to lower resistance."

Sharp will start to ship samples of the laser diode for a price of ¥5,000 (approx US$62.59) Nov 30, 2012. Also, it plans to start volume production Jan 30, 2013, with a production capacity of one million units per month.

Sharp expects 10% market growth per year

Sharp considers that the size of the market for infrared laser diodes for range sensors is about ¥4.5 billion (approx US$56.3 million) in 2011.

"Currently, they are used mainly for game consoles," the company said. "But, when more of them are employed for smart TVs and mobile devices, the market will grow at an annual rate of about 10%."

Sharp expects that the market for infrared laser diodes will further grow in and after 2014 because of the establishment of the market for HDDs using a thermal assist recording method. The company intends to continue the development of infrared laser diodes for those HDDs based on the elemental technologies that were developed this time.