Cree new package allows LED to shine

American LED giant CREE to the United States Patent and Trademark Office (USPTO) for patent No. 20080272386, has been published in November, is the use of laser cutting (laser ablation or exploitation or sawing) technology directly on silicon carbide (SiC) substrate is provided with grooves (trenches), and then use the method of spin coating or fluorescent semiconductor nanocrystals powder fluorescent material is filled in the groove, forming a convex bridge between the grooves, this method can make the white LED smaller, easier to manufacture.

These fluorescent fillers can convert the narrow frequency band blue light emitted by the GaN LED on the SiC substrate into a broad spectrum white light. Inventor Peter Andrews pointed out that with the current LED in the cup base (submount) and compared with the light conversion material packaging technology, the substrate etched groove is a big progress, because the former will limit the minimum size of white LED. In order to assist the light from the LED, manufacturers will change the shape of the base and improve its reflectivity, while the Cree groove design also has a role in improving the extraction rate.

Andrews pointed out that, in addition to the traditional LED phosphor, the introduction of cadmium selenide (CdSe) and other semiconductor nanocrystals in the groove, but also help to control the luminescence wavelength. Cree recommends using inkjet (inkjet) printing, screen printing (screen printing) and spray gun (airbrush) application system to replace the common spin coating method, the new material into the groove.

Despite the use of new materials and the increase of the wavelength conversion groove design, LED bare crystal still retains the traditional standard electrode structure, so you can continue to package LED, or directly to the use, such as direct application is fixed on the circuit board or substrate.

Cree announced in November that the luminous efficiency of high power white LED with a size of 1 mm * 1 mm can be as high as 161 lm/W. For this new record, Cree said it was the result of the improved grain and packaging technology. The company said that they are about to produce such a record advantage of LED, will continue to introduce innovative technology in the production process, is expected to begin production within a year this highly efficient LED.