Toshiba demonstrated the use of simple technology to make the efficiency of LED light doubling technology

Toshiba has developed the light emitting diode (LED) light output efficiency increased to more than 2 times, the comprehensive exhibition of "international nanotechnology and in February 21, 2006 the opening of the Nano Tech 2006" in aspects of display panels. The concave convex structure is formed on the surface of the LED chip, which improves the optical output efficiency. Here are 2 times the results of the package before the LED chip itself compared results.

The concave convex structure of high 300nm ~ 500nm can be formed by 150nm to 200nm interval along the width direction of the LED chip surface, and the light of the light emitting layer can be prevented from being reflected by the light emitting surface. The efficiency of the light gain is improved by the variation of the concave convex period and the channel depth due to the refractive index of LED and the wavelength of luminescence.

By using the refraction effect of light, it is very easy to make the light passing through the angle of incidence greater than the critical angle. This technique can also prevent the reflection of light incident at an angle less than the critical angle.

Using self assembly to form the concave convex structure

The technology can only use heat treatment and dry etching to form a concave convex structure. The manufacturing method of the concave convex structure is as follows: firstly, the polymer is coated on the compound semiconductor by spin coating method. By heating treatment, so that "self assembly", polystyrene will condense into a point. Under normal circumstances, the diameter of only about 50nm, but it is said that Toshiba has taken some measures to make the diameter of more than 100nm.

Thereafter, the PMMA is removed by dry etching, and the remaining polystyrene is used as a mask pattern formed on the compound semiconductor. Then, in order to form the concave convex structure on the compound semiconductor, dry etching is performed again. Finally, oxygen was used to remove polystyrene.

The manufacturing method allegedly used Toshiba for the development of hard disk Media (Patterned) technology.

Although the company said to maintain reproducibility of the concave convex structure in the research stage, but this technology was put into production, but said the production and reproduction of the concave convex structure as polymer materials, use of mask material production has some problems to be solved. In addition, the yield for the production problem, the company said it is not clear.