Light emitting device
AssigneeNichia Corporation
InventorMotokazu Yamada
Life of this patent
Estimating the term…
Abstract
First and second well layers of a light emitting device emit light of different peak wavelengths so as to produce a mixed light, such as white light having high luminous intensity and high luminous efficiency. A color rendering property of the device can be controlled by adjusting the ratio of the growth numbers of the first and second well layers, and/or the thickness of the barrier layers sandwiching the well layers. The color rendering property can also be controlled by forming the second well layer so as to have a degree of asperity greater than that of the first well layer, or so that a degree of area occupied by dished portions having a thickness which is less than half of an average thickness over a total surface is not less than 10%.
Claims9
A light emitting device comprising:
- an active layer of a multiple quantum well structure, sandwiched between an n-type semiconductor layer and a p-type semiconductor layer;
- said active layer including,
- at least one of first well layers made of nitride compound semiconductor containing In, and
- at least one of second well layers made of nitride compound semiconductor containing In, said second well layer emitting light having a principal peak wavelength longer than that of said first well layer;
- wherein each of growth surfaces of said second well layers is rougher than that of each of said first well layer.
A light emitting device comprising:
- an active layer of a multiple quantum well structure, sandwiched between an n-type semiconductor layer and a p-type semiconductor layer;
- said active layer including,
- at least one of first well layers made of nitride compound semiconductor containing In, and
- at least one of second well layers made of nitride compound semiconductor containing In, said second well layer emitting light having a principal peak wavelength longer than that of said first well layer;
- wherein each of said second well layers has dished portions having thickness less than a half of an average thickness thereof, and an area of the dished portions is not less than 10% thereof.
Dependencies are inferred from the claim text.