LED ELEMENT

摘要

In order to achieve appropriate light distribution using light distribution characteristics resulting from diffraction while improving light extraction efficiency using a diffraction effect, an LED element provided with: a substrate in which periodic depressions or projections are formed on a front surface; a semiconductor laminated part that is formed on the front surface of the sapphire substrate, includes a light-emitting layer, and is formed of a group-III nitride semiconductor; and a reflecting part that reflects at least a part of light emitted from the light-emitting layer toward the front surface of the substrate, the LED element obtaining a diffraction effect of light emitted from the light-emitting layer at an interface between the substrate and the semiconductor laminated part, wherein a relation of 1/2×λ≦P≦16/9×λ, is satisfied, where a period of the depressions or the projections is P and a peak wavelength of the light emitted from the light-emitting layer is λ.

主权项

1. An LED element comprising:
a sapphire substrate in which periodic depressions or projections are formed on a front surface and the front surface forms a diffractive surface; a semiconductor laminated part that is formed on the front surface of the sapphire substrate, includes a light-emitting layer, and is formed of a group-III nitride semiconductor; and a reflecting part that reflects at least a part of light emitted from the light-emitting layer toward the front surface of the sapphire substrate, wherein a diffraction effect of light emitted from the light-emitting layer is obtained at an interface between the sapphire substrate and the semiconductor laminated part, an intensity distribution of the light transmitting through and extracted from the diffractive surface close to the sapphire substrate is inclined closer to a direction vertical to the interface between the semiconductor laminated part and the sapphire substrate than an intensity distribution of the light incident on the diffractive surface close to the semiconductor laminated part, a relation of 1/2>λ≦P≦16/9×λ is satisfied, where a period of the depressions or the projections is P and a peak wavelength of the light emitted from the light-emitting layer is λ, and the reflecting part is formed of a laminated structure of a dielectric multilayer film and a metal layer, and the reflectivity of the reflecting part increases as an angle comes closer to the direction vertical to the interface.