| 摘要 |
To increase the amount and/or directionality of light from a light emitting diode (LED) 1 supported on a substrate 2, the side of the diode remote from the substrate is provided with an additional layer 5 in which is formed a diffractive (grating) or interference (Fresnel lens) optical elemental 4 of varying thickness. The construction is particularly useful in the infra-red, where the thickness variation cannot be built into the LED structure itself. Layer may be formed during manufacture of the LED, or secured thereto by an optically thin layer of adhesive. |
