| 摘要 |
To increase the amount and/or directionality of light from a light emitting diode (LED) 1 located on or in a semiconductor substrate (2), a first side of the diode which faces away from the substrate is provided with a reflector (3) (shown as a mirror electrode on a second larger substrate (4), but it may be a specular coating on the LED), and the substrate (2) includes an optical focussing (e.g. Lens), interference (e.g. Fresnel lens) or diffractive (e.g. grating) element (5) adjacent a second side of the diode opposed to the first side. Preferably the element (5) is formed within the thickness of the substrate (2) by etching downwards from the surface remote from substrate (4). The height variation in a grating element (5) may be binary or multi-valued, and the grating may be one two or three-dimensional. The side of the LED adjacent reflector (3) may be curved. |
