Illumination apparatus

Abstract

An illumination apparatus comprises a plurality of LEDs aligned to an array of directional optical elements wherein the LEDs are substantially at the input aperture of respective optical elements. An electrode array is formed on the array of optical elements to provide at least a first electrical connection to the array of LED elements. Advantageously such an arrangement provides low cost and high efficiency from the directional LED array.

1 - 15 . (canceled) 
     
     
         16 . An illumination apparatus, comprising:
 a non-monolithic array of light-emitting elements, wherein:   the light-emitting elements of the non-monolithic array have been removed from an epitaxial monolithic layer on a growth substrate,   the removal of the light-emitting elements comprised illumination of the light-emitting elements through the growth substrate,   the light-emitting elements are arranged in the non-monolithic array with their original spatial positions relative to each other in the epitaxial monolithic layer preserved,   wherein, in at least one direction, for at least one pair of the light-emitting elements in the at least one direction, for each respective pair there was at least one respective light-emitting element in the epitaxial monolithic layer that was positioned between the pair of light-emitting elements in the epitaxial monolithic layer in the at least one direction and that is not positioned between them in the non-monolithic array.   
     
     
         17 . The illumination apparatus of  claim 16 , wherein the illumination apparatus comprises a support substrate different to the growth substrate, and the non-monolithic array of light-emitting elements is arranged on the support substrate. 
     
     
         18 . The illumination apparatus of  claim 16 , wherein the spacing of the light emitting elements in at least one direction is greater than twice the width of the respective light emitting elements in that direction. 
     
     
         19 . The illumination apparatus of  claim 16 , wherein at least one characteristic of the epitaxial monolithic layer varied across the epitaxial monolithic layer on the growth substrate. 
     
     
         20 . The illumination apparatus of  claim 19 , wherein the at least one characteristic comprises emission wavelength and/or forward voltage. 
     
     
         21 . The illumination apparatus of  claim 16 , wherein the removed light emitting elements comprise gallium nitride epitaxial layers. 
     
     
         22 . The illumination apparatus of  claim 21 , wherein the removal comprised dissociation of gallium nitride material. 
     
     
         23 . The illumination apparatus of  claim 16 , wherein the illumination apparatus comprises a quantum well structure and a doped layer, and
 the quantum well structure is arranged between the doped layer and the support substrate.   
     
     
         24 . The illumination apparatus of  claim 16 , further comprising drive circuitry arranged to drive the light-emitting elements in the non-monolithic array. 
     
     
         25 . A display apparatus comprising the illumination apparatus of  claim 16 .