Pastaim, ol i bin yusim ol LED olsem ol lait bilong soim ol samting long ol instramen na ol mita. Bihain, ol i yusim ol LED bilong kain kain kala long ol trefik lait na ol bikpela -eria displei, na dispela i kamapim bikpela ekonomik na sosel benefit. Olsem, wanpela 12-inch retpela trefik lait long Amerika pastaim i bin yusim wanpela longpela-laip, liklik 140-wat inkandesens balb olsem lait sos bilong en, na i save kamapim 2000 lumens bilong waitpela lait. Bihain long em i go insait long wanpela retpela filta, 90% bilong lait i lus, na 200 lumens tasol bilong retpela lait i stap. Insait long nupela lait bilong en, ol i yusim 18 retpela LED, we i yusim 14 wat tasol wantaim ol 'circuit losses', long kamapim wankain lait.
Ol signal lait bilong ol kar em i narapela bikpela samting bilong yusim ol LED lait sos. Long 1987, kantri bilong mi i stat long putim ol brek lait antap long ol kar. Bikos long spit bilong ol LED (nanosecond level), ol draiva bilong ol kar i kam bihain ol i ken kisim toksave long ol kondisen bilong draiv pastaim, na dispela i daunim ol birua long baksait.
Na tu, ol i save yusim ol LED lait long ol retpela, grinpela, na blupela ful-kala displei ausait, ol kisen-stail mini toslait, na ol narapela wok.
Ol waitpela LED: Long ol jenerel lait, ol waitpela lait sos i gutpela moa. Ol i bin kamapim ol waitpela LED long 1998. Ol i wokim ol dispela LED long rot bilong putim wanpela GaN sip na yttrium aluminium garnet (YAG) wantaim.
GaN chip i save givim blupela lait (λp=465nm, Wd=30nm). Ce3+-we i gat YAG fosfora long en, we ol i tanim long bikpela hat, i save givim yelopela lait taim dispela blupela lait i kirapim em, wantaim mak bilong 550nm. Ol i putim blupela LED sabstret insait long wanpela 'reflective cavity' we i gat seip bilong 'bowl-' na ol i karamapim wantaim wanpela liklik hap 'resin' we ol i miksim wantaim YAG, inap olsem 200-500nm tik. Hap bilong blupela lait we LED sabstret i save givim i save go insait long 'phosphor', na narapela blupela lait i save miks wantaim yelo lait we 'phosphor' i save kamapim na kamapim waitpela lait. Long InGaN/YAG waitpela LED, long senisim kemikel komposesen bilong YAG fosfora na stretim tiknes bilong fosfora leia, ol i ken kisim kain kain kala bilong waitpela lait wantaim kala tempereja we i stap namel long 3500-10000K.
Tebol 1 i soim ol kain waitpela LED we i stap nau na ol as tingting bilong ol long givim lait. Tebol i soim tu olsem sampela kain waitpela LED lait sos i save dipen long foapela fosfora: tripela praimeri kala-rare-graun ret, grin, na blupela fosfora-na wanpela yelopela fosfora wantaim wanpela garnet straksa. Tripela-wevlength LED, we i yusim ol inorganik 'ultraviolet chips' wantaim RGB 'phosphors' long karamapim ol waitpela LED, ol i ting bai i gat sans long salim. Tasol, sais bilong ol liklik hap na strong bilong dispela tripela praimeri kala fosfor i liklik tru, na ol i wok long painim yet ol spesifik aplikesen bilong ol.
Nau yet, namba wan prodak we ol i salim em i wanpela blupela 'single-chip LED wantaim YAG yelo 'phosphor', we i gat gutpela lait bilong en inap olsem 25 lumens/watt. YAG em planti taim ol i save kisim long Nichia Koporesen bilong Japan, na prais bilong en i stap klostu long 2000 yuan/kg. Namba tu kain em ol waitpela LED we Sumitomo Electric Industries bilong Japan i wokim na ol i yusim ZnSe olsem samting bilong en, tasol i no gat bikpela lait.
