Light-emitting device having light-emitting elements

Abstract

A light-emitting device operating on a high drive voltage and a small drive current. LEDs ( 1 ) are two-dimensionally formed on an insulating substrate ( 10 ) of e.g., sapphire monolithically and connected in series to form an LED array. Two such LED arrays are connected to electrodes ( 32 ) in inverse parallel. Air-bridge wiring ( 28 ) is formed between the LEDs ( 1 ) and between the LEDs ( 1 ) and electrodes ( 32 ). The LED arrays are arranged zigzag to form a plurality of LEDs ( 1 ) to produce a high drive voltage and a small drive current. Two LED arrays are connected in inverse parallel, and therefore an AC power supply can be used as the power supply.

1 . A light-emitting diode, comprising:
 a first first type GaN-based semiconductor layer;   a first second type GaN-based semiconductor layer;   a first light-emitting layer disposed between the first first type GaN-based semiconductor layer and the first second type GaN-based semiconductor layer;   a first metal electrode layer arranged on the first first type GaN-based semiconductor layer;   a second metal electrode layer arranged on the first second type GaN-based semiconductor layer;   a first vacuum-evaporated metal layer arranged on the first metal electrode layer or the second metal electrode layer; and   a plating metal layer arranged on the first vacuum-evaporated metal layer,   wherein the plating metal layer is deposited over the entire surface of the first vacuum-evaporated metal layer,   wherein the plating metal layer is thicker than the first vacuum-evaporated metal layer, and   wherein the first first type GaN-based semiconductor layer is arranged on a substrate.   
     
     
         2 . The light-emitting diode of  claim 1 , wherein a bottom area of the plating metal layer is larger than a contact area between the first metal electrode layer or second metal electrode layer and the plating metal layer. 
     
     
         3 . The light-emitting diode of  claim 1 , further comprising a first metal layer disposed between the first first type GaN-based semiconductor layer and the first metal electrode layer or between the first first type GaN-based semiconductor layer and the second metal electrode layer. 
     
     
         4 . The light-emitting diode of  claim 3 , further comprising a second metal layer disposed between the first vacuum-evaporated metal layer and the first metal electrode layer or the second metal electrode layer. 
     
     
         5 . The light-emitting diode of  claim 1 , wherein the first vacuum-evaporated metal layer and the plating metal layer comprise the same material. 
     
     
         6 . The light-emitting diode of  claim 1 , wherein the first metal electrode layer comprises Au or Al, the second metal electrode layer comprises Au or Al, and the first metal electrode layer and the second metal electrode layer do not comprise the same material. 
     
     
         7 . The light emitting diode of  claim 1 , further comprising;
 a second first type GaN-based semiconductor layer;   a second second type GaN-based semiconductor layer; and   a second light emitting layer disposed between the second first type GaN-based semiconductor layer and the second second type GaN-based semiconductor layer,   wherein the second first type GaN-based semiconductor layer is arranged on the substrate.   
     
     
         8 . The light emitting diode of  claim 7 , wherein the plating metal layer connects the first first type semiconductor layer and the second first type semiconductor layer on the substrate. 
     
     
         9 . The light emitting diode of  claim 8 , wherein the first first type semiconductor layer and the second first type semiconductor layer are connected in parallel. 
     
     
         10 . The light emitting diode of  claim 8 , further comprising:
 a third metal electrode layer arranged on the second first type GaN-based semiconductor layer;   a fourth metal electrode layer arranged on the second second type GaN-based semiconductor layer; and   a second vacuum-evaporated metal layer arranged on the third metal electrode layer or the fourth metal electrode layer,   wherein the plating metal layer is deposited over the entire surface of the second vacuum-evaporated metal layer.   
     
     
         11 . The light emitting diode of  claim 7 , wherein the plating metal layer electrically connects the first first type semiconductor layer and the second second type semiconductor layer. 
     
     
         12 . The light emitting diode of  claim 11 , wherein the first first type semiconductor layer and the second second type semiconductor layer are connected in series. 
     
     
         13 . The light emitting diode of  claim 1 , further comprising:
 a plurality of light emitting layers separated from each other on the substrate.   
     
     
         14 . The light emitting diode of  claim 13 , further comprising:
 a plurality of light emitting elements each comprising the a light emitting layer of the plurality of light emitting layers, the plurality of light emitting elements being connected in series.   
     
     
         15 . The light emitting diode of  claim 14 , further comprising a plurality of first metal electrode layers and a plurality of second metal electrode layers,
 wherein each light emitting element of the plurality of light emitting elements comprises a first metal electrode layer of the plurality of first metal electrode layers and a second metal electrode layer of the plurality of second metal electrode layers.   
     
     
         16 . The light emitting diode of  claim 15 , wherein a bottom area of the plating metal layer is larger than a contact area between each first metal electrode layer of the plurality of first metal electrode layers or each second metal electrode layer of the plurality of second metal electrode layers and the plating layer. 
     
     
         17 . A light-emitting diode, comprising:
 a first first type GaN-based semiconductor layer;   a first second type GaN-based semiconductor layer;   a first light-emitting layer disposed between the first first type GaN-based semiconductor layer and the first second type GaN-based semiconductor layer;   a first metal electrode layer arranged on the first first type GaN-based semiconductor layer;   a second metal electrode layer arranged on the first second type GaN-based semiconductor layer;   a vacuum-evaporated metal layer arranged on the first metal electrode layer or the second metal electrode layer; and   a plating metal layer arranged on the vacuum-evaporated metal layer,   wherein the vacuum-evaporated metal layer and the plating metal layer comprise the same material,   wherein the plating metal layer is thicker than the vacuum-evaporated metal layer, and   wherein the first first type GaN-based semiconductor layer is arranged on a substrate.   
     
     
         18 . The light-emitting diode of  claim 17 , wherein the plating metal layer directly contacts the vacuum-evaporated metal layer.