| 摘要 |
PURPOSE:To improve and uniformize the light emission output of LEDs by specifying the surface roughness of the common electrode on the rear surface of an LED array, thereby decreasing the combined resistance of the common electrode and a conductive adhesive and decreasing the fluctuation thereof. CONSTITUTION:The common electrode is provided on the rear surface of the LED array. This common electrode and the electrodes provided on a substrate are connected and fixed by the conductive adhesive. The surface roughness of the common electrode is specified to <=3mum. Namely, the resistance value increases and fluctuations increase drastically as well with 3mum surface roughness as a boundary in the relation between the surface roughness of the common electrode and the combined resistance of the common electrode and the conductive adhesive. Then, the contact between the common electrode and the conductive adhesive is improved and the less fluctuating contact is obtd. with the low resistance if the surface roughness of the common electrode is confined to <=3mum. The lowering of the resistance by using a metallic plate in place of eliminating the ruggedness of the common electrode is equally well. |
