| 摘要 |
PURPOSE:To avoid reflection on the emission surface of a laser chip with a simple structure by a method wherein a film made of low light reflection material is formed on the emission surface and the film and the laser beam emission point on the emission surface are distant from each other by more than 50mum. CONSTITUTION:A forward bias is applied between the first and second ohmic electrodes 20 and 21 which are formed on the other main surface of a substrate 14 and on the surface of a cap layer 18 respectively to induce a laser beam from an active layer 16 and the laser beam is outputted from an emission point 0. The chip is bonded to a heat sink 12 electrically and thermally with Au alloy or the like at the first electrode 20 side. A film 22 made of low light- reflective material such as black silicone resin is applied on the emission surface N from a position 50mum apart from the emission point 0 to the heat sink 12. When returning lights P'2(0) and P'0(+1) enter the emission surface N of the laser chip 8, most of the lights are absorbed by a reflection preventing film 10 and, even if a part of the lights are reflected, it is random reflection so that the luminous power of the light returning along the light pass X becomes extremely small. |
