| 摘要 |
<p>PURPOSE:To make the title device thin without lowering the transmission efficiency of light from a light-emitting element up to a photodetector, to work a metal mold simply and to manufacture the metal mold easily and at low costs. CONSTITUTION:Composite aspherical Fresnel lenses 11, 12 whose parts 11a, 12a coincide with a light-emitting charactsristic and whose outer circumferential parts 11b, 12b coincide with a photodetection characteristic are used as a lighting lens on the front side of a light-emitting element chip 5 in a light-emitting element 1 and as a photodetection lens on the front side of a photodetection chip 9 in a photodetector 2.</p> |
