| 摘要 |
PROBLEM TO BE SOLVED: To solve the problem that, even when a groove defined by two side surfaces vertical to a luminous surface is formed between a light-emitting element and a light-receiving element, the amount of light directly incident on the light-receiving element through a resin layer among the light emitted from the light-emitting element is still large, and that, therefore, the S/N ratio of a reflection light sensor is small.SOLUTION: A light-emitting element 1 and a light-receiving element 2 are mounted on a wiring board 3, which are further encapsulated by a light permeable (visible rays cut) resin layer 4. An ∠-shaped groove 5 is formed whose side surface S1 on the light-emitting element 1 side is perpendicular to a luminous surface and whose side surface S2' of the light-receiving element 2 side is inclined to the light-receiving element 2 side relative to the luminous surface. The incident angle relative to the side surface S2' of light L1 from the light-emitting element 1 passing through the vertical side surface S1 and arriving at the side surface S2' via the air (groove 5) increases. As a result, the amount of light L1 reflected at the side surface S2' becomes large, which results in the amount of light entering the light-receiving element 2 directly from the light-emitting element 1 being reduced. Thus, the S/N ratio of a reflection light sensor can be improved. |
