Surface mount type photo-interrupter and method for manufacturing the same

A method of manufacturing a surface mount type photo-interrupter, the method comprising:

• a step of providing an upper surface of an insulating base with a light emitting element and a light receiving element;
• a step of forming a first terminal electrode for the light emitting element and a second terminal electrode for the light receiving element on at least one of a side surface and a lower surface of the insulating base;
• a first primary mold forming step of pressing primary mold forming die onto the upper surface of the insulating base so as to form a first primary mold made of transparent synthetic resin and covering the light emitting element;
• a second primary mold forming step of pressing a primary mold forming die onto the upper surface of the insulating base so as to form a second primary mold made of transparent synthetic resin and covering the light receiving element;
• and
• a secondary mold forming step of pressing a secondary mold forming die onto the upper surface of the insulating base so as to form a secondary mold made of opaque synthetic resin and fixing the first and the second primary molds integrally;
• wherein, in the secondary mold forming step, the secondary mold is formed with a groove located between the first primary mold and the second primary mold, the groove allowing a detection subject to pass through and being traversed by light propagating from the light emitting element to the light receiving element the secondary mold being also formed with transmission holes through which the light propagates,
• wherein the groove and the transmission holes in the secondary mold are formed by a core, and
• wherein when the secondary mold forming die is pressed onto the insulating base, the secondary mold forming die makes contact with an inclined reflection surface provided at the first primary mold and another inclined reflection surface provided at the second primary mold so as to press both of the first and the second primary molds onto the core.

A method of manufacturing a surface mount type photo-interrupter, the method comprising:

• a step of producing a material substrate including a plurality of regions corresponding to a plurality of insulating substrates;
• a step of providing an upper surface of the material substrate with light emitting elements and light receiving elements corresponding to the respective regions;
• a step of forming, on the material substrate, first terminal electrodes corresponding to the respective light emitting elements at the respective regions and second terminal electrodes corresponding to the respective light receiving elements at the respective regions;
• a first primary mold forming step of pressing a primary mold forming die onto the upper surface of the material substrate so as to form first primary molds made of transparent synthetic resin and covering the respective light emitting elements at the respective regions;
• a second primary mold forming step of pressing a primary mold forming die onto the upper surface of the material substrate so as to form second primary molds made of transparent synthetic resin and covering the respective light receiving elements at the respective regions;
• a secondary mold forming step of pressing a secondary mold forming die onto the upper surface of the material substrate so as to form secondary molds made of opaque synthetic resin and covering the first and the second primary molds integrally at the respective regions;
• and
• a step of cutting the material substrate to isolate the respective regions individually;
• wherein, in the secondary mold forming step, a core integral with the secondary mold forming die is used to form a groove and light transmission holes in each of the secondary molds, the groove being located between the first primary mold and the second primary mold, the groove allowing a detection subject to pass through and being traversed by light propagating from the light emitting element to the light receiving element, and
• wherein when the secondary mold forming die is pressed onto the material substrate, the secondary mold forming die makes contact with inclined reflection surfaces of the first and the second primary molds in each of the regions so as to press both of the first and second primary molds onto the core.