JPH04532B

PURPOSE:To reduce the size of a photointerrupter and to improve resolution by forming a light emitting element and a light receiving element of light- transmissive synthetic resin separately by primary molding. CONSTITUTION:The photointerrupter consists of a light-emission side primary molding part 5, a light-reception side primary molding part 10, and a holder part 14 which stores and holds them in one body. The optical path between the light emitting element 1 and light receiving element 3 is determined by the sizes of a light transmission window 6a on the side of the light-emission side primary molding part 5 and a light transmission window 11a on the side of the light-emission side primary molding part 10. For example, when a shield body moves between the molding parts 5 and 10 as shown by an arrow P or R, the output of the light receiving element 3 varies as shown in a figure and position detection accuracy or resolution L1 corresponding to the width l1 of the light transmission windows 6a and 11a is obtained. For the purpose, the width of the light transmission windows 6a and 11a is reduced to obtain the interrupter with high position accuracy and high resolution.