PURPOSE: To provide an encoder in which a reduction in a cost of a product, a light weight and a compact structure can be realized by simple means.
CONSTITUTION: An encoder has a light emitting element 3 and a light receiving element 4 oppositely disposed above and below a disc 11 to detect a rotating amount of the disc 11 upon reception of presence or absence or an emitted light L from the element 3, and comprises many microlenses 12 formed between the oppositely disposed elements 3 and 4 to convert the light L emitted from the element 3 toward the element 4 into parallel beam light L'. The microlens 12 is formed simultaneously by obtaining the disc 11 by molding a transparent material such as plastic, etc., by injection molding, etc., in a disc state.
JPS6378021A | 1988-04-08 | |||
JP3080325B | ||||
JPS618667A | 1986-01-16 | |||
JPH04115122A | 1992-04-16 |
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