Optical rotary encoder, servo motor, and actuator
AssigneeHarmonic Drive Systems Inc.
InventorsShintaro UENO, Yoshinori SHIBAHARA, Sadaharu KANAMORI
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Abstract
In this optical rotary encoder, detection tracks of a rotating disc are irradiated with detection light emitted from a light-emitting element. An optical signal obtained via slits in the detection tracks passes through a slit pattern in a fixed slit plate and is received by light-receiving surfaces of a light-receiving element. The slit pattern in the fixed slit plate is formed so as to fit into a range of an effective spot of the detection light. An LED or other light-emitting element that has a small effective spot diameter can be used, which is advantageous in terms of reducing costs and making the device more compact.
Claims6
An optical rotary encoder comprising:
- a rotating disc provided with a plurality of detection tracks that are formed concentrically;
- a light-emitting element that irradiates the detection tracks with detection light;
- a fixed slit plate provided with a slit pattern that allows passage of optical signals obtained from regions irradiated with the detection light in each of the detection tracks;
- and
- a light-receiving element that receives each of the optical signals that have passed through the slit pattern,
- wherein each of the detection tracks is configured from a slit or a reflective zone arranged at regular angular intervals;
- the slit pattern in the fixed slit plate is configured from slit rows, the number of slit rows corresponding to the number of detection tracks;
- the slit rows includes a plurality of first slit rows and a plurality of second slit rows, the first and second slit rows being lined up in the radial direction of the rotating disc;
- the first slit rows have a slit-arrangement-direction length that is shorter than that of the second slit rows;
- and
- the slit pattern is formed so that each of the first slit rows is positioned on both radial-direction sides, the radial direction being a direction in which the slit rows are lined up, and the slit pattern being positioned within an effective irradiation region of the detection light in the fixed slit plate.
Dependencies are inferred from the claim text.