Displacement detector
First Claim
1. A displacement detector comprising:
- a scale having a diffraction grating; and
a detection head, which is arranged being capable of relatively moving with respect to the scale, emitting interference light to the scale and receiving diffracted light sent from the scale, the detection head including;
a light source emitting the interference light;
a light dividing section for dividing light, which has been sent from the light source, into two beams of light;
an optical element, which is arranged for each of the two beams of light sent from the light dividing section, for reflecting the beam of light sent from the light dividing section and making the beam of light be incident upon the scale as incident light; and
a retroreflector, which is arranged for each of the beams of diffracted light generated when the two beams of light incident upon the scale are diffracted by the diffraction grating, for retroreflecting the diffracted light and making the light be incident upon the scale as retroreflected light, wherein the incident light and the retroreflected light are incident in a direction perpendicular to a diffraction grating groove, and an angle formed between the incident light and the normal line vector of the scale is larger than an angle formed between the retroreflected light and the normal line vector of the scale.
1 Assignment
0 Petitions
Accused Products
Abstract
The displacement detector includes: a light source 140; a beam splitter 170 for dividing the light, which is sent from the light source 140, into two beams of light; reflection mirrors 181, 182 provided for the two beams of light sent from the beam splitter 170, for reflecting these two beams of light and making them incident upon a scale 110; and corner cubes 191, 192 provided for the beams of diffracted light, which are generated when two beams of light incident upon the scale 110 are diffracted by the diffraction grating 111, wherein the corner cubes 191, 192 retroreflect the diffracted light and make the light incident upon the scale as retroreflected light. The incident angle to grating groove formed between the incident light and the normal line vector of the scale is larger than the diffraction angle formed between the retroreflected light and the normal line vector of the scale.
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Citations
5 Claims
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1. A displacement detector comprising:
- a scale having a diffraction grating; and
a detection head, which is arranged being capable of relatively moving with respect to the scale, emitting interference light to the scale and receiving diffracted light sent from the scale,the detection head including;
a light source emitting the interference light;
a light dividing section for dividing light, which has been sent from the light source, into two beams of light;
an optical element, which is arranged for each of the two beams of light sent from the light dividing section, for reflecting the beam of light sent from the light dividing section and making the beam of light be incident upon the scale as incident light; and
a retroreflector, which is arranged for each of the beams of diffracted light generated when the two beams of light incident upon the scale are diffracted by the diffraction grating, for retroreflecting the diffracted light and making the light be incident upon the scale as retroreflected light, wherein the incident light and the retroreflected light are incident in a direction perpendicular to a diffraction grating groove, and an angle formed between the incident light and the normal line vector of the scale is larger than an angle formed between the retroreflected light and the normal line vector of the scale. - View Dependent Claims (2, 3, 4, 5)
- a scale having a diffraction grating; and
Specification