| 摘要 |
A displacement detecting device includes a light source that performs irradiation with light, a light-beam splitting section, a reflection/transmission section, a phase plate, a transmission-type diffraction grating, a light-beam combining section, a light-receiving section, and a relative position information output unit. The reflection/transmission section transmits or reflects a first light beam, and causes the beam to enter a member to be measured. Furthermore, the reflection/transmission section guides the first light beam to a specific position of the member to be measured in the case where the member to be measured is in a reference position. Moreover, an optical path of the first light beam reflected by the member to be measured again overlaps with an optical path of the first light beam reflected at a specific position of the member to be measured. |
| 主权项 |
1. A displacement detecting device, comprising:
a light source that performs irradiation with light; a light-beam splitting section that splits the light emitted from the light source into a first light beam caused to enter a member to be measured and a second light beam serving as a reference light; a reflection/transmission section that transmits or reflects the first light beam in accordance with a polarization direction of the first light beam, and causes the first light beam to enter the member to be measured; a phase plate that changes a polarization direction of the first light beam; a reference reflection section that reflects the second light beam split by the light-beam splitting section; a transmission-type diffraction grating that diffracts the first light beam reflected by a surface to be measured of the member to be measured, and causes the diffracted first light beam to enter the reflection/transmission section again; a light-beam combining section that combines the first light beam diffracted by the diffraction grating with the second light beam reflected by the reference reflection section; a light-receiving section that receives interference light of the first light beam and the second light beam combined by the light-beam combining section; and a relative position information output unit that outputs information on displacement of the surface to be measured in a height direction on the basis of an intensity of interference light received by the light-receiving section, wherein the reflection/transmission section guides the first light beam to a specific position of the member to be measured in a case where the member to be measured is at a reference position, and an optical path of the first light beam reflected again by the member to be measured overlaps with an optical path of the first light beam reflected at the specific position of the member to be measured. |
