Abstract: A displacement calculation device 30 calculates a displacement based on two or more displacement detection signals differing in phase. The displacement calculating device 30 includes a detected displacement calculation unit 32 calculating a detected displacement based on the displacement detection signals, a signal analysis unit 33 calculating an amplitude error, a vibration center error, and a phase error between the displacement detection signals and a reference signal, a periodic displacement error calculation unit 34 calculating a periodic displacement error and a period of the displacement error based on the errors calculated by the signal analysis unit 33, and a displacement correction unit 35 correcting the detected displacement calculated by the detected displacement calculation unit 32, based on the displacement error and its period calculated by the periodic displacement error calculation unit 34, and outputting a corrected calibrated displacement.

Abstract: A displacement detection device is capable of stably and accurately detecting an amount of displacement. A polarization maintaining fiber has a length not to be equal to a length obtained by dividing, a product of an integral multiple of twice a length of a resonator times a refractive index of the resonator and a beat length obtained from a difference between propagation constants of two polarization modes, by a wavelength of the light source, is selected from a range including a length equal to the above length. The polarization maintaining fiber includes multiple polarization maintaining fibers fitted to each other by removable connectors.

Abstract: A displacement detection device is capable of stably and accurately detecting an amount of displacement. A polarization maintaining fiber has a length not to be equal to a length obtained by dividing, a product of an integral multiple of twice a length of a resonator times a refractive index of the resonator and a beat length obtained from a difference between propagation constants of two polarization modes, by a wavelength of the light source, is selected from a range including a length equal to the above length. The polarization maintaining fiber includes multiple polarization maintaining fibers fitted to each other by removable connectors.

Abstract: A displacement detecting device includes a first diffraction grating, a light source, a displacement detecting unit, and a light receiving unit. The displacement detecting unit includes a light flux dividing unit, a second diffraction grating, and a reference reflecting member. An incident angle of a first light flux to the first diffraction grating, a diffraction angle of the first diffraction grating, an incident angle of the first light flux to the second diffraction grating, and a diffraction angle of the second diffraction grating are angles at which a displacement amount in an optical path length of the first light flux from the light flux dividing unit to the first diffraction grating and a displacement amount in an optical path length of the first light flux from the first diffraction grating to the second diffraction grating become equal in a case where a measured member is displaced in a direction orthogonal to a measured surface.

Abstract: A displacement detecting device includes a first diffraction grating, a light source, a displacement detecting unit, and a light receiving unit. The displacement detecting unit includes a light flux dividing unit, a second diffraction grating, and a reference reflecting member. An incident angle of a first light flux to the first diffraction grating, a diffraction angle of the first diffraction grating, an incident angle of the first light flux to the second diffraction grating, and a diffraction angle of the second diffraction grating are angles at which a displacement amount in an optical path length of the first light flux from the light flux dividing unit to the first diffraction grating and a displacement amount in an optical path length of the first light flux from the first diffraction grating to the second diffraction grating become equal in a case where a measured member is displaced in a direction orthogonal to a measured surface.

Abstract: A displacement detection apparatus capable of stably and accurately detecting the amount of displacement. The length of a polarization maintaining fiber for transmitting the light from a light source to a displacement detector is set not to be equal to a length obtained by dividing, by the wavelength of the light source, a product of an even integral multiple of a length, which is obtained by multiplying twice the length of a resonator by the refractive index of the resonator, and a beat length obtained by a difference between the propagation constants of two polarization modes. Alternatively, the length of the polarization maintaining fiber is set to be larger than a length, which is obtained by dividing, by the wavelength of the light source, a product of a coherence length and a beat length obtained from a difference between the propagation constants of two polarization modes.

Abstract: A scale has marks whose pitch interval changes along a measurement direction in a manner that can be approximated to a quadratic or higher-order polynomial. A comparing unit calculates a difference between first relative position information and second relative position information per unit displacement in a position where a first displacement detecting unit is arranged. Then, an absolute position computing unit computes an absolute position in the measurement direction with respect to the scale based on absolute position information and the relative position information of at least one of the first relative position information and the second relative position information, and outputs the absolute position.

Abstract: 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.

Abstract: A displacement detection apparatus capable of stably and accurately detecting the amount of displacement. The length of a polarization maintaining fiber for transmitting the light from a light source to a displacement detector is set not to be equal to a length obtained by dividing, by the wavelength of the light source, a product of an even integral multiple of a length, which is obtained by multiplying twice the length of a resonator by the refractive index of the resonator, and a beat length obtained by a difference between the propagation constants of two polarization modes. Alternatively, the length of the polarization maintaining fiber is set to be larger than a length, which is obtained by dividing, by the wavelength of the light source, a product of a coherence length and a beat length obtained from a difference between the propagation constants of two polarization modes.

Abstract: A first light flux serving as object light is caused to enter a member to be measured, and reflected light thereof is caused to enter again the member to be measured after being diffracted by a first diffraction grating. Then, the second-time reflected light of the first light flux by the member to be measured is diffracted by a second diffraction grating. By diffracting the first light flux by the second diffraction grating, a change of the optical path length caused by tilting of the member to be measured is cancelled.

Abstract: A first light flux serving as object light is caused to enter a member to be measured, and reflected light thereof is caused to enter again the member to be measured after being diffracted by a first diffraction grating. Then, the second-time reflected light of the first light flux by the member to be measured is diffracted by a second diffraction grating. By diffracting the first light flux by the second diffraction grating, a change of the optical path length caused by tilting of the member to be measured is cancelled.

Abstract: 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.

Abstract: A displacement detecting device includes a light source, a beam splitting section, a diffraction grating, a reflecting section, a beam combining section, a light receiving section, and a relative position information output section. The diffraction grating is adapted to diffract a first beam reflected by a surface-to-be-measured of a member-to-be-measured, and cause the diffracted first beam to be incident again on the surface-to-be-measured. The reflecting section is adapted to reflect a second beam split by the beam splitting section to the beam splitting section. The light receiving section is adapted to receive interfering light of the first beam and the second beam. The relative position information output section is adapted to output displacement information of the surface-to-be-measured in the height direction based on intensity of the received interfering light.

Abstract: A scale has marks whose pitch interval changes along a measurement direction in a manner that can be approximated to a quadratic or higher-order polynomial. A comparing unit calculates a difference between first relative position information and second relative position information per unit displacement in a position where a first displacement detecting unit is arranged. Then, an absolute position computing unit computes an absolute position in the measurement direction with respect to the scale based on absolute position information and the relative position information of at least one of the first relative position information and the second relative position information, and outputs the absolute position.

Abstract: A displacement detecting device has a diffraction grating, grating interferometers, and relative position information output sections. The grating interferometers have a light source, reflectors, a beam splitter, and light receiving sections. The reflectors reflect 1st-order diffracted lights diffracted by the diffraction grating, and cause the reflected 1st-order diffracted lights to be incident at a position substantially identical to the position at which the light from the light source is irradiated. Furthermore, the reflectors cause the 1st-order diffracted lights to be incident on the diffraction grating at an angle different to either the incidence angle of the light from the light source incident on the diffraction grating or the angle at which the 1st-order diffracted lights are transmitted through or reflected by the diffraction grating.

Abstract: A displacement detecting device includes a light source, a beam splitting section, a diffraction grating, a reflecting section, a beam combining section, a light receiving section, and a relative position information output section. The diffraction grating is adapted to diffract a first beam reflected by a surface-to-be-measured of a member-to-be-measured, and cause the diffracted first beam to be incident again on the surface-to-be-measured. The reflecting section is adapted to reflect a second beam split by the beam splitting section to the beam splitting section. The light receiving section is adapted to receive interfering light of the first beam and the second beam. The relative position information output section is adapted to output displacement information of the surface-to-be-measured in the height direction based on intensity of the received interfering light.

Abstract: A displacement detecting device comprises: a light source, a first beam splitter adapted to split the light emitted from the light source into a first beam and a second beam, a reflecting member adapted to reflect the first beam, an objective lens adapted to condense the second beam on a surface-to-be-measured, a first light receiving section adapted to receive interference light of the reflected first beam and the reflected second beam, a relative position information output section adapted to output relative position information in height direction of the surface-to-be-measured, a second beam splitter adapted to extract a part of the reflected second beam, an astigmatism generator adapted to generate astigmatism in the extracted second beam, a second light receiving section adapted to receive the second beam having astigmatism, and an absolute position information output section adapted to generate absolute position information in height direction of the surface-to-be-measured.

Abstract: A displacement detecting device includes a non-contact sensor having a light source, an objective lens focusing output light from the light source onto a measurement surface, and a light receiving element detecting displacement information based on a focal length of the objective lens by using reflected light from the measurement surface; a control unit adjusting the focal length based on the displacement information; a displacement-amount measuring unit having a linear scale attached to the objective lens with a link member therebetween and measuring an amount of displacement of the linear scale when the focal length is adjusted. A light adjustment member is disposed between the light source and the objective lens or between the objective lens and the light receiving element and has an aperture section transmitting the output and/or reflected light therethrough and a light blocking section that blocks a specific light component of the output and/or reflected light.

Abstract: A displacement detecting device comprises: a light source, a first beam splitter adapted to split the light emitted from the light source into a first beam and a second beam, a reflecting member adapted to reflect the first beam, an objective lens adapted to condense the second beam on a surface-to-be-measured, a first light receiving section adapted to receive interference light of the reflected first beam and the reflected second beam, a relative position information output section adapted to output relative position information in height direction of the surface-to-be-measured, a second beam splitter adapted to extract a part of the reflected second beam, an astigmatism generator adapted to generate astigmatism in the extracted second beam, a second light receiving section adapted to receive the second beam having astigmatism, and an absolute position information output section adapted to generate absolute position information in height direction of the surface-to-be-measured.

Abstract: A displacement detecting device has a diffraction grating, grating interferometers, and relative position information output sections. The grating interferometers have a light source, reflectors, a beam splitter, and light receiving sections. The reflectors reflect 1st-order diffracted lights diffracted by the diffraction grating, and cause the reflected 1st-order diffracted lights to be incident at a position substantially identical to the position at which the light from the light source is irradiated. Furthermore, the reflectors cause the 1st-order diffracted lights to be incident on the diffraction grating at an angle different to either the incidence angle of the light from the light source incident on the diffraction grating or the angle at which the 1st-order diffracted lights are transmitted through or reflected by the diffraction grating.