Claims
- 1. A displacement detection apparatus comprising:
- means for irradiating a first beam and a second beam obtained by splitting an irradiation beam onto a second diffraction grating on a substrate;
- synthesizing means for synthesizing a first diffracted beam generated by said second diffraction grating upon irradiation of the first beam, and a second diffracted beam generated by said second diffraction grating upon irradiation of the second beam; and
- means for receiving an interference beam formed by synthesizing the first and second diffracted beams, and converting the interference beam into a signal representing a relative displacement of said substrate,
- wherein said irradiating means comprises a first diffraction grating formed on one of a surface of said substrate on which said second diffraction grating is formed, and another surface of said substrate parallel to the surface on which said second diffraction grating is formed, wherein said substrate is moved relative to said means for irradiating, said synthesizing means, and said means for receiving.
- 2. An apparatus according to claim 1, wherein the first diffracted beam includes +mth-order diffracted light, and the second diffracted beam includes -mth-order diffracted light (where m is a natural number).
- 3. An apparatus according to claim 1, wherein said synthesizing means comprises a third diffraction grating for achieving the synthesis.
- 4. An apparatus according to claim 3, wherein said second diffraction grating is designed to reflectively diffract the first and second beams, and said second diffraction grating is formed on a surface of said substrate facing said third diffraction grating.
- 5. An apparatus according to claim 3, wherein said second diffraction grating is designed to reflectively diffract the first and second beams, and said second diffraction grating is formed on a surface of said substrate opposite to a surface of said substrate facing said third diffraction grating.
- 6. An apparatus according to claim 3, wherein said second diffraction grating is designed to transmit the first and second beams, and said second diffraction grating is formed on a surface of said substrate facing said third diffraction grating.
- 7. An apparatus according to claim 3, wherein said second diffraction grating is designed to transmit the first and second beams, and said second diffraction grating is formed on a surface of said substrate opposite to a surface of said substrate facing said third diffraction grating.
- 8. An apparatus according to claim 1, wherein the first diffracted beam is +1st-order diffracted light, and the second diffracted beam is -1st-order diffracted light.
- 9. A displacement detection apparatus comprising:
- means for irradiating a first beam and a second beam obtained by splitting an irradiation beam onto a second diffraction grating on a substrate;
- synthesizing means for synthesizing a first diffracted beam generated by said second diffraction grating upon irradiation of the first beam, and a second diffracted beam generated by said second diffraction grating upon irradiation of the second beam; and
- means for receiving an interference beam formed by synthesizing the first and second diffracted beams, and converting the interference beam into a signal representing a relative displacement of said substrate,
- wherein said irradiating means comprises a first diffraction grating formed on a surface of said substrate on which said second diffraction grating is formed, or on another surface of said substrate parallel to the surface on which said second diffraction grating is formed, wherein said synthesizing means comprises a third diffraction grating for achieving the synthesis and wherein when grating pitches of said first, second and third diffraction gratings are represented by P1, P2, and P3, the grating pitches substantially satisfy a condition:
- .vertline.P1-P2.vertline..multidot.P3=P1.multidot.P2.
- 10.
- 10. A displacement detection apparatus comprising:
- means for irradiating a first beam and a second beam obtained by splitting an irradiation beam onto a second diffraction grating on a substrate;
- synthesizing means comprising a third diffraction grating for synthesizing a first diffracted beam generated by said second diffraction grating upon irradiation of the first beam, and a second diffracted beam generated by said second diffraction grating upon irradiation of the second beam; and
- means for receiving an interference beam formed by synthesizing the first and second diffracted beams, and converting the interference beam into a signal representing a relative displacement of said substrate,
- wherein said irradiating means comprises a first diffraction grating formed on a surface of said substrate on which said second diffraction grating is formed, or on another surface of said substrate parallel to the surface on which said second diffraction grating is formed,
- wherein said first and second diffraction gratings apply a phase modulated component according to said relative displacement of said substrate to at least one of said first and second diffracted beams and wherein information of said relative displacement of said substrate is obtained through a signal component according to said phase modulated component of said signal converted by said interference beam receiving means,
- wherein said second diffraction grating is designed to reflectively diffract the first and second beams, and said second diffraction grating is formed on a surface of said substrate facing said third diffraction grating,
- wherein when grating pitches of said first, second, and third diffraction gratings are represented by P1, P2, and P3, the grating pitches substantially satisfy a condition:
- .vertline.P1-P2.vertline..multidot.P3=P1.multidot.P2.
- 11.
- 11. A displacement detection apparatus comprising:
- means for irradiating a first beam and a second beam obtained by splitting an irradiation beam onto a second diffraction grating on a substrate;
- synthesizing means comprising a third diffraction grating for synthesizing a first diffracted beam generated by said second diffraction grating upon irradiation of the first beam, and a second diffracted beam generated by said second diffraction grating upon irradiation of the second beam; and
- means for receiving an interference beam formed by synthesizing the first and second diffracted beams, and converting the interference beam into a signal representing a relative displacement of said substrate,
- wherein said irradiating means comprises a first diffraction grating formed on a surface of said substrate on which said second diffraction grating is formed, or on another surface of said substrate parallel to the surface on which said second diffraction grating is formed,
- wherein said first and second diffraction gratings apply a phase modulated component according to said relative displacement of said substrate to at least one of said first and second diffracted beams and wherein information of said relative displacement of said substrate is obtained through a signal component according to said phase modulated component of said signal converted by said interference beam receiving means,
- wherein said second diffraction grating is designed to reflectively diffract the first and second beams, and said second diffraction grating is formed on a surface of said substrate opposite to a surface of said substrate facing said third diffraction grating,
- wherein when grating pitches of said first, second, and third diffraction gratings are represented by P1, P2, and P3, the grating pitches substantially satisfy a condition:
- .vertline.P1-P2.vertline..multidot.P3=P1.multidot.P2.
- 12. A displacement detection apparatus comprising:
- means for irradiating a first beam and a second beam obtained by splitting an irradiation beam onto a second diffraction grating on a substrate;
- synthesizing means comprising a third diffraction grating for synthesizing a first diffracted beam generated by said second diffraction grating upon irradiation of the first beam, and a second diffracted beam generated by said second diffraction grating upon irradiation of the second beam; and
- means for receiving an interference beam formed by synthesizing the first and second diffracted beams, and converting the interference beam into a signal representing a relative displacement of said substrate,
- wherein said irradiating means comprises a first diffraction grating formed on a surface of said substrate on which said second diffraction grating is formed, or on another surface of said substrate parallel to the surface on which said second diffraction grating is formed,
- wherein said first and second diffraction gratings apply a phase modulated component according to said relative displacement of said substrate to at least one of said first and second diffracted beams and wherein information of said relative displacement of said substrate is obtained through a signal component according to said phase modulated component of said signal converted by said interference beam receiving means,
- wherein said second diffraction grating is designed to transmit the first and second beams, and said second diffraction grating is formed on a surface of said substrate facing said third diffraction grating,
- wherein when grating pitches of said first, second, and third diffraction gratings are represented by P1, P2, and P3, the grating pitches substantially satisfy a condition:
- .vertline.P1-P2.vertline..multidot.P3=P1P2.
- 13.
- 13. A displacement detection apparatus comprising:
- means for irradiating a first beam and a second beam obtained by splitting an irradiation beam onto a second diffraction grating on a substrate;
- synthesizing means comprising a third diffraction grating for synthesizing a first diffracted beam generated by said second diffraction grating upon irradiation of the first beam, and a second diffracted beam generated by said second diffraction grating upon irradiation of the second beam; and
- means for receiving an interference beam formed by synthesizing the first and second diffracted beams, and converting the interference beam into a signal representing a relative displacement of said substrate,
- wherein said irradiating means comprises a first diffraction grating formed on a surface of said substrate on which said second diffraction grating is formed, or on another surface of said substrate parallel to the surface on which said second diffraction grating is formed,
- wherein said first and second diffraction gratings apply a phase modulated component according to said relative displacement of said substrate to at least one of said first and second diffracted beams and wherein information of said relative displacement of said substrate is obtained through a signal component according to said phase modulated component of said signal converted by said interference beam receiving means,
- wherein said second diffraction grating is designed to transmit the first and second beams, and said second diffraction grating is formed on a surface of said substrate opposite to a surface of said substrate facing said third diffraction grating,
- wherein when grating pitches of said first, second, and third diffraction gratings are represented by P1, P2, and P3, the grating pitches substantially satisfy a condition:
- .vertline.P1-P2.vertline..multidot.P3=P1.multidot.P2.
- 14. A drive system comprising a displacement detection apparatus comprising:
- means for irradiating a first beam and a second beam obtained by splitting an irradiation beam onto a second diffraction grating on a substrate;
- synthesizing means for synthesizing a first diffracted beam generated by said second diffraction grating upon irradiation of the first beam, and a second diffracted beam generated by said second diffraction grating upon irradiation of the second beam; and
- means for receiving an interference beam formed by synthesizing the first and second diffracted beams, and converting the interference beam into a signal representing a relative displacement of said substrate,
- wherein said irradiating means comprises a first diffraction grating formed on one of a surface of said substrate on which said second diffraction grating is formed, and another surface of said substrate parallel to the surface on which said second diffraction grating is formed, wherein said substrate is moved relative to said means for irradiating, said synthesizing means, and said means for receiving.
- 15. A drive system according to claim 14, wherein the first diffracted beam includes +mth-order diffracted light, and the second diffracted beam includes -mth-order diffracted light (where m is a natural number).
- 16. A drive system according to claim 14, wherein said synthesizing means comprises a third diffraction grating for achieving the synthesis.
- 17. A drive system according to claim 16, wherein said second diffraction grating is designed to reflectively diffract the first and second beams, and said second diffraction grating is formed on a surface of said substrate facing said third diffraction grating.
- 18. A drive system according to claim 16, wherein said second diffraction grating is designed to reflectively diffract the first and second beams, and said second diffraction grating is formed on a surface of said substrate opposite to a surface of said substrate facing said third diffraction grating.
- 19. A drive system according to claim 16, wherein said second diffraction grating is designed to transmit the first and second beams, and said second diffraction grating is formed on a surface of said substrate facing said third diffraction grating.
- 20. A drive system according to claim 16, wherein said second diffraction grating is designed to transmit the first and second beams, and said second diffraction grating is formed on a surface of said substrate opposite to a surface of said substrate facing said third diffraction grating.
- 21. A drive system comprising:
- means for irradiating a first beam and a second beam obtained by splitting an irradiation beam onto a second diffraction grating on a substrate:
- synthesizing means for synthesizing a first diffracted beam generated by said second diffraction grating upon irradiation of the first beam, and a second diffracted beam generated by said second diffraction grating upon irradiation of the second beam; and
- means for receiving an interference beam formed by synthesizing the first and second diffracted beams, and converting the interference beam into a signal representing a relative displacement of said substrate,
- wherein said irradiating means comprises a first diffraction grating formed on a surface of said substrate on which said second diffraction grating is formed, or on another surface of said substrate parallel to the surface on which said second diffraction grating is formed,
- wherein said synthesizing means comprises a third diffraction grating for achieving the synthesis and
- wherein when grating pitches of said first, second, and third diffraction gratings are represented by P1, P2, and P3, the grating pitches substantially satisfy a condition:
- .vertline.P1-P2.vertline..multidot.P3=P1.multidot.P2.
- 22.
- 22. A drive system comprising a displacement detection apparatus comprising:
- means for irradiating a first beam and a second beam obtained by splitting an irradiation beam onto a second diffraction grating on a substrate;
- synthesizing means comprising a third diffraction grating for synthesizing a first diffracted beam generated by said second diffraction grating upon irradiation of the first beam, and a second diffracted beam generated by said second diffraction grating upon irradiation of the second beam; and
- means for receiving an interference beam formed by synthesizing the first and second diffracted beams, and converting the interference beam into a signal representing a relative displacement of said substrate,
- wherein said irradiating means comprises a first diffraction grating formed on a surface of said substrate on which said second diffraction grating is formed, or on another surface of said substrate parallel to the surface on which said second diffraction grating is formed,
- wherein said first and second diffraction gratings apply a phase modulated component according to said relative displacement of said substrate to at least one of said first and second diffracted beams and wherein information of said relative displacement of said substrate is obtained through a signal component according to said phase modulated component of said signal converted by said interference beam receiving means,
- wherein said second diffraction grating is designed to reflectively diffract the first and second beams, and said second diffraction grating is formed on a surface of said substrate facing said third diffraction grating,
- wherein when grating pitches of said first, second, and third diffraction gratings are represented by P1, P2, and P3, the grating pitches substantially satisfy a condition:
- .vertline.P1-P2.vertline..multidot.P3=P1.multidot.P2.
- 23.
- 23. A displacement detecting apparatus comprising:
- light source means for generating a source light beam;
- scale means, said scale means comprising a transparent member, a first diffraction grating provided on a surface of said transparent member, and a second diffraction grating provided on one of said surface and a surface different from said surface, wherein said source light beam from said light source means is divided into a first light beam and a second light beam by said first diffraction grating, and after said first and second light beams traverse said transparent member, said first and second light beams are respectively diffracted by said second diffraction grating to generate a first diffracted light beam and a second diffracted light beam;
- synthesizing means for synthesizing an interference light beam from said first diffracted light beam and said second diffracted light beam; and
- optical receiving means for optically receiving said interference light beam, and generating from said received interference light beam a signal indicating a relative displacement of an object to said transparent member, wherein said scale means is moved relative to said light source means, said synthesizing means, and said optical receiving means.
Priority Claims (1)
Number |
Date |
Country |
Kind |
4-344575 |
Dec 1992 |
JPX |
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Parent Case Info
This application is a continuation, of application Ser. No. 08/169,396 filed Dec. 20, 1993, now abandoned.
US Referenced Citations (18)
Foreign Referenced Citations (6)
Number |
Date |
Country |
0333929 |
Sep 1989 |
EPX |
0463561 |
Jan 1992 |
EPX |
0486050 |
May 1992 |
EPX |
0509979 |
Oct 1992 |
EPX |
1307926 |
Dec 1989 |
JPX |
90-13006 |
Nov 1990 |
WOX |
Continuations (1)
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Number |
Date |
Country |
Parent |
169396 |
Dec 1993 |
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