FORM MEASURING APPARATUS, STRUCTURE MANUFACTURING SYSTEM, SCANNING APPARATUS, METHOD FOR MEASURING FORM, METHOD FOR MANUFACTURING STRUCTURE, AND NON-TRANSITORY COMPUTER READABLE MEDIUM STORING PROGRAM FOR MEASURING FORM

• US 20130321823A1
• Filed: 03/05/2013
• Published: 12/05/2013
• Est. Priority Date: 03/06/2012
• Status: Active Grant

• Current Assignee: Nikon Corporation
• Original Assignee: Nikon Corporation
• Inventors: TAKAHASHI, Akira
• Granted Patent: US 9,146,096 B2
• Time in Patent Office: Days
• US Class Current: 356/601
• CPC Class Codes: G01B 11/24 for measuring contours or curvatures
• CPC Class Codes: G01B 11/2513 with several lines being projected in more than one direction, e.g. grids, patterns
• CPC Class Codes: G02B 26/10 Scanning systems

Abstract

There is provided a form measuring apparatus including: a light generator configured to generate a light; a projector configured to scan the measuring object with the light by changing an irradiation direction of the light generated by the light generator; a controller configured to control the light generator to periodically change an intensity of the light generated by the light generator, and to change an amplitude of the intensity change of the generated light according to the irradiation direction; an imager configured to take an image of the measuring object; and a measuring portion configured to calculate the three-dimensional form of the measuring object based on the image of the measuring object.

Claims

1. A form measuring apparatus configured to measure a three-dimensional form of a measuring object, comprising:

a light generator configured to generate a light;

a projector configured to scan the measuring object with the light by changing an irradiation direction of the light generated by the light generator;

a controller configured to control the light generator to periodically change an intensity of the light generated by the light generator, and to change an amplitude of the intensity change of the generated light according to the irradiation direction;

an imager configured to take an image of the measuring object; and

a measuring portion configured to calculate the three-dimensional form of the measuring object based on the image of the measuring object.

2. The form measuring apparatus according to claim 1, wherein the imager includes an imaging element configured to take the image, formed on a light receiving plane, of the measuring object;

and

under a condition that the measuring object is a flat surface conjugate to the light receiving plane, the controller is configured to control the light generator to change the amplitude of the intensity change of the light generated by the light generator according to a direction of scanning with the light by the projector, so as to image a grating pattern with equal difference in light intensity between bright part and dark part in the image taken by the imaging element through exposure over a predetermined period of time.

3. The form measuring apparatus according to claim 1, wherein the imager includes an imaging element, and an imaging optical system which is configured to form the image of the measuring object to the imaging element;

and

the controller is configured to control the light generator to change the amplitude of the intensity change of the light generated by the light generator according to optical conditions of the imaging optical system.

4. The form measuring apparatus according to claim 1, wherein the controller is configured to generate a control signal which is supplied to the light generator to modulate the intensity of the light generated by the light generator in proportion to the intensity of the control signal, and

the controller is further configured to change an amplitude of the control signal supplied to the light generator according to the irradiation direction.

5. The form measuring apparatus according to claim 1, wherein the controller is configured to control the light generator to change a period of the intensity change of the light generated by the light generator according to the irradiation direction.

6. The form measuring apparatus according to claim 1, wherein the projector includes a deflector configured to change the irradiation direction of the light toward the measuring object with a constant period.

7. The form measuring apparatus according to claim 6, wherein the deflector is a reflecting member of a simple harmonic motion type.

8. The form measuring apparatus according to claim 5, wherein the controller is configured to control the light generator to change the period of the intensity change of the light generated by the light generator based on an elapsed time from a point of time at which the projector deflected the irradiation direction of the light toward the measuring object to a predetermined direction.

9. The form measuring apparatus according to claim 1, wherein an exposure time of the imager is setup synchronized with the projector.

10. The form measuring apparatus according to claim 5, wherein the imager includes an imaging element, and an imaging optical system which is configured to form the image of the measuring object to the imaging element;

and

the controller is configured to control the light generator to change the period of the intensity change of the light generated by the light generator according to optical conditions of the imaging optical system.

11. The form measuring apparatus according to claim 5, wherein the controller is configured to control the light generator to change the period of the intensity change of the light generated by the light generator, so as to lengthen the period of the intensity change of the irradiated light according to the direction of scanning the measuring object in an end area rather than a central area on the measuring object of which image is taken by the imager.

12. The form measuring apparatus according to claim 5, wherein the imager includes an imaging element which is configured to take the image, formed on a light receiving plane, of the measuring object;

and

under a condition that the measuring object is a flat surface conjugate to the light receiving plane, the controller is configured to control the light generator to change the period of the intensity change of the light generated by the light generator according to a direction of scanning with the light by the projector, so as to image a grating pattern with equal difference in light intensity between bright part and dark part in the image taken by the imager through exposure over a predetermined period of time.

13. The form measuring apparatus according to claim 5, wherein the controller is configured to control the light generator to change the period of the intensity change of the light generated by the light generator in inverse proportion to the distance between the projector and the area irradiated with the light on the measuring object.

14. The form measuring apparatus according to claim 5, wherein the controller is configured to generate a control signal which is supplied to the light generator to modulate the intensity of the light generated by the light generator in proportion to the intensity of the control signal, and

the controller is further configured to change a period of the control signal supplied to the light generator according to the irradiation direction.

15. The form measuring apparatus according to claim 1, further comprising a detector which is configured to detect the irradiation direction of the light toward the measuring object,

wherein the controller is configured to control the light generator based on the irradiation direction detected by the detector.

16. The form measuring apparatus according to claim 15, wherein the detector is configured to detect a signal indicating that the irradiation direction of the light is a predetermined direction;

and

the controller is configured to control the light generator based on the signal detected by the detector, so that the intensity of the light generated by the light generator is synchronized with the irradiation direction of the light from the projector.

17. The form measuring apparatus according to claim 1, further comprising a storage configured to store information related to the intensity of the light generated by the light generator with associating with the irradiation direction of the light toward the measuring object,

wherein the controller is configured to control the light generator based on the information stored in the storage.

18. The form measuring apparatus according to claim 1, wherein the light generator is configured to generate the light of which intensity changes sinusoidally.

19. The form measuring apparatus according to claim 1, wherein the projector is configured to form a light amount distribution in a shape of a grating pattern on the measuring object by scanning with the light from the light generator over the measuring object;

and

the controller is configured to control the intensity of the light generated by the light generator to change initial phase of the grating pattern formed on the measuring object.

20. A structure manufacturing system comprising:

a design apparatus configured to create design information related to a form of a structure;

a forming apparatus configured to form the structure based on the design information;

the form measuring apparatus according to claim 1; and

an inspection device configured to compare form information obtained by the form measuring apparatus with the design information.

21. A form measuring apparatus configured to measure a three-dimensional form of a measuring object, comprising:

a light generator configured to generate a light;

a projector configured to scan the measuring object with the light by changing an irradiation direction of the light generated by the light generator;

a controller configured to control the light generator to sinusoidally change intensity of the light generated by the light generator, and to change a period of the intensity change of the generated light according to the irradiation direction;

an imager configured to take an image of the measuring object; and

a measuring portion configured to calculate the three-dimensional form of the measuring object based on the image of the measuring object.

22. A scanner configured to scan with a light a measuring object of which three-dimensional form is to be measured, comprising:

a light generator configured to generate the light;

a projector configured to scan the measuring object with the light by changing an irradiation direction of the light generated by the light generator; and

a controller configured to control the light generator to change an amplitude of an intensity change of the light generated by the light generator according to the irradiation direction.

23. The scanner according to claim 22, wherein the controller is configured to control the light generator to change a period of the intensity change of the light generated by the light generator according to the irradiation direction.

31. The form measuring method according to claim 23, wherein upon modulating the period of the intensity change of the generated light, the period of the intensity change of the generated light is modulated based on properties of an optical system which is configured to cause an imaging element to form the image of the measuring object.

24. A form measuring method for measuring three-dimensional form of a measuring object, comprising:

generating a light;

scanning the measuring object with the light by changing an irradiation direction of the generated light;

modulating an intensity of the generated light periodically, and modulating an amplitude of an intensity change of the generated light according to the irradiation direction;

taking an image of the measuring object in synchronization with scanning the measuring object with the light; and

calculating the three-dimensional form of the measuring object based on the taken image.

25. The form measuring method according to claim 24, wherein upon modulating the amplitude of the intensity change of the generated light, the amplitude of the intensity of the generated light is modulated, so as to image a grating pattern with equal difference in light intensity between bright part and dark part in the image, taken by the imaging element, of the measuring object, under a condition that the measuring object is a flat surface conjugate to a light receiving plane of an imaging element which takes the image of the measuring object.

26. The form measuring method according to claim 24, wherein upon modulating the amplitude of the intensity change of the generated light, the amplitude of the intensity of the generated light is modulated based on properties of an optical system which is configured to cause an imaging element to form the image of the measuring object.

27. The form measuring method according to claim 24, wherein upon modulating the amplitude of the intensity change of the generated light, a control signal is generated to modulate the intensity of the generated light in proportion to the intensity of the control signal, and an amplitude of the intensity change of the generated control signal is modulated according to the irradiation direction.

28. The form measuring method according to claim 24, further comprising:

modulating a period of the intensity change of the generated light according to the irradiation direction.

29. The form measuring method according to claim 28, wherein upon modulating the period of the intensity change of the generated light, the period of the intensity change of the generated light is modulated based on an elapsed time from a point of time of deflecting the irradiation direction of the generated light toward the measuring object to a predetermined direction.

30. The form measuring method according to claim 29, wherein an exposure time for taking the image is setup synchronized with scanning the measuring object with the light.

32. The form measuring method according to claim 28, wherein upon modulating the period of the intensity change of the generated light, the period of the intensity change of the generated light is lengthened in an end area rather than a central area of taking the image of the measuring object.

33. The form measuring method according to claim 28, wherein upon modulating the period of the intensity change of the generated light, the period of the intensity change of the generated light is modulated, so as to image a grating pattern with equal difference in light intensity between a bright part and a dark part in the taken image of the measuring object, under a condition that the measuring object is a flat surface conjugate to a light receiving plane of an imaging element which is configured to take the image of the measuring object.

34. The form measuring method according to claim 28, wherein upon modulating the period of the intensity change of the generated light, the period of the intensity change of the generated light is modulated in inverse proportion to the distance between a projector which is configured to change an irradiation direction of the generated light toward the measuring object, and a position irradiated with the light on the measuring object.

35. The form measuring method according to claim 28, wherein upon modulating the period of the intensity change of the generated light, a control signal is generated to modulate the intensity of the generated light in proportion to the intensity of the control signal, and the period of the intensity change of the generated control signal is modulated according to the irradiation direction.

36. The form measuring method according to claim 24, further comprising:

detecting a changing irradiation direction of the light toward the measuring object,

wherein upon modulating the period of the intensity change of the generated light, the period of the intensity change of the generated light is modulated based on the detected irradiation direction.

37. The form measuring method according to claim 36, wherein upon detecting the changing irradiation direction of the light toward the measuring object, a signal indicating that the changing irradiation direction of the light is a predetermined direction is detected;

and upon modulating the period of the intensity change of the generated light, the intensity change of the light is modulated based on the detected signal, so as to synchronize the irradiation direction of the light with the intensity of the generated light.

38. The form measuring method according to claim 24, further comprising:

storing information related to the intensity of the generated light with associating with the changing irradiation direction of the light toward the measuring object,

wherein upon modulating the period of the intensity change of the generated light, the intensity change of the light is modulated based on the stored information.

39. The form measuring method according to claim 24, wherein upon scanning the measuring object with the light, the measuring object is scanned with the generated light to form a light amount distribution in a shape of a grating pattern on the measuring object;

and

upon modulating the period of the intensity change of the generated light, the intensity of the generated light is modulated to change initial phase of the grating pattern formed on the measuring object.

40. A structure manufacturing method comprising:

creating design information related to a form of a structure;

manufacturing the structure based on the design information;

measuring the form of the manufactured structure by using the form measuring method as defined in claim 24; and

comparing the obtained form information with the design information.

41. The structure manufacturing method according to claim 40, further comprising:

carrying out reprocessing of the structure based on a result of comparing the form information with the design information.

42. The structure manufacturing method according to claim 41, wherein upon carrying out the reprocessing, manufacturing the structure is carried out over again.

43. A non-temporary computer-readable medium storing a form measuring program configured to cause a computer as a form measuring apparatus to carry out operations comprising:

generating light, via a light generator of the form measuring apparatus;

scanning a measuring object with the light by changing irradiation direction of the generated light, via a projector of the form measuring apparatus;

controlling the light generator, via a controller of the form measuring apparatus, to periodically modulate an intensity of the light generated via the light generator, and to modulate an amplitude of the intensity change of the generated light according to the irradiation direction;

taking an image of the measuring object scanned via the projector with the light, via an imager of the form measuring apparatus; and

measuring form of the measuring object based on the image, obtained via the imager, of the measuring object, via a measuring portion of the form measuring apparatus.

44. The computer-readable medium according to claim 43, wherein upon controlling the light generator via the controller, the controller controls the light generator to modulate a period of the intensity change of the light generated via the light generator, according to the irradiation direction.