Measurement apparatus for measuring shape of object, system and method for producing article

{
  "publication_number": "US10223575B2",
  "country": "US",
  "kind": "B2",
  "title": "Measurement apparatus for measuring shape of object, system and method for producing article",
  "abstract": "A measurement apparatus includes an optical combining unit configured to optically combine light from a first light source and light from a second light source, a forming unit configured to form pattern light using light from the first light source, a projection optical system configured to project the optically combined light onto an object, an imaging unit configured to image the object on which the pattern light is projected to capture a first image and to image the object illuminated with light from the second light source via the projection optical system to capture a second image, and a processing unit configured to correct the first image using the second image and to obtain information on a shape of the object based on the corrected first image.",
  "claims": [
    "1. A measurement apparatus for measuring a shape of an object, the measurement apparatus comprising: a first light source configured to emit light of a first wavelength; a second light source configured to emit light of a second wavelength different from the first wavelength; an optical combining unit configured to optically combine light from the first light source and light from the second light source; a forming unit configured to form pattern light using light from the first light source; a projection optical system configured to project the optically combined light onto the object; an imaging unit configured to image the object on which the pattern light is projected by the projection optical system to capture a first image of the object; and a processing unit configured to obtain information of a shape of the object based on the first image, wherein the projection optical system is a common optical system configured to perform projection of light from the first light source and projection of light from the second light source, wherein the imaging unit images the object illuminated with light from the second light source via the projection optical system to capture a second image of the object, and wherein the processing unit corrects the first image using the second image and obtains information on the shape of the object based on the corrected first image, wherein the processing unit acquires information on a ratio of reflectances between a reflectance of light of the first wavelength and a reflectance of light of the second wavelength on the object, and wherein the processing unit converts pixel values of the second image into pixel values in the first wavelength using the information on the ratio of reflectances, corrects the first image using the converted pixel values of the second image, and obtains information of the shape of the object based on the corrected first image.",
    "2. The measurement apparatus according to claim 1, wherein the pattern light and light from the second light source pass through an aperture of a stop of the projection optical system before projecting onto the object.",
    "3. The measurement apparatus according to claim 1, wherein light at a bright portion of the pattern light and light from the second light source, which are projected from the projection optical system, individually include pieces of light equal in light intensity and equal in direction of a principal ray.",
    "4. The measurement apparatus according to claim 1, wherein an optical path of light from the first light source and an optical path of light from the second light source extend on a common axis by the optical combining unit.",
    "5. The measurement apparatus according to claim 1, wherein the light from the first light source and the light from the second light source optically combined by the optical combining unit fall on the forming unit, and wherein the forming unit includes a pattern having a transmittance varying depending on light of the first wavelength and light of the second wavelength.",
    "6. The measurement apparatus according to claim 5, wherein the pattern included in the forming unit includes a pattern made from a dielectric multi-layer film.",
    "7. The measurement apparatus according to claim 5, wherein the pattern included in the forming unit includes a micro-structure member a refractive index varying at a period equal to or less than a wavelength of incident light.",
    "8. The measurement apparatus according to claim 7, wherein the micro-structure member includes a photonic liquid crystal.",
    "9. The measurement apparatus according to claim 1, wherein the imaging unit performs imaging on the object with the pattern light reflected by the object and imaging on the object with the light emitted from the second light source and reflected by the object in synchronization with each other.",
    "10. The measurement apparatus according to claim 1, wherein a polarization state of light from the first light source and a polarization state of light from the second light source are equal.",
    "11. A system that grips and moves an object, the system comprising: the measurement apparatus according to claim 1 for measuring a shape of the object; a grip unit configured to grip the object; and a control unit configured to control the grip unit, wherein the control unit controls the grip unit using a result of measurement of the object by the measurement apparatus.",
    "12. A method for producing an article, the method comprising: measuring the shape of the object using the measurement apparatus according to claim 1; and producing the article by processing the object using a result of measurement of the object by the measurement apparatus.",
    "13. The measurement apparatus according to claim 1, wherein the object has a reflectance distribution on a surface of the object, and wherein the first image and the second image include information of the reflectance distribution."
  ],
  "description_excerpt": "Field\n\nAspects of the present invention generally relate to a measurement apparatus for measuring the shape of an object (an object to be measured), a system, and a method for producing an article.\n\nDescription of the Related Art\n\nAs one of techniques of measuring the shape of an object, there is known an optical measurement apparatus. The optical measurement apparatus can employ various methods, which include a method called a “pattern projection method”. The pattern projection method is to find the shape of an object by projecting a predetermined pattern onto the object, capturing an image of the object having the predetermined pattern projected thereon to obtain a captured image, detecting a pattern in the captured image, and calculating distance information (range information) in each pixel position according to the principle of triangulation.\n\nSuch a measurement method detects coordinates of each line of the projected pattern based on spatial distribution information about the amounts of received light (pixel values) in the captured image. However, the spatial distribution information about the amounts of received light is data including influences of, for example, a reflectance distribution caused by a pattern or design of the surface of an object to be measured or a reflectance distribution caused by a fine-structure shape of the surface of an object to be measured. These influences may cause detection errors in detecting the coordinates of a pattern or may make it impossible to perform such detection itself, and, as a result, information on the calculated shape of an object to be measured may become less accurate.",
  "cpc": [
    "G06K 9/00201",
    "B25J 9/1697",
    "G01B 11/2513",
    "G05B 2219/40564",
    "G06K 2209/401",
    "G06V 20/64",
    "G06V 2201/121",
    "Y10S 901/47"
  ],
  "ipc": [
    "B25J 9/16",
    "G01B 11/25",
    "G06K 9/00",
    "G06K 9/46"
  ],
  "assignees": [
    "Canon Inc"
  ],
  "inventors": [
    "Tsuyoshi Kitamura",
    "Akihiro HATADA"
  ],
  "filing_date": "2016-07-06",
  "publication_date": "2019-03-05",
  "grant_date": "2019-03-05",
  "priority_date": "2015-07-09",
  "application_number": "US-201615202966-A",
  "family_id": "57730014",
  "cited_by_count": 0,
  "citations": [
    "JPH03289505A",
    "JP2002213931A",
    "US20090059231A1",
    "US20100008588A1",
    "US20100046802A1",
    "US20110205356A1",
    "US20130238125A1",
    "US20170112360A1"
  ]
}