Device and method for measuring distortion defects in a manufactured float glass strip

{
  "publication_number": "US10060858B2",
  "country": "US",
  "kind": "B2",
  "title": "Device and method for measuring distortion defects in a manufactured float glass strip",
  "abstract": "The invention relates to a method and a device for the rapid and reliable measuring of distortion defects in a manufactured float glass strip, having the following features: a) a linear inset LED light source (5) sweeping the breadth of the glass strip (4) to be examined, said light source having LEDs that are tightly packed one next to the other below a glass strip (4) to be examined, b) a linear cylindrical lens 8) which is arranged in parallel to the entire length of the inset LED light source (5) and the distance of which to the inset LED light source (5) is continuously variable, c) a light source (2) arranged above the glass strip (4), d) an array of at least 4 CCD cameras arranged above the glass strip (4), and a two-stage parallel signal evaluation unit.",
  "claims": [
    "1. A device for rapidly and reliably measuring distortion defects in a manufactured float glass strip, comprising: a linear inset LED light source (5) positioned below the manufactured float glass strip (4) to be examined, said linear inset LED light source having LEDs arranged alongside one another, wherein the linear inset LED light source comprises at least two types of LEDs having different wavelengths in an arbitrary sequence, and the linear inset LED light source (5) is inclined at an acute angle, measured from a perpendicular plane with respect to the manufactured float glass strip, a cylindrical lens element (9) arranged linearly and parallel to the entire length of the linear inset LED light source (5), the distance between said cylindrical lens element and the linear inset LED light source (5) being adjustable in a continuously variable manner, wherein said cylindrical lens element is arranged below the manufactured float glass strip (4) in the plane of a beam path between the linear inset LED luminaire (5) and an arrangement of at least four CCD cameras (1) arranged in a series above the manufactured float glass strip (4), a light source (2) arranged above the manufactured float glass strip (4), wherein said light source (2) is inclined at an acute angle, measured from a perpendicular plane with respect to the manufactured float glass strip, and positioned on the same side of the perpendicular plane as the linear inset LED light source (5), wherein lenses of said at least four CCD cameras are optionally equipped with a slit diaphragm (16), a blade diaphragm (18) and/or a dichroic and/or a trichroic filter, a controller adapted to carry out a two-stage parallel signal evaluation, wherein bitmaps from all channels are processed in parallel and further data are concomitantly included, wherein the linear inset LED light source (5) and the CCD cameras (1) lie opposite one another relative to the glass strip (4) to be examined, wherein the linear inset LED light source (5) and the CCD cameras (1) are inclined with respect to one another in their optical connecting axis, and wherein a lower light source protection element (6) is mounted areally in front of the linear inset LED light source (5), and an upper light source protection element (3) is mounted areally in front the CCD cameras (1).",
    "2. The device as claimed in claim 1, wherein the LEDs have a wavelength corresponding to the color green, blue, or both.",
    "3. A method for measuring distortion defects in a manufactured float glass strip, comprising: irradiating the manufactured float glass strip (4) to be examined with a linear inset LED light source (5) arranged below the manufactured float glass strip (4) to be examined, said linear inset LED light source having LEDs arranged alongside one another, wherein the linear inset LED light source comprises at least two types of LEDs having different wavelengths in an arbitrary sequence, and the linear inset LED light source (5) is inclined at an acute angle, measured from a perpendicular plane with respect to the manufactured float glass strip to be examined, adjusting in a continuously variable manner a distance between the linear inset LED light source (5) and a cylindrical lens element (8) arranged linearly and parallel to the entire length of the linear inset LED light source (5), wherein said cylindrical lens element is arranged below the manufactured float glass strip (4) in the plane of a beam path between the linear inset LED light source (5) and an arrangement of at least four CCD cameras (1) arranged in a series above the manufactured float glass strip (4), focusing the beam path to carry out a point imaging of an LED in a measurement plane of a CCD camera (1) arranged above the manufactured float glass strip (4), progressing the manufactured float glass strip (4) in a production line, and conducting a two-stage parallel signal evaluation of the manufactured float glass strip (4), wherein bitmaps from all channels are processed in parallel and further data from the production line are concomitantly included, wherein the linear inset LED light source (5) and the CCD cameras (1) lie opposite one another relative to the glass strip (4) to be examined, wherein the linear inset LED light source (5) and the CCD cameras (1) are inclined with respect to one another in their optical connecting axis, and wherein a lower light source protection element (6) is mounted areally in front of the linear inset LED light source (5), and an upper light source protection element (3) is mounted areally in front the CCD cameras (1).",
    "4. The method as claimed in claim 3, wherein LEDs having a wavelength corresponding to the color green and LEDs having a wavelength corresponding to the color blue are used.",
    "5. A machine-readable carrier comprising a non-transitory program code of a computer program for performing the method as claimed in claim 3 when the program is executed in a computer."
  ],
  "description_excerpt": "The invention relates to a device and a method for rapidly and reliably measuring distortion defects in a manufactured float glass strip. A whole-area measurement of the thickness variation and of the refractive power variation is possible in this case.\n\nWith regard to the prior art, a method and a device for determining optical defects are known from the patent specification EP 1 288 651 B1.\n\nIn this case, the preamble of patent claim 1 proceeds from a device for determining optical defects, in particular in the refractive power, in large-area sheets of a transparent material such as glass by means of an evaluation of the observed image, comprising the following features:\n\nA light source for projecting a defined pattern of regular sequences, wherein the sequences comprise at least two different light intensities; means for arranging the sheet in the beam path of the projection, and, as a further feature, a camera, wherein sequences of the pattern are directed onto pixels of the camera. Said patent specification is based on the objective, inter alia, of specifying a device according to the preamble of patent claim 1 which can be used to determine optical defects in at least one dimension of a sheet.\n\nFor this purpose, according to the indications in the characterizing part of patent claim 1, what was afforded protection was that the light source is a luminous wall embodied as a luminous matrix and comprising a multiplicity of LEDs which can be driven selectively, preferably in lines and/or columns.",
  "cpc": [
    "G01N 21/896",
    "G01N 21/8903",
    "G01N 21/958",
    "G01N 2201/062"
  ],
  "ipc": [
    "G01N 21/89",
    "G01N 21/896"
  ],
  "assignees": [
    "Grenzebach Maschinenbau GmbH"
  ],
  "inventors": [
    "Leonhard Schwab"
  ],
  "filing_date": "2015-05-29",
  "publication_date": "2018-08-28",
  "grant_date": "2018-08-28",
  "priority_date": "2014-06-10",
  "application_number": "US-201515313867-A",
  "family_id": "53782998",
  "cited_by_count": 4,
  "citations": [
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    "US20110141270A1",
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  ]
}