System employing preconditioned radiation for detecting defects in transparent objects

Claim 1

A method for inspecting a substantially transparent object having a complex shape wherein substantially transparent defects having relatively highly refractive surfaces on areas of interest of said object are detected and substantially transparent markings having surfaces which are less refractive on areas of interest of said object are not detected, said method comprising: (a) illuminating said transparent object with radiation having certain angular spectrum ranges for points of interest on said object; (b) selecting said angular spectrum ranges in order that radiation which is incident upon said transparent object and which passes through said defects is refracted outside of a limited angle of acceptance to a greater extent than is radiation which is incident upon adjacent non-defect areas; (c) conditioning said radiation in such a manner that a plurality of rays emanating from a single point on a source of said radiation are non-parallel prior to their incidence on said transparent object in order to provide radiation having average angles of incidence at various points of interest on said complex-shaped transparent object, said average angles of incidence being provided such that non-defect areas of said complex-shaped transparent object which are to be inspected are illuminated when viewed from a position of a means employed to detect the intensity of said radiation; (d) detecting the intensity of said radiation which falls within said limited angle of acceptance after having passed through said transparent object; and (e) analyzing the intensity of said radiation to determine whether defects are present.

Claim 2

A method for inspecting a substantially transparent object having a complex shape wherein substantially transparent defects having relatively highly refractive surfaces on areas of interest of said object are detected and substantially transparent markings having surfaces which are less refractive on areas of interest of said object are not detected, said method comprising: (a) illuminating said transparent object with radiation having certain angular spectrum ranges for points of interest on said object; (b) selecting said angular spectrum ranges in order that radiation which is incident upon said transparent object and which passes through said defects is refracted outside of a limited angle of acceptance to a greater extent than is radiation which is incident upon adjacent non-defect areas; (c) conditioning said radiation in such a manner that a plurality of rays emanating from a single point on a source of said radiation are non-parallel prior to their incidence on said transparent object in order to provide radiation having average angles of incidence at various points of interest on said complex-shaped transparent object, said average angles of incidence being provided such that non-defect areas of said complex-shaped transparent object which are to be inspected are illuminated when viewed from a position of a means employed to detect the intensity of said radiation; (d) detecting the intensity of said radiation which falls within said limited angle of acceptance after having passed through said transparent object; and (e) analyzing the intensity of said radiation to determine whether defects are present.

Claim 8

A method for inspecting a substantially transparent object having a complex shape wherein substantially transparent defects having highly refractive surfaces on areas of interest of said object are detected and substantially transparent markings having surfaces which are less refractive on areas of interest of said object are not detected, said method comprising: (a) illuminating said transparent object with radiation having certain angular spectrum ranges for points of interest on said object; (b) selecting said angular spectrum ranges in order that radiation which is incident upon said transparent object and which passes through said defects is refracted within a limited angle of acceptance to a greater extent than is radiation which is incident upon adjacent non-defect areas; (c) conditioning said radiation in such a manner that a plurality of rays emanating from a single point on a source of said radiation are non-parallel prior to their incidence on said transparent object in order that defects within areas of said transparent object which are to be inspected are illuminated when viewed from a position of a means employed to detect the intensity of said radiation; (d) detecting the intensity of said radiation which falls within said limited angle of acceptance after having passed through said transparent object; and (e) analyzing the intensity of said radiation to determine whether defects are present.

Claim 9

A method for inspecting a substantially transparent object having a complex shape wherein substantially transparent defects having highly refractive surfaces on areas of interest of said object are detected and substantially transparent markings having surfaces which are less refractive on areas of interest of said object are not detected, said method comprising: (a) illuminating said transparent object with radiation having certain angular spectrum ranges for points of interest on said object; (b) selecting said angular spectrum ranges in order that radiation which is incident upon said transparent object and which passes through said defects is refracted within a limited angle of acceptance to a greater extent than is radiation which is incident upon adjacent non-defect areas; (c) conditioning said radiation in such a manner that a plurality of rays emanating from a single point on a source of said radiation are non-parallel prior to their incidence on said transparent object in order that defects within areas of said transparent object which are to be inspected are illuminated when viewed from a position of a means employed to detect the intensity of said radiation; (d) detecting the intensity of said radiation which falls within said limited angle of acceptance after having passed through said transparent object; and (e) analyzing the intensity of said radiation to determine whether defects are present.

Claim 12

An apparatus for inspecting areas of interest on a substantially transparent object having a complex shape wherein said apparatus discriminates between substantially transparent defects having relatively highly refractive surfaces and transparent markings having surfaces which are less refractive, said apparatus comprising: (a) a radiation detection means which produces signals corresponding to the intensity of incident radiation falling within a limited angle of acceptance; (b) a source of radiation which illuminates said transparent object with radiation having certain angular spectrum ranges at points of interest on said object; (c) means for modifying the average angles of incidence of the radiation incident on said transparent object to be inspected wherein a plurality of rays originating from a single point on said source of radiation are non-parallel after passing through said means for modifying the average angles of incidence; and (d) processing means for analyzing the signals produced by said radiation detection means.

Claim 13

An apparatus for inspecting areas of interest on a substantially transparent object having a complex shape wherein said apparatus discriminates between substantially transparent defects having relatively highly refractive surfaces and transparent markings having surfaces which are less refractive, said apparatus comprising: (a) a radiation detection means which produces signals corresponding to the intensity of incident radiation falling within a limited angle of acceptance; (b) a source of radiation which illuminates said transparent object with radiation having certain angular spectrum ranges at points of interest on said object; (c) means for modifying the average angles of incidence of the radiation incident on said transparent object to be inspected wherein a plurality of rays originating from a single point on said source of radiation are non-parallel after passing through said means for modifying the average angles of incidence; and (d) processing means for analyzing the signals produced by said radiation detection means.

Claim 26

A method for determining the parameters for an inspection system comprising a radiation detection means comprising a video camera with a limited angle of acceptance, a radiation source comprising a diffuse light source followed by a stop which illuminates a transparent object with radiation having certain angular spectrum ranges at points of interest on the object, means for modifying the average angles of incidence of the radiation incident upon said object at such points, said means comprising a lens, and processing means; wherein said method comprises: (a) imaging said diffuse light source on a lens of said video camera so as to maximize the light incident at said camera and put the diffuse light source maximally out of focus; (b) selecting the angular spectrum range so that a greater portion of the light incident on defects in said transparent object is refracted outside of the limited angle of acceptance of the video camera than is the case with light incident upon non-defect areas; (c) selecting the average angles of incidence so that non-defect areas to be inspected appear illuminated from the point of view of said video camera; and (d) focusing said lens of said video camera on the areas of the transparent object to be inspected.

Claim 27

A method for determining the parameters for an inspection system comprising a radiation detection means comprising a video camera with a limited angle of acceptance, a radiation source comprising a diffuse light source followed by a stop which illuminates a transparent object with radiation having certain angular spectrum ranges at points of interest on the object, means for modifying the average angles of incidence of the radiation incident upon said object at such points, said means comprising a lens, and processing means; wherein said method comprises: (a) imaging said diffuse light source on a lens of said video camera so as to maximize the light incident at said camera and put the diffuse light source maximally out of focus; (b) selecting the angular spectrum range so that a greater portion of the light incident on defects in said transparent object is refracted outside of the limited angle of acceptance of the video camera than is the case with light incident upon non-defect areas; (c) selecting the average angles of incidence so that non-defect areas to be inspected appear illuminated from the point of view of said video camera; and (d) focusing said lens of said video camera on the areas of the transparent object to be inspected.