Illumination for inspecting surfaces of articles

• US 6,832,843 B2
• Filed: 07/23/2002
• Issued: 12/21/2004
• Est. Priority Date: 08/05/1999
• Status: Expired due to Fees

• Current Assignee: Orbotech Limited (KLA Corporation)
• Original Assignee: Orbotech Limited (KLA Corporation)
• Inventors: Ben Shlomo, Moshe, Adler, Avraham
• Primary Examiner(s): CARIASO, ALAN B
• Application Number:
  US10/200,147
• Publication Number:
  US 20020181233A1
• Time in Patent Office: 882 Days
• Field of Search: 355/70, 358/473-475, 358/480-482, 358/484, 362/241, 362/245, 362/247, 362/259, 362/268, 362/297, 362/346, 362/554
• US Class Current: 362/247
• CPC Class Codes: G01N 21/95684 Patterns showing highly reflecting parts, e.g. metallic elements

Abstract

An illumination system including at least one reflector subtending an angle with respect to a location on a surface of an article, and first and second light sources, the first and second light sources each providing a light output, the light outputs from both of the first and second light sources being directed to impinge on the location on the surface of an article within the angle, at least one of the light outputs being reflected by the reflector.

Claims

1. An illumination system comprising:

at least one reflector subtending an angle with respect to a location on a surface of an article and having formed therein a light transmissive region;

a light source consisting of first and second light illuminators, said light transmissive region being configured to permit light from a first one of said first and second illuminators to pass therethrough; and

an optical element including at least one reflecting surface disposed intermediate said first one of said first and second illuminators and said light transmissive region for directing the light output of said first one of said first and second illuminators through said light transmissive region;

said first and second illuminators each providing a light output, the light outputs from both of said first and second illuminators being directed to impinge on said location on said surface of an article from within said angle, at least one of said light outputs being reflected by said reflector, wherein a light output from said first illuminator illuminates said location from within a solid angle of illumination that is narrower than said angle.

2. An illumination system according to claim 1, wherein said light transmissive region is an aperture formed in said reflector.

3. An illumination system according to claim 1, further comprising an optical assembly disposed along an optical path extending between said optical element and said location on the surface of an article for directing light reflected from said location on the surface of an article to a light sensor.

4. An illumination system according to claim 3, wherein said optical assembly is generally transmissive to said the light output of said first one of said first and second illuminators directed through said light transmissive region onto said location on the surface of an article and generally reflective of light reflected from said location on the surface of an article.

5. An illumination system according to claim 1, further comprising a reflective surface disposed intermediate a second one of said first and second illuminators and said reflector for directing the light output of said second one of said first and second light sources onto said reflector.

6. An illumination system according to claim 1, wherein said at least one reflector is an elliptical reflector and a second one of said first and second illuminators and said location on the surface of an article are each located at a locus of said elliptical reflector.

7. An illumination system according to claim 6, wherein said at least one reflector comprises two spaced apart reflectors which together define a section of an ellipse.

8. An illumination system according to claim 1, wherein said first and second illuminators comprise independently controllable illuminators.

9. An illumination system according to claim 1, wherein said first and second illuminators comprise a plurality of light emitters.

10. An illumination system according to claim 9, wherein said plurality of light emitters comprises a plurality of optical fibers receiving light from a projection lamp.

11. An illumination system comprising:

a cylindrical reflector extending along a first longitudinal axis and having an axial aperture formed therein which extends along said longitudinal axis;

a first elongate light source extending along a second longitudinal axis, generally parallel to said first longitudinal axis and being arranged to illuminate portions of said cylindrical reflector disposed along both sides of said axial aperture, such that light from said first elongate light source is directed by said portions onto a plane generally along a third longitudinal axis, generally parallel to said first and second longitudinal axes;

a second elongate light source extending along a fourth longitudinal axis, generally parallel to said first, second and third longitudinal axes, said second elongate light source being arranged with respect to said axial aperture of said cylindrical reflector such that light from said second elongate light source is directed through said axial aperture onto said plane generally along said third longitudinal axis; and

an optical element disposed along a light path between said second elongate light source and said plane and being operative to pass light from said second elongate light source to said plane and to reflect light from said plane to an optical sensor.

12. An illumination system comprising:

a cylindrical reflector extending along a first longitudinal axis and having an axial aperture formed therein which extends along said longitudinal axis;

a first elongate light source extending along a second longitudinal axis, generally parallel to said first longitudinal axis and being arranged to illuminate said cylindrical reflector, such that light from said first elongate light source is directed onto a plane generally along a third longitudinal axis, generally parallel to said first and second longitudinal axes;

a second elongate light source extending along a fourth longitudinal axis, generally parallel to said first, second and third longitudinal axes, said second elongate light source being arranged with respect to said axial aperture of said cylindrical reflector such that light from said second elongate light source is directed through said axial aperture onto said plane generally along said third longitudinal axis; and

an optical element disposed along a light path between said second elongate light source and said plane and being operative to pass light from said second elongate light source to said plane and to reflect light from said plane to an optical sensor;

wherein said first elongate light source comprises an elongate light generating element and an elongate reflector extending along a fifth longitudinal axis, generally parallel to said first, second, third and fourth longitudinal axes and being operative to reflect light from said elongate light generating element onto said cylindrical reflector.