Optical inspection system utilizing wedge shaped spatial filter

Claim 2

A spatial filter for selectively filtering scattered radiation created as a result of a source radiation beam striking a planar surface having a plurality of grooves therein which intersect at various angles less than or equal to a predetermined maximum angle, said spatial filter comprising: a first nontransmissive area having a predetermined width for blocking direct reflection of said source radiation beam from said planar surface; and at least one radially disposed substantially wedge-shaped transmissive area extending outward from said first nontransmissive area, said at least one radially disposed substantially wedge-shaped transmissive area having a width substantially equal to said predetermined width at a point proximate to said first nontransmissive area and increasing in width at a selected angle from a bisector of said radially disposed substantially wedge-shaped transmissive area, said selected angle being substantially equal to said predetermined maximum angle.

Claim 3

The spatial filter of claim 1, wherein said spatial filter includes two diametrically opposing radially disposed substantially wedge-shaped transmissive areas.

Claim 4

The spatial filter of claim 1, wherein said at least one radially disposed substantially wedge-shaped transmissive area is aligned with said scattered radiation.

Claim 5

A spatial filter for selectively filtering scattered radiation created as a result of a source radiation beam striking a planar surface having a plurality of grooves therein which intersect at various angles less than or equal to a predetermined maximum angle, said spatial filter comprising: a first nontransmissive area having a predetermined width for blocking direct reflection of said source radiation beam from said planar surface; and at least one radially disposed substantially wedge-shaped nontransmissive area extending outward from said first nontransmissive area, said at least one radially disposed substantially wedge-shaped nontransmissive area having a width substantially equal to said predetermined width at a point proximate to said first nontransmissive area and increasing in width at a selected angle from a bisector of said radially disposed substantially wedge-shaped nontransmissive area, said selected angle being substantially equal to said predetermined maximum angle.

Claim 6

A spatial filter for selectively filtering scattered radiation created as a result of a source radiation beam striking a planar surface having a plurality of grooves therein which intersect at various angles less than or equal to a predetermined maximum angle, said spatial filter comprising: a first nontransmissive area having a predetermined width for blocking direct reflection of said source radiation beam from said planar surface; and at least one radially disposed substantially wedge-shaped nontransmissive area extending outward from said first nontransmissive area, said at least one radially disposed substantially wedge-shaped nontransmissive area having a width substantially equal to said predetermined width at a point proximate to said first nontransmissive area and increasing in width at a selected angle from a bisector of said radially disposed substantially wedge-shaped nontransmissive area, said selected angle being substantially equal to said predetermined maximum angle.

Claim 7

The spatial filter of claim 4, wherein said spatial filter includes two diametrically opposing radially disposed substantially wedge-shaped nontransmissive areas.

Claim 10

The system of claim 6 further comprising: means responsive to said reference beam and producing a second signal thereof; and means for producing a final signal from said first signal and said second signal.

Claim 11

The system of claim 7, wherein said means for producing a final signal includes passing said first signal and said second signal through a division module.

Claim 12

The system of claim 6, wherein said means for spatially filtering radiation scattered from said planar surface includes a spatial filter configured to transmit light scattered by said plurality of grooves to said means responsive to said radiation scattered from said planar surface.

Claim 13

The system of claim 6, wherein said planar surface includes a defect and said means for spatially filtering radiation scattered from said planar surface includes a spatial filter configured to transmit radiation scattered by said defect to said means responsive to radiation scattered from said planar surface.

Claim 14

The system of claim 9, wherein said reference beam travels along an axis, said means responsive to radiation scattered from said planar surface is aligned off said axis allowing said reference beam to pass said means responsive to said radiation scattered from said planar surface; and said spatial filter comprises a nontransmissive area and at least one wedge-shaped transmissive area having a first end located proximately to said axis and a second end located distally to said axis, said at least one wedge-shaped transmissive area being radially disposed relative to said axis and having a predetermined width at said first end and increasing in width towards said outer edge at an angle from a bisector of said at least one wedge-shaped transmissive area, said angle having a vertex on said bisector and being equal to said predetermined maximum angle.

Claim 15

The system of claim 9, wherein said spatial filter is for selectively filtering scattered radiation, said spatial filter comprising: a first nontransmissive area having a predetermined width; at least one radially disposed substantially wedge-shaped transmissive area extending outward from said first nontransmissive area, said at least one radially disposed transmissive area having a width equal to said predetermined width at a point proximate to said first nontransmissive area and increasing in width at a selected angle from a bisector of said radially disposed transmissive area, said selected angle having a vertex on said bisector and being substantially equal to said predetermined maximum angle; and a second nontransmissive area surrounding said first transmissive area and said at least one radially disposed substantially wedge-shaped transmissive area.

Claim 16

The system of claim 10, wherein said spatial filter is a spatial filter for selectively filtering scattered radiation created as a result of a source radiation beam striking a planar surface having a plurality of grooves therein, which intersect at various angles and less than or equal to a predetermined maximum angle, said spatial filter comprising: a first nontransmissive area having a predetermined width for blocking direct reflection of said source radiation beam from said planar surface; at least one radially disposed substantially wedge-shaped nontransmissive area extending outward from said first nontransmissive area, said at least one radially disposed transmissive area having a width equal to said predetermined width at a point proximate to said first nontransmissive area and increasing in width at a selected angle from a bisector of said radially disposed transmissive area, said selected angle being substantially equal to said predetermined maximum angle; and a transmissive area surrounding said first nontransmissive area and said at least one radially disposed substantially wedge-shaped nontransmissive area.

Claim 17

The system of claim 6, wherein said radiation source is a coherent light source.

Claim 18

The system of claim 14, wherein said radiation source is a HeNe laser.

Claim 19

A spatial filter for transmitting scattered radiation created by a source radiation beam perpendicularly striking a planar surface having a plurality of grooves therein intersecting at various angles less than or equal to a predetermined maximum angle, to a detector and for blocking transmission of a reflected radiation beam traveling along an axis to said detector, said reflected beam originating from said source radiation beam reflected from said surface, said spatial filter comprising: a nontransmissive area including a circular section having a circumferential edge and two points, a first point and a second point, diametrically opposed on said circumferential edge along a line vertically bisecting said circular section, said first point located above said second point, said circular section aligned coincidental with said axis of said reflected radiation beam, and said central section shaped to block transmission of said reflected radiation beam to said detector; a first positioning line extending horizontally from said first point and a second positioning line extending horizontally from said second point; a transmissive area having a wedge-shaped section extending away from said circular section, said wedge-shaped section having a first end proximally located to said circular section and terminating in a second end, said second larger than said first end, said section further defined by a first line extending from said first point away from said circular section to said second end at an angle from said first positioning line, wherein said angle is equal to said predetermined maximum angle and a second line extending from said second point away from said circular section to said second end at said angle from said second positioning line; and said nontransmissive area having a third section surrounding said circular section and said second section and configured to block radiation transmission of radiation not transmitted by said second to said detector.

Claim 20

A spatial filter for transmitting scattered radiation created by a source radiation beam perpendicularly striking a planar surface having a plurality of grooves therein intersecting at various angles less than or equal to a predetermined maximum angle, to a detector and for blocking transmission of a reflected radiation beam traveling along an axis to said detector, said reflected beam originating from said source radiation beam reflected from said surface, said spatial filter comprising: a nontransmissive area including a circular section having a circumferential edge and two points, a first point and a second point, diametrically opposed on said circumferential edge along a line vertically bisecting said circular section, said first point located above said second point, said circular section aligned coincidental with said axis of said reflected radiation beam, and said central section shaped to block transmission of said reflected radiation beam to said detector; a first positioning line extending horizontally from said first point and a second positioning line extending horizontally from said second point; a transmissive area having a wedge-shaped section extending away from said circular section, said wedge-shaped section having a first end proximally located to said circular section and terminating in a second end, said second larger than said first end, said section further defined by a first line extending from said first point away from said circular section to said second end at an angle from said first positioning line, wherein said angle is equal to said predetermined maximum angle and a second line extending from said second point away from said circular section to said second end at said angle from said second positioning line; and said nontransmissive area having a third section surrounding said circular section and said second section and configured to block radiation transmission of radiation not transmitted by said second to said detector.