Compact laser scanning system

Claim 2

A laser scanning system comprising a laser source (21) for producing a laser light beam; scanning means (27) positioned for receiving and redirecting the laser beam so as to scan in a predetermined plane; and a target (W) positioned for receiving the scanned beam; characterized in that a folded optical cell (30) is interposed between the scanning means (27) and the target (W), said folded optical cell including a pair of reflective surfaces so oriented with respect to one another as to cause the scanned beam to be reflected from each of the reflective surfaces a plurality of times in its course of travel from said scanning means (27) to said target (W) to thereby significantly increase the overall effective length of travel of the laser beam between the scanning means and the target.

Claim 3

A laser scanning system according to Claim 1 wherein said folded optical cell includes first and second mirrors (31,32) mounted in opposed spaced apart relation to one another and defining said pair of reflective surfaces.

Claim 4

A laser scanning system according to Claim 2 wherein one of said mirrors (31) has a planar reflective surface and the other mirror (32) has a concave curved reflective surface effective to cause the scanning beam to move in a collimated, parallel scan pattern..

Claim 5

A laser scanning system according to Claim 3 wherein said concave curved reflective surface is parabolic.

Claim 6

A laser scanning system according to Claim 3 wherein said concave curved reflective surface is spherical.

Claim 7

A laser scanning system according to Claim 1 wherein said target (W) lies in a predetermined target plane and has predetermined length and width dimensions, wherein said scanning system additionally includes means (40) for moving the target (W) while in said target plane along a predetermined path of travel extending transversely of the scan path (L) of the laser beam so that the entire length and width of the target is scanned by the laser beam during said movement of the target.

Claim 8

A laser surface inspection system comprising a laser source (21) for producing a laser light beam; scanning means (27) positioned for receiving and redirecting the laser beam so as to scan in a predetermined plane; and a target (W) having an inspection surface positioned for receiving the scanned beam; characterized in that a folded optical cell (30) is interposed between the scanning means and the target (W); said folded optical cell including a pair of reflective surfaces (31,32) so oriented with respect to one another as to cause the scanned beam to be reflected from each of the reflective surfaces a plurality of times in its course of travel from said scanning means to said target to thereby significantly increase the overall effective length of travel of the laser beam between the scanning means and the target; and detector means is positioned for receiving light reflected from said target and for determining therefrom the surface characteristics of the target.

Claim 9

A laser surface inspection system comprising a laser source (21) for producing a laser light beam; scanning means (27) positioned for receiving and redirecting the laser beam so as to scan in a predetermined plane; and a target (W) having an inspection surface positioned for receiving the scanned beam; characterized in that a folded optical cell (30) is interposed between the scanning means and the target (W); said folded optical cell including a pair of reflective surfaces (31,32) so oriented with respect to one another as to cause the scanned beam to be reflected from each of the reflective surfaces a plurality of times in its course of travel from said scanning means to said target to thereby significantly increase the overall effective length of travel of the laser beam between the scanning means and the target; and detector means is positioned for receiving light reflected from said target and for determining therefrom the surface characteristics of the target.

Claim 10

A laser surface inspection system according to Claim 7 wherein said detector means includes a dark field light detector (57) and means for directing scattered light which is reflected from the surface of said target into said dark field light detector.

Claim 11

A laser surface inspection system according to Claim 7 wherein said detector means includes a bright field light detector (39) and means for directing light which is specularly reflected from the target into said bright field light detector, said bright field light detector being so positioned that the specularly reflected beam is directed into said folded optical cell (30) and is reflected from each of the reflective surfaces thereof a plurality of times in its course of travel from the target to said bright field light detector.

Claim 12

A laser surface inspection system according to Claim 9 wherein said means for directing specularly reflected light into said bright field light detector (39) includes means for directing only the central image portion of the specularly reflected beam into said bright field light detector and wherein said detector means additionally includes a near field light detector (70) and means for directing the remaining surrounding portion of the specularly reflected beam surrounding said central image portion into said near field light detector.

Claim 13

A laser surface inspection system comprising a laser source (21) for producing a laser light beam; scanning means (27) positioned for receiving and redirecting the laser beam so as to scan in a predetermined plane; and a target (W) having an inspection surface positioned for receiving the scanned beam; characterized in that a folded optical cell (30) is interposed between the scanning means and the target, said folded optical cell including a pair of reflective surfaces (31,32) so oriented with respect to one another as to cause the scanned beam to be reflected from each of the reflective surfaces a plurality of times in its course of travel from said scanning means to said target to thereby significantly increase the overall effective length of travel of the laser beam between the scanning means and the target; and detector means is positioned for receiving light reflected from said target and for determining therefrom the surface characteristics of the target, said detector means including a light detector (57), a light tube (52) optically connected to said light detector, and an ellipsoidal mirror (50) located adjacent to the inspection surface and being so positioned that the intersection of the laser scan line (L) with the inspection surface and the longitudinal axis of said light tube (52) lie at the respective foci of the ellipsoidal mirror (50) whereby substantially all of the scattered light which is reflected from the inspection surface along said scan line is directed into the light tube.

Claim 14

A laser surface inspection system comprising a laser source (21) for producing a laser light beam; scanning means (27) positioned for receiving and redirecting the laser beam so as to scan in a predetermined plane; and a target (W) having an inspection surface positioned for receiving the scanned beam; characterized in that a folded optical cell (30) is interposed between the scanning means and the target, said folded optical cell including a pair of reflective surfaces (31,32) so oriented with respect to one another as to cause the scanned beam to be reflected from each of the reflective surfaces a plurality of times in its course of travel from said scanning means to said target to thereby significantly increase the overall effective length of travel of the laser beam between the scanning means and the target; and detector means is positioned for receiving light reflected from said target and for determining therefrom the surface characteristics of the target, said detector means including a light detector (57), a light tube (52) optically connected to said light detector, and an ellipsoidal mirror (50) located adjacent to the inspection surface and being so positioned that the intersection of the laser scan line (L) with the inspection surface and the longitudinal axis of said light tube (52) lie at the respective foci of the ellipsoidal mirror (50) whereby substantially all of the scattered light which is reflected from the inspection surface along said scan line is directed into the light tube.

Claim 15

A laser surface inspection system comprising a laser source (21) for producing a laser light beam; scanning means (27) positioned for receiving and redirecting the laser beam so as to scan in a predetermined plane and along a predetermined scan line (L); and means (40) for advancing a test article (W) along a predetermined path of travel transversely of said scan line and with the inspection surface of the test article positioned in a predetermined target plane for receiving the scanned beam thereacross; and characterized in that a folded optical cell (30) is interposed between the scanning means and the test article, said folded optical cell including a pair of mirrors (31,32) mounted in opposed spaced apart relation and including respective reflective surfaces so oriented with respect to one another as to cause the scanned beam to be reflected from each of the reflective surfaces a plurality of times in its course of travel from said scanning means to the inspection surface to thereby significantly increase the overall effective length of travel of the laser beam between the scanning means and the inspection surface; and detector means is positioned for receiving light reflected from the inspection surface, said detector means including a dark field light detector (57) and means for directing scattered light which is reflected from said inspection surface into said dark field light detector, and said detector means also including a bright field light detector (39) and means for directing light specularly reflected from said surface into said bright field light detector.

Claim 16

A laser surface inspection system comprising a laser source (21) for producing a laser light beam; scanning means (27) positioned for receiving and redirecting the laser beam so as to scan in a predetermined plane and along a predetermined scan line (L); and means (40) for advancing a test article (W) along a predetermined path of travel transversely of said scan line and with the inspection surface of the test article positioned in a predetermined target plane for receiving the scanned beam thereacross; and characterized in that a folded optical cell (30) is interposed between the scanning means and the test article, said folded optical cell including a pair of mirrors (31,32) mounted in opposed spaced apart relation and including respective reflective surfaces so oriented with respect to one another as to cause the scanned beam to be reflected from each of the reflective surfaces a plurality of times in its course of travel from said scanning means to the inspection surface to thereby significantly increase the overall effective length of travel of the laser beam between the scanning means and the inspection surface; and detector means is positioned for receiving light reflected from the inspection surface, said detector means including a dark field light detector (57) and means for directing scattered light which is reflected from said inspection surface into said dark field light detector, and said detector means also including a bright field light detector (39) and means for directing light specularly reflected from said surface into said bright field light detector.

Claim 17

A laser surface inspection system according to Claim 12 wherein said bright field light detector (39) is so positioned that the specularly reflected beam from the inspection surface is directed into said folded optical cell (30) and is reflected from the respective reflective surfaces thereof a plurality of times in its course of travel from the surface to said bright field light detector.

Claim 18

A laser surface inspection system according to Claim 13 wherein the path of travel of said specularly reflected beam between the inspection surface and said optical cell is in a plane different from said predetermined plane of the incident scanning beam, and including an opaque shield (80) located between the planes of the incident beam and the reflected beam for isolating the reflected beam from the incident beam.

Claim 19

A laser surface inspection system according to Claim 12 wherein said means for directing scattered light into said dark field light detector (57) comprises a light tube (52) optically connected to said dark field light detector (57) for receiving light and conducting it into said detector, and an ellipsoidal mirror (50) located adjacent to the inspection surface and being so positioned that the intersection of the laser scan line with the inspection surface and the longitudinal axis of said light tube lie at the respective foci of the ellipsoidal mirror whereby substantially all of the scattered light which is reflected from the inspection surface along said scan line is directed into the light tube.