Single axis beam scanner

Claim 1

A method of scanning a high power laser beam onto a metal workpiece surface to distribute power substantially uniformly over a selected area of the workpiece surface for metallurgically heat treating the selected area of the surface, said method comprising: directing an input high power laser beam at a first mirror at an average angle beta to its surface, the first mirror rotating about an axis passing centrally through the mirror's surface, the mirror being tilted such that a perpendicular to the surface is at an angle alpha from the axis of rotation; positioning a second mirror in the path of the reflected beam from the first mirror, such that the beam from the first mirror strikes the second mirror at the same average angle beta to its surface, while rotating the second mirror in the opposite direction and at the same angular speed as the first about an axis passing centrally through the second mirror's surface, the second mirror being tilted such that a perpendicular to its surface is at approximately the same angle alpha from its axis of rotation; selecting the mirror positions and adjusting the phase of the two rotating mirrors such that the resulting beam scan reciprocates substantially in a straight line on the metal workpiece surface, and effecting a metallurgical change in the selected area of the workpiece surface scanned by the beam through the heating produced by the high power scanned beam.

Claim 2

A method of scanning a high power laser beam onto a metal workpiece surface to distribute power substantially uniformly over a selected area of the workpiece surface for metallurgically heat treating the selected area of the surface, said method comprising: directing an input high power laser beam at a first mirror at an average angle beta to its surface, the first mirror rotating about an axis passing centrally through the mirror's surface, the mirror being tilted such that a perpendicular to the surface is at an angle alpha from the axis of rotation; positioning a second mirror in the path of the reflected beam from the first mirror, such that the beam from the first mirror strikes the second mirror at the same average angle beta to its surface, while rotating the second mirror in the opposite direction and at the same angular speed as the first about an axis passing centrally through the second mirror's surface, the second mirror being tilted such that a perpendicular to its surface is at approximately the same angle alpha from its axis of rotation; selecting the mirror positions and adjusting the phase of the two rotating mirrors such that the resulting beam scan reciprocates substantially in a straight line on the metal workpiece surface, and effecting a metallurgical change in the selected area of the workpiece surface scanned by the beam through the heating produced by the high power scanned beam.

Claim 8

A method of scanning a high power laser beam onto a metal workpiece surface to distribute power substantially uniformly over a selected area of the workpiece surface for metallurgically heat treating the selected area of the surface, said method comprising: reflecting an input high power laser beam off a first mirror and from there off a second mirror, at substantially the same average angle of incidence at both mirrors; rotating both mirrors, simultaneously at the same speed in opposite directions, each about an axis that is tilted a small angle from a perpendicular to the mirror's reflecting surface, thereby forming on a work surface generally perpendicular to the final reflected beam a pattern represented by the resultant of two theoretical ellipses, each of which would be formed by one of the mirrors acting alone with the other stationary, the two ellipses being substantially similar and when superimposed, forming a pattern generally symmetrical about a bisector between the major axes of the two ellipses; adjusting the phase relationship of the two rotating mirrors such that the resulting beam scan reciprocates in substantially a straight line along the bisector of the major axes of the ellipses on the metal workpiece surface, and effecting a metallurgical change in the selected area of the workpiece surface scanned by the beam through the heating produced by the high power scanned beam.

Claim 9

A method of scanning a high power laser beam onto a metal workpiece surface to distribute power substantially uniformly over a selected area of the workpiece surface for metallurgically heat treating the selected area of the surface, said method comprising: reflecting an input high power laser beam off a first mirror and from there off a second mirror, at substantially the same average angle of incidence at both mirrors; rotating both mirrors, simultaneously at the same speed in opposite directions, each about an axis that is tilted a small angle from a perpendicular to the mirror's reflecting surface, thereby forming on a work surface generally perpendicular to the final reflected beam a pattern represented by the resultant of two theoretical ellipses, each of which would be formed by one of the mirrors acting alone with the other stationary, the two ellipses being substantially similar and when superimposed, forming a pattern generally symmetrical about a bisector between the major axes of the two ellipses; adjusting the phase relationship of the two rotating mirrors such that the resulting beam scan reciprocates in substantially a straight line along the bisector of the major axes of the ellipses on the metal workpiece surface, and effecting a metallurgical change in the selected area of the workpiece surface scanned by the beam through the heating produced by the high power scanned beam.

Claim 10

A method of scanning a laser beam onto a workpiece, comprising: reflecting an input laser beam off a first mirror and from there off a second mirror, at substantially the same average angle of incidence at both mirrors; rotating both mirrors, simultaneously at the same speed in opposite directions, each about an axis that is tilted a small angle from a perpendicular to the mirror's reflecting surface, thereby forming on a work surface generally perpendicular to the final reflected beam a pattern represented by the resultant of two theoretical ellipses, each of which would be formed by one of the mirrors acting alone with the other stationary, the two ellipses being substantially similar and when superimposed, forming a pattern generally symmetrical about a bisector between the major axes of the two ellipses; and adjusting the phase relationship of the two rotating mirrors such that the resulting beam scan reciprocates in substantially a straight line along the bisector of the major axes of the ellipses, and wherein the average angle of incidence is about 45° and wherein the input beam and the centers of the two mirrors are in a plane parallel to the work surface, whereby the major axes of the two ellipses are at 90° to one another.

Claim 11

A method of scanning a laser beam onto a workpiece, comprising: reflecting an input laser beam off a first mirror and from there off a second mirror, at substantially the same average angle of incidence at both mirrors; rotating both mirrors, simultaneously at the same speed in opposite directions, each about an axis that is tilted a small angle from a perpendicular to the mirror's reflecting surface, thereby forming on a work surface generally perpendicular to the final reflected beam a pattern represented by the resultant of two theoretical ellipses, each of which would be formed by one of the mirrors acting alone with the other stationary, the two ellipses being substantially similar and when superimposed, forming a pattern generally symmetrical about a bisector between the major axes of the two ellipses; and adjusting the phase relationship of the two rotating mirrors such that the resulting beam scan reciprocates in substantially a straight line along the bisector of the major axes of the ellipses, and wherein the average angle of incidence is about 45° and wherein the input beam and the centers of the two mirrors are in a plane parallel to the work surface, whereby the major axes of the two ellipses are at 90° to one another.

Claim 12

An apparatus for scanning a high power laser beam onto a workpiece surface to distribute power substantially uniformly over a selected area of the workpiece surface for metallurgically heat treating the selected area of the surface, said apparatus comprising: beam generating means for generating an input high power laser beam; a laser scanner frame; a first mirror mounted on a first shaft journalled for rotation on the frame, the mirror having a reflecting surface which is tilted at a small angle from perpendicularity to the shaft; a second mirror mounted on a second shaft journalled for rotation on the frame, the second mirror having a reflecting surface which is tilted at a small angle from perpendicularity to the second shaft, said small angles being approximately equal; the first mirror being positioned in the path of the input laser beam and the second mirror being positioned in the path of the beam reflected from the first mirror, the two mirrors being so positioned that the laser beam makes approximately the same angle of incidence on each mirror; workpiece retaining means for holding a workpiece with a work surface approximately perpendicular to the reflected beam from the second mirror; rotating means attached to the frame for rotating the two mirrors at the same rotational speed and in opposite directions; and phase adjusting means attached to the frame for adjusting the relative phasing of the two mirrors, to produce a substantially straight line reciprocating resultant scan on the work surface.

Claim 13

An apparatus for scanning a high power laser beam onto a workpiece surface to distribute power substantially uniformly over a selected area of the workpiece surface for metallurgically heat treating the selected area of the surface, said apparatus comprising: beam generating means for generating an input high power laser beam; a laser scanner frame; a first mirror mounted on a first shaft journalled for rotation on the frame, the mirror having a reflecting surface which is tilted at a small angle from perpendicularity to the shaft; a second mirror mounted on a second shaft journalled for rotation on the frame, the second mirror having a reflecting surface which is tilted at a small angle from perpendicularity to the second shaft, said small angles being approximately equal; the first mirror being positioned in the path of the input laser beam and the second mirror being positioned in the path of the beam reflected from the first mirror, the two mirrors being so positioned that the laser beam makes approximately the same angle of incidence on each mirror; workpiece retaining means for holding a workpiece with a work surface approximately perpendicular to the reflected beam from the second mirror; rotating means attached to the frame for rotating the two mirrors at the same rotational speed and in opposite directions; and phase adjusting means attached to the frame for adjusting the relative phasing of the two mirrors, to produce a substantially straight line reciprocating resultant scan on the work surface.

Claim 17

An apparatus for scanning a laser beam onto a workpiece, comprising: beam generating means for generating an input laser beam; a laser scanner frame; a first mirror mounted on a first shaft journalled for rotation on the frame, the mirror having a reflecting surface which is tilted at a small angle from perpendicularity to the shaft; a second mirror mounted on a second shaft journalled for rotation on the frame, the second mirror having a reflecting surface which is tilted at a small angle from perpendicularity to the second shaft, said small angles being approximately equal; the first mirror being positioned in the path of the input laser beam and the second mirror being positioned in the path of the beam reflected from the first mirror, the two mirrors being so positioned that the laser beam makes approximately the same angle of incidence on each mirror; workpiece retaining means for holding a workpiece with a work surface approximately perpendicular to the reflected beam from the second mirror; means attached to the frame for rotating the two mirrors at the same rotational speed and in opposite directions; and means attached to the frame for adjusting the relative phasing of the two mirrors, to produce a substantially straight line reciprocating resultant scan on the work surface, and wherein the centers of the two mirrors and the input laser beam are in a common plane generally parallel to the work surface, with the angles of incidence at the mirrors being approximately 45°.

Claim 18

An apparatus for scanning a laser beam onto a workpiece, comprising: beam generating means for generating an input laser beam; a laser scanner frame; a first mirror mounted on a first shaft journalled for rotation on the frame, the mirror having a reflecting surface which is tilted at a small angle from perpendicularity to the shaft; a second mirror mounted on a second shaft journalled for rotation on the frame, the second mirror having a reflecting surface which is tilted at a small angle from perpendicularity to the second shaft, said small angles being approximately equal; the first mirror being positioned in the path of the input laser beam and the second mirror being positioned in the path of the beam reflected from the first mirror, the two mirrors being so positioned that the laser beam makes approximately the same angle of incidence on each mirror; workpiece retaining means for holding a workpiece with a work surface approximately perpendicular to the reflected beam from the second mirror; means attached to the frame for rotating the two mirrors at the same rotational speed and in opposite directions; and means attached to the frame for adjusting the relative phasing of the two mirrors, to produce a substantially straight line reciprocating resultant scan on the work surface, and wherein the centers of the two mirrors and the input laser beam are in a common plane generally parallel to the work surface, with the angles of incidence at the mirrors being approximately 45°.

Claim 19

An apparatus for scanning a laser beam onto a workpiece, comprising: beam generating means for generating an input laser beam; a laser scanner frame; a first mirror mounted on a first shaft journalled for rotation on the frame, the mirror having a reflecting surface which is tilted at a small angle from perpendicularity to the shaft; a second mirror mounted on a second shaft journalled for rotation on the frame, the second mirror having a reflecting surface which is tilted at a small angle from perpendicularity to the second shaft, said small angles being approximately equal; the first mirror being positioned in the path of the input laser beam and the second mirror being positioned in the path of the beam reflected from the first mirror, the two mirrors being so positioned that the laser beam makes approximately the same angle of incidence on each mirror; workpiece retaining means for holding a workpiece with a work surface approximately perpendicular to the reflected beam from the second mirror; means attached to the frame for rotating the two mirrors at the same rotational speed and in opposite directions; and wherein the means for rotating the two mirrors comprises a timing belt engaged with a series of timing pulleys, two of which are in driving engagement with the two respeceive shafts, and a motor driving another timing pulley in the series, the timing belt being positioned on the pulleys so as to rotate the surfaces of the mirrors in opposite rotational directions.

Claim 20

An apparatus for scanning a laser beam onto a workpiece, comprising: beam generating means for generating an input laser beam; a laser scanner frame; a first mirror mounted on a first shaft journalled for rotation on the frame, the mirror having a reflecting surface which is tilted at a small angle from perpendicularity to the shaft; a second mirror mounted on a second shaft journalled for rotation on the frame, the second mirror having a reflecting surface which is tilted at a small angle from perpendicularity to the second shaft, said small angles being approximately equal; the first mirror being positioned in the path of the input laser beam and the second mirror being positioned in the path of the beam reflected from the first mirror, the two mirrors being so positioned that the laser beam makes approximately the same angle of incidence on each mirror; workpiece retaining means for holding a workpiece with a work surface approximately perpendicular to the reflected beam from the second mirror; means attached to the frame for rotating the two mirrors at the same rotational speed and in opposite directions; and wherein the means for rotating the two mirrors comprises a timing belt engaged with a series of timing pulleys, two of which are in driving engagement with the two respeceive shafts, and a motor driving another timing pulley in the series, the timing belt being positioned on the pulleys so as to rotate the surfaces of the mirrors in opposite rotational directions.