Method and apparatus for dot matrix writing using a continous wave laser

An apparatus for marking a target by exposing the target to continuous wave laser radiation, including:

• a means for generating a continuous wave laser beam;
• an optical element;
• a rotating mirror;
• a means for projecting the laser beam onto a first point which coincides with a surface of the rotating mirror to produce a reflected beam which propagates away from the rotating mirror, and for scanning the reflected beam across the optical element to produce an output beam which forms a real image of the first point at a stationary image point, wherein a cross-section of the output beam near the real image moves only a short distance during a dwell time, determined by a rotational velocity of the rotating mirror, which can be made sufficiently long to directly mark the target without need for a light sensitive surface or photographic process;
• a target positioned relative to the optical element in such a position that the optical element projects a line of laser radiation on the target for said dwell time when the reflected beam is scanned across the optical element;
• and
• control means, connected to the rotating mirror, for controlling the rotational velocity to control the dwell time.

A system for directly marking information on a target surface in a pattern of dots, wherein the dots are arranged to form columns of dot matrix alpha-numeric characters, including:

• a laser which emits a beam of radiation;
• means for moving the target surface relative to the laser in a direction substantially perpendicular to the columns;
• means for modulating the beam to mark on the target surface, or omit, individual ones of the dots selectively to generate alpha-numeric characters, wherein a projection of the beam at each of the dots remains stationary for a dwell time which can be made sufficiently long to directly mark the target surface without need for a light sensitive surface or photographic process;
• means for scanning the beam from a rotating polygonal mirror having facets and an angular velocity, across an array of concave spherical mirrors, so that reflection of the beam from said concave spherical mirrors produces a real image, on the target surface for each of the dots, of a point at which the beam is incident on one of the facets;
• and
• means for controlling the dwell time for marking each of the dots on the target surface to match characteristics of said target surface, by varying the angular velocity.

A system for directly marking information on a target surface in a pattern of lines, wherein the lines are arranged to form columns of dot matrix alpha-numeric characters, including:

• a laser which emits a beam of radiation;
• means for moving the target surface relative to the laser in a direction substantially perpendicular to the columns;
• means for modulating a beam of radiation emitted by the laser to selectively mark full lines or shortened lines on the target surface, or omit individual ones of the lines, thereby generating the alpha-numeric characters;
• means for scanning the beam from a rotating polygonal mirror having facets and an angular velocity, across a lens system, so that the beam transmitted through the lens system produces a real image of a point at which the beam is incident on one of the facets, wherein a cross-section of the beam near the real image moves only a short distance during a dwell time which can be made sufficiently long to directly mark the target surface without need for a light sensitive surface or photographic process;
• and
• means for controlling the dwell time for marking each of the lines on the target surface to match characteristics of said target surface, by varying the angular velocity.

A system for directly marking information on a target surface in a pattern of lines, wherein the lines are arranged in columns, including:

• a laser which emits a beam of radiation;
• means for moving the target surface relative to the laser in a direction substantially perpendicular to the columns;
• means for modulating a beam of radiation emitted by the laser to selectively mark full lines or shortened lines on the target surface, or omit individual ones of the lines, thereby generating selected arrangements of lines;
• means for scanning the beam from a rotating polygonal mirror having facets and an angular velocity, across an optical element, so that the optical element produces a real image of a point at which the beam is incident on one of the facets, wherein a cross-section of the beam near the real image moves only a short distance during a dwell time which can be made sufficiently long to directly mark the target surface without need for a light sensitive surface or photographic process;
• and
• means for controlling the dwell time for marking each of the lines on the target surface to match characteristics of said target surface, by varying the angular velocity.

A method for marking a target by exposing the target to continuous wave laser radiation, including the steps of:

• (a) projecting a continuous wave laser beam onto a first point which coincides with a surface of a rotating mirror to produce a reflected beam which propagates away from the rotating mirror;
• (b) during step (a), scanning the reflected beam across an optical element to produce an output beam which forms a real image of the first point at a stationary image point, wherein a cross-section of the output beam near the real image moves only a short distance during a dwell time, determined by a rotational velocity of the rotating mirror, which can be made sufficiently long to directly mark the target without need for a light sensitive surface or photographic process;
• and
• (c) positioning the target relative to the optical element so that, during step (b), the optical element projects a line of laser radiation on the target, wherein the optical element projects the line on the target for said dwell time, and also including the step of:
• controlling the rotational velocity to control the dwell time.

A method for marking a target by exposing the target to continuous wave laser radiation, including the steps of:

• (a) projecting a continuous wave laser beam onto a first point which coincides with a surface of a rotating polygonal mirror having reflective facets to produce a reflected beam which propagates away from the rotating polygonal mirror;
• (b) during step (a), scanning the reflected beam across a lens system to produce an output beam which forms a real image of the first point at a stationary image point, where the stationary image point is a first distance from said lens system, and wherein a reflected beam from each of the facets scans across the lens system as the polygonal mirror rotates;
• and
• (c) positioning the target a second distance away from the lens system so that, during step (b), the lens system projects a line of laser radiation on the target, wherein the difference between the first distance and the second distance is much shorter than the first distance, wherein each said reflected beam is re-reflected from a secondary array of mirrors, and then scans at least twice across the lens system as the polygonal mirror rotates.

A method for marking a target by exposing the target to continuous wave laser radiation, including the steps of:

• (a) projecting a continuous wave laser beam onto a first point which coincides with a surface of a rotating mirror to produce a reflected beam which propagates away from the rotating mirror;
• (b) during step (a), scanning the reflected beam across a lens system to produce an output beam which forms a real image of the first point at a stationary image point, where the stationary image point is a first distance from said lens system;
• and
• (c) positioning the target a second distance away from the lens system so that, during step (b), the lens system projects a line of laser radiation on the target, wherein the difference between the first distance and the second distance is much shorter than the first distance, wherein the lens system projects the line on the target for a dwell time determined by a rotational velocity of the rotating mirror, and also including the step of:
• controlling the rotational velocity to control the dwell time.

A method for directly marking information on a target surface in a pattern of dots using a laser, wherein the dots are arranged in columns to form dot matrix alpha-numeric characters and the target surface moves in a direction substantially perpendicular to the columns, the method including the steps of:

• (a) scanning the beam from a rotating polygonal mirror having facets and an angular velocity, across an array of concave spherical mirrors, so that reflection of the beam from said concave spherical mirrors projects a real image, on the target surface for each of the dots, of a point at which the beam is incident on one of the facets;
• (b) while performing step (a), modulating a beam of radiation emitted by the laser to mark on the target surface, or omit, individual ones of the dots selectively to generate alpha-numeric characters, wherein a projection of the beam at each of the dots remains stationary for a dwell time which can be made sufficiently long to directly mark the target surface without need for a light sensitive surface or photographic process;
• and
• (c) controlling the dwell time for marking each of the dots on the target surface to match characteristics of said target surface, by varying the angular velocity.

A method for directly marking information on a target surface in a pattern of dots using a laser, wherein the dots are arranged in columns and the target surface moves in a direction substantially perpendicular to the columns, the method including the steps of:

• (a) scanning the beam from a rotating polygonal mirror having facets and an angular velocity, across an optical element, so that the optical element projects a real image, on the target surface for each of the dots, of a point at which the beam is incident on one of the facets;
• (b) while performing step (a), modulating a beam of radiation emitted by the laser to mark on the target surface, or omit, individual ones of the dots selectively to generate selected arrangements of dots, wherein a projection of the beam at each of the dots remains stationary for a dwell time which can be made sufficiently long to directly mark the target surface without need for a light sensitive surface or photographic process;
• and
• (c) controlling the dwell time for marking each of the dots on the target surface to match characteristics of said target surface, by varying the angular velocity.

A system for directly marking information on a target surface in a pattern of dots, wherein the dots are arranged in columns, including:

• a laser which emits a beam of radiation;
• means for moving the target surface relative to the laser in a direction substantially perpendicular to the columns;
• means for modulating the beam to mark on the target surface, or omit, individual ones of the dots selectively to generate selected arrangements of dots, wherein a projection of the beam at each of the dots remains stationary for a dwell time which can be made sufficiently long to directly mark the target surface without need for a light sensitive surface or photographic process;
• means for scanning the beam from a rotating polygonal mirror having facets and an angular velocity, across an optical element, so that the optical element projects a real image, on the target surface for each of the dots, of a point at which the beam is incident on one of the facets;
• and
• means for controlling the dwell time for marking each of the dots on the target surface to match characteristics of said target surface, by varying the angular velocity.

A method for directly marking information on a target surface in a pattern of lines using a laser, wherein the lines are arranged to form columns of dot matrix alpha-numeric characters and the target surface moves in a direction substantially perpendicular to the columns, the method including the steps of:

• (a) modulating a beam of radiation emitted by the laser to selectively mark full lines or shortened lines on the target surface, or omit individual ones of the lines, thereby generating the alpha-numeric characters;
• (b) while performing step (a), scanning the beam from a rotating polygonal mirror having facets and an angular velocity, across a lens system, so that the beam transmitted through the lens system produces a real image of a point at which the beam is incident on one of the facets, wherein a cross-section of the beam near the real image moves only a short distance during a dwell time which can be made sufficiently long to directly mark the target surface without need for a light sensitive surface or photographic process;
• and
• (c) controlling the dwell time for marking each of the lines on the target surface to match characteristics of said target surface, by varying the angular velocity.

A method for directly marking information on a target surface in a pattern of lines using a laser, wherein the lines are arranged in columns and the target surface moves in a direction substantially perpendicular to the columns, the method including the steps of:

• (a) modulating a beam of radiation emitted by the laser to selectively mark full lines or shortened lines on the target surface, or omit individual ones of the lines, thereby generating selected arrangements of lines;
• (b) while performing step (a), scanning the beam from a rotating polygonal mirror having facets and an angular velocity, across an optical element, so that the optical element produces a real image of a point at which the beam is incident on one of the facets, wherein a cross-section of the beam near the real image moves only a short distance during a dwell time which can be made sufficiently long to directly mark the target surface without need for a light sensitive surface or photographic process;
• and
• (c) controlling the dwell time for marking each of the lines on the target surface to match characteristics of said target surface, by varying the angular velocity.