Laser beam delivery system with trepanning module

• US 20020196534A1
• Filed: 06/04/2002
• Published: 12/26/2002
• Est. Priority Date: 06/19/2001
• Status: Active Grant

• Current Assignee: Hitachi VIA Mechanics Limited (Hitachi, Ltd.)
• Original Assignee: Hitachi VIA Mechanics Limited (Hitachi, Ltd.)
• Inventors: Ohar, Orest, Lizotte, Todd E.
• Granted Patent: US 6,804,269 B2
• Time in Patent Office: Days
• US Class Current: 359/362
• CPC Class Codes: B23K 26/0608 in the same heat affected zone [HAZ] B23K26/0613, B23K26/0619 take precedence
• CPC Class Codes: B23K 26/066 by using masks
• CPC Class Codes: B23K 26/067 Dividing the beam into multiple beams, e.g. multifocusing
• CPC Class Codes: B23K 26/08 Devices involving relative movement between laser beam and workpiece
• CPC Class Codes: B23K 26/082 Scanning systems, i.e. devices involving movement of the laser beam relative to the laser head
• CPC Class Codes: B23K 26/389 of fluid openings, e.g. nozzles, jets laser machining of inkjet nozzles B41J2/1634
• CPC Class Codes: G02B 26/123 Multibeam scanners, e.g. using multiple light sources or beam splitters
• CPC Class Codes: G02B 27/106 for splitting or combining a plurality of identical beams or images, e.g. image replication
• CPC Class Codes: G02B 27/1093 for use with monochromatic radiation only, e.g. devices for splitting a single laser source
• CPC Class Codes: G02B 27/144 using partially transparent surfaces without spectral selectivity G02B27/147 takes precedence
• CPC Class Codes: G02B 27/145 having sequential partially reflecting surfaces
• CPC Class Codes: G02B 5/32 Holograms used as optical elements
• CPC Class Codes: H01S 3/10 Controlling the intensity, frequency, phase, polarisation or direction of the emitted radiation, e.g. switching, gating, modulating or demodulating

Abstract

A laser beam delivery system for supplying a laser beam to a computer generated hologram which shapes and divides the supplied laser beam into a plurality of pseudo flat top laser beams. The plurality of pseudo flat top laser beams are then passed through collimated optics which alter the beams so that the beams are conveyed along the optical axis in a parallel manner. The plurality of collimated laser beams then passes through a converging mechanism which facilitates converging of the plurality of separated collimated laser beams through a clear aperture of a mirror of a first repeat positioning device so that all of the light is received by the repeat positioning device and appropriately reflected thereby to a second mirror of a second repeat positioning device and then to a rear surface of an F-Theta lens. The F-Theta lens focuses the plurality of separated collimated laser beams at the object to be processed. The converging mechanism facilitates converging of all of the supplied light so that substantially all of the supplied light passes through the clear aperture(s) of the repeat positioning device(s).

Claims

1. A laser beam delivery system comprising:

a laser source for outputting a laser beam;

a shaping apparatus for receiving the laser beam output by the laser and for shaping the laser beam into a plurality of separate laser beams;

a converging mechanism for redirecting the plurality of separate laser beams through a clear aperture of a mirror of a repeat positioning device;

the repeat positioning device redirecting the plurality of separate laser beams to an F-Theta lens; and

the F-Theta lens focusing the plurality of separate laser beams at an object to be processed.

2. The laser beam delivery system according to claim 1, wherein the shaping apparatus comprises a computer generated hologram and the computer generated hologram splits the light laser beam at an image plane into at least three separate laser beams.

3. The laser beam delivery system according to claim 2, wherein collimated optics are located adjacent to the imaging plane for collimating the three separate laser beams generated by the computer generated hologram so that the three separate laser beams are supplied parallel to one another and along an optical axis of the laser beam delivery system.

4. The laser beam delivery system according to claim 3, wherein an illumination prism is located between the collimated optics and the mirror of the repeat positioning device so that the three separate laser beams converge toward one another as the three separate laser beams approaching the repeat positioning device so that all of the generated light passes through a clear aperture of the repeat positioning device.

5. The laser beam delivery system according to claim 1, wherein two repeat positioning devices are provided for redirecting the plurality of separate laser beams at the F-Theta lens and the object to be processed.

6. The laser beam delivery system according to claim 1, wherein the F-Theta lens is located between the two repeat positioning devices and the object to be processed, and the F-Theta lens is positioned a sufficient distance from the object to be processed so that the laser beam of each of the plurality of separate laser beams is focused prior to contacting the object to be processed.

7. The laser beam delivery system according to claim 1, wherein the F-Theta lens is located between the two repeat positioning devices and the object to be processed, and the object to be processed is positioned at a focal plane of the F-Theta lens.

8. The laser beam delivery system according to claim 1, wherein the laser beam has a gaussian profile and the computer generated hologram converts the laser beam of the guassian profile into three separate beams each having a substantially flat top portion profile.

9. The laser beam delivery system according to claim 1, wherein the converging mechanism comprises an illumination prism connected to a drive and the drive facilitates conveyance of the illumination prism to and fro along the optical axis to facilitate adjustment of a degree of convergence of the plurality of separate laser beams through the clear aperture of the mirror of the repeat positioning device.

10. The laser beam delivery system according to claim 9, wherein the illumination prism has a pair of opposed planar surfaces which extend normal to the longitudinal axis of the laser beam delivery system and a pair of inclined surfaces which extend at an acute angle with respect to the optical axis of the system to facilitate converging of the laser beams through the clear aperture of the mirror of the repeat positioning device.

11. The laser beam delivery system according to claim 2, wherein a pair of prisms facilitates convergence of two of the three separate laser beams toward a central beam so that the three separate laser beams pass through a clear aperture of the repeat positioning device, and the pair of prisms is movable to and fro along the optical axis to facilitate adjustment of a degree of convergence of the plurality of separate laser beams.

12. The laser beam delivery system according to claim 11, wherein the pair of prisms is also rotatable about a rotation axis to facilitate adjustment of the degree of convergence of the plurality of separate laser beams.

13. The laser beam delivery system according to claim 2, wherein a pair of deflective mirrors facilitates convergence of two of the three separate laser beams toward a central beam so that the three separate laser beams pass through a clear aperture of a first mirror of the repeat positioning device, and the pair of deflective mirrors is movable to and fro along the optical axis to facilitate adjustment of a degree of convergence of the plurality of separate laser beams.

14. The laser beam delivery system according to claim 1, wherein the laser is directed at a series of beam splitters, and the series of partially reflected beam splitters reflect a portion of the supplied laser beam parallel to the optical axis of the laser beam delivery system while allowing a remaining portion of the supplied laser beam to pass therethrough.

15. The laser beam delivery system according to claim 1, wherein the laser beam is supplied to a beam splitter device and the beam splitter device splits the supplied laser beam into at least three separate laser beams which are supplied parallel to the optical axis of the delivery system beam, and the beam splitter device has partially reflective surfaces, which allow a portion of the laser beam to pass therethrough and reflect a remaining portion of the supplied laser beam.

16. The laser beam delivery system according to claim 1, wherein a hologram, first and second illumination prisms and three individual shutters are all supported by and housed within a rotatable module, and a rotational drive is connected to the rotatable module to facilitate rotation of the rotatable module relative to the optical axis.

17. The laser beam delivery system according to claim 1, wherein the laser beam delivery system has a spreader module, for spacing two outer beams radially with respect to a central beam, and an adjustment mechanism facilitates spacing of the first pair of prisms from the second pair of prisms to control spacing of the two outer beams relative to the central beam.

18. The laser beam delivery system according to claim 17, wherein the adjustment mechanism also includes a rotation mechanism to rotate each prism about a rotational axis thereof and assist with controlling spacing of the two outer beams relative to the central beam.

19. The laser beam delivery system according to claim 1, wherein the laser beam delivery system has a spreader module, for spacing two outer beams radially with respect to a central beam, and an adjustment mechanism facilitates spacing of the first pair of prisms from the second pair of prisms to control an amount of spacing of the two outer beams relative to the central beam, and the spreader module and the adjustment mechanism are housed within a rotatable module, and a rotational drive is connected to the rotatable module to facilitate rotation of the rotatable module relative to the optical axis.

20. The laser beam delivery system according to claim 1, wherein the laser beam delivery system has a trepanning module positioned between the converging mechanism and the repeat positioning device, the trepanning module comprises first and second spaced apart sequentially arranged rotating wedge prisms which are aligned along and are concentric with the optical axis of the laser beam delivery system.