Laser processing apparatus using distinct horizontal and vertical data sets

• US 7,910,869 B2
• Filed: 10/12/2005
• Issued: 03/22/2011
• Est. Priority Date: 10/13/2004
• Status: Active Grant

• Current Assignee: Ricoh Company Limited
• Original Assignee: Ricoh Company Limited
• Inventors: Seo, Manabu, Norikane, Yoshihiro, Yamada, Yasufumi
• Primary Examiner(s): Epps; Georgia Y
• Assistant Examiner(s): BENNETT, JENNIFER D
• Application Number:
  US10/582,895
• Publication Number:
  US 20090147330A1
• Time in Patent Office: 1,987 Days
• Field of Search: 250/208.1, 250/201.9, 250/550, 250/216, 250/201.8, 359/1, 359/9, 359/10, 359/11, 359/27, 359/30, 359/31, 359554-557, 348/40, 372/108, 372/18, 372/42, 372/96, 372 98-106, 349/200, 349/57, 349/74, 349/61, 349 1- 4
• US Class Current: 250/201.9
• CPC Class Codes: B23K 26/066 by using masks
• CPC Class Codes: B23K 26/38 by boring or cutting
• CPC Class Codes: G03H 1/0808 Methods of numerical synthesis, e.g. coherent ray tracing [CRT], diffraction specific
• CPC Class Codes: G03H 1/0891 Processes or apparatus adapted to convert digital holographic data into a hologram G03H1/2294 takes precedence
• CPC Class Codes: G03H 1/2249 Holobject properties
• CPC Class Codes: G03H 1/2286 Particular reconstruction light G03H1/24 takes precedence; Beam properties
• CPC Class Codes: G03H 1/2294 Addressing the hologram to an active spatial light modulator
• CPC Class Codes: G03H 2001/0066 for wavefront matching wherein the hologram is arranged to convert a predetermined wavefront into a comprehensive wave, e.g. associative memory recognition using holographic masks G06V10/88
• CPC Class Codes: G03H 2001/0094 for patterning or machining using the holobject as input light distribution microlithography G03F7/70283
• CPC Class Codes: G03H 2001/048 Parallel printer, i.e. a fringe pattern is reproduced
• CPC Class Codes: G03H 2001/0484 Arranged to produce three-dimensional fringe pattern
• CPC Class Codes: G03H 2001/0491 by monitoring the hologram formation, e.g. via a feed-back loop
• CPC Class Codes: G03H 2001/221 Element having optical power, e.g. field lens
• CPC Class Codes: G03H 2001/2244 Means for detecting or recording the holobject
• CPC Class Codes: G03H 2001/2255 Holobject out of Fourier or hologram planes
• CPC Class Codes: G03H 2210/30 3D object
• CPC Class Codes: G03H 2222/33 Pulsed light beam
• CPC Class Codes: G03H 2222/35 Transverse intensity distribution of the light beam
• CPC Class Codes: G03H 2225/32 Phase only
• CPC Class Codes: G03H 2240/42 Discrete level

Abstract

A laser processing apparatus includes a laser source (11), a spatial phase modulator (13) configured to modulate a phase of a laser beam emitted from the laser source, a synthetic data generator (17) configured to generate synthetic data by combining hologram image data representing a pattern image to be processed with position displacement hologram data for shifting the pattern image to a prescribed position, the synthetic data being input to the spatial phase modulator for the phase modulation of the laser beams, and a focusing optical unit (14) configured to guide the phase-modulated laser beam onto a surface to be processed to reproduce the pattern image on the processed surface.

Claims

1. A laser processing apparatus, comprising:

a laser source;

a spatial phase modulator configured to modulate a phase of a laser beam emitted from the laser source;

a focusing optical unit configured to guide the phase-modulated laser beam onto a surface to be processed to reproduce a pattern image on the processed surface;

a computer configured to calculate separately a horizontal hologram data set representing displacement of the pattern image in a direction parallel to the processed surface and a vertical hologram data set representing displacement of the pattern image in a direction perpendicular to the processed surface, the horizontal hologram data set and the vertical hologram data set being distinct from each other; and

a synthetic data generator configured to generate synthetic data by combining hologram image data representing the pattern image to be processed with position displacement hologram data for shifting the pattern image to a prescribed position, said position displacement hologram data including either the horizontal hologram data set, the vertical hologram data set, or a combination of the horizontal and vertical hologram data sets, said synthetic data being input to the spatial phase modulator for the phase modulation of the laser beams.

2. The laser processing apparatus of claim 1, wherein the horizontal hologram data set has substantially a sawtooth phase distribution profile.

3. The laser processing apparatus of claim 1, wherein the vertical hologram data set has a phase distribution profile similar to a Fresnel zone plate.

4. The laser processing apparatus of claim 3, wherein a distance from the spatial phase modulator to the focusing optical unit is equal to a focal length of the focusing optical unit.

5. The laser processing apparatus of claim 1, further comprising:

a wavefront measuring unit configured to measure a wavefront of the laser beam input to the spatial phase generator,

wherein the synthetic data generator generates correction data for correcting distortion of the wavefront of the laser beam detected by the wavefront measuring unit, and the correction data are supplied to the spatial phase modulator.

6. The laser processing apparatus of claim 1, further comprising at least one of:

an irradiation time adjusting unit configured to regulate irradiation time of the laser beam; and

a beam intensity adjusting unit configured to regulate an intensity of the laser beam.

7. The laser processing apparatus of claim 1, further comprising:

a horizontal-direction position detector configured to detect a horizontal position in a plane parallel to the processed surface,

wherein the synthetic data generator generates the horizontal hologram data set based on the detection result.

8. The laser processing apparatus of claim 7, wherein the horizontal-direction position detector detects a reference pattern formed on the processed surface.

9. The laser processing apparatus of claim 1, further comprising:

a first driving unit configured to move a light spot of the laser beam relative to the processed surface in a direction parallel to the processed surface.

10. The laser processing apparatus of claim 1, further comprising:

a vertical-direction position detector configured to detect a positional relation between the focusing optical unit and the processed surface in a direction perpendicular to the processed surface,

wherein the synthetic data generator generates the vertical hologram data set based on the detection result.

11. The laser processing apparatus of claim 1, further comprising:

a second driving unit configured to move a position of the processed surface relative to the focusing optical unit in a direction perpendicular to the processed surface.

12. The laser processing apparatus of claim 1, wherein the laser source is an ultra-short pulse laser source with a pulse width at or below several picoseconds.

18. The laser processing apparatus of claim 1, wherein the combination of the horizontal hologram data set and the vertical hologram data set includes adding the horizontal hologram data set and the vertical hologram data set together.

13. A laser processing method, comprising:

calculating hologram image data representing a pattern image to be processed on a object;

generating position displacement data for shifting the pattern image to a prescribed position with respect to a processed surface of the object;

combining the hologram image data with the position displacement data to produce synthetic hologram data;

modulating a phase of a laser beam using the synthetic hologram data; and

guiding the phase-modulated laser beam onto the processed surface using an optical system,

wherein said position displacement data includes either a horizontal hologram data set representing displacement in a direction parallel to the processed surface, a vertical hologram data set representing displacement in a direction perpendicular to the processed surface, or a combination of the horizontal and vertical hologram data sets, and

wherein the horizontal data set and the vertical data set are distinct from each other and calculated separately.

14. The laser processing method of claim 13, further comprising:

setting a distance between a phase modulating position and the optical system equal to a focal length of the optical system.

15. A computer readable storage medium encoded with a computer readable program configured to cause an information processing apparatus to execute a method, the method comprising:

calculating hologram image representing a pattern image to be processed on an object;

generating position displacement data for shifting the pattern image to a prescribed position with respect to a processed surface of the object;

combining the hologram image data with the position displacement data to produce synthetic hologram data; and

inputting the synthetic hologram data to a phase modulator to control phase modulation performed on a laser beam,

wherein said position displacement data includes either a horizontal hologram data set representing displacement in a direction parallel to the processed surface, a vertical hologram data set representing displacement in a direction perpendicular to the processed surface, or a combination of the horizontal and vertical hologram data sets, and

wherein the horizontal data set and the vertical data set are distinct from each other and calculated separately.

16. The computer readable storage medium of claim 15, wherein the horizontal hologram data set has substantially a sawtooth phase distribution profile.

17. The computer readable storage medium of claim 15, wherein the vertical hologram data set has a phase distribution similar to a Fresnel zone plate.