Laser machining device

• US 6,710,292 B2
• Filed: 07/18/2002
• Issued: 03/23/2004
• Est. Priority Date: 01/19/2000
• Status: Expired due to Term

• Current Assignee: Hamamatsu Photonics KK
• Original Assignee: Hamamatsu Photonics KK
• Inventors: Igasaki, Yasunori, Hara, Tsutomu, Fukuchi, Norihiro, Hiruma, Teruo
• Primary Examiner(s): Heinrich, Samuel M
• Application Number:
  US10/181,376
• Publication Number:
  US 20030010763A1
• Time in Patent Office: 614 Days
• Field of Search: 219/121.6, 219/121.65, 219/121.67, 219/121.68, 219/121.7, 219/121.73, 219/121.75
• US Class Current: 219/121.73
• CPC Class Codes: B23K 26/0006 taking account of the properties of the material involved B23K26/32, B23K26/40 take precedence
• CPC Class Codes: B23K 26/064 by means of optical elements, e.g. lenses, mirrors or prisms
• CPC Class Codes: B23K 26/066 by using masks
• CPC Class Codes: B23K 26/359 by providing a line or line pattern, e.g. a dotted break initiation line
• CPC Class Codes: G02B 27/46 Systems using spatial filters
• CPC Class Codes: G02F 1/135 Liquid crystal cells structurally associated with a photoconducting or a ferro-electric layer, the properties of which can be optically or electrically varied G02F1/133348 takes precedence
• CPC Class Codes: G03H 1/2294 Addressing the hologram to an active spatial light modulator
• CPC Class Codes: G03H 2001/0094 for patterning or machining using the holobject as input light distribution microlithography G03F7/70283
• CPC Class Codes: G03H 2001/0491 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 2001/2213 Diffusing screen revealing the real holobject, e.g. container filed with gel to reveal the 3D holobject
• CPC Class Codes: G03H 2001/2244 Means for detecting or recording the holobject
• CPC Class Codes: G03H 2210/441 Numerical processing applied to the object data other than numerical propagation synthesizing propagation G03H1/0808
• CPC Class Codes: G03H 2223/12 Amplitude mask, e.g. diaphragm, Louver filter
• CPC Class Codes: G03H 2223/55 Arranged at a Fourier plane
• CPC Class Codes: G03H 2225/25 Optically addressed SLM [OA-SLM]
• CPC Class Codes: G03H 2225/32 Phase only
• CPC Class Codes: G03H 2225/52 Reflective modulator

Abstract

This invention relates to a laser beam machining apparatus equipped with a spatial light modulator. The laser beam machining apparatus according to this invention comprises a reflection-type spatial light modulator, hologram pattern writing means for writing onto said reflection-type spatial light modulator a hologram pattern corresponding to the desired optical image intended to be irradiated onto a target, laser beam irradiating means for irradiating readout light onto said reflection-type spatial light modulator at an incidence angle θ, and a Fourier lens for performing a Fourier transform of said readout light, phase modulated by said reflection-type spatial light modulator. Through use of this laser beam machining apparatus, improvement in utilization efficiency of the readout light and improvement in the level of freedom in machining patterns can be expected.

Claims

1. A laser beam machining apparatus comprising:

a reflection-type spatial light modulator;

hologram pattern writing means for writing onto said reflection-type spatial light modulator a hologram pattern corresponding to the desired optical image intended to be irradiated onto a target;

laser beam irradiating means for irradiating a readout light onto said reflection-type spatial light modulator at an incidence angle θ

; and

a Fourier lens for performing a Fourier transform of said readout light, phase modulated by said reflection-type spatial light modulator.

2. The laser beam machining apparatus according to claim 1, wherein said laser beam irradiating means is provided on an incident beam axis inclined by said incidence angle θ

relative to a line normal to the incidence plane irradiated by said readout light of said reflection-type spatial light modulator and said Fourier lens is placed on a reflected beam axis inclined by reflection angle φ

(=θ

) relative to said normal line within a plane including said normal line and said incident beam axis.

3. The laser beam machining apparatus according to claim 1, further comprising a stage for positioning said target.

4. The laser beam machining apparatus according to claim 1, wherein said hologram pattern writing means comprises storage means for storing said hologram pattern corresponding to said desired optical image to be irradiated onto said target.

5. The laser beam machining apparatus according to claim 1, wherein said hologram pattern writing means has a structure such that a hologram pattern corresponding to a corrected image, that is obtained by modifying said desired optical image by a factor of 1/cosθ

in a specified direction, can be written onto said reflection-type spatial light modulator when said desired optical image is irradiated onto said target.

6. The laser beam machining apparatus according to claim 1, further comprising a masking means placed on the light path of said readout light, from said Fourier lens to said target, for cutting zero-order light.

7. The laser beam machining apparatus according to claim 1, further comprising an imaging lens for imaging said readout light, Fourier transformed by said Fourier lens, on a specified surface of said target, and masking means placed on the light path of said readout light that extends from said Fourier lens to said target, for cutting zero-order light.

8. The laser beam machining apparatus according to claim 1, further comprising object position recognizing means for acquiring position information on said target, wherein said hologram pattern writing means has a structure enabling generation of a hologram pattern matched to the position of said target, based on position information on said target acquired by said object position recognizing means.

9. The laser beam machining apparatus according to claim 1, further comprising physical body shape recognizing means for acquiring 3-dimensional information on said target, wherein said hologram pattern writing means has a structure enabling generation of a hologram pattern matched to the shape of said target, based on 3-dimensional information on said target acquired by said physical body shape recognizing means.