Laser emitting apparatus using a basic hologram and a focusing hologram

• US 8,941,903 B2
• Filed: 06/14/2013
• Issued: 01/27/2015
• Est. Priority Date: 10/01/2008
• Status: Active Grant

• Current Assignee: Hamamatsu Photonics KK
• Original Assignee: Hamamatsu Photonics KK
• Inventors: Takiguchi, Yuu, Matsumoto, Naoya, Fukuchi, Norihiro, Inoue, Takashi, Takemori, Tamiki, Mukozaka, Naohisa
• Primary Examiner(s): Chapel, Derek S
• Application Number:
  US13/918,225
• Publication Number:
  US 20130286453A1
• Time in Patent Office: 592 Days
• Field of Search: None
• US Class Current: 359/9
• CPC Class Codes: B23K 26/06 Shaping the laser beam, e.g. by masks or multi-focusing
• CPC Class Codes: B23K 26/352 for surface treatment
• CPC Class Codes: G02B 13/22 Telecentric objectives or lens systems
• CPC Class Codes: G02B 3/08 with discontinuous faces, e.g. Fresnel lens diffractive Fresnel lenses G02B5/1876
• CPC Class Codes: G02B 5/32 Holograms used as optical elements
• CPC Class Codes: G03H 1/0005 Adaptation of holography to specific applications holographic optical element G02B5/32; holographic scanner G02B26/106; recognition using holographic mask G06V10/88; holographic memories G11B7/0065, G11C13/042
• CPC Class Codes: G03H 1/08 Synthesising holograms, i.e. holograms synthesized from objects or objects from hologramsusing electric digital computers G06F; G06T
• CPC Class Codes: G03H 1/0808 Methods of numerical synthesis, e.g. coherent ray tracing [CRT], diffraction specific
• 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 2225/32 Phase only
• CPC Class Codes: H01S 3/0085 Modulating the output, i.e. the laser beam is modulated outside the laser cavity

Abstract

A laser processing apparatus including a laser light source, a phase modulation type spatial light modulator, a driving unit, a control unit, and an imaging optical system. A storage unit that is included in the driving unit stores a plurality of basic holograms corresponding to a plurality of basic processing patterns and a focusing hologram corresponding to a Fresnel lens pattern. The control unit arranges in parallel two or more basic holograms selected from the plurality of basic holograms stored in the storage unit, overlaps the focusing hologram with each of the basic holograms arranged in parallel to form the whole hologram, and presents the formed whole hologram to the spatial light modulator.

Claims

1. An apparatus for illuminating light to a target with a basic pattern, comprising:

a light source configured to output light;

a spatial light modulator configured to present a hologram for modulating the outputted; and

an imaging optical system that receives the light output from the spatial light modulator and is configured to illuminate the modulated light on the target to form the basic pattern;

wherein the imaging optical system includes a telocentric optical system, and

wherein the hologram of the spatial light modulator is formed by overlapping a focusing hologram and a basic hologram corresponding to the basic pattern.

2. The apparatus of claim 1, wherein the telecentric optical system is arranged such that a focusing relationship in a focal length of the focusing hologram is established.

3. The apparatus of claim 2, further comprising:

a storage unit that stores a plurality of the focusing holograms corresponding to a plurality of Fresnel lens patterns having different focal lengths.

4. The apparatus of claim 2, wherein the focusing hologram corresponds to a Fresnel lens pattern.

5. The apparatus of claim 1, wherein an imaging position and an imaging magnification of the imaging optical system are variable.

6. The apparatus of claim 1, further comprising:

a control unit for controlling the overlapping of the focusing hologram with the basic hologram,

wherein the control unit controls a focal length of the focusing hologram that overlaps the basic hologram and an imaging position of the imaging optical system so as to be associated with each other.

7. The apparatus of claim 1, wherein a size of the basic pattern on the target is adjusted by preparing a plurality of the focusing holograms having different focal lengths and changing a focal length of the focusing hologram overlapped with the basic pattern.

8. The apparatus of claim 1, wherein an imaging position and an imaging magnification of the imaging optical system are adjusted when an imaging position on a surface of the spatial light modulator is changed.

9. The apparatus of claim 1, wherein a size of the overlapped focusing hologram and basic hologram of the target is changed by changing at least on of an enlargement ratio and a reduction ratio of the imaging optical system.

10. The apparatus of claim 1, wherein the focusing hologram is inscribed inside a corresponding basic hologram.

11. The apparatus of claim 1, wherein random phase modulation is performed in a region in which the basic hologram and the focusing hologram do not overlap each other, and in a region having neither the basic hologram nor the focusing hologram.

12. An apparatus for processing the target comprising the emitting apparatus of claim 1.

13. The apparatus of claim 1, wherein the spatial light modulator is a phase modulation type spatial light modulator.

14. The apparatus of claim 1, wherein the light is a laser light.

15. The apparatus of claim 1, wherein a size of the basic pattern on the target is adjusted by changing a focal length of the focusing hologram.

16. A method for illuminating a basic pattern onto a target, the method comprising:

emitting a light from a light source;

modulating the emitted light by a spatial light modulator having a hologram, the hologram being formed by overlapping a focusing hologram and the basic hologram corresponding to the basic pattern; and

receiving the modulated light at an imaging optical system and illuminating the modulated light onto the target to form a basic pattern, the imaging optical system having a telecentric optical system.

17. The method of claim 16, further comprising:

establishing a focusing relationship in a focal length of the focusing hologram by the telecentric optical system.

18. The method of claim 17, further comprising:

storing a plurality of the focusing holograms corresponding to a plurality of Fresnel lens patterns having different focal lengths in a storage unit.

19. The method of claim 17, wherein the focusing hologram corresponds to a Fresnel lens pattern.

20. The method of claim 16, further comprising:

varying an imaging position and an imaging magnification of the imaging optical system.

21. The method of claim 16, further comprising:

controlling the overlapping of the focusing hologram with the basic hologram by a control unit, by controlling a focal length of the focusing hologram that overlaps the basic hologram and an imaging position of the imaging optical system so as to be associated with each other.

22. The method of claim 16, further comprising:

adjusting a size of the basic pattern on the target by preparing a plurality of the focusing holograms having different focal lengths and changing a focal length of the focusing hologram overlapped with the basic pattern.

23. The method of claim 16, further comprising:

adjusting an imaging position and an imaging magnification of the imaging optical system when an imaging position on a surface of the spatial light modulator is changed.

24. The method of claim 16, further comprising:

changing a size of the overlapped focusing hologram and basic hologram of the target by varying at least on of an enlargement ratio and a. reduction ratio of the imaging optical system.

25. The method of claim 16, wherein the spatial light modulator is a phase modulation type spatial light modulator.

26. The method of claim 16, wherein the step of emitting emits a laser light.

27. The method of claim 16, further comprising:

adjusting a size of the basic pattern on the target by changing a focal length of the focusing hologram.