Beam generating apparatus

• US 8,780,446 B2
• Filed: 03/12/2013
• Issued: 07/15/2014
• Est. Priority Date: 12/17/2012
• Status: Active Grant

• Current Assignee: Industrial Technology Research Institute
• Original Assignee: Industrial Technology Research Institute
• Inventors: Chen, Cheng-Huan, Liu, Sung-Ho, Lee, Min-Kai, Lin, Yu-Chung
• Primary Examiner(s): Jones, James
• Application Number:
  US13/794,812
• Publication Number:
  US 20140168780A1
• Time in Patent Office: 490 Days
• Field of Search: 359/626
• US Class Current: 359/626
• CPC Class Codes: G02B 27/48 Laser speckle optics
• CPC Class Codes: G02B 3/005 arranged along a single direction only, e.g. lenticular sheets G02B3/0043 takes precedence

Abstract

A beam generating apparatus includes a laser light source, a speckle suppressing module, a light homogenizing module and a driving unit. The laser light source outputs a laser beam. The speckle suppressing module includes two biconic lenses and a diffuser. The first biconic lens is disposed on a transmission path of the laser beam. The diffuser is located on the transmission path of the laser beam between the first and second biconic lenses. The light homogenizing module is disposed on the transmission path of the laser beam from the second biconic lens. The driving unit drives the diffuser to move with respect to the laser beam so that the ratio of the M² of the laser beam exiting from the second biconic lens in a first direction to the M² thereof in a second direction is greater than 2, wherein the two directions are substantially perpendicular to each other.

Claims

1. A beam generating apparatus comprising:

a laser light source, outputting a laser beam;

a speckle suppressing module, comprising;

a first biconic lens, disposed on a transmission path of the laser beam;

a diffuser, disposed on the transmission path of the laser beam from the first biconic lens; and

a second biconic lens, disposed on the transmission path of the laser beam from the diffuser;

a light homogenizing module, disposed on the transmission path of the laser beam from the second biconic lens, wherein the laser beam is transmitted to the first biconic lens, the diffuser, the second biconic lens and the light homogenizing module in sequence; and

a driving unit, driving the diffuser to move with respect to the laser beam so that a ratio of M squared of the laser beam exiting from the second biconic lens in a first direction to M squared of the laser beam exiting from the second biconic lens in a second direction is greater than 2, wherein the first direction is substantially perpendicular to the second direction.

2. The beam generating apparatus as claimed in claim 1, wherein a curved surface of the first biconic lens and a curved surface of the second biconic lens are not curved in the first direction but are curved in the second direction.

3. The beam generating apparatus as claimed in claim 2, wherein the curved surface of the first biconic lens faces the laser light source and the curved surface of the second biconic lens faces the light homogenizing module.

4. The beam generating apparatus as claimed in claim 1, wherein the laser beam is a pulse laser beam, and a ratio of pulse repetition frequency of the laser beam to a average rate of movement of a location of the diffuser irradiated by the laser beam is less than or equal to 500.

5. The beam generating apparatus as claimed in claim 4, further comprising a control unit electrically connected to the laser light source and the driving unit.

6. The beam generating apparatus as claimed in claim 1, wherein a wavelength of the laser beam ranges from 100 nm to 1000 μ

m.

7. The beam generating apparatus as claimed in claim 1, wherein the driving unit drives the diffuser to rotate.

8. The beam generating apparatus as claimed in claim 1, wherein the driving unit drives the diffuser to make reciprocative translational vibration.

9. The beam generating apparatus as claimed in claim 8, wherein the diffuser makes reciprocative translational vibration along the first direction.

10. The beam generating apparatus as claimed in claim 1, wherein the light homogenizing module comprises:

a first lenticular lens array, disposed on the transmission path of the laser beam from the second biconic lens; and

a second lenticular lens array, disposed on the transmission path of the laser beam from the first lenticular lens array.

11. The beam generating apparatus as claimed in claim 10, wherein the first lenticular lens array comprises a plurality of first lenticular lenses, each of the first lenticular lenses extends along the second direction, the first lenticular lenses are arranged along the first direction, the second lenticular lens array comprises a plurality of second lenticular lenses, each of the second lenticular lenses extends along the second direction, and the second lenticular lenses are arranged along the first direction.

12. The beam generating apparatus as claimed in claim 1, further comprising a condenser lens and a third biconic lens, wherein the condenser lens is disposed on the transmission path of the laser beam and located between the light homogenizing module and the third biconic lens.

13. The beam generating apparatus as claimed in claim 12, wherein the laser beam after passing through the light homogenizing module, the condenser lens and the third biconic lens generates a linear spot, the major axis of the linear spot is L, the minor axis of the linear spot is W, the diffuser has a plurality of micro-structures in periodical arrangement, the laser beam has a beam waist between the first biconic lens and the second biconic lens, the diffuser is located between the beam waist and the second biconic lens, the tops of the micro-structures is separated from the beam waist by a distance d, and a pitch of the micro-structures is p, wherein L/W is in direct proportion to p/d.

14. The beam generating apparatus as claimed in claim 12, wherein a curved surface of the third biconic lens faces the speckle suppressing module.

15. The beam generating apparatus as claimed in claim 12, wherein a curved surface of the third biconic lens is not curved in the first direction but curved in the second direction.

16. The beam generating apparatus as claimed in claim 1, further comprising:

a beam-expanding unit, disposed on the transmission path of the laser beam and located between the laser light source and the speckle suppressing module.

17. The beam generating apparatus as claimed in claim 1, wherein the laser light source is a continuous wave laser light source.