DEVICE FOR MATERIAL WORKING BY A LASER BEAM, AND METHOD FOR ITS PRODUCTION
First Claim
1. A device for material processing by a laser beam of the type having a flexible light guide for directing the laser beam, said device comprising:
- a single homogeneous unclad quartz rod having 1. a beam entrance face positioned to intersect the beam of light generated by a laser and having a diameter approximately equal to the diameter of the laser beam, 2. a long, flexible fiberlike portion with a diameter substantially smaller than the diameter of said beam entrance face, and a length substantially larger than its diameter, 3. a portion of continuously decreasing diameter extending from said entrance face to one end of said fiberlike portion, 4. a beam exit face of greater diameter than the diameter of said fiberlike portion, 5. a portion of continuously increasing diameter extending from the other end of said fiberlike portion to said beam exit face;
a flexible tubing for protectably enclosing said quartz rod; and
a plurality of spacers disposed within said tubing and positioned along the length of said quartz rod, each said spacers having an aperture through which said rod passes, each said spacer being coated with a material having an index of refraction less than said quartz rod, said spacers preventing contact of said rod with said tubing when said tubing is bent.
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Abstract
A device for material working by a laser beam wherein an unclad, optically and materially homogeneous quartz rod having enlarged ends tapered to a fiberlike center portion is protectively enclosed in a flexible tube. Preferably, the tube is provided with annular spacer rings of quartz glass to keep the fiber from contacting the tube wall. To provide high power and high efficiency transmission, the tube is filled with a circulating liquid having a refractive index less than that of the fiber, and the spacers are coated with substance having a refractive index which is the same as that of the liquid. The fiber is made by heating a rotating quartz rod and drawing it. The rotation is controllably slowed and stopped to prevent twisting as the rod softens. Alternatively, a quartz rod is etched to the desired form.
115 Citations
28 Claims
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1. A device for material processing by a laser beam of the type having a flexible light guide for directing the laser beam, said device comprising:
- a single homogeneous unclad quartz rod having 1. a beam entrance face positioned to intersect the beam of light generated by a laser and having a diameter approximately equal to the diameter of the laser beam, 2. a long, flexible fiberlike portion with a diameter substantially smaller than the diameter of said beam entrance face, and a length substantially larger than its diameter, 3. a portion of continuously decreasing diameter extending from said entrance face to one end of said fiberlike portion, 4. a beam exit face of greater diameter than the diameter of said fiberlike portion, 5. a portion of continuously increasing diameter extending from the other end of said fiberlike portion to said beam exit face;
a flexible tubing for protectably enclosing said quartz rod; and
a plurality of spacers disposed within said tubing and positioned along the length of said quartz rod, each said spacers having an aperture through which said rod passes, each said spacer being coated with a material having an index of refraction less than said quartz rod, said spacers preventing contact of said rod with said tubing when said tubing is bent.
- a single homogeneous unclad quartz rod having 1. a beam entrance face positioned to intersect the beam of light generated by a laser and having a diameter approximately equal to the diameter of the laser beam, 2. a long, flexible fiberlike portion with a diameter substantially smaller than the diameter of said beam entrance face, and a length substantially larger than its diameter, 3. a portion of continuously decreasing diameter extending from said entrance face to one end of said fiberlike portion, 4. a beam exit face of greater diameter than the diameter of said fiberlike portion, 5. a portion of continuously increasing diameter extending from the other end of said fiberlike portion to said beam exit face;
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2. The device of claim 1 additionally including:
- a fluid flowing through said tubing, said fluid having an index of refraction lower than the index of refraction of said rod, said fluid serving to cool the entire quartz rod and also to clad the rod so as to cause efficient transfer of light energy from said entrance face to said exit face.
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3. a portion of continuously decreasing diameter extending from said entrance face to one end of said fiberlike portion,
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4. The device of claim 1 wherein the diameter of the light entrance face is between 3 and 10 mm.
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5. The device of claim 1 wherein the length of said decreasing diameter portion is at least 50 times the diameter of said beam entrance face.
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6. The device of claim 5 wherein the length of said decreasing diameter part is less than 100 times the diameter of said beam entrance face.
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7. The device of claim 1 wherein the length of said part with increasing diameter is smaller than the length of said part with decreasing diameter, the preferred length being about 100 mm.
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8. The device of claim 1 wherein said light exit face has the form of a lens.
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9. The device of claim 1 further comprising a detachable focusing optic located at said light exit end of said light guide rod.
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10. The device of claim 1 wherein one end of said flexible tubing is formed as a gas outlet nozzle, and the other end thereof is provided with a device for the introduction of a gas, and said flexible tubing forming a gas transmitting channel.
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11. The device of claim 1 further comprising a visible light source and means to couple the beam from said visible light source into the path of the laser beam.
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12. The device of claim 1 wherein the laser beam is generated by a laser including a front and a rear mirror, the space between said front and said rear mirror being the laser resonator, said device further including, a rotatable plate located inside the resonator of said laser and made from a laser light transparent material, and a means by which said plate can be rotated to control the poweR of the laser.
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13. The device of claim 12 further comprising means located at the light exit end of said flexible tube for actuating said plate rotating means.
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14. The device of claim 1 wherein said laser is mounted in a vertical position and said flexible tube is mounted on the lower end of the laser.
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15. The device of claim 1 further comprising:
- a liquid having an index of refraction less than that of said rod said liquid being contained within said tubing and surrounding said rod.
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16. The device of claim 1 wherein the coating on said spacers has substantially the same index of refraction as that of said liquid.
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17. The device of claim 16 wherein said spacers are coated with a vacuum deposit of a substance taken from the group consisting of calcium fluoride or magnesium fluoride.
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18. The device of claim 1 further comprising means for recirculating said liquid through said tubing.
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19. The device of claim 1 additionally including:
- a fluid inside said tubing, said fluid having an index of refraction lower than the index of refraction of said rod, said fluid serving to cool the entire quartz rod and also to clad the rod so as to cause efficient transfer of light energy from said entrance face to said exit face.
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20. In a device for material processing by a laser beam, which device includes a laser and a flexible light guide, the improvement wherein said light guide comprises:
- a homogeneous uncoated and unclad quartz rod having a. a beam entrance face having a diameter in the order of the diameter of the laser beam, b. a long, fine flexible fiberlike part of a diameter substantially less than said diameter of the entrance face, c. a beam exit face of diameter greater than that of said fiberlike part, d. a portion of a continuously decreasing diameter extending from said entrance face to said fiberlike part, e. a portion of increasing diameter extending from said fiberlike part to said exit face, the length of this portion being smaller than said portion with decreasing diameter, f. a flexible tubing protectively enclosing said quartz rod, g. a liquid having an index of refraction less than that of said quartz rod being contained within said tubing and surrounding said rod; and
h. a series of at least two ringlike spacers made from dielectric material, having an outer diameter apporximately equal to the inner diameter of said tubing, positioned inside said flexible tubing to maintain said light guide out of contact with the wall of said tubing, maintaining at least the portion with decreasing and increasing diameter out of contact with the wall of said tubing.
- a homogeneous uncoated and unclad quartz rod having a. a beam entrance face having a diameter in the order of the diameter of the laser beam, b. a long, fine flexible fiberlike part of a diameter substantially less than said diameter of the entrance face, c. a beam exit face of diameter greater than that of said fiberlike part, d. a portion of a continuously decreasing diameter extending from said entrance face to said fiberlike part, e. a portion of increasing diameter extending from said fiberlike part to said exit face, the length of this portion being smaller than said portion with decreasing diameter, f. a flexible tubing protectively enclosing said quartz rod, g. a liquid having an index of refraction less than that of said quartz rod being contained within said tubing and surrounding said rod; and
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21. The device of claim 20 wherein the diameter of said fiberlike part is between 0.01 and 0.4 mm and the length of said fiberlike part is at least 400 mm.
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22. The device of claim 20 wherein the diameter of the entrance and exit face is between 0.3 and 10 mm.
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23. The device of claim 20 wherein the length of said decreasing diameter portion is at least 50 times the diameter of said beam entrance face.
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24. The device of claim 20 wherein the length of said part with increasing diameter is smaller than the length of said part with decreasing diameter, the preferred length being about 100 mm.
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25. The device of claim 20 wherein said light exit face has a spherical curvature.
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26. The device of claim 20 wherein the rod contacting surfaces of said dielectric spacers are of the same index of refraction as that of said liquid.
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27. The device of claim 26 wherein said ringlike spacers are made from glass and are coated with a vacuum deposit of a substance taken from the group consisting of calcium fluoride or magnesium fluoride.
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28. The device of claim 20 further comprising means for recirculating said liquid through said tubing.
Specification