Method and Apparatus Providing Increased UVLED Intensity and Uniform Curing of Optical-Fiber Coatings

• US 20120040105A1
• Filed: 08/10/2011
• Published: 02/16/2012
• Est. Priority Date: 08/10/2010
• Status: Abandoned Application

• Current Assignee: Draka-Comteq USA Incorporated (Draka-Comteq)
• Original Assignee: Draka-Comteq USA Incorporated (Draka-Comteq)
• Inventors: Overton, Bob J.
• Application Number:
  US13/206,601
• Publication Number:
  US 20120040105A1
• Time in Patent Office: Days
• US Class Current: 427/558
• CPC Class Codes: B05D 2203/35 Glass
• CPC Class Codes: B05D 2256/00 Wires or fibres
• CPC Class Codes: B05D 3/067 Curing or cross-linking the coating
• CPC Class Codes: C03C 25/12 General methods of coating; Devices therefor
• CPC Class Codes: C03C 25/6226 Ultraviolet

Abstract

A UVLED apparatus and a related method provide increased UVLED intensity to promote efficient curing of a coated glass fiber. The apparatus employs a plurality of UVLED sources, each UVLED source emitting an oscillating output of ultraviolet radiation. Typically, at least two of the UVLED sources have oscillating outputs of ultraviolet radiation that are out of phase with one another. During curing, an incompletely cured coating on a glass fiber absorbs electromagnetic radiation emitted from the UVLED sources.

Claims

1. A method of curing a coating on a glass fiber, comprising:

passing a glass fiber having an incompletely cured coating at a line speed v_f through a cavity and along a curing axis that is defined by the cavity;

emitting UV radiation from a first UVLED array into the cavity to promote the curing of the coating, the first UVLED array comprising a plurality of UVLED sources each of which emit an oscillating output x_n(t) of UV radiation having a maximum output intensity x_n(t)_max and a minimum output intensity x_n(t)_min;

wherein the first UVLED array defines a normalized sum x_total(t,v_f);

2. The method according to claim 1, wherein each of the UVLED sources in the first UVLED array are driven at substantially the same current.

3. The method according to claim 1, wherein at least two of the UVLED sources in the first UVLED array are driven at different currents.

4. The method according to claim 1, wherein:

the output x_n(t) of each UVLED source in the first UVLED array defines a pulse train with a duty cycle equal to A/B;

each UVLED source in the first UVLED array has substantially the same maximum output intensity x_n(t)_max and substantially the same minimum output intensity x_n(t)_min;

the first UVLED array has B UVLED sources; and

x_total(t,v_f)≈

A(x_n(t)_max+x_n(t)_min).

5. The method according to claim 1, comprising the step of adjusting the phase of the output of at least one UVLED source in response to a change in the line speed v_f of the glass fiber so that x_total(t,v_f) has a substantially constant value for a given line speed.

6. The method according to claim 1, comprising the step of increasing the output intensity of one or more of the UVLED sources in the first UVLED array in response to an increase in the line speed v_f of the glass fiber.

7. The method according to claim 1, comprising the step of decreasing the output intensity of one or more of the UVLED sources in the first UVLED array in response to a decrease in the line speed v_f of the glass fiber.

8. A method of curing a coating on a glass fiber, comprising:

passing a glass fiber having an incompletely cured coating at a line speed v_f through a cavity and along a curing axis that is defined by the cavity;

driving a plurality of UVLED sources that define a first UVLED array, each UVLED source in the first UVLED array being driven at a current that is greater than its maximum rated current, wherein each UVLED source in the first UVLED array has an oscillating output x_n(t) of UV radiation having a maximum output intensity x_n(t)_max and a minimum output intensity x_n(t)_min, the maximum output intensity x_n(t)_max of each UVLED source in the first UVLED array being greater than could be achieved if each of the UVLED sources was driven at its maximum rated current; and

emitting UV radiation from the first UVLED array into the cavity to promote the curing of the coating.

9. The method according to claim 8, wherein the output of each UVLED source in the first UVLED array defines a pulse train.

10. The method according to claim 8, wherein:

the first UVLED array defines a normalized sum x_total(t,v_f);

11. The method according to claim 10, wherein the first UVLED source and at least one other UVLED source in the first UVLED array are separated along the curing axis.

12. The method according to claim 11, wherein:

the output x_n(t) of each UVLED source in the first UVLED array defines a pulse train with a duty cycle equal to A/B;

each UVLED source in the first UVLED array has substantially the same maximum output intensity x_n(t)_max and substantially the same minimum output intensity x_n(t)_min;

the first UVLED array has B UVLED sources; and

x_total(t,v_f)≈

A(x_n(t)_max+x_n(t)_min).

13. The method according to claim 11, comprising the step of adjusting the phase of the output of at least one UVLED source in the first UVLED array in response to a change in the line speed v_f of the glass fiber so that x_total(t,v_f) has a substantially constant value for a given line speed.

14. The method according to claim 8, comprising the step of increasing the output intensity of one or more of the UVLED sources in the first UVLED array in response to an increase in the line speed v_f of the glass fiber.

15. The method according to claim 8, comprising the step of decreasing the output intensity of one or more of the UVLED sources in the first UVLED array in response to a decrease in the line speed v_f of the glass fiber.

16. The method according to claim 8, comprising:

driving a plurality of UVLED sources that define a second UVLED array, each UVLED source in the second UVLED array being driven at a current that is greater than its maximum rated current, wherein each UVLED source in the second UVLED array has an oscillating output y_n(t) of UV radiation having a maximum output intensity y_n(t)_max and a minimum output intensity y_n(t)_min, the maximum output intensity y_n(t)_max of each UVLED source in the second UVLED array being greater than could be achieved if each of the UVLED sources was driven at its maximum rated current, and wherein the maximum output intensity y_n(t)_max of at least one UVLED source in the second UVLED array is different from the maximum output intensity x_n(t)_max of at least one UVLED source in the first UVLED array; and

directing UV radiation from the second UVLED array to promote the curing of the coating.

17. The method according to claim 8, wherein the maximum output intensity x_n(t)_max of each UVLED source in the first UVLED array is substantially the same.

18. The method according to claim 8, wherein, for at least two of the UVLED sources in the first UVLED array, the maximum output intensities x_n(t)_max are different.

19. An apparatus for curing a coated glass fiber, comprising:

a cavity defining a curing axis; and

a first UVLED array positioned within said cavity, said first UVLED array comprising a plurality of UVLED sources;

wherein each UVLED source in said first UVLED array is configured to have an oscillating output x_n(t) of UV radiation having a maximum output intensity x_n(t)_max and a minimum output intensity x_n(t)_min;

wherein at least two of said UVLED sources in said first UVLED array are configured to have oscillating outputs of UV radiation that are out of phase with one another;

wherein at least two of said UVLED sources in said first UVLED array are separated along the curing axis; and

wherein said first UVLED array is configured to define a normalized sum x_total(t,v_f);

20. The apparatus according to claim 19, comprising a controller electrically connected to said first UVLED array, wherein said controller is capable of adjusting the output intensity and/or phase of the oscillating outputs of said UVLED sources in said first UVLED array.

21. The apparatus according to claim 19, wherein each said UVLED source in said first UVLED array is configured to have substantially the same maximum output intensity x_n(t)_max.

22. The apparatus according to claim 19, wherein at least two of said UVLED sources in said first UVLED array are configured to have different maximum output intensities x_n(t)_max.

23. The apparatus according to claim 19, wherein:

the output x_n(t) of each said UVLED source in said first UVLED array defines a pulse train with a duty cycle equal to A/B;

each UVLED source in said first UVLED array is configured to have substantially the same maximum output intensity x_n(t)_max and substantially the same minimum output intensity x_n(t)_min;

said first UVLED array has B UVLED sources, whereby B=k; and

x_total(t,v_f)≈

A(x_n(t)_max+x_n(t)_min).

24. An apparatus for curing a coated glass fiber, comprising:

a cavity defining a curing axis; and

a first UVLED array positioned within said cavity, said first UVLED array comprising a plurality of UVLED sources;

wherein each UVLED source in said first UVLED array is configured to have an oscillating output x_n(t) of UV radiation having a maximum output intensity x_n(t)_max and a minimum output intensity x_n(t)_min, each UVLED source in said first UVLED array being configured to have a maximum output intensity x_n(t)_max that is greater than can be achieved by driving each UVLED source at its maximum rated current; and

wherein at least two of said UVLED sources in said first UVLED array are configured to have oscillating outputs of UV radiation that are out of phase with one another.

25. The apparatus according to claim 24, comprising a controller electrically connected to said first UVLED array, wherein said controller is capable of adjusting the output intensity and/or phase of the oscillating outputs of said UVLED sources in said first UVLED array.

26. The apparatus according to claim 25, wherein said controller is configured to adjust the oscillating outputs of said UVLED sources in said first UVLED array so that said first UVLED array defines a normalized sum x_total(t,v_f):

27. The apparatus according to claim 24, wherein each said UVLED source in said first UVLED array is configured to have substantially the same maximum output intensity x_n(t)_max.

28. The apparatus according to claim 24, wherein at least two of said UVLED sources in said first UVLED array are configured to have different maximum output intensities x_n(t)_max.

29. The apparatus according to claim 24, wherein:

at least two of said UVLED sources in said first UVLED array are separated along the curing axis; and

said first UVLED array is configured to defines a normalized sum x_total(t,v_f);

30. The apparatus according to claim 29, wherein:

the output x_n(t) of each said UVLED source in said first UVLED array defines a pulse train with a duty cycle equal to A/B;

each UVLED source in said first UVLED array is configured to have substantially the same maximum output intensity x_n(t)_max and substantially the same minimum output intensity x_n(t)_min;

said first UVLED array has B UVLED sources, whereby B=k; and

x_total(t,v_f)≈

A(x_n(t)_max+x_n(t)_min).

31. The apparatus according to claim 24, comprising:

a second UVLED array positioned within said cavity, said second UVLED array comprising a plurality of UVLED sources;

wherein each UVLED source in said second UVLED array is configured to have an oscillating output y_n(t) of UV radiation having a maximum output intensity y_n(t)_max and a minimum output intensity y_n(t)_min, each UVLED source in said second UVLED array being configured to have a maximum output intensity y_n(t)_max that is greater than can be achieved by driving each UVLED source at its maximum rated current; and

wherein the maximum output intensity y_n(t)_max of at least one of said UVLED sources in said second UVLED array is different from the maximum output intensity x_n(t)_max of at least one of said UVLED sources in said first UVLED array.