Chemical vapor deposition coating of fibers using microwave application

• US 6,152,072 A
• Filed: 05/26/1999
• Issued: 11/28/2000
• Est. Priority Date: 05/26/1998
• Status: Expired due to Term

• Current Assignee: California Institute of Technology
• Original Assignee: California Institute of Technology
• Inventors: Jackson, Henry W., Barmatz, Martin B., Hoover, Gordon
• Primary Examiner(s): Mills, Gregory
• Assistant Examiner(s): Hassanzadeh, Parviz
• Application Number:
  US09/320,189
• Time in Patent Office: 552 Days
• Field of Search: 118/723 MW, 118/715, 118/724, 118/722, 219/690, 219/691, 219/692, 219/693, 219/764, 219/695, 219/696, 219/697, 156/345
• US Class Current: 118/723.0MW
• CPC Class Codes: C04B 2235/5248 Carbon, e.g. graphite
• CPC Class Codes: C04B 2235/667 Sintering using wave energy, e.g. microwave sintering
• CPC Class Codes: C04B 35/62863 Silicon carbide
• CPC Class Codes: C04B 35/62884 by gas phase techniques
• CPC Class Codes: C23C 16/481 by radiant heating of the substrate
• CPC Class Codes: C23C 16/52 Controlling or regulating the coating process C23C16/45557, C23C16/279 take precedence
• CPC Class Codes: C23C 16/545 for coating elongated substrates
• CPC Class Codes: H05B 6/701 using microwave applicators
• CPC Class Codes: H05B 6/705 using microwave tuning
• CPC Class Codes: H05B 6/806 for laboratory use

Abstract

Chemical vapor deposition coating is carried out in a cylindrical cavity. The fibers are heated by a microwave source that is uses a TM0N0 mode, where O is an integer, and produces a field that depends substantially only on radius. The fibers are observed to determine their heating, and their position can be adjusted. Once the fibers are uniformly heated, a CVD reagent is added to process the fibers.

Claims

1. A fiber chemical vapor deposition apparatus comprising:

a cavity;

a microwave source producing a microwave energy in said cavity, said microwave energy forming a transverse magnetic resonant mode within said cavity; and

a plurality of fiber holding areas, within said cavity, each adapted for holding a fiber, each of said fiber holding areas having an adjustment, which allows a position of said fiber to be changed to allow said fibers to be heated substantially uniformly by said microwave energy; and

an element, in said cavity, which provides reagent for chemical vapor deposition to said fibers in a presence of heating of said fibers from said microwave.

2. An apparatus as in claim 1 wherein said cavity is cylindrical.

3. An apparatus as in claim 2 wherein said adjustment comprises a slot within the cylindrical cavity which adjusts resonance to optimize microwave energy transmission to the fiber.

4. An apparatus as in claim 2 wherein said transverse magnetic mode is one in which energy of the radiation is substantially dependent only on radius, wherein said adjustment comprises a slot which enables adjusting a radius at which a fiber is located.

5. An apparatus as in claim 2 wherein said microwave source includes an antenna, and said antenna is tunable to match to said cavity.

6. An apparatus as in claim 1 further comprising a viewing element which enables viewing the fibers.

7. An apparatus as in claim 6 wherein said viewing element comprises a window and a lens which enables viewing the position of the fibers.

8. An apparatus as in claim 6 wherein said viewing element comprises a video camera and a display monitor.

9. An apparatus as in claim 1 wherein said microwave source includes an antenna, and wherein said antenna is tunable.

10. An fiber chemical vapor deposition apparatus, comprising:

a cylindrical cavity;

a microwave source, having an antenna which has an adjustable feature to enable matching to said cavity to produce resonant radiation within said cavity;

a plurality of tubes, located in said cavity, each said tube adapted for holding a fiber to be coated, each of said tubes having an adjustment, which allows a position of said fiber to be changed to allow said fibers to be heated substantially uniformly by said radiation; and

a reagent producing device, producing reagent into said tubes, said reagent of a type which causes a chemical vapor deposition in the presence of heating.

11. An apparatus as in claim 10 wherein said microwave source produces a transverse magnetic field which is dependent substantially only on radius within the cylindrical cavity.

12. An apparatus as in claim 10 further comprising a viewing element allowing observing the tubes.

13. An apparatus as in claim 10 further comprising a microwave tuning device which tunes an amount of microwave applied to said tubes.