CA1048613A - Rf power transmission line for induction heated vapor source - Google Patents
Rf power transmission line for induction heated vapor sourceInfo
- Publication number
- CA1048613A CA1048613A CA75240290A CA240290A CA1048613A CA 1048613 A CA1048613 A CA 1048613A CA 75240290 A CA75240290 A CA 75240290A CA 240290 A CA240290 A CA 240290A CA 1048613 A CA1048613 A CA 1048613A
- Authority
- CA
- Canada
- Prior art keywords
- conductors
- flexible
- lines
- source
- supply
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
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- General Induction Heating (AREA)
Abstract
ABSTRACT OF THE DISCLOSURE
Transmission line for RF power utilizing generally flat supply and return lines each comprising a plurality of flexible, insulated conduc-tors connected together at their ends. The two lines are enclosed in a flexible sheath which holds the lines in close proximity to each other, and fields produced by the lines tend to cancel each other. The transmission line is particularly suitable for use in delivering power from a radio frequency power supply to the work coil of an induction heated vapour source.
Transmission line for RF power utilizing generally flat supply and return lines each comprising a plurality of flexible, insulated conduc-tors connected together at their ends. The two lines are enclosed in a flexible sheath which holds the lines in close proximity to each other, and fields produced by the lines tend to cancel each other. The transmission line is particularly suitable for use in delivering power from a radio frequency power supply to the work coil of an induction heated vapour source.
Description
This invention pertains generally to electrical transmission lines and more particularly to a transmission line for carrying radio frequency power from an RF power supply to the work coil of an induction heated vapor source.
Induction heated vapor sources utilized in thin -film deposition have a work coil which is energized with RF
energy to produce a magnetic field which induces current - -in the load or susceptor and subse~uently heats and vaporizes ~-the metal to be deposited. With induction heated vapor sources of the prior art, the RF current required to vaporize materials commonly used in vapor deposition is typically on the order of several hundred amperes. A current of this - magnitude requires a relatively large effective conductor, and because of the poor use factor and losses due-to the so-called skin effect, i.e. the tendency of high frequency currents to be concentrated toward the outer surface of a ; conductor, hollow water cooled conductors are generally employed for supplying the RF current to vapor source work coils. The hollow conductors are commonly fabricated -~
of copper, and they are expensive and difficult to use.
The invention provides a power transmission line for induction heated vapor sources utilizing generally - flat supply and return lines each comprising a plurality-of flexible, insulated conductors connected together at their ends. The two lines are enclosed in a flexible ~ sheath which holds the lines in a closely spaced superposed position in which the fields produced by the lines tend to cancel each other.
Objects of the invention are to provide a new and improved transmission line for RF power, to provide a
Induction heated vapor sources utilized in thin -film deposition have a work coil which is energized with RF
energy to produce a magnetic field which induces current - -in the load or susceptor and subse~uently heats and vaporizes ~-the metal to be deposited. With induction heated vapor sources of the prior art, the RF current required to vaporize materials commonly used in vapor deposition is typically on the order of several hundred amperes. A current of this - magnitude requires a relatively large effective conductor, and because of the poor use factor and losses due-to the so-called skin effect, i.e. the tendency of high frequency currents to be concentrated toward the outer surface of a ; conductor, hollow water cooled conductors are generally employed for supplying the RF current to vapor source work coils. The hollow conductors are commonly fabricated -~
of copper, and they are expensive and difficult to use.
The invention provides a power transmission line for induction heated vapor sources utilizing generally - flat supply and return lines each comprising a plurality-of flexible, insulated conductors connected together at their ends. The two lines are enclosed in a flexible ~ sheath which holds the lines in a closely spaced superposed position in which the fields produced by the lines tend to cancel each other.
Objects of the invention are to provide a new and improved transmission line for RF power, to provide a
-2-, 1~4~613 transmission line which is particularly suitable for use in carrying RF
power to the work coil of an induction heated vapor source, ~o provide a transmission line having supply and return lines each formed of a plurality of insulated conductors disposed side-by-side and connected together at their ends, and to provide a transmission line in which the supply and return lines are disposed in proximity to effect field cancellation.
Thus, in accordance with the invention, there is provided, in a transmission line for delivering power from a source to a load: A. a first group of longitudinal extending flexible wire conductors disposed side-by-side and connected electrically together at their ends to form a generallyflat supply line for connection between the source and load, said conductors being encased as a unitary structure in a flexible electrically conductive -material in which the conductors are insulated from each other; B. a second group of longitudinally extending flexible wire conductors disposed side-by-side and connected electrically together at their ends to form a generally flat return line for connection between the source and load, said conductors ~ .
being encased as a unitary structure in a flexible electrically conductivc material in which the conductors are insulated from each other; and C. flexible sheath means encasing the supply and return lines holding said lines in close proximity to each other, said sheath means permitting longitudinal movement of the lines relative to each other and to the sheath means.
Brief Description of the Drawings Fig. 1 is a top plan view of a transmission line according to the invention.
Fig. 2 is an elevational view of the transmission line of Fig. 1. -Fig. 3 is an enlarged cross-sectional view taken along line 3~3 in Fig. 20 Fig. 4 is a block diagram, illustrating the use of the transmission `, ' , , ................... ;.
.. - .- ' , .
1~486~3 line of Fig. 1 in connection with an RF power supply and an induction heated vapor source.
The transmission line includes a generally flat supply line 10, a generally flat return line 11, and an elongated sheath 12 which holds the supply and return lines together.
Supply line 10 comprises a plurality of longitudinally extending electrical conductors 16, each of which is provided with an insulative jacket 17. The insulated conductors are disposed side-by-side, and in the preferred embodiment, the insulative jackets of adjacent conductors are fused or otherwise bonded together to form a unitary structure, with the conductors remaining insulated from each other.
-3a-16~148613 Return line 11 is similar to supply line 10 and includes a plurality of longitudinally extending conductors 18 having insulative jackets 19. Conductors 18 are also disposed side-by-siae, and jackets 19 are preferably fused or otherwise bonded together to form a unitary structure.
At the ends of the supply and return lines, the conductors of each line are connected electrically together, and each line functions as a single conductor. In the embodiment illustrated, the ends of supply line conductors 16 are soldered to connectors 21, 22, and the ends of return line conductors 18 are soldered to connectors 23, -24. These connectors are fabricated of an electrically conductive material such as copper or brass. -~
The number and size of the conductors used in the supply and return lines is largely dependent upon the eurrent which the line is to carry. In a preferred transmission line for a 50 KHz current on the order of 80 amperes RMS, for example, the supply and return lines each have 30 number 20 stranded copper wire conductors. In the preferred embodiment, insulative jackets 17 and 19 are fabricated of polyvinyl chloride which can be used at temperatures up to about 100C. If the line is to be subjected to higher temperatures, in~ulative materials with higher working temperatures, such as irradiated polyvinyl chloride and kapton, can be used.
In the embodiment illustrated, sheath 12 comprises two sheets 26, 27 of a flexible insulating material, such as vinly plastic, bonded together along their outer edges to form a chamber 28 which is adapted to receive the supply and the return lines and hold them in close ; . ~ . ................................ ~ ~ . .
, ~
.
1~)48613 proximity in a superposed position, as illustrated in FIG. 3. The sheath extends substantially the entire length of the supply and return lines, although portions of the lines, designated 10a, 10b, lla, and llb, extend beyond the ends of the sheath to form leads for connecting the transmission line to the terminals of a power source and load. If desired, the sheath can be formed of a heat shrinkable material.
Operation and use of the transmission line can be described briefly with reference to FIG. 4 wherein the line is shown connected between an RF power supply 31 and a vapor source 32 of the induction he&ted type. RF current from power supply 31 flows through conductors 10 and 11 to the work coil in the vapor source ~, and the magnetic and electric fields produced by the current in the two lines -tend to cancel each other.
The transmission line has a number of important features and advantages. It is flexible, light in weight, and easy to use. Moreover, it is economical and easy to manufacture. The multiconductor supply and return lines have two to three times the current carrying capacity of flat strip conductors of comparable cross-sectional area, and the positioning of the two lines in close proximity provides effective cancellation of the electric and -magnetic fields produced by the RF current in the lines. --- Unlike flat strip conductors where the current tends to be concentrated in the outer edges of the conductor, in the multiconductor transmission line of the invention the current tends to be distributed evenly among the conductors across the line. Field cancellation occurs 1~148613 between pairs of individual conductors in the supply and return lines, and this cancellation helps to keep the current toward the centers of the individual conductors.
In addition, the multiconductor line is more flexible and easier to use than a line having flat strip conductors.
It is apparent from the foregoing that a new and improved transmission line has been provided. While only the presently preferred embodiment has been described as will be apparent to those familiar with the art, certain changes and modifications can be made without departing from the scope of the invention as defined by the following claims.
power to the work coil of an induction heated vapor source, ~o provide a transmission line having supply and return lines each formed of a plurality of insulated conductors disposed side-by-side and connected together at their ends, and to provide a transmission line in which the supply and return lines are disposed in proximity to effect field cancellation.
Thus, in accordance with the invention, there is provided, in a transmission line for delivering power from a source to a load: A. a first group of longitudinal extending flexible wire conductors disposed side-by-side and connected electrically together at their ends to form a generallyflat supply line for connection between the source and load, said conductors being encased as a unitary structure in a flexible electrically conductive -material in which the conductors are insulated from each other; B. a second group of longitudinally extending flexible wire conductors disposed side-by-side and connected electrically together at their ends to form a generally flat return line for connection between the source and load, said conductors ~ .
being encased as a unitary structure in a flexible electrically conductivc material in which the conductors are insulated from each other; and C. flexible sheath means encasing the supply and return lines holding said lines in close proximity to each other, said sheath means permitting longitudinal movement of the lines relative to each other and to the sheath means.
Brief Description of the Drawings Fig. 1 is a top plan view of a transmission line according to the invention.
Fig. 2 is an elevational view of the transmission line of Fig. 1. -Fig. 3 is an enlarged cross-sectional view taken along line 3~3 in Fig. 20 Fig. 4 is a block diagram, illustrating the use of the transmission `, ' , , ................... ;.
.. - .- ' , .
1~486~3 line of Fig. 1 in connection with an RF power supply and an induction heated vapor source.
The transmission line includes a generally flat supply line 10, a generally flat return line 11, and an elongated sheath 12 which holds the supply and return lines together.
Supply line 10 comprises a plurality of longitudinally extending electrical conductors 16, each of which is provided with an insulative jacket 17. The insulated conductors are disposed side-by-side, and in the preferred embodiment, the insulative jackets of adjacent conductors are fused or otherwise bonded together to form a unitary structure, with the conductors remaining insulated from each other.
-3a-16~148613 Return line 11 is similar to supply line 10 and includes a plurality of longitudinally extending conductors 18 having insulative jackets 19. Conductors 18 are also disposed side-by-siae, and jackets 19 are preferably fused or otherwise bonded together to form a unitary structure.
At the ends of the supply and return lines, the conductors of each line are connected electrically together, and each line functions as a single conductor. In the embodiment illustrated, the ends of supply line conductors 16 are soldered to connectors 21, 22, and the ends of return line conductors 18 are soldered to connectors 23, -24. These connectors are fabricated of an electrically conductive material such as copper or brass. -~
The number and size of the conductors used in the supply and return lines is largely dependent upon the eurrent which the line is to carry. In a preferred transmission line for a 50 KHz current on the order of 80 amperes RMS, for example, the supply and return lines each have 30 number 20 stranded copper wire conductors. In the preferred embodiment, insulative jackets 17 and 19 are fabricated of polyvinyl chloride which can be used at temperatures up to about 100C. If the line is to be subjected to higher temperatures, in~ulative materials with higher working temperatures, such as irradiated polyvinyl chloride and kapton, can be used.
In the embodiment illustrated, sheath 12 comprises two sheets 26, 27 of a flexible insulating material, such as vinly plastic, bonded together along their outer edges to form a chamber 28 which is adapted to receive the supply and the return lines and hold them in close ; . ~ . ................................ ~ ~ . .
, ~
.
1~)48613 proximity in a superposed position, as illustrated in FIG. 3. The sheath extends substantially the entire length of the supply and return lines, although portions of the lines, designated 10a, 10b, lla, and llb, extend beyond the ends of the sheath to form leads for connecting the transmission line to the terminals of a power source and load. If desired, the sheath can be formed of a heat shrinkable material.
Operation and use of the transmission line can be described briefly with reference to FIG. 4 wherein the line is shown connected between an RF power supply 31 and a vapor source 32 of the induction he&ted type. RF current from power supply 31 flows through conductors 10 and 11 to the work coil in the vapor source ~, and the magnetic and electric fields produced by the current in the two lines -tend to cancel each other.
The transmission line has a number of important features and advantages. It is flexible, light in weight, and easy to use. Moreover, it is economical and easy to manufacture. The multiconductor supply and return lines have two to three times the current carrying capacity of flat strip conductors of comparable cross-sectional area, and the positioning of the two lines in close proximity provides effective cancellation of the electric and -magnetic fields produced by the RF current in the lines. --- Unlike flat strip conductors where the current tends to be concentrated in the outer edges of the conductor, in the multiconductor transmission line of the invention the current tends to be distributed evenly among the conductors across the line. Field cancellation occurs 1~148613 between pairs of individual conductors in the supply and return lines, and this cancellation helps to keep the current toward the centers of the individual conductors.
In addition, the multiconductor line is more flexible and easier to use than a line having flat strip conductors.
It is apparent from the foregoing that a new and improved transmission line has been provided. While only the presently preferred embodiment has been described as will be apparent to those familiar with the art, certain changes and modifications can be made without departing from the scope of the invention as defined by the following claims.
Claims (3)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. In a transmission line for delivering power from a radio frequency power supply to the work coil of an induction heated vapor source:
A. a radio frequency power source;
B. an induction heated vapor source having a work coil adapted to be energized with RF energy to produce a magnetic field for inducing a current in a material to be vaporized or in an electrically conductive susceptor in contact with the material to be vaporized;
C. a supply line comprising a plurality of flexible electrically conductive wires disposed side-by-side extending between the power supply and vapor source and and flexible electrically insulative material encasing the wires to form a generally flat unitary struture in which the wires are insulated from each other;
D. means connecting the ends of the supply line wires electrically together at the power supply and vapor source, respectively;
E. a return line comprising a plurality of flexible electrically conductive wires disposed side-by-side extending between the power supply and vapor source and flexible electrically insulative material encasing the wires to form a generally flat unitary structure in which the wires are insulated from each other;
F. means connecting the ends of the return line wires electrically together at the power supply and vapor source, respectively; and G. an insulative flexible sheath extending substantially the length of the supply and return lines serving to hold the lines together in a closely spaced superposed position and permit at least limited longitudinal movement of the lines relative to each other and to the sheath.
A. a radio frequency power source;
B. an induction heated vapor source having a work coil adapted to be energized with RF energy to produce a magnetic field for inducing a current in a material to be vaporized or in an electrically conductive susceptor in contact with the material to be vaporized;
C. a supply line comprising a plurality of flexible electrically conductive wires disposed side-by-side extending between the power supply and vapor source and and flexible electrically insulative material encasing the wires to form a generally flat unitary struture in which the wires are insulated from each other;
D. means connecting the ends of the supply line wires electrically together at the power supply and vapor source, respectively;
E. a return line comprising a plurality of flexible electrically conductive wires disposed side-by-side extending between the power supply and vapor source and flexible electrically insulative material encasing the wires to form a generally flat unitary structure in which the wires are insulated from each other;
F. means connecting the ends of the return line wires electrically together at the power supply and vapor source, respectively; and G. an insulative flexible sheath extending substantially the length of the supply and return lines serving to hold the lines together in a closely spaced superposed position and permit at least limited longitudinal movement of the lines relative to each other and to the sheath.
2. In a transmission line for delivering power from a source to a load:
A. a first group of longitudinally extending flexible wire.conductors disposed side-by-side and connected electrically together at their ends to form a generally flat supply line for connection between the source and load, said conductors having individual insulative jackets encasing the same, said jackets being bonded together along their lateral edges to form a unitary structure;
B. a second group of longitudinally extend-ing flexible wire conductors disposed side-by-side and connected electrically together at their ends to form a generally flat return line for connection between the source and load, said conductors having individual insulative jackets encasing the same, said jackets being bonded together along their lateral edges to form a unitary structure; and C. flexible sheath means encasing the supply and return lines and holding said lines in close proximity to each other, said sheath means permitting longitudinal movement of the lines relative to each other and to the sheath means.
A. a first group of longitudinally extending flexible wire.conductors disposed side-by-side and connected electrically together at their ends to form a generally flat supply line for connection between the source and load, said conductors having individual insulative jackets encasing the same, said jackets being bonded together along their lateral edges to form a unitary structure;
B. a second group of longitudinally extend-ing flexible wire conductors disposed side-by-side and connected electrically together at their ends to form a generally flat return line for connection between the source and load, said conductors having individual insulative jackets encasing the same, said jackets being bonded together along their lateral edges to form a unitary structure; and C. flexible sheath means encasing the supply and return lines and holding said lines in close proximity to each other, said sheath means permitting longitudinal movement of the lines relative to each other and to the sheath means.
3. In a transmission line for delivering power from a source to a load:
A. a first group of longitudinal extending flexible wire conductors disposed side-by-side and connected electrically together at their ends to form a generally flat supply line for connection between the source and load, said conductors being encased as a unitary structure in a flexible electrical-ly insulative material in which the conductors are insulated from each other;
B. a second group of longitudinally extending flexible wire conductors disposed side-by-side and connected electrically together at their ends to form a generally flat return line for connection between the source and load, said conductors being encased as a unitary structure in a flexible electrically conductive material in which the conductors are insulated from each other; and C. flexible sheath means encasing the supply and return lines holding said lines in close proximity to each other, said sheath means permitting longitudinal movement of the lines relative to each other and to the sheath means.
A. a first group of longitudinal extending flexible wire conductors disposed side-by-side and connected electrically together at their ends to form a generally flat supply line for connection between the source and load, said conductors being encased as a unitary structure in a flexible electrical-ly insulative material in which the conductors are insulated from each other;
B. a second group of longitudinally extending flexible wire conductors disposed side-by-side and connected electrically together at their ends to form a generally flat return line for connection between the source and load, said conductors being encased as a unitary structure in a flexible electrically conductive material in which the conductors are insulated from each other; and C. flexible sheath means encasing the supply and return lines holding said lines in close proximity to each other, said sheath means permitting longitudinal movement of the lines relative to each other and to the sheath means.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA75240290A CA1048613A (en) | 1975-11-24 | 1975-11-24 | Rf power transmission line for induction heated vapor source |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA75240290A CA1048613A (en) | 1975-11-24 | 1975-11-24 | Rf power transmission line for induction heated vapor source |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1048613A true CA1048613A (en) | 1979-02-13 |
Family
ID=4104589
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA75240290A Expired CA1048613A (en) | 1975-11-24 | 1975-11-24 | Rf power transmission line for induction heated vapor source |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1048613A (en) |
-
1975
- 1975-11-24 CA CA75240290A patent/CA1048613A/en not_active Expired
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