Patent US4890294A successfully refreshed from Google Patents.
US4890294A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Plasma apparatus
Assignee: Mitsubishi Electric Corp
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Filing: 1988-01-25
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Granted: 1989-12-26
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Expires: 2008-01-25
Abstract
Abstract The invention relates to a plasma apparatus where plasma is generated utilizing microwave discharge and laser excitation is performed and plasma processing is performed. More specifically, in a plasma apparatus where a microwave from a microwave oscillator is transmitted through a microwave transmission path to a microwave circuit, and plasma is generated by a microwave discharge within the microwave circuit, a plasma generating medium for generating the plasma is filled in a space formed between a conductor wall constituting a part of the microwave circuit and a dielectric installed opposite to the conductor wall, and the microwave circuit forms microwave mode having an electric field component orthogonal to the boundary between the dielectric and the plasma.
Inventors
- 👤 Junichi Nishimae
- 👤 Kenji Yoshizawa
- 👤 Masakazu Taki
- 👤 Yoshihiro Ueda
- 👤 Tadashi Yanagi
- 👤 Akihiko Iwata
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 14:54
CPC Classifications
H; H01; H01J; H01J37/00; H01J37/32; H01J37/32009; H01J37/32192; H01J37/32321; H01J37/32339; H01S; H01S3/00; H01S3/02; H01S3/03; H01S3/0315; H01S3/09; H01S3/097; H01S3/0975; H05; H05H; H05H1/00; H05H1/24; H05H1/46
Claims Analysis
Total Claims: 50
Claim 1
Independent Claim
129 words
A gas laser comprising a laser resonant cavity having a plasma discharge space formed therein and including a laser optical axis extending therein, a source of microwave energy including a microwave oscillator, and a microwave transmission path connecting said source of microwave energy to said plasma discharge space for providing microwave excitation to a plasma generating medium in said plasma discharge space, said plasma discharge space comprising a conductor wall forming a part of the plasma discharge space and a dielectric positioned opposite to the conductor wall to form together with said conductor wall and within said plasma discharge space a microwave excitation mode having an electric field component orthogonal to the boundary between the dielectric and the plasma excited in said plasma discharge space by the microwave energy.
Claim 2
Dependent Claim
129 words
A gas laser comprising a laser resonant cavity having a plasma discharge space formed therein and including a laser optical axis extending therein, a source of microwave energy including a microwave oscillator, and a microwave transmission path connecting said source of microwave energy to said plasma discharge space for providing microwave excitation to a plasma generating medium in said plasma discharge space, said plasma discharge space comprising a conductor wall forming a part of the plasma discharge space and a dielectric positioned opposite to the conductor wall to form together with said conductor wall and within said plasma discharge space a microwave excitation mode having an electric field component orthogonal to the boundary between the dielectric and the plasma excited in said plasma discharge space by the microwave energy.
Claim 3
Dependent Claim
18 words
A gas laser as set forth in claim 1, wherein the plasma discharge space comprises a microwave cavity.
Claim 4
Dependent Claim
22 words
A gas laser as set forth in claim 1, wherein the plasma discharge space comprises a coaxial line or a strip line.
Claim 5
Dependent Claim
19 words
A gas laser as set forth in claim 1, wherein the plasma discharge space comprises a surface wave line.
Claim 6
Dependent Claim
39 words
A gas laser as set forth in claim 1, including a projection extending inwardly in the region of said plasma discharge space to provide a strong electromagnetic field portion by concentration of the electromagnetic field produced by the projection.
Claim 7
Dependent Claim
23 words
A gas laser as set forth in claim 1, wherein at least a part of the microwave transmission path comprises a horn waveguide.
Claim 8
Dependent Claim
19 words
A gas laser as set forth in claim 1, wherein the plasma generating medium is CO 2 laser gas.
Claim 9
Dependent Claim
18 words
A gas laser as set forth in claim 1, wherein the plasma generating medium is excimer laser gas.
Claim 10
Dependent Claim
55 words
A gas laser as set forth in claim 1, wherein a groove is formed in the conductor wall to constitute a part of the plasma discharge space, and the plasma generating medium is filled in a space formed by covering an opening portion of the groove using the dielectric as an incident window of microwave.
Claim 11
Dependent Claim
20 words
A gas laser as set forth in claim 9, wherein the dielectric and the conductor are contacted in a plane.
Claim 12
Dependent Claim
25 words
A gas laser as set forth in claim 9, wherein the plasma discharge space has a ridge and the groove is formed on the ridge.
Claim 13
Dependent Claim
18 words
A gas laser as set forth in claim 9, wherein the plasma discharge space is a rectangular cavity.
Claim 14
Dependent Claim
27 words
A gas laser as set forth in claim 1, wherein the source of microwave energy is an apparatus to excite pulse microwave in the plasma discharge space.
Claim 15
Dependent Claim
19 words
A plasma apparatus as set forth in claim 13, wherein the pulse microwave has frequency 500 Hz or more.
Claim 16
Dependent Claim
36 words
A gas laser as set forth in claim 13, wherein said pulse microwave generating means is a microvace oscillator driven by a power source to generate high voltage in ripple by a half-wave voltage multiplying circuit.
Claim 17
Dependent Claim
37 words
A gas laser as set forth in claim 13, wherein the pulse microwave is generated by the microwave oscillator being driven by a high-voltage pulse source where DC of high voltage is interrupted by a switching element.
Claim 18
Dependent Claim
28 words
A gas laser as set forth in claim 13, wherein the pulse microwave exciting means has quiescent time less than thermal time constant of the plasma generating medium.
Claim 19
Dependent Claim
86 words
A gas laser as set forth in claim 16, wherein the pulse source to suply pulse voltage to the microwave oscillator is a power source apparatus to drive a non-linear element or device where current does not flow at voltage less than the prescribed voltage E z and current flows at the prescribed voltage E z or more, and a semiconductor switching element to control power flowing from voltage source to the non-linear element or device is connected in series with the non-linear element or device.
Claim 20
Dependent Claim
23 words
A gas laser as set forth in claim 18, wherein the non-linear element or device is provided with dividing resistors connected in parallel.
Claim 21
Dependent Claim
39 words
A gas laser as set forth in claim 18 or claim 19, wherein the semiconductor switching element has a withstand voltage lower than a voltage E o of the voltage source and higher than E o -E z .
Claim 22
Dependent Claim
20 words
A gas laser as set forth in claims 18 or 19, wherein plural semiconductor switching elements are connected in series.
Claim 23
Dependent Claim
21 words
A gas laser as set forth in claims 18 or 19, wherein the semiconductor switching element is a field effect transistor.
Claim 24
Dependent Claim
20 words
A gas laser as set forth in claims 18 or 19, wherein the semiconductor switching element is a bipolar transistor.
Claim 25
Dependent Claim
18 words
A gas laser as set forth in claims 18 or 19, wherein the non-linear element is a magnetron.
Claim 26
Dependent Claim
22 words
A gas laser as set forth in claim 1, wherein the conductor wall in the space is coated by a ceramic layer.
Claim 27
Dependent Claim
25 words
A gas laser as set forth in claim 25, wherein the thickness of the ceramic layer is 1/10 of that of the dielectric or less.
Claim 28
Dependent Claim
37 words
A gas laser as set forth in claim 25, wherein the thickness of the ceramic layer divided by its dielectric constant is less than the resistivity of the plasma divided by the surge impedance of a vacuum.
Claim 29
Dependent Claim
22 words
A gas laser as set forth in claim 25, wherein the ceramic layer comprises a material which does not react with halogen.
Claim 30
Dependent Claim
39 words
A gas laser as set forth in claim 1, wherein a reservoir tank communicates with the space by a connection penetrating hole and stores the plasma generating medium to be replaced for the plasma generating medium in the space.
Claim 31
Dependent Claim
25 words
A gas laser as set forth in claim 29, wherein the connection penetrating hole is provided with a gas permeable member which reflects the microwave.
Claim 32
Dependent Claim
19 words
A gas laser as set forth in claim 29, wherein the reservoir tank is installed in said conductor wall.
Claim 33
Dependent Claim
128 words
A gas laser as set forth in claim 1, wherein a recess comprising a first conductor wall to constitute a part of the plasma discharge space as a bottom surface and a second conductor wall as a side surface is installed, an opening portion of the recess is covered by a first dielectric body being an incident window of the microwave, a second dielectric body is arranged on the second conductor wall, the plasma generating medium is filled in a space formed by the first conductor wall, the first dielectric body and the second dielectric body, and the plasma discharge space forms a microwave mode having the electric field component orthogonal to the boundary between the first dielectric body and the plasma generated in the plasma producing medium.
Claim 34
Dependent Claim
76 words
A gas laser as set forth in claim 1, the space formed between the conductor wall and the dielectric acts as a light waveguide path, laser gas is filled in the space, the microwave is entered using the dielectric as a microwave incident window, and microwave mode having the electric field component orthogonal to the boundary between the dielectric and the plasma generated is formed whereby a light waveguide path type gas laser apparatus is constituted.
Claim 35
Dependent Claim
43 words
A gas laser as set forth in claim 1, wherein a part of the space other than the dielectric is made a gas permeable member to reflect the microwave, and in the space is circulated by circulation means through the gas permeable member.
Claim 36
Dependent Claim
26 words
A gas laser as set forth in claim 34, wherein the gas permeable member comprises a conductive member with a number of small holes bored thereon.
Claim 37
Dependent Claim
20 words
A gas laser as set forth in claim 34, wherein the gas permeable member comprises a honeycomb structure of metal.
Claim 38
Dependent Claim
18 words
A gas laser as set forth in claim 34, wherein the gas permeable member is a metal mesh.
Claim 39
Dependent Claim
54 words
A gas laser as set forth in claim 1, including a contact portion where the dielectric and a part of the plasma discharge space with the conductor wall formed thereon are contacted to each other, and wherein a part or the whole of the contact portion is bonded and sealed by epoxy adhesive agent.
Claim 40
Dependent Claim
64 words
A gas laser as set forth in claim 1, including a contact portion where the dielectric and a part of the plasma discharge space with the conductor wall formed thereon are contacted to each other, and wherein a part or the whole of the contact portion is subjected to metallizing and a portion of the plasma discharge space is subjected to a metal seal.
Claim 41
Dependent Claim
48 words
A gas laser as set forth in claim 1, wherein a metallized layer is provided on a surface of the dielectric on the side opposite to the space, and the other surface of the metallized layer faces directly to a cooling water path provided in the conductor wall.
Claim 42
Dependent Claim
27 words
A gas laser as set forth in claim 1, wherein a groove forms part of the space and an opening edge of the groove is made arc-shape.
Claim 43
Dependent Claim
37 words
A gas laser as set forth in claim 1, wherein a groove forms part of the space and a metallized layer covering an opening edge portion of the groove is provided on a part of the dielectric.
Claim 44
Dependent Claim
20 words
A gas laser as set forth in claim 42, wherein the metallized layer is an aluminium layer produced by evaporation.
Claim 45
Dependent Claim
37 words
A gas laser as set forth in claim 1, wherein said plasma apparatus provides a laser optical axis and the microwave transmission path and the plasma discharge space are arranged in parallel along the laser optical axis.
Claim 46
Dependent Claim
19 words
A gas laser as set forth in claim 44, wherein the microwave transmission path is a square transmission path.
Claim 47
Dependent Claim
18 words
A gas laser as set forth in claim 44, wherein the microwave transmission path is a ridge waveguide.
Claim 48
Dependent Claim
19 words
A gas laser as set forth in claim 44, wherein the microwave transmission path is a delay transmission path.
Claim 49
Dependent Claim
24 words
A gas laser as set forth in claim 43, wherein the microwave transmission path and the plasma discharge space are coupled through a slit.
Claim 50
Dependent Claim
26 words
A gas laser as set forth in claim 43, wherein the microwave transmission path and the plasma discharge space are coupled through a plurality of holes.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1992-12-25 | 1993-06-26 | 1993-12-26 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1996-12-25 | 1997-06-26 | 1997-12-26 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2000-12-25 | 2001-06-26 | 2001-12-26 | $7700.00 | Window Closed / Lapsed |