US5463271A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Structure for enhancing electron emission from carbon-containing cathode
Assignee: Canon Inc
•
Filing: 1993-07-09
•
Granted: 1995-10-31
•
Expires: 2013-07-09
Abstract
Abstract A cathode structure contains electronegative atoms (22), which consist of oxygen and/or fluorine, chemically bonded to a carbon-containing cathode (10). Atoms (24R) of electropositive metal are chemically bonded to the electronegative atoms. The combination of the electropositive metal atoms and the electronegative atoms enhances the electron emissivity by reducing the work function.
Inventors
- 👤 Michael W. Geis
- 👤 John M. MaCaulay
- 👤 Jonathan C. Twichell
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 12:33
CPC Classifications
H; H01; H01J; H01J1/00; H01J1/02; H01J1/13; H01J1/14; H01J1/30; H01J1/304; H01J2201/00; H01J2201/30; H01J2201/304; H01J2201/30403; H01J2201/30426; H01J2329/00
Claims Analysis
Total Claims: 26
Claim 1
Independent Claim
41 words
An emissive cathode structure comprising: at least one carbon-containing electron-emissive cathode; electronegative atoms chemically bonded to the cathode where the electronegative atoms comprise at least one of oxygen and fluorine; and atoms of electropositive metal chemically bonded to the electronegative atoms.
Claim 2
Dependent Claim
41 words
An emissive cathode structure comprising: at least one carbon-containing electron-emissive cathode; electronegative atoms chemically bonded to the cathode where the electronegative atoms comprise at least one of oxygen and fluorine; and atoms of electropositive metal chemically bonded to the electronegative atoms.
Claim 3
Dependent Claim
38 words
A structure as in claim 1 further including regions of an alloy of atoms of noble metal and the electropositive metal situated over parts of the cathode in between parts of the cathode covered by the electronegative atoms.
Claim 4
Dependent Claim
68 words
An emissive cathode structure comprising: at least one carbon-containing cathode having an electron-emissive surface, the cathode being at least 50 atomic percent carbon along the electron-emissive surface; electronegative atoms chemically bonded to the cathode along a specified area of the electron-emissive surface, the electronegative atoms comprising at least one of oxygen and fluorine; and atoms of electropositive metal chemically bonded to the electronegative atoms along the specified area.
Claim 5
Dependent Claim
68 words
An emissive cathode structure comprising: at least one carbon-containing cathode having an electron-emissive surface, the cathode being at least 50 atomic percent carbon along the electron-emissive surface; electronegative atoms chemically bonded to the cathode along a specified area of the electron-emissive surface, the electronegative atoms comprising at least one of oxygen and fluorine; and atoms of electropositive metal chemically bonded to the electronegative atoms along the specified area.
Claim 6
Dependent Claim
17 words
A structure as in claim 3 wherein the cathode consists substantially of carbon along the electron-emissive surface.
Claim 7
Dependent Claim
25 words
A structure as in claim 3 wherein the carbon along the electron-emissive surface is primarily in at least one of diamond, graphite, and amorphous form.
Claim 8
Dependent Claim
22 words
A structure as in claim 3 wherein the carbon along the electron-emissive surface comprises at least one of n-doped and p-doped diamond.
Claim 9
Dependent Claim
25 words
A structure as in claim 3 wherein the carbon along the electron-emissive surface comprises diamond doped with at least one of nitrogen, lithium, and sulfur.
Claim 10
Dependent Claim
16 words
A structure as in claim 3 wherein the carbon along the electron-emissive surface comprises carbon-implanted diamond.
Claim 11
Dependent Claim
16 words
A structure as in claim 3 wherein the carbon along the electron-emissive surface comprises laser-modified diamond.
Claim 12
Dependent Claim
18 words
A structure as in claim 3 wherein the electronegative atoms largely form a monolayer over the specified area.
Claim 13
Dependent Claim
21 words
A structure as in claim 10 wherein the atoms of the electropositive metal largely form a monolayer over the specified area.
Claim 14
Dependent Claim
25 words
A structure as in claim 3 wherein the electropositive metal comprises at least one of lithium, sodium, potassium, rubidium, cesium, barium, scandium, yttrium and lanthanum.
Claim 15
Dependent Claim
32 words
A structure as in claim 3 further including regions of an alloy of atoms of gold and the electropositive metal situated over parts of the electron-emissive surface exclusive of the specified area.
Claim 16
Dependent Claim
16 words
A structure as in claim 3 wherein the cathode structure comprises a plurality of separate cathodes.
Claim 17
Dependent Claim
18 words
A structure as in claim 3 wherein the structure is capable of substantially withstanding exposure to atmospheric air.
Claim 18
Dependent Claim
24 words
A structure as in claim 3 wherein the structure is capable of substantially withstanding a temperature of at least 200° C. under high vacuum.
Claim 19
Dependent Claim
28 words
A structure as in claim 16 wherein the structure is capable of withstanding exposure to oxygen subsequent to being subjected to the temperature of at least 200° C.
Claim 20
Dependent Claim
23 words
A structure as in claim 3 wherein the structure is capable of substantially withstanding exposure to atmospheric air for at least 5 minutes.
Claim 21
Dependent Claim
23 words
A structure as in claim 3 wherein the structure is capable of substantially withstanding exposure to atmospheric air for at least 1 day.
Claim 22
Dependent Claim
29 words
A structure as in claim 3 wherein the structure is capable of substantially withstanding a temperature of at least 280° C. for at least 10 minutes under high vacuum.
Claim 23
Dependent Claim
29 words
A structure as in claim 3 wherein the structure is capable of substantially withstanding a temperature of at least 400° C. for at least 10 minutes under high vacuum.
Claim 24
Dependent Claim
18 words
A structure as in claim 1 wherein the structure is capable of substantially withstanding exposure to atmospheric air.
Claim 25
Dependent Claim
24 words
A structure as in claim 1 wherein the structure is capable of substantially withstanding a temperature of at least 200° C. under high vacuum.
Claim 26
Dependent Claim
28 words
A structure as in claim 23 wherein the structure is capable of withstanding exposure to oxygen subsequent to being subjected to the temperature of at least 200° C.
References Cited (Backward Citations)
US4411827A
Cited
US4663559A
Cited
US5019003A
Cited
US5202571A
Cited
US5089292A
Cited
US5190796A
Cited
US5180951A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1998-10-30 | 1999-05-01 | 1999-10-31 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2002-10-30 | 2003-05-01 | 2003-10-31 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2006-10-30 | 2007-05-01 | 2007-10-31 | $7700.00 | Window Closed / Lapsed |