US4468586A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Shaped electron emission from single crystal lanthanum hexaboride with intensity distribution
Assignee: International Business Machines Corp
•
Filing: 1981-05-26
•
Granted: 1984-08-28
•
Expires: 2001-05-26
Abstract
Abstract The shape of an electron beam emitted from an LaB 6 single crystal cathode can be controlled directly by shaping the cathode tip itself. The LaB 6 cathode is provided with a flat top surface which is substantially perpendicular to the emitted beam direction and which corresponds in shape to the shape of the beam desired. For a square beam the flat top surface is square in shape. The size of the shaped top surface and operating conditions are arranged such that emission of electrons occurs over substantially the entire shaped top surface with minimum emission from side regions of the tip adjacent to this shaped surface. In order to maximize emission from the shaped top surface, a crystallographic orientation is selected such that the shaped top surface exposes a relatively low work function crystal plane. Emission from side regions of the tip adjacent to the shaped high emission surface may be reduced by orienting such side regions very obliquely to the emitted beam axis. The side regions may also be flat surfaces, in which case emission from these flat side surfaces may be reduced by orienting the flat side surfaces such that they expose relatively high work function crystal plane.
Inventors
- 👤 Fritz-Jurgen Hohn
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 13:21
CPC Classifications
H; H01; H01J; H01J37/00; H01J37/02; H01J37/04; H01J37/06; H01J1/00; H01J1/02; H01J1/13; H01J1/15; H01J1/16
Claims Analysis
Total Claims: 60
Claim 1
Independent Claim
102 words
Apparatus for producing a shaped electron beam, comprising: a lanthanum hexaboride single crystal for emitting an electron beam along a beam axis, characterized in that said lanthanum hexaboride single crystal has a flat emitting surface perpendicular to said beam axis, said electron beam being primarily emitted from said flat surface and from substantially the entire area of said flat surface, said flat emitting surface exposing a crystal plane having a work function equal to or less than the work function of the (111) crystal plane, said flat emitting surface having a shape corresponding with the desired shape of the emitted electron beam.
Claim 2
Dependent Claim
102 words
Apparatus for producing a shaped electron beam, comprising: a lanthanum hexaboride single crystal for emitting an electron beam along a beam axis, characterized in that said lanthanum hexaboride single crystal has a flat emitting surface perpendicular to said beam axis, said electron beam being primarily emitted from said flat surface and from substantially the entire area of said flat surface, said flat emitting surface exposing a crystal plane having a work function equal to or less than the work function of the (111) crystal plane, said flat emitting surface having a shape corresponding with the desired shape of the emitted electron beam.
Claim 3
Dependent Claim
15 words
Apparatus as defined in claim 1 wherein said flat emitting surface has a non-circular shape.
Claim 4
Dependent Claim
15 words
Apparatus as defined in claim 2 wherein said flat emitting surface has a square shape.
Claim 5
Dependent Claim
34 words
Apparatus as defined in claim 1 wherein said flat emitting surface exposes a crystal plane selected from the group of crystal planes consisting of the (100), (110), (111), (321), (210), and (311) crystal planes.
Claim 6
Dependent Claim
32 words
Apparatus as defined in claim 1 wherein said flat emitting surface exposes a crystal plane selected from the group of crystal planes consisting of the (100), (110), (210), and (321) crystal planes.
Claim 7
Dependent Claim
24 words
Apparatus as defined in claim 1 wherein electron emission from the surface regions of the cathode adjacent to said flat emitting surface is suppressed.
Claim 8
Dependent Claim
35 words
Apparatus as defined in claim 6 wherein electron emission from surface regions of the cathode adjacent to said flat emitting surface is suppressed by orienting said adjacent surface regions oblique to said flat emitting surface.
Claim 9
Dependent Claim
22 words
Apparatus as defined in claim 7 wherein said adjacent surface regions are oriented at least 45 degrees from said flat emitting surface.
Claim 10
Dependent Claim
15 words
Apparatus as defined in claim 8 wherein said adjacent surface regions are primarily flat regions.
Claim 11
Dependent Claim
20 words
Apparatus as defined in claim 9 wherein said adjacent flat surface regions expose crystal planes having relatively high work functions.
Claim 12
Dependent Claim
26 words
Apparatus as defined in claim 10 wherein a relatively high work function is a work function more than the average work function for sintered lanthanum hexaboride.
Claim 13
Dependent Claim
24 words
Apparatus as defined in claim 1 wherein the emitting tip of said single crystal lanthanum hexaboride cathode has the shape of a truncated pyramid.
Claim 14
Dependent Claim
24 words
Apparatus as defined in claim 12 wherein said pyramid has four sides and a flat apex, said apex being the said flat emitting surface.
Claim 15
Dependent Claim
27 words
Apparatus as defined in claim 13 wherein said flat apex surface exposes a (100) crystal plane and the side surface of said pyramid expose (755) crystal planes.
Claim 16
Dependent Claim
28 words
Apparatus as defined in claim 1 and further characterized in that the emitted electron beam has a substantially uniform intensity distribution over the shaped region of said beam.
Claim 17
Dependent Claim
28 words
Apparatus as defined in claim 15 and further characterized in that the emitted electron beam has a substantially uniform angular distribution over the shaped region of said beam.
Claim 18
Dependent Claim
18 words
Apparatus as defined in claim 1 wherein said emitted electron beam has an intensity distribution which is non-gaussian.
Claim 19
Dependent Claim
21 words
Apparatus as defined in claim 1 wherein said emitted beam is further shaped by passing said beam through a shaped aperture.
Claim 20
Dependent Claim
51 words
Apparatus as defined in claim 18 wherein said shaped aperture has the same shape and about the same size as the shaped region of said emitted electron beam and is similarly oriented such that said shaped aperture tends to block electrons which are not within the shaped region of said beam.
Claim 21
Dependent Claim
100 words
Apparatus for producing a shaped electron beam, comprising: a lanthanum hexaboride single crystal cathode for emitting an electron beam along a beam axis, characterized in that said lanthanum hexaboride single crystal cathode has a flat surface perpendicular to said beam axis and said electron beam is primarily emitted from substantially the entire area of said flat surface, said flat emitting surface exposing a crystal plane having a work function equal to or less than the work function of the (111) crystal plane, said flat surface having a shape corresponding to some degree with the shape of said emitted electron beam.
Claim 22
Dependent Claim
100 words
Apparatus for producing a shaped electron beam, comprising: a lanthanum hexaboride single crystal cathode for emitting an electron beam along a beam axis, characterized in that said lanthanum hexaboride single crystal cathode has a flat surface perpendicular to said beam axis and said electron beam is primarily emitted from substantially the entire area of said flat surface, said flat emitting surface exposing a crystal plane having a work function equal to or less than the work function of the (111) crystal plane, said flat surface having a shape corresponding to some degree with the shape of said emitted electron beam.
Claim 23
Dependent Claim
15 words
Apparatus as defined in claim 20 wherein said flat emitting surface has a non-circular shape.
Claim 24
Dependent Claim
15 words
Apparatus as defined in claim 21 wherein said flat emitting surface has a square shape.
Claim 25
Dependent Claim
34 words
Apparatus as defined in claim 20 wherein said flat emitting surface exposes a crystal plane selected from the group of crystal planes consisting of the (100), (110), (111), (321), (210), and (311) crystal planes.
Claim 26
Dependent Claim
32 words
Apparatus as defined in claim 20 wherein said flat emitting surface exposes a crystal plane selected from the group of crystal planes consisting of the (100), (110), (210), and (321) crystal planes.
Claim 27
Dependent Claim
24 words
Apparatus as defined in claim 20 wherein electron emission from the surface regions of the cathode adjacent to said flat emitting surface is suppressed.
Claim 28
Dependent Claim
35 words
Apparatus as defined in claim 25 wherein electron emission from surface regions of the cathode adjacent to said flat emitting surface is suppressed by orienting said adjacent surface regions oblique to said flat emitting surface.
Claim 29
Dependent Claim
22 words
Apparatus as defined in claim 26 wherein said adjacent surface regions are oriented at least 45 degrees from said flat emitting surface.
Claim 30
Dependent Claim
15 words
Apparatus as defined in claim 27 wherein said adjacent surface regions are primarily flat regions.
Claim 31
Dependent Claim
20 words
Apparatus as defined in claim 28 wherein said adjacent flat surface regions expose crystal planes having relatively high work functions.
Claim 32
Dependent Claim
26 words
Apparatus as defined in claim 29 wherein a relatively high work function is a work function more than the average work function for sintered lanthanum hexaboride.
Claim 33
Dependent Claim
24 words
Apparatus as defined in claim 20 wherein the emitting tip of said single crystal lanthanum hexaboride cathode has the shape of a truncated pyramid.
Claim 34
Dependent Claim
24 words
Apparatus as defined in claim 31 wherein said pyramid has four sides and a flat apex, said apex being the said flat emitting surface.
Claim 35
Dependent Claim
27 words
Apparatus as defined in claim 32 wherein said flat apex surface exposes a (100) crystal plane and the side surface of said pyramid expose (755) crystal planes.
Claim 36
Dependent Claim
28 words
Apparatus as defined in claim 20 and further charaterized in that the emitted electron beam has a substantially uniform intensity distribution over the shaped region of said beam.
Claim 37
Dependent Claim
28 words
Apparatus as defined in claim 34 and further characterized in that the emitted electron beam has a substantially uniform angular distribution over the shaped region of said beam.
Claim 38
Dependent Claim
18 words
Apparatus as defined in claim 20 wherein said emitted electron beam has an intensity distribution which is non-gaussian.
Claim 39
Dependent Claim
21 words
Apparatus as defined in claim 20 wherein said emitted beam is further shaped by passing said beam through a shaped aperture.
Claim 40
Dependent Claim
51 words
Apparatus as defined in claim 37 wherein said shaped aperture has the same shape and about the same size as the shaped region of said emitted electron beam and is similarly oriented such that said shaped aperture tends to block electrons which are not within the shaped region of said beam.
Claim 41
Independent Claim
102 words
A method of shaping the electron beam emitted from a single crystal lanthanum hexaboride cahtode, comprising the steps of: forming a flat surface on the emitting tip of the single crystal lanthanum hexaboride cathode, said flat surface having a shape corresponding with the desired shape of the emitted electron beam; operating the single crystal lanthanum hexaboride single crystal cathode at conditions such that an electron beam is emitted primarily from substantially the entire area of said flat surface, said flat surface exposing a crystal plane having a work function equal to or less than the work function of the (111) crystal plane.
Claim 42
Independent Claim
102 words
A method of shaping the electron beam emitted from a single crystal lanthanum hexaboride cahtode, comprising the steps of: forming a flat surface on the emitting tip of the single crystal lanthanum hexaboride cathode, said flat surface having a shape corresponding with the desired shape of the emitted electron beam; operating the single crystal lanthanum hexaboride single crystal cathode at conditions such that an electron beam is emitted primarily from substantially the entire area of said flat surface, said flat surface exposing a crystal plane having a work function equal to or less than the work function of the (111) crystal plane.
Claim 43
Dependent Claim
16 words
A method as defined in claim 39 wherein the shape of said flat surface is non-circular.
Claim 44
Dependent Claim
16 words
A method as defined in claim 40 wherein the shape of said flat surface is square.
Claim 45
Dependent Claim
34 words
A method as defined in claim 39 wherein said flat surface exposes a crystal plane selected from the group of crystal planes consisting of the (100), (110), (111), (321), (210), and (311) crystal planes.
Claim 46
Dependent Claim
32 words
A method as defined in claim 39 wherein said flat surface exposes a crystal plane selected from a group of crystal planes consisting of the (100), (110), (210), and (321) crystal planes.
Claim 47
Dependent Claim
25 words
A method as defind in claim 39 wherein electron emission from the surface regions of the cathode adjacent to said flat emitting surface is suppressed.
Claim 48
Dependent Claim
36 words
A method as defined in claim 44 wherein electron emission from surface regions of the cathode adjacent to said flat emitting surface is suppressed by orienting said adjacent surface regions oblique to said flat emitting surface.
Claim 49
Dependent Claim
23 words
A method as defined in claim 45 wherein said adjacent surface regions are oriented at least 45 degrees from said flat emitting surface.
Claim 50
Dependent Claim
16 words
A method as defined in claim 46 wherein said adjacent surface regions are primarily flat regions.
Claim 51
Dependent Claim
21 words
A method as defined in claim 47 wherein said adjacent flat surface regions expose crystal planes havin relatively high work functions.
Claim 52
Dependent Claim
27 words
A method as defined in claim 48 wherein a relatively high work function is a work function more than the average work function for sintered lanthanum hexaboride.
Claim 53
Dependent Claim
25 words
A method as defined in claim 39 wherein the emitting tip of said single crystal lanthanum hexaboride cathode has the shape of a truncated pyramid.
Claim 54
Dependent Claim
25 words
A method as defined in claim 50 wherein said pyramid has four sides and a flat apex, said apex being the said flat emitting surface.
Claim 55
Dependent Claim
28 words
A method as defined in claim 51 wherein said flat apex surface exposes a (100) crystal plane and the side surface of said pyramid expose (755) crystal planes.
Claim 56
Dependent Claim
29 words
A method as defined in claim 39 and further characterized in that the emitted electron beam has a substantially uniform intensity distribution over the shaped region of said beam.
Claim 57
Dependent Claim
29 words
A method as defined in claim 53 and further characterized in that the emitted electron beam has a substantially uniform angular distribution over the shaped region of said beam.
Claim 58
Dependent Claim
19 words
A method as defined in claim 39 wherein said emitted electron beam has an intensity distribution which is non-gaussian.
Claim 59
Dependent Claim
22 words
A method as defined in claim 39 wherein said emitted beam is further shaped by passing said beam through a shaped aperture.
Claim 60
Dependent Claim
52 words
A method as defined in claim 56 wherein said shaped aperture has the same shape and about the same size as the shaped region of said emitted electron beam and is similarly oriented such that said shaped aperture tends to block electrons which are not within the shaped region of said beam.
References Cited (Backward Citations)
GB1210007A
Cited
US3631290A
Cited
GB1433944A
Cited
JPS5141951A
Cited
US4055780A
Cited
JPS5230151A
Cited
JPS5231650A
Cited
US4054946A
Cited
JPS5451473A
Cited
JPS5524371A
Cited
JPS5588233A
Cited
US4363995A
Cited
EP0030465A1
Cited
JPS5693244A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1987-08-28 | 1988-02-27 | 1988-08-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1991-08-28 | 1992-02-27 | 1992-08-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1995-08-28 | 1996-02-27 | 1996-08-28 | $7700.00 | Window Closed / Lapsed |