Information
-
Patent Grant
-
6806627
-
Patent Number
6,806,627
-
Date Filed
Thursday, April 11, 200222 years ago
-
Date Issued
Tuesday, October 19, 200419 years ago
-
Inventors
-
Original Assignees
-
Examiners
Agents
-
CPC
-
US Classifications
Field of Search
US
- 313 113
- 313 567
- 313 581
- 313 601
- 313 595
- 313 303
- 361 117
- 361 120
-
International Classifications
-
Abstract
A probe stabilized arc discharge lamp including a base portion, a window spaced from the base portion, a side wall interconnecting the base portion with the window. The side wall, the base portion, and the window define a chamber. A first electrode is disposed vertically in the chamber and extends outwardly through the base portion. A second electrode is also disposed vertically in the chamber and is spaced from the first electrode. The second electrode extends outwardly through the base portion. The first and second electrodes define an arc gap. There is also at least one trigger probe extending to or proximate to the arc gap for triggering an arc in the arc gap. Also, a reflector is disposed about the arc gap for directing radiation generated by the arc out the window. A sparker may also be provided.
Description
FIELD OF THE INVENTION
This invention relates to a probe stabilized arc discharge lamp usually operated in a pulsed mode.
BACKGROUND OF THE INVENTION
Arc discharge lamps are used for spectroscopy, as sources of light with a response over a broad spectrum, and for many other uses. Most arc discharge lamps have several components in common: an arc gap defined by two opposing electrodes, one of which is a cathode, another being an anode, disposed in a gas (e.g., Xenon) filled chamber. A reflector is typically disposed about the arc gap and light emitted at the arc gap is directed by the reflector out a window.
There are two basic types of arc discharge lamps: those designed to operate in a continuous mode and those designed to be operated in a pulsed mode. Typically, arc discharge lamps designed to be operated in a continuous mode cannot generally be operated in a pulsed mode because of, inter alia, the differences in the internal pressures generated, the lack of a trigger probe in continuously operated lamps, the increased cathode and anode sputtering which occurs in the pulse mode and the criticality of cathode and anode alignment in pulsed mode lamps.
Therefore, continuous mode lamps, if operated in a pulsed mode, would suffer from a short useful life and a less than desirable output. There are also two basic continuous mode lamp designs: those with horizontally disposed cathodes and anodes, and those with vertically disposed cathodes and anodes. By horizontally disposed electrodes, we mean electrodes disposed across the light path from the arc gap to the reflector and out through the window. By vertically disposed electrodes, we mean electrodes extending in the direction of the light path. The vertically disposed cathode and anode design advantageously has an improved lambertian distribution because the arc gap can be set at the focal point of the reflector and there is a minimum of structure disposed in the light path between the arc gap and the window.
Today, however, all successful pulsed mode arc discharge lamp designs have included only horizontally disposed electrodes. But, because of the benefits of vertically disposed electrodes in continuous mode arc discharge lamps, as discussed above, those skilled in the art have long desired a pulsed mode arc discharge lamp with vertically disposed electrodes. Due to the required physical differences between pulsed mode and continuous mode arc discharge lamps, however, the design of a continuous mode arc discharge lamp with vertically disposed electrodes has not translated into a successful pulsed mode arc discharge lamp design with vertically disposed electrodes.
Disclosed herein is a probe stabilized short arc discharge lamp designed to be operated in a pulse mode and advantageously having vertically disposed electrodes made possible, inter alia, by unique cathode and anode configurations, a uniquely designed trigger probe electrode, a preionization device called a sparker, monolithically constructed ceramic housing with a reflector integrally disposed thereon, a novel cathode jig for co-axially aligning and correctly distancing the cathode with respect to the anode, and a novel trigger probe jig for orienting the probe tip with respect to the arc gap. And, preferably, all of the electrode connections extend through the base of the lamp.
SUMMARY OF THE INVENTION
It is therefore an object of this invention to provide a high output, long life arc discharge lamp designed to be operated in a pulsed mode.
It is a further object of this invention to provide such an arc discharge lamp with vertically disposed electrodes.
It is a further object of this invention to provide such an arc discharge lamp with integrated optical components.
It is a further object of this invention to provide such an arc discharge lamp which can be operated at a high pressure.
It is a further object of this invention to provide a more efficient arc discharge lamp.
It is a further object of this invention to provide such an arc discharge lamp with improved lambertian distribution.
It is a further object of this invention to provide an arc discharge lamp with increased stability.
It is a further object of this invention to provide an arc discharge lamp which requires less power to operate for a given output.
It is a further object of this invention to provide such an arc discharge lamp which lasts longer.
It is a further object of this invention to provide such an arc discharge lamp which does not exhibit excessive sputtering.
It is a further object of this invention to provide such an arc discharge lamp which does not suffer from breakdown potentials.
It is a further object of this invention to provide an arc discharge lamp which is single ended: that is, all the electrical connections extend from the base portion of the lamp.
It is a further object of this invention to provide such an arc discharge lamp which is relatively easy and inexpensive to manufacture.
It is a further object of this invention to provide such an arc discharge lamp which can be repeatedly assembled in an exacting configuration.
It is a further object of this invention to provide a cathode jig for co-axially aligning and correctly distancing the cathode with respect to the anode.
It is a further object of this invention to provide a trigger probe jig which correctly orients the trigger probe tip with respect to the arc gap.
In this invention, the advantages of vertically disposed electrodes are realized in a pulsed mode arc discharge lamp by a uniquely configured anode and cathode, the presence of a trigger probe, a preionization device call a sparker, a monolithically constructed base and side wall lamp housing portion typically made of ceramic material, an integral reflector constructed directly on the ceramic housing, the use of a novel cathode jig which assists manufacturing personnel in co-axially aligning and correctly distancing the cathode with respect to the anode, and a novel trigger probe jig which assists manufacturing personnel in correctly orienting the probe tip with respect to the arc gap.
This invention features a probe stabilized arc discharge lamp. Typically, the lamp includes a monolithic base portion and side wall portion defining a concave surface, a window spaced from the base portion and sealed with respect to the side wall portion defining a chamber, a gas in the chamber, and a reflector disposed on or integral with the concave surface. A first electrode is usually centrally disposed in the base portion and has a distal end which extends outwardly from the base portion. In the preferred embodiment, the first electrode includes an anode support and an anode vertically supported by the anode support. Also in the preferred embodiment, there is a second electrode also having a distal end which extends outwardly from the base portion. The second electrode preferably includes a cathode support extending vertically upward through the side wall portion, a cathode support arm extending horizontally inward from the cathode support, and a cathode extending vertically downward from the cathode support arm to a location spaced from the anode to define an arc gap at the focal point of the reflector. Finally, a third electrode is preferably included which also has a distal end extending outwardly from the base portion. The third electrode extends vertically upward through the side wall portion and has a reduced circumference region or probe support pin proximate the side wall portion. The third electrode further includes a trigger probe extending from the reduced circumference region to or proximate to the arc gap for triggering an arc in the arc gap between the anode and the electrode.
In one example, the base portion and the side wall portion are made of a ceramic material, the anode support includes a distal seat for receiving the anode, the anode support is made of Kovar, the anode has a flat distal surface with no chamfers, the cathode support is made of Kovar, the cathode support arm is made of molybdenum, the cathode is made of a material including tungsten and the cathode has a pointed and tapered distal (e.g., 60° tapered) end.
The cathode support may have a recess on a distal end thereof for receiving one end of the cathode support arm and the cathode then has a recess on a proximal end thereof for receiving the other end of the cathode support arm.
In one preferred embodiment, third electrode includes a support extending upward through the side wall portion, a probe pin extending upward from the support, the probe pin having a reduced circumference, and a probe which extends from the probe pin. The support typically includes seat therein for receiving the probe pin.
The window may be made of sapphire, may be flat or convex in shape, and may include a transparent member surrounded by a collar which is secured to the side wall portion. Further included may be a shield member extending about the collar and a portion of the side wall. In one embodiment, the side wall portion includes an integral support for the window.
The reflector may be parabolic or elliptical in shape and preferably terminates on the side wall portion at a location spaced from the cathode support and also at a location spaced from the reduced circumference region of the third electrode. Typically, the trigger probe has a pointed distal tip offset from the arc gap.
The probe stabilized arc discharge lamp of this invention may comprise a base portion; a window spaced from the base portion; a side wall interconnecting the base portion with the window such that the side wall, the base portion, and the window define a gas containing chamber; a first electrode disposed vertically in the chamber and extending outwardly through the base portion; a second electrode also disposed vertically in the chamber and extending outwardly through the base portion, the second electrode spaced from the first electrode defining an arc gap between distal ends of the first and second electrodes; a trigger probe extending to or proximate to the arc gap for triggering an arc in the arc gap; and a reflector disposed about the arc gap for directing radiation generated by the arc out the window.
Preferably, the base portion and the side wall are monolithic in construction and define a concave surface surrounding the arc gap. The base portion and the side wall are typically made of ceramic material and the reflector is preferably an integral part of the concave surface.
The second electrode preferably includes a cathode support extending up through the side wall, a cathode support arm extending horizontally from the cathode support inwardly over the arc gap, and a cathode extending vertically downward from the cathode support arm. The cathode support may have a recess on a distal end thereof for receiving one end of the cathode support arm and the cathode then has a recess on a proximal end thereof for receiving the other end of the cathode support arm.
The trigger probe is preferably disposed on one end on a probe support electrode which extends outwardly thought the base portion. The probe support electrode includes a seat on a distal end thereof, the lamp further including a reduced circumference trigger probe support pin supported on one end by the seat in the probe support electrode. The trigger probe extends inwardly and downward from the trigger probe support pin.
The lamp preferably also includes a sparker assembly including a lead disposed in the chamber, an insulative support for the lead attached to the cathode support arm, and an electrical conductor extending to and within the gas fill tube.
A probe stabilized arc discharge lamp according to this invention includes a base portion; a window spaced from the base portion; a side wall interconnecting the base portion with the window, the side wall, the base portion, and the window defining a chamber; a gas in the chamber; a first electrode disposed vertically in the chamber and extending outwardly through the base portion; a second electrode also disposed vertically in the chamber and extending outwardly through the base portion, the second electrode spaced from the first electrode defining an arc gap between the distal ends of the first and second electrodes; a trigger probe extending to or proximate to the arc gap for triggering an arc in the arc gap; and a reflector disposed about the arc gap for directing radiation generated by the arc out the window.
This invention also features a cathode jig for a probe stabilized arc discharge lamp, the cathode jig comprising a multiple piece body having a first section with an internal channel for receiving an anode therein and a second section with a concave cavity on the distal end thereof for receiving the distal end of a cathode; the first section having a circumference sized to coaxially align the cathode with the anode when the first section is disposed over the anode; and the second section having a length sized to correctly distance the distal end of the cathode from the distal end of the anode. In one example, the multiple piece body is divided into two pieces.
This invention also features a trigger probe jig for a probe stabilized arc discharged lamp, the trigger probe jig comprising a multiple piece body having an internal channel for receiving an anode therein and a distal end with a rest defined thereon for receiving and supporting the distal end of the trigger probe, the body having a circumference and a length sized to correctly orient the trigger probe tip with respect to the arc gap between the cathode and the anode.
BRIEF DESCRIPTION OF THE DRAWINGS
Other objects, features and advantages will occur to those skilled in the art from the following description of a preferred embodiment and the accompanying drawings, in which:
FIG. 1
is a schematic cross sectional view of one embodiment of the probe stabilized arc discharge lamp of the subject invention;
FIG. 2
is a schematic view showing the lambertian distribution of a prior art arc discharge lamp with horizontally disposed electrodes;
FIG. 3
is a three dimensional schematic top view showing the primary components associated with the probe stabilized arc discharge lamp of the subject invention;
FIG. 4
is a cross sectional view of the housing and electrode portions of the probe stabilized arc discharge lamp of the subject invention;
FIG. 5
is a cross sectional view of the housing portion of the probe stabilized arc discharge lamp of this invention;
FIG. 6
is a top view of the housing shown in
FIG. 5
;
FIG. 7
is a cross sectional view of an anode support component of the arc discharge lamp of this invention;
FIG. 8
is a side view of an anode according to one embodiment of this invention;
FIG. 9
is a cross sectional view of the anode cup component of the arc discharge lamp of this invention;
FIG. 10
is a side view of the cathode pin component of the arc discharge lamp according to the preferred embodiment of this invention;
FIG. 11
is another side view of the cathode pin component of the arc discharge lamp of this invention;
FIG. 12
is a three dimensional schematic view showing the cathode support arm component according to the preferred embodiment of the arc discharge lamp of this invention;
FIG. 13
is a schematic front view of the cathode according to the preferred embodiment of the arc discharge lamp of this invention;
FIG. 14
is a cross sectional view of the probe support according to the preferred embodiment of the arc discharge lamp of this invention;
FIG. 15
is a side view of the probe support pin of this invention;
FIG. 16
is a schematic view of the trigger probe of this invention;
FIG. 17
is a schematic view of the sparker assembly of this invention;
FIGS. 18 and 19
are cross sectional views showing two embodiments of the window support element of the arc discharge lamp of this invention;
FIG. 20
is a schematic cross sectional view showing the Kovar ring component of the arc discharge lamp of this invention;
FIG. 21
is a cross sectional view showing another embodiment of a probe stabilized arc discharge lamp in accordance with this invention;
FIG. 22
is a schematic cross sectional view showing another embodiment of a probe stabilized arc discharge lamp in accordance with this invention;
FIG. 23
is a schematic cross sectional view showing the use of the cathode jig of this invention in place over the anode and supporting the cathode during the assembly of a probe stabilized arc discharge lamp;
FIG. 24
is a schematic three dimensional view showing the two sections of the cathode jig shown in
FIG. 20
;
FIG. 25
is a cross-sectional view of the cathode jig shown in
FIGS. 23-24
;
FIG. 26
is a top view of the cathode jig shown in
FIG. 25
;
FIG. 27
is a schematic cross sectional view showing the use of the trigger probe jig during the assembly of probe stabilized arc discharge lamps in accordance with this invention;
FIG. 28
is a cross sectional view of the trigger probe jig shown in
FIG. 27
;
FIG. 29
is a top view of the trigger probe jig shown in
FIG. 28
; and
FIG. 30
is a schematic cross sectional view of the arc discharge lamp of the subject invention showing the sparker assembly thereof.
DISCLOSURE OF THE PREFERRED EMBODIMENT
Probe stabilized arc discharge lamp
10
,
FIG. 1
, in one example, preferably includes a housing comprising monolithic base
12
and side wall
14
portions defining concave (parabolic or elliptical) surface
16
. Typically, monolithic portions
12
and
14
are made of ceramic because of its electrical insulative properties, ability to withstand high temperatures, moldability, low cost, machineability, and a coefficient of thermal expansion which closely matches a coefficient of thermal expansion of the material of the optical components of lamp
10
including window
18
, its metalization
20
, and the material of window collar
22
. In this embodiment, Kovar window collar
22
is supported on side wall portion
14
as shown at
15
and Kovar shield
17
extends about collar
22
and a portion of side wall
14
as shown for assembly purposes and for electromagnetic interference protection. In other embodiments, the material of base portion
12
and wall portion
14
could be made Kovar, for example.
Window
18
, made of, for example, sapphire, glass, magnesium fluoride, and the like (depending on the wavelengths desire to be emitted from lamp
10
), is sealed with respect to side wall
14
defining gas (e.g., Xenon) filled chamber
24
. Reflector
26
, (made of, e.g., aluminum) is disposed on concave surface
16
by sputtering, deposition, or electroplating techniques, for example, and has a focal point preferably defined at arc gap
28
.
First electrode
30
is shown centrally disposed in base portion
12
and has distal end
32
which extends outward from base portion
12
. First electrode
30
includes vertical anode
34
and anode support
36
with distal anode seat
38
. In one example, anode
34
is made of 2% thoriated or pure tungsten and anode support
36
is made of Kovar. Anode
34
typically has a flat distal surface
40
.
Second electrode
50
also typically has a distal end
52
which extends outwardly from base portion
12
and includes cathode support
54
which extends vertically up through side wall portion
14
, cathode support arm
56
which extends horizontally inward from cathode support
54
, and cathode
58
which extends vertically downward from cathode support arm
56
to a location spaced from anode
34
to thus define arc gap
28
at the focal point of reflector
26
. In one embodiment, cathode support
54
is made of Kovar, cathode support arm
56
is made of molybdenum, and cathode
58
is made of
805
dense tungsten impregnated with low work function material, for example barium (BA), calcium (CA), and Aluminate (Al
2
O
3
). Cathode
58
preferably has tapered pointed distal end
60
(taper
62
, in one example, was 60 degrees).
Third electrode
70
also has distal end
72
which preferably extends outwardly from base portion
12
. Thus, all the electrodes, in this embodiment, extend from base portion
12
resulting in a single ended lamp. Third electrode
70
includes trigger probe support
74
extending vertically upward through side wall portion
14
, typically opposite of cathode support
54
. Reduced diameter trigger probe pin
76
supports trigger probe
78
in a cantilevered manner and probe
78
extends to or proximate to arc gap
28
for triggering an arc in the arc gap between anode
34
and cathode
58
.
Reduced diameter trigger probe support pin
76
, disposed proximate side wall
14
, reduces the breakdown potential between reflector
16
and third electrode
70
and note that reflector
16
preferably terminates on side wall portion
14
at a location
80
spaced 0.060 inches from the edge of probe support pin
76
hole
75
to further reduce the breakdown potential between reflector
16
and third electrode
70
. The same is true at location
82
: reflector
26
terminates on side wall portion
14
at a location 0.060 inches spaced from the cathode support
54
hole. Trigger probe support
74
is typically made of Kovar, trigger probe support pin
76
is typically made of molybdenum, and trigger probe
78
is typically made of tungsten and has distal pointed tip
86
. Pointed tip
86
and the fact that it is preferably positioned offset 0.004 inches from centerline of arc gap
28
prevents sputtering of cathode material from cathode
58
onto probe tip
86
. Each electrode
30
,
50
, and
70
is typically positioned in base portion
12
via cups
90
,
92
, and
94
, respectively, which provide stress relief. Lamp
10
further typically includes sparker assembly
400
attached to cathode support arm
56
providing a source of light and ultraviolet photons which facilitate ionization of the xenon in chamber
24
and in arc gap
28
resulting in a lower trigger breakdown potential and improved pulse-to-pulse discharge stability.
In the design of
FIG. 1
, the lambertian distribution of the radiation from arc gap
28
is as shown by the dotted lines at
100
which, in combination with the arc gap
28
being uniquely locatable at the focal point of reflector
26
, results in a higher output (up to 20 times) than prior art pulsed mode arc discharge lamps with horizontally disposed electrodes
110
and
120
,
FIG. 2
which create a lambersion distribution as shown by the dotted lines at
122
. In such a design, reflector
124
must be positioned below electrodes
110
and
120
and occupies an inordinate amount of space in the base portion of the lamp.
In general, those skilled in the art have long desired a pulsed mode arc discharge lamp design with vertically disposed electrodes because such a design exhibits a higher output, longer life, and is more robust. Although continuous mode arc discharge lamps with vertical electrodes are known in the art, they cannot be operated in a pulse mode because, inter alia, of the differences in the internal pressures generated, the lack of a trigger probe in continuously operated arc discharge lamps, the increased cathode and anode sputtering which occurs in a pulse mode, and the criticality of the cathode and anode alignment in pulsed mode arc discharge lamps. Thus, as delineated in the Background section above, the design of a continuous mode arc discharge lamp with vertically disposed electrodes has not translated into a successful pulsed mode arc discharge lamp with vertically disposed electrodes.
Arc discharge lamp
10
,
FIG. 1
, however, is uniquely designed to be operated in a pulsed mode and uniquely has vertically disposed electrodes
30
,
50
, and
70
and, in particular, vertically disposed anode
34
and cathode
58
made possible, inter alia, by the unique configuration of cathode
58
and anode
54
, the presence and design of trigger probe electrode
78
, preionization sparker
400
, monolithically constructed base
12
and side wall portions
14
with reflector
16
thereon, a novel cathode jig for co-axially aligning and precisely distancing cathode
58
with respect to anode
34
, and a novel trigger probe jig for precisely orienting the tip of trigger probe
78
with respect to arc gap
28
as discussed infra.
Lamp
10
,
FIG. 1
, is specifically designed to be operated in a pulse mode and, due to vertically disposed cathode
58
and anode
34
, the arc from arc gap
28
can be located at the focal point of reflector
26
resulting in a more efficient lamp with an improved lambertian distribution and a minimum of structure blocking the light path from arc gap
28
out through window
18
. Single cathode support arm
56
advantageously blocks less light than the ring strut designs of the prior art. The single ended design shown is also advantageous. Due to probe
78
, the light output pulse-to-pulse stability of lamp
10
is approximately one percent compared to lamps without probes having a stability of approximately ten percent. Reduced diameter probe pin
76
and the termination of reflector
26
short of probe pin
76
and cathode support
54
increases the breakdown potential between probe pin
76
and reflector
26
. Due to the use of 80% dense tungsten, plus low work function materials for cathode
58
, the result is a lower work function cathode with less susceptibility to sputtering and which accommodates high peak currents. Furthermore, the pointed end
86
of probe
78
and its position removed from arc gap
28
(off axis with respect to the longitudinal axis defined by cathode
58
and anode
34
) prevents sputtering onto probe tip
86
. This design also avoids interference with the arc resulting in a more stable longer life lamp.
Cathode
58
with a distal converging side wall as shown at
60
and
62
is a particularly efficient design: flat cathode tips exhibit good useful lives but produce poor discharge stability while sharply pointed cathode tips produce a better arc but exhibit too short a useful life due to erosion. Anode
34
tip
40
, in contrast, is typically made substantially flat for stability and thermal considerations.
Finally, as stated above, the use of a unitary ceramic body for the housing forming base portion
12
and side wall portion
14
with reflector
26
in combination with the features above results in a long life, high output lamp.
FIG. 3
shows lamp
10
,
FIG. 1
without the window and reflector. Gas port
130
is also shown which is in communication with a conduit or fill tube, not shown, for filling chamber
24
with Xenon as is known in the art. In the prior art, the fill tube was pinched off after filling the chamber with gas. In this invention, sparker assembly
400
includes lead
402
extending from insulative ceramic support
404
attached to cathode support arm
56
and electrical conductor
406
which extends as shown to fill part
130
and down into the gas fill tube as discussed with reference to
FIG. 30
below.
FIG. 4
shows, in more detail, the electrodes and the ceramic housing before the addition of the trigger probe, the cathode, the anode support arm, the sparker assembly, and the window. In one example, the lamp was approximately one inch in diameter and approximately 0.8 inches tall.
FIG. 5
shows the ceramic housing alone with the bores for the electrodes and the electrode cups.
FIG. 6
shows probe support
74
orifice
75
, orifice
130
for the gas fill tube, and orifice
77
for anode support
54
in side wall
14
.
FIG. 7
shows anode support
36
which, in one example, was 0.080 inches in diameter and 0.6 inches long. Seat
38
was 0.040 inches in diameter and 0.040 inches deep. Anode
34
is shown in
FIG. 8 and
, in one example, was 0.325 inches long, and 0.080 inches in diameter. Tapered end
35
is received in anode seat
38
,
FIG. 7 and
, in one example, was 0.040 inches in diameter and 0.035 inches long. Distal end
40
,
FIG. 8
of anode
34
may have a slight corner chamfer as shown 0.010×45 degrees. Anode cup
90
is shown in FIG.
9
and in one example was 0.271 inches outside diameter with an anode receiving orifice
91
0.0815 inches in diameter. The height of anode cup
90
was 0.195 inches and the wall thickness was 0.0150 inches. Cups
92
and
94
,
FIG. 1
may be similarly constructed.
FIG. 10
shows cathode support
54
combined with cathode support cup
92
. Cathode support
54
was 1.330 inches long and 0.080 inches in diameter. Distal end
55
includes slot
57
for receiving cathode support arm
56
,
FIG. 1
therein. Cathode support
54
is also shown in
FIG. 11
without the cup. Slot
57
was, in one embodiment, 0.060 inches deep and 0.019 inches wide. Cathode support arm
56
,
FIG. 12
is typically a lengthy rectangular cross section bar 0.531 inches long, 0.060 inches wide, and 0.015 inches thick. Cathode
58
,
FIG. 13
then includes slot
59
on proximal end
61
thereof 0.019 inches wide and 0.08 inches deep. Cathode
58
itself is 0.402 inches long and the radius of distal tip
53
is 0.005 inches. In this specific example, the body of cathode
58
was 0.080 inches in diameter.
During assembly, cathode support
54
,
FIG. 4
is secured in base portion
12
. Slot
57
,
FIG. 10
of cathode support
54
, then receives one end of cathode support arm
56
while slot
59
,
FIG. 13
, of cathode
58
then receives the other end of cathode support arm
56
. This construction, in combination with the cathode alignment jig of this invention discussed below, greatly facilitates the positioning of the cathode and alignment of the cathode with respect to the anode during assembly of the lamp. Once the alignment is complete, cathode support arm
56
is secured to cathode support
54
by a laser weld and cathode
58
is secured to cathode support arm
56
by brazing.
Probe support
74
,
FIG. 14
, again in one specific example, was 1.1 inches long, 0.080 inches in diameter and includes probe support pin seat
65
0.030 inches deep and 0.018 inches in diameter. Probe support pin
76
,
FIG. 15
was a round bar 0.4 inches long and 0.015 inches in diameter. Proximal end
67
is received in seat
65
,
FIG. 14
of probe support
74
. 0.015 inch diameter tungsten probe
78
,
FIG. 16
was approximately 0.5 inches long and tip portion
86
was 0.042 inches long with a 20° taper and a roundness of 0.005 inches. The proximal end of probe
78
is secured to the distal end of probe support pin
76
,
FIG. 1
by welding. Sparker assembly
400
,
FIG. 17
includes lead
402
extending from insulative ceramic support
404
attached to cathode support arm
56
.
Window support
22
,
FIG. 18
again in one specific example, has at an outside diameter of 1.239 inches and a window support diameter
69
of 0.780 inches. Window support
22
was 0.125 inches thick and made of Kovar. Opening
23
serves as a heat choice when window support
22
is welded to portion
15
of lamp
10
and shield
17
is welded in place. 1.239 inch diameter Kovar window collar
210
,
FIG. 19
, in another embodiment, may also be used. Window collar
210
, in one specific example was 0.255 inches tall, has an outside diameter 1.239 inches and an inside diameter of 1.006 inches.
Kovar ring
17
,
FIG. 20
had an outside diameter of 1.300 inches, an inside diameter of 1.250 inches, and was 0.275 inches tall. The specific dimensions of the various components of the arc discharge lamp described above, however, are not limitations of the invention claimed herein.
Lamp
10
′,
FIG. 21
advantageously includes side wall
14
′ with integral support
200
for window
18
. Window
18
may include circumferencial edge metalization braized directly to the ceramic material of side wall
14
′ owing to the single ended design of the lamp. In this design, shield
17
,
FIG. 1
maybe eliminated. Otherwise, the other components of lamp
10
′,
FIG. 17
are the same as or similar to lamp
10
, FIG.
1
.
Thus far, the windows disclosed have been flat but this is not a necessary limitation of the subject invention. In the design shown in
FIG. 22
, window
18
′ has a convex shape and includes central transparent region
220
supported by support member
222
itself supported by housing supports
200
.
FIGS. 23 through 26
show cathode alignment jig
300
which includes stainless steel body
302
made in two pieces
304
and
306
each together defining section
308
with a 0.081-0.083 inch diameter internal channel
301
for receiving anode
34
therein and distal end section
310
with concave 120° 0.045 inch deep cavity
312
which receives the distal end of cathode
58
therein. The 0.190-0.194 inch outer diameter of section
308
is sized to coaxially align cathode
58
with respect to anode
34
and thus its diameter is slightly smaller then the diameter of the orifice in base portion
12
surrounding anode
34
. Second section
320
has a length which correctly distances the distal end of cathode
58
from the distal end of anode
34
to define the appropriate arc gap length.
Preferably, anode
34
,
FIG. 23
is placed in base portion
12
and both sections
304
and
306
of cathode jig
300
are typically secured together using tape, for example. Jig
300
is then placed over anode
34
as shown. Next, cathode
58
is placed in cavity
312
and supported thereby as cathode support arm
56
,
FIG. 1
is secured to both cathode
58
and cathode support
54
using the slotted arrangement previously discussed with reference to
FIGS. 10-13
. Then, the tape about jig
300
is cut and the two pieces
304
and
306
removed from about anode
34
and cathode
58
. Thus, the slotted design of
FIGS. 10-13
in conjunction with jig
300
,
FIGS. 23-26
provide for concentric alignment of cathode
58
with respect to anode
34
and the correct, reproducible spacing of the arc gap between the cathode and the anode.
Trigger probe jig
350
,
FIGS. 27-29
is used after the assembly of the cathode and the anode to correctly position the distal tip of trigger probe
78
with respect to arc gap
28
. Trigger probe jig
350
also comprises a multi-construction or multi-piece body having internal channel
353
0.081-0.083 inches in diameter and 0.187 inches deep for receiving anode
34
as shown. Distal end
352
of jig
350
includes rest
354
defined by the 0.016 inch slot 0.008 inches off the centerline between the two sections for receiving the distal end of probe
78
as shown. The body of trigger probe jig
350
has a circumference (0.190-0.194 inches in diameter) and a length (0.237 inches) sized to correctly orient the tip of trigger probe
78
with respect to arc gap
28
between cathode
58
and anode
34
.
The overall result is a high output, long life arc discharge lamp designed to be operated in a pulsed mode. The vertically disposed electrodes and integrated optical components provide an arc discharge lamp with improved lambertian distribution, and increased stability. The arc discharge lamp of this invention requires less power to operate for a given output, lasts longer, and does not suffer from excess sputtering or breakdown potentials. Typically, the arc discharge lamp is single ended: that is, all the electrodes extend from the base portion of the lamp. The arc discharge lamp of this invention is relatively easy and inexpensive to manufacture and can be repeatedly assembled in an exacting configuration. Cathode jig
300
,
FIGS. 23-26
co-axially aligns and correctly distances the arc discharge lamp cathode
58
with respect to the anode
34
. Trigger probe jig
350
,
FIGS. 27-29
correctly orients the trigger probe
78
tip with respect to the arc gap
28
.
In this invention, the advantages of vertically disposed anode
34
and cathode
58
,
FIG. 1
are realized in a pulsed mode arc discharge lamp
10
by a uniquely configured anode, cathode, and trigger probe, a monolithically constructed base and side wall
14
, an integral reflector
16
constructed directly on the ceramic housing, the use of the novel cathode jig which assists manufacturing personnel in co-axially aligning and precisely distancing cathode
58
with respect to anode
34
, and the novel trigger probe jig which assists manufacturing personnel in precisely orienting the tip of probe
78
with respect to arc gap
28
.
FIG. 30
shows lamp
10
featuring sparker assembly
400
with conductor
406
which extends to and within gas fill tube
500
terminating in spring bend
502
. In this way, once exhaust tube
500
is tipped off, it serves as the sparker lead.
Although specific features of the invention are shown in some drawings and not in others, this is for convenience only as each feature may be combined with any or all of the other features in accordance with the invention. The words “including”, “comprising”, “having”, and “with” as used herein are to be interpreted broadly and comprehensively and are not limited to any physical interconnection. Moreover, any embodiments disclosed in the subject application are not to be taken as the only possible embodiments.
Other embodiments will occur to those skilled in the art and are within the following claims:
Claims
- 1. A probe stabilized arc discharge lamp comprising:a monolithic base portion and side wall portion defining a concave surface; a window spaced from the base portion and sealed with respect to the side wall portion defining a chamber; a gas in the chamber; a reflector disposed on or integral with the concave surface, the reflector having a focal point; a first electrode centrally disposed in the base portion and having a distal end which extends outwardly from the base portion, the first electrode including an anode support and an anode vertically supported by the anode support; a second electrode also having a distal end which extends outwardly from the base portion, the second electrode including a cathode support extending vertically upward through the side wall portion, a cathode support arm extending horizontally inward from the cathode support, and a cathode extending vertically downward from the cathode support arm to a location spaced from the anode to define an arc gap at the focal point of the reflector; and a third electrode also having a distal end which extends outwardly from the base portion, the third electrode extending vertically upward through the side wall portion and having a reduced circumference region proximate the side wall portion, the third electrode further including a trigger probe extending from the reduced circumference region to or proximate to the arc gap for triggering an arc in the arc gap between the anode and the electrode.
- 2. The lamp of claim 1 in which the base portion and the side wall portion are made of a ceramic material.
- 3. The lamp of claim 1 in which the anode is made of tungsten.
- 4. The lamp of claim 1 in which the anode support includes a distal seat for receiving the anode.
- 5. The lamp of claim 1 in which the anode support is made of Kovar.
- 6. The lamp of claim 1 in which the anode has a flat distal surface with no chamfers.
- 7. The lamp of claim 1 in which the cathode support is made of Kovar.
- 8. The lamp of claim 1 in which the cathode support arm is made of molybdenum.
- 9. The lamp of claim 1 in which the cathode is made of a material including tungsten.
- 10. The lamp of claim 9 in which the cathode is made of 80% dense tungsten impregnated with barium, calcium, and aluminate.
- 11. The lamp of claim 1 in which the cathode has a tapered distal end.
- 12. The lamp of claim 11 in which the cathode has a pointed and tapered distal end.
- 13. The lamp of claim 12 in which the taper is approximately 60°.
- 14. The lamp of claim 1 in which the cathode support has a recess on a distal end thereof for receiving one end of the cathode support arm and the cathode has a recess on a proximal end thereof for receiving the other end of the cathode support arm.
- 15. The lamp of claim 1 in which the third electrode includes a support extending upward through the side wall portion, a probe pin extending upward from the support, the probe pin having a reduced circumference, and a probe which extends from the probe pin.
- 16. The lamp of claim 15 in which the support includes seat therein for receiving the probe pin.
- 17. The lamp of claim 1 in which the window is made of sapphire.
- 18. The lamp of claim 1 in which the window is flat in shape.
- 19. The lamp of claim 1 in which the window is convex in shape.
- 20. The lamp of claim 1 in which the window includes a transparent member surrounded by a collar which is secured to the side wall portion.
- 21. The lamp of claim 20 further including a shield member extending about the collar and a portion of the side wall.
- 22. The lamp of claim 1 in which the side wall portion includes an integral support for the window.
- 23. The lamp of claim 1 in which the reflector is parabolic in shape.
- 24. The lamp of claim 1 in which the reflector is elliptical in shape.
- 25. The lamp of claim 1 in which the reflector terminates on the side wall portion at a location spaced from the cathode support.
- 26. The lamp of claim 1 in which the reflector terminates on the side wall portion at a location spaced from the reduced circumference region of the third electrode.
- 27. The lamp of claim 1 in which the trigger probe has a pointed distal tip.
- 28. The lamp of claim 1 in which the trigger probe has a distal tip offset from the arc gap.
- 29. The lamp of claim 1 further including a sparker assembly.
- 30. The lamp of claim 29 in which the sparker assembly includes a lead disposed in the chamber and an insulative support for the lead attached to the cathode support arm.
- 31. The lamp of claim 30 further including a gas fill tube, the sparker assembly further including an electrical conductor extending to and within the gas fill tube.
- 32. A probe stabilized arc discharge lamp comprising:a base portion and a side wall in monolithic construction defining a concave surface; a window spaced from the base portion, the side wall interconnecting the base portion with the window, the side wall, the base portion, and the window defining a gas in the chamber; a gas in the chamber; a first electrode disposed vertically in the chamber and extending outward through the base portion; a second electrode also disposed vertically in the chamber and spaced from and extending outward through the base portion, the second electrode spaced from the first electrode defining an arc gap between distal ends of the first and second electrodes, the concave surface surrounding the arc gap; a trigger probe extending to or proximate to the arc gap for triggering an arc in the arc gap; and a reflector disposed about the arc gap for directing radiation generated by the arc out the window.
- 33. The lamp of claim 32 in which the trigger probe has a tip offset from the arc gap.
- 34. The lamp of claim 32 in which the base portion and the side wall are made of ceramic material.
- 35. The lamp of claim 32 in which the reflector is a part of the concave surface.
- 36. The lamp of claim 32 in which the first electrode extends outwardly through the base portion and the second electrode also extends outwardly through the base portion.
- 37. The lamp of claim 32 in which the first electrode is centrally disposed in the base portion and terminates in an anode.
- 38. The lamp of claim 37 in which the anode is made of tungsten.
- 39. The lamp of claim 37 in which the first electrode includes an anode support for the anode.
- 40. The lamp of claim 39 in which the anode support includes a distal seat for receiving the anode.
- 41. The lamp of claim 39 in which the anode support is made of Kovar.
- 42. The lamp of claim 37 in which the anode has a flat distal surface with no chamfers.
- 43. The lamp of claim 32 in which the second electrode includes a cathode support extending up through the side wall, a cathode support arm extending horizontally from the cathode support inward over the arc gap, and a cathode extending vertically downward from the cathode support arm.
- 44. The lamp of claim 43 in which the cathode support is made of Kovar.
- 45. The lamp of claim 43 in which the cathode support arm in made of molybdenum.
- 46. The lamp of claim 43 in which the cathode is made of a material including tungsten.
- 47. The lamp of claim 46 in which the cathode is made of 80% dense tungsten impregnated with barium, calcium, and aluminate.
- 48. The lamp of claim 43 in which the cathode has a tapered distal end.
- 49. The lamp of claim 43 in which the cathode has a pointed distal end.
- 50. The lamp of claim 43 in which the cathode has a pointed and tapered distal end.
- 51. The lamp of claim 50 in which the taper is approximately 60°.
- 52. The lamp of claim 32 in which the trigger probe is disposed on one end on a probe support electrode which extends outwardly thought the base portion.
- 53. The lamp of claim 52 in which the probe support electrode includes a seat on a distal end thereof, the lamp further including a reduced circumference trigger probe support pin supported on one end by the seat in the probe support electrode, the trigger probe extending inwardly downward from the trigger probe support pin.
- 54. The lamp of claim 43 in which the cathode support has a recess on a distal end thereof for receiving one end of the cathode support arm and the cathode has a recess on a proximal end thereof for receiving the other end of the cathode support arm.
- 55. The lamp of claim 32 in which the trigger probe is disposed on one end on probe electrode which extends outwardly through the base portion.
- 56. The lamp of claim 55 in which the probe electrode includes an upper reduced area probe support pin having a distal end which supports the probe.
- 57. The lamp of claim 56 in which the probe electrode includes a distal probe support pin seat therein for receiving the probe support pins.
- 58. The lamp of claim 32 in which the window is made of sapphire.
- 59. The lamp of claim 32 in which the window is flat in shape.
- 60. The lamp of claim 32 in which the window is convex in shape.
- 61. The lamp of claim 32 in which the window includes a transparent member surrounded by collar which is secured to the side wall.
- 62. The lamp of claim 61 further including a shield member extending about the collar and a portion of the side wall.
- 63. The lamp of claim 32 in which the side wall includes an integral support for the window.
- 64. The lamp of claim 32 in which the reflector is parabolic in shape.
- 65. The lamp of claim 32 in which the reflector is elliptical in shape.
- 66. The lamp of claim 32 in which the reflector defines a focal point and the arc gap is disposed at the focal point of the reflector.
- 67. The lamp of claim 43 in which the reflector terminates on the side wall at a location spaced from the cathode support.
- 68. The lamp of claim 53 in which the reflector terminates on the side wall at a location spaced from the probe support pin.
- 69. The lamp of claim 32 in which the trigger probe has a pointed tip.
- 70. The lamp of claim 32 further including a sparker assembly.
- 71. The lamp of claim 70 in which the sparker assembly includes a lead disposed in the chamber and an insulative support for the lead.
- 72. The lamp of claim 71 further including a gas fill tube, the sparker assembly further including an electrical conductor extending to and within the gas fill tube.
- 73. A probe stabilized arc discharge lamp comprising:a base portion; a window spaced from the base portion; a side wall interconnecting the base portion with the window, the side wall, the base portion, and the window defining a gas in the chamber; a gas in the chamber; a first electrode disposed vertically in the chamber and extending outward through the base portion; a second electrode also disposed vertically in the chamber and spaced from and extending outward through the base portion, the second electrode spaced from the first electrode defining an arc gap between distal ends of the first and second electrodes the second electrode including a cathode support extending up through the side wall, a cathode support arm extending horizontally from the cathode support inward over the arc gap, and a cathode extending vertically downward from the cathode support arm; a trigger probe extending to or proximate to the arc gap for triggering an arc in the arc gap; and a reflector disposed about the arc gap for directing radiation generated by the arc out the window.
- 74. A probe stabilized arc discharge lamp comprising:a base portion; a window spaced from the base portion; a side wall interconnecting the base portion with the window, the side wall, the base portion, and the window defining a gas in the chamber; a gas m the chamber; a first electrode disposed vertically in the chamber and extending outward through the base portion; a second electrode also disposed vertically in the chamber and spaced from and extending outward through the base portion, the second electrode spaced from the first electrode defining an arc gap between distal ends of the first and second electrodes; a trigger probe extending to or proximate to the arc gap for triggering an arc in the arc gap, the trigger probe disposed on one end on a probe support electrode which extends outwardly thought the base portion, the probe support electrode including a seat on a distal end thereof, the lamp further including a reduced circumference trigger probe support pin supported on one end by the seat in the probe support electrode, the trigger probe extending inwardly downward from the trigger probe support pin; and a reflector disposed about the arc gap for directing radiation generated by the arc out the window.
- 75. A probe stabilized arc discharge lamp comprising:a base portion and a side wall in monolithic construction defining a concave surface; a window spaced from the base portion, the window, the base portion, and the side wall defining a chamber; a gas in the chamber; a first electrode disposed vertically in the chamber; a second electrode also disposed vertically in the chamber and spaced from the first electrode defining an arc gap between the distal ends of the first and second electrodes; a trigger probe extending to or proximate to the arc gap for triggering an arc in the arc gap; and a reflector disposed on the concave surface and about the arc gap for directing radiation generated by the arc out the window.
- 76. A probe stabilized arc discharge lamp comprising:a monolithic base portion and side wall portion defining a concave surface; a window spaced from the base portion and sealed with respect to the side wall portion defining a chamber; a gas in the chamber; a reflector disposed on or integral with the concave surface, the reflector having a focal point; an anode support extending through the base portion and an anode vertically supported by the anode support; a cathode support vertically extending up through the side wall portion, a cathode support arm extending horizontally inward from the cathode support, and a cathode extending vertically downward from the cathode support arm to a location spaced from the anode to define an arc gap at the focal point of the reflector; a trigger probe support extending vertically upward through the side wall portion and having a reduced circumference region proximate the side wall portion, and a trigger probe extending inwardly and downward from the reduced circumference region to or proximate to the arc gap for triggering an arc in the arc gap between the anode and the electrode; and a sparker assembly with a lead disposed in the chamber.
- 77. A probe stabilized arc discharge lamp comprising:a base portion; a window spaced from the base portion; a side wall interconnecting the base portion with the window, the side wall, the base portion, and the window defining a gas in the chamber; a gas in the chamber, a first electrode disposed vertically in the chamber and extending outward through the base portion, the first electrode centrally disposed in the base portion and terminating in an anode; a second electrode also disposed vertically in the chamber and spaced from and extending outward through the base portion, the second electrode spaced from the first electrode defining an arc gap between distal ends of the first and second electrodes; a trigger probe extending to or proximate to the arc gap for triggering an arc in the arc gap; and a reflector disposed about the arc gap for directing radiation generated by the arc out the window.
- 78. The lamp of claim 77 in which the anode is made of tungsten.
- 79. The lamp of claim 77 in which the first electrode includes an anode support for the anode.
- 80. The lamp of claim 79 in which the anode support includes a distal seat for receiving the anode.
- 81. The lamp of claim 79 in which the anode support is made of Kovar.
- 82. The lamp of claim 77 in which the anode has a flat distal surface with no chamfers.
US Referenced Citations (14)