CA1155905A - Low pressure gas discharge lamp with increased end illumination - Google Patents
Low pressure gas discharge lamp with increased end illuminationInfo
- Publication number
- CA1155905A CA1155905A CA000376481A CA376481A CA1155905A CA 1155905 A CA1155905 A CA 1155905A CA 000376481 A CA000376481 A CA 000376481A CA 376481 A CA376481 A CA 376481A CA 1155905 A CA1155905 A CA 1155905A
- Authority
- CA
- Canada
- Prior art keywords
- pair
- lamp
- electrodes
- envelope
- electrode pair
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
- 238000005286 illumination Methods 0.000 title claims abstract description 25
- 238000010891 electric arc Methods 0.000 claims description 10
- 239000000463 material Substances 0.000 claims description 10
- 238000002955 isolation Methods 0.000 claims description 4
- 239000011521 glass Substances 0.000 claims description 2
- 238000010438 heat treatment Methods 0.000 claims description 2
- 230000000977 initiatory effect Effects 0.000 claims description 2
- 238000004804 winding Methods 0.000 claims description 2
- 238000007789 sealing Methods 0.000 claims 1
- QSHDDOUJBYECFT-UHFFFAOYSA-N mercury Chemical compound [Hg] QSHDDOUJBYECFT-UHFFFAOYSA-N 0.000 abstract description 7
- 229910052753 mercury Inorganic materials 0.000 abstract description 7
- 238000010276 construction Methods 0.000 abstract description 4
- 229910052721 tungsten Inorganic materials 0.000 description 3
- 239000010937 tungsten Substances 0.000 description 3
- 241000510032 Ellipsaria lineolata Species 0.000 description 2
- 238000000576 coating method Methods 0.000 description 2
- 238000000034 method Methods 0.000 description 2
- 239000004065 semiconductor Substances 0.000 description 2
- WFKWXMTUELFFGS-UHFFFAOYSA-N tungsten Chemical compound [W] WFKWXMTUELFFGS-UHFFFAOYSA-N 0.000 description 2
- OAICVXFJPJFONN-UHFFFAOYSA-N Phosphorus Chemical compound [P] OAICVXFJPJFONN-UHFFFAOYSA-N 0.000 description 1
- 229910052788 barium Inorganic materials 0.000 description 1
- DSAJWYNOEDNPEQ-UHFFFAOYSA-N barium atom Chemical compound [Ba] DSAJWYNOEDNPEQ-UHFFFAOYSA-N 0.000 description 1
- 230000002146 bilateral effect Effects 0.000 description 1
- 239000011248 coating agent Substances 0.000 description 1
- 230000009977 dual effect Effects 0.000 description 1
- 150000002500 ions Chemical class 0.000 description 1
- 230000003287 optical effect Effects 0.000 description 1
- 238000007493 shaping process Methods 0.000 description 1
- 238000001228 spectrum Methods 0.000 description 1
- 229910052712 strontium Inorganic materials 0.000 description 1
- CIOAGBVUUVVLOB-UHFFFAOYSA-N strontium atom Chemical compound [Sr] CIOAGBVUUVVLOB-UHFFFAOYSA-N 0.000 description 1
- 238000009827 uniform distribution Methods 0.000 description 1
Classifications
-
- H—ELECTRICITY
- H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
- H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
- H05B41/00—Circuit arrangements or apparatus for igniting or operating discharge lamps
- H05B41/14—Circuit arrangements
- H05B41/16—Circuit arrangements in which the lamp is fed by dc or by low-frequency ac, e.g. by 50 cycles/sec ac, or with network frequencies
- H05B41/20—Circuit arrangements in which the lamp is fed by dc or by low-frequency ac, e.g. by 50 cycles/sec ac, or with network frequencies having no starting switch
- H05B41/23—Circuit arrangements in which the lamp is fed by dc or by low-frequency ac, e.g. by 50 cycles/sec ac, or with network frequencies having no starting switch for lamps not having an auxiliary starting electrode
- H05B41/232—Circuit arrangements in which the lamp is fed by dc or by low-frequency ac, e.g. by 50 cycles/sec ac, or with network frequencies having no starting switch for lamps not having an auxiliary starting electrode for low-pressure lamps
- H05B41/2325—Circuit arrangements in which the lamp is fed by dc or by low-frequency ac, e.g. by 50 cycles/sec ac, or with network frequencies having no starting switch for lamps not having an auxiliary starting electrode for low-pressure lamps provided with pre-heating electrodes
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
- H01J61/00—Gas-discharge or vapour-discharge lamps
- H01J61/92—Lamps with more than one main discharge path
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
- Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10S315/00—Electric lamp and discharge devices: systems
- Y10S315/01—Fluorescent lamp circuits with more than two principle electrodes
Abstract
ABSTRACT
A low pressure gas discharge lamp is provided with a pair of high power incandescent electrodes to in-crease output illumination at the lamp ends. In an alternate construction, the electrodes are of high power, low emissivity and are electrically connected to a second pair of high emissivity electrodes which provide the means for enabling the mercury discharge. With this second construction, the low emissivity electrodes can act as ballast for the circuit.
A low pressure gas discharge lamp is provided with a pair of high power incandescent electrodes to in-crease output illumination at the lamp ends. In an alternate construction, the electrodes are of high power, low emissivity and are electrically connected to a second pair of high emissivity electrodes which provide the means for enabling the mercury discharge. With this second construction, the low emissivity electrodes can act as ballast for the circuit.
Description
1 ~5~5 LOW PRESSURE G~S DISCHARGE L~P
BACKGRO~ND OF THE INVEN~ION
This invention relates to low pressure gas discharge lamps and, particularly, to an apertured fluorescent lamp of the type used to provide a uniform distribution of illumination along a surface~
Tubular low pressure arc discharge lamps, such as conventional fluorescent and sodîum vapor lamps, project light upon a surface in a relatively uniform manner except for a gradual decrease in illumination near the ends. This end~falloff is ordinarily not a prohlem when the lamp is used for general purpose lighting. In certain applications, howevex, such as use as the exposure source in a photocopying machine, the light falloff must be compensated for in some manner since relatively uniform illumination of the entire width of a document to be copied must be obtained. Various ways of providing for this compensation are known to the art:
U.S. Patents 3,225,241 and 3,717,781 are representative of the so-called aperture fluorescent lamps which disclose ways of charging the properties of the coatings near the ends of the lamp. In the xerographic art, it is more usual to shape the output light profile of the scanning lamp by interposing a so-called butterfly slit between the lamp and the document, the slit shape serving to allow increased illumination at the j ~ ends of the document~ Alternatively, the longitudinal dimensions of the lamp are increased so that only the central portion of the lamp which provides relatively uniform illumination is utilized.
It is an object of an aspect of this invention to provide an apertured gas discharge lamp which provides relatively uniform illumination along the entire length of ; the aperture.
.. :
- .
, :
.
, .. . ..
~ ~5~9~5 It is an object of an aspect of the invention to provide an aperture lamp of reduced length which nonetheless provides uniform illumination along the length of the aperture.
According to an aspect of the present invention, an apertured low pressure gas discharge lamp utilizes end fila-ments which are of relatively high pow~r and of high color temperature. These filaments contribute to the light output at the tube ends which compensates for the illumination fall-o~f.
Other aspects of the invention are as follows:
A low pressure arc discharge lamp having internal ballasting comprising: an elongated light transmissive envelope containing an ioni~able medium therein, a source of AC line voltage, a first pair of electrodes sealed into the opposite ends of said envelope and electrical]y connect~
ed to said voltage source, said electrodes constructed of - a ma~erial having high power and low emissivity, a second pair of electrodes sealed into the opposite ends of said tu~e and electrically connected to said voltage source, said second electrode pair constructed of a material having high emissivity and means for electrically isolating said first and second electrode pairs~ wherein upon application of said line voltage an ionization discharge o~ said medium occurs with said first electode pair providing the necessary impedance to limit lamp operating current while simul~aneously providing additional illumination to compen-sate for illumination falloff at the ends of the lamp.
A low pressure arc discharge lamp comprising: an elongated light transmissive envelope containing an ionizable medium thereinl a first pair of electrodes sealed into the opposite ends of said envelope, said electrodes constructed of a material having high power and low emissivity, and .~, ' ', .
~ ~ 55~5 -2a-~ second pair of electrodes sealed into said opposite ends of said envelope and electrically isolated from said first electrode pair, said second pair of electrodes having high emissivity characteristics.
A self-ballasting low pressure arc discharge lamp comprising: an elongated light transmissive envelope con-taining an inonizable medium therein, a source of AC line voltage, a first pair of high power low emissivity electrodes sealed into the opposite ends of said envelope, a second pair of high emissivity lectrodes located in close proximity to said first electrode pair and connected to said AC line voltage, a transformer connected between said AC line source and said lamp electrodes, the secondary winding of said transformer connected to said first electrode pair, gating means for applying a preheat voltage to said first electrode pair and for initiating ionization of said medium, said first electrode pair, during arc dischargeS forming, with said transformer, part of the system ballasting, while simultaneously heating said second electrode pair to a high-er brightness level.
DRAWINGS
.
Figure 1 shows a prior art fluorescent lamp with anon-uniform irradiance proEile at a document plane.
Figure 2 shows a fluorescent lamp utilizing high power filaments, the power being supplied by an isolation transformer.
Figure 3 is a plot of tube length vs. document plane irradiance for the lamp shown in Figure 2.
Figure 4a shows a fluorescent lamp with a first alternate electrode construction utilizing pairs of auxi-liary high emissivity electrodes.
Figure 4b is a circuit utilizing the lamp shown in Figure 4a.
~ .
~ :l 5 5 ~
-2b-Figure 5a shows a fluorescent lamp with a second electrode construction utilizing pairs of auxiliary high emissivity electrodes.
Figure 5b is a circuit utilizing the lamp shown in Figure 5a.
DESCRIPTION
Although the inventive features of the present invention are applicable to any low pressure gas discharge lamp, the following description is related to fluorescent-type lamps. Commercial fluorescent lamps are basicallylow pressure mercury discharge lamps designed to emit a maximum portion of their energy in the 2537 A
~55~
line of the mercury spectrum. This short wave ultra-violet energy is converted by the phosphor coating the insides of the tubes into visible light. Figure 1 shows a prior art fluorescent lamp with its typical document irradiance profile. As shown, larnp 2 has high emissivity incandescent filaments 3,4, i.e. the filaments have a high abili~y to emit or give off electrons~ The oxide coated filaments typically are of low power (approxi-mately 4 watts) which are heated to a low color tempera-ture of approximately 1350K before arc discharge. Whenenergized, the lamp provides a document illumination out~
put profile 5 at a plane D parallel ~o the axis of the lamp. The profile is fairly uniform over a central por-tion A but falls off over end portions B and C due to the finite length of the arc. If uniform illumination of a surface is required, as ~or example, in the illumination of a document to be copied in a photocopying application, several limited options have heretofore been available.
In one solution only the central portion A of the lamp output is used in an apertured configuration extending the length of the lamp until portion A is long enough to illuminate the required surface length. Another solution is to compensate for the light falloff by shaping the lamp aperture to allow more light to be emitted from the endsO Still another method is to attenuate the central portions of the illumination profile by use of a "butter-fly" slit in the optical path of the photocopies. This solution requires added lamp power to maintain sufficient exposure.
According to the principles of the present in-vention, the filaments 3,4 are energized to a color tem-perature and power level sufficiently high to contribute an additional component of light which compensates for the illumination falloff at end portions B and C.
3s Figure 2 shows a circuit wherein tungsten ila--ments 12,13 of lamp 14 are operated at approximately 3000K.
., 5.~9~5 Transformer 16 connected to a power source (not shown) supplies an isolated current to filaments 12 and 13. The lamp is operated from ac source 18 which sup-plies curren~ sufficient to cause a discharge between filaments 12rl3. Ballast 20 is a positive impedance de-vice connected between the lamp and source 18 to provide the required current limiting. As one example of pos-sible operating parameters, transformer 16 provides 40 watts each to filaments 12,13 causing them to incandesce to a color temperature of approximately 3000K. Figure 3 demonstrates the compensation to one end oE the tube re-sulting from the increased light contribution of the end ilament. Portion B' represents the inherent illumina-tion falloff at the lamp's end; portion F represents the contribution to light output by the high brightness fila-ment 12 and portion R represents the increase in illu~
mination level. It is, of course, understood that other operating parameters are possible consistent with the principles of the invention; i.e. so long as increased light output of the filaments is achieved.
Figures 4 and 5 provide alternate configura-tions of the invention wherein one set of filaments of high power and low emissivity provide increased end illu-mination. The second set of filaments are constructed of high emissivity electrodes and are incorporated within the lamp to facilitate normal mercury discharge. The high power, low emissivity filaments, according to another fea~ure of the present invention, can be utilized as the ballast for the circuitO
Referring now to Figures 4A, 4B, lamp 30 has a pair of high power, low emissivity filaments 3~, 34 and high emissivity filaments 36,380 Transformers 40,42 con-nected to a power source (not shown) supply a preheat voltage to filaments 36, 38. Upon the closing of switch 46, power is applied to the lamp electrodes. In opera-tion, filaments 36, 38 in lamp 30 act in the manner of a '"` ~ 15'j9~5 standard fluorescent lamp, while filaments 32, 34 provide the additional light necessary to compensate for the end falloff of the aerial illumination profile. Filaments 32, 34 can also ballast the fluorescent portion of lamp 30, if the filaments are electrically isolated from fila-ments 36, 38 and from the mercury arc discharge. This can be accomplished using known transformer isolation techniques. Alternatively, filaments 32, 34 can also be isolated by mounting each filament within a glass en-10 velope. `!
Typical operating parameters for this embodi-ment areo Line voltage ~ 120/240 ac Transformers 40,42 - standard filament trans-formers with dual isolated outputs at 3.8 VAC, lo 1 ampseach E'ilaments 36, 38 color temperature -1350~K
Filaments 32, 34 color temperature - 3000K
20Filaments 32, 34 material - tungsten Filaments 36, 38 material - oxide coated tung-sten (barium, strontium are suitable materials) Referring now to Figures~ 5A, 5B, lamp 50 has a pair of high power~ low emissivity filaments 52,54 and a pair of high emissivity electrodes 56,58. Filaments 52,54 are constructed of a low emission material which does not release electrons as effectively as elestrodes 56,58 which are constructed of high emission materials.
Heat produced by filaments 52,54 indirectly heats elec-trodes 56 and 58, respectively, causing them to become effective emitters. Transformer 59 provides electrical isolation for filaments 52, 54.
Triacs 60,62 are bilaterial semiconductor switches which, when gated, permit current conduction in the direction indicated by the forward bias of the semiconductor. ~s will be understood, other types of , ~
, ,, 5 ~ ~ ~
bilateral switching currents may be used in place of triacs 60,62. In operation, and with discharge lamp 50 being off, a voltage is applied to gate 60a and 62a causing switch 60 and ~ to conduct and apply an initial preheat voltage to filaments 56~58 causing the filaments to heat up.
When electrodes 56,58 are sufficiently heated to approximately 1350K, triac 62 is turned off, causing a sufficient voltage drop across electrodes 56 and 58 to initiate a mercury discharge. Once started, the arc discharge is "self-sustaining". Since filaments 52 and 54 emit few electrons, they provide a portion of the necessary ballast by contributing their resistance to the primary of transformer 59 which is in series with the main discharge path of the mercury arc.
With all of the above embodiments, i~ is ob-vious that the end portion of the lamp segments B and C of Figure l can be made to produce illumination which is uniform wi~h the central (A) portion of the lamp. It is thus not necessary to lengthen the tube length to achieve the required illumination uniformity thus permitting a moxe compact illumination system t:o be used.
. ~ . , ' - ~ .
,
BACKGRO~ND OF THE INVEN~ION
This invention relates to low pressure gas discharge lamps and, particularly, to an apertured fluorescent lamp of the type used to provide a uniform distribution of illumination along a surface~
Tubular low pressure arc discharge lamps, such as conventional fluorescent and sodîum vapor lamps, project light upon a surface in a relatively uniform manner except for a gradual decrease in illumination near the ends. This end~falloff is ordinarily not a prohlem when the lamp is used for general purpose lighting. In certain applications, howevex, such as use as the exposure source in a photocopying machine, the light falloff must be compensated for in some manner since relatively uniform illumination of the entire width of a document to be copied must be obtained. Various ways of providing for this compensation are known to the art:
U.S. Patents 3,225,241 and 3,717,781 are representative of the so-called aperture fluorescent lamps which disclose ways of charging the properties of the coatings near the ends of the lamp. In the xerographic art, it is more usual to shape the output light profile of the scanning lamp by interposing a so-called butterfly slit between the lamp and the document, the slit shape serving to allow increased illumination at the j ~ ends of the document~ Alternatively, the longitudinal dimensions of the lamp are increased so that only the central portion of the lamp which provides relatively uniform illumination is utilized.
It is an object of an aspect of this invention to provide an apertured gas discharge lamp which provides relatively uniform illumination along the entire length of ; the aperture.
.. :
- .
, :
.
, .. . ..
~ ~5~9~5 It is an object of an aspect of the invention to provide an aperture lamp of reduced length which nonetheless provides uniform illumination along the length of the aperture.
According to an aspect of the present invention, an apertured low pressure gas discharge lamp utilizes end fila-ments which are of relatively high pow~r and of high color temperature. These filaments contribute to the light output at the tube ends which compensates for the illumination fall-o~f.
Other aspects of the invention are as follows:
A low pressure arc discharge lamp having internal ballasting comprising: an elongated light transmissive envelope containing an ioni~able medium therein, a source of AC line voltage, a first pair of electrodes sealed into the opposite ends of said envelope and electrical]y connect~
ed to said voltage source, said electrodes constructed of - a ma~erial having high power and low emissivity, a second pair of electrodes sealed into the opposite ends of said tu~e and electrically connected to said voltage source, said second electrode pair constructed of a material having high emissivity and means for electrically isolating said first and second electrode pairs~ wherein upon application of said line voltage an ionization discharge o~ said medium occurs with said first electode pair providing the necessary impedance to limit lamp operating current while simul~aneously providing additional illumination to compen-sate for illumination falloff at the ends of the lamp.
A low pressure arc discharge lamp comprising: an elongated light transmissive envelope containing an ionizable medium thereinl a first pair of electrodes sealed into the opposite ends of said envelope, said electrodes constructed of a material having high power and low emissivity, and .~, ' ', .
~ ~ 55~5 -2a-~ second pair of electrodes sealed into said opposite ends of said envelope and electrically isolated from said first electrode pair, said second pair of electrodes having high emissivity characteristics.
A self-ballasting low pressure arc discharge lamp comprising: an elongated light transmissive envelope con-taining an inonizable medium therein, a source of AC line voltage, a first pair of high power low emissivity electrodes sealed into the opposite ends of said envelope, a second pair of high emissivity lectrodes located in close proximity to said first electrode pair and connected to said AC line voltage, a transformer connected between said AC line source and said lamp electrodes, the secondary winding of said transformer connected to said first electrode pair, gating means for applying a preheat voltage to said first electrode pair and for initiating ionization of said medium, said first electrode pair, during arc dischargeS forming, with said transformer, part of the system ballasting, while simultaneously heating said second electrode pair to a high-er brightness level.
DRAWINGS
.
Figure 1 shows a prior art fluorescent lamp with anon-uniform irradiance proEile at a document plane.
Figure 2 shows a fluorescent lamp utilizing high power filaments, the power being supplied by an isolation transformer.
Figure 3 is a plot of tube length vs. document plane irradiance for the lamp shown in Figure 2.
Figure 4a shows a fluorescent lamp with a first alternate electrode construction utilizing pairs of auxi-liary high emissivity electrodes.
Figure 4b is a circuit utilizing the lamp shown in Figure 4a.
~ .
~ :l 5 5 ~
-2b-Figure 5a shows a fluorescent lamp with a second electrode construction utilizing pairs of auxiliary high emissivity electrodes.
Figure 5b is a circuit utilizing the lamp shown in Figure 5a.
DESCRIPTION
Although the inventive features of the present invention are applicable to any low pressure gas discharge lamp, the following description is related to fluorescent-type lamps. Commercial fluorescent lamps are basicallylow pressure mercury discharge lamps designed to emit a maximum portion of their energy in the 2537 A
~55~
line of the mercury spectrum. This short wave ultra-violet energy is converted by the phosphor coating the insides of the tubes into visible light. Figure 1 shows a prior art fluorescent lamp with its typical document irradiance profile. As shown, larnp 2 has high emissivity incandescent filaments 3,4, i.e. the filaments have a high abili~y to emit or give off electrons~ The oxide coated filaments typically are of low power (approxi-mately 4 watts) which are heated to a low color tempera-ture of approximately 1350K before arc discharge. Whenenergized, the lamp provides a document illumination out~
put profile 5 at a plane D parallel ~o the axis of the lamp. The profile is fairly uniform over a central por-tion A but falls off over end portions B and C due to the finite length of the arc. If uniform illumination of a surface is required, as ~or example, in the illumination of a document to be copied in a photocopying application, several limited options have heretofore been available.
In one solution only the central portion A of the lamp output is used in an apertured configuration extending the length of the lamp until portion A is long enough to illuminate the required surface length. Another solution is to compensate for the light falloff by shaping the lamp aperture to allow more light to be emitted from the endsO Still another method is to attenuate the central portions of the illumination profile by use of a "butter-fly" slit in the optical path of the photocopies. This solution requires added lamp power to maintain sufficient exposure.
According to the principles of the present in-vention, the filaments 3,4 are energized to a color tem-perature and power level sufficiently high to contribute an additional component of light which compensates for the illumination falloff at end portions B and C.
3s Figure 2 shows a circuit wherein tungsten ila--ments 12,13 of lamp 14 are operated at approximately 3000K.
., 5.~9~5 Transformer 16 connected to a power source (not shown) supplies an isolated current to filaments 12 and 13. The lamp is operated from ac source 18 which sup-plies curren~ sufficient to cause a discharge between filaments 12rl3. Ballast 20 is a positive impedance de-vice connected between the lamp and source 18 to provide the required current limiting. As one example of pos-sible operating parameters, transformer 16 provides 40 watts each to filaments 12,13 causing them to incandesce to a color temperature of approximately 3000K. Figure 3 demonstrates the compensation to one end oE the tube re-sulting from the increased light contribution of the end ilament. Portion B' represents the inherent illumina-tion falloff at the lamp's end; portion F represents the contribution to light output by the high brightness fila-ment 12 and portion R represents the increase in illu~
mination level. It is, of course, understood that other operating parameters are possible consistent with the principles of the invention; i.e. so long as increased light output of the filaments is achieved.
Figures 4 and 5 provide alternate configura-tions of the invention wherein one set of filaments of high power and low emissivity provide increased end illu-mination. The second set of filaments are constructed of high emissivity electrodes and are incorporated within the lamp to facilitate normal mercury discharge. The high power, low emissivity filaments, according to another fea~ure of the present invention, can be utilized as the ballast for the circuitO
Referring now to Figures 4A, 4B, lamp 30 has a pair of high power, low emissivity filaments 3~, 34 and high emissivity filaments 36,380 Transformers 40,42 con-nected to a power source (not shown) supply a preheat voltage to filaments 36, 38. Upon the closing of switch 46, power is applied to the lamp electrodes. In opera-tion, filaments 36, 38 in lamp 30 act in the manner of a '"` ~ 15'j9~5 standard fluorescent lamp, while filaments 32, 34 provide the additional light necessary to compensate for the end falloff of the aerial illumination profile. Filaments 32, 34 can also ballast the fluorescent portion of lamp 30, if the filaments are electrically isolated from fila-ments 36, 38 and from the mercury arc discharge. This can be accomplished using known transformer isolation techniques. Alternatively, filaments 32, 34 can also be isolated by mounting each filament within a glass en-10 velope. `!
Typical operating parameters for this embodi-ment areo Line voltage ~ 120/240 ac Transformers 40,42 - standard filament trans-formers with dual isolated outputs at 3.8 VAC, lo 1 ampseach E'ilaments 36, 38 color temperature -1350~K
Filaments 32, 34 color temperature - 3000K
20Filaments 32, 34 material - tungsten Filaments 36, 38 material - oxide coated tung-sten (barium, strontium are suitable materials) Referring now to Figures~ 5A, 5B, lamp 50 has a pair of high power~ low emissivity filaments 52,54 and a pair of high emissivity electrodes 56,58. Filaments 52,54 are constructed of a low emission material which does not release electrons as effectively as elestrodes 56,58 which are constructed of high emission materials.
Heat produced by filaments 52,54 indirectly heats elec-trodes 56 and 58, respectively, causing them to become effective emitters. Transformer 59 provides electrical isolation for filaments 52, 54.
Triacs 60,62 are bilaterial semiconductor switches which, when gated, permit current conduction in the direction indicated by the forward bias of the semiconductor. ~s will be understood, other types of , ~
, ,, 5 ~ ~ ~
bilateral switching currents may be used in place of triacs 60,62. In operation, and with discharge lamp 50 being off, a voltage is applied to gate 60a and 62a causing switch 60 and ~ to conduct and apply an initial preheat voltage to filaments 56~58 causing the filaments to heat up.
When electrodes 56,58 are sufficiently heated to approximately 1350K, triac 62 is turned off, causing a sufficient voltage drop across electrodes 56 and 58 to initiate a mercury discharge. Once started, the arc discharge is "self-sustaining". Since filaments 52 and 54 emit few electrons, they provide a portion of the necessary ballast by contributing their resistance to the primary of transformer 59 which is in series with the main discharge path of the mercury arc.
With all of the above embodiments, i~ is ob-vious that the end portion of the lamp segments B and C of Figure l can be made to produce illumination which is uniform wi~h the central (A) portion of the lamp. It is thus not necessary to lengthen the tube length to achieve the required illumination uniformity thus permitting a moxe compact illumination system t:o be used.
. ~ . , ' - ~ .
,
Claims (4)
1. A low pressure arc discharge lamp having internal ballasting comprising: an elongated light transmissive envelope containing an ionizable medium therein, a source of AC line voltage, a first pair of electrodes sealed into the opposite ends of said envelope and electrically connect-ed to said voltage source, said electrodes constructed of a material having high power and low emissivity, a second pair of electrodes sealed into the opposite ends of said tube and electrically connected to said voltage source, said second electrode pair constructed of a material having high emissivity and means for electrically isolating said first and second electrode pairs, wherein upon application of said line voltage an ionization discharge of said medium occurs with said first electode pair providing the necessary impedance to limit lamp operating current while simultaneously providing additional illumination to compen-sate for illumination falloff at the ends of the lamp.
2. The lamp as claimed in claim 1 wherein said isola-tion means comprises a glass envelope surrounding and seal-ing said first electrode pair.
3. A low pressure arc discharge lamp comprising: an elongated light transmissive envelope containing an ionizable medium therein, a first pair of electrodes sealed into the opposite ends of said envelope, said electrodes constructed of a material having high power and low emissivity, and a second pair of electrodes sealed into said opposite ends of said envelope and electrically isolated from said first electrode pair, said second pair of eletrodes having high emissivity characteristics.
4. A self-ballasting low pressure arc discharge lamp comprising: an elongated light transmissive envelope con-taining an ionizable medium therein, a source of AC line voltage, a first pair of high power low emissivity electrodes sealed into the opposite ends of said envelope, a second pair of high emissivity electrodes located in close proximity to said first electrode pair and connected to said AC line voltage, a transformer connected between said AC line source and said lamp electrodes, the secondary winding of said transformer connected to said first electrode pair, gating means for applying a preheat voltage to said first electrode pair and for initiating ionization of said medium, said first electrode pair, during arc dischage, forming, with said transformer, part of the system ballasting, while simul-taneously heating said second electrode pair to a higher brightness level.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US151,012 | 1980-05-19 | ||
| US06/151,012 US4329622A (en) | 1980-05-19 | 1980-05-19 | Low pressure gas discharge lamp with increased end illumination |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1155905A true CA1155905A (en) | 1983-10-25 |
Family
ID=22536960
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000376481A Expired CA1155905A (en) | 1980-05-19 | 1981-04-29 | Low pressure gas discharge lamp with increased end illumination |
Country Status (5)
| Country | Link |
|---|---|
| US (1) | US4329622A (en) |
| EP (1) | EP0040547B1 (en) |
| JP (1) | JPS5711465A (en) |
| CA (1) | CA1155905A (en) |
| DE (1) | DE3172489D1 (en) |
Families Citing this family (56)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4442374A (en) * | 1982-03-25 | 1984-04-10 | Gte Products Corporation | Dual length copier lamp |
| JPS603644U (en) * | 1983-06-22 | 1985-01-11 | 日本無線株式会社 | Fluorescent lamp for document illumination |
| WO1989002160A1 (en) * | 1987-08-25 | 1989-03-09 | Mitsubishi Denki Kabushiki Kaisha | Hot cathode type low pressure rare gas discharge lamp |
| US4902933A (en) * | 1988-09-20 | 1990-02-20 | General Electric Company | High efficacy discharge lamp having large anodes |
| US5107183A (en) * | 1989-10-16 | 1992-04-21 | Minipilo Electric Co., Ltd. | Discharging method and small fluorescent lamp using the discharging method |
| US5066892A (en) * | 1990-12-07 | 1991-11-19 | Gte Products Corporation | Glow discharge lamp with incandescent filament |
| US5610477A (en) * | 1994-04-26 | 1997-03-11 | Mra Technology Group | Low breakdown voltage gas discharge device and methods of manufacture and operation |
| DE9417965U1 (en) * | 1994-11-10 | 1995-01-19 | Sotralentz Sa | Pallet container |
| US5989462A (en) | 1997-07-31 | 1999-11-23 | Q2100, Inc. | Method and composition for producing ultraviolent blocking lenses |
| SE520653C2 (en) * | 1998-02-18 | 2003-08-05 | Pls Systems I Hestra Ab | Device for use in the operation of one or more discharge lamps |
| US6478990B1 (en) * | 1998-09-25 | 2002-11-12 | Q2100, Inc. | Plastic lens systems and methods |
| US6419873B1 (en) | 1999-03-19 | 2002-07-16 | Q2100, Inc. | Plastic lens systems, compositions, and methods |
| US6191539B1 (en) | 1999-03-26 | 2001-02-20 | Korry Electronics Co | Fluorescent lamp with integral conductive traces for extending low-end luminance and heating the lamp tube |
| US6528955B1 (en) * | 2000-03-30 | 2003-03-04 | Q2100, Inc. | Ballast system for a fluorescent lamp |
| US6698708B1 (en) | 2000-03-30 | 2004-03-02 | Q2100, Inc. | Gasket and mold assembly for producing plastic lenses |
| US6960312B2 (en) | 2000-03-30 | 2005-11-01 | Q2100, Inc. | Methods for the production of plastic lenses |
| US6723260B1 (en) | 2000-03-30 | 2004-04-20 | Q2100, Inc. | Method for marking a plastic eyeglass lens using a mold assembly holder |
| US6716375B1 (en) | 2000-03-30 | 2004-04-06 | Q2100, Inc. | Apparatus and method for heating a polymerizable composition |
| US6632535B1 (en) | 2000-06-08 | 2003-10-14 | Q2100, Inc. | Method of forming antireflective coatings |
| US7060208B2 (en) | 2001-02-20 | 2006-06-13 | Q2100, Inc. | Method of preparing an eyeglass lens with a controller |
| US7052262B2 (en) | 2001-02-20 | 2006-05-30 | Q2100, Inc. | System for preparing eyeglasses lens with filling station |
| US7139636B2 (en) * | 2001-02-20 | 2006-11-21 | Q2100, Inc. | System for preparing eyeglass lenses with bar code reader |
| US7124995B2 (en) * | 2001-02-20 | 2006-10-24 | Q2100, Inc. | Holder for mold assemblies and molds |
| US6712331B2 (en) | 2001-02-20 | 2004-03-30 | Q2100, Inc. | Holder for mold assemblies with indicia |
| US6840752B2 (en) * | 2001-02-20 | 2005-01-11 | Q2100, Inc. | Apparatus for preparing multiple eyeglass lenses |
| US7037449B2 (en) | 2001-02-20 | 2006-05-02 | Q2100, Inc. | Method for automatically shutting down a lens forming apparatus |
| US6875005B2 (en) | 2001-02-20 | 2005-04-05 | Q1200, Inc. | Apparatus for preparing an eyeglass lens having a gating device |
| US6790022B1 (en) | 2001-02-20 | 2004-09-14 | Q2100, Inc. | Apparatus for preparing an eyeglass lens having a movable lamp mount |
| US6702564B2 (en) | 2001-02-20 | 2004-03-09 | Q2100, Inc. | System for preparing an eyeglass lens using colored mold holders |
| US7011773B2 (en) | 2001-02-20 | 2006-03-14 | Q2100, Inc. | Graphical interface to display mold assembly position in a lens forming apparatus |
| US6758663B2 (en) | 2001-02-20 | 2004-07-06 | Q2100, Inc. | System for preparing eyeglass lenses with a high volume curing unit |
| US6676399B1 (en) | 2001-02-20 | 2004-01-13 | Q2100, Inc. | Apparatus for preparing an eyeglass lens having sensors for tracking mold assemblies |
| US7051290B2 (en) * | 2001-02-20 | 2006-05-23 | Q2100, Inc. | Graphical interface for receiving eyeglass prescription information |
| US7074352B2 (en) | 2001-02-20 | 2006-07-11 | Q2100, Inc. | Graphical interface for monitoring usage of components of a lens forming apparatus |
| US7083404B2 (en) * | 2001-02-20 | 2006-08-01 | Q2100, Inc. | System for preparing an eyeglass lens using a mold holder |
| US6962669B2 (en) | 2001-02-20 | 2005-11-08 | Q2100, Inc. | Computerized controller for an eyeglass lens curing apparatus |
| US6655946B2 (en) | 2001-02-20 | 2003-12-02 | Q2100, Inc. | Apparatus for preparing an eyeglass lens having a controller for conveyor and curing units |
| US6863518B2 (en) | 2001-02-20 | 2005-03-08 | Q2100, Inc. | Mold filing apparatus having multiple fill stations |
| US6790024B2 (en) | 2001-02-20 | 2004-09-14 | Q2100, Inc. | Apparatus for preparing an eyeglass lens having multiple conveyor systems |
| US6612828B2 (en) | 2001-02-20 | 2003-09-02 | Q2100, Inc. | Fill system with controller for monitoring use |
| US6899831B1 (en) | 2001-02-20 | 2005-05-31 | Q2100, Inc. | Method of preparing an eyeglass lens by delayed entry of mold assemblies into a curing apparatus |
| US6726463B2 (en) | 2001-02-20 | 2004-04-27 | Q2100, Inc. | Apparatus for preparing an eyeglass lens having a dual computer system controller |
| US6808381B2 (en) | 2001-02-20 | 2004-10-26 | Q2100, Inc. | Apparatus for preparing an eyeglass lens having a controller |
| US6893245B2 (en) | 2001-02-20 | 2005-05-17 | Q2100, Inc. | Apparatus for preparing an eyeglass lens having a computer system controller |
| US6676398B2 (en) | 2001-02-20 | 2004-01-13 | Q2100, Inc. | Apparatus for preparing an eyeglass lens having a prescription reader |
| US7004740B2 (en) | 2001-02-20 | 2006-02-28 | Q2100, Inc. | Apparatus for preparing an eyeglass lens having a heating system |
| US7025910B2 (en) | 2001-02-20 | 2006-04-11 | Q2100, Inc | Method of entering prescription information |
| US6709257B2 (en) | 2001-02-20 | 2004-03-23 | Q2100, Inc. | Eyeglass lens forming apparatus with sensor |
| US6752613B2 (en) | 2001-02-20 | 2004-06-22 | Q2100, Inc. | Apparatus for preparing an eyeglass lens having a controller for initiation of lens curing |
| US7045081B2 (en) | 2001-02-20 | 2006-05-16 | Q2100, Inc. | Method of monitoring components of a lens forming apparatus |
| SE0101702D0 (en) * | 2001-05-15 | 2001-05-15 | Ardenia Investments Ltd | Novel potentiating compounds |
| US7044429B1 (en) | 2002-03-15 | 2006-05-16 | Q2100, Inc. | Methods and systems for coating eyeglass lens molds |
| US6464484B1 (en) | 2002-03-30 | 2002-10-15 | Q2100, Inc. | Apparatus and system for the production of plastic lenses |
| US6756745B1 (en) * | 2003-03-27 | 2004-06-29 | Tieng-Fu Lin | Four-electrode fluorescent lamp and the circuit for arranging the same |
| US10264629B2 (en) * | 2013-05-30 | 2019-04-16 | Osram Sylvania Inc. | Infrared heat lamp assembly |
| DK3211656T3 (en) * | 2016-02-23 | 2019-01-07 | Xylem Ip Man Sarl | LOW PRESSURE ULTRAVIOLET RADIATION SOURCE WITH MORE FILAMENTS |
Family Cites Families (18)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US1814499A (en) * | 1928-02-17 | 1931-07-14 | Electrons Inc | Circuits for discharge tubes |
| US2654042A (en) * | 1949-07-29 | 1953-09-29 | Gen Electric | Integrally capacitively ballasted discharge lamp |
| US2605432A (en) * | 1949-10-19 | 1952-07-29 | Electrons Inc | Indirectly heated cathode structure |
| US3225241A (en) * | 1959-07-09 | 1965-12-21 | Sylvania Electric Prod | Aperture fluorescent lamp |
| US3089972A (en) * | 1960-07-14 | 1963-05-14 | Westinghouse Electric Corp | Electric discharge device |
| US3328622A (en) * | 1964-07-14 | 1967-06-27 | Sylvania Electric Prod | Electric discharge device having primary and secondary electrodes |
| CH491578A (en) * | 1966-11-09 | 1970-05-31 | Elektro App Bau F Knobel & Co | Device for the ignition and operation of fluorescent lamps with heated cathodes |
| US3521122A (en) * | 1967-07-03 | 1970-07-21 | Sylvania Electric Prod | Incandescent-fluorescent lamp |
| US3717781A (en) * | 1969-09-19 | 1973-02-20 | Sylvania Electric Prod | Aperture fluorescent lamp having uniform surface brightness |
| US3733599A (en) * | 1970-09-22 | 1973-05-15 | Xerox Corp | Triggering apparatus for a flash lamp |
| JPS518779Y2 (en) * | 1972-02-07 | 1976-03-09 | ||
| JPS5229905Y2 (en) * | 1972-05-24 | 1977-07-08 | ||
| US3882349A (en) * | 1974-06-13 | 1975-05-06 | Burroughs Corp | Multi-position, gaseous discharge, character display panel including auxiliary, cathode transfer electrodes |
| JPS5124065U (en) * | 1974-08-12 | 1976-02-21 | ||
| NL7503826A (en) * | 1975-04-01 | 1976-10-05 | Philips Nv | DEVICE WITH A GAS AND / OR VAPOR DISCHARGE LAMP. |
| GB1571084A (en) * | 1975-12-09 | 1980-07-09 | Thorn Electrical Ind Ltd | Electric lamps and components and materials therefor |
| US4140385A (en) * | 1976-03-22 | 1979-02-20 | Xerox Corporation | Low pressure metal or metal halide lamps for photocopying applications |
| DE2748441A1 (en) * | 1977-10-26 | 1979-05-03 | Licentia Gmbh | Fluorescent lamp transistor inverter - uses triac controlled by state on ignition capacitor connected to secondary winding |
-
1980
- 1980-05-19 US US06/151,012 patent/US4329622A/en not_active Expired - Lifetime
-
1981
- 1981-04-29 CA CA000376481A patent/CA1155905A/en not_active Expired
- 1981-05-12 JP JP7128181A patent/JPS5711465A/en active Granted
- 1981-05-19 DE DE8181302231T patent/DE3172489D1/en not_active Expired
- 1981-05-19 EP EP81302231A patent/EP0040547B1/en not_active Expired
Also Published As
| Publication number | Publication date |
|---|---|
| EP0040547B1 (en) | 1985-10-02 |
| DE3172489D1 (en) | 1985-11-07 |
| JPH0353742B2 (en) | 1991-08-16 |
| JPS5711465A (en) | 1982-01-21 |
| US4329622A (en) | 1982-05-11 |
| EP0040547A1 (en) | 1981-11-25 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CA1155905A (en) | Low pressure gas discharge lamp with increased end illumination | |
| EP0270004B1 (en) | Gas discharge lamp and apparatus utilizing the same | |
| KR900002446B1 (en) | Inacrive gas discharge lamp device | |
| US5610477A (en) | Low breakdown voltage gas discharge device and methods of manufacture and operation | |
| CA1149078A (en) | Compact fluorescent light source having metallized electrodes | |
| US4871941A (en) | Gas discharge lamp with different film thicknesses | |
| US5289085A (en) | Capacitively driven RF light source having notched electrode for improved starting | |
| CA1106908A (en) | Two-wire ballast for fluorescent tube dimming | |
| US5773926A (en) | Electrodeless fluorescent lamp with cold spot control | |
| US5309061A (en) | Compact fluorescent lamp having incandescent lamp starting aid | |
| US2341990A (en) | Electric discharge device | |
| KR101212927B1 (en) | Inductively powered gas discharge lamp | |
| US4508993A (en) | Fluorescent lamp without ballast | |
| US5066892A (en) | Glow discharge lamp with incandescent filament | |
| CA1293765C (en) | Rare gas discharge lamp with an external electrode | |
| US4398123A (en) | High pressure discharge lamp | |
| US4797598A (en) | Illumination apparatus | |
| GB2114385A (en) | Cathode phasing circuits for discharge | |
| JPH04294051A (en) | Fluorescent lamp | |
| JPS63215159A (en) | Illuminator | |
| JPS63215158A (en) | Illuminator | |
| RU2094899C1 (en) | Radiation source | |
| JPH0697604B2 (en) | Electrodeless discharge lamp device | |
| JPH09245978A (en) | Fluorescent lamp lighting device, and office automation device using same | |
| JPH10188907A (en) | Hot cathode low-pressure discharge lamp and hot cathode low-pressure discharge lamp device |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKEX | Expiry |