CA1214195A - Electric lamp having a coloured lamp envelope - Google Patents
Electric lamp having a coloured lamp envelopeInfo
- Publication number
- CA1214195A CA1214195A CA000449092A CA449092A CA1214195A CA 1214195 A CA1214195 A CA 1214195A CA 000449092 A CA000449092 A CA 000449092A CA 449092 A CA449092 A CA 449092A CA 1214195 A CA1214195 A CA 1214195A
- Authority
- CA
- Canada
- Prior art keywords
- lamp
- layer
- light
- powder
- envelope
- 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
Classifications
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01K—ELECTRIC INCANDESCENT LAMPS
- H01K1/00—Details
- H01K1/28—Envelopes; Vessels
- H01K1/32—Envelopes; Vessels provided with coatings on the walls; Vessels or coatings thereon characterised by the material thereof
Landscapes
- Vessels And Coating Films For Discharge Lamps (AREA)
Abstract
ABSTRACT:
An electric lamp according to the invention has a lamp envelope (1) which at its inner surface is coated with two electrostatically applied powder layers. One layer (2a) comprises a cadmium pigment and a light-scattering powder and the other inner layer (2b) com-prises mainly light-scattering powder. In order to obtain comparable optical properties, in the lamp according to the invention a considerably smaller quantity of pigment is required than in conventional lamps having a single coating layer.
An electric lamp according to the invention has a lamp envelope (1) which at its inner surface is coated with two electrostatically applied powder layers. One layer (2a) comprises a cadmium pigment and a light-scattering powder and the other inner layer (2b) com-prises mainly light-scattering powder. In order to obtain comparable optical properties, in the lamp according to the invention a considerably smaller quantity of pigment is required than in conventional lamps having a single coating layer.
Description
Pl~ 10 622 l ~-10-1983 "Electric lamp having a coloured lamp envelopel'.
~ Le invention relates to an eleetrie latnp having a glass lamp envelope whieh is sealed in a vaeuum-tight manner and in which IS arranged a ligrht source connected to current-supply conductors e~tending through the wall of -the lamp envelope to the e~terior, said lamp envelope having on its inner surfaee an electro~tatieally applied coloured eoating which comprises a light-seattering powder and at least one eadmium pigmentO An ineandeseent l~np of this kind is known from United States Patent Specifieation lO 3 320,L~60-Such a lamp ean be used in an environment in which it has to be avoided that light attracts insec-ts, a.s a ~estive illumination lamp, a disc illumination lamp and the lil~e.
~lectrostatically applied powder layers have the advantage as compared to layers formed from a powder sus-pension that during application no solvents and binders are introdueed into the lamp envelopeO In faet the po~rder i5 dusted in a dry state in a lamp envelope ~rhose wall is given a positve potential ~ith respeet to the powderO
Under the infl~lenee thereo:~` the powder adheres to the wall~
An electrostatical1y applied powder layer has charaeteristie properties which distinguish the layer ~om a layer formed from a powder suspen~ion. The layer has a very low paelcing density~ whieh is even fi~ty times lower than that of a layer formed from a suspension of the same powder mi~ture. At its surface the layer has a very high degree o~ roughness as eompared with a smooth surface o~ a layer obtained from a suspension~ A noticeable dif~erence is further that, ~hen an electrostatically coated lamp envelope is observe~ along a tangen-t to the lamp envelope~
it is elearly visible that the ~rall of the lamp envelope has a eertain thiclcnessO On the contraryy with a lamp Pl-~ 10 ~2~ -2- 18-10-19~3 envelope coated by means of a suspension, the ~all thicl~ness o:~ the l~np en~eiope of the usual type 7 observed in the sc~me m~uler, is not percep-tible.
~le requirement is imposed on coloured lamps that they have the san1e colour both in operation and out o:~
opera-tion, that is to say with transmitted and incident light, respectively, while the coating scatters the light generated by the lamp so that the light source is not vi-~ible and the wall o:~ the lamp envelope is ~luminated uni~ormly It has been ~o~md that especially when deep colours are desired, cadmium compounds have to be used as pig1nents ~or several colours~ such as red, yellow, and colours formed therewith, sucll as orange. These pigments have a. la.rge colouring ~orce 9 as a result o~ which they colour the lamp intensely despite a mi~ing with light-scattering powder, Cadmium compounds moreover ha~e a high thermal stability. A disadv~ntage ofcadmiurtl compounds~
however~ is their toxieity c~nd this is the reason ~vhy it has to be avoided that at the end o~ the li~e o~ the lamps large quantities of these compo~Lnds s.ho~ up in the en~rironmentO
The invention has :~or its object to provi~e a co-loured lamp in which, whilst maintaining the colour pro perties of the lamp~ the content o~ cadmium compo~Lnds is low~ that is to say lower than in conventiona~ coloured l~nps~
According ~ the in~e:ntion, in a lamp o~ the kind described in the opening paragraph this is achieved in that the coating comprises a layer on said sur~ace o~ a mixture of light-scattering powder and pigmen-t powder and an overlying layer of mainly light-scattering po~derO
~ n a lamp accord;ng to the.United States Speci~ication mentioned in the opening paragraph, the coat-ing comprises a single layer o~ a homogeneous powder mix-ture. This layer has to be co1nparatively thicl~ in order toscatter to a su~icient e~tent the emitted light and -to ill~linate the lamp envelope ~mi~ormly. Further, the pig-ment content o~ the l~yer hæs to be comparatively hi.gh in gs Pl~ IO 6,~2 -3- 1~-10-19~3 orcler to provide ~or the lamp envelope the same colowr with incident ligh-t and wi-th -transmitted light. '~e mix-ture used according -to the a~orementioned United States Patent Speci-~ication comprises equal parts by weigllt o~ silicon dioxide S and cadn~ n sulphide.
In the lamp according to the in~entioll, a thin outer layer having a high pigment con-tent is su~icient.
Tlle thic~cness o~ -this layer and the content o~ pigment depend upon the colour satura-tion required ~or the lamp.
In general, the layer will have an average thickness o~ 5O
-to 7O /um and the pigment content will be 35 to 45 o~b by weight. The inner layer mainly comprises light-scattering powder and does not 9 or substantially does not contain pigment. The average thickness of the inner layer is con-nected with the desired extent o~ uni~ormity with whichthe lamp envelope is illuminated by the light source~ The inner layer will generally have an average thic~ne~s o~
approxi1nately 75 to 130 /~un, As compared with lamps having the sarme power~ the same colour and the same uni~ormity o~ illumination of the lamp envelope with a conventional elec-trostatically applied coating, the lamp according to the in~ention contains a considerably smaller quantity of pigment~ i.eO an up to 7O~/O smaller qu~ltity.
As the light-scattering constituent of the coating~
use is r~ostly made o~ silicon dioxide or a mi~ture o~
vc~rious silicon dioxides~ This constituent generally has a primary particle size lying mainly be-tween -IO and 3O nmO
Examples of cadmium cornpounds that can be used as pigment in the coating are cadmium sulphide (yellow)~
cadmium sulphoselenide (red)~ mixture of these two sub-stances (orange), cadmium sulphide/ultramarine blue (sodium polysulphide silico-aluminate) (green)~ The pigments have a primary particle size lying mainly between -IOO and ~5 5OOO nm.
Powce~- mixtures can be prepared in dry ~tate~ ~'or example~ in a "fluidizing mixer'!. In this case, the desired resistivit,v o~ the mi~tures can be ad~justed by ~, ~2~
Pl~ lO ~j22 ~ -l0-l9~S3 USillg bo-th a llydrophobic light-scattering material (having7 for e~ample, a resistivi-ty o~ lol4 l~) and a ~lydrophylic light-scattering material (having, ~or e~ample7 a resisti~
ty o~ 107:') 7 such clS silicon dio~ides.
In general, in -the lamp according to -the invention, a ~ilamen-t~ ~rhicll may be accommoclated in an inner envelope~
~ill be u-tilized as a light source. Ho~rever7 alternatives are high-pressure gas discharges, such as high-pressure sodium and high-pressure mercury vapour discharges.
10 ~3~
.
Lamps which during operation at 2ZO V consumed a power of 159 2~? 40 and 60 W~ respectively~ were rnanuractur-ed ~rith an A-60 lamp envelope, that is to say a lamp en-velope h~ving a spherically curved p~rt~ ~hose ma~imum 15 diameter is 60 mm9 and a neck-shaped part. The lamp en~elopes were invariably coated at their inner sur~ace with an outer electrostatically applied layer and an inner electro-statically applied layer. The outer layer had the rollowing composition:
20 Pigment 40 c/O by weight; hydrophobic SiO2 20 % by weight;
hydrophylic SiO2 40 ~/o by ~reight. The inner layer consisted of equal parts by weight o~ hydrophobic and hydropllylic SiO2. The average thicluness and the weight o~ the ou-ter and the inner layers were: 50 J~un~ 40 mg~ and 120 /um, 34 mg9 ~5 respectively.
'rhe lamps were mc~nu~actured in di~erent colours with cadmiun sulphide~ cadmium sulphoselenide-coprecipitate, cadmium sulphide/cadmi~umsulphoselenide-coprecipitate and cadmium sulphide~ultramarine blue~ respectively~ as pigmen-tO
For comparison~ conventiollal lamps were manu~actur-ed ~ith an electro3tatically applied coating cornprising a single layer consistlng of: 40/0 b~ weight o~ pigmen-t t 20%
by weight o~ hydrophylic SiO2, 40~0 by weight o~ hydrophobic SiO20 On an average the layer thickness ~as 145 /um and 35 the weigh-t was l40 mgO
The l~ps-according to the inven-tion in operation and out o~ operation had optical properties ~hich could not or substantially not be distinguished ~rom those o~ the s PHN I0 ~2~ -5- Ig-~ 3 conventiollal lamps. In lamps according to -the invelltion, however, the pigment weight was only 28.6 % o~ that o~ the convell-tional lamps .
~uring the applicati~n of the coating layers and S layer, respectively, -the lamp en~elope was given a positive potential o~ at leas-t l2 kV wi-tll respect to -the powder rni~ture to be applied.
~ n embodiment o~ the lamp according to the in-vention is shown in the drawing in side elevation, partly brol~en away~
In the Figure~ the lamp envelope I has at its inner sur~ace an electrostatically applied colour coating 2a~2br The coating comprises two layers. ~le outer layer 2a consists o~ a mixture o~ light-scattering powder and at least one cadmium pigment- the inner layer 2b mainly consists o~ light-scattering powderO ~ ~ilament 3 is arranged in the lamp en~elope as a light source. Current-supply conductors 4 carry the light source 3 and e~tend through the wall o~ the lamp en~relope l~ which is sealed in a vacu~lm~-tight manner~ to the exterior,where they are se-cured to contacts o~ a larnp cap 5 ~i~ed to the lamp en-velope.
~ Le invention relates to an eleetrie latnp having a glass lamp envelope whieh is sealed in a vaeuum-tight manner and in which IS arranged a ligrht source connected to current-supply conductors e~tending through the wall of -the lamp envelope to the e~terior, said lamp envelope having on its inner surfaee an electro~tatieally applied coloured eoating which comprises a light-seattering powder and at least one eadmium pigmentO An ineandeseent l~np of this kind is known from United States Patent Specifieation lO 3 320,L~60-Such a lamp ean be used in an environment in which it has to be avoided that light attracts insec-ts, a.s a ~estive illumination lamp, a disc illumination lamp and the lil~e.
~lectrostatically applied powder layers have the advantage as compared to layers formed from a powder sus-pension that during application no solvents and binders are introdueed into the lamp envelopeO In faet the po~rder i5 dusted in a dry state in a lamp envelope ~rhose wall is given a positve potential ~ith respeet to the powderO
Under the infl~lenee thereo:~` the powder adheres to the wall~
An electrostatical1y applied powder layer has charaeteristie properties which distinguish the layer ~om a layer formed from a powder suspen~ion. The layer has a very low paelcing density~ whieh is even fi~ty times lower than that of a layer formed from a suspension of the same powder mi~ture. At its surface the layer has a very high degree o~ roughness as eompared with a smooth surface o~ a layer obtained from a suspension~ A noticeable dif~erence is further that, ~hen an electrostatically coated lamp envelope is observe~ along a tangen-t to the lamp envelope~
it is elearly visible that the ~rall of the lamp envelope has a eertain thiclcnessO On the contraryy with a lamp Pl-~ 10 ~2~ -2- 18-10-19~3 envelope coated by means of a suspension, the ~all thicl~ness o:~ the l~np en~eiope of the usual type 7 observed in the sc~me m~uler, is not percep-tible.
~le requirement is imposed on coloured lamps that they have the san1e colour both in operation and out o:~
opera-tion, that is to say with transmitted and incident light, respectively, while the coating scatters the light generated by the lamp so that the light source is not vi-~ible and the wall o:~ the lamp envelope is ~luminated uni~ormly It has been ~o~md that especially when deep colours are desired, cadmium compounds have to be used as pig1nents ~or several colours~ such as red, yellow, and colours formed therewith, sucll as orange. These pigments have a. la.rge colouring ~orce 9 as a result o~ which they colour the lamp intensely despite a mi~ing with light-scattering powder, Cadmium compounds moreover ha~e a high thermal stability. A disadv~ntage ofcadmiurtl compounds~
however~ is their toxieity c~nd this is the reason ~vhy it has to be avoided that at the end o~ the li~e o~ the lamps large quantities of these compo~Lnds s.ho~ up in the en~rironmentO
The invention has :~or its object to provi~e a co-loured lamp in which, whilst maintaining the colour pro perties of the lamp~ the content o~ cadmium compo~Lnds is low~ that is to say lower than in conventiona~ coloured l~nps~
According ~ the in~e:ntion, in a lamp o~ the kind described in the opening paragraph this is achieved in that the coating comprises a layer on said sur~ace o~ a mixture of light-scattering powder and pigmen-t powder and an overlying layer of mainly light-scattering po~derO
~ n a lamp accord;ng to the.United States Speci~ication mentioned in the opening paragraph, the coat-ing comprises a single layer o~ a homogeneous powder mix-ture. This layer has to be co1nparatively thicl~ in order toscatter to a su~icient e~tent the emitted light and -to ill~linate the lamp envelope ~mi~ormly. Further, the pig-ment content o~ the l~yer hæs to be comparatively hi.gh in gs Pl~ IO 6,~2 -3- 1~-10-19~3 orcler to provide ~or the lamp envelope the same colowr with incident ligh-t and wi-th -transmitted light. '~e mix-ture used according -to the a~orementioned United States Patent Speci-~ication comprises equal parts by weigllt o~ silicon dioxide S and cadn~ n sulphide.
In the lamp according to the in~entioll, a thin outer layer having a high pigment con-tent is su~icient.
Tlle thic~cness o~ -this layer and the content o~ pigment depend upon the colour satura-tion required ~or the lamp.
In general, the layer will have an average thickness o~ 5O
-to 7O /um and the pigment content will be 35 to 45 o~b by weight. The inner layer mainly comprises light-scattering powder and does not 9 or substantially does not contain pigment. The average thickness of the inner layer is con-nected with the desired extent o~ uni~ormity with whichthe lamp envelope is illuminated by the light source~ The inner layer will generally have an average thic~ne~s o~
approxi1nately 75 to 130 /~un, As compared with lamps having the sarme power~ the same colour and the same uni~ormity o~ illumination of the lamp envelope with a conventional elec-trostatically applied coating, the lamp according to the in~ention contains a considerably smaller quantity of pigment~ i.eO an up to 7O~/O smaller qu~ltity.
As the light-scattering constituent of the coating~
use is r~ostly made o~ silicon dioxide or a mi~ture o~
vc~rious silicon dioxides~ This constituent generally has a primary particle size lying mainly be-tween -IO and 3O nmO
Examples of cadmium cornpounds that can be used as pigment in the coating are cadmium sulphide (yellow)~
cadmium sulphoselenide (red)~ mixture of these two sub-stances (orange), cadmium sulphide/ultramarine blue (sodium polysulphide silico-aluminate) (green)~ The pigments have a primary particle size lying mainly between -IOO and ~5 5OOO nm.
Powce~- mixtures can be prepared in dry ~tate~ ~'or example~ in a "fluidizing mixer'!. In this case, the desired resistivit,v o~ the mi~tures can be ad~justed by ~, ~2~
Pl~ lO ~j22 ~ -l0-l9~S3 USillg bo-th a llydrophobic light-scattering material (having7 for e~ample, a resistivi-ty o~ lol4 l~) and a ~lydrophylic light-scattering material (having, ~or e~ample7 a resisti~
ty o~ 107:') 7 such clS silicon dio~ides.
In general, in -the lamp according to -the invention, a ~ilamen-t~ ~rhicll may be accommoclated in an inner envelope~
~ill be u-tilized as a light source. Ho~rever7 alternatives are high-pressure gas discharges, such as high-pressure sodium and high-pressure mercury vapour discharges.
10 ~3~
.
Lamps which during operation at 2ZO V consumed a power of 159 2~? 40 and 60 W~ respectively~ were rnanuractur-ed ~rith an A-60 lamp envelope, that is to say a lamp en-velope h~ving a spherically curved p~rt~ ~hose ma~imum 15 diameter is 60 mm9 and a neck-shaped part. The lamp en~elopes were invariably coated at their inner sur~ace with an outer electrostatically applied layer and an inner electro-statically applied layer. The outer layer had the rollowing composition:
20 Pigment 40 c/O by weight; hydrophobic SiO2 20 % by weight;
hydrophylic SiO2 40 ~/o by ~reight. The inner layer consisted of equal parts by weight o~ hydrophobic and hydropllylic SiO2. The average thicluness and the weight o~ the ou-ter and the inner layers were: 50 J~un~ 40 mg~ and 120 /um, 34 mg9 ~5 respectively.
'rhe lamps were mc~nu~actured in di~erent colours with cadmiun sulphide~ cadmium sulphoselenide-coprecipitate, cadmium sulphide/cadmi~umsulphoselenide-coprecipitate and cadmium sulphide~ultramarine blue~ respectively~ as pigmen-tO
For comparison~ conventiollal lamps were manu~actur-ed ~ith an electro3tatically applied coating cornprising a single layer consistlng of: 40/0 b~ weight o~ pigmen-t t 20%
by weight o~ hydrophylic SiO2, 40~0 by weight o~ hydrophobic SiO20 On an average the layer thickness ~as 145 /um and 35 the weigh-t was l40 mgO
The l~ps-according to the inven-tion in operation and out o~ operation had optical properties ~hich could not or substantially not be distinguished ~rom those o~ the s PHN I0 ~2~ -5- Ig-~ 3 conventiollal lamps. In lamps according to -the invelltion, however, the pigment weight was only 28.6 % o~ that o~ the convell-tional lamps .
~uring the applicati~n of the coating layers and S layer, respectively, -the lamp en~elope was given a positive potential o~ at leas-t l2 kV wi-tll respect to -the powder rni~ture to be applied.
~ n embodiment o~ the lamp according to the in-vention is shown in the drawing in side elevation, partly brol~en away~
In the Figure~ the lamp envelope I has at its inner sur~ace an electrostatically applied colour coating 2a~2br The coating comprises two layers. ~le outer layer 2a consists o~ a mixture o~ light-scattering powder and at least one cadmium pigment- the inner layer 2b mainly consists o~ light-scattering powderO ~ ~ilament 3 is arranged in the lamp en~elope as a light source. Current-supply conductors 4 carry the light source 3 and e~tend through the wall o~ the lamp en~relope l~ which is sealed in a vacu~lm~-tight manner~ to the exterior,where they are se-cured to contacts o~ a larnp cap 5 ~i~ed to the lamp en-velope.
Claims
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS
1. An electric lamp having a glass lamp envelope which is sealed in a vacuum-tight manner and in which is arranged a light source connected to current-supply con-ductors extending through the wall of the lamp envelope to the exterior, said lamp envelope having on its inner surface an electrostatically applied coloured coating which comprises a light-scattering powder and at least one cadmium pigment, characterized in that the coating comprises a layer on said surface of a mixture of light-scattering powder and pigment powder, and an over-lying layer of mainly light-scattering powder.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| NL8300915 | 1983-03-14 | ||
| NL8300915 | 1983-03-14 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1214195A true CA1214195A (en) | 1986-11-18 |
Family
ID=19841546
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000449092A Expired CA1214195A (en) | 1983-03-14 | 1984-03-08 | Electric lamp having a coloured lamp envelope |
Country Status (3)
| Country | Link |
|---|---|
| EP (1) | EP0118962A1 (en) |
| JP (1) | JPS59177851A (en) |
| CA (1) | CA1214195A (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| NL8503477A (en) * | 1985-02-04 | 1986-09-01 | Philips Nv | ELECTRIC LAMP WITH AN ELECTROSTATICALLY COVERED LAMP VESSEL. |
| EP1292966A1 (en) * | 2000-06-07 | 2003-03-19 | Koninklijke Philips Electronics N.V. | High-pressure discharge lamp |
Family Cites Families (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US1765242A (en) * | 1924-09-15 | 1930-06-17 | Gen Electric | Lamp bulb |
| US3619695A (en) * | 1968-03-09 | 1971-11-09 | Tokyo Shibaura Electric Co | Fog lamp |
| US4081709A (en) * | 1975-11-20 | 1978-03-28 | General Electric Company | Electrostatic coating of silica powders on incandescent bulbs |
| JPS5842943B2 (en) * | 1978-11-06 | 1983-09-22 | ウエスチングハウス エレクトリック コ−ポレ−ション | Light source for object illumination |
-
1984
- 1984-03-08 CA CA000449092A patent/CA1214195A/en not_active Expired
- 1984-03-09 EP EP84200339A patent/EP0118962A1/en not_active Ceased
- 1984-03-12 JP JP4697584A patent/JPS59177851A/en active Pending
Also Published As
| Publication number | Publication date |
|---|---|
| JPS59177851A (en) | 1984-10-08 |
| EP0118962A1 (en) | 1984-09-19 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKEX | Expiry |