Claims
- 1. An electric gas discharge lamp which includes: means for producing ultraviolet radiation comprising a translucent envelope, at least two spaced discharge electrodes sealed in said envelope and an ionized gas disposed within said envelope, said lamp further comprising at least first and second superposed layers carried on said envelope, said first layer being a luminescent material, said second layer being farther from a discharge between said electrodes than said first layer, said second layer consisting of a mixture of luminescent material and a white material which is non-luminescent and has an absorption for ultraviolet radiation of a wavelength of more than 240 nm which is less than 20% of the absorption of this radiation by that constituent of the luminescent material which has the smallest absorption for this radiation, the ratio of the amount of white material to the amount of luminescent material within any one layer versus any other layer increasing with the distance from the discharge.
- 2. Apparatus as claimed in claim 1, wherein said white material has an absorption for ultraviolet radiation of a wavelength longer than 240 nm which is less than 10% of the absorption of this radiation by that constituent of the luminescent which has the smallest absorption for this radiation.
- 3. Apparatus as claimed in claim 2 wherein the converted percentage of the ultraviolet radiation incident on the luminescent component layer facing the discharge lies between 80 and 99% of the total amount of ultraviolet radiation converted by the luminescent layer.
- 4. Apparatus as claimed in claim 3 wherein said percentage lies between 90 and 99%.
- 5. Apparatus as claimed in claim 4 wherein the mean grain size of the white non-luminescent material is smaller than the mean grain size of the luminescent material.
- 6. Apparatus as claimed in claim 5, wherein the white non-luminescent material is barium sulphate.
- 7. Apparatus as claimed in claim 5 wherein the white non-luminescent material is calcium pyrophosphate.
- 8. Apparatus as claimed in claim 7 wherein the luminescent layer is composed of two component layers.
Priority Claims (1)
Number |
Date |
Country |
Kind |
7406035 |
May 1974 |
NL |
|
Parent Case Info
This is a continuation of application Ser. No. 574,348, filed May 6, 1975, now abandoned.
US Referenced Citations (4)
Continuations (1)
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Number |
Date |
Country |
Parent |
574348 |
May 1975 |
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