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EP0124175B1
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EP
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Low-pressure mercury vapour discharge lamp
Assignee: Koninklijke Philips NV
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Filing: 1984-04-24
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Granted: 1986-07-30
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Expires: 2004-04-24
Abstract
Abstract A low-pressure mercury vapour discharge lamp having a very satisfactory colour rendition, (R(a,8) ≥ 85), a colour temperature of 2300-3300 K and a colour point on or near the Planckian curve. The lamp is provided with a luminescent layer comprising:a. a luminescent alkaline earth metal halophosphate activated by Sb<sup>3+</sup> and Mn<sup>2+</sup> having a colour temperature of 2900-5000 K;b. a luminescent material activated by Eu<sup>2+</sup> with an emission maximum van 470-500 nm and a half-value width of at most 90 nm, andc. a luminescent rare earth metal metaborate activated by Ce<sup>3+</sup> and Mn<sup>2+</sup>, having a fundamental lattice Ln (Mg, Zn, Cd) B<sub>5</sub>O<sub>10</sub>, in which Ln represents the elements Y, La and/or Gd, which borate has red Mn<sup>2+</sup> emission.Further, the lamp is provided with means for absorbing blue radiation having wavelengths below 480 nm. Preferably, the luminescent layer further contains:d. a luminescent material activated by Tb<sup>3+</sup> which exhibits green Tb<sup>3+</sup> emission.Besides a very satisfactory colour rendition at a low colour temperature, these lamps have a high luminous flux and a high maintenance of the luminous flux during their life.
Inventors
- 👤 Johannes Trudo Cornelis Van Kemenade
- 👤 Johannes Theodorus Wilhelmus De Hair
- 👤 Everhardus Gradus Berns
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-23 13:12
CPC Classifications
H; H01; H01J; H01J61/00; H01J61/02; H01J61/38; H01J61/42; H01J61/44
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
232 words
A low-pressure mercury vapour discharge lamp having a very satisfactory colour rendition, a colour temperature of the emitted white light in the range of 2300 to 3300 K and a colour point on or near the Planckian curve and provided with a gas-tight radiation-transparent envelope containing mercury and a rare gas and with a luminescent layer comprising a luminescent halophosphate and a luminescent material activated by bivalent europium, characterized in that the luminescent layer comprises: a. at least one luminescent alkaline earth metal halophosphate activated by trivalent antimony and bivalent manganese and having a colour temperature of the emitted radiation of 2900 to 5000 K; b. at least one luminescent material activated by bivalent europium with an emission maximum in the range of 470 to 500 nm and a half-value width of the emission band of at most 90 nm, and c. a luminescent rare earth metal metaborate activated by trivalent cerium and bivalent manganese, having a monoclinic crystal structure, whose fundamental lattice corresponds to the formula Ln(Mg,Zn,Cd)B 5 O 10 , in which Ln is at least one of the elements yttrium, lanthanum and gadolinium and in which up to 20 mol.% of the B can be replaced by AI and/or Ga, which metaborate exhibits red Mn 2+ emission, and in that the lamp is provided with means for absorbing at least in part blue radiation having wavelengths below 480 nm.
Claim 2
Dependent Claim
232 words
A low-pressure mercury vapour discharge lamp having a very satisfactory colour rendition, a colour temperature of the emitted white light in the range of 2300 to 3300 K and a colour point on or near the Planckian curve and provided with a gas-tight radiation-transparent envelope containing mercury and a rare gas and with a luminescent layer comprising a luminescent halophosphate and a luminescent material activated by bivalent europium, characterized in that the luminescent layer comprises: a. at least one luminescent alkaline earth metal halophosphate activated by trivalent antimony and bivalent manganese and having a colour temperature of the emitted radiation of 2900 to 5000 K; b. at least one luminescent material activated by bivalent europium with an emission maximum in the range of 470 to 500 nm and a half-value width of the emission band of at most 90 nm, and c. a luminescent rare earth metal metaborate activated by trivalent cerium and bivalent manganese, having a monoclinic crystal structure, whose fundamental lattice corresponds to the formula Ln(Mg,Zn,Cd)B 5 O 10 , in which Ln is at least one of the elements yttrium, lanthanum and gadolinium and in which up to 20 mol.% of the B can be replaced by AI and/or Ga, which metaborate exhibits red Mn 2+ emission, and in that the lamp is provided with means for absorbing at least in part blue radiation having wavelengths below 480 nm.
Claim 3
Dependent Claim
30 words
A lamp as claimed in Claim 1, characterized in that the luminescent layer further contains a luminescent material activated by trivalent terbium (material d), which exhibits green Tb 3+ emission.
Claim 4
Dependent Claim
55 words
A lamp as claimed in Claim 2, characterized in that the luminescent metaborate c is further activated by trivalent terbium, the metaborate c being at the same time the material d, and corresponds to the formula in which and in which up to 20 mol.% of the B can be replaced by AI and/or Ga.
Claim 5
Dependent Claim
28 words
A lamp as claimed in Claim 1, 2 or 3, characterized in that the means for absorbing blue radiation are constituted by the radiation-transparent envelope of the lamp.
Claim 6
Dependent Claim
27 words
A lamp as claimed in any of Claims 1, 2 or 3, characterized in that the means for absorbing blue radiation are constituted by a yellow pigment.
Claim 7
Dependent Claim
22 words
A lamp as claimed in Claim 5, characterized in that the pigment is mixed with the luminescent materials of the luminescent layer.
Claim 8
Dependent Claim
39 words
A lamp as claimed in Claim 5, characterized in that the pigment is provided on the inner side of the lamp envelope as an absorption layer, on which the luminescent layer is disposed on the side facing the discharge.
Claim 9
Dependent Claim
71 words
A lamp as claimed in any of Claims 1, 2 or 3, characterized in that the means for absorbing blue radiation are constituted by a luminescent aluminate activated by trivalent cerium having a garnet crystal structure according to the formula M 3-j Ce j Al 5-k-p Ca k Sc p O 12 , in which M is at least one of the elements yttrium, gadolinium, lanthanum and lutetium and in which
Claim 10
Dependent Claim
15 words
A lamp as claimed in Claim 8, characterized in that M is yttrium and k=p=0.
Claim 11
Dependent Claim
29 words
A lamp as claimed in Claim 8 or 9, characterized in that the garnet activated by Ce 3+ is mixed with the remaining luminescent materials of the luminescent layer.
Claim 12
Dependent Claim
45 words
A lamp as claimed in Claim 8 or 9, characterized in that the garnet activated by Ce 3+ is applied on the inner side of the lamp envelope as an absorption layer on which the luminescent layer is disposed on the side facing the discharge.
Claim 13
Dependent Claim
61 words
A lamp as claimed in any one of Claims 1 to 11, characterized in that the material b is a luminescent aluminate activated by bivalent europium corresponding to the formula Sr 1-q-r Ca q Eu r Al s O 1½S+1 , in which and which aluminate has its emission maximum at 485-495 nm and has a half-value width of 55-75 nm.
Claim 14
Dependent Claim
49 words
A lamp as claimed in anyone of Claims 1 to 11, characterized in that the material b is a luminescent aluminate activated by bivalent europium corresponding to the formula in which and which aluminate has its emission maximum at 475-485 nm and has a half-value width of 70-90 nm.
Claim 15
Dependent Claim
50 words
A lamp as claimed in any one of Claims 1 to 11, characterized in that the material b is a luminescent borate phosphate activated by bivalent europium corresponding to the formula in which which borate-phosphate has its emission maximum at 470-485 nm and has a half-value width of 80-90 nm.
References Cited (Backward Citations)
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