US4748391A
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Yellow green barium lanthanum silicate oxyapatite phosphor, a fluorescent lamp containing the same, and a method thereof
Assignee: Osram Sylvania Inc
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Filing: 1986-12-18
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Granted: 1988-05-31
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Expires: 2006-12-18
Abstract
Abstract A method for preparing a barium lanthanum silicate oxyapatite europium activated phosphor and a barium lanthanum silicate oxyapatite manganese 2+ and europium 2+ or europium 2+ activated phosphor having a yellow green emission when activated by 254 nm excitation comprises the steps of forming a water slurry of the raw materials followed by calcining at approximately 1050° C. to form a powder. The powder is then heated to approximately 1500° C. in a reducing atmosphere to form the phosphor having a yellow green emission activated by a 254 nm excitation. Fluorescent lamps containing the yellow green emitting phosphors are described.
Inventors
- 👤 A. Gary Sigai
- 👤 Michael N. Alexander
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 16:48
CPC Classifications
C; C09; C09K; C09K11/00; C09K11/08; C09K11/77; C09K11/7783; C09K11/77922
Claims Analysis
Total Claims: 22
Claim 1
Independent Claim
145 words
A method of preparing a yellow green emitting barium lanthanum silicate oxyapatite phosphor activated by manganese +2 and europium +2 having a composition defined by the general formula: Ba 2 La 8 (SiO 2 ) 6 O 2 :Mn,Eu in which Mn and Eu are in the divalent state comprising the following steps: Step 1--forming a water slurry of lanthanum oxide, europium oxide, manganese carbonate, silicic acid, barium nitrate, and a dispersing agent; Step 2--drying the product from step 1 to form a powder; Step 3--calcining the product of step 2 at about 1050° C. and cooling to form a calcined powder; Step 4--heating the product from step 3 in a reducing atmosphere at a temperature and for a time sufficient to form a phosphor having a yellow green emission exhibiting characteristic wavelengths essentially as depicted in FIG. 2 when activated by 254 nm excitation.
Claim 2
Independent Claim
145 words
A method of preparing a yellow green emitting barium lanthanum silicate oxyapatite phosphor activated by manganese +2 and europium +2 having a composition defined by the general formula: Ba 2 La 8 (SiO 2 ) 6 O 2 :Mn,Eu in which Mn and Eu are in the divalent state comprising the following steps: Step 1--forming a water slurry of lanthanum oxide, europium oxide, manganese carbonate, silicic acid, barium nitrate, and a dispersing agent; Step 2--drying the product from step 1 to form a powder; Step 3--calcining the product of step 2 at about 1050° C. and cooling to form a calcined powder; Step 4--heating the product from step 3 in a reducing atmosphere at a temperature and for a time sufficient to form a phosphor having a yellow green emission exhibiting characteristic wavelengths essentially as depicted in FIG. 2 when activated by 254 nm excitation.
Claim 3
Dependent Claim
48 words
A method in accordance with claim 1 wherein said barium nitrate, lanthanum oxide, silicic acid, manganese carbonate, europium oxide are added in an amount based on a molecular formulation (Ba 0 .98 Eu 0 .01 Mn 0 .01) 2 La 8 (SiO 4 ) 6 O 2 .
Claim 4
Dependent Claim
27 words
A method in accordance with claim 1 wherein said reducing atmosphere comprises a dry forming gas at a gas flow rate of approximately 0.5 liters per min.
Claim 5
Dependent Claim
44 words
A method in accordance with claim 1 wherein said step 4 comprises heating the product from step 3 to about 1500° C. in about one hour and holding at 1500° C. for about three hours then cooling to room temperature in about one hour.
Claim 6
Dependent Claim
30 words
A method in accordance with claim 1 wherein said phosphor comprises cations of about 11.9 wt.% barium, 0.18 wt.% europium, 0.05 wt.% manganese, 61.9 wt.% lanthanum, and 8.0 wt.% silica.
Claim 7
Dependent Claim
98 words
A fluorescent lamp comprising a light-transmitting envelope having electrodes, an inert ionizable gas and a charge of mercury therein and a coating of a phosphor on the inside surface of said envelope, said phosphor comprising a yellow green emitting barium lanthanum silicate oxyapatite activated by manganese 2+ and europium 2+ exhibiting characteristic wavelengths essentially as depicted in FIG. 2 and having a composition defined by the general formula: Ba 2 La 8 (SiO 2 ) 6 O 2 :Mn,Eu in which Mn and Eu are in the divalent state made in accordance with the method of claim 1.
Claim 8
Dependent Claim
32 words
A fluorescent lamp in accordance with claim 6 in which said phosphor comprises cations of about 11.9 wt.% barium, 0.18 wt.% europium, 0.05 wt.% manganese, 61.9 wt.% lanthanum, and 8.0 wt.% silica.
Claim 9
Independent Claim
138 words
A method of preparing a yellow green emitting barium lanthanum silicate oxyapatite phosphor activated by europium 2+ having a composition defined by the general formula: Ba 2 La 8 (SiO 2 ) 6 O 2 :Eu in which Eu is in the divalent state comprising the following steps: Step 1--forming a water slurry of lanthanum oxide, europium oxide, silicic acid, barium nitrate, and a dispersing agent; Step 2--drying the product from step 1 to form a powder; Step 3--calcining the product of step 2 at about 1050° C. and cooling to form a calcined powder; Step 4--heating the product of step 3 in a reducing atmosphere at a temperature and for a time sufficient to form a phosphor having a yellow green emission exhibiting characteristic wavelengths essentially as depicted in FIG. 1 when activated by 254 nm radiation.
Claim 10
Independent Claim
138 words
A method of preparing a yellow green emitting barium lanthanum silicate oxyapatite phosphor activated by europium 2+ having a composition defined by the general formula: Ba 2 La 8 (SiO 2 ) 6 O 2 :Eu in which Eu is in the divalent state comprising the following steps: Step 1--forming a water slurry of lanthanum oxide, europium oxide, silicic acid, barium nitrate, and a dispersing agent; Step 2--drying the product from step 1 to form a powder; Step 3--calcining the product of step 2 at about 1050° C. and cooling to form a calcined powder; Step 4--heating the product of step 3 in a reducing atmosphere at a temperature and for a time sufficient to form a phosphor having a yellow green emission exhibiting characteristic wavelengths essentially as depicted in FIG. 1 when activated by 254 nm radiation.
Claim 11
Dependent Claim
44 words
A method in accordance with claim 8 wherein said lanthanum oxide, europium oxide, silicic acid, and barium nitrate are added in an amount based on a molecular formulation (Ba 0 .99 Eu 0 .01) 2 La 8 (SiO 4 ) 6 O 2 .
Claim 12
Dependent Claim
27 words
A method in accordance with claim 8 wherein said reducing atmosphere comprises a dry forming gas at a gas flow rate of approximately 0.5 liters per min.
Claim 13
Dependent Claim
44 words
A method in accordance with claim 8 wherein said step 4 comprises heating the product from step 3 to about 1500° C. in about one hour and holding at 1500° C. for about three hours then cooling to room temperature in about one hour.
Claim 14
Dependent Claim
27 words
A method in accordance with claim 8 wherein said phosphor comprises cations of about 13.4 wt.% barium, 0.14 wt.% europium, 61.3 wt.% lanthanum, and 7.9 wt.% silica.
Claim 15
Dependent Claim
93 words
A fluorescent lamp comprising a light-transmitting envelope having electrodes, an inert ionizable gas and a charge of mercury therein and a coating of a phosphor on the inside surface of said envelope, said phosphor comprising a yellow green emitting barium lanthanum oxyapatite silicate activated by europium 2+ exhibiting characteristic wavelengths essentially as depicted in FIG. 1 and having a composition defined by the general formula: Ba 2 La 8 (SiO 2 ) 6 O 2 :Eu in which Eu is in the divalent state made in accordance with the method of claim 8.
Claim 16
Dependent Claim
28 words
A fluorescent lamp in accordance with claim 13 wherein said phosphor comprises cations of about 13.4 wt.% barium, 0.14 wt.% europium, 61.3 wt.% lanthanum, and 7.9 wt.% silica.
Claim 17
Dependent Claim
50 words
A yellow green emitting phosphor exhibiting characteristic emission wavelengths essentially as depicted in FIG. 1 when excited by 254 nm excitation, said phosphor having a composition defined by the general formula: Ba 2 La 8 (SiO 2 ) 6 O 2 :Eu in which Eu is in the divalent state.
Claim 18
Dependent Claim
50 words
A yellow green emitting phosphor exhibiting characteristic emission wavelengths essentially as depicted in FIG. 1 when excited by 254 nm excitation, said phosphor having a composition defined by the general formula: Ba 2 La 8 (SiO 2 ) 6 O 2 :Eu in which Eu is in the divalent state.
Claim 19
Dependent Claim
31 words
A yellow green emitting phosphor in accordance with claim 15 wherein said general formula being (Ba 0 .99 Eu 0 .01) 2 La 8 (SiO 4 ) 6 O 2 .
Claim 20
Dependent Claim
53 words
A yellow green emitting phosphor exhibiting characteristic emission wavelengths essentially as depicted in FIG. 2 when excited by 254 nm excitation, said phosphor having a composition defined by the general formula: Ba 2 La 8 (SiO 2 ) 6 O 2 :Mn, Eu in which Mn and Eu are in the divalent state.
Claim 21
Dependent Claim
53 words
A yellow green emitting phosphor exhibiting characteristic emission wavelengths essentially as depicted in FIG. 2 when excited by 254 nm excitation, said phosphor having a composition defined by the general formula: Ba 2 La 8 (SiO 2 ) 6 O 2 :Mn, Eu in which Mn and Eu are in the divalent state.
Claim 22
Dependent Claim
34 words
A yellow green emitting phosphor in accordance with claim 17 wherein said general formula being (Ba 0 .98 Eu 0 .01 Mn 0 .01) 2 La 8 (SiO 4 ) 6 O 2 .
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
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| 3.5 Years (Year 4) | 1991-05-31 | 1991-11-30 | 1992-05-31 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-05-31 | 1995-11-30 | 1996-05-31 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-05-31 | 1999-11-30 | 2000-05-31 | $7700.00 | Window Closed / Lapsed |