US3668142A
Expired / Lapsed
US
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Preparation of phosphors
Assignee: Eastman Kodak Co
•
Filing: 1970-11-16
•
Granted: 1972-06-06
•
Expires: 1990-11-16
Abstract
Abstract Inorganic phosphors are prepared by separately introducing the anions and cations to form the phosphor into a reaction solution; maintaining in the reaction solution, throughout the reaction, an excess of up to 1 molar of the anion or cation; preventing local excesses of anions and cations; and, growing crystals of the phosphor to at least 0.5 micron.
Inventors
- 👤 George William Luckey
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 13:10
CPC Classifications
C; C09; C09K; C09K11/00; C09K11/08; C09K11/77; C09K11/7728; C09K11/7737; C09K11/7738; C01; C01B; C01B25/00; C01B25/16; C01B25/26; C01B25/32; C01B25/325; C01F; C01F11/00; C01F11/18; C01F11/186; C01F11/188; C01F11/20; C01F11/46; C01F11/462; C01F17/00; C01F17/30; C01F17/36; C01F17/38; C01G; C01G21/00; C01G21/20; C01G41/00; C09K11/0827; C09K11/0833; C09K11/61; C09K11/615; C09K11/616; C09K11/65; C09K11/66; C09K11/668; C09K11/67; C09K11/68; C01P; C01P2002/00; C01P2002/50; C01P2004/00; C01P2004/20; C01P2004/60; C01P2004/61; C01P2004/62; C01P2006/00; C01P2006/10; C01P2006/60
Claims Analysis
Total Claims: 76
Claim 1
Independent Claim
42 words
The method of forming phosphors as defined in claim 1 wherein said anion and said cation, each, are introduced into said solution in which said phosphors are formed at the rate of up to 0.4 mole per liter of solution per minute.
Claim 2
Dependent Claim
57 words
The method of forming phosphors as defined in claim 2 wherein said solution contains, throughout the reaction, an excess selected from an excess of anion over cation and an excess of cation over anion, said excess being chosen to provide the most efficient luminescence of the phosphor being formed, and said excess being up to 1 molar.
Claim 3
Dependent Claim
19 words
The method of forming phosphors as defined in claim 2 wherein said excess maintained is up to 0.5 molar.
Claim 4
Dependent Claim
55 words
The method of forming phosphors as defined in claim 2 wherein said solution contains, throughout the reaction, an excess selected from an excess of anion over cation anD an excess of cation over anion, said excess being chosen to provide efficient luminescence of the phosphor being formed, and said excess being up to 0.1 molar.
Claim 5
Dependent Claim
46 words
The method of forming phosphors as defined in claim 1 wherein said anion and said cation are introduced into said solution from separate solutions of said anion and cation, each of said separate solutions containing a concentration of up to 1.5 molar, respectively, anion and cation.
Claim 6
Dependent Claim
46 words
The method of forming phosphors as defined in claim 4 wherein said anion and said cation are introduced into said solution from separate solutions of said anion and cation, each of said separate solutions containing a concentration of up to 1 molar, respectively, anion and cation.
Claim 7
Dependent Claim
46 words
The method of forming phosphors as defined in claim 5 wherein said anion and said cation are introduced into said solution from separate solutions of said anion and cation, each of said separate solutions containing a concentration of up to 0.5 molar, respectively, anion and cation.
Claim 8
Dependent Claim
23 words
The method of forming phosphors as defined in claim 6 wherein said phosphors are grown to a size of at least 1 micron.
Claim 9
Dependent Claim
26 words
The method of forming phosphors as defined in claim 1 wherein said local excesses are prevented by agitating the solution in which said phosphors are formed.
Claim 10
Dependent Claim
19 words
The method of forming phosphors in accordance with claim 1 wherein the phosphors are ripened at an elevated temperature.
Claim 11
Dependent Claim
24 words
The method of forming phosphors as defined in claim 11 wherein the phosphors are ripened in the solution in which said phosphors are formed.
Claim 12
Dependent Claim
37 words
The method of forming phosphors as defined in claim 1 wherein said phosphors are selected from the group consisting of phosphors containing at least one covalently bonded atom in the molecule thereof, and phosphors containing fluoride ion.
Claim 13
Dependent Claim
90 words
The method of forming phosphors as defined in claim 6 wherein the anion of said phosphor is selected from the group consisting of sulfate, fluoride, tungstate, carbonate, silicate, vanadate, phosphate, arsenate, borate, sulfide and molybdate and the activator element different from the phosphor host material cation and anion is selected from the group consisting of lead, thallium, copper, manganese and a rare earth and the cation of said phosphors is selected from the group consisting of the elements which are cations in Series 3 through 11 of Mendeleeff''s Periodic Table.
Claim 14
Dependent Claim
13 words
The method of forming barium lead sulfate phosphor as defined in claim 1.
Claim 15
Independent Claim
121 words
The method of preparing barium lead sulfate phosphors which comprises: a. simultaneously introducing barium and lead ions into a solution in which said phosphors are formed at the rate of less than about 0.1 mole combined barium and lead ions per liter of solution in which said phosphors are formed per minute; b. maintaining an excess of sulfate ions in the solution in which said phosphors are formed of less than about 0.5 molar over the amount required to react with the barium and lead ions in the solution in which said phosphors are formed; c. agitating the solution in which said phosphors are formed; and, d. precipitating crystals of barium lead sulfate having a size of at least 0.5 micron.
Claim 16
Dependent Claim
43 words
The method of preparing barium lead sulfate phosphors as defined in claim 16 wherein an univalent cation is maintained in the solution in which said phosphors are formed in an amount sufficient to effectively enhance the fluorescence of the barium lead sulfate phosphors.
Claim 17
Dependent Claim
46 words
The method of preparing barium lead sulfate phosphors as defined in claim 16 wherein said barium and lead ions are introduced into the solution in which said phosphors are formed from a solution containing a concentration of less than about 0.5 molar barium and lead ions.
Claim 18
Dependent Claim
66 words
The method of preparing barium lead sulfate phosphors as defined in claim 18 wherein said solution in which said phosphors are formed has solubility characteristics for bariuM lead sulfate phosphors substantially equivalent to an aqueous acidic solution having a pH of less than about 2, and containing sulfate ions at a concentration of less than about 0.5 molar, at a temperature of 70* to 100* C.
Claim 19
Dependent Claim
67 words
The method of preparing barium lead sulfate phosphors as defined in claim 19 wherein said barium and lead ions are introduced into the solution in which said phosphors are formed at the rate of less than about 0.04 mole barium and lead ions per liter of solution in which said phosphors are formed per minute; and, said excess of sulfate ions is less than about 0.1 molar.
Claim 20
Independent Claim
304 words
The method of preparing barium lead sulfate phosphors which comprises: a. providing an aqueous solution in which said phosphors are formed; b. introducing into the aqueous solution in which said phosphors are formed a plurality of streams of aqueous solutions of water soluble barium and lead salts, said solutions containing concentrations of barium and lead ions of less than about 0.5 molar, and controlling the addition of said solutions so that the combined addition of barium and lead ions to the aqueous solution in which said phosphors are formed is at the rate of less than about 0.04 mole combined barium and lead ions per liter of solution in which said phosphors are formed per minute; c. introducing into the aqueous solution in which said phosphors are formed an aqueous solution containing a water soluble sulfate salt, said solution having a concentration of sulfate ion of not greater than about 1.5 molar, and controlling the addition of the aqueous sulfate solution so that there is in the aqueous solution in which said phosphors are formed an excess of sulfate ion over that required to react with the barium and lead ions in the solution in which said phosphors are formed at any given time during the precipitation, said excess being less than 0.1 molar; d. holding the pH of the solution in which said phosphors are formed throughout the precipitation at less than about 1 with the addition of an acid selected from the group consisting of hydrochloric, hydrobromic, trifluoroacetic, trichloroacetic, dichloroacetic, monochlorodifluoroacetic, benzene sulfonic, perchloric and hypophosphorous acids; e. maintaining the temperature of the solution in which said phosphors are formed throughout the precipitation in the range of about 70* to 100* C; and, f. agitating the solution in which said phosphors are formed during the precipitation of the barium lead sulfate phosphors.
Claim 21
Independent Claim
345 words
The method of preparing barium lead sulfate phosphors which comprises: a. providing an aqueous solution in which said phosphors are formed; b. introducing into the aqueous solution in which said phosphors are formed a plurality of streams of aqueous solutions of water soluble barium and lead salts, said solutions containing concentrations of barium and lead ions of less than about 0.5 molar, and controlling the addition of said solutions so that the combined addition of barium and lead ions to the aqueous solution in which said phosphors are formed is at the rate of less than about 0.04 mole combined barium and lead ions per liter of solution in which said phosphors are formed per minute; c. introducing into the aqueous solution in which said phosphors are formed an aqueous solution containing a water soluble sulfate salt, said solution having a concentration of sulfate ion of not greater than about 1.5 molar, and controlling the addition of the aqueous sulfate solution so that there is in the aqueous solution in which said phosphors are formed an excess of sulfate ion over that required to react with the barium and lead ions in the solution in which said phosphors are formed at any given time during the precipitation, said excess being less than 0.1 molar; d. maintaining in the solution in which said phosphors are formed an univalent cAtion selected from the group consisting of lithium, sodium, cesium, potassium and ammonium in an amount sufficient to effectively enhance the fluorescence of the barium lead sulfate phosphors; e. holding the pH of the solution in which said phosphors are formed throughout the precipitation at less than about 1 with the addition of an acid selected from the group consisting of hydrochloric, hydrobromic, trifluoroacetic, trichloroacetic, dichloroacetic, monochlorodifluoroacetic, benzene sulfonic, perchloric and hypophosphorous acids; f. maintaining the temperature of the solution in which said phosphors are formed throughout the precipitation in the range of about 70* to 100* C; and, g. agitating the solution in which said phosphors are formed during the precipitation of the barium lead sulfate phosphors.
Claim 22
Independent Claim
253 words
The method of preparing barium lead sulfate phosphors which comprises: a. providing an aqueous solution in which said phosphors are formed; b. introducing into the aqueous solution in which said phosphors are formed a plurality of streams of aqueous solutions of water soluble barium and lead salts, said solutions containing concentrations of barium and lead ions of less than about 0.5 molar, and controlling the addition of said solutions so that the combined addition of barium and lead ions into the aqueous solution in which said phosphors are formed is at the rate of less than about 0.1 mole combined barium and lead ions per liter of solution in which said phosphors are formed per minute; c. introducing into the aqueous solution in which said phosphors are formed an aqueous solution containing a water soluble sulfate salt, and controlling the addition of the aqueous sulfate solution so that there is in the aqueous solution an excess of sulfate ion over that required to react with the barium and lead ions in the solution in which said phosphors are formed at any given time during the precipitation, said excess being less than 0.5 molar; d. holding the pH of the solution in which said phosphors are formed throughout the precipitation at less than about 2 with the addition of an acid which does not substantially decrease the fluorescence of the barium lead sulfate phosphors; and e. agitating the solution in which said phosphors are formed during the precipitation of the barium lead sulfate phosphors.
Claim 23
Independent Claim
171 words
The method of preparing barium lead sulfate phosphors which comprises: a. providing an aqueous solution in which said phosphors are formed; b. introducing barium and lead ions into the solution in which said phosphors are formed at the rate of less than about 0.1 mole combined barium and lead ions per liter of solution in which said phosphors are formed per minute; c. maintaining in the solution in which said phosphors are formed an excess of sulfate ion over that required to react with the barium and lead ions in the solution in which said phosphors are formed at any time during the precipitation, said excess being less than 0.5 molar; d. holding the pH of the solution in which said phosphors are formed throughout the precipitation at less than about 2 with the addition of an acid which does not substantially decrease the fluorescence of the barium lead sulfate phosphors; and e. agitating the solution in which said phosphors are formed during the precipitation of the barium lead sulfate phosphors.
Claim 24
Independent Claim
199 words
The method of preparing barium lead sulfate phosphors which comprises: a. providing an aqueous solution in which said phosphors are formed; b. introducing barium and lead ions into the solution in which said phosphors are formed at the rate of less than about 0.1 mole combined barium and lead ions per liter of solution in which said phosphors are formed per minute; c. maintaining in the solution in which said phosphors are formed an excess of sulfate ion over that required to react with the barium and leaD ions in the solution in which said phosphors are formed at any time during the precipitation, said excess being less than 0.5 molar; d. maintaining in the solution in which said phosphors are formed an univalent cation in an amount to effectively enhance the fluorescence of the barium lead sulfate phosphors; e. holding the pH of the solution in which said phosphors are formed throughout the precipitation at less than about 2 with the addition of an acid which does not substantially decrease the fluorescence of the barium lead sulfate phosphors; and f. agitating the solution in which said phosphors are formed during the precipitation of the barium lead sulfate phosphors.
Claim 25
Dependent Claim
110 words
The process of preparing barium lead sulfate phosphors which comprises preparing an aqueous solution consisting of about 0.24 molar barium chloride, 0.013 molar lead chloride and 0.013 molar hydrochloric acid; preparing a second aqueous solution consisting of about 0.25 molar sodium sulfate; preparing a third aqueous solution consisting of about 0.023 molar sodium sulfate and about 0.5 molar hydrochloric acid; simultaneously adding the first and second solutions at the rate of about 22 ml per minute to about 220 ml of the third solution, vigorously agitated in a 4 liter-capacity beaker, while maintaining the temperature of the mixture at about 80* to 95* C; and, recovering barium lead sulfate phosphor.
Claim 26
Dependent Claim
14 words
The method of forming lanthanide-activated alkaline earth sulfate phosphors as defined in claim 1.
Claim 27
Dependent Claim
81 words
The method of forming lanthanide-activated barium sulfate phosphors in accordance with claim 27 wherein an excess of sulfate ions over the amount required to react with the barium and lanthanide ions is maintained in the solution in which said phosphors are formed, said excess being up to 0.5 molar; and, the rate of addition of the anions and cations to form said phosphor, each, is less than 0.04 mole per liter of solution in which said phosphors are formed per minute.
Claim 28
Dependent Claim
25 words
The method of forming lanthanide-activated barium sulfate phosphors in accordance with claim 28 wherein said excess of sulfate ions is less than about 0.1 molar.
Claim 29
Dependent Claim
43 words
The method of forming lanthanide-activated barium sulfate phosphors in accordance with claim 29 wherein the solution in which said phosphors are formed is an aqueous acidic solution having a pH of less than 0.5, and the reaction is conducted at about 100* C.
Claim 30
Dependent Claim
45 words
The method of forming lanthanide-activated barium sulfate phosphors in accordance with claim 28 wherein an univalent cation is maintained in the solution in which said phosphors are formed throughout the reaction in an amount sufficient to effectively quench chemiluminescence and enhance precipitation of the lanthanide.
Claim 31
Dependent Claim
34 words
The method of forming lanthanide-activated barium sulfate phosphors in accordance with claim 30 wherein an univalent cation is maintained in the solution throughout the reaction in an amount from about 0.02 to 0.2 molar.
Claim 32
Dependent Claim
18 words
The method of preparing lanthanide-activated barium sulfate phosphors as defined in claim 30 wherein the lanthanide-activator is europium.
Claim 33
Dependent Claim
18 words
The method of preparing lanthanide-activated barium sulfate phosphors as defined in claim 32 wherein the lanthanide-activator is europium.
Claim 34
Dependent Claim
29 words
The method of forming lanthanide-activated alkaline earth sulfate phosphors as defined in claim 30 wherein chemiluminescence of said phosphor is removed by heating the phosphor at about 200* C.
Claim 35
Dependent Claim
45 words
The method of forming lanthanide-activated barium sulfate phosphors in accordance with claim 31 wherein the rate of addition of said anions and cations to form said phosphor, each, is less than 0.025 mole per liter of solution in which said phosphors are formed per minute.
Claim 36
Dependent Claim
12 words
The method of forming lead sulfate phosphors as defined in claim 1.
Claim 37
Dependent Claim
53 words
The method of forming lead sulfate phosphors as Defined in claim 37 wherein the lead and sulfate ions to form said phosphor are introduced into the solution in which said phosphors are formed at the rate of less than 0.04 mole per liter of solution in which said phosphors are formed per minute.
Claim 38
Dependent Claim
53 words
The method of forming lead sulfate phosphors as defined in claim 38 wherein said solution in which said phosphors are formed contains, throughout the reaction, an excess of lead ions over the amount required to react with the sulfate ions at any time during the reaction, said excess being less than 0.5 molar.
Claim 39
Dependent Claim
39 words
The method of forming lead sulfate phosphors as defined in claim 38 wherein an univalent cation is present in the solution in which said phosphors are formed in an amount sufficient to effectively enhance the fluorescence of the phosphor.
Claim 40
Dependent Claim
48 words
The method of forming lead sulfate phosphors as defined in claim 40 wherein the univalent cation is selected from ammonium ion and sodium ion, and said univalent cation is present in the solution in which said phosphors are formed at a concentration of from 0.019 to 0.075 molar.
Claim 41
Dependent Claim
44 words
The method of forming lead sulfate phosphors as defined in claim 40 wherein said solution in which said phosphors are formed in an aqueous acidic solution having a pH below 1, and said reaction is conducted at a temperature of at least 50* C.
Claim 42
Dependent Claim
12 words
The method of forming barium fluorochloride phosphor as defined in claim 1.
Claim 43
Dependent Claim
53 words
The method of forming barium fluorochloride phosphor as defined in claim 43 wherein the anions and cations to form said phosphor, each, are introduced into the solution in which said phosphors are formed at the rate of less than 0.04 mole per liter of solution in which said phosphors are formed per minute.
Claim 44
Dependent Claim
53 words
The method of forming barium fluorochloride phosphor as defined in claim 43 wherein the anions and cations to form said phosphor, each, are introduced into the solution in which said phosphors are formed at the rate of less than 0.025 mole per liter of solution in which said phosphors are formed per minute.
Claim 45
Dependent Claim
21 words
The method of increasing the efficiency of barium fluorochloride phosphors prepared in accordance with claim 44 which comprises ripening said phosphors.
Claim 46
Dependent Claim
39 words
The method of increasing the efficiency of barium fluorochloride phosphors as defined in claim 46 wherein said ripening is effected in the solution in which said phosphors are formed, and at a temperature of from 80* to 100* C.
Claim 47
Dependent Claim
12 words
The method of forming calcium tungstate phosphors as defined in claim 1.
Claim 48
Dependent Claim
54 words
The method of forming calcium tungstate phosphors as defined in claim 48 wherein the calcium and tungstate ions to form said phosphor, each, are introduced into the solution in which said phosphors are formed at the rate of less than 0.04 mole per minute per liter of solution in which said phosphors are formed.
Claim 49
Dependent Claim
32 words
The method of forming calcium tungstate phosphors as defined in claim 48 wherein said solution in which said phosphors are formed is an aqueous solution having a pH of at least 7.
Claim 50
Dependent Claim
21 words
The method of increasing the efficiency of calcium tungstate phosphors prepared in accordance with claim 49 which comprises ripening said phosphors.
Claim 51
Dependent Claim
29 words
The method of increasing the efficiency of calcium tungstate phosphors as defined in claim 51 wherein said ripening is effected in the solution in which said phosphors are formed.
Claim 52
Dependent Claim
66 words
The method of forming calcium tungstate phosphors as defined in claim 52 wherein said solution in which said phosphors are formed is maintained at a temperature of about 20 to 50* C during the reaction of the calcium ions with the tungstate ions, and said ripening is conducted in the solution in which said phosphors are formed at a temperature of from 70* to 100* C.
Claim 53
Dependent Claim
33 words
The method of increasing the efficiency of calcium tungstate phosphors as defined in claim 51 wherein said phosphors, after said ripening, are heated to a temperature sufficient to further increase the efficiency thereof.
Claim 54
Dependent Claim
33 words
The method of increasing the efficiency of calcium tungstate phosphors as defined in claim 52 wherein said phosphors, after said ripening, are heated to a temperature sufficient to further increase the efficiency thereof.
Claim 55
Dependent Claim
28 words
The method of increasing the efficiency of calcium tungstate phosphors as defined in claim 55 wherein said phosphors are heated to about 700* C for about one-half hour.
Claim 56
Dependent Claim
30 words
The method of increasing the efficiency of calcium tungstate phosphors prepared in accordance with claim 49 which comprises heating said phosphors to a temperature sufficient to increase the efficiency thereof.
Claim 57
Dependent Claim
28 words
The method of increasing the efficiency of calcium tungstate phosphors as defined in claim 57 wherein said phosphors are heated to about 700* C for about one-half hour.
Claim 58
Dependent Claim
25 words
The method of increasing the efficiency of calcium tungstate phosphors as defined in claim 56 wherein said heating is conducted in the absence of flux.
Claim 59
Dependent Claim
25 words
The method of increasing the efficiency of calcium tungstate phosphors as defined in claim 58 wherein said heating is conducted in the absence of flux.
Claim 60
Dependent Claim
16 words
The method of forming lead carbonate and alkaline earth carbonate phosphors as defined in claim 1.
Claim 61
Dependent Claim
47 words
The method of forming lead carbonate and alkaline earth carbonate phosphors as defined in claim 61 wherein the anions and cations to form said phosphor, each, are introduced into said reaction solution at the rate of less than 0.04 mole per minute per liter of reaction solution.
Claim 62
Dependent Claim
65 words
The method of forming lead carbonate and alkaline earth carbonate phosphors as defined in claim 62 wherein said solution in which said phosphors are formed contains, throughout the reaction, an excess of carbonate ions over that required to react with the cations, in the solution in which said phosphors are formed at any time during the reaction, said excess being up to about 0.1 molar.
Claim 63
Dependent Claim
39 words
The method of forming phosphors of the group consisting of europium-activated barium sulfate, terbium-activated barium sulfate, samarium-activated barium sulfate, gadolinium-activated barium sulfate and cerium-activated barium sulfate as defined in claim 8 wherein said cation is the alkaline earth barium.
Claim 64
Dependent Claim
54 words
The method of forming phosphors as defined in claim 8 wherein said phosphors are selected from the group consisting of barium lead sulfate, lanthanide-activated barium sulfate, lead sulfate, barium bismuth sulfate, barium calcium manganese sulfate, lanthanide-activated barium fluoride, barium fluorochloride, calcium tungstate, lead carbonate, lanthanide-activated barium hydrogen phosphate and the alkaline earth carbonate phosphors.
Claim 65
Independent Claim
201 words
The method of forming inorganic phosphor having an anion and a cation, said phosphor being selected from the group consisting of barium lead sulfate, lanthanide-activated barium sulfate, lead sulfate, barium bismuth sulfate, barium calcium manganese sulfate, lanthanide-activated barium fluoride, barium fluorochloride, calcium tungstate, lead carbonate, lanthanide-activated barium hydrogen phosphate, and the alkaline earth carbonate phosphors, which comprises: a. providing an aqueous solution in which said phosphors are formed adapted to permit said anions and cations to form crystals of said phosphor of at least .5 micron in size; b. introducing anion to form said phosphor into said solution in which said phosphors are formed at the rate of up to 0.1 mole per liter of solution in which said phosphors are formed per minute; c. simultaneously introducing cation to form said phosphor into said solution in which said phosphors are formed at the rate of up to 0.1 mole per liter of solution in which said phosphors are formed per minute; d. maintaining said solution in which said phosphors are formed, throughout the reaction, a concentration of less than 0.5 molar, each of said anions and cations; and, e. Agitating the solution in which said phosphors are formed throughout the reaction.
Claim 66
Dependent Claim
50 words
The method of forming phosphors as defined in claim 66 wherein said anions and said cations, each, are introduced into said solution in which said phosphors are formed from separate aqueous solutions thereof, each of said solutions having a concentration of less than about 0.5 molar anion and cation, respectively.
Claim 67
Dependent Claim
34 words
The method of forming phosphors as defined in claim 67 wherein a plurality of streams of said solutions of anions and said cations are introduced into said solution in which said phosphors are formed.
Claim 68
Dependent Claim
24 words
The method of preparing barium lead sulfate phosphor as defined in claim 23 wherein the reaction is conducted in the absence of nitrate ion.
Claim 69
Dependent Claim
23 words
The method of preparing lead sulfate phosphor as defined in claim 40 wherein the reaction is conducted in the absence of nitrate ion.
Claim 70
Dependent Claim
23 words
The method of preparing barium fluorochloride phosphor as defined in claim 44 wherein the reaction is conducted in the absence of nitrate ion.
Claim 71
Dependent Claim
23 words
The method of preparing lead carbonate phosphor as defined in claim 63 wherein the reaction is conducted in the absence of nitrate ion.
Claim 72
Dependent Claim
24 words
The method of preparing alkaline earth carbonate phosphor as defined in claim 63 wherein the reaction is conducted in the absence of nitrate ion.
Claim 73
Dependent Claim
12 words
The method of forming barium bismuth sulfate in accordance with claim 1.
Claim 74
Dependent Claim
13 words
The method of forming barium calcium manganese sulfate in accordance with claim 1.
Claim 75
Dependent Claim
13 words
The method of forming lanthanide-activated barium hydrogen phosphate in accordance with claim 1.
Claim 76
Dependent Claim
12 words
The method of forming lanthanide-activated barium fluoride in accordance with claim 1.
References Cited (Backward Citations)
GB741324A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1975-06-06 | 1975-12-06 | 1976-06-06 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-06-06 | 1979-12-06 | 1980-06-06 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-06-06 | 1983-12-06 | 1984-06-06 | $7700.00 | Window Closed / Lapsed |