US3857054A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Discharge device and method for generating near infrared radiations
Assignee: Philips North America LLC
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Filing: 1973-07-11
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Granted: 1974-12-24
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Expires: 1993-07-11
Abstract
Abstract To generate near infrared radiations while minimizing the presence of visible radiations, there is irradiated with short wavelength ultraviolet radiations a phosphor consisting essentially of an LiAlO2 matrix activated by from 0.001 to 0.02 gram atom of iron per gram mole of matrix. Preferably the phosphor is incorporated as a coating for an otherwise conventional fluorescent lamp. For best output the phosphor is initially prepared in accordance with conventional techniques by solid-state reaction of the phosphor constituents. Thereafter, the phosphor is fluxed by mixing lithium carbonate therewith, with the gram atoms of lithium in the added carbonate being from 1 to 15 percent of the gram atoms of lithium in the matrix of the mixed phosphor. This mixture is then fired, which increases the output of the phosphor and also its particle size, and residual flux is then removed by leaching in a dilute acidic solution. To insure that all residual unreacted flux is removed, a small amount of aluminum oxide, or aluminum compound which will convert to the oxide on firing, is added to the fluxed material and the mixture refired.
Inventors
- 👤 W Lehmann
- 👤 A Wachtel
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 00:33
CPC Classifications
H; H01; H01J; H01J61/00; H01J61/02; H01J61/38; H01J61/42; H01J61/44; C; C09; C09K; C09K11/00; C09K11/08; C09K11/64; C09K11/646
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
64 words
THE METHOD OF CONVERTING SHORT WAVELENGTH ULTRAVIOLET RADIATIONS INTO NEAR INFRARED RADIATIONS WHILE MINIMIZING THE GENERATION OF VISIBLE RADIATIONS, WHICH METHOD COMPRISES, IRRADIATING WITH SHORT WAVELENGTH ULTRAVIOLET RADIATIONS A PHOSPHOR CONSISTING ESSENTIALLY OF AN LIALO2 MATRIX ACTIVATED BY FROM 0.001 TO 0.02 GRAM ATOM OF IRON PER GRAM MOLE OF SAID MATRIX TO PROVIDE INFRA-RED RADIATIONS HAVING AN EMISSION PEAKED AT APPROXIMATELY 740 N.M.
Claim 2
Independent Claim
64 words
THE METHOD OF CONVERTING SHORT WAVELENGTH ULTRAVIOLET RADIATIONS INTO NEAR INFRARED RADIATIONS WHILE MINIMIZING THE GENERATION OF VISIBLE RADIATIONS, WHICH METHOD COMPRISES, IRRADIATING WITH SHORT WAVELENGTH ULTRAVIOLET RADIATIONS A PHOSPHOR CONSISTING ESSENTIALLY OF AN LIALO2 MATRIX ACTIVATED BY FROM 0.001 TO 0.02 GRAM ATOM OF IRON PER GRAM MOLE OF SAID MATRIX TO PROVIDE INFRA-RED RADIATIONS HAVING AN EMISSION PEAKED AT APPROXIMATELY 740 N.M.
Claim 3
Dependent Claim
29 words
The method as specified in claim 1, wherein said iron activator is present in an amount of about 0.003 to 0.01 gram atom per gram mole of said matrix.
Claim 4
Dependent Claim
42 words
The method as specified in claim 1, wherein said short wavelength ultraviolet radiations are generated by a low-pressure positive-column mercury discharge contained within an elongated radiation-transmitting envelope, and said phosphor is carried as a layer on the interior surface of said envelope.
Claim 5
Dependent Claim
28 words
The method as specified in claim 3, wherein said iron activator is present in amount of about 0.003 to 0.01 gram atom per gram mole of said matrix.
Claim 6
Dependent Claim
95 words
A near-infrared-generating fluorescent discharge device comprising: a sealed elongated radiation-transmitting envelope, a discharge-sustaining filling comprising mercury and inert ionizable starting gas contained within said envelope, electrodes operatively positioned proximate the ends of said envelope and operable to sustain therebetween a low-pressure positive-column mercury discharge, and a phosphor carried as a layer on the interior surface of said envelope and consisting essentially of a LiAlO2 matrix activated by from 0.001 to 0.02 gram atom of iron per gram mole of said matrix, and said discharge device having an infra-red emission which peaks at approximately 740 n.m.
Claim 7
Dependent Claim
95 words
A near-infrared-generating fluorescent discharge device comprising: a sealed elongated radiation-transmitting envelope, a discharge-sustaining filling comprising mercury and inert ionizable starting gas contained within said envelope, electrodes operatively positioned proximate the ends of said envelope and operable to sustain therebetween a low-pressure positive-column mercury discharge, and a phosphor carried as a layer on the interior surface of said envelope and consisting essentially of a LiAlO2 matrix activated by from 0.001 to 0.02 gram atom of iron per gram mole of said matrix, and said discharge device having an infra-red emission which peaks at approximately 740 n.m.
Claim 8
Dependent Claim
28 words
The device as specified in claim 5, wherein said iron activator is present in amount of from 0.003 to 0.01 gram atom per gram mole of said matrix.
Claim 9
Independent Claim
130 words
The method of enhancing the fluorescent response of near-infrared-emitting phosphor having a matrix consisting essentially of LiAlO2 and activated by iron in amount of from 0.001 to 0.02 gram atom per gram mole of said matrix, which method comprises: thoroughly mixing lithium carbonate flux with the prepared finely divided phosphor, with the gram atoms of lithium in said lithium carbonate flux being from 1 to 15 percent of the gram atoms of lithium in the matrix of said mixed phosphor, firing the mixture at a temperature of from about 1,200*C to about 1,300*C for a period of at least about 1 hour, cooling the fired materiAl, and thereafter leaching said fired material in a dilute acidic solution whereby the phosphor infra-red emission which peaks at approximately 740 n.m. is enhanced.
Claim 10
Independent Claim
130 words
The method of enhancing the fluorescent response of near-infrared-emitting phosphor having a matrix consisting essentially of LiAlO2 and activated by iron in amount of from 0.001 to 0.02 gram atom per gram mole of said matrix, which method comprises: thoroughly mixing lithium carbonate flux with the prepared finely divided phosphor, with the gram atoms of lithium in said lithium carbonate flux being from 1 to 15 percent of the gram atoms of lithium in the matrix of said mixed phosphor, firing the mixture at a temperature of from about 1,200*C to about 1,300*C for a period of at least about 1 hour, cooling the fired materiAl, and thereafter leaching said fired material in a dilute acidic solution whereby the phosphor infra-red emission which peaks at approximately 740 n.m. is enhanced.
Claim 11
Dependent Claim
65 words
The method as specified in claim 7, wherein said phosphor after leaching has thoroughly mixed therewith a small amount of aluminum oxide or aluminum compound which will convert to the oxide on firing, and firing said mixture at from about 1,200*C to about 1,300*C for at least one hour to react the added aluminum compound with any excess flux which may remain in said phosphor.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-12-23 | 1978-06-24 | 1978-12-24 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-12-23 | 1982-06-24 | 1982-12-24 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-12-23 | 1986-06-24 | 1986-12-24 | $7700.00 | Window Closed / Lapsed |