US3586637A - Europium activated barium and strontium borophosphate luminescent material - Google Patents

Europium activated barium and strontium borophosphate luminescent material Download PDF

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Publication number
US3586637A
US3586637A US834285A US3586637DA US3586637A US 3586637 A US3586637 A US 3586637A US 834285 A US834285 A US 834285A US 3586637D A US3586637D A US 3586637DA US 3586637 A US3586637 A US 3586637A
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United States
Prior art keywords
radiation
luminescent material
strontium
luminescent
barium
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Expired - Lifetime
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US834285A
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English (en)
Inventor
George Blasse
Jaap De Vries
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US Philips Corp
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US Philips Corp
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    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09K—MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
    • C09K11/00—Luminescent, e.g. electroluminescent, chemiluminescent materials
    • C09K11/08—Luminescent, e.g. electroluminescent, chemiluminescent materials containing inorganic luminescent materials
    • C09K11/77—Luminescent, e.g. electroluminescent, chemiluminescent materials containing inorganic luminescent materials containing rare earth metals
    • C09K11/7728—Luminescent, e.g. electroluminescent, chemiluminescent materials containing inorganic luminescent materials containing rare earth metals containing europium
    • C09K11/7737—Phosphates
    • C09K11/7738—Phosphates with alkaline earth metals
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09K—MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
    • C09K11/00—Luminescent, e.g. electroluminescent, chemiluminescent materials
    • C09K11/08—Luminescent, e.g. electroluminescent, chemiluminescent materials containing inorganic luminescent materials
    • C09K11/77—Luminescent, e.g. electroluminescent, chemiluminescent materials containing inorganic luminescent materials containing rare earth metals
    • C09K11/7728—Luminescent, e.g. electroluminescent, chemiluminescent materials containing inorganic luminescent materials containing rare earth metals containing europium
    • C09K11/774—Borates

Definitions

  • the invention relates to a novel luminescent material and to a low-pressure mercury vapor lamp employing such a material.
  • a document is copied by irradiating the master and directing the radiation which has been reflected or transmitted to a piece of paper which is sensitive to this radiation and contains substances which can be decomposed by the radiation so that a copy of the master document is obtained possibly after further treatment, for example, fixing.
  • a requirement generally imposed on the reproduction papers to be used is that the substances which are sensitive to radiation are converted as little as possible by normal daylight. This of course facilitates working with these papers and also imposes few requirements on the storage thereof. Since normal daylight contains comparatively little ultraviolet radiation, the best combination is apparently a paper which has a maximum sensitivity below 400 nm. and a radiation source which emits a strong ultraviolet radiation.
  • the master to be copied must transmit or reflect the radiation. It has been found that many documents are made from paper which transmits and/or reflects ultraviolet radiation comparatively poorly. In view of the contradictory requirements for documentcopying machines, a compromise must therefore be made: it is therefore preferred to use light-sensitive papers the maximum sensitivity of which lies between 380 and 440 nm. and a radiation source having a maximum of the emitted radiation between these two values.
  • Document-copying machines generally use as radiation sources mercury vapour discharge lamps including a luminescent layer provided on a support, which layer converts a great part of the ultraviolet radiation produced in the mercury vapour discharge into radiation of longer wavelength.
  • the maximum emitted radiation energy must preferably be in the wavelength range between 380 and 440 nm. This is, for example, the case with the very frequently used substance, calcium tungstate.
  • the conversion efficiency of the ultraviolet radiation of the mercury vapour discharge into radiation between 380 and 440 nm. is however, comparatively small for this substance, because the emission spectrum is very wide and hence much radiation energy is emitted at wavelength outside this range.
  • the absorption spectrum of most light-sensitive papers is considerably narrower than this range. As a result of these two Patented June 22, 1971 ice causes only a comparatively small part of the total radiation energy emitted by the calcium tungstate is efficiently used by the sensitive paper.
  • a further luminescent substance which is very frequently used, is a lead-activated silicate of strontium, barium and magnesium.
  • the emission spectrum of this substance is not very wide when excited by the ultraviolet radiation of a mercury vapour discharge and hence is more suitable for adaptation to the absorption spectrum of a radiation-sensitive paper; the maximum emission of this substance lies, however, at 355 nm. and is therefore less suitable to be transmitted or reflected by the paper of most documents. In spite of this fact, the substance is very frequently used on account of the narrow emission band and the strong radiation.
  • a low-pressure mercury vapour discharge lamp includes a luminescent material provided on a support and is characterized in that this luminescent material is an alkaline earth borate-phosphate activated by bivalent europium and having the following composition.
  • the substances according to the invention have a good temperature dependence, that is to say, their conversion efficiency decreases only slightly as the temperature increases. They are thus very suitable for use in high-power, low-pressure mercury vapour discharge lamps, whose wall temperature assumes a high value during operation.
  • a luminescent material according to the invention consists of a bivalent europium-activated borate-phosphate of barium and/or strontium, wherein the barium and/or strontium may be partly replaced by calcium.
  • the fundamental lattices of the borate-phosphates of the alkaline earth metals barium, strontium and calcium are isomorphous.
  • the pure barium borate-phosphate activated by bivalent europium is preferred because this substance has the highest light output. This substance has its maximum emission at a wavelength of approximately 385 nm.
  • the pure strontium borate-phosphate activated by bivalent europium has its maximum emission at a wavelength of approximately 390 nm.
  • the barium-strontium borate-phosphates according to the invention have their maximum emission at wavelength between the above-mentioned values and a light output which is approximately equal to that of the pure strontium borate-phosphate.
  • FIG. 1 shows a low-pressure mercury vapour discharge lamp which includes an envelope 1. Electrodes 2 and 3 between which the discharge takes place during opera-' 5 limits because otherwise luminescent substances are obtion of the lamp, are provided at the ends of the lamp. tained which are not usable for practice.
  • the envelope 1 by bringing a suspension of the luminescent
  • the material and nitrocellulose in butyl acetate into contact materials according to the present invention it is to be with the inner side of the envelope, whereby a thin layer noted that the substances are only slightly affected by oxiof the suspension is left on the envelope.
  • the nitrocelludation. This is of great importance in the manufacture lose serves as a temporary adhesive.
  • the envelope of the mercury vapour discharge lamps because they are is subjected to a thermal treatment by which the temthen often exposed for a short period to a heat treatment porary adhesive is removed and a satisfactory adhesion in air at a fairly high temperature, for example, 600 C. of the luminescent layer is obtained.
  • curve b shows the spectral energy disbe described with reference to one table, one example tribution of the known calcium tungstate. These curves and one drawing. are shown for comparison both for the spectral distribu- TABLE Location Composition firing mixture in grams max. Rel. emission light Formula BaCO 81-00 CaCO E1120; H3130; (NHOQHPO; (nm.) output Example:
  • a mixture was made of the substances indicated in the table in the quantities indicated for each example in the table. Since the boric acid partly evaporates during the reaction, an excess of H BO of approximately 20% relative to the stoichiometric quantity is always used.
  • the mixture was heated at a temperature between 400 and 600 C. for approximately 4 hours. After cooling of the firing product obtained, it was ground and again heated at a temperature between 800 and 900 C. for 4 hours. In both cases the heat treatment took place in a mixture of nitrogen and hydrogen. The ratio of nitrogen to hydrogen is then not critical, 2. ratio of, for example, 20:1 was found to be quite useable.
  • the hydrogen serves for reducing the trivalent europium to bivalent europium. After cooling subsequent to the second heat treatment the reaction product obtained was ground and sieved, if necessary. The product was then ready for use.
  • the last two columns of the table state the wavelengths of the maximum of the emission band (in nm.) and the relative light-outputs in arbitrary units for the different substances.
  • FIG. 1 diagrammatically shows a low-pressure mercury vapour discharge lamp according to the invention
  • FIG. 2 is a graphic representation of the radiation intensities of a few substances according to the invention, and of two 'known substances as a function of the wavelength;
  • FIG. 3 is a graphic representation of the variation of The maximum intensity of the curve a is fixed at 100.
  • the curves 2., 6, 12 and 13 relate to the materials of Examples 2, 6, 12 and 13 of the table.
  • the luminescent materials according to the invention have higher peak values and a narrower emission range as compared with the known silicate and the known tungstate, while they have a more favourable location of the maximum emission in the spectrum as compared with the known silicate.
  • the curve 2 in the graph of FIG. 3 shows the temperature dependence of the radiation intensity of the material of Example 2.
  • the temperature is plotted in C. on the abscissa.
  • the maximum intensity is fixed at 100.
  • the figure shows that the borate-phosphates according to the invention have a very good temperature dependence.
  • the barium borate-phosphate still shows an intensity of the luminescent radiation at approximately 300 C. which is equal to half the maximum value. It may be noted for comparison that already at 75 C. the intensity of the known calcium tungstate has decreased to half the value at room temperature.
  • the luminescent substances according to the invention may also be excited by electrons. In that case they have the same emission as when excited by ultraviolet radiation.
  • a luminescent material consisting essentially of an alkaline earth bore-phosphate activated by bivalent europium and having the formula (Ba, Sr) Ca Eu BPO wherein 1 1 i 2 05x0.5, and 00033115015 6 2.
  • the luminescent material of claim 1 wherein 5 0.005SP0.05 ROBERT D. EDMONDS, Primary Examiner 4.
  • the luminescent material of claim 2 wherein 0.005SPS0.05

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  • Chemical & Material Sciences (AREA)
  • Inorganic Chemistry (AREA)
  • Engineering & Computer Science (AREA)
  • Materials Engineering (AREA)
  • Organic Chemistry (AREA)
  • Luminescent Compositions (AREA)
US834285A 1968-06-22 1969-06-18 Europium activated barium and strontium borophosphate luminescent material Expired - Lifetime US3586637A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
NL6808846A NL6808846A (enrdf_load_stackoverflow) 1968-06-22 1968-06-22

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US3586637A true US3586637A (en) 1971-06-22

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US834285A Expired - Lifetime US3586637A (en) 1968-06-22 1969-06-18 Europium activated barium and strontium borophosphate luminescent material
US00115787A Expired - Lifetime US3748516A (en) 1968-06-22 1971-02-16 Low-pressure mercury vapour discharge lamp

Family Applications After (1)

Application Number Title Priority Date Filing Date
US00115787A Expired - Lifetime US3748516A (en) 1968-06-22 1971-02-16 Low-pressure mercury vapour discharge lamp

Country Status (9)

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US (2) US3586637A (enrdf_load_stackoverflow)
JP (1) JPS495426B1 (enrdf_load_stackoverflow)
AT (1) AT286450B (enrdf_load_stackoverflow)
BE (1) BE734960A (enrdf_load_stackoverflow)
DE (1) DE1927455B2 (enrdf_load_stackoverflow)
FR (1) FR2011479A1 (enrdf_load_stackoverflow)
GB (1) GB1197279A (enrdf_load_stackoverflow)
NL (1) NL6808846A (enrdf_load_stackoverflow)
SE (1) SE340666B (enrdf_load_stackoverflow)

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3884249A (en) * 1972-10-20 1975-05-20 Gte Sylvania Inc Process for cleaning halophosphate furnaces
US3905912A (en) * 1974-09-25 1975-09-16 Gte Sylvania Inc Rare earth activated hafnium phosphate luminescent materials
US4174294A (en) * 1977-12-20 1979-11-13 Mitsubishi Denki Kabushiki Kaisha Fluorescent material
US4185222A (en) * 1978-01-13 1980-01-22 U.S. Philips Corporation Luminescent bivalent europium-activated barium borophosphate and discharge lamp containing the same
CN103237867A (zh) * 2010-10-26 2013-08-07 发光物质工厂布赖通根有限责任公司 硼磷酸盐磷光体和光源
CN110229668A (zh) * 2019-06-24 2019-09-13 云南大学 一种铕掺杂的橙红色荧光材料及其制备方法与应用

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3973691A (en) * 1974-10-21 1976-08-10 Gte Sylvania Incorporated Fluorescent lamp having improved phosphor coating
JPS5919412B2 (ja) * 1978-01-30 1984-05-07 三菱電機株式会社 けい光ランプ

Family Cites Families (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3205394A (en) * 1960-04-06 1965-09-07 Sylvania Electric Prod Fluorescent lamp having a sio2 coating on the inner surface of the envelope
US3522191A (en) * 1966-12-21 1970-07-28 Owens Illinois Inc Luminophors and method
US3516940A (en) * 1967-12-15 1970-06-23 Sylvania Electric Prod Europium activated bao.mgo.p2o5 phosphors

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3884249A (en) * 1972-10-20 1975-05-20 Gte Sylvania Inc Process for cleaning halophosphate furnaces
US3905912A (en) * 1974-09-25 1975-09-16 Gte Sylvania Inc Rare earth activated hafnium phosphate luminescent materials
US4174294A (en) * 1977-12-20 1979-11-13 Mitsubishi Denki Kabushiki Kaisha Fluorescent material
US4185222A (en) * 1978-01-13 1980-01-22 U.S. Philips Corporation Luminescent bivalent europium-activated barium borophosphate and discharge lamp containing the same
CN103237867A (zh) * 2010-10-26 2013-08-07 发光物质工厂布赖通根有限责任公司 硼磷酸盐磷光体和光源
CN103237867B (zh) * 2010-10-26 2014-11-19 发光物质工厂布赖通根有限责任公司 硼磷酸盐磷光体和光源
CN110229668A (zh) * 2019-06-24 2019-09-13 云南大学 一种铕掺杂的橙红色荧光材料及其制备方法与应用
CN110229668B (zh) * 2019-06-24 2022-02-22 云南大学 一种铕掺杂的橙红色荧光材料及其制备方法与应用

Also Published As

Publication number Publication date
FR2011479A1 (enrdf_load_stackoverflow) 1970-02-27
DE1927455A1 (de) 1970-01-02
AT286450B (de) 1970-12-10
NL6808846A (enrdf_load_stackoverflow) 1969-12-24
US3748516A (en) 1973-07-24
DE1927455B2 (de) 1976-11-25
SE340666B (enrdf_load_stackoverflow) 1971-11-29
GB1197279A (en) 1970-07-01
BE734960A (enrdf_load_stackoverflow) 1969-12-22
JPS495426B1 (enrdf_load_stackoverflow) 1974-02-07

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