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GB2031454A - Fluorescent lamp - Google Patents

Fluorescent lamp Download PDF

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Publication number
GB2031454A
GB2031454A GB7930765A GB7930765A GB2031454A GB 2031454 A GB2031454 A GB 2031454A GB 7930765 A GB7930765 A GB 7930765A GB 7930765 A GB7930765 A GB 7930765A GB 2031454 A GB2031454 A GB 2031454A
Authority
GB
United Kingdom
Prior art keywords
activated
fluorescent lamp
phosphor
emitting phosphor
strontium
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Granted
Application number
GB7930765A
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GB2031454B (en
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Toshiba Corp
Original Assignee
Tokyo Shibaura Electric Co Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Tokyo Shibaura Electric Co Ltd filed Critical Tokyo Shibaura Electric Co Ltd
Publication of GB2031454A publication Critical patent/GB2031454A/en
Application granted granted Critical
Publication of GB2031454B publication Critical patent/GB2031454B/en
Expired legal-status Critical Current

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Classifications

    • CCHEMISTRY; METALLURGY
    • C09DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09KMATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
    • C09K11/00Luminescent, e.g. electroluminescent, chemiluminescent materials
    • C09K11/08Luminescent, e.g. electroluminescent, chemiluminescent materials containing inorganic luminescent materials
    • C09K11/77Luminescent, e.g. electroluminescent, chemiluminescent materials containing inorganic luminescent materials containing rare earth metals
    • C09K11/7728Luminescent, e.g. electroluminescent, chemiluminescent materials containing inorganic luminescent materials containing rare earth metals containing europium
    • C09K11/7737Phosphates
    • C09K11/7738Phosphates with alkaline earth metals
    • C09K11/7739Phosphates with alkaline earth metals with halogens
    • CCHEMISTRY; METALLURGY
    • C09DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09KMATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
    • C09K11/00Luminescent, e.g. electroluminescent, chemiluminescent materials
    • C09K11/08Luminescent, e.g. electroluminescent, chemiluminescent materials containing inorganic luminescent materials
    • C09K11/77Luminescent, e.g. electroluminescent, chemiluminescent materials containing inorganic luminescent materials containing rare earth metals
    • C09K11/7766Luminescent, e.g. electroluminescent, chemiluminescent materials containing inorganic luminescent materials containing rare earth metals containing two or more rare earth metals
    • C09K11/77742Silicates
    • CCHEMISTRY; METALLURGY
    • C09DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09KMATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
    • C09K11/00Luminescent, e.g. electroluminescent, chemiluminescent materials
    • C09K11/08Luminescent, e.g. electroluminescent, chemiluminescent materials containing inorganic luminescent materials
    • C09K11/77Luminescent, e.g. electroluminescent, chemiluminescent materials containing inorganic luminescent materials containing rare earth metals
    • C09K11/7783Luminescent, e.g. electroluminescent, chemiluminescent materials containing inorganic luminescent materials containing rare earth metals containing two or more rare earth metals one of which being europium
    • C09K11/7784Chalcogenides
    • C09K11/7787Oxides
    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01JELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J61/00Gas-discharge or vapour-discharge lamps
    • H01J61/02Details
    • H01J61/38Devices for influencing the colour or wavelength of the light
    • H01J61/42Devices for influencing the colour or wavelength of the light by transforming the wavelength of the light by luminescence
    • H01J61/44Devices characterised by the luminescent material

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  • Chemical & Material Sciences (AREA)
  • Inorganic Chemistry (AREA)
  • Engineering & Computer Science (AREA)
  • Materials Engineering (AREA)
  • Organic Chemistry (AREA)
  • Vessels And Coating Films For Discharge Lamps (AREA)
  • Luminescent Compositions (AREA)

Abstract

A phosphor composition (2) is coated on the inside of the envelope (1) of a fluorescent lamp and comprises a green-emitting phosphor of yttrium silicate activated by cerium and terbium; a red emitting phosphor of yttrium oxide activated by europium, and a blue-emitting phosphor having an emission spectrum with a peak in the wave length range between 450 and 460 nm and a smaller half width than 50 nm. The blue-emitting phosphor is preferably a strontium chlorophosphate activated by divalent europium with the strontium partly replaced by calcium and/or barium. The yttrium silicate may be partly replaced by zinc silicate activated by Mn or calcium halophosphate activated by Sb + Mn. <IMAGE>

Description

SPECIFICATION Fluorescent lamp This invention relates to a fluorescent lamp whose color temperature ranges between 2800 and 7000 k, and which ensures high luminous efficacy and satisfactory color rendering property.
A fluorescent lamp has been applied as a general source of illumination light for long years.
Prominent progress has been achieved in respect of both luminous efficacy and color rendering property through improvements on the construction of a fluorescent lamp and development of new phosphor materials. Particularly calcium halo phospate phosphor activated by manganese and antimony which provides not only high luminous efficacy and a certain degree of color rendering property, but also can be manufactured at low cost is now used with almost all types of fluorescent lamp for general illumination purpose. Therefore, a fluorescent lamp using the above-mentioned calcium halophosphate phosphor represents a highly efficient type.
As described above, however, a fluorescent lamp provided with the calcium halophosphate phosphor activated by Mn and Sb still fails to ensure fully satisfactory color rendering property.
To date, numerous improvements have been attempted to eliminate said drawback. A typical improvement may be represented by a phosphor composition set forth in Japanese Patent Publication No. 32759/1975. This proposed composition is intended to improve the color rendering property of the ordinary fluorescent lamp by replenishing the insufficient radiation energy of the red range of the above-mentioned calcium halophosphate phosphor. It has been found, however, that the improvement in the color rendering property is accompanied by a great sacrifice of the high luminous efficacy of a fluorescent lamp using the calcium halophosphate phosphor activated by Mn and Sb. Therefore, the phosphor composition proposed in the aforesaid Japanese Patent Publication is restricted in application.
Recently, a fluorescent lamp of three spectral peak system has been proposed, which uses a phosphor composition exhibiting an emission spectral distribution having peaks of narrow half width in three wavelength regions, i.e., a blue region around 450 nm, a green region around 540 nm and a red region around 610 nm. A lamp of this type seems to permit exhibiting both high luminous efficacy and high color rendering property and, thus, attracts keen attentions in this field. Phosphor compositions used in a lamp of this type include a mixture of Eu2±activated strontium chloroapatite phosphor, Mn2±activated zinc silicate phosphor and Eu3±activated yttrium oxide phosphor as disclosed in, for example, Japanese Patent Application Disclosure No.
49-100877.
However, the Eu2±activated strontium chloroapatite phosphor causes the luminous efficacy of a fluorescent lamp to decrease. Certainly, the Mn2±activated zinc silicate phosphor is effective for improving the luminous efficacy but is known to indicate a noticeable decrease in said luminous efficacy while a fluorescent lamp is applied, and moreover low application resistance.
It is therefore easily inferred that a fluorescent lamp using a mixture of the above-mentioned three phosphors as a light-emitting layer gives rise to changes in the color of emitted light as well as to a decreased luminous efficacy during application.
It is accordingly the object of this invention to provide a fluorescent lamp of high luminous efficacy and satisfactory color rendering property by application of phosphors free from drawbacks accompanying the prior art phosphors.
According to the invention, there is provided a fluorescent lamp which comprises a vacuumtight envelope provided with electrodes between which discharge takes place during the operation of said fluorescent lamp and coated on the inside with a phosphor composition comprising: a green-emitting phosphor consisting essentially of yttrium silicate activated by cerium and terbium; a red-emitting phosphor consisting essentially of yttrium oxide activated by europium; and a blue-emitting phosphor having an emission spectrum with a peak in the wavelength range between 450 and 460 nm and smaller half width than 50 nm.
This invention can be more fully understood from the following detailed description when taken in conjunction with the accompanying drawings, in which: Figure 1 is a graph showing a spectral energy distribution of the radiation from a fluorescent lamp according to one embodiment of this invention; Figure 2 is a graph showing an emission spectrum of a typical phosphor used in a fluorescent lamp of this invention; Figure 3 is a color diagram in which is indicated the position of the light emitted from a fluorescent lamp of this invention; Figure 4 is a graph showing a spectral energy distribution of the radiation from a fluorescent lamp according to another embodiment of this invention; Figure 5 is a graph showing a spectral energy distribution of a calcium halophosphate phosphor activated by antimony and manganese; and Figure 6 is a cross sectional view exemplifying the construction of a fluorescent lamp of this invention.
Fig. 1 shows a spectral energy distribution of the radiation from a fluorescent lamp of this invention using a mixture of a green-emitting phosphor, a red-emitting phosphor and a blueemitting phosphor. The lamp mentioned exhibits a luminous efficacy of 82 lumen/watt and an average color rendering index Ra of 84 under a color temperature of 5000 K. This invention is based on the finding that the color rendering properly can be markedly improved by combining the three spectral energy peaks shown in Fig. 1 with the luminous efficacy kept at a sufficiently high level.
In the fluorescent lamp of this invention, three kinds of narrow band emission of the phosphor composition are combined so as to generate a white light. The color of a substance illuminated by the white light is the same as that of the substance under natural light. It is important to note that the phosphor composition used in this invention contains a blue-emitting phosphor having an emission spectrum with a peak in the wavelength range between 450 and 460 nm and a half width smaller than 50 nm. The blue-emitting phosphor is provided by, for example, strontium-calcium chloroapatite activated by divalent europium phosphor, Sir,~, Eu, (to4)2.
yCaCI2 (0.005 ~ x ;;;; 0.20, 0.5 y 0.5~y~ 5.0). This phosphor exhibits an emission spectral distribu- tion having a peak around 453 nm and a half width of about 42 nm.
The green-emitting phosphor contained in the phosphor composition used in this invention is provided by yttrium silicate activated by cerium and terbium. However, this phosphor, which is very costly, may be partly replaced by a filler of another cheap phosphor such as zinc silicate activated by manganese, calcium halophorphate activated by antimony and manganese, or a mixture thereof. The amount of the filler should preferably be not larger than 40% by weight.
The phosphor composition used in this invention further contains a red-emitting phosphor of yttrium oxide activated by trivalent europium.
Fig. 2 shows the emission spectra of the three phosphors contained in the phosphor composition used in this invention. In the drawing curve 1 denotes the emission spectrum of strontium-calcium chloroapatite activated by divalent eurupium, curve 2 represents the emission spectrum of yttrium silicate activated by cerium and terbium, and curve 3 indicates the emission spectrum of yttrium oxide activated by trivalent europium.
Fig. 3 shows a color diagram of the lights emitted from the fluorescent lamps of the Examples described later. In Fig. 3, numerals 1 to 4 represent Examples 1 to 4, respectively.
As shown in Fig. 6, a fluorescent lamp of this invention comprises a glass tube 1, a phosphor composition film 2 coated on the inner surface of the glass tube 1, mouthpieces 3 and 4 mounted to the ends of the glass tube 1, and electrodes 5 and 6 disposed within the glass tube 1. These electrodes are connected to an exterior power source (not shown) via mouthpiece pins 7 and 8 fixed to the mouthpieces 3 and 4, respectively.
Described in the following are Examples of this invention.
Example 1 A fluorescent lamp of 40W was produced by an ordinary method, using a phosphor composition prepared by mixing a blue-emitting phosphor of strontium-calcium chloro-apatite activated by divalent europium, a green-emitting phosphor of yttrium silicate activated by cerium and terbium and a red-emitting phosphor of yttrium oxide activated by trivalent europium such that the mixture was enabled to emit light of chromaticity at point 1 in the color diagram of Fig.
3. Table 1 shows the properties of the light emitted from the fluorescent lamp.
TABLE 1 Phosphor composi- Color Chromaticity Luminous tion (% by weight) temperature coordinates efficacy Ra blue green red x = 0.410 3500 3500 K 85 Im/W 85 11 65 24 y=0.405 Example 2 A fluorescent lamp of 40 W was produced as in Example 1, except that the phosphor composition used was prepared by mixing the three phosphors such that the mixture was enabled to emit light of chromaticity at point 2 in the color diagram of Fig. 3. Table 2 shows the properties of the light emitted from the lamp.
TABLE 2 Phosphor composi- Color Chromaticity Luminous tion (% by weight) temperature coordinates efficacy Ra blue green red x = 0.375 4200 4200 K 83 Im/W 84 15 64 21 y = 0.384 Example 3 A fluorescent lamp of 40W was produced as in Example 1, except that the phosphor composition used was prepared by mixing the three phosphors such that the mixture was enabled to emit light of chromaticity at point 3 in the color diagram of Fig. 3. Table 3 shows the properties of the light emitted from the lamp.
TABLE 3 Phosphor composi- Color Chromaticity Luminous tion (% by weight) temperature coordinates efficacy Ra blue green red x = 0.346 - 5000 K 82 lm/W 84 19 63 18 y = 0.363 Example 4 A fluorescent lamp of 40W was produced as In Example 1, except that the phosphor composition used was prepared by mixing the three phosphors such that the mixture was enabled to emit light of chromaticity of point 4 in the color diagram of Fig. 3. Table 4 shows the properties of the light emitted from the lamp.
TABLE 4 Phosphor composi- Color Chromaticity Luminous tion (% by weight) temperature coordinates efficacy Ra blue green red x = 0.312 6500k 80 80 23 62 15 y = 0.332 Example 5 Fluorescent lamps of 40W were produced as in Example 1, except that the phosphor compositions used were prepared by substituting calcium halophosphate activated by antimony and manganese for part of the green-emitting phosphor of yttrium silicate activated by cerium and terbium. Table 5 shows the properties of the lights emitted from the lamps.
TABLE 5 Color Amount of substitution Luminous temperature (% by weight) efficacy Ra 0 85.0 85.0 3500 K 10 84.3 85.1 + 0.005 uV 20 83.6 84.9 30 83.0 84.3 0 83.0 84.0 4200 K 10 82.4 83.7 +0.005uV 20 81.8 83.2 30 81.1 82.4 0 82.0 84.0 5000 K 10 81.4 83.6 +0.005uV 20 81.2 82.9 30 80.1 82.1 Incidentally, the amount of substitution indicated in Table 5 denotes the amount of calcium halophosphate activated by antimony and manganese relative to the amount of yttrium silicate activated by cerium and terbium.
Table 5 clearly shows that the overall performance of the fluorescent lamp is scarcely affected if a filler of calcium halohosphate activated by antimony and manganese is substituted for part of the green-emitting phosphor of yttrium silicate activated by cerium and terbium, though the substitution brings about slight decreases in average color rendering index Ra and luminous efficacy. In other words, the substitution permits producing a fluorescent lamp of acceptable luminous efficacy and color rendering property at a low cost.
Incidentally, a similar result was obtained where zinc silicate activated by manganese or a mixture of a zinc silicate activated by manganese and calcium halophosphate activated by antimony and manganese was used as the filler.
Fig 4 shows the spectral energy distribution of the radiation from the fluorescent lamp for the case of 5000 K + 0.005 uV of color temperature and 20% by weight of the filler substitution shown in Table 5. Further, Fig. 5 shows the spectral energy distribution of calcium halophosphate activated by antimony and manganese.
As clearly seen from Examples 1 to 5, this invention provides a fluorescent lamp having such a high luminous efficacy as at least 80 Im/W and such a high avarage color rendering index Ra as at least 80 over a wide range of color temperatures.
In this invention, strontium-calcium chloroapatite activated by divalent europium used as the blue-emitting phosphor may be replaced by strontium-calcium-barium chloroapatite activated by divalent europium or strontium-barium chloroapatite activated by divalent europium, with substantially the same effects.

Claims (6)

1. A fluorescent lamp which comprises a vacuum-tight envelope provided with electrodes between which discharge takes place during the operation of said fluorescent lamp and coated on the inside with a phosphor composition comprising: a green-emitting phosphor consisting essentially of yttrium silicate activated by cerium and terbium; a red-emitting phosphor consisting essentially of yttrium oxide activated by europium; and a blue-emitting phosphor having an emission spectrum with a peak in the wave length range between 450 and 460 nm and a smaller half width than 50 nm.
2. The fluorescent lamp according to claim 1, wherein the yttrium siliate activated by cerium and terbium is partly replaced by at least one filler selected from the group consisting of zinc silicate activated by manganese and calcium halophosphate activated by antimony and manganese.
3. The fluorescent lamp according to claim 2, wherein the amount of filler is not larger than 40% by weight based on the amount of the yttrium silicate activated by cerium and terbium.
4. The fluorescent lamp according to claim 1 or 2, wherein the blue-emitting phosphor is selected from the group consisting of strontium-calcium chloroapatite activated by divalent europium, strontium-barium chloroapatite activated by divalent europium and strontium-calciumbarium chloroapatite activated by divalent europium.
5. The fluorescent lamp according to claim 4, wherein the blue-emitting phosphor is strontium-calcium chloroapatite activated by divalent europium.
6. A fluorescent lamp, substantially as hereinbefore described with reference to the Examples.
GB7930765A 1978-09-05 1979-09-05 Fluorescent lamp Expired GB2031454B (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP53108081A JPS5821380B2 (en) 1978-09-05 1978-09-05 fluorescent lamp

Publications (2)

Publication Number Publication Date
GB2031454A true GB2031454A (en) 1980-04-23
GB2031454B GB2031454B (en) 1982-08-25

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ID=14475381

Family Applications (1)

Application Number Title Priority Date Filing Date
GB7930765A Expired GB2031454B (en) 1978-09-05 1979-09-05 Fluorescent lamp

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JP (1) JPS5821380B2 (en)
DE (1) DE2935711C2 (en)
FR (1) FR2435813A1 (en)
GB (1) GB2031454B (en)
PL (1) PL132523B1 (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2002050870A1 (en) * 2000-12-18 2002-06-27 Koninklijke Philips Electronics N.V. Fluorescent colortone lamp with reduced mercury

Families Citing this family (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5743350A (en) * 1980-08-29 1982-03-11 Mitsubishi Electric Corp Fluorescent lamp
JPS57207678A (en) * 1981-06-18 1982-12-20 Toshiba Corp Fluorescent lamp
JPS5920378A (en) * 1982-07-26 1984-02-02 Mitsubishi Electric Corp Fluophor and its use in low-pressure mercury vapor luminescent lamp
JP3124920B2 (en) * 1996-02-09 2001-01-15 スタンレー電気株式会社 Method for blending three-wavelength phosphor and three-wavelength fluorescent lamp using phosphor of the blending method
JP3601775B2 (en) * 1999-12-27 2004-12-15 ハリソン東芝ライティング株式会社 Backlight device and liquid crystal display device
CN104560008B (en) * 2014-12-16 2016-09-28 江门市赛宁灯饰有限公司 A kind of electrodeless lamp powder batching compositions

Family Cites Families (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
NL6811326A (en) * 1968-08-09 1970-02-11
NL164697C (en) * 1973-10-05 1981-01-15 Philips Nv LOW-PRESSURE MERCURY DISCHARGE LAMP.
NZ180650A (en) 1975-06-20 1978-11-13 Gulf Oil Corp Blasting cartidge
JPS52108674A (en) * 1976-03-10 1977-09-12 Toshiba Corp Fluorescent lamp
JPS5314983A (en) * 1976-07-28 1978-02-10 Toshiba Corp High coloring fluorescent lamp
JPS5323175A (en) * 1976-08-16 1978-03-03 Toshiba Corp Fluorescent lamp
JPS5347178A (en) * 1976-10-13 1978-04-27 Toshiba Corp Fluorescent lamp
JPS5348380A (en) * 1976-10-14 1978-05-01 Toshiba Corp Fluorescent lamp
JPH05310087A (en) * 1992-05-08 1993-11-22 Pioneer Electron Corp On-vehicle control system

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2002050870A1 (en) * 2000-12-18 2002-06-27 Koninklijke Philips Electronics N.V. Fluorescent colortone lamp with reduced mercury

Also Published As

Publication number Publication date
PL218118A1 (en) 1980-07-28
GB2031454B (en) 1982-08-25
FR2435813B1 (en) 1983-01-21
JPS5821380B2 (en) 1983-04-28
FR2435813A1 (en) 1980-04-04
DE2935711A1 (en) 1980-03-06
PL132523B1 (en) 1985-03-30
JPS5535422A (en) 1980-03-12
DE2935711C2 (en) 1983-12-15

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746 Register noted 'licences of right' (sect. 46/1977)
PCNP Patent ceased through non-payment of renewal fee