JP2010215773A - Fluorescent body and fluorescent lamp - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fluorescent body capable of generating fluorescence at high light-emission intensity without containing an expensive and rare earth element, and to provide a fluorescent lamp using the fluorescent body, both at low cost. <P>SOLUTION: The fluorescent body is represented by formula: M1<SB>x</SB>(Sn<SB>l-y</SB>Ti<SB>y</SB>)<SB>2</SB>M2<SB>z</SB>M3<SB>c</SB>O<SB>r</SB>(wherein M1 is either Ca or Na, M2 is either Al or Si, M3 is a transition element of any of Zr, Hf, Nb, and Ta, x is a number satisfying 1.5≤x≤2.5, y is a number satisfying 0.01<y<0.2, z is a number satisfying 1.5≤z≤2.5, r is a number satisfying 8≤x≤10, and c is a number satisfying 0≤c≤2). Further, the fluorescent lamp has a light transmission pipe, and an electrode for generating discharge and a fluorescent body layer inside the light transmission pipe. In the fluorescent lamp, mercury and a discharge medium are filled in the light transmission pipe. The fluorescent body layer contains the fluorescent body. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a phosphor and a fluorescent lamp that are manufactured at a low cost while having high light emission intensity, and are used for general illumination, liquid crystal backlights, and the like.

  In general, a fluorescent lamp is used as a light source used for a backlight of a liquid crystal panel, general illumination, or the like. In these fluorescent lamps, as shown in Patent Documents 1 to 3, in many cases, phosphors containing expensive rare earth elements such as europium, terbium, yttrium and lanthanum are used. Disadvantageous.

  In addition, Japan is scarce in the resources of rare earth metal elements, and therefore, research on techniques for recovering and recycling rare earth elements used in fluorescent lamps and the like has been actively conducted. Under such circumstances, from the viewpoint of environment and resources, there is a strong demand for phosphors and fluorescent lamps that have sufficient emission intensity and the like as usual fluorescent lamps without using rare earth elements.

  On the other hand, a phosphor containing a tin (Sn) element is known as a phosphor containing no rare earth. For example, Patent Document 4 discloses a phosphor containing a tin (Sn) element. However, when a rare earth element is not used, there are many cases where the emission intensity is inferior, and a phosphor having a high emission intensity without containing a rare earth element is desired.

JP 2004-189997 A JP 2005-239985 A JP 2005-298721 A JP 2009-001760 A

  The present invention has been made in view of the above circumstances, and a phosphor capable of generating fluorescence with high emission intensity without containing an expensive and rare rare earth element, and a fluorescent lamp using the phosphor can be produced at low cost. The purpose is to provide.

In order to achieve the above object, the phosphor according to the first aspect of the present invention comprises:
General _{formula: M1 x (Sn l-y} Ti y) 2 M2 z M3 c O r
(In the formula, M1 is either Ca or Na. M2 is either Al or Si. M3 is a transition element of at least one of Zr, Hf, Nb, and Ta. X is 1.5. ≦ x ≦ 2.5, y is 0.01 <y <0.2, z is 1.5 ≦ z ≦ 2.5, r is 8 ≦ x ≦ 10, and c is a number that satisfies 0 ≦ c ≦ 2. It is characterized by being expressed by

  The fluorescent lamp according to the second aspect of the present invention includes a light-transmitting tube, an electrode for generating a discharge and a phosphor layer inside the light-transmitting tube, and mercury and a discharge medium in the light-transmitting tube. A fluorescent lamp enclosed in a fluorescent lamp, wherein the phosphor layer includes the phosphor according to the first aspect.

  According to the present invention, a phosphor that does not contain an expensive and rare rare earth element and has high emission intensity and can be manufactured at low cost, and by using the phosphor, it has sufficient emission intensity and is low in cost. A manufacturable fluorescent lamp can be provided.

It is a figure showing the emission spectrum of the fluorescent substance produced in Example 1 in this embodiment. In the fluorescent substance obtained by this embodiment, it is a figure showing the titanium content dependence of the light emission peak intensity. Phosphor _Ca 2 _(Sn, Ti) obtained in Example of the present embodiment the powder 2 _Al 2 _{O 9} is a diagram showing the result of measurement by X-ray diffraction.

Hereinafter, the present invention will be described in detail.
[Phosphor]
The phosphor of the present invention has a general formula of M1 _x (Sn _1-y Ti _y ) ₂ M2 _z M3 _c O _r (wherein M1 is either Ca or Na. M2 is either Al or Si) M3 is a transition element of any one of Zr, Hf, Nb, and Ta, x is 1.5 ≦ x ≦ 2.5, y is 0.01 <y <0.2, and z is 1.5. ≦ z ≦ 2.5, r is a number satisfying 8 ≦ x ≦ 10, and c is a number satisfying 0 ≦ c ≦ 2.

  As described above, the phosphor of the present invention does not contain an expensive rare earth element, and contains tin element (Sn) and titanium element (Ti) in the relationship represented by the above-described general formula, so that it is advantageous in terms of cost. And a sufficient amount of light emission intensity is obtained by containing a predetermined amount of titanium element (Ti).

  In the general formula of the phosphor, it is preferable that M1 is Ca, M2 is Al, and c is 0 in that sufficient emission intensity is obtained. More preferably, r is 9.

The crystal structure of the phosphor is preferably an orthorhombic crystal system and the space group is Pbcn. Such a crystal structure has a two-dimensional crystal structure in which the sites where Sn / Ti enters are partitioned by M2-O ₄ tetrahedral chains, and energy transfer between luminescent atoms can be suitably suppressed. effective.

Although there is no restriction | limiting in particular as a manufacturing method of the said fluorescent substance, For example, the following methods etc. are mentioned. First, CaCO ₃ , SnO ₂ , SiO ₂ , TiO _2, etc. are used as raw materials, and SnO ₂ and SiO ₂ are fired at a predetermined temperature (for example, about 1000 ° C.) for a predetermined time (for example, about 6 hours), while CaCO ₃ and TiO ₂ are calcined at a predetermined temperature (for example, about 200 ° C.) for a predetermined time (for example, about 3 hours), weighed so that the elements have a predetermined molar ratio, and after dry mixing, a predetermined pressure (for example, , About 50 MPa) and pressure-molded into a pellet form. Thereafter, the phosphor is obtained as powder by firing and pulverizing at a predetermined temperature (for example, about 1300 to 1400 ° C.) for a predetermined time (for example, 12 hours) using an electric furnace.

Although there is no restriction | limiting in particular as a particle size of the said fluorescent substance, 1 micrometer-20 micrometers are preferable at a particle size, and 2 micrometers-8 micrometers are more preferable.
When the particle size is smaller than 1 μm, the emission intensity may be reduced or aggregates of the phosphor may be formed. On the other hand, when the particle size exceeds 20 μm, the uniform dispersibility in the phosphor may be deteriorated, Color unevenness may occur when used in combination with a phosphor.

  Here, the particle diameter is the central particle diameter (D50) of the phosphor, and can be measured by a laser diffraction method using, for example, a laser diffraction particle size distribution measuring apparatus.

  The phosphor of the present invention described above is manufactured at low cost and has high emission intensity. Therefore, as described below, by using it for the fluorescent lamp of the present invention, it is possible to manufacture at a low cost while exhibiting high emission intensity as compared with a normal fluorescent lamp.

[Fluorescent lamp]
The fluorescent lamp of the present invention includes a light-transmitting tube, and an electrode and a phosphor layer inside the light-transmitting tube, and has other configurations as necessary. The phosphor layer contains the phosphor of the present invention and, if necessary, other components. In the fluorescent lamp of the present invention, mercury and a discharge medium are enclosed in the light-transmitting tube, and other components are included as necessary.

<Translucent tube>
The material of the layer forming the light-transmitting tube is not particularly limited as long as it is a material that transmits visible light, and glass or the like used in a normal fluorescent lamp is preferably used from the viewpoint of ease of processing. The components of the glass is not particularly limited, such as in terms of, not absorb visible light, to SiO 2 is generally of the glass _{component, Al 2 O 3, B 2} O 3, and the like as a main component All common components are preferred. In addition, components such as Na ₂ O, Li ₂ O, K ₂ O, MgO, CaO, SrO, and BaO may be appropriately included depending on the purpose and application.

  The shape of the light-transmitting tube is not particularly limited, and may be any shape such as a curved shape, an annular shape, and a bulb shape, in addition to a straight tube shape having a circular or elliptical cross section. .

<Electrode>
A pair of electrodes is provided inside the translucent tube to generate a discharge for radiating ultraviolet rays from mercury atoms. The electrode is not particularly limited, and may be any type of electrode such as a cold cathode or an external electrode.

When the electrode is a cold cathode, for example, a cup-shaped electrode formed of nickel, molybdenum or the like is used. Such cup-shaped electrodes are preferably used with their openings facing each other and arranged at both ends of the light-transmitting tube.
When the electrode is an external electrode, for example, an electrode made of an aluminum foil, iron, nickel alloy, or the like is used. Such electrodes can be provided, for example, on the outer peripheral surfaces of both end portions of the light-transmitting tube via a silicon resin conductive adhesive or solder containing metal particles or the like.

For the purpose of improving the dark starting characteristics of the fluorescent lamp, it is preferable to provide an electron emitting substance or the like on the surface of the electrode or in the vicinity thereof as necessary.
The electron emitting material is preferably formed of an ionic crystal material. The ionic crystal substance is made of a crystal in which anions and cations are aggregated mainly by electrostatic attraction. The anion of the ionic crystal substance emits secondary electrons in the fluorescent lamp, so that the starting characteristics of the fluorescent lamp are improved.

  Examples of the ionic crystal substances include sulfates, halogenates such as hydrochlorides, fluorides, odorates and iodides, inorganic acid salts such as nitrates and carbonates, and organic acids such as carboxylic acids. Examples thereof include ionic crystal substances containing anions such as acid salts. More specifically, sulfates such as potassium sulfate, sodium sulfate, calcium sulfate, magnesium sulfate, barium sulfate and iron sulfate, halides such as calcium fluoride, magnesium fluoride, calcium chloride and magnesium chloride, calcium carboxylate In addition to carboxylates such as magnesium carboxylate, calcium oxide, magnesium oxide, barium oxide, lanthanum oxide, lanthanum hydroxide and the like can be mentioned. These may be used alone or in combination of two or more.

  In order to form the electron emission material with the ionic crystal material, for example, a coating solution containing the ionic crystal material is prepared, and this is applied to the inner surface of the light-transmitting tube in the vicinity of the electrode or the electrode surface and provided as a coating film. be able to.

<Phosphor layer>
As described above, the phosphor layer is a layer provided inside the translucent tube and includes at least the phosphor of the present invention.

  The phosphor layer may be directly formed on the light-transmitting tube layer (glass layer or the like). As described later, the protective layer (low refractive index) is formed on the light-transmitting tube layer (inside the light-transmitting tube). A protective layer or the like) may be provided and formed on the protective layer.

  The thickness of the fluorescent layer is not particularly limited as long as the visible light transmittance is not affected, but is preferably 3 μm to 50 μm, and more preferably 5 μm to 30 μm. When the thickness exceeds 50 μm, the phosphor layer film may be easily peeled off. On the other hand, if the thickness is less than 3 μm, the phosphor layer is transparent, and sufficient light emission may not be obtained.

The phosphor layer includes the phosphor of the present invention as described above, and includes other components as necessary.
-Phosphor of the present invention-
Since the phosphor layer includes the phosphor of the present invention represented by the following general formula that is manufactured at low cost and fluoresces with high emission intensity, the fluorescent lamp of the present invention is higher than a normal fluorescent lamp. It can be manufactured at low cost while having emission intensity.

General _{formula: M1 x (Sn l-y} Ti y) 2 M2 z M3 c O r
(In the formula, M1 is either Ca or Na. M2 is either Al or Si. M3 is a transition element of any one of Zr, Hf, Nb, and Ta. X is 1.5 ≦. x ≦ 2.5, y is 0.01 <y <0.2, z is 1.5 ≦ z ≦ 2.5, r is 8 ≦ x ≦ 10, and c is a number that satisfies 0 ≦ c ≦ 2. .)

As the phosphor of the present invention used in the fluorescent lamp of the present invention, preferred values and reasons for M1, M2, M3, and x, y, z, r and c in the general formula are described above. This is all the same as described in the description of [phosphor].

-Other ingredients-
As the other components contained in the phosphor layer, for example, phosphors of components other than the phosphor of the present invention that emit visible light by ultraviolet rays such as 253.7 nm emitted from mercury atoms are suitable. Can be mentioned. As such a phosphor, a phosphor with little deterioration against heat and less mercury adsorption is preferable. Further, when the fluorescent lamp is started, the mercury vapor pressure may continue to be high. Even in such a case, a phosphor that can suppress deterioration of the light-transmitting tube due to adsorbed mercury is preferable.

Examples of the phosphor include Y ₂ O ₃ : Eu, YVO ₄ : Eu, LaPO ₄ : Ce, Tb, (Ba, Eu) MgAl ₁₀ O ₁₇ , (Ba, Sr, Eu) (Mg, depending on the purpose). Mn) Al ₁₀ O ₁₇ , Sr ₁₀ (PO ₄ ) _{6 Cl 2} : Eu, (Sr, Ca, Ba, Mg) ₁₀ (PO ₄ ) _{6 Cl 2} : Eu, or the like is used. These may be used alone or in combination of two or more.

  In particular, known blue phosphors (such as BAM: Eu), green phosphors (such as LAP: Ce, Tb), and red phosphors (such as YOU: Eu) are preferably used for the purpose of white color correction and the like. .

<Other configurations>
Other configurations provided inside the light-transmitting tube include, for example, a low-refractive index protective layer including a material having a refractive index lower than that of the material of the light-transmitting tube. Providing such a low refractive index protective layer is preferable because the luminous flux of the fluorescent lamp is improved. In this case, the refractive index of the phosphor layer is preferably lower than that of the low refractive index protective layer. If desired, a high refractive index protective layer may be provided between the low refractive index protective layer and the phosphor layer.

Examples of the material for the low refractive index protective layer include calcium fluoride (CaF ₂ ), cerium fluoride / calcium fluoride (CeF ₃ + CaF ₂ ), magnesium fluoride (MgF ₂ ), and strontium fluoride (SrF ₂ ). , Barium fluoride (BaF ₂ ), Gryolite (Na ₂ AlF ₆ ), silica (SiO ₂ ), and the like. These may be used individually by 1 type and 2 or more types may be used together.

The thickness of the low refractive index protective layer is not particularly limited, but is preferably 0.05 μm to 3 μm, and more preferably 0.1 μm to 2 μm.
If the thickness of the low refractive index protective layer is greater than 3 μm, light may be absorbed by the low refractive index protective layer and the luminous flux may be reduced. On the other hand, if the thickness is less than 0.05 μm, light from the outside of the light transmission tube may be reduced. This is because it may be difficult to totally reflect.

  As described above, when the low refractive index protective layer is provided in the fluorescent lamp of the present invention, the light totally reflected at the interface between the light transmitting tube and the air is again formed at the interface between the light transmitting tube and the low refractive index protective layer. By totally reflecting, light can be emitted out of the light-transmitting tube, so that the luminous flux is improved.

<Encapsulated components in light-transmitting tube>
In the fluorescent lamp of the present invention, mercury and a discharge medium are sealed inside the light-transmitting tube, and other components are sealed as necessary.

  The mercury is excited by glow discharge generated by secondary electrons generated by the ionized noble gas, and generates ultraviolet rays including 253.7 nm. The vapor pressure of mercury sealed inside the light-transmitting tube is preferably, for example, 1 to 10 Pa when the fluorescent lamp is turned on.

  Examples of the discharge medium include a rare gas. When a starting voltage is applied to the electrode, the discharge medium is ionized by a slight amount of electrons in the light-transmitting tube, and collides with the electrode or the electron-emitting material described above. Secondary electrons are emitted. Examples of the rare gas include argon and neon. The amount of rare gas sealed in the light-transmitting tube is preferably, for example, 30 to 100 torr.

(Fluorescent lamp manufacturing method)
The method for producing the fluorescent lamp of the present invention is not particularly limited as long as it is an ordinary known method, and examples thereof include the following methods.

  First, a light-transmitting tube is prepared, and the inner surface of the light-transmitting tube is cleaned by firing at a predetermined temperature or the like to decompose residual organic matter.

  Next, in order to form a fluorescent layer, a phosphor-containing liquid containing the phosphor of the present invention is prepared. Here, examples of the solvent include ethyl alcohol, water, lower alcohols such as methyl alcohol and isopropyl alcohol, methyl formate, ethyl formate, propyl formate, isopropyl formate, butyl formate, isobutyl formate, sec-butyl formate, and the like. Formic acid esters, methyl acetate, ethyl acetate, propyl acetate, isopropyl acetate, butyl acetate, isobutyl acetate, sec-butyl acetate and other acetate esters, acetone, methyl ethyl ketone, methyl isobutyl ketone and other ketones, toluene, paraxylene Aromatic hydrocarbons such as orthoxylene can be used as appropriate. These may be used alone or in combination of two or more.

The phosphor-containing liquid may contain a binder component.
Examples of the binder component include phenol resin, epoxy resin, acrylic resin, cellulose resin (methyl cellulose, ethyl cellulose, nitrocellulose, etc.), PVP (polyvinyl pyrrolidone), polyvinyl acetal, PVA (polyvinyl alcohol), butyral resin, silicone resin, Etc. These may be used alone or in combination of two or more.

  If the binder component remains in the fluorescent lamp product, it may become an impurity, which may cause problems in the life (durability), luminance (brightness), antireflection effect, etc. of the fluorescent lamp product. For this reason, it is preferable to volatilize by firing described below so as not to remain substantially.

  Next, the prepared phosphor-containing liquid is applied to the inner surface of the translucent tube and baked to form a phosphor layer. The application method is not particularly limited, and any of a spraying method, a dip method, a suction method, a method of flowing a liquid into a light transmitting tube, and the like may be used. Further, the coating method may be an electrostatic coating method, a sol-gel method using a solution obtained by dissolving a metal alkoxide in an organic solvent, or the like.

  Then, an electrode connected with a lead wire is provided inside both ends of the translucent tube and sealed with a cap or the like, and then a discharge medium (rare gas) and mercury are sealed, and the end of the translucent tube is sealed. Stop.

  In the above method, for example, before applying the phosphor-containing liquid, a step of forming a low refractive index protective layer by applying a dispersion of the low refractive index protective layer on the inner surface of the light-transmitting tube and drying it is provided. May be. Moreover, before providing an electrode in a translucent tube, you may prepare the coating liquid containing an ionic crystal substance, and may apply this to the translucent tube inner surface and electrode surface near an electrode.

(Light emission operation of fluorescent lamp)
In the fluorescent lamp of the present invention described above, first, a voltage is applied to a pair of electrodes provided inside the light-transmitting tube. Then, discharge occurs between both electrodes through the discharge medium enclosed in the light-transmitting tube. Accompanying the discharge, mercury sealed in the discharge medium emits ultraviolet rays (main wavelength 254 nm) by excitation radiation. The generated ultraviolet rays are applied to the surrounding phosphor layers, thereby exciting the phosphor particles contained in the phosphor layers and generating visible light (wavelength of about 400 nm or more). Then, the visible light is transmitted to the outside through the light-transmitting tube, so that the fluorescent lamp of the present invention emits light.

  The fluorescent lamp of the present invention described above may be a cold cathode fluorescent lamp or a hot cathode fluorescent lamp, and is appropriately designed according to the application and purpose. Here, the cold cathode fluorescent lamp refers to a type of fluorescent lamp that is heated by a filament to emit thermoelectrons. The hot cathode fluorescent lamp refers to a type of fluorescent lamp that emits thermal electrons by heating with a filament when discharging.

  Since the fluorescent lamp of the present invention described above is manufactured at low cost and uses the phosphor of the present invention having high emission intensity, it can be manufactured at low cost while having high emission intensity.

  Examples of the present invention will be described below, but the present invention is not limited to the following examples.

Example 1
<Fabrication of phosphor>
The phosphor of Ca ₂ (Sn, Ti) ₂ Al ₂ O ₉ of the present invention was produced as follows.
First, CaCO ₃ , SnO ₂ , SiO ₂ , and TiO ₂ were used as raw materials. Of these raw materials, SnO ₂ and SiO ₂ are calcined at 1000 ° C. for about 6 hours, and CaCO ₃ and TiO ₂ are calcined at 200 ° C. for about 3 hours, and then weighed so that the elements have a predetermined molar ratio. Then, after dry mixing, it was pressure-molded into pellets having a diameter of 1 cm at about 50 MPa. Thereafter, using an electric furnace, it was fired at 1300 to 1400 ° C. for 12 hours and pulverized to obtain a powder. The atmosphere during firing was air or an oxygen atmosphere. By measuring the powder of the obtained fired body by X-ray diffraction, as shown in FIG. 3, the fluorescence represented by the composition formula: Ca ₂ (Sn _0.95 , Ti _0.05 ) ₂ Al ₂ O ₉ It was confirmed that a body was obtained. This crystal structure has an orthorhombic crystal system.

-Measurement of spectrum and emission peak intensity-
An emission spectrum of the obtained phosphor (composition formula: Ca ₂ (Sn _0.95 , Ti _0.05 ) ₂ Al ₂ O ₉ ) is shown in FIG. 1 (excitation light source wavelength: 254 nm). The emission peak intensity at this time is shown in FIG.

<Production of fluorescent lamp>
A cold cathode fluorescent lamp was produced as follows.
-Preparation of phosphor-containing liquid-
70 wt% of the phosphor obtained in Example 1 (composition formula: Ca ₂ (Sn _0.95 , Ti _0.05 ) ₂ Al ₂ O ₉ ), 18 wt% of Y ₂ O 3: Eu, and 12 wt% of LaPO 4: Tb A phosphor-containing liquid (solvent: butyl acetate) was prepared.

-Formation of phosphor layer-
Next, after the inner surface was washed with pure water, a translucent tube made of borosilicate glass having a diameter of 2.4 mm and a thickness of 0.2 mm, which was fired at 500 to 600 ° C., was prepared. A phosphor layer having a thickness of 20 nm was formed by applying the phosphor-containing liquid prepared above on the inner surface of this light-transmitting tube and baking it at 600 ° C.

-Production of fluorescent lamp-
Then, the electrode was arrange | positioned and it heated and sealed with the burner. Thereafter, argon gas, neon gas, and mercury were sealed, and the end portion of the light-transmitting tube was sealed to produce a cold cathode fluorescent lamp.

  As can be seen from FIGS. 1 and 2, it can be seen that the phosphor obtained in Example 1 emits light with sufficiently high intensity when excited with mercury rays (wavelength: 254 nm) in a fluorescent lamp. A blue-greenish white fluorescence was obtained. Furthermore, since the phosphor of the present invention was used as the phosphor used in the fluorescent lamp, the fluorescent lamp was manufactured at low cost.

(Example 2)
A phosphor was prepared under the same conditions as in Example 1, and a phosphor having a composition formula of Ca ₂ (Sn _0.975 , Ti _0.025 ) ₂ Al ₂ O ₉ was obtained. The emission peak intensity was measured. The result of the emission peak intensity is shown in FIG.

Example 3
A phosphor was produced under the same conditions as in Example 1, and a phosphor having a composition formula of Ca ₂ (Sn _0.9 , Ti _0.1 ) ₂ Al ₂ O ₉ was obtained. The emission peak intensity was measured. The result of the emission peak intensity is shown in FIG.

Example 4
A phosphor was prepared under the same conditions as in Example 1, and a phosphor having a composition formula of Ca ₂ (Sn _0.8 , Ti _0.2 ) ₂ Al ₂ O ₉ was obtained. The emission peak intensity was measured. The result of the emission peak intensity is shown in FIG.

  As described above, as can be seen from FIG. 2, it was found that the emission peak intensity in the phosphors obtained in Examples 1 to 4 depends on the titanium content (composition) in each phosphor composition.

Claims (7)

General _{formula: M1 x (Sn l-y} Ti y) 2 M2 z M3 c O r
(In the formula, M1 is either Ca or Na. M2 is either Al or Si. M3 is a transition element of any one of Zr, Hf, Nb, and Ta. X is 1.5 ≦. x ≦ 2.5, y is 0.01 <y <0.2, z is 1.5 ≦ z ≦ 2.5, r is 8 ≦ x ≦ 10, and c is a number that satisfies 0 ≦ c ≦ 2. )), A phosphor.   The phosphor according to claim 1, wherein, in the general formula, M1 is Ca, M2 is Al, and c is 0.   3. The phosphor according to claim 1, wherein x and z are 2 and r is 9 in the general formula.   4. The phosphor according to claim 1, wherein the crystal structure is an orthorhombic crystal system and the space group is Pbcn.   A fluorescent lamp having a translucent tube, an electrode for generating a discharge and a phosphor layer inside the translucent tube, and further mercury and a discharge medium enclosed in the translucent tube, wherein the phosphor layer is A fluorescent lamp comprising the phosphor according to any one of claims 1 to 4.   The fluorescent lamp according to claim 5, which is a hot cathode fluorescent lamp.   The fluorescent lamp according to claim 5, which is a cold cathode fluorescent lamp.

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