DE2944815A1 - LUMINAIRES AND METHOD FOR THEIR PRODUCTION - Google Patents

Description

PATEN TANWÄLTE

SHIP v. FÜNER STREHL SCHÜBEL-HOPF · 'EBBINaHAUS FINCK

MARIAHILFPLATZ 2 A 3, MÖNCHEN 9O ^ J J 4 HQ j Q POSTAL ADDRESS: POSTFACH ΘΒ O1 6O, D-8OOO MÖNCHEN »5

HITACHI, LTD. November 6, 1979

DEA-25043

Phosphors and processes for their manufacture

;; / π π U 7

-I; 504 3

DESCRIPTION

The invention relates to phosphors, particularly rare earth oxide sulfide phosphors and a method for their manufacture. In particular, it relates to phosphors containing terbium and / or praseodymium are activated and a process for their preparation.

Rare earth oxide sulfide phosphors are from the US Pat. No. 3,502,590 and show after excitation with ultraviolet rays, X-rays and Cathode ray luminescence. In particular, the terbium-activated phosphors are used for X-ray screens with enhanced luminosity and used for color television projection equipment. These phosphors however, they are unsatisfactory in their luminosity and hue.

With the recent development of color television picture tubes, electron guns and the like, the brightness is increasing of the screen by increasing the current density for the excitation of the phosphor. In the case of one Color television projection device is the phosphor to increase brightness with a current density excited, which corresponds to at least five times the current density of a conventional television picture tube. if a common green emitting phosphor, that is, a ZnS phosphor, is used for such cathode ray tubes can, even if the density of the irradiating electron beam is increased, a sufficient brightness cannot be achieved because the brightness has reached a saturation value, whereby

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the further disadvantage is that the hue of the screen changes as the brightness changes changes.

Phosphors activated with rare earth element ions are used for color television projection devices, since the appearance of the phenomenon of saturation of brightness under the action of the irradiating Electron beam is significantly reduced. However, the praseodymium-activated rare earth element oxide sulfide show phosphors insufficient brightness, even if you have an excellent green hue achieved, while the terbium-activated rare earth element oxide sulfide phosphors have a yellow hue show, which differs significantly from the hue of conventional ZnSrCu, Al phosphors.

As prior art, reference is made in particular to US Pat. No. 3,520,590.

The object of the present invention is to find extremely effective phosphors and methods to create them.

This object is now achieved by the phosphor according to the main claim.

The invention therefore relates to the phosphors according to the main claim; particularly preferred embodiments these phosphors are the subject of subclaims 2 to 6.

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The invention further relates to a method for producing these phosphors according to the claims 7 to 9.

The invention relates in particular to the luminous substances of the general formula I below

^ _xx22 (I)

^{in the}

Ln for at least one element from the group consisting of yttrium, gadolinium, lanthanum and lutetium

Group,
A for at least one element from the praseodymium

and group comprising terbium, X for at least one member of fluorine and

Group comprising chlorine and χ for a number with a value in the range of 0.00003 <χ <0.2

and the amount of X is 2 to 1000 ppm by weight.

The invention will be explained in more detail below with reference to the accompanying drawings.

In the drawings show:

1 shows the luminescence spectrum of a phosphor according to the invention and

Fig. 2, 3 and 4 curves, on the basis of which the invention is explained in more detail.

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In the phosphor of the present invention, the brightness becomes or the luminosity of the material is improved by keeping the value of χ within the above holds specified range, it is preferred if χ is in the range of 0.00003 χ 0.01. if X is fluorine, it is preferred that this element be present in an amount of from 2 to 300 parts per million by weight based, is present, while X is preferably chlorine in an amount of 10 to 300 ppm and especially in an amount of 10 to 150 ppm, all based on weight is.

The brightness or the luminosity of the phosphors according to the invention is compared with the brightness or the luminosity of the halogen-free fluorescent material by a few percent up to 30 percent or more improved, the hue of the phosphors according to the invention being the same as that of the halogen-free Phosphors.

The phosphors according to the invention are obtained with the aid of the method according to the invention, which thereby is marked that one

1.) an oxide mixture that meets the requirements of the general formula II below

< ^Ln 1-x ^A x> 2 ° 3 ^(II)

in the

Ln, A and X have the meanings given above,

corresponds to, or a material which, when heated, turns into an oxide of the above general formula II is converted,

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2.) a material which forms an alkali metal sulfide when heated, and

3.) a compound which contains at least one element from the group comprising fluorine and chlorine, mixed and the mixture heated.

_{Mixtures of Ln 2} O ₃ and an oxide of terbium or praseodymium in the desired ratio can be cited as an oxide mixture which meets the requirements of the above general formula II, or as a material which gives an oxide of the general formula II on heating and Ln-Oj compounds in which a part or all of Ln is replaced by a phosphate, oxalate or carbonate.

As a material that, when heated, forms an alkali metal sulfide forms, one can use, for example, mixtures such as a mixture of an alkali metal carbonate and Sulfur, a mixture of an alkali metal sulfite and sulfur, a mixture of an alkali metal thiosulfate and sulfur and a mixture of an alkali metal thiocyanate and sulfur, and compounds, such as an alkali metal thiocyanate. Of these materials, it is preferable to use a mixture of one Alkali metal carbonate and sulfur.

As a compound containing fluorine, one can, for example, name RHF-, RSO ₃ F, R ₂ GeFg, R ₂ TiF, R ₂ PFg, LiBF ₄ , NaBF ₄ , KBF ₄ and R ¹ F ₂ .

As a compound containing chlorine, one can, for example, name RCl, RbCl, CsCl, R ¹ Cl ₂ , SnCl ₂ , PdCl ₂ , R ¹¹ Cl ₃ , RClO ₃ , NaClO ₄ , KClO ₄ , CsClO ₄ , RbClO ₄ , NH ₄ ClO ₄ , Zn (ClO ₃ J ₂ , Sr (ClO ₃ ) ₂ , Ba (ClO ₃ ) ₂ , R ^Ml (ClO ₄ ) ₂ and In (ClO ₄ J ₃ .

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In the above general formulas, R stands for lithium, sodium, potassium or ammonium, R ¹ for magnesium, calcium, strontium, barium, zinc or cadmium, R "for aluminum, gallium, yttrium, indium, lanthanum, gadolinium, lutetium, praseodymium, Terbium, cerium or scandium and R ^lM for calcium, strontium, magnesium or barium.

_{Na 4} PO ₇ and NaH ₃ PO ₄ , for example, can be used as flow agents.

The applied for the production of the phosphors of the present invention temperature is preferably in the range of 9OO to 1400 ⁰ C and preferably in the range from 1000 to 1300 ^0C

Fig. 1 illustrates the luminescence spectrum of the phosphor according to the invention of the following formula (Gd _{Q 999P ^ 0 0Q1} ) 3O ₃ S: (F), which with ultraviolet

th rays has been excited. The luminescence spectrum of this phosphor is the same as that of the fluorine-free phosphor, but the height of the emission peak is larger.

As already mentioned, in the case of the phosphors according to the invention, the luminescence brightness or luminosity is improved while the saturation of brightness or luminosity is decreased. As a result, can one with the phosphors according to the invention color picture tubes with much improved image quality and you can with color television projection equipment improve the brightness significantly.

For example, a monochromatic television

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Projection device in a conventional manner by forming the screen by sedimentation using a phosphor represented by the following formula ( ^γ _Λ Oc ¹ Tb _n ., J ₁ OS: (F) (where the fluorine content of the phosphor is 500 ppm) monochromatic television projection device using a phosphor of the formula ZnStAu, Cu, Al.

With an excitation current of 500 μΑ, the brightness of the two projected television images compared, it was found that the brightness of the using a projected television image obtained according to the invention was about 25% larger than that of the projected television image obtained using the conventional phosphor.

As a phosphor for the manufacture of such color television projection equipment Phosphors of the above general formula I, in which A stands for terbium, are preferred because their luminescence brightness is greater.

As already mentioned, the hue of the luminescence of terbium-activated rare earth oxide sulfides is yellow and the hue of the luminescence of the terbiura-activated phosphors according to the invention is also yellow, albeit yellow the brightness or the luminosity of the material is improved compared to the conventional phosphor is. On the other hand, the prasaodymium-activated phosphors according to the invention exhibit luminescence with an excellent green color, the brightness or luminosity being compared to the corresponding halogen-free phosphor is improved, although the brightness or the luminosity of this

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Phosphor is inferior to that of the conventional phosphor of the formula ZnS: Cu, Au, Al. if if both phosphors are mixed, the luminescence of the mixture is compared to the hue of the luminescence of the praseodymium-activated phosphor yellowish, improving the brightness or the luminosity is. However, this yellowish green is also viewed as green via the color contrast. This can be readily explain that, despite the fact that the luminescence of the conventional phosphor the formula ZnS: Cu, Au, Al is more yellowish than the green signal of the NTSC system, this phosphor normally used as a green-emitting phosphor.

If a phosphor mix is used, should the mixed phosphors each other in terms of brightness properties in terms of the Excitation current in such a way that it is similar to itself if the excitation current changes, the hue is not changed. For example, if you have the inner surface of the front plate of a cathode ray tube coated in the usual way with a mixture, which consists of two parts by weight of a luminous

The substance of formula (Gd ₉₈ Tb _{Q Q O2)} 2 ° 2 ^{S: is F and a Ge} ~ part by weight of a phosphor of the formula ^ ^ Ο.ΘΘΤ Ο.ΟΟΒ ^^ ⁸ ** "'is the brightness of the green image of the cathode ray tube when excited with a current of 5OO μΑ 115, while the brightness of the conventional phosphor of the formula ZnS: Au, Cu, Al is 100. The color coordinates of the above mixture (point 3 of FIG. 2) are very similar to those of the conventional phosphor ( Point 4 of Fig. 2). In Fig. 2

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the points 1, 2 and 5 stand for the color coordinates of the above-mentioned praseodymium-activated phosphor, of the above-mentioned terbium-activated phosphor or the green signal of the NTSC system.

Another example of a phosphor mixture is given below explained

A phosphor of the formula ( ^Gd n 997 ^Pr o OO3 ^ 2 ° 2 ^{S: F and a} phosphor of the

Formula (Gd_ _no Tb._ __) _o 0_S: F in which below u.yö υ.υ / ί ζ.

the mixing ratio given in Table I and prepare using this mixture in the above described way a cathode ray tube. The brightness (a relative number based on the assumption it was calculated that the brightness of the conventional phosphor of the formula ZnS: Au, Cu, Al is 100) and the color coordinates of this mixture are also given in Table I below. It is without it can also be seen that if one uses the former phosphor (Pr in the table, X = 0.215, Y = 0.627, Brightness = 59) with the latter phosphor (Tb in the table, X = 0.349, Y = 0.555, brightness = 158) mixed and the mixture used, one a cathode ray tube with a green emitting Screen that is characterized by great brightness or high luminosity.

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0.1 Tabel X I. Hell I 0.2 Y Mix
relationship 0.3 0.336 148 Tb 0.4 0.322 0.563 138 0.9 0.5 0.309 0.569 129 0.8 0.6 0.295 0.577 119 0.7 0.7 0.283 0.584 1O9 0.6 0.8 0.269 0.592 98 0.5 0.9 0.256 0.598 88 0.4 0.242 0.606 79 0.3 0.229 0.613 69 0.2 0.620 0.1

In the phosphors of the present invention, the brightness is improved when excited by X-rays. For example, the brightness or the luminosity of a phosphor according to the _{invention of the formula (Gd Q 93Tb 0 2} ) ₂ O ₂ S: (F) (added fluorine concentration = 9,400 ppm, based on the weight) when excited with 120 kV X-rays of a tungsten target 114, while under the same conditions the brightness of the
conventional fluorine-free phosphor is 100.
Under the same excitation conditions, the
Brightness or the luminosity of the phosphor according to the invention of the formula (Gd_ ₉ qq ^Pr _o OO1 * 2 ° 2 ^S: * ^F * ( ^to 9 ^e "set fluorine concentration = 9,400 ppm, based on weight) 127, while the brightness or luminosity of the corresponding fluorine-free phosphor is only 100. Accordingly, the phosphors according to the invention can be used in an effective manner for the production of detectors for radioactive radiation and
use for X-ray intensifying screens.

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The following examples serve to further illustrate the invention.

example 1

^Gd 2 ° 3 33.318 g

GdPQ ₄ -0.904H ₂ O 4.294 g

Pr ₆ O _n 0.0341 g

S 9.561 g

K ₃ PO ₄ OH ₂ O 3.233 g

Na ₄ P ₂ O ₇ 0.984

Na ₂ CO ₃ 9.572 g

KCl 0.671 g

An acrylic resin jar with a capacity of about 200 ml is charged with the above starting materials and mixed by rolling the jar. The mixture is then transferred to an aluminum oxide crucible with a capacity of 50 ml and closed with an aluminum oxide lid. Then you burn the mixture in air for 3 hours at 118o ⁰ C. It removes the yellowish product of the alumina crucible and dipped it in water immediately. The liquid is stirred with a stirrer, the solution _{turning yellow due to the leaching of Na 2 S.} The material is washed with hater until the washing liquid becomes colorless, whereupon the washed solid is passed through a sieve with a mesh size of 0.044 mm (325 mesh). The supernatant liquid is decanted off and discarded, and 500 ml of a 0.5N aqueous solution are added to the residue

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Hydrochloric acid solution and stir the mixture for one hour. After the treatment with hydrochloric acid, the phosphor is washed with pure water until the conductivity of the washing liquid is less than 10 μ Λ -cm. The phosphor is allowed to settle, the supernatant liquid is discarded and the phosphor obtained is dried at 140.degree. The phosphor obtained in this way has the composition corresponding to the following formula; ( ^Gd _o 9qo ^Pr o OO1 ^ 2 ° 2 ^{S: C1 and contains} chlorine in a concentration of 67 ppm, based on the weight. The brightness or luminosity of this phosphor with exciting light with a wavelength of 254 nm is 130, if one assumes that the brightness of a comparative phosphor prepared in the same way, but without the addition of KCl, is 100.

Examples 2 until 5 35 , 160 G 20th
Gd ₂ O ₃ 1 , 122 G Tb ₄ O ₇ 6th , 830 G S. 6th , 836 G ₂₅ ^Na 2 ^CO 3 2 , 308 G K ₃ PO ₄ OH ₂ 0

The starting materials given above are mixed with NH ₄ PF ₆ in an amount corresponding to the fluorine content given in Table II below (where Ln ^{1 in} Table II below stands for the sum of the elements, i.e. the sum of praseodymium and terbium ) and treated the mixture obtained according to the method described in Example 1

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DEA-25043

rensweise, whereby one obtains a phosphor of the following formula: (Gd _{Q 97} Tb _{Q I3} ) ₂ ° 2 ^{S: (F} **

As can be seen from Table II below, a phosphor with improved relative brightness is obtained. The luminescence spectrum of the phosphor is the same as that of the conventional fluorine-free phosphor.

Tabel II Fluorine content
(ppm, on
the weight
based) relative
brightness example
No. added fluorine
concentration
(ppm, on the Ge
weight related)
(F / Ln ¹ ^) 0 100 Comparison
example O 2 108 2 31 4th 117 3 314 10 120 4th 1571 42 123 5 9427 5490 55 Comparison
example 62844

Examples 6 to 9

One prepares phosphors of the formula

^{according to the} procedure

of Example 1, with the difference that NH ₄ PF _{6 is} used instead of KCl. The concentration of NH ₄ PF _{6 added} , the fluorine content and the relative brightness of the phosphor obtained are listed in Table III below. at

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each phosphor the relative brightness is improved, while the luminescence spectrum is the same is like that of the fluorine-free phosphor.

Tabel III relative
brightness Example no. added fluorine
concentration
(ppm, on the Ge
weight related)
(F / Ln ' ₂ O ₃ ) Fluorine content
(ppm, on
the weight
based) 100
129
128
134
123 Comparison
example
6th
7th
8th
9 0
1259
3147
9442
31474 0
9
35
91
119

Examples 10 to 15

Phosphors of the following formula (Gd _{n QQgPr 0 no} ) ₂ 0 ₂ S: (Cl) are prepared by the procedure of Example 6, with the difference that instead of the fluorine compound, KCl is used as the starting material in the amount given in Table IV below . In the case of each phosphor, the relative brightness is improved compared to the comparison phosphor prepared without the addition of KCl, while the luminescence spectrum is identical to that of the comparison phosphor.

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Tabel IV relative
brightness Example no. added chlorine
concentration
(ppm, on the Ge
weight related)
(Cl / III ' ₂ O ₃ ) Chlorine content
(ppm, on the
Weight related
ben) 100 Comparison
example 0 0 106 10 50 10 107 11 294 14th 123 12th 2940 36 13O 13th 8821 67 119 14th 17642 90 101 15th 196024 158 Example 16

Phosphors of the formula (Gd ₁ Tb) ₂ O ₂ S: (F) are prepared according to the procedure of Example 1, with the difference that the Gd / Pr ratio is changed _{instead of Pr 6} O ₁₁ Tb.0- and instead of KCl NHj ₁ PF, uses (where

4 D

the fluorine content is 42 ppm). It turns out that the improvement in brightness by the added Halogen depends on the activator ion concentration in the phosphor. This relation is made by Fig. 3 clarifies. Curve 6 shows the brightness of the phosphor with a fluorine content of 42 ppm, while curve 7 shows the brightness of the fluorine-free comparison phosphor. In that area, in which the activator ion concentration is high and the reduction in concentration by the mutual action of the ions predominates, is the

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The effect of the fluorine ions is low. A similar relationship is also observed in the praseodymium-activated one Fluorescent. When the activator ion concentration is low, the effect of the fluorine ions is great. Even at a terbium concentration of 3 10, the effect of the fluorine ions can be observed.

The relationship observed for a phosphor of the formula (Gd _1- Pr) _0_S: (F) prepared according to the procedure of Example 9 is shown in FIG. 4, in which curve 8 shows the brightness of this phosphor and the curve 9 show the brightness of the fluorine-free comparison phosphor.

Examples 17 to 24

Gd ₂ O ₃ 36.143 G Tb ₄ O ₇ 0.1122 G S. 6.830 G Na ₂ CO ₃ 6.836 G K ₃ PO ₄ OH ₂ O 2.308 G

The starting materials given above are mixed with one of the fluorine compounds given in Table V below and the mixture is treated in the manner described in Example 2 to give phosphors of the formula (Gd _g97 Tb ₃ ) ₂ O ₂ S: (F). The added fluorine concentration is 9442 ppm by weight and calculated as F / Ln'-O. The fluorine content of the phosphor averages 42 ppm by weight, although the fluorine content depends to some extent on that of the starting material

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used fluorine compound varies. With every phosphor there is an improvement in the relative Hel to watch.

Table V

example
No. Fluorine compound 25th added amount
(G) relative
brightness Comparison
example no One prepares phosphors 0 100 17th (NH ₄ I _{2 GeF 6} ^(Gd O.999 ^P] 0.668 156 18th Li ₂ GeF ₆ ^r O.OO1 ^} 2 ° 2 ^{S: (Pl)} 0.601 155 19th Na ₂ GeF ₆ 0.698 152 20th K ₂ GeF ₆ 0.794 152 21st LiPF ₆ 0.478 145 22nd NaPF ₆ 0.504 158 23 KPF ₆ 0.552 155 24 0.489 164 Example : the formula according to the procedure

of Example 10, with the difference that instead of KCl BaCl ₂ · 2Η ₂ Ο, ZnCl ₃ , AlCl ₃ -6H ₂ O, NH ₄ Cl, KClO ₃ or NaCl in a concentration of 821 ppm, based on the weight and calculated as Cl / Ln ' ₂ O ₃ , used. In these phosphors, the chlorine content is 67 ppm on average, although the chlorine content varies to some extent depending on the kind of the chlorine compound used. The relative brightness values of these phosphors are 127, 130, 127, 128, 131 and 131, respectively

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the brightness of the chlorine-free comparison phosphor 100 is.

Example 26 33,318 G Gd ₂ O ₃ 4.032 G GdPO ₄ 0.0341 G ^Pr 6 ° 11 9,561 G S. 3.233 G K ₃ PO ₄ -SH ₂ O 0.984 G Na ₄ P ₂ O ₇ 9,572 G Na ₂ CO ₃ 0.185 G NaHF ₂

The mixture of the above starting materials are treated according to the procedure of Example 1 to form a phosphor of the formula (Gd ₀ 999 ^Pr o 001'2 ° 2 ^{S * F} ** ^This phosphor has a fluorine content of 21 ppm, the relative brightness of this. Phosphor is 118 compared to the brightness of the fluorine-free comparative phosphor, which is 100 by definition.

Example 27

A phosphor is prepared according to the procedure of Example 26, with the difference that 0.3512 g of NH ₄ SO ₃ F is used _{instead of NaHF 2.} The fluorine content of this phosphor is 10 ppm and

its relative brightness is 105. 30

Example 28

A phosphor is prepared according to the procedure of Example 26, with the difference that

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instead of NaHF ₂ 0.3294 g NaBF _{4 was} used. The fluorine content of this phosphor is 33 ppm and it has a relative brightness of 124.

Example 29

Y ₂ O ₃

^{Y (PO 4)} 1.O99- ¹ - 2 ° ^O4H

Tb ₄ O ₇

K ₃ PO ₄ -3H ₂ O Na ₄ P ₂ O ₇ Na ₃ CO ₃ NH ₄ PF ₆

19.738 g

3.223 g

1.8693 g

9.561 g

3.233 g

0.984 g

9.572 g 0.4889 g

The mixture of the starting materials indicated above is treated in the procedure described in Example 1 to form a phosphor of the formula (Y _{Q 95} Tb ₀ Q ₅ J ₂ O ₃ St (F). The fluorine content of the phosphor is 60 ppm and it has a Luminescence spectrum which corresponds to that of the fluorine-free comparative phosphor. The relative brightness is 160, while the brightness of the fluorine-free comparative phosphor is, by definition, 100.

Example 30

Y ₂ O ₃

^{Y (PO} 4> 1.O99 * ^{1 'O4H} 2 °

^Pr 6 ° 11

K ₃ PO ₄ OH ₂ O Na ₄ P ₂ O ₇ Na ₂ CO ₃ KCl

20.767 g

3.391 g

0.0341 g

9.561 g

3.233 g

0.984 g

9.572 g

0.6710 g

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A mixture of the abovementioned starting materials is treated according to the procedure of Example 1 to give a phosphor of the formula (Y _{0 999} Pr _{0 OO1} ) ₂ O ₂ S: (Cl). The chlorine content of the phosphor is 75 ppm and it has a relative brightness of 132 on the basis that the brightness of the comparative chlorine-free phosphor is 100.

Example 31

La ₂ O ₃ 32.486 g

Tb ₄ O ₇ 0.1122 g

S 6.830 g

Na ₃ CO ₃ 6.836 g

K ₃ PO ₄ OH ₂ O 2.308 g

(NH ₄ ) ₂ GeF ₆ 0.111 g

A mixture of the starting materials given above is treated in that given in Example 1

Way to form a phosphor of formula 20

(La _{Q g97} Tb _{Q OO} 3) 2 ° 2 ^S: ' ^F '' ^{which has a} fluorine content of 11 ppm. The luminescence spectrum of this phosphor corresponds to that of the fluorine-free comparative phosphor. The relative brightness is 110 compared to the brightness of the fluorine-free comparison phosphor, which is defined as 100.

example 32 1 Lu 2 ° 3 Pr 6 ° 1 3 S. * ^3H 2 ° N / A ₂ co 6th ^K 3 PO ₄ NH ₄ PF

39.798 g

^Pr fi ° ii 0.0341 g

6.830 g

6.836 g

2.308 g

0.489 g

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A mixture of the abovementioned starting materials is treated according to the procedure of Example 1 to form a phosphor of the formula (Lu _0.9gg Pr ₀₀₀₁ J ₂ O ₂ S: (F) which has a fluorine content of 35 ppm. The luminescence spectrum of the phosphor is The relative brightness of this phosphor is 115, while the brightness of the comparative fluorine-free dye is 100. 10

Example 33 32.627 G Gd ₂ O ₃ 1.129 G Y ₂ O ₃ 1,869 G Tb ₄ O ₇ 6.830 G S. 6.836 G Na ₂ CO ₃ 2.308 G K ₃ PO ₄ OH ₂ O 0.489 G NH PF ₆

A mixture of the above starting materials is treated according to the procedure of Example 1 to form a phosphor of the formula (Gd _{0 9} Y _{Q 05} Tb _{0 O5} ) ₂ O ₂ S: (F) which has a fluorine content of oc 8 ^ PP ^m having. The relative brightness of the phosphor is 132, while the brightness of the fluorine-free comparison phosphor is 100 by definition.

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Claims (9)

DEA-25043 CLAIMS 1. Phosphors of the general formula I (D in the Ln for at least one element selected from yttrium, gadolinium, and lanthanum Lutetium comprising group, A for at least one element from the Praseodymium and terbium comprising group, X for at least one representative of the fluorine and group comprising chlorine and χ for a number with a value in the range from 0.00003 <χ <0.2 and the amount of X is 2 to 1000 ppm by weight. 2. phosphor according to claim 1, characterized characterized in that χ in the general formula has a value in the range of 0.00003 <χ <0.1.
25th 3. phosphor according to claim 1, characterized characterized in that X is fluorine and the amount of X is 2 to 300 ppm by weight related, amounts to. 4. Phosphor according to claim 1, characterized in that X is chlorine and the amount of X is 10 to 300 ppm by weight. 03C0 19/0947 ORIGINAL INSPECTED DZA-25043 29U815 5. phosphor according to claims 1 to 4, characterized in that Ln in the general formula stands for gadolinium. 6. phosphor according to one of claims 1 to 4, characterized in that Ln in the general formula stands for yttrium. 7. Process for the production of the phosphors according to Claims 1 to 6, characterized in that that he 1.) an oxide mixture that meets the requirements of general formula II ^(Ln 1-x ^A x> 2 ° 3 < ^XI > in the Ln, A and χ have the meanings given in claim 1, corresponds to, or a material which when heated to an oxide of the above general Formula II is converted; 2.) with a material that when heated a Alkali metal sulfide forms and 3.) a compound which contains at least one element from the group comprising fluorine and chlorine,
mixed and the mixture heated. 8. The method according to claim 7, characterized in that the mixture ai heated to a temperature of 900 to 14OO ° C. 0 / ■ '; 94 DEA-25043 9. The method according to claims 7 and 8, characterized in that that, as a material which gives an alkali metal sulfide on heating, at least one representative the group used, which is a mixture of an alkali metal carbonate and sulfur, a mixture of an alkali metal sulfite and sulfur, a mixture of an alkali metal thiosulfate and sulfur, a mixture of an alkali metal thiocyanate and sulfur, and a Alkali metal thiocyanate. Π /, -. <■■ /, 7