DE2250231A1 - LUMINOUS PHOSPHORUS - Google Patents

Description

PATENTANWÄLTE 8902 Goggingen near Augsburg, χ October 2, 1972

DIPL.ING. G. LIEBAU

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Thorn Electrical Industries Limited Thorn House, Upper Saint Martin's Lane London WC2H 9ED / England

Luminous phosphor

The luminous phosphor according to the invention contains yttrium aluminate activated by cerium which, although slightly excitable by ultraviolet radiation as well as cathode radiation and X-rays , is excited by blue light, for example the mercury line h 358 8, and then emits at a longer wavelength.

The luminous phosphor according to the invention has a pale yellow body color and therefore looks like a yellow pigment, absorb blue light. An essential characteristic of phosphorus, however, is that it is a part of the absorbed Emits energy again as light of greater wavelength. Another property of the phosphorus of interest here is also that it has its fluorescent properties Maintains at a temperature of a few hundred degrees Celsius and is therefore used in electric discharge lamps that get hot in use.

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09816/1172

INSPECTED

22B0231

Thus, a useful property of the present phosphor is that it is incorporated into mercury discharge lamps can be used to improve the emission of visible radiation by increasing the intensity of the blue mercury lines (e.g. the U358 Ä line) and converts some of the unnecessary blue light into usable light of greater wavelength.

The luminous phosphor according to the invention is advantageous used in fluorescent lamps where careful Monitoring of light emission is required, for example in lamps for photocopying or for special » Tasks of color rendering, and is also useful for influencing the light output of high-pressure mercury lamps. The phosphor can also be used for other discharge lamps Kinds are used in which the light emission in the blue is reduced and the light emission in an area is greater Wavelength should be amplified.

The phosphor of the present invention can be produced by heating yttrium oxide together with aluminum and cerium oxide or compounds of these which can be decomposed into oxides Metals. To form the phosphorus, ammonium chloride can advantageously be added to the mixture. the Cerium concentration is not critical, but is generally between 0.1 and 7.5% of the total weight of Yttrium and alumina and is preferably about 0.75%. The ammonium chloride content is not critical and can be up to 40% of the weight of the yttrium oxide used and alumina. Preferably about 7.5% is used.

The X-ray diffraction analysis of the phosphor shows that he usually occurs in yttro garnet structure, which is a

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Composition 1 Y ₂ ° 3 ^{: 5} ^ ^{3 A1} 2 ^ 3 ^{according to} P ^r i ^cht ii, ^however , it is preferable to prepare the phosphorus with an excess of alumina and the preferred molecular ratio of the starting material is 1 Y ₂ ° 3 ' ^{3 A1} 2 ° 3 *

The starting material for the production of the fluorescent phosphor should be within the framework of the fluorescent technology of usual purity.

For example, an approach for the production of a phosphor according to the invention is given below:

65 G ^Y 2 ° 3 7, 65 G Al ₂ O ₃ 1, 00 G NH ₄ Cl ο, 40 G (NH _1. )

[Ce CnO ₃ ) β]

These substances are ground together and heated for one hour at 125O ° C in a closed quartz crucible « After cooling. e η the product is ground and again for 16 hours at 1250 to 128O ° C all in one closed quartz crucible heated. After cooling it will the product ground into a fine powder, washed with demineralized water, dried and sieved.

The resulting powder has a pale yellow body color and when irradiated with blue light (e.g. with light of the line 4-358 Ά ¹ from a mercury vapor lamp) emits radiation of a longer wavelength with a maximum at around 5420 Pv and a half-width of around 100 ί? the end. A phosphor shows a slight fluorescence in the green when irradiated with 3650 8 and also a green emission when excited by cathode rays.

3 0 ti ;, 1 G / 1 1 7 2. \.

ORIGINAL

The drawings Fig. 1 and Fig. 2 show the adjustment of a Fluorescent lamp or a mercury vapor lamp to which the invention is applied.

Fig. 1 shows a conventional fluorescent lamp with a Mercury vapor filling; the lamp has a glass jacket 6 with end caps 7 and 8 through the leads 9 lead to cathodes (not shown). A layer 10 of fluorescent phosphor according to the invention is on the inside of the glass jacket 6 applied. Fig. 2 shows the high pressure mercury lamp with the usual arrangement a discharge tube (not shown) which is held by a metal grid 4. Around the discharge tube and the grid leads a spherical piston-shaped jacket 12, on the inside of which a layer S of the invention Phosphorus is applied.

Claims ι

309816/1 172

Claims (4)

Patent claims; Luminous phosphor, characterized in that it consists of yttrium aluminate activated by cerium. 2. Luminous phosphor according to claim 1, characterized in that the proportion of cerium is between 0.1 and 7.5 percent by weight the total amount of yttrium and aluminum, calculated «as yttrium oxide and aluminum oxide, is * 3. Luminous phosphor according to claim 1 or 2, characterized in that the ratio of yttrium to aluminum is between 1 ^Y 2 ° 3 ^{: 5} ^ ^{3 A1} 2 ° 3 ¹ ^ ^{1 Y} 2 ° 3 ^{: 3 A1} 2 ° 3 4. Application of a luminous phosphor according to the claims up to 3 in a mercury vapor lamp, 5, application of a luminous phosphor according to claims 1 to 3 in a fluorescent lamp. 3098 16/1172 Lee r side