HU202333B - Low-pressure mercury vapour discharge source of light in first of all electric discharge lamp with a luminescent layer having inactive ingredient and a luminescent composition for mercury vapour discharge source of light - Google Patents

Abstract

A low-pressure mercury discharge light source, particularly a fluorescent lamp of high wall loadability with luminescent coating, including an inactive component, comprises a vessel (1) coated on its inner surface with a luminescent coating (2) including an inactive component, the vessel (1) being pervious to radiation of predetermined wavelength, an excitable and ionizable filling consisting of a rare gas and mercury, the filling being arranged within said vessel (1) and means (3) for maintaining a gas discharge process within the vessel (1). The luminescent coating (2) consists of at least one luminescent component and an inactive component, the inactive component (such as alkali earth metal diphosphate) contains grains of average size smaller than that of grains forming the luminescent coating (2), the inactive component being positively charged and the amount of the inactive component lying in the range of about 0.1 mass% to about 2 mass% compared to the mass of the luminescent coating (2). <IMAGE>

Description

The present invention relates to a low-pressure discharge lamp having a luminescent material containing an inactive component, in particular a fluorescent lamp, preferably a high-load (compact) fluorescent lamp, and a composition comprising a luminescent material for use with a light source.

X-ray discharge lamps with luminescent material, also known as fluorescent powder, generally reduce the luminous flux emitted by fluorescent lamps over their lifetime. The degree of reduction also depends on the type of light source, including the type of fluorescent light used. To slow down or decrease the decrease. many methods have been developed to prevent it. The methods are different because the reasons for the decline are also different. Such as the preamble of GB 1 343 250.

One of the reasons is that the fluorescent light is not completely neutral. In fact, in the production of a fluorescent lamp used in the manufacture of a low-pressure discharge light source, in particular a fluorescent lamp, activator ions must be incorporated into the lattice of the basic crystal forming the fluorescent lamp. Mostly, ultraviolet radiation from mercury discharges light and illuminates it in the visible light range. However, incorporation of activator ions into the lattice is not easy and can only be achieved if anion is present in excess in the crystal. At this point, the duster will be stable. On the other hand, stable phosphor is negatively charged due to excess anion content compared to stoichiometric ratios. Negatively charged phosphor attracts positively charged mercury ions in the discharge chamber. Mercury adsorbs on the surface of the powder, thereby causing the powder to gray or possibly absorb and displace the cation with greater electronegativity in the powder (see, for example, U.S. Patent No. 189,411). This results in the light source not being able to illuminate with the same luminous flux after a certain period of time, that is, what the physical properties of the luminous flux itself would provide with other, primarily electrical, parameters. This phenomenon is described in, inter alia, GB 1 229 038 in connection with silicate type fluorescent lamps. It has also been suggested that to reduce mercury adsorption, it is advisable to reduce the excess silica in the phosphor. To this end, a special composition of zinc borate containing excess zinc oxide was added to the powder and heat-treated together, thus changing the structure and composition of the light bomb itself. This can be accomplished by the use of parameters that are quite complicated and very closely followed, and that the presence of zinc is also disadvantageous, as described in U.S. Patent No. 189,411.

To reduce the luminous flux properties of calcium halophosphate luminous fluxes, namely in U.S. Pat. However, this is also disadvantageous, as can be seen in the aforementioned patent application HU 189 411, since zinc impairs the stability of the phosphor against positively charged high energy mercury ions.

For example, compact fluorescents should avoid zinc-containing fluorescents.

To reduce the reduction in luminous flux, the coating of calcium halophosphate with a chemically "in situ" phosphate layer was further proposed in GB 1 191 974. Similarly, GB 1 343 250 proposes a chemically separated phosphate layer for silicate type phosphor.

With these methods of engagement, more or less success has been achieved. However, none of the methods sought to develop a treatment method to compensate for the initially negative charge on the surface of the fluorescent light, and even to provide a positive charge on the light bomb.

However, we have discovered that mercury adsorption can be most reliably avoided by saturating the surface of the phosphor with positively charged stable material. This eliminates the possibility that the fluorescent light on the inner surface of the bulb of the discharge light source and in contact with the discharge area will attract positively charged high energy mercury ions. In this way, the luminous flux of the discharge light source containing the composite light we recommend is not reduced or lessened.

In order to provide a positive charge on the surface of the fluorescent material, very finely ground, activator-free material with a small excess of cation relative to the stoichiometric amount is mixed with the fluorescent material. The discharge light source, in particular a fluorescent lamp, preferably a high wall load fluorescent lamp, is provided with this mixed material on the inner surface of its discharge lamp.

Mixing fluorescent light with inactive, non-luminous material is known in the art. These materials are either intended to provide a reliable connection between the light powder layer and the inner surface of the bulb, acting as an adhesive, or as having a UV-absorptive role, or even as a reflector of ultraviolet rays. In addition to the descriptions already mentioned, U.S. Pat. Nos. 3,310,418, 3,886,396 and GB 1,496,438, GB 2,082,618 and JP 49-18092B and JP 53-69483B disclose these. Patent Specifications. These sites include, but are not limited to, magnesium oxide, alumina, silica and calcium diphosphate.

Of course, these materials are always white, as they reduce the light of the light source the least. However, it has never been suggested in the literature that the inactive substance miscible with the phosphor should have a small excess of cation relative to the stoichiometric to offset the negative charge of the anion excess in the phosphor itself. To our knowledge, this is our realization. Of course, the charge of the inactive material we recommend with excess cation will be positive, so when mixed with the negatively charged luminescent material, it will bind to the negatively charged foci and thus block them from the mercury ion in the discharge chamber. Thus, it protects the light powder from the impact of mercury. This is particularly important when used in compact fluorescent lamps, where the above phenomena play a significant role in the discharge vessel. As such a positively charged activator-free material, we have found the alkaline earth metal diphosphate and tetraborate individually or in combination.

HU 202 333 Β

Based on our discoveries, we have developed an improved low-pressure mercury vapor discharge light source having a luminescent layer, a radiation-permeable bulb at a defined length, an ionizable and scintillating charge of noble gas and mercury within the jacket, and a lumen non-material, positively charged, activator-free, having an average particle size of luminescent material, preferably of 0.5-0.1 µm, and preferably of the formula M _i (P ₂ O ₇ ) _y (B ₄ O ₇ ) _z

M is Ca, Sr and / or Ba singly or in combination, y = 1 - zo <z <1 l, 05 (2y + z) <x <1.15 (2y + z) -, there is at least 0 , In an amount of 1% and up to 2% by weight, based on the total amount of luminescent material.

According to a preferred embodiment of our discharge light source, the inactive component is bonded to the surface of the luminescent particles in the layer.

According to a further preferred embodiment of the emitted light source, the luminescent layer comprises an alkaline earth metal phosphate as the luminescent material and a positively charged (Ca, Sr) _x P ₂ O 7 having a positive particle size of 0.5-0.1 gm, where x is 2.0 , May vary between 3

According to another preferred embodiment of our discharge lamp, the strontium chloropatite activated with Europium is the luminescent material and the average particle size is 0.50.1 µm Ca _x P ₂ O ₇ , where x is between 2.1 and 2.2

The present invention also relates to a composition for use in a mercury vapor discharge light source comprising a luminescent material and a positively charged inactive component. According to the invention, the composition has a positively charged content of 0.1 to 2% by weight, having an average particle size of less than the average particle size of the luminescent material, and preferably of the formula M _z (P ₂ O ₇ ) _y (B ₄ O ₇ ) _z

M is Ca, Sr and / or Ba individually or in any combination, y = 1 -z

Contains 0 <z <1 l, 05 (2y + z) <x <1.15 (2y + z) -, component.

Preferably, the composition comprises a diphosphate of the formula Ca 1 -Cb, wherein x is from 2.0 to 2.3, preferably from 2.1 to 2.2

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic representation of an interrupted image of a compact fluorescent lamp, and FIG. 2 is a schematic view showing a central view or a broken view of a fluorescent lamp for general lighting. partial longitudinal section.

The drawings and examples will illustrate the invention in more detail without, of course, limiting it.

Figure 1 shows a compact fluorescent lamp 1 according to an embodiment of the present invention. The discharge area is filled with noble gas and mercury. There are 2 luminescent layers on the inner surface of the bulb. The luminescent layer 2 comprises one or more constituent luminescent materials and also contains a positively charged inactive material.

First, we present the preparation of two possible inactive ingredients

Example 1

Preparation of Ca ₂₁ P ₂ O ₇

272 g of CaHPO ₄ and 20 g of CaCO _{3 are} mixed and homogenized until uniformly distributed, then placed in a quartz crucible and heated with the crucible in an oven at 1050 to 1100 ° C for 1 hour. It is cooled evenly to room temperature and wedged to the desired particle size.

Example 2

Ca) 65 (^ 207) 0 ^ (^ 4 (^ 7) 0 ^)

136 g of CAHPO ₄ , 139 g of B ₂ O ₃ and 65 g of CaCO _{3 are} mixed and homogenized until uniform. The mixture was heated uniformly to 900 ° C in a corundum crucible for 2 hours. After 2 hours, cool evenly and grind the cooled material to the desired particle size.

Example 3

Preparation of an Inactive Component Coating Material for Kckcn Illuminated Compact Fluorescent Lamp

Blue fluorescent phosphor activated strontium chloropatite. The inactive material is calcium diphosphate prepared in Example 1. 200 g of light powder were dispersed in 180 g of binder, which was a mixture of 1% nitrocellulose in butyl acetate and mixed with 14 g of 15% by weight of inactive substance in the same binder. The positive charge is 1% by weight based on the amount of phosphor.

This mixed fluorescent powder was coated with a 5 W compact fluorescent lamp with a film weight of 0.14 g. The fluorescent lamp was similar to that shown in Figure 1.

The fluorescent lamp thus prepared was burned and the intensity of light emitted was measured. In parallel, a blue fluorescent lamp of the same performance was fired, except that the fluorescent lamp contained no inactive component. This was the control fluorescent lamp. The patches are given in relative units and tabulated.

Intensity Intensity decrease (%) Oh 100h example fluorescent lamp 95 88 7.4 control fluorescent lamp 100 82 18.0

As can be seen in the example, the present invention can be used to reduce the reduction in intensity over the life of a fluorescent lamp, which is particularly important in compact fluorescent lamps.

HU 202 333 Β

Example 4

Preparation of a coating mass containing an inactive component and Ca-fluorochlorophosphate: Mn, Sb light powder for use in standard fluorescent lamps

400 g light powder

It was distributed in 360 g of aqueous binder and 27 g of a binder slurry containing 15% by weight of inactive material were mixed.

The inactive material is Ca _u Sr _lt P ₂ Cb.

The amount of inactive material is% by weight based on the amount of powder.

With the above coating mass, 36 W, 26 mm0 conventional fluorescent tubes were coated. (see Figure 2)

The finished fluorescent lamps were burned for 500 h. In parallel, a fluorescent lamp of the same power was burned but differed from the experiment in that it contained no inactive material. The intensity of the light emitted is given in relative units. The intensity of the control fluorescent lamp (containing no inactive material) is taken as 100. The results are tabulated.

Intensity in relative units % Decrease in intensity Oh 100h 500h 100h 500h Control fluorescent lamp is an example 100 97.0 93 3% 4% fluorescent lamp 99 97.0 95 2% 2%

The 500 h intensity decrease was calculated from the 100 h value.

It is clear from the example that the intensity values are still the same for 100 hours, but at 500 hours the difference for the fluorescent lamp according to the invention is clearly evident.

Example 5

Suitable for standard fluorescent lamps

400 g of halophosphate (4200K) light point (Ca-fluorochlorophosphate: Sb, Mn),

A suspension of 360 g of binder solution (11% nitrocellulose / butyl acetate), 15 g of inactive substance and a binder solution of the above composition was prepared. The inactive material may be represented by the formula Caj ^ (ΡιΟϋο / Β ,, Ο, ^).

With the above coating mass, 40 W 38 mm 0 fluorescent tubes were prepared.

The fluorescent tubes were co-fired with control tubes containing no inactive material. The intensity of light emitted after 0, 100, and 500 hours of burning is given in relative units. The intensity of the control fluorescent lamp at 0 hours was taken as 100.

Intensity in relative units % Decrease in intensity 0 100,500 hours 100,500 hours control tube 100 97.4 94.1 2.6% 3.4% Example 5 tube 98 97.4 96.4 0.6% 1.0%

The 500-hour intensity decrease was calculated from the 100-hour intensity. It can be seen that the fluorescent coated tubes containing the inactive material show intensities greater than 500 h, and the value of the decrease in intensity is significantly lower than that of the control tubes.

Although in this example only two fluorescent dyes are shown to have a positive effect on the positively charged activator-free material, this is also true for the multi-constituent luminescent material. We chose blue light powder in this example because it is the most sensitive to mercury adsorption, the easiest to shrink, so the most important thing here is to avoid mercury adsorption.

Once again, we emphasize that our inactive material must be positively charged in order for it to have a luminous flux reduction effect. However, the other well-known properties of the material described in the example are also present in the mixture, so they are not degraded by the excess cation present in the molecule.

The scope of the claims is within the scope of the claims, as one skilled in the art can, in addition to the example exemplified, create a variety of modalities if one is familiar with the inventive concept. We desire all these embodiments, that is, those which fall within the scope of our own inventive idea, e.g. alkaline earth metal aluminates or silicates, alone or in any combination with the above-mentioned materials, may also be considered as positively charged components.

Claims (6)

PATENT CLAIMS 1. A low pressure mercury vapor discharge light source, in particular a fluorescent lamp, preferably a high load fluorescent lamp, having a luminescent layer, a radiation permeable radiation at defined wavelength intervals, having an excitable and ionizable charge in a noble gas and mercury within the bulb, that in the luminescent layer (2), in addition to the luminescent material, there is a positively charged, activator-free, less than average particle size of the luminescent material, preferably 0.5-0.1 µm, of average particle size and preferably ösen, Μ / ^ / ΒΒ). - in which formula M is Ca, Sr and / or Ba, singly or in any combination, y = 1 - zo <z <1 l, 05 (2y + z) <x <1.15 (2y + z), at least 0.1 and up to 2% by weight based on the total amount of luminescent material. Low pressure mercury vapor discharge light source according to Claim 1, characterized in that the inactive component in the luminescent layer (2) is bonded to the surface of the luminescent material. Low pressure mercury vapor discharge light source according to claim 1 or 2, characterized in that the at least one luminescent material of the luminescent layer (2) has an average particle size (Ca, Sr) of apatite halophosphate and an inactive component of 0.5 µm. , P ₂ O ₇ , wherein x is from 2.0 to 2.3 Low pressure mercury vapor discharge light source according to Claim 3, characterized in that the luminescent material of the luminescent layer (2) is activated by europium. EN 202 333 rap strontium chloro-patatite and its inactive ingredient Ca.sub.O.sub.O., with an average particle size of 0.5 to 0.1 .mu.m wherein x is between 2.1 and 2.2. Composition of a luminescent material and an inactive component for a mercury-emitting light source, characterized in that the inactive component has a positive charge of 0.1-2% by weight based on the total amount of the luminescent material, less than the average particle size of the luminescent material, preferably 0.5-0.1 of average particle size, activator-free, and preferably of the formula 10 in which M represents Ca, Sr and / or Ba, individually or in any combination, y = 1-z o2 z <1.05 (2y + ζ) <x <1.15 (2y + z) -. 6. The composition according to claim 5, wherein the activator-free ingredient is diphosphate of the formula Ca2Oj, wherein x is 2.0 and It is comprised between 2.3 and preferably between 2.1 and 2.2.