KR940007648B1 - Fluorescent lamp - Google Patents

Abstract

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Description

Low pressure mercury vapor discharge lamp

BRIEF DESCRIPTION OF DRAWINGS Fig. 1 is a diagram schematically showing the structure of a parody cage of a blow-off powder charge measuring apparatus for measuring the charge amount of a fluorescent substance of the present invention.

2a is a model diagram of a carrier powder.

2b is a model diagram of a state in which a carrier powder and a sample for measurement are mixed.

3 is a diagram showing a charging sequence of a phosphor using various carrier powders.

4 is a characteristic diagram showing an example of a correlation between particle size and charge amount.

5 is a correlation diagram between the charge amount of an inorganic compound and the electronegativity measured by a blow-off charge measuring device.

Fig. 6 is a contrast diagram illustrating the relationship between the charge amount values when free bis or reduced iron powder is used as a carrier by the blow-off method.

7 is a diagram showing a structural example of a low-pressure mercury vapor discharge lamp according to the present invention.

8 is a diagram showing another structural example of the low-pressure mercury vapor discharge lamp according to the present invention.

9 is a diagram showing another structural example of the low-pressure mercury vapor discharge lamp according to the present invention.

FIG. 10 is an explanatory diagram showing the charge amount with respect to iron powder when reducing iron powder is used as a carrier for each sample by a blow-off method. FIG.

FIG. 11 is an explanatory diagram showing the charge amount with respect to iron powder when reducing iron powder is used as a carrier for each sample by a blow-off method. FIG.

12 is a characteristic diagram showing the relationship between the luminous flux ratio and the lighting time of a fluorescent lamp after day and night lighting.

13 is a characteristic diagram showing the relationship between the luminous flux ratio of a fluorescent lamp after day and night lighting and the charging tendency of the phosphor.

Fig. 14 is a characteristic diagram showing the relationship between the luminous flux ratio of the fluorescent lamp and the charging tendency of the fluorescent substance after 5 minutes of lighting.

FIG. 15 is a characteristic diagram showing the relationship between the luminous flux ratio of the fluorescent lamp and the charging tendency of the fluorescent substance after 5 minutes of lighting. FIG.

Fig. 16 is a characteristic diagram showing the relationship between the luminous flux ratio and the lighting time of a fluorescent lamp.

17 is a characteristic diagram showing the relationship between the luminous flux attenuation rate of a fluorescent lamp and the charging tendency of the phosphor.

18 is a characteristic diagram showing the relationship between the luminous flux decay rate of a fluorescent lamp and the charging tendency of a phosphor.

19 is a characteristic diagram showing the relationship between the light flux ratio and the lighting time of a conventional fluorescent lamp.

* Explanation of symbols for main parts of the drawings

1: parody cage 2: iron

3: nozzle 4: powder of sample

5: carrier powder 11, 15, 17: glass tube

12: clasp 12a: terminal lighting circuit

12b: power case 12c: insulation board

13, 16, 18: low pressure mercury vapor discharge lamp

14: phosphor

The present invention is characterized in that blackening does not occur during lighting and the rate of decrease of luminous flux is small A low pressure mercury vapor discharge lamp with excellent) characteristics.

Low pressure mercury vapor discharge lamp (fluorescent lamp) is a light source that is widely used in general lighting, such as a light source for OA devices, a pixel light source for a large screen, a backlight of a liquid crystal display. This is because the power supplied to the low pressure mercury vapor discharge lamp is converted into a highly efficient radial direction.

The low-pressure mercury vapor discharge lamp is configured such that a glass gas in which a fluorescent layer is formed on the inner wall is filled with a mixed gas containing mercury and one or two or more rare gases, and a positive light discharge is generated in the mixed gas.

The discharge is usually maintained by supplying electrical energy to the mixed gas through two electrodes. Ultraviolet rays are mainly generated by this discharge, and most of them have wavelengths of 185 nm and 254 nm, and the intensity ratio of 185/254 is usually 0.2 to 0.4. This ultraviolet light is converted into long wavelength radiation by a fluorescent layer formed on the inner wall of the glass tube. These wavelengths are obtained from near ultraviolet to visible-near infrared, depending on the kind of phosphor particles contained in the fluorescent layer. One of the most common types of low pressure mercury vapor discharge lamps is the 40W type, with a full length of 1200 mm and an inner diameter of a glass tube of about 37 mm. The tube wall load of this lamp is about 300 W / m ² .

The glass tube is not limited to a straight tube, but may be configured in a circular shape, a U shape, a saddle shape, or the like, and in recent years, miniaturization has progressed and the shape has become complicated.

On the other hand, according to making a fluorescent lamp high color rendering etc., the three wavelength fluorescent lamp using the fluorescent substance which shows blue, green, and red light emission which has a light emission spectrum distribution of a relatively narrow band is also known. In the case of the three-wavelength fluorescent lamp, since the ratio of the green component light flux to the total light flux (light emission output) is high, the characteristics of the green light emitting phosphor are important. Such phosphors include, for example, green luminescent clay aluminic acid, silicic acid, phosphate phosphors, reconstituted with cerium and terbinium, rare earth boric acid, silicic acid, phosphate phosphors, rare earth phosphate phosphors, rare earth aluminic acid, boron, phosphate Phosphors and the like are known.

However, as described above, the tube wall load tends to be higher as the high tube wall load and the miniaturization of the low pressure mercury vapor discharge lamp progress. Several low-pressure mercury vapor discharge lamps with fairly high pipe wall loads have been disclosed, for example in JP-A-2109898. However, lamps having relatively high pipe wall loads have disadvantages such as lower lamp efficiency, higher luminous flux deterioration rate, higher blackening of the lamp, and higher luminous flux immediately after the lamp is turned on. .

Japanese Patent Application Laid-Open No. 54-42874 discloses a lamp using a phosphor particle for forming a phosphor layer having a low rate of decrease in luminous flux, in which a bond of positive ions of the phosphor particle has an electronegativity of 1.4 or less. However, under the unique conditions as described in the above publication, the rate of decrease of the luminous flux cannot actually be explained.

On the other hand, the cause of tube blackening, spot blackening, and blackening of the low-pressure mercury vapor discharge lamp may also be affected by filament, cathode, and organic binder residues. There is also the possibility of contaminating the phosphor particles (phosphor layer).

In addition, in the conventional low pressure mercury vapor discharge lamp having a high pipe wall load, even if the lamp manufacturing method or structure is the same, the type of phosphor particles (fluorescent material), and even the same type of phosphor particles, the degree of blackening according to the production route, etc. There is a drawback that irregularities tend to occur in quality, such as a difference may occur. In particular, in the case of the rare earth green light-emitting phosphor, color phenomena due to contamination by mercury or a compound thereof are more likely to occur than the red light-emitting phosphor, and the three-wavelength fluorescence in which the state of the green light-emitting phosphor greatly affects its characteristics. In the lamp, there is a difficulty in that the occurrence of the above problems becomes remarkable.

As described above, the conventional low pressure mercury vapor discharge lamp having a high pipe wall load, that is, a compact and small low pressure mercury vapor discharge lamp, is liable to cause blackening with low luminous efficiency, has a high rate of decrease in luminous flux, and It has the disadvantage of late rise. In addition, these defects are prone to non-uniformity and poor reproducibility in terms of quality.

The reason why the increase in the luminous flux is late is that adsorption of mercury to the phosphor is considered. In particular, as the wall load increases, the probability of mercury atoms recombining with electrons on the surface of the phosphor particles of mercury ions increases as the current density increases. When the mercury atom is adsorbed in the phosphor film during the lamp lighting and the light is turned off, the mercury adsorbed is first released, and then the mercury, which is agglomerated at the coldest part of the lamp, is gradually released, depending on the mercury vapor pressure in the tube. The speed of light rises. FIG. 19 shows the relationship between the luminous flux ratio and the lighting time. The curve (a) shows the rise of the luminous flux of the straight-type 40W type with relatively low tube wall load of the lamp. The curve (b) shows the wall wall load 500W using the three-wavelength light emitting phosphor. / m ² or more luminous flux rise is indicated respectively. In FIG. 19, part X indicates when mercury adsorbed to the phosphor layer is released, and part Y indicates when mercury, which is agglomerated at the coldest part of the lamp, is gradually released.

The present invention has been studied to cope with the above-described problems, and an object of the present invention is to provide a low-pressure mercury vapor discharge lamp with a suppression of blackening under a high pipe wall load and a small rate of decrease in luminous flux.

The low pressure mercury vapor discharge lamp of the present invention is a light transmissive glass tube filled with a sealing gas containing mercury and a rare gas, a fluorescent layer containing phosphor particles formed on the inner wall surface of the light transmissive glass tube, and a positive light discharge in the sealing gas. And a means for maintaining the phosphor layer, wherein the phosphor particles forming the fluorescent layer have a tendency to be charged on the negative side of the metal oxide having an electronegativity of metal ions of 7.0 and a metal oxide having an electronegativity of 11.8. It is characterized by being in the positive (+) side more.

Specifically, the phosphor particles forming the phosphor layer are charged with an electrostatic charge of 3.0 μC (micro coulombic) or less per 1g or when the soda-lime glass vis with a particle size of 200 μm to 500 μm is contacted, or a particle size of 44 μm to 74 μm. To charge more than -0.5 μC per gram upon contact with the reduced iron powder of will be.

Moreover, this invention is especially effective with respect to the high load type low pressure mercury discharge lamp whose pipe wall load is 500-2000 W / m <2>. That is, in the low-pressure mercury vapor discharge lamp, especially in the high load type, it was found that the rate of blackening caused by mercury adsorption correlated with the tendency of charging the surface of the phosphor particles (including the treating agent) constituting the fluorescent layer. Is made in this respect.

In general, when two kinds of materials come into contact, the same amount of positive and negative charges are generated on the surface of each material. The positive charge generating material here tends to be positively charged and the negative charge generating material is said to be negatively charged. The charging sequence is referred to as a charging sequence in which charging tendencies are examined and the materials charged positively to any material are arranged at the highest level and the materials charged negatively to any material are arranged at the lowest level. Some of these charging sequences are known for natural or organic matter.When two kinds of substances in the sequence are contacted, the sequence is charged positively and the sequence charged negatively. The higher the sequence of the above substances, the stronger the tendency to charge the tablet.

For example, it is generally known that manganese-activated zinc silicate phosphors (Zn ₂ SiO ₄ : Mn) are prone to blackening. Among the phosphors for lamps, Zn ₂ SiO ₄ : Mn was found to have a particularly strong tendency to negatively charge. On the other hand, mercury filled in the transparent glass tube reacts with gases (such as CO ₂ ) or impurities emitted from the constituents in the lamp to form HgO. It was found that HgO, the mercury compound, showed a tendency to be positively charged more strongly than Zn ₂ SiO ₄ : Mn. Therefore, when Zn ₂ SiO ₄ : Mn adsorbs HgO, negative and positive charges are generated on the contact surfaces of Zn ₂ SiO ₄ : Mn and HgO, respectively, and it is difficult to separate them by the electrostatic attraction. Is thought to occur. In other words, it is thought that blackening of the fluorescent layer is more likely to occur as the difference in charging tendency is larger than that of HgO. Such a thing is confirmed also by the analysis result of a deposit. In addition, the composition ratio of ZnO and SiO ₂ in Zn ₂ SiO ₄ : Mn is a stoichiometric composition of 2: 1, but in the ordinary one, this ratio is not exactly 2: 1, and ZnO is 1.5 to SiO ₂ . Often takes a value of 2.2.

Zn ₂ SiO _4: Mn phosphor is generally when the ZnO that tends to convey stronger forces such as the composition ratio of not more than 2.0 with respect to the SiO ₂ indicates a tendency to negatively charged is much stronger, while the ZnO is more than 2.0 with respect to SiO ₂ On the contrary, the side war tends to weaken. Thus, it was found that it is difficult to judge the charging characteristics of the material only by the general chemical formula of the phosphor. In addition to such deviations from the stoichiometric composition, there are various factors that give a nonuniformity to the evaluation results of the charging characteristics.

In the low-pressure mercury vapor discharge lamp of the present invention, the phosphor particles (materials) forming the fluorescent layer have a negative charging tendency on the negative side of the metal oxide having an electronegativity of metal ions of 7.0 and a metal having an electronegativity of 11.8. Particle size 200 µm ~ by a specific measuring method using a blow-off powder charging measuring apparatus using a parody cage, which is phosphor particles (including those that are processed in any form) on the side of the oxide. Phosphor particles having a charge amount of 1 g or less determined to be 3.0 μC or less upon contact with 500 μm of soda-lime glass bis or charged amounts per 1 g exceeding −0.5 μC when contacted with reduced iron powder having a particle size of 44 μm to 74 μm By using the fluorescent substance particle | grains judged to be, the generation | occurrence | production of blackening is assuredly suppressed by the outstanding reproducibility.

In this invention, the measuring method of the charging characteristic (charging tendency) of the fluorescent substance particle which forms a fluorescent layer is as follows.

1, a wire mesh 2 is provided at one end of the parody cage 1 of the blow-off powder charging measuring apparatus, and a nozzle 3 is provided at the other end. Then, the sample powder 4 having a smaller particle diameter than the mesh nose of the wire mesh 2 and the carrier powder 5 having a larger particle size than the nose are mixed and placed in the cage 1, and the compressed gas (eg Nitrogen gas). Only the sample powder 4 passes through the mesh 2 and is scattered out of the cage 1. At this time, the carrier 5 remaining in the cage 1 is left with the same amount of charge Q as the sample powder 4 takes, so the capacitor C and the voltage V of the capacitor 6 connected to the cage 1 remain. And Q = C · V. When the weight m of the scattering sample powder 4 is used, the amount of powder charge per unit weight is obtained at -Q / m (C / g).

As the carrier powder 5, the powder which passed through 400 mesh normally is used. Here, a carrier with a particle size (soda-lime glass vis) that does not pass through 200 mesh is used. As the sample powder 4, phosphor particles (powder) smaller than 400 mesh were used.

Here, an example of the manufacturing method of a measurement sample is demonstrated.

20 g of carrier powder and 0.2 g of fluorescent powder are precisely weighed with a chemical balance and put into agate induction, and mixed in a floating rod without much force. Next, the whole amount is placed in a wide bottle of 100 ml polyethylene, mixed for 5 minutes in a mixer (shaker) to prepare a sample. 0.2 g of the mixed powder of the carrier powder and the phosphor powder is accurately weighed to obtain a sample for measuring the blow-off powder charge amount. The models of the measurement sample (after carrier mixing) for blowing off carrier powder are shown in FIG. 2A and FIG. By mixing the carrier powder 5 (FIG. 2A) and the fluorescent powder, it becomes the measurement sample for blow-off (FIG. 2B) in which the phosphor powder 4 was carried on the carrier powder 5 surface.

Below, the evaluation result of the charging characteristic of various fluorescent substance by a blow-off powder charge quantity measuring apparatus is demonstrated. First, the charging sequence of the main fluorescent substance was determined using various carriers. The result is shown in FIG.

The charging sequence means that the upper material is charged positively and the lower material is charged negatively when any two kinds of materials are contacted. In FIG. 3, it is predicted that the phosphor particles (powder) have less adsorption of HgO at the position closer to HgO, and that the phosphor particles (powder) have more adsorption of HgO at the position away from them. However, FIG. 3 is only a mere sequence, and since it does not show a difference in the quantitative charging tendency of how much blackening occurs when it actually falls to an extent, it cannot be known unless it is executed.

Subsequently, the contact charge amount of the main phosphors was measured using the above-described particle diameters of 200 μm to 500 μm soda-lime glass vis (made by Toshiba Barodeni Co., Ltd., GB series glass vis). It was found that the battery was charged and had a charge of 0.1 to 3 µC / g. On the other hand, it was also found that there was a relatively little charge against (-). In this measurement, however, it was found that an error occurred in the measured values due to differences in the particle diameters of the phosphor particles or due to variations in the quality between the routes due to differences in the manufacturing process and the like, and deviations from the stoichiometric composition described above. Among these factors, the factor of the particle size of the sample powder (phosphor) has the greatest difference since the surface area has a large difference. 4 shows an example of the relationship between the charge amount and the particle size.

Therefore, in the present invention, the particle size of the phosphor sample powder is normalized and measured. Specifically, in the present invention, the particle diameter is unified to 5 ± 2 μm in measuring the charge amount of the phosphor. The results measured under these conditions are shown in Table-1.

TABLE 1

5 shows the measurement result of the charging tendency of simple oxides containing HgO by the blow-off powder charging measuring apparatus (Journal. Of Electrochemical. Society, Vol. 133, p. 842 (1986). Reference). In this case, since the enemy of the amount of charged particles and the specific gravity of each oxide of the fine particle oxide having a uniform particle diameter is taken as the vertical axis, the value of the amount of charge is largely displayed.

As can be seen from FIG. 5, the electric charge by the above measurement is the electronegativity of the metal ions constituting the oxide (X ₁ = (1 + 2z) X ₀ … (z is a valence) X ₀ is the electronegativity of the element of the poring and also showing a display) and a very good correlation, the smaller the X ₁ and the tendency of the positively charged, as the X ₁ tends to be negatively charged. HgO may also nuggets good absorption of phosphor particles because of the degree of charging tendency from Y ₂ O ₃ has devised a well-adsorbed fluorescent material containing as a main component, HgO trend away from the charging as Y ₂ O _3. As a result of experimentally confirming how much a difference in charging tendency is allowed, it is possible to suppress the occurrence of blackening by using a phosphor having a charge amount of 3 μC / g or less according to the measuring method. If the charge amount exceeds 3 µC / g, the difference in charge amount with HgO becomes too large as described above, and the occurrence rate of blackening is high. More preferable charge amount is in the range of 0.5 µC / g to 2.5 µC / g.

Moreover, in the above, although the charging quantity of various fluorescent substance was measured using the glass vis of predetermined particle diameter as a carrier, the same result was shown also when the reduced iron powder of 44 micrometers-74 micrometers of particle diameters was used as a carrier. However, the preferable charge amount in this case was about -0.5 microC / g-about 2.5 microC / g.

5 shows the charging tendency of the simple oxide particles or the charging tendency positions of the plate-like material instead of the particles. That is, the charging tendency position of a plate-like substance can be known by inclining a plate-like substance, rolling various oxide particles on this inclined surface, and irradiating the charging code of these particles with a receiving plate. Thus, the charging tendency position of metal plates, such as nickel, chromium, and tantalum which were obtained in this way, was shown in FIG. Further, by inclining the metal plate on which the charging tendency position is confirmed, the phosphor particles are rolled on the inclined surface, and the charging sign of these phosphor particles is irradiated with the receiving plate, so that the charging tendency can also be compared with the phosphor particles having different particle diameters in FIG. In the blow-off powder charging device, the charge amount of 0.5 μC / g to 2.5 μC / g obtained from 5 ± 2 μm phosphor particles using glass bis with a predetermined particle diameter as a carrier is more positive than nickel tantalum in FIG. It means the charging tendency of the negative side rather than a slightly higher position, and this value is in the range of 7.0-11.8 as the value of the electronegativity of the metal ion of FIG.

Specific examples of the phosphor (phosphor particle) used in the present invention include BaMg ₂ Al ₁₆ O ₂₇ : Eu ²⁺ , Sr ₁₀ (PO ₄ ) ₆ Cl ₂ : Eu ²⁺ , (Sr, Ca) ₁₀ (PO ₄ ) ₆ Cl ₂ : Eu ²⁺ , (Sr, Ca, Ba) ₁₀ (PO ₄ ) ₆ Cl ₂ : Eu ²⁺ , (Ba, Ca, Mg) ₁₀ (PO ₄ ) ₆ Cl ₂ : Divalent europium such as Eu ²⁺ Activated blue phosphor; La ₂ O ₃ 0.2SiO ₂ 0.9P ₂ O ₅ : Ce, Tb, LaPO ₄ : Ce, Tb, Y ₂ SiO ₅ : Ce, Tb, CeMgAl ₁₁ O ₁₉ : Tb, Zn ₂ SiO ₄ : Mn Green phosphor Y ₂ O ₃ : Eu ³⁺ , YVO ₄ : Eu ³⁺ , Y (P, V) O ₄ : Eu ³⁺ , Y ₂ O ₂ S: Eu ³⁺ and other trivalent europium-activated red phosphors, etc. Rare earth phosphors are exemplified, and those satisfying the above charging characteristics are used. In addition, a substance obtained by mixing the blue phosphor, the green phosphor and the red phosphor so as to have a color temperature of the emission color of 2800K to 1000K may be used, and in this case, the charging characteristics are also satisfied.

In addition, considering the charging characteristics of the inorganic compound shown in FIG. 5, inorganic compounds in which HgO and charging characteristics (sign and charge amount) are approximate, for example, oxides such as Al ₂ O ₃ , Ca ₂ P ₂ O ₇ , Charging characteristics can be controlled within the scope of the present invention by attaching alkaline earth metal compounds such as Sr ₂ P ₂ O ₇ and Ba ₂ P ₂ O ₇ to the surface of the phosphor particles.

When preparing the fluorescent substance particle | grains which adhered the inorganic compound to such a surface, it is good to mix so that an inorganic compound may exist in the range of 0.01-5.0 weight%, Preferably it is 0.01-3.0 weight%. Table 2 shows the measurement results (measured by the blow-off powder charging measuring device described above) of the phosphor having the above-mentioned inorganic compound attached (mixed) to the surface. In Table-2, for example, the sample 17 is the surface of the sample 7 and the sample 28 is the surface treatment of the sample 6, respectively. Compared with the measurement results, it can be seen that the surface-treated phosphors have different characteristics.

TABLE 2

In addition, the phosphor particles in the case where each measurement of the glass bis or reduced iron with respect to the thus prepared sample by MgO or SiO ₂ surface with adhered (coating) of 0.1 to 0.5% by weight based on the (Y ₂ O ₃ Eu) as the carrier The charge amount was shown to be the same as the city of FIG. In other words, the measured value also varies depending on the carrier.

Here, as the inorganic compound adhering to the surface of the phosphor particles, a metal oxide selected from the group of MgO, CaO, SrO, BaO and ZnO is more preferable. The reason is that the electronegativity of the metal ions is 7 or less (positive charge) and the charging tendency of the surface is in the positive direction in an appropriate range than HgO, so that the charging tendency of the surface of the phosphor can be shifted in the positive direction with a small amount of adhesion. By this, reaction with HgO can be prevented and blackening can be suppressed more effectively. In addition, the inorganic compound to be attached is selected in consideration of factors other than the charging tendency such as chemical stability, absorption of ultraviolet rays or light emission, and generally has an electronegativity such as alkaline earth elements, rare earth elements containing yttrium, aluminum or gallium, etc. Metal oxides of 11 or less can be positively charged against iron, and metal oxides with an electronegativity of 11, such as titanium, tantalum and phosphorus, can be negatively charged against iron. Of course, these can also be used in a mixture.

The adhesion amount of these inorganic compounds to the surface of the fluorescent particles is selected in the range of 0.01 to 3.0% by weight based on the phosphor particles. That is, when the adhesion amount is less than 0.01% by weight, the control effect of the charging tendency is not sufficiently obtained, and the luminous efficiency of the phosphor exceeding 3.0% by weight tends to decrease.

As described above, in the low-pressure mercury vapor discharge lamp, especially a high load lamp having a pipe wall load of 500 to 2000 W / m 2, the charging property of the fluorescent material constituting the light emitting layer is 200 g / 500 μm in contact with glass vis. By having an electrostatic charge of 3.0 µC or less, blackening by adsorption of mercury can be surely suppressed with excellent reproducibility.

EXAMPLE

Hereinafter, embodiments of the present invention will be described.

Example 1

First, a phosphor powder selected from the phosphors coated with inorganic compounds on the phosphors of Sample Nos. 1 to 15 shown in Table -1 and the phosphors of Samples 16 to 25 shown in Table -2 is added to a solvent in which a binder is dissolved. It disperse | distributed and produced the slurry, respectively.

Next, as shown in FIG. 7, the slurry containing the fluorescent substance was applied to the inner wall surface of the straight organic tube 11, and the baking and exhausting processes of removing the binder after drying were performed. The tube-type low pressure mercury vapor discharge lamp 13 having a diameter of 25 mm, an enema 1200 mm, and a clasp 12 having a lighting circuit at both ends thereof is filled with a sealing gas and sealed through an aging process. The characteristics evaluation which produced each and performed later was performed. 14, 14 shows a phosphor layer.

Example 2

U-shaped low pressure mercury vapor discharge lamp having a tube wall load of 1000 W / m 2, an enema 410 mm, and a diameter of 20 mm using a U-shaped glass tube 15 as shown in FIG. 8 in the same process using the same fluorescent material as Example 1 16) was produced and referred to a characteristic evaluation described later.

Example 3

A compact low pressure mercury vapor discharge lamp 18 having a pipe wall load of 1500 W / m 2 using the curved glass tube 17 as shown in FIG. 9 by the same process using the same fluorescent material as in Example 1 was prepared. It referred to the characteristic evaluation to mention later. In the figure, 12a is an electronic lighting circuit, 12b is a power case, and 12c is an insulating board.

The low-pressure water in each of the above embodiments was turned on by high load, i.e., 30 seconds, by the life test (see JIS 7601) specified in JIS to investigate the occurrence of blackening by adsorption of Hg during identification (operation process) of the steam discharge lamp. Forced ON test by OFF cycle. In this 30-second ON-OFF cycle test, the normal 1000-2000 hour lighting test is accelerated to almost 10 hours.

Evaluation of the degree of blackening by adsorption of mercury was made into 10 points that there was no blackening immediately after lighting (0 hours), and the score was scored in 10 steps from a practical guernsey about lighting for predetermined time. It is also pointed out that blackening has occurred in 0 hours of the evaluation time and that blackening has already occurred before lighting, that is, at the stage of aging.

An approximate standard is shown below.

10 to 9 points… No problem.

8 to 7 points… It is possible to use, but there is a problem in appearance.

6 to 5 points… Poor appearance, light speed decreases.

4 to 3 points… Poor appearance, hard to light.

2 to 1 points… No light, not available.

The degree of blackening was determined based on the same criteria as described above. The results are shown in Table-3, Table-4 and Table-5.

In addition, each comparative example in the table shows the charging sequence with the fluorescent substance or HgO of the incident tendency among the fluorescent materials of Sample Nos. 1 to 13 shown in Table-1 and the fluorescent materials of Samples 16 to 25 shown in Table 2, respectively. The fluorescent material having a large difference of was selected, and the low-pressure water vapor discharge lamp produced under the same conditions as in the above example was also evaluated for the degree of blackening, and the results were also shown in Tables 3, 4, and Table- We display in addition to 5.

TABLE 3

TABLE 4

TABLE 5

As apparent from Tables 3, 4, and 5, low pressure mercury vapor discharge lamps using fluorescent materials having a tendency of negative charge or fluorescent materials having a large difference in charge sequence with HgO showed that blackening was easy to occur. The low pressure mercury vapor discharge lamp using the fluorescent material whose charging characteristics were controlled, that is, the charging characteristics were within the scope of the present invention, suppressed the occurrence of blackening over a long period of time, and as a result, the rate of decrease of the luminous flux can be appropriately adjusted. It can be seen.

Example 4

1.10 g of magnesium nitrate [Mg (NO) ₃₂ ] is dissolved in 200 cc of distilled water. Rare earth aluminic acid, silicic acid, and phosphate green light emitting phosphors [(Laa _0.06 Ce _0.25 Tb _0.15 ) ₂ O ₃ . 0.003Al ₂ O ₃ . 0.0005 SiO ₂ , 1.003P ₂ O ₅ ]] is added and stirred well.

The pH is adjusted to the alkaline region with ammonia water [NH ₄ OH] with stirring. The result is a gelled substance of magnesium hydroxide. After stirring is sufficiently performed under this condition, the mixture is washed several times with distilled water, and the suspension is suction filtered. The obtained filter cake is dried at 3000 degreeC-400 degreeC.

The phosphor particles thus obtained may have adhered surfaces of 0.3 wt% MnO fine particles.

Subsequently, using this green light emitting phosphor, a 4W fluorescent lamp, FL4 (15.5 mm ø, wall wall load 1100 W / m 2) as shown in FIG. 7 was produced according to a conventional method, and the initial light output and the light output after 1000 hours of lighting and The coloring (light dark brown) state of fluorescence was measured and evaluated. The fluorescent lamp 13 is constituted by depositing a fluorescent film 14 on the inner surface of the glass bulb 11 and sealing a predetermined input discharge gas, that is, a rare gas such as mercury and argon and a mixed gas. An electrode (not shown) is placed at both ends of the glass bulb 11 and the fluorescent film 14 emits light by being excited by applying a predetermined voltage to the electrode via the clasp 12. On the other hand, the same fluorescent lamp was fabricated by using the rare earth aluminic acid, silicic acid, and phosphate green light emitting phosphors, which were revived with the cerium and the terbium used in the above examples, as a comparative sample, without being coated with a metal oxide, and the characteristics thereof were measured under the same conditions as in the examples. did. In addition, the measurement result showed the relative value when the initial emission output and the light emission output after 1000 hours of lighting were made the value of the fluorescent substance of a comparative sample 100% similarly. The degree of coloration of the bulb of the fluorescent lamp was 10 points at the highest, and the smaller the coloration was, the higher the score was.

The luminous output after 1000 hours of lighting was 110% for the phosphor of the comparative sample, and the degree of coloring of the bulb of the fluorescent lamp was 6.0 for the phosphor of the comparative sample, whereas the phosphor of the example was high at 9.0, and the quality was improved. This was achieved. Also, no significant decrease was observed in the initial luminescence output, and the value was maintained almost equal to that of the phosphor of the comparative sample.

Example 5

1.0 g of zinc oxide [ZnO] fine powder (with a particle diameter of 0.05 μm and suspended in 200 cc of pure water. Sustained rare earth silicic acid, boric acid, and phosphate-activated green light-emitting phosphor [(La _0.04 Ce _0.45 Tb _0.15 ) ₂ 100 g of O ₃ , 0.001 SiO ₂ , 0.988 P ₂ O ₅ , 0.0005 B ₂ O ₅ ], followed by stirring sufficiently, and then 0.1 g of acrylic emulsion and 0.05 g of polyacrylic acid ammonium were added sequentially and uniformly dispersed. The filter cake obtained by suction filtration of the suspension was then dried at around 120 ° C. The phosphor particles thus obtained were coated with 1.0 wt% ZnO mirin layer.

Using this green light emitting phosphor, a fluorescent lamp was produced in the same manner as in Example 4, and the characteristics were identified and evaluated under the same conditions. The results are shown in Table-6.

In addition, the comparative sample in a table | surface is the measurement result of the fluorescent lamp produced on the conditions similar to the Example except not performing metal oxide fine particle adhesion.

TABLE 6

[Examples 6-16]

As shown in Table 6, the distillation and adhesion concentrations of the green light emitting phosphor and the metal oxide adhering to the surface were changed, and green light emitting phosphor was prepared in the same manner as in Example 4. In addition, a fluorescent lamp was produced using the obtained green light-emitting phosphor, and the characteristics were evaluated in the same manner. These results are also shown in Table-6.

[Comparative Examples 3 and 4]

The green light emitting phosphor was produced in the same manner as in the case of Example 4 except that phosphors having the same composition as those used in Examples 4 and 7 were used, respectively, and the deposition amount of the metal oxide fine particles was outside the scope of the present invention. Moreover, the fluorescent lamp was produced using the obtained green light emitting fluorescent substance, and the characteristic evaluation was performed similarly.

As apparent from Table 6, according to the load-type fluorescent lamps (500 W / m 2 or more) using the phosphors according to the embodiments, the initial emission output was kept about the same as the conventional one, while suppressing the decrease in the emission output after long-time lighting and the fluorescence It can be seen that the coloring phenomenon of the lamp can be reduced.

Example 17

100 g of a red light-emitting flow-activated yttrium-oxide fluorescent substance for lamps having an average particle diameter of 4.2 µm was suspended in distilled water, and 1 ml of a solution of 1% by weight of magnesium oxide (manufactured by Baikosuki Co., Ltd., Vicarox M120) was added to distilled water. The mixture was stirred for at least 30 minutes, filtered by suction, and dried at 125 ° C. Moreover, this is calcined on condition of 350 degreeC and 5 hours in air.

The obtained phosphor was observed with a scanning electron microscope to confirm that the colloidal particles were well dispersed and adhered to the surface of the phosphor particles.

Further, 0.4 g of the obtained phosphor and 20 g of reduced iron powder (TEFV) having a particle diameter of 74 µm to 44 µm were mixed, and the contact charge amount per phosphor of phosphor relative to iron was +0.94 µC / g by a blow-off device. .

The obtained phosphor was dispersed in a solvent containing a binder and in which a nitro cellulose binder was dissolved to prepare a slurry. Next, a slurry containing the above-mentioned phosphor is applied to the inner wall of the tube-shaped glass tube with an inner diameter of 10 mm so as to have a constant film thickness, and after baking, a baking process for removing the binder is carried out, followed by filling with mercury and a sealing gas, and having a gap length of 300 mm. A straight-line low pressure mercury vapor discharge lamp was produced. In addition, the amount of mercury remaining in the lighting was agglomerated into the capillary tube which is the coldest part of the lamp.

The luminous flux of the lamp reached a square value of about 30 seconds after lighting. Moreover, it was 90% when the luminous flux for 300 hours after lighting was measured with respect to the initial value, and the luminous flux maintenance factor was calculated | required.

Example 18

Instead of the magnesium oxide of Example 17, 0.2 g of zinc hydroxide colloid produced by adding 0.2 mol / l aqueous solution of ammonium and 0.1 mol / l zinc sulfate was attached to the particle surface of the red light-emitting fluorescent substance. By the drying in the same order as in Example 17, the pure zinc oxide colloid was changed to a zinc oxide colloid.

The amount of contact charge of the phosphor to iron was measured in the same manner as in Example 17, and then a fluorescent lamp was produced in the same manner as in Example 17, and the results are shown in Table-7 in the same manner as in Example 17.

[Comparative Example 5]

A fluorescent lamp was produced in the same manner as in Example 17 using a flow path-activated yttrium oxide phosphor which did not adhere a metal oxide to the particle surface. The contact charge amount of the phosphor to iron was 0.3 µC / g, and the light flux retention was 87%.

[Comparative Examples 6 and 7]

Fluorescent lamps were prepared in the same order as in Example 17 with respect to a sample in which silicoid (OX-50, OX-50), instead of the magnesium oxide of Example 17, was attached to the particle surface of the eurolium-activated yttrium oxide phosphor. Made.

And the contact charge quantity of the fluorescent substance and the characteristic of the fluorescent lamp were evaluated by the method similar to the case of Example 17. The results are shown in Table-7.

In addition, in the fluorescent lamps of these comparative examples, it took 5 to 6 minutes for the luminous flux to reach a normal value after lighting.

[Examples 19-21]

Magnesium oxide or zinc oxide was affixed on the surface of the green luminescence manganese activating zinc silicate fluorescent substance particle | grains for lamps of average particle diameter 5.7 micrometers in the same procedure as the case of Examples 17-18. Using these phosphors, a fluorescent lamp was produced in the same order as in Example 17, and the contact charge amount of the phosphor and the characteristics of the fluorescent lamp were evaluated in the same manner.

The results are shown in Table-7.

Example 22

A sample in which 0.5 wt% of magnesium oxide colloid was initially attached to the surface of green luminescent manganese-activated zinc silicate phosphor particles for lamps was prepared, and then 0.2 wt% of silica rolloid was attached to this sample. Using this phosphor, a fluorescent lamp was produced in the same order as in Example 17, and the contact charge amount of the phosphor and the characteristics of the fluorescent lamp were evaluated in the same manner. The results are shown in Table-7.

[Comparative Examples 8 and 9]

A fluorescent lamp was produced in the same procedure as in Example 17 for a sample in which a green light-emitting manganese-activated zinc silicate phosphor and a silica colloid were attached to a surface thereof and a connection charge amount to iron was outside the range of the present invention.

And the contact charge quantity of the fluorescent substance and the characteristic of the fluorescent lamp were evaluated by the method similar to the case of Example 17. The results are shown in Table-7.

TABLE 7

As apparent from Table 7, the metal oxide fine particles are attached to the surface of the phosphor particles, and the charging tendency of the phosphor is controlled so that the contact charging amount with the reduced iron powder having a particle size of 44 µm to 74 µm is charged in the range of -0.5 µC / g. It can be seen that blackening of the high load lamp and lowering of the luminous flux can be suppressed.

Moreover, in the said Example and the comparative example, the example of the europium loading yttrium oxide which positively charges iron parts as a fluorescent substance, and the manganese activating zinc silicate which charges negatively with iron powder was mentioned, and iron powder as surface metal oxide was mentioned. Examples of silicon oxide (silica) that charges negatively with respect to magnesium oxide and iron that are positively charged. It will be appreciated from these examples that the charging tendency of each phosphor is changed in the direction of the surface-attached metal oxide, that is, the charging tendency of the phosphor can be controlled according to the type and amount of the surface-attached metal oxide.

Example 23

First, (La, Ce, Tb), (P, Si) O ₄ and Zn ₂ SiO ₄ : Mn are selected as rare earth phosphors, and MgO ZnO is used as the metal oxide to be charged positively, and SiO _{2 is used} as the metal oxide to be charged. Were respectively selected, the suspension of the metal oxide was added to the suspension of the phosphor, stirred with suction, dried at a temperature of 125 ° C. or higher, and then calcined at 350 ° C. to pass 200 meshes. Fig. 10 and Fig. 11 show the results of measuring the charge amount of the phosphor particles thus obtained using the above-mentioned blowoff charge measuring device as a carrier with reduced iron powder. 10 shows a case of (La, Ce, Tb) (P, Si) ₄ , and FIG. 11 shows a case of Zn ₂ SiO ₄ : Mn. As can be seen from each figure, the tendency of the charging of the phosphor can be suppressed in a considerable range by the surface adhesion of the metal oxide.

The rubber phosphor-type fluorescent lamps were prepared by using the above-mentioned phosphors, and the lamps were turned on for one hour and then turned off for one day, and then the results of measuring the luminous flux of the lamps are shown in FIGS. 12 and 13, respectively. do.

12 shows a case of (La, Ce, Tb) (P, Si) O ₄ , and FIG. 13 shows a case of Zn ₂ SiO ₄ : Mn.

Moreover, as a result of measuring the relationship between the luminous flux ratio and the charging tendency after 5 minutes of lighting with respect to the fluorescent lamp, it was as shown in Figs. 14 and 15, respectively. 14 shows a case of (La, Ce, Tb) (P, Si) O ₄ , and FIG. 15 shows a case of Zn ₂ SiO ₄ : Mn.

As can be seen from the drawings, the best conditions for the luminous flux increase exist in the charging tendency of the phosphor particles to be used, and in this example, the best condition was that the charging tendency against the reduced iron was 0 to 1 µC / g.

In addition, as a result of evaluating the relationship between the luminous flux ratio and the lighting time after 300 hours of lighting for a fluorescent lamp composed of the same method except that Y ₂ O ₃ : Eu was used as the rare earth phosphor, as shown in FIG. A trend was shown. That is, the luminous flux rises to the first point A, then drops to the point B once, and then rises to the stable point C. The reduction rate from point A to point B depends on the charging tendency of the phosphor. FIG. 17 is a characteristic diagram showing the relationship between the charging tendency of the phosphor Y ₂ O ₃ : Eu with reduced iron powder and the luminous flux attenuation rate, and the luminous flux attenuation rate is (AB) ÷ A × 100% of the characteristic curve shown in FIG. Is displayed.

Here, A and B represent the light beam ratios at points A and B in FIG.

Example 24

Tube wall having the structure shown in FIG. 9 using phosphor particles having a charge characteristic of which green coating of the phosphor (La, Ce, Tb) (P, Si) O ₄ particles was coated with 0.1% by weight of MgO to impart a charge characteristic. A fluorescent lamp with a load of 750 W / m 2 was produced. As a result of performing a lighting test with this fluorescent lamp, the function which greatly improved compared with the conventional fluorescent lamp, such as a luminous flux rising characteristic, was meticulous.

In the above description, the red light emitting phosphor Y ₂ O ₃ : Eu green light emitting phosphor (La, Ce, Tb) (P, Si) O ₄ , the blue light emitting phosphor BaMgO ₂ Al ₁₁ O ₂₇ : Eu or two or more kinds The same result was obtained also when it comprised using the mixing system. 18 is a characteristic diagram showing the luminous flux decay rate and the charging tendency of charging in the case of using a ternary mixed phosphor.

As described above, the low-pressure mercury vapor discharge lamp of the present invention can suppress the occurrence of blackening during operation with excellent reproducibility, and the reduction rate of the luminous flux during long-time lighting can also be reduced. Such lamps are compact and suitable for high load specifications and their industrial value is extremely large.

Claims (3)

Low pressure mercury comprising a transparent glass tube filled with a sealing gas containing mercury and a rare gas, a fluorescent layer containing phosphor particles formed on the inner wall surface of the transparent glass tube, and means for maintaining a positive electric discharge in the sealing gas. In the vapor discharge lamp, the phosphor particles forming the phosphor layer have a charging tendency on the negative side of the metal oxide having an electronegativity of metal ions of 7.0, and a positive side of the metal oxide having a negative ion of metal ions of 11.8. Low pressure mercury vapor discharge lamp, characterized in that. Low pressure mercury comprising a transparent glass tube filled with a sealing gas containing mercury and a rare gas, a fluorescent layer containing phosphor particles formed on the inner wall surface of the transparent glass tube, and means for maintaining a positive electric discharge in the sealing gas. In the vapor discharge lamp, the phosphor particles forming the phosphor layer are charged with a low-pressure mercury vapor discharge of 3.0 μC or less per gram upon contact with soda-lime glass bis with a particle diameter of 200 μm to 500 μm. lamp. Low pressure mercury comprising a transparent glass tube filled with a sealing gas containing mercury and a rare gas, a fluorescent layer containing phosphor particles formed on the inner wall surface of the transparent glass tube, and a means for maintaining positive light discharge in the sealing gas. In the vapor discharge lamp, the phosphor particles forming the phosphor layer are charged with a positive charge of more than -0.5 μC per gram upon contact with reduced iron powder having a particle size of 44 μm to 74 μm. Discharge lamp.