JPH0228283A - Fluorescent material for white-luminescent rare gas discharge lamp and the same lamp - Google Patents

Abstract

PURPOSE:To provide a fluorescent material composed of a specific dysprosium- doped yttrium phosphovanadate fluorescent material and giving a white- luminescent rare gas discharge lamp having stable luminance and little color shift. CONSTITUTION:The subject fluorescent material is expressed by formula I or formula II (0.001<=x<=0.03; 0.4<=y<=0.7; 0.001<a<=0.01). The fluorescent material can be produced by putting the pulverized mixture of raw materials consisting of oxides, etc., of Y, Dy, P and V into a vessel made of alumina, etc., and calcining in air at 1100-1250 deg.C for 1-5hr. Preferably, the inner wall of the glass tube of the objective lamp is coated with 0.1-6wt.% of a substance exhibiting positive contact potential relative to titanium oxide together with 99.9-94wt.% of the fluorescent material.

Description

[Detailed description of the invention] [Object of the invention] (Industrial application field) The present invention provides a phosphor applied to a rare gas discharge lamp that emits white light, and a phosphor that emits white light using this phosphor. Relating to rare gas discharge lamps.

(Prior technology) Rare gas discharge lamps are made by coating the inner wall of a glass tube with phosphor.
It has a structure in which two electrodes are attached to a glass tube and a rare gas is sealed inside the glass tube. The principle of this rare gas discharge lamp is to generate a glow discharge within a glass tube, and to obtain visible light by exciting the phosphor by the rare gas resonance radiation generated by this discharge. Such rare gas discharge lamps have the advantage of not containing mercury, which is harmful to the human body, and having low temperature dependence.

Conventionally, in order to obtain white light with a rare gas discharge lamp, a calcium halophosphate phosphor alone, a divalent europium-activated aluminate phosphor, a terbium-activated lanthanum cerium phosphate phosphor, and a trivalent europium phosphor have been used. A mixture of active yttrium oxide phosphors (three-wavelength mixed phosphor) was used.

However, a rare gas discharge lamp using only a calcium halophosphate phosphor has a problem in that the phosphor deteriorates and becomes colored due to short wavelength ultraviolet rays caused by the rare gas discharge, resulting in a significant reduction in brightness. In addition, in a rare gas discharge lamp using a three-wavelength mixed phosphor, the three types of fluorescent bran are similarly degraded by the short wavelength ultraviolet rays caused by the rare gas discharge, and the degree of deterioration of each phosphor is different, so the color There is a problem that shifts occur.

Therefore, although the rare gas discharge lamp has the above-mentioned advantages, it has not been put into practical use as a white light source due to the problems caused by the deterioration of the phosphor.

(Communication to be Solved by the Invention) An object of the present invention is to provide a phosphor suitable for obtaining white light in a rare gas discharge lamp.

Another object of the present invention is to provide a white-emitting rare gas discharge lamp that uses this phosphor and exhibits less reduction in brightness and less color shift.

(Means for Solving the Problems) As a result of various studies on phosphors suitable for obtaining white light emission in rare gas discharge lamps, the present inventors found that dysprosium-activated yttrium phosphovanadate phosphors are promising. I found out. Note that the dysprosium-activated yttrium phosphovanadate phosphor is known as a yellow phosphor for high-pressure mercury lamps (for example, Japanese Patent Publication No. 4G-43035, u, s, p).

3.661,791). However, the composition of the dysprosium-activated yttrium phosphovanadate phosphor according to the present invention is different from that of known phosphors.

The white-emitting rare gas discharge lamp phosphor of the present invention has the general formula N] Y'+-Dy, Vl-PF 04
[Iko (however, o, oot≦X≦0.03.0.4≦
y≦0.7).

The second white-emitting rare gas discharge lamp phosphor of the present invention is
General formula [nl Yl-x DV* Vl-y P y Oa;
a K [il] (0.001≦X≦0.
03.0.4≦y≦0. a, 0.001 < a≦0.
01).

The phosphor of the present invention emits white light by itself, has significantly improved brightness, and has little color shift. Furthermore, the general formula [II
] The luminance of the phosphor represented by K is further improved by adding K.

In the present invention, the range of X indicating the content of Dy, which is a constituent element of the phosphor represented by the general formula [I] or [II], is set to o, ooi to 0,03 for the following reasons. . That is, if X is less than 0.001, the mixing of Dy becomes non-uniform and the luminous efficiency decreases.

On the other hand, when X exceeds 0.03, the emitted light color becomes yellowish and white light cannot be obtained. The more preferable range of X is 0.00
It is 3 to 0.02.

In the present invention, the range of y indicating the content of P, which is a constituent element of the phosphor represented by the general formula [I] or [nl, is set to 0.
．． The reason for setting it to 4 to 0.7 is as follows. That is, if y is less than 0.4, the emitted light color will be yellowish and white light will not be obtained. On the other hand, when y exceeds 0.7, the luminous efficiency decreases. A more preferable range of y is 0.5 to 0.6.

In the present invention, K, which is a constituent element of the phosphor represented by the general formula [II], has the effect of accelerating the sintering reaction, increasing the luminescence intensity, and preventing deterioration over time. The range of a indicating the K content is 0.0f11<a≦0. The reason for selecting O1 is as follows. That is, a is 0.
If it is less than 001, the sintering reaction will be insufficient and the luminescence intensity will decrease. On the other hand, a is 0. When it exceeds O1, the phosphor takes on a yellow-green color and the luminescence intensity decreases. The effect of adding K is
It becomes particularly large when and y are within the above ranges.

A method for manufacturing a phosphor according to the present invention will be explained. First, Y.S.
After weighing a predetermined amount of each of the oxides, oxalates, ammonium salts, carbonates, and other compounds that will become Dy, PSV (and K)+7)7-s, they are thoroughly ground and mixed using, for example, a ball mill. In addition, in the present invention, as the flux, for example, Japanese Patent Publication No. 4B-43035, U, S,
Na2COi used in P, 3,881,791
It is preferable to use YB03 or the like as the flux, since the use of YB03 causes a decrease in the brightness of the phosphor. Next, the obtained mixture is placed in a container made of alumina or silicon carbide, and is heated to
Bake for ~5 hours. The container made of alumina or silicon carbide is preferably porous. This is to ensure that the gas generated by heating the mixture can be easily removed from the system. By expelling the gas generated in this way out of the system, a phosphor with good characteristics can be obtained. The obtained fired product is cooled, sieved, washed, filtered,
By drying, the phosphor according to the present invention can be prepared.

The white light emitting rare gas discharge lamp of the present invention includes a glass tube, a phosphor represented by the general formula [I] or [■] coated on the inner wall of the glass tube, and two electrodes attached to the glass tube. However, a rare gas is sealed inside the glass tube.

Since the white light emitting rare gas discharge lamp of the present invention uses the above-mentioned phosphor, the total luminous flux is improved and the color shift is small.

The white light-emitting rare gas discharge lamp of the present invention can be produced by following conventional methods.
A binder is dissolved in a solvent, and the general formula [I] or [
■ Prepare a coating solution by suspending the phosphor represented by
After applying this coating solution to the inner wall of the glass tube and drying it, attaching the two electrodes to the glass tube, it is easy to do so by filling the glass tube with at least one rare gas among xenon, krypton, argon, and neon. It can be made.

Note that it is desirable to coat the inner wall of the glass tube with a phosphor represented by the general formula [I] or [II] together with a substance that exhibits a more positive contact charge than untreated titanium oxide. An example of a substance exhibiting a more positive contact charge than unsurface-treated titanium oxide is IFfi, which is at least one of alumina and magnesia. If a substance exhibiting a more positive contact charge than titanium oxide is mixed with the phosphor and applied to the inner wall of the glass tube in this way, the effect of preventing deterioration of the phosphor can be obtained. These are phosphors 99.9~
94% by weight, 0 substances showing more positive contact charge than titanium oxide
．． It is desirable to mix in a proportion of 1 to 6% by weight. If the amount of the substance exhibiting a more positive contact charge than titanium oxide is less than 0.1% by weight, the effect of preventing the phosphor from deteriorating over time will not be sufficient, and if it exceeds 6% by weight, the brightness will decrease significantly. Also,
Substances that exhibit a more positive contact charge than phosphors and titanium oxide are
After being mixed, it is usually fired in the air at 7 (10 to 900°C) for 1 to 2 hours. When using magnesia, even if you omit the firing after mixing, the effect is the same as that of firing. can get.

(Example) The present invention will be explained in detail below.

FIG. 1 shows a rare gas discharge lamp of a counter-electrode type manufactured in the following examples. In Figure 1, diameter 5
．． 8. The inner wall of a glass tube l with a length of 254 mm is coated with the phosphor 2 according to the present invention, electrodes 3.3 are attached to opposite ends of the glass tube 1, and inside the glass tube 1 there are Enclosed with rare gas.

A high frequency inverter 4 and an electric i11 are connected between the opposing electrodes 3 and 3.
! 5 is connected.

FIG. 2 shows an external electrode type rare gas discharge lamp manufactured in the following example. In Figure 2, diameter 2
．． 411111, the inner wall of a glass tube 1 having a length of 88 ss is coated with the phosphor 2 according to the present invention, an electrode 3 is provided at one end of the glass tube 1, and an external electrode 6 is provided on a part of the outer wall of the glass tube 1.
are attached to each glass tube 1, and rare gas is sealed inside the glass tube 1. A high frequency inverter 4 and a power source 5 are connected between the electrode 3 and the external electrode 6.

In any type of rare gas discharge lamp, a phosphor is excited to emit light by a rare gas resonance line generated as a result of glow discharge of a rare gas sealed in a glass tube.

Examples 1 to 16, Comparative Example 1 and Conventional Example First, phosphors having the compositions shown in Table 1 were prepared. That is, Y203,
Dy203, V205 and ammonium hydrogen phosphate powders were weighed, ground and mixed using a ball mill for 2 hours. Next, the obtained mixed powder was placed in a porous silicon carbide crucible and fired at 1100° C. for 3 hours in the atmosphere. Subsequently, the obtained fired product was cooled, sieved, washed, and dried to prepare a phosphor. Table 1 shows the results of measuring the chromaticity of these phosphors.

Next, cellulose nitrate was dissolved as a binder in butyl acetate, and each phosphor was suspended in this to prepare a coating liquid. These coating solutions were applied to the inner wall of the glass tube and dried, two electrodes were attached to the glass tube, and a rare gas of 100% xenon was applied to the inside of the glass tube at a gas pressure of 110 Torr.
A rare gas discharge lamp of the opposed electrode type shown in FIG. 1 or an external electrode type rare gas discharge lamp shown in FIG. Table 1 shows the results of API determination of the chromaticity of these rare gas discharge tubes.

In Table 1, the conventional rare gas discharge lamp uses a mixture of a divalent europium-activated aluminate phosphor, a terbium-activated lanthanum cerium phosphate phosphor, and a trivalent europium-activated yttrium oxide phosphor. (three-wavelength mixed phosphor).

A chromaticity diagram is shown in FIG. 3 based on the data of the opposed electrode type rare gas discharge lamp shown in Table 1. In this figure 3,
The center of the white gamut specified by JIS Z81LO as a desirable white gamut, that is, (x, y) - (0, 31!)
0.40), ((1, 27, 111, 29) are the two vertices of the rectangle surrounded by a chain line.

In addition, using the same phosphor as in Example 7 in Table 1, a rare gas mixture of xenon, neon, argon, or krypton was sealed in a glass tube as shown in Table 2, and as shown in FIG. A rare gas discharge lamp with a counter electrode type was fabricated. Table 2 shows the i'DJ chromaticity results for these rare gas discharge lamps.

From FIG. 3, Tables 1 and 2, it can be seen that the emission colors of the rare gas discharge lamps of Examples 1 to 16 are in the so-called white range. However, as can be seen from FIG. 3, the y value representing the P content is 0.4, and the X value representing the Dy content is 0.4.
Rare gas discharge lamps using 01 and 0.03 phosphors (
In Example 3.4), although the luminous efficiency is good, the chromaticity deviates from the desired white range. Therefore, it is desirable to use a phosphor with a y value of 0.5 or more.

Next, Fig. 4 shows the results of Ul determination of the change in chromaticity over time after lighting for the rare gas discharge lamp of Example 7 and the conventional rare gas discharge lamp (both external electrode types). The results of measuring changes over time are shown in FIG.

As is clear from FIGS. 4 and 5, the rare gas discharge lamp of Example 7 has a smaller change in chromaticity over time than the conventional rare gas discharge lamp, and also has a significantly improved brightness maintenance rate. You can see that

Examples 17 to 24 First, phosphors having the compositions shown in Table 3 were prepared. That is, Y2O3, D
Powders of y202, V2O9, diammonium hydrogen phosphate, and potassium carbonate were weighed, ground and mixed using a ball mill for 2 hours. Next, the obtained mixed powder was placed in a porous silicon carbide crucible and fired in the atmosphere at 1200°C for 3 hours (Examples 17 to 22.24) and at 1150°C for 3 hours (Example 23). did. Subsequently, the obtained fired product was cooled, sieved, washed, and dried to prepare a phosphor.

The results of determining the chromaticity and relative brightness for each of these samples are also listed in Table 3. This relative brightness is calculated by irradiating each phosphor with ultraviolet rays with a wavelength of 254n+n and increasing the brightness by Apl.
It is a relative value expressed with the brightness of the sample of Example 7 set as 100. As far as these dysprosium-activated yttrium phosphovanadate phosphors are concerned, there is almost no difference in the relative value of the luminance whether the wavelength of the irradiated ultraviolet light is 254 nn+ or 147 r+m.

As is clear from Table 3, the emission colors of the phosphors of Examples 17 to 24 are in the white range. In addition, in the phosphors of Examples 17 to 24, the brightness was significantly improved by adding K. For example, when comparing Example 22 and Example 7, which have the same luminous chromaticity, Example 22 has a brightness of about 5%.
It has improved by 0%.

Next, cellulose nitrate was dissolved as a binder in butyl acetate, and each phosphor was suspended in this to prepare a coating liquid. These coating solutions were applied to the inner wall of the glass tube and dried, two electrodes were attached to the glass tube, and a rare gas of 100% xenon was sealed inside the glass tube at a gas pressure of 90 Torr, as shown in Figure 1. A rare gas discharge lamp of the opposite electrode type as shown was fabricated. Table 3 shows the results of measuring the total luminous flux and chromaticity of these rare gas discharge lamps.

From Table 3, it can be seen that the emission colors of the rare gas discharge lamps of Examples 17 to 24 are also in the so-called white range.

Next, regarding the rare gas discharge lamp of Example 22 and the conventional rare gas discharge lamp (both are counter electrode types),
Figure 6 shows the results of measuring changes in chromaticity over time after lighting.

As is clear from FIG. 6, it can be seen that the rare gas discharge lamp of Example 22 shows a smaller change in chromaticity over time than the conventional rare gas discharge lamp.

Examples 25 to 30 and Comparative Examples 2 to 4 A phosphor having the same composition as Example 7 or Example 22, and alumina or magnesia were blended in the proportions shown in Tables 4 and 5, and mixed using a ball mill. After that, in the atmosphere, 80
It was baked at 0°C for 1 hour. Next, a coating solution was prepared by dissolving cellulose nitrate as a binder in butyl acetate, and suspending the mixture of the above-mentioned phosphor and alumina or magnesia therein. These coating solutions were applied to the inner wall of the glass tube and dried, two electrodes were attached to the glass tube, and a rare gas of 50% xenon and 50% neon was sealed inside the glass tube so that the gas pressure was 90 TOrr. An external electrode type rare gas discharge lamp shown in FIG. 2 was manufactured. Tables 4 and 5 show the results of measuring the brightness (initial value) at the center of these rare gas discharge lamps.

Next, Fig. 7 shows the results of determining the change in relative brightness over time after lighting for the rare gas discharge lamp of Example 7.26.28, and the relative brightness for the rare gas discharge lamp of Example 22.29.30. The results of measuring changes over time are shown in FIG. 8.

As can be seen from Table 4, the initial value of the relative brightness is that for all of the rare gas discharge lamps of Examples 25 to 28 and Comparative Example 2.3 in which alumina or magnesia is used, magnesia is used as compared to alumina or magnesia. It is smaller than the noble gas discharge lamp of Example 7 which was not used.

On the other hand, as can be seen from FIG. 7, the relative brightness of the rare gas discharge lamps of Examples 2G and 28 becomes greater than that of the rare gas discharge lamp of Example 7 after approximately 200 hours have elapsed after lighting. However, in the rare gas discharge lamp of Comparative Example 2.3 in which the amount of alumina or magnesia was too large, the initial value of the relative brightness was too small, so the reversal of the relative brightness as described above was not observed.

Furthermore, from Table 5 and FIG. 8, there is a similar relationship as described above between the rare gas discharge lamp of Example 22 and the rare gas discharge lamps of Example 29.3o and Comparative Example 4. I'm so excited.

E. Effects of the Invention As detailed above, even when the phosphor of the present invention is used alone, white light can be obtained, and the luminance is significantly improved. Also,
The rare gas discharge lamp of the present invention using such a phosphor has an improved total luminous flux and a small brown shift. Therefore, the industrial value of the present invention is extremely large.

[Brief explanation of the drawing]

Figure 1 is a cross-sectional view of a rare gas discharge lamp of the opposed electrode type.
Figure 2 is a cross-sectional view of an external electrode type rare gas discharge lamp.
Fig. 3 is a chromaticity diagram of the opposed electrode type rare gas discharge lamps of Examples 1 to 12, and Fig. 4 shows the chromaticity changes over time of Example 7 and the conventional external electrode type rare gas discharge lamps. Fig. 5 is a characteristic diagram showing the change over time in the brightness maintenance factor of Example 7 and a conventional external electrode type rare gas discharge lamp (gas pressure: 110 Torr), and Fig. 6 is a characteristic diagram of Example 7 and Example 7. 22 and a chromaticity diagram showing the change in chromaticity over time of a conventional opposed electrode type rare gas discharge lamp, FIG. 7 is Example 7.26
．． 28 external electrode type rare gas discharge lamp (gas pressure:
90 Torr) is a characteristic diagram showing changes in relative brightness over time;
FIG. 8 is a characteristic diagram showing the change over time in the relative brightness of the external electrode type rare gas discharge lamp (gas pressure: 90 Torr) of Examples 22, 29, and 30. 1...Glass tube, 2...phosphor, 3...electrode, 4...
...local frequency inverter, 5...power supply, 6...external electrode.

Claims (6)

[Claims] (1) General formula [I] Y_1_-_xDy_xV_1_-yP_yO_4[
I] (0.001≦x≦0.03, 0.4≦y
≦0.7) A white-emitting phosphor for a rare gas discharge lamp. (2) General formula [II] Y_1_-_xDy_xV_1_-_yP_yO_4;
aK[II] (0.001≦x≦0.03, 0.
4≦y≦0.7, 0.001<a≦0.01) A white-emitting phosphor for a rare gas discharge lamp. (3) A device comprising a glass tube, the phosphor according to claim (1) or (2) coated on the inner wall of the glass tube, and two electrodes attached to the glass tube, and a rare gas inside the glass tube. A white-emitting rare gas discharge lamp characterized by being enclosed. (4) The glass tube according to claim (3), characterized in that the inner wall of the glass tube is coated with a mixture of the phosphor according to claim (1) or (2) and a substance exhibiting a more positive contact charge than titanium oxide. White-emitting rare gas discharge lamp. (5) The white light-emitting rare gas discharge lamp according to claim (4), wherein the substance exhibiting a more positive contact charge than titanium oxide is at least one of alumina and magnesia. (6) Phosphor 99.9 according to claim (1) or (2)
5. The white-light-emitting rare gas discharge lamp according to claim 4, characterized in that the white light-emitting rare gas discharge lamp comprises a mixture of .about.94% by weight and 0.1-6% by weight of a substance exhibiting a more positive contact charge than titanium oxide.