JPH0517955B2 - - Google Patents

Description

[Detailed description of the invention]

Industrial Application Field The present invention relates to a fluorescent lamp, in particular, the color temperature of the emitted light is
It has a value of 4200K to 5600K, and the color rendering classification specified in JISZ9301 for color rendering index is EDL type,
The present invention relates to a high color rendering type fluorescent lamp whose light source color category satisfies each numerical value of white. Conventional structure and problems The phosphor conventionally used in general lighting fluorescent lamps is antimony/manganese-activated calcium halophosphate phosphor, but this fluorescent lamp has a low color rendering property, so it is not suitable for art museums. It is unsuitable for use in places where high color rendition is required, such as color printing factories. For fluorescent lamps with high color rendering properties, for example, several types of phosphors may be mixed to approximate the spectral distribution of a reference light source, while suppressing mercury emission lines in the visible short wavelength range that inhibit the increase in color rendering properties. EDL using so-called two-layer coating
Type fluorescent lamps are known (Japanese Patent Publication No. 41-9868, Japanese Patent Publication No. 15895-1987). However, these conventional lamp manufacturing processes are complicated and production efficiency is reduced, and variations in color rendering and lamp efficiency are unavoidable, which have been problems for many years. In recent years, a fluorescent lamp that has improved the above-mentioned problems has been proposed in Japanese Patent Application Laid-Open No. 102073/1983, and has made some progress. However, the emission peak wavelength of the blue-green phosphor used in this case is too short, so in order to set the chromaticity of the lamp on the blackbody locus, it is necessary to use a fluorescent lamp such as a zinc silicate phosphor.
A phosphor that is relatively unstable throughout its life must be used;
It had the disadvantage that special color rendering indexes such as R ₉ and R ₁₁ decreased. Also, JP-A-58-40763
As shown in the publication, a divalent europium-activated alkaline earth metal halophosphate phosphor is arranged as a blue-green phosphor, mixed with a tin-activated strontium/magnesium orthophosphate phosphor and coated in a single layer. Fluorescent lamps with improved lamp efficiency and color rendering properties are known. However, in this case, the phosphor is a mixture of only two types, so it is simple, but on the other hand, it is a divalent europium-activated alkaline earth metal halophosphate whose emission spectrum tends to change due to small changes in the phosphor composition. Since a phosphor is used, if the emission color of this phosphor changes slightly, the chromaticity of the lamp cannot be maintained on the black body locus at a color temperature of, for example, 5000K. This method had the disadvantage that the emission spectra of the two types of phosphors had to be strictly defined. Purpose of the Invention The present invention provides an EDL type fluorescent lamp that eliminates the above-mentioned drawbacks, improves lamp efficiency, facilitates color matching in the lamp manufacturing process, and provides stable high color rendering throughout the lamp's life. The purpose of this invention is to provide a fluorescent lamp that exhibits unique characteristics. Structure of the Invention The fluorescent lamp of the present invention has the general formula 4 (Sr _1-x Eu _x )
It is represented by O・yAl ₂ O ₃・ZY ₂ O ₃ and is inactivated with divalent europium, where x, y and Z satisfy 0.005≦x≦0.2, 6≦y≦8, 0<Z≦0.1, respectively. The first
a second phosphor which is at least one of tin-activated strontium-magnesium orthophosphate and tin-activated strontium-barium-magnesium orthophosphate; and an antimony-manganese activated alkaline earth metal halophosphorus. a third phosphor that is at least one of an acid salt and an antimony-activated alkaline earth metal halophosphate; and a third phosphor that has an emission peak in the wavelength range of 440 nm to 490 nm and is activated with divalent europium. This product is characterized by being made by mixing the phosphor of 4 and coating the mixed phosphor on the inner wall of the glass tube, which improves the lamp efficiency, facilitates color matching in the lamp manufacturing process, and lasts for a long time during the lamp life. It is designed to show stable and high color rendering properties throughout the process. Description of Examples In order to obtain a high color rendering property with an average color rendering index Ra of 96 or higher in a fluorescent lamp, it is insufficient to adjust the spectral distribution by mixing phosphors; Some 405nm, 436n
It is known that it is necessary to suppress the emission energy of m. In recent years, efforts have been made to improve the efficiency of high color rendering fluorescent lamps, and divalent europium-activated strontium borophosphate phosphors and divalent europium-activated barium-calcium-magnesium halophosphate phosphors have been used as materials to suppress the mercury emission line. Improved lamp efficiency by utilizing blue-green phosphors such as strontium-magnesium-aluminate and divalent europium-activated strontium-magnesium aluminate phosphors.
EDL type fluorescent lamps have been proposed. but,
These divalent europium-activated blue-green phosphors have a half-value width (the width of the emission spectrum measured at the emission intensity at 50% of the maximum emission intensity).
Due to its wide range of 80nm to 120nm, when mixed with existing orange phosphors (for example, tin-activated strontium/magnesium orthophosphate), it is possible to create a high-efficiency or high-brightness phosphor that does not reduce color rendering even when added. There is little room for utilizing this to increase lamp efficiency. In other words, in these conventional technologies, the lamp efficiency is largely dependent on the luminous output of the blue-green phosphor and the orange phosphor, and the addition of a phosphor that is bright enough to improve the lamp efficiency affects the color rendering of the lamp. This was impossible because it would reduce the sex. Based on these circumstances, the present inventors used a blue-green phosphor with a narrow half-width of emission as a material for suppressing the mercury emission line, contrary to the conventional method, and After conducting many experiments on combinations of phosphors that improve lamp efficiency by arranging light emitting light on the side and exhibit stable high color rendering properties, we found that divalent europium-activated strontium was used as the blue-green phosphor.・By selecting yttrium aluminate phosphor, the fluorescent lamp constructed as described in the claims can significantly improve the lamp efficiency and stably increase the lamp efficiency compared to the conventional EDL type fluorescent lamp. It was discovered that the color rendering properties can be achieved. Furthermore, since the fluorescent lamp according to the present invention uses a blue-green phosphor with a narrow half-width of light emission as described above, it is possible to use the conventional EDL using a single-layer coating.
Blue-green phosphor, an expensive rare earth phosphor used in fluorescent lamps, accounts for 40 to 60% of the total mixed phosphor.
It also has the advantage that the amount used can be significantly reduced compared to the percentage by weight. The divalent europium-activated strontium, yttrium, and the like used in the fluorescent lamp of the present invention
Aluminate phosphor has general formula 4 (Sr _1-x Eu _x )
It is a phosphor represented by O・yAl ₂ O ₃・ZY ₂ O ₃ in which x, y and Z are respectively defined as 0.005≦x≦0.2 6≦y≦8 0<Z≦0.1, and the present invention Some of them had previously proposed this in an unpublished patent application.
The emission peak height of the conventional divalent europium-activated strontium aluminate phosphor has been improved. Europium content x is 0.005≦x≦
It was selected to be 0.2. The reason is that x
If it is less than 0.005, the luminous output is insufficient, and x
If it exceeds 0.2, the drop in luminous output is not so large, but the price of the phosphor increases, making it impractical. The value of x is particularly preferably in the range 0.02≦x≦0.1. The aluminum content y is limited to 6≦y≦8. The reason is that outside this range other strontium aluminates, such as SrAl ₂ O ₄ ,
This is because SrAl ₁₂ O ₁₉ etc. are generated and the light emission output is reduced. The yttrium content Z was selected so that 0<Z≦0.1. The reason for this is that when Z is within this range, a particularly remarkable improvement in the height of the emission peak can be obtained. Figure 1 shows Sr _0.95 Al ₁₄ O ₂₅ :
The change in the luminescence peak height with respect to the yttrium content Z is shown when Z moles of Y ₂ O ₃ are dissolved in a solid solution with respect to the basic composition of Eu _0.05 . As is clear from FIG. 1, the effect of improving the luminescence peak height is seen in the range of O<Z≦0.1, and the range of 0.015≦Z≦0.08 is particularly desirable. The divalent europium-activated strontium-yttrium-aluminate phosphor described above can be manufactured as follows. That is, Sr after firing,
A predetermined amount of compounds such as oxides, carbonates, phosphates, ammonium salts, and halides that can be sources of Al, Y, and Eu are weighed and used as fluxes such as boric acid, boric anhydride, ammonium tetraborate, and boric acid. Add an appropriate amount of boron-containing compounds such as strontium to make a raw material mixture, and
The first phosphor used in the present invention is obtained by firing at a temperature of 1400° C. for several hours. Table 1 shows examples of luminescent properties of phosphors preferably used in the present invention. Figure 2 shows the emission spectra of these phosphors upon UV excitation.
The symbols in the figure correspond to those in Table 1.

[Table] Examples of the present invention will be described below. A 40 watt straight tube fluorescent lamp was prepared by mixing phosphors of each color and depositing the phosphor mixture on the inner wall of a glass tube having a tube diameter of 32 mm. Table 2 a, b
shows the types of phosphors (indicated by symbols in Table 1) and their mixing ratios, and also shows the obtained lamp characteristics together with comparative examples and known examples.

[Table] As is clear from Table 2-a and b, Example 1
It can be seen that the total luminous flux of the fluorescent lamps shown in items 3 to 3 is significantly improved compared to the comparative example and the known example. This is a divalent europium-activated strontium-yttrium-aluminate fluorescent material, which has an improved emission peak height by incorporating yttrium oxide as a solid solution, instead of the conventional divalent europium-activated strontium aluminate phosphor. This effect was obtained by using the fluorescent substance as the first phosphor. It was confirmed that the fluorescent lamp of the present invention had good life characteristics and exhibited stable high color rendering properties throughout its life. Furthermore, the phosphor mixture used in the fluorescent lamp of the present invention is basically a mixture of four types,
Another advantage is that color matching during the manufacturing process is easy. Furthermore, in the fluorescent lamp according to the present invention, as is clear from the comparison between Examples 1 to 3 and the comparative example, among the expensive rare earth phosphors, the first
A secondary effect of reducing the amount of phosphor used as indicated by symbols A ₁ and A ₂ in the table was also obtained. The spectral distribution of the fluorescent lamp obtained in Example 2 is shown in FIG. Effects of the Invention As explained above, the present invention provides a divalent europium-activated strontium aluminate phosphor that is improved in luminescence peak height by dissolving yttrium oxide in place of the conventional divalent europium-activated strontium aluminate phosphor. Europium activated strontium, yztrium,
It uses an aluminate phosphor and is constructed as described in the claims, and is different from the conventional EDL.
It is possible to provide a fluorescent lamp which has clearly improved lamp efficiency compared to a compact fluorescent lamp, exhibits stable high color rendering properties throughout its life, and has the advantages of easy color matching in the lamp manufacturing process. It is.

[Brief explanation of the drawing]

Figure 1 is a diagram showing the change in emission peak height due to the addition of yttrium in a divalent europium-activated strontium-yttrium-aluminate phosphor, and Figure 2 is a diagram showing a phosphor suitably used in the fluorescent lamp of the present invention. FIG. 3 is a diagram showing the spectral distribution of the fluorescent lamp shown in Example 2 of the present invention.

Claims (1)

[Claims] 1 General formula, 4(Sr _1-x Eu _x )O・yAl ₂ O ₃・ZY ₂ O ₃
, where x, y and Z satisfy 0.005≦x≦0.20 6≦y≦8 0<Z≦0.1, respectively.
a second phosphor which is at least one of tin-activated strontium-magnesium orthophosphate and tin-activated strontium-barium-magnesium orthophosphate; and an antimony-manganese activated alkaline earth metal halophosphorus. a third phosphor that is at least one of an acid salt and an antimony-activated alkaline earth metal halophosphate; and a third phosphor that has an emission peak in the wavelength range of 440 nm to 490 nm and is activated with divalent europium. A fluorescent lamp characterized in that the mixed phosphor is mixed with the phosphor of No. 4 and the mixed phosphor is adhered to the inner wall of a glass tube.