JPH0517954B2 - - Google Patents

Description

[Detailed description of the invention]

INDUSTRIAL APPLICATION FIELD The present invention relates to a fluorescent lamp, specifically, a fluorescent lamp with a color temperature of emitted light.
This invention relates to a high color rendering type fluorescent lamp which has a value of 4200k to 5600k, has an EDL type color rendering class defined in JISZ9301 for the color rendering index, and satisfies each numerical value of the light source color class white. Structure of conventional examples and their problems The phosphor conventionally used in fluorescent lamps for general lighting is antimony/manganese-activated halocalcium phosphate phosphor, but this lamp has low color rendering properties. However, its use in places where high color rendition is required, such as museums and color printing factories, is restricted. As a fluorescent lamp with high color rendering properties,
For example, a so-called two-layer coating method involves mixing several types of phosphors to approximate the spectral distribution of a reference light source, while simultaneously suppressing mercury volatiles in the short wavelength region of the visible region, which inhibit the increase in color rendering. EDL-type fluorescent lamps are known (Japanese Patent Publication No. 41-9868, Japanese Patent Publication No. 15895-1973). However, with these conventional methods, the lamp manufacturing process is complicated, production efficiency is reduced, and variations in color rendering properties and reduction in lamp efficiency are unavoidable, which has been a long-standing problem. In recent years, fluorescent lamps that have improved the above-mentioned problems have been proposed in Japanese Patent Laid-Open Nos. 54-102073 and 1987-115489, and have made some progress. However, the former (Japanese Unexamined Patent Publication No. 102073/1983) mainly consists of a divalent europium-activated strontium borophosphate phosphor and a tin-activated strontium/magnesium orthophosphate phosphor, and has an average color rendering index R _a 99
In order to increase the chromaticity of the lamp and set it on the blackbody locus, a small amount of calcium halophosphate phosphor and zinc silicate phosphor are further added to provide a fluorescent lamp. However, zinc silicate phosphors suffer from relatively large deterioration when applied to fluorescent lamps, and therefore have the disadvantage that the special color rendering index decreases due to a decrease in the green component during the life of the lamp. On the other hand, the latter (Japanese Unexamined Patent Publication No. 115489/1989) mixes three types of phosphors, including blue and red phosphors that emit light in a narrow band, so color management such as light color and color rendering properties is controlled. It had the disadvantage that it was difficult to In addition, as shown in Japanese Patent Application Laid-Open No. 58-40763, a divalent europium-activated alkaline earth metal halophosphate phosphor is arranged as a blue-green phosphor,
EDL type phosphor lamps are known in which the lamp efficiency is improved by a single layer coating mixed with a tin-activated strontium/magnesium orthophosphate phosphor. However, in this case, the phosphor is a mixture of only two types, so it is simple, but on the other hand, it is made of an alkaline earth metal activated with divalent europium, whose emission spectrum tends to change due to slight changes in the phosphor composition. Since a halophosphate phosphor is used, if the emission color of this phosphor changes slightly, it becomes impossible to maintain the chromaticity of the lamp on the black body locus at a color temperature of, for example, 5000K.
2 above when color matching in the lamp manufacturing process
This method has the disadvantage that the emission spectrum of each type of phosphor must 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 life. The present invention provides a fluorescent lamp that exhibits Structure of the Invention The fluorescent lamp of the present invention has the general formula 4 (Sr _1-x Eu _x )
Activated with divalent europium, represented by O・yAl ₂ O ₃・zY ₂ O ₃ , 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 a tin-activated strontium-magnesium orthophosphate and a tin-activated strontium-barium-magnesium orthophosphate phosphor; and an antimony-manganese activated alkali phosphor. A third phosphor that is at least one of an earth metal halophosphate phosphor and an antimony-activated alkaline earth metal halophosphate phosphor is mixed, and the mixed phosphor is placed in a glass tube. It is characterized by being attached to the wall, improves lamp efficiency, facilitates color matching during the lamp manufacturing process, and consistently exhibits high color rendering throughout the lamp's life. Description of Examples In a fluorescent lamp, the average color rendering index R _a is 96.
In order to obtain the above-mentioned high color rendering properties, it is not sufficient to adjust the spectral distribution by using a mixture of phosphors.
It is known that it is necessary to suppress the emission energy of 405 nm and 436 nm, which are mercury emission lines in the short wavelength region of the visible region. 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 halophosphate have been used as materials to suppress the mercury bright line. EDL-type fluorescent lamps have been proposed that improve lamp efficiency by using blue-green phosphors such as calcium-magnesium phosphors and divalent europium-activated strontium-magnesium aluminate phosphors. There is.
These blue-green phosphors have a wide emission half-width (the width of the emission spectrum measured at 50% of the maximum emission intensity) of 80 nm to 120 nm, so they are different from existing orange phosphors (e.g. There is little scope for selecting and using a high-efficiency phosphor that does not reduce the color rendering properties even if it is further added when mixed with a tin-activated strontium/magnesium orthophosphate phosphor. The inventors selected a divalent europium-activated strontium-yttrium aluminate phosphor with improved emission peak height by dissolving yttrium oxide as a material for suppressing the mercury emission line. , a fluorescent lamp constructed as described in the claims is a conventional EDL.
It has been discovered that the lamp efficiency is greatly improved compared to fluorescent lamps, and it also achieves stable and high color rendering properties. Furthermore, the amount of expensive rare earth phosphor used in the fluorescent lamp according to the present invention is on the order of 10 to 20% by weight, compared to the conventional EDL type fluorescent lamp which improves lamp efficiency by a single layer coating. It also has the advantage of greatly reducing the amount used (for example, JP-A-54-102073, JP-A-58-40763), which is 40 to 60% by weight. There is. The divalent europium-activated strontium yttrium aluminate phosphor used in the fluorescent lamp of the present invention has the general formula 4 (Sr _1-x Eu _x )O.
It is a phosphor represented by yAl ₂ O ₃ zY ₂ O ₃ , where x, y and z are respectively defined as 0.005≦x≦0.2 6≦y≦8 0<z≦0.1, and the inventor Some of these were proposed in earlier patent applications, and the height of the emission peak was improved by dissolving yttrium oxide in a conventional divalent europium-activated strontium aluminate phosphor. be. Here, x of the europium content was selected so that 0.005≦x≦0.2. The reason for this is that if x is less than 0.005, the light emission output will be insufficient and the absorption of light in the short wavelength region of the visible region will be small, making it unsuitable for the fluorescent lamp of the present invention. In addition, when x exceeds 0.2, the decrease in luminous output is not so large, but
This is because the price of phosphors has skyrocketed and it is not practical. y
The value of is limited to 6≦y≦8. The reason is,
This is because, outside this range, other strontium aluminates such as SrAl ₁₂ O ₁₉ are generated, reducing the light emission output. The effect obtained by adding yttrium oxide is shown in FIG. As is clear from Figure 1, the amount z of yttrium oxide is O<z
An improvement in the emission peak height can be obtained in the range of ≦0.1. The divalent europium-activated strontium-yttrium aluminate phosphor described above is manufactured as follows. That is, after firing, each oxide, phosphate, and
A predetermined amount of each compound such as carbonate, ammonium salt, or halide is weighed out, an appropriate amount of a boron-containing compound such as boric acid, ammonium tetraborate, or strontium borate is added to form a raw material mixture, and the mixture is thoroughly ground and mixed. The resulting mixture was placed in a mildly reducing atmosphere.
The first phosphor used in the present invention is obtained by firing at a temperature of 1100° C. to 1600° C. for several hours. Table 1 shows the luminescent properties of typical phosphors suitably used in the present invention.

[Table] Figure 2 shows the emission spectra of these phosphors upon excitation with ultraviolet light. The symbols in the figure correspond to those in Table 1. Examples of the present invention will be described below. A 40 watt straight tube type fluorescent lamp was prepared by mixing phosphors of each color and applying the phosphor mixture to the inner wall of a glass tube having a tube diameter of 32 mm according to a conventional manufacturing method. Table 2 shows the types of phosphors (indicated by the symbols in Table 1) and their mixing ratios, as well as the obtained lamp characteristics along with comparative examples and known examples.

[Table] As is clear from Table 2, the total luminous flux of the fluorescent lamps shown in Examples 1 to 3 is greatly improved compared to the comparative examples and known examples. This is a divalent europium-activated strontium yttrium aluminate, 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 a phosphor. Furthermore, a two-dimensional effect has been obtained in that the amount of expensive rare earth phosphor used can be reduced. The spectral distribution of the fluorescent lamp obtained in Example 2 is shown in FIG. Effects of the Invention As explained above, the fluorescent lamp of the present invention has a high emission peak height by dissolving yttrium oxide in place of the conventional divalent europium-activated strontium aluminate phosphor. Improved divalent europium-activated strontium
It uses a yttrium aluminate phosphor and is constructed as described in the claims,
Compared to conventional EDL type fluorescent lamps, it achieves high color rendering with no color contrast, improves lamp efficiency, consistently exhibits high color rendering throughout its life, and facilitates color matching during the lamp manufacturing process. This makes it possible to provide a fluorescent lamp with the following advantages.

[Brief explanation of the drawing]

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

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≦0.2, 6≦y≦8, 0<z≦0.1, respectively.
a second phosphor which is at least one of a tin-activated strontium-magnesium orthophosphate phosphor and a tin-activated strontium-barium-magnesium orthophosphate phosphor; and an antimony-manganese phosphor. a third phosphor that is at least one of an activated alkaline earth metal halophosphate phosphor and an antimony activated alkaline earth metal halophosphate phosphor; A fluorescent lamp characterized in that the inner wall of the glass tube is coated with