JPH07258632A - Fluorescent substance and fluorescent lamp in which the same is used - Google Patents

Abstract

PURPOSE:To provide a red or deep red color light-emitting fluorescent substance showing a high color-rendering property, having a high light emission efficiency, and suitable for three wavelength region emission type fluorescent lamps. CONSTITUTION:A red or deep red color light-emitting fluorescent substance is substantially represented by a formula, (Gd1-x-yMEuy)2O3 (M is at least a kind of element selected from Al and Ca; x and y are numbers satisfying inequalities: 0.00001<=x<=0.1 and 0.005<=y<=0.2), has a crystal structure whose main phase is a monoclinic system, and has an emission spectrum distribution whose first peak having the largest strength ratio exists in a range of 615-630nm, when excited with a mercury bright line at 254nm.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a red- or deep-red emitting phosphor activated with Eu and a fluorescent lamp using the same. More specifically, the present invention relates to a three-wavelength light emitting device having high luminous efficiency and high color rendering. TECHNICAL FIELD The present invention relates to a red- or deep-red light emitting phosphor suitable for an area emission type fluorescent lamp, and a fluorescent lamp using the same.

[0002]

2. Description of the Related Art In recent years, so-called three-wavelength band emission type fluorescent lamps have become mainstream as fluorescent lamps for general illumination. In this type of fluorescent lamp, three types of phosphors of blue light emission, green light emission, and red light emission having a relatively narrow band emission spectrum distribution are mixed at an arbitrary ratio, and the mixed phosphors produce the required fluorescent film (fluorescent light). The body layer) is formed. In addition, recently, in order to further improve color rendering properties, a three-wavelength band emission type fluorescent lamp using a mixed phosphor in which a blue-green light emitting phosphor and a deep red light emitting phosphor are mixed has also appeared.

By the way, as a red light emitting phosphor for the above-mentioned three-wavelength band emission type fluorescent lamp, Eu activated yttrium oxide phosphor ((Y, Eu) ₂ O ₃ ) and a deep red light emitting phosphor are used. As a manganese-activated germanate phosphor (3.
_{5MgO · 0.5MgF 2 · GeO 2:} Mn) is generally used.

However, in the three-wavelength band emission type fluorescent lamp using the above-mentioned red light emitting phosphor and deep red light emitting phosphor, the special color rendering index R9 of the red component is about 20 to 40, and the average color rendering index is It is pointed out that it is very low compared to Ra and other special color rendering indices. The cause is that the emission peak wavelength of (Y, Eu) ₂ O ₃ which is a red light emitting phosphor is 611 nm, and 3.5MgO ・ 0.5MgF ₂・ GeO which is a deep red light emitting phosphor.
₂ : This is because the emission peak wavelength of Mn is 658 nm, and since the emission peak wavelength of the deep red light-emitting phosphor is too high, the visual effect cannot be sufficiently obtained.

On the other hand, the special color rendering index of the red component
It is known that the most effective emission peak for improving R9 is 620 to 630 nm. Here, as a phosphor having an emission peak in this wavelength range, an Eu-activated gadolinium oxide phosphor ((Gd, Eu) ₂ O ₃ ) is known. This (Gd, Eu) ₂
The O ₃ phosphor has two types of crystal structures depending on the firing temperature, and becomes a cubic system at 1250 ° C or lower and a monoclinic system at 1250 ° C or higher. When the crystal structure of (Gd, Eu) ₂ O ₃ is cubic, the emission peak wavelength is 611 nm, whereas when it is monoclinic, the emission peak wavelength is 623 nm. As described above, the monoclinic (Gd, Eu) ₂ O ₃ phosphor has an emission spectrum distribution effective for improving the special color rendering index R9 of the red component. However, the monoclinic (Gd, Eu) ₂ O ₃ phosphor has a low emission efficiency of about 20% that of (Y, Eu) ₂ O ₃ and is a deep red-emitting phosphor of a three-wavelength band emission type fluorescent lamp. When used as the above, there is a problem that the brightness of the fluorescent lamp is significantly reduced.

[0006]

As described above, the conventional three-wavelength band emission type fluorescent lamp has a problem that the special color rendering index R9 of the red component is low, and the special color rendering index R9 of the red component is low. Has an emission spectrum distribution suitable for improvement
The (Gd, Eu) ₂ O ₃ phosphor has low emission efficiency, and when this phosphor is used in a three-wavelength band emission type fluorescent lamp, there is a problem that the brightness is significantly reduced.

The present invention has been made in order to solve such a problem, and has a high color rendering property, a high luminous efficiency, and a red or deep red emission suitable for a three-wavelength band emission type fluorescent lamp. It is an object to provide a phosphor and a fluorescent lamp using such a phosphor.

[0008]

The red or deep red light-emitting phosphor of the present invention has the general formula: (Gd _1-xy M _x Eu _y ) ₂ O ₃ (1) (where M is Al And at least one element selected from Ga, where x and y are 0.00001 ≤ x ≤ 0.
1, a number satisfying 0.005 ≦ y ≦ 0.2), the main phase of the crystal structure of which is a monoclinic system, and the phosphor was excited by the 254 nm mercury emission line. In the emission spectrum distribution at that time, the first peak having the largest intensity ratio is characterized by being present in the range of 615 to 630 nm.

The first fluorescent lamp of the present invention is a fluorescent lamp having a fluorescent layer deposited on the inner wall surface of a glass tube, wherein the fluorescent layer contains at least red or deep red of the fluorescent substance of the present invention. It is characterized in that it is contained as a light emitting component.

The second fluorescent lamp is formed on the inner wall surface of the glass tube and has a fluorescent layer containing a blue light emitting phosphor, a green light emitting phosphor and a red or deep red light emitting phosphor. In the above, the phosphor layer contains the phosphor of the present invention as the red to deep red light emitting phosphor.

Further, the third fluorescent lamp has a phosphor layer which is formed on the inner wall surface of the glass tube and contains a blue light emitting phosphor, a green light emitting phosphor, a red light emitting phosphor and a deep red light emitting phosphor. In the fluorescent lamp to do, the phosphor layer,
The deep red light-emitting phosphor contains the phosphor of the present invention.

The phosphor of the present invention comprises a Eu-activated gadolinium oxide phosphor whose main phase of the crystal structure is a monoclinic system, and Al and
At least one M element selected from Ga is contained in the range of 0.00001 to 0.1 as the value of x in the above formula (1). Here, the Eu-activated gadolinium oxide phosphor according to the present invention may be such that the main phase of the crystal structure is a monoclinic system,
Specifically, 50% or more may be monoclinic. Depending on the usage of the Eu-activated gadolinium oxide phosphor, 70% or more of the crystal structure is more preferably a monoclinic system, and more preferably by substantially making the crystal structure a monoclinic system. is there.

The above M element has a monoclinic system as a main phase.
It is an element that contributes to the improvement of the luminous efficiency of the Eu-activated gadolinium oxide phosphor, and the content composition ratio thereof is important in the present invention. When the content of M element is less than 0.00001 as the value of x, the effect of improving the luminous efficiency cannot be sufficiently obtained, and when it exceeds 0.1, premature blackening occurs when used in a fluorescent lamp, and fluorescence is increased. This will cause deterioration of the lamp characteristics. Therefore, the content of M element is 0.00001 as the value of x in equation (1).
The range is to 0.1. More preferable value of x is 0.001 to 0.0
It is in the range of 1.

The composition of Eu as the activator also greatly contributes to the emission efficiency of the Eu-activated gadolinium oxide phosphor having a monoclinic system as the main phase, and the value of y in the above formula (1) is If it is less than 0.005, sufficient luminous efficiency cannot be obtained. On the contrary, if it exceeds 0.2, the luminous efficiency is lowered due to concentration quenching. Therefore, Eu
The value of y in Eq. (1) should be in the range of 0.005 to 0.2. The more preferable y value is in the range of 0.01 to 0.1.

Since the main phase of the crystal structure of the Eu-activated gadolinium oxide phosphor according to the present invention is composed of a monoclinic system, the intensity ratio is the highest in the emission spectrum distribution when excited by the mercury emission line of 254 nm. The first big peak is 615
It exists in the range of ~ 630 nm and emits red to deep red light. In the case of including a cubic system or the like, the second peak having the next largest intensity ratio exists in the above emission spectrum distribution, for example, in the range of 605 to 615 nm, but the first peak having the largest intensity ratio is the above. There is no particular problem if the conditions are satisfied.

The red or deep red light-emitting phosphor according to the present invention is likely to have a cubic crystal structure, and therefore the manufacturing method is also important. In particular, the firing temperature at the time of synthesizing the phosphor is important, and at 1250 ° C or lower, the crystal structure is all cubic,
At 1250 to 1300 ° C, cubic system and monoclinic system coexist. Therefore, in the present invention, baking is performed at a temperature of at least 1250 ° C or higher, and more preferably 1300 ° C or higher. 1300
By firing at a temperature of not less than ° C, an Eu-activated gadolinium oxide phosphor substantially consisting of a monoclinic system can be obtained. That is, first, each starting material of the phosphor represented by the above formula (1) is prepared. Here, as the Gd source, a compound such as an oxide, a hydroxide, or a carbonate that easily becomes a Gd oxide at high temperature is used, and as the Eu source, an oxide, a carbonate, or the like is used. Also, Al ₂ O ₃ and AlCl ₃ are used as the Al source.
Gd ₂ O ₃ or GdF ₃ is used as the source.

A predetermined amount of these starting materials are weighed and mixed sufficiently. At this time, each of the mixed amounts does not necessarily have to be a stoichiometric composition for the reason of accelerating the phosphor synthesis reaction and improving the yield of the phosphor. By the way, the composition ratio of each element in the raw material and the composition ratio of each element in the phosphor after synthesis,
Not necessarily a match.

Next, the above raw material mixture is placed in a heat-resistant container such as a crucible, and baked in the atmosphere at a temperature of 1250 ° C. or higher, more preferably 1300 ° C. or higher for 2 to 10 hours as described above. . After crushing the fired product, it is thoroughly washed with pure water to obtain the phosphor of the present invention.

The fluorescent lamp of the present invention comprises an Eu-activated gadolinium oxide phosphor whose main phase is a monoclinic system whose substantial composition is represented by the above formula (1) as at least a red or deep red light emitting component. It has a phosphor layer to be contained.

When the fluorescent lamp of the present invention is applied to a three-wavelength band emission type fluorescent lamp, the fluorescent material of the present invention is used as a red or deep red light emitting fluorescent material together with a blue light emitting fluorescent material and a green light emitting fluorescent material. A conventional phosphor may be used as the red light emitting phosphor, and the phosphor of the present invention may be used as the deep red light emitting phosphor. The phosphor of the present invention is preferably used as a deep red light-emitting phosphor in order to enhance the color rendering properties while satisfying the high emission efficiency of the three-wavelength band emission type fluorescent lamp. In this case, the deep red emitting phosphor is
It is preferably used as about 5 to 20% of the whole phosphor. In addition, various known phosphors can be used as the blue light emitting phosphor, the green light emitting phosphor, and the red light emitting phosphor, and in order to further enhance the color rendering property, for example, blue light emitting phosphor is used as another light emitting component. It is also possible to add a phosphor or the like.

[0021]

The red or deep red light emitting phosphor of the present invention has an emission spectrum distribution suitable for exhibiting a high color rendering property and has an optimized composition ratio of Eu as an activator. Since it contains a small amount of Al and Ga, a high luminous efficiency can be stably obtained. Such a red or deep red emitting phosphor exhibits excellent luminous efficiency and high color rendering properties even when used as a phosphor layer of a fluorescent lamp, and in particular, a significant improvement effect on the special color rendering index R9 of the red component. Indicates. Therefore, it is possible to obtain a fluorescent lamp that satisfies both high luminous efficiency and high color rendering.

[0022]

EXAMPLES Examples of the present invention will be described below.

Example 1 First, 355.3 g of Gd ₂ O ₃ was used as each starting material of the phosphor.
7.0 g of Eu ₂ O ₃ was weighed and completely dissolved in nitric acid. Pure water is added to this to dilute it, and oxalic acid is added to this solution to form a precipitate immediately. Oxalic acid was added until no precipitate was formed, the precipitate was collected, placed in an alumina crucible, and calcined at 800 ° C in the atmosphere. The calcined product was crushed, sieved, and then subjected to compositional analysis. As a result, (Gd _0.98 Eu
It was confirmed that _0.02 ) ₂ O ₃ was produced.

Next, Al _{2 is added to} the above (Gd _0.98 Eu _0.02 ) ₂ O _3.
After 0.1 g of O ₃ was mixed, this mixture was put into an alumina crucible and fired at 1400 ° C. in the atmosphere. The fired product thus obtained was pulverized, washed thoroughly with pure water, dried and sieved to obtain the desired phosphor.

When the composition of the thus obtained phosphor was analyzed, it was confirmed that it had a composition represented by (Gd _0.9799 Al _0.0001 Eu _0.02 ) ₂ O ₃ . In addition, for comparison with the present invention, (Gd _0.98 Eu before mixing Al ₂ O _3
0.02 ) ₂ O ₃ was fired in the air at 1400 ° C., and then treated in the same manner to produce a phosphor.

According to the above embodiment (Gd _0.9799 Al _0.0001 Eu
_The emission brightness of the _0.02 ) ₂ O ₃ phosphor excited by the 254 nm mercury emission line was measured.
At 0%, it reached 210%. Next, the emission spectrum distribution of the phosphor according to the above example was measured by excitation with a 254 nm mercury emission line. The obtained emission spectrum distribution is shown in FIG.
The wavelength of the first peak having the highest emission intensity was 623 nm, and the wavelength of the second highest peak was 616 nm. Al
No particular change was observed in the emission spectrum distribution due to the inclusion of, and it was confirmed that the emission spectrum distribution is suitable for improving the special color rendering index R9 of the red component.

Further, X-ray diffraction of the phosphor according to the above example was performed. The measurement result is shown in FIG. As is clear from FIG. 2, the crystal structure of the phosphor according to the above-mentioned embodiment is a typical monoclinic system. For comparison, a phosphor prepared by mixing (Gd _0.98 Eu _0.02 ) ₂ O ₃ with 0.1 g of Al ₂ O ₃ in the atmosphere at 1200 ° C. and then similarly treating X-ray diffraction was performed. The measurement result is shown in FIG. As is clear from FIG. 3, the crystal structure of the phosphor fired at 1200 ° C. is cubic. Moreover, the emission spectrum distribution was different from that in the above-mentioned Examples, and the wavelength of the first peak having the largest emission intensity was 611 nm.

Example 2 308.1 g of Gd ₂ O ₃ and Eu ₂ O were used as starting materials for the phosphor.
52.8 g of ₃ was weighed and completely dissolved in nitric acid. Pure water is added to this to dilute it, and oxalic acid is added to this solution to form a precipitate immediately. Oxalic acid was added until no precipitate was formed, the precipitate was collected, placed in an alumina crucible, and calcined at 900 ° C in the atmosphere. This calcined product was crushed, sieved, and then subjected to compositional analysis. As a result, (Gd _0.85 Eu _0.15 ) ₂
It was confirmed that O ₃ was generated.

Next, Ga _{2 is} added to the above (Gd _0.85 Eu _0.15 ) ₂ O _3.
After 0.1 g of O ₃ was mixed, the mixture was put into an alumina crucible and fired at 1350 ° C. in the atmosphere. The fired product thus obtained was pulverized, washed thoroughly with pure water, dried and sieved to obtain the desired phosphor.

The results of composition analysis of the thus obtained phosphor was confirmed to have a composition represented by _{(Gd 0.849 Ga 0.001 Eu 0.15)} 2 O 3. In addition, for comparison with the present invention, (Gd _0.85 Eu before mixing Ga ₂ O _3
0.15 ) ₂ O ₃ was fired in the air at 1350 ° C., and then treated in the same manner to produce a phosphor.

According to the above embodiment (Gd _0.849 Ga _0.001 Eu
_The emission brightness of the _0.15 ) ₂ O ₃ phosphor excited by the mercury emission line at 254 nm was measured.
At 0%, it reached 200%. Also, the emission spectrum distribution of the phosphor according to the above-described example has a wavelength of the first peak with the largest emission intensity of 623 nm, which is suitable for improving the special color rendering index R9 of the red component, as in Example 1. It was confirmed that it had an emission spectrum distribution. Further, when the X-ray diffraction of the phosphor according to this example was performed, the crystal structure was a monoclinic system as in Example 1.

Example 3 326.3 g of Gd ₂ O ₃ and Eu ₂ O ₃ were used as starting materials for the phosphor.
35.2 g of ₃ was weighed and completely dissolved in nitric acid. Pure water is added to this to dilute it, and when dimethyl oxalate is added to this solution, a precipitate is immediately formed. Dimethyl oxalate was added until no precipitate was formed, and the precipitate was collected, placed in a quartz crucible, and calcined at 700 ° C in the atmosphere. After crushing this sinter and sieving it, the composition was analyzed.
It was confirmed that _0.90 Eu _0.10 ) ₂ O ₃ was generated.

Next, AlCl is added to the above (Gd _0.90 Eu _0.10 ) ₂ O ₃ .
After mixing 0.5 g of ₃ , the mixture was put in a quartz crucible and fired at 1500 ° C. in the atmosphere. The fired product thus obtained was pulverized, washed thoroughly with pure water, dried and sieved to obtain the desired phosphor.

When the composition of the thus obtained phosphor was analyzed, it was confirmed that it had a composition represented by (Gd _0.8995 Al _0.0005 Eu _0.10 ) ₂ O ₃ . Also, for comparison with the present invention, (Gd _0.90 E before mixing with AlCl ₃
u _0.10 ) ₂ O ₃ was fired in the air at 1500 ° C., and then treated in the same manner to produce a phosphor.

According to the above embodiment (Gd _0.8995 Al _0.0005 Eu
_The emission brightness of the _0.10 ) ₂ O ₃ phosphor excited by the 254 nm mercury emission line was measured.
At 0%, it reached 230%. Also, the emission spectrum distribution of the phosphor according to the above-mentioned example has a wavelength of the first peak with the highest emission intensity of 623 nm, which is suitable for improving the special color rendering index R9 of the red component, as in Example 1. It was confirmed that it had an emission spectrum distribution. Further, when the X-ray diffraction of the phosphor according to this example was performed, the crystal structure was a monoclinic system as in Example 1.

Examples 4 to 8 In the same manner as in Example 1, Eu activated gadolinium oxide phosphors whose compositions are shown in Table 1 were prepared. The emission luminance of each of these phosphors was measured by excitation with a 254 nm mercury emission line. The results are also shown in Table 1. The emission brightness is (Gd
_0.95 Eu _0.05 ) ₂ O _{3 It} is shown as a value with the emission brightness of the phosphor taken as 100%.

[0037]

[Table 1] Example 9 (Sr, Ca, Ba, Eu) ₁₀ (PO ₄ ) ₆ C as a blue light emitting phosphor
l ₂ , green emission phosphor (La, Ce, Tb) PO ₄ , red emission phosphor (Y, Eu) ₂ O ₃ , and deep red emission phosphor according to Example 1 (Gd _0.9799 Al
_0.0001 Eu _0.02 ) ₂ O ₃ phosphors are mixed so that the mixing ratio becomes 5% of the whole, and a three-wavelength emission type fluorescent lamp (straight tube type)
A 20 W fluorescent lamp FL20SS) was manufactured by a conventional method so that the correlated color temperature was 5000K. For comparison with the present invention, a fluorescent lamp using an Eu-activated gadolinium oxide phosphor containing no Al as a deep red light emitting phosphor and a fluorescent lamp not using a deep red light emitting phosphor were manufactured.

When the special color rendering index R9 of the red component of the fluorescent lamps of these examples and comparative examples was measured, the value of R9 of the fluorescent lamps of the examples was 50, and the Eu-activated gadolinium oxide fluorescent material containing no Al was found. Of fluorescent lamps using the body
The value of R9 is 35, that of a fluorescent lamp that does not use a deep red emitting phosphor.
The value of R9 was 30. The initial total luminous flux of a fluorescent lamp is 100% that of a fluorescent lamp that does not use a deep red light-emitting phosphor.
Then, the fluorescent lamp according to the example is 101, and the fluorescent lamp using the Eu-activated gadolinium oxide phosphor containing no Al is
It was 80. Thus, according to the three-wavelength band emission type fluorescent lamp of this embodiment, in addition to improving the initial total luminous flux by 1%,
We were able to improve the special color rendering index R9 by 20 points.

Example 10 3 (Ba, Mg, Eu, Mn) O.8Al ₂ O ₃ as a blue light emitting phosphor,
(La, Ce, Tb) PO ₄ was used as the green light emitting phosphor, (Y, Eu) ₂ O ₃ was used as the red light emitting phosphor, and further as the deep red light emitting phosphor according to Example 2 (Gd _0.849 Ga _0.001 EU
_0.15 ) ₂ O ₃ phosphors are mixed so that the mixing ratio is 10% of the whole, and the three-wavelength band emission type fluorescent lamp (circular tube type 30W fluorescent lamp FCL30) is used in a conventional method to obtain a correlated color temperature of
It was manufactured to be 0K. For comparison with the present invention, a fluorescent lamp using an Eu-activated gadolinium oxide phosphor containing no Al as a deep red light emitting phosphor and a fluorescent lamp not using a deep red light emitting phosphor were manufactured.

When the special color rendering index R9 of the red component of the fluorescent lamps of these examples and comparative examples was measured, the value of R9 of the fluorescent lamps of the examples was 60, and the Eu-activated gadolinium oxide fluorescent material containing no Al was used. Of fluorescent lamps using the body
The value of R9 is 35, that of a fluorescent lamp that does not use a deep red emitting phosphor.
The value of R9 was 25. The initial total luminous flux of a fluorescent lamp is 100% that of a fluorescent lamp that does not use a deep red light-emitting phosphor.
Then, the fluorescent lamp according to the example is 102, and the fluorescent lamp using the Eu-activated gadolinium oxide phosphor containing no Al is
It was 75. As described above, according to the three-wavelength band emission type fluorescent lamp of this embodiment, in addition to improving the initial total luminous flux by 2%,
We were able to improve the special color rendering index R9 by 25 points.

Examples 11 to 15 Using the Eu-activated gadolinium oxide phosphors produced in Examples 4 to 8 as deep red light-emitting phosphors, Example 9
In the same manner as above, three wavelength band fluorescent lamps were produced. The special color rendering index R9 of the red component of each of these fluorescent lamps was measured. The results are shown in Table 2.

[0042]

[Table 2]

[0043]

As described above, according to the present invention,
It is possible to provide a red- or deep-red emitting phosphor having a stable high emission efficiency and an emission spectrum distribution optimal for exhibiting a high color rendering property. The phosphor of the present invention exhibits excellent luminous efficiency and high color rendering properties even when used as a phosphor layer of a fluorescent lamp, and in particular exhibits a significant improvement effect on the special color rendering index R9 of the red component, It is possible to provide a fluorescent lamp that satisfies both high luminous efficiency and high color rendering.

[Brief description of drawings]

FIG. 1 is a diagram showing an emission spectrum distribution of a phosphor according to an embodiment of the present invention.

FIG. 2 is a diagram showing an X-ray diffraction result of a phosphor according to an example of the present invention.

FIG. 3 is a diagram showing an X-ray diffraction result of a phosphor according to a comparative example.

Claims (4)

[Claims] 1. A general formula: (Gd _1-xy M _x Eu _y ) ₂ O ₃ (wherein M represents at least one element selected from Al and Ga, and x and y are each 0.00001 ≦ x ≤ 0.
1, a number satisfying 0.005 ≦ y ≦ 0.2), the main phase of the crystal structure of which is a monoclinic system, and the phosphor was excited by the 254 nm mercury emission line. In the emission spectrum distribution at that time, the first peak having the largest intensity ratio exists in the range of 615 to 630 nm. 2. A fluorescent lamp comprising a phosphor layer deposited on an inner wall surface of a glass tube, wherein the phosphor layer contains at least the phosphor according to claim 1 as a red to deep red light emitting component. Characteristic fluorescent lamp. 3. A fluorescent lamp having a phosphor layer formed on an inner wall surface of a glass tube and containing a blue light emitting phosphor, a green light emitting phosphor and a red or deep red light emitting phosphor, wherein the phosphor layer is A fluorescent lamp comprising the phosphor according to claim 1 as the red to deep red light emitting phosphor. 4. A fluorescent lamp having a phosphor layer formed on an inner wall surface of a glass tube and containing a blue light emitting phosphor, a green light emitting phosphor, a red light emitting phosphor and a deep red light emitting phosphor. A fluorescent lamp, wherein the body layer contains the phosphor according to claim 1 as the deep red light emitting phosphor.