JP3790854B2 - Strontium titanate phosphor - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention is an electron beam, is irradiated with ultraviolet rays or the like relates to a phosphor which exhibits red light emission with high brightness and, more particularly, to rare-earth Katsuchi Tan strontium phosphor.
[0002]
[Prior art]
Conventionally, many practical phosphors that emit light with high brightness when irradiated with an electron beam contain sulfur as a component. This type of phosphor is applied as a fluorescent film in a vacuum envelope equipped with an electron beam source and used as a device such as a fluorescent display tube or a cathode ray tube. , Scatter and degrade the electron beam source of the device. Therefore, an oxide-based phosphor containing no sulfur is desired.
[0003]
As one of the phosphors satisfying such a demand, an alkaline earth titanate phosphor activated with a rare earth element has been proposed (see JP-A-8-85788).
In addition to Ce, Tb, Eu, Tm, and the like as an activator, this phosphor further includes a Group 3 element of the periodic table such as Al, Ga, etc. It is known to emit light with a corresponding emission color.
[0004]
[Problems to be solved by the invention]
However, this rare earth element-activated alkaline earth titanate phosphor is not always sufficient in terms of light emission luminance, and development of a high-luminance phosphor that can be used practically has been demanded.
Accordingly, the present invention is intended to solve the above problems and provide a high-brightness rare earth element-activated divalent metal titanate phosphor that can withstand practical use.
[0005]
[Means for Solving the Problems]
In order to solve the above-mentioned problems, the present inventor conducted intensive studies on additives and the like added to the phosphor raw material during the production of the divalent metal titanate phosphor activated with rare earth elements. Among the element-activated divalent metal titanate phosphors, it is found that when a predetermined amount of Gd and / or Dy element is added to the strontium titanate phosphor, the emission luminance of the phosphor is remarkably improved, and the present invention is completed. It came to.
[0006]
The configuration of the present invention is described as follows.
(1) the composition formula _{Sr TiO 3: Pr, M '} , features and to Ruchi Tan strontium phosphor that is represented by Re. (However, M 'respectively represent Al and / or Ga, Re is Gd and / or Dy to).
[0008]
(2) titanium strontium phosphor according to (1), wherein the content of the Gd is 3 × 10 ^-4 to 10 mol% (1 × 10 ^-2 to 2 mol%).
( 3 ) The Dy content is 7 × 10 ⁻⁴ to 4 × 10 ⁻¹ mol% ( more preferably 2 × 10 ⁻³ to 2 × 10 ⁻¹ mol%). (1) or strontium titanate phosphor according to (2).
[0009]
(4) titanium acid according to any one of the content of the Pr is characterized in that 0.01 to 2 mol% in terms of Pr ₂ O ₃ (1) ~ (3) Strontium phosphor.
(5) the Al and / or the content of Ga is characterized by a 0.05 to 80 mol% (1) to titanium strontium phosphor according to any one of (4).
[0010]
DETAILED DESCRIPTION OF THE INVENTION
The following raw materials are used for the production of the phosphor of the present invention.
(i) oxide or Sr compounds which form oxides of Sr by firing of Sr
(ii) TiO ₂ or a Ti compound that forms an oxide of Ti by firing
(iii) Pr-containing compounds such as Pr (NO ₃ ) ₃
(iv) Al and Ga compounds such as Al ₂ (SO ₄ ) ₃ and Ga (NO ₃ ) ₃
(v) Gd and Dy compounds such as GdCl ₃ and Dy (NO ₃ ) ₃
In the phosphor of the present invention, the raw materials are stoichiometrically weighed so as to have the compositional formula SrTiO ₃ : Pr, M ′, Re, mixed, filled in a heat-resistant container, It can manufacture by baking at the temperature of 1000-1400 degreeC over 0.5 to 10 hours.
[0012]
In this way, rare-earth Katsuchi Tan strontium phosphor of the present invention to be produced, in particular acceleration voltage is less 20 KV, showed light emission of high luminance at a relatively low acceleration voltage electron beam excitation under low voltage electron beam In addition to being recommended for fluorescent films of electron beam excitation displays such as excitation fluorescent display tubes and field emission displays (FEDs), it emits light with high brightness even under ultraviolet excitation, so it can also be used for fluorescent lamps.
[0013]
In the present invention, in order to ensure the light emission luminance of the phosphor, the activator praseodymium may be added in an amount of 0.01 to ₂ mol% in terms of Pr ₂ O _3. not desirable.
[0014]
In the phosphor of the present invention, as an activator, even if rare earth elements other than Pr such as Ce, Tb, Eu, and Tm described in JP-A-8-85788 are added, Compared with the case of activation, sufficient light emission luminance cannot be obtained, and even if Gd and / or Dy is added as Re to this, the light emission luminance cannot be improved.
[0015]
FIG. 1 shows an example of a phosphor according to the present invention. In a SrTiO ₃ : Pr, Al, Gd phosphor, the amount of Gd added to the phosphor (Re amount) and each phosphor was excited by an electron beam of 15 KV. It is the graph which showed the correlation with the light emission luminance at the time, and the light emission luminance on the vertical axis shows the relative value of each phosphor when Gd is not added and the light emission luminance of the conventional phosphor is 100 It is. At this time, the amount of Pr as an activator of each phosphor was 0.2 mol% in all cases.
[0016]
As can be seen from FIG. 1, when Re is Gd, Re (Gd) is not added when the amount of Gd added is in the range of 3 × 10 ⁻⁴ to 10 mol% (value converted to Gd ₂ O ₃ ). a high luminance than the conventional rare-earth Katsuchi Tan strontium phosphor, further, when the addition amount of Re (Gd) is in the range of 1 × 10 ^-2 to 2 mol%, than the phosphor of the conventional same type Was also particularly bright. And it was confirmed that this tendency shows the same tendency even if the concentration of Pr of the activator is changed.
[0017]
FIG. 2 shows an example of the phosphor according to the present invention. In the SrTiO ₃ : Pr, Al, Dy phosphor, the amount of Re (Dy) added to the phosphor and each phosphor was excited with an electron beam of 15 KV. It is the graph which illustrated the correlation with the light emission luminance at the time, and the light emission luminance on the vertical axis is the relative value of each phosphor when the light emission luminance of the conventional phosphor not added with Re (Dy) is 100. It is shown. At this time, the addition amount of Pr as an activator of each phosphor was 0.2 mol%.
[0018]
Further, as can be seen from FIG. 2, when Re is Dy, the amount of Re (Dy) added is in the range of 7 × 10 ⁻⁴ to 4 × 10 ⁻¹ mol% (value converted to Dy ₂ O ₃ ). in inner, a higher luminance than the conventional rare-earth Katsuchi Tan strontium phosphor without the addition of Re (Dy). Furthermore, when the addition amount of Re (Dy) was 2 × 10 ⁻³ to 2 × 10 ⁻¹ mol%, the brightness was particularly higher than that of the conventional phosphor of the same type.
[0019]
FIG. 3 illustrates an emission spectrum when an SrTiO ₃ : Pr, Al, Gd phosphor, which is an example of the phosphor of the present invention, is excited with an electron beam of 15 KV. As is clear from FIG. 3, this phosphor exhibited an emission spectrum having its peak wavelength at about 620 nm and exhibited red emission. FIG. 3 exemplifies a phosphor to which Gd is added as Re. Even when Re is Dy, the emission spectrum is almost the same as in FIG.
[0020]
【Example】
Hereinafter, the present invention will be described in more detail with reference to examples.
Example 1
SrCO ₃ : 147.6 g
TiO ₂ : 79.9 g
Al ₂ O ₃ : 15.3 g
Gd ₂ O ₃ : 0.73 g (0.2 mol%)
PrCl ₃ · 7H ₂ 0: 0.75 g (0.2 mol%)
The phosphor raw materials were sufficiently mixed, packed in an alumina crucible, and fired at 1200 ° C. for 3 hours in an electric furnace to obtain the SrTiO ₃ : Pr, Al, Gd phosphor of Example 1.
[0021]
(Example 2)
SrCO ₃ : 147.6 g
TiO ₂ : 79.9 g
Al ₂ O ₃ : 15.3 g
Dy ₂ O ₃ : 0.11 g (0.03 mol%)
PrCl ₃ .7H ₂ O: 0.75 g (0.2 mol%)
The phosphor raw materials were sufficiently mixed, packed in an alumina crucible, placed in an electric furnace at 1200 ° C. for 3 hours, and baked to obtain the SrTiO ₃ : Pr, Al, Dy phosphor of Example 1.
[0022]
(Comparative Example 1)
SrCO ₃ : 147.6 g
TiO ₂ : 79.9 g
Al ₂ O ₃ : 15.3 g
PrCl ₃ .7H20: 0.75 g (0.2 mol%)
The phosphor raw materials were sufficiently mixed, packed in an alumina crucible, placed in an electric furnace at 1200 ° C. for 3 hours, and baked to obtain the SrTiO ₃ : Pr, Al phosphor of Comparative Example 1.
[0023]
Next, each of the phosphors of Examples 1 and 2 and Comparative Example 1 was irradiated with an electron beam of 15 KV, and the emission luminance at that time was compared. When the emission luminance of the phosphor of the comparative example was 100, The relative light emission luminances of the phosphors of Examples 1 and 2 exhibited 160 and 130 red light emission, respectively.
[0024]
【The invention's effect】
By adopting the above-described configuration, the present invention exhibits a brighter red light emission, especially under electron beam or ultraviolet light excitation, as compared with conventional rare earth activated alkaline earth titanate phosphors. It is useful as a phosphor for use in fluorescent lamps.
[Brief description of the drawings]
FIG. 1 is a graph showing the correlation between the amount of rare earth element (Gd) added to the phosphor of the present invention and light emission luminance.
FIG. 2 is a graph showing the correlation between the amount of rare earth element (Dy) added to the phosphor of the present invention and emission luminance.
FIG. 3 is a graph illustrating an emission spectrum of the phosphor of the present invention.

Claims (3)

Formula _{Sr TiO 3: Pr, M '} , features and to Ruchi Tan strontium phosphor that is represented by Re. (However, M 'respectively represent Al and / or Ga, Re is Gd and / or Dy to). Titanium strontium phosphor according to claim 1, wherein the content of the Gd is 3 × 10 ^-4 to 10 mol%. Titanium strontium phosphor according to claim 1 or 2, wherein the content of the Dy is 7 × 10 ^-4 ~4 × 10 ^-1 mol%.

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