JP2006265396A - Red phosphor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a red phosphor emitting light by excitation by electron beam, especially to provide a red phosphor suitable for field emission type display (FED). <P>SOLUTION: The invention relates to the red phosphor used for electron beam-excited light emitting device represented by formula (Y<SB>1-x-y-z</SB>Eu<SB>x</SB>Zn<SB>y</SB>Zr<SB>z</SB>)<SB>2</SB>O<SB>3</SB>(in the formula, 0.01≤x≤0.3, 0.0001≤y≤0.01, 0.0001≤z≤0.03), wherein a part of yttrium is substituted with europium, zinc and zirconium. The red phosphor has improved luminescence intensity by irradiation with the electron beam and has the luminescence intensity never obtained in a single zinc-based system by using zinc and zirconium as a coactivator. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a red phosphor used for an electron beam-excited light emitting device such as a field emission display (FED).

As a red phosphor used in an electron beam-excited light emitting device, yttrium oxide (Y, Eu) ₂ O ₃ activated with europium is known. Although this emits red light when it is irradiated with an electron beam by substituting a part of yttrium with europium, the light emission luminance is not sufficient, and studies for improving the light emission luminance have been made. For example, (Y, Eu, Zn) ₂ O ₃ is known in which emission luminance is improved by further substituting part of yttrium with zinc and performing co-activation (see Patent Documents 1 and 2).

JP 2000-319654 A JP 2002-235078 A

Although (Y, Eu, Zn) ₂ O ₃ described in Patent Documents 1 and 2 is improved in red light emission luminance as compared with (Y, Eu) ₂ O ₃ , red light emission of a field emission display (FED). For use as an element, further improvement in light emission luminance is required.

The inventors of the present invention have made various studies in order to find a red phosphor having a further improved luminance. When the above (Y, Eu, Zn) ₂ O ₃ is used together with zirconium as a coactivator. The present inventors have found that the light emission luminance by electron beam irradiation is further improved and that the light emission luminance that cannot be obtained by the zinc co-activation system can be obtained.

  That is, the present invention is an electron beam-excited red phosphor characterized in that yttrium oxide is used as a base and a part of yttrium is substituted with europium, zinc, and zirconium.

  In the red phosphor of the present invention, by further using zirconium together with zinc as a coactivator, the light emission luminance by electron beam irradiation increases, and light emission luminance that cannot be obtained with a zinc single system is obtained.

  The present invention is an electron beam-excited red phosphor, characterized in that yttrium oxide is used as a base material and a part of yttrium is substituted with europium, zinc, and zirconium.

The substitution amount of europium used as an activator and zinc and zirconium used as a co-activator is 0 when the composition of the phosphor is represented by the general formula (Y1 _-xyz Eu _x Zn _y Zr _z ) ₂ O _3. .01 ≦ x ≦ 0.3, 0.0001 ≦ y ≦ 0.01, 0.0001 ≦ z ≦ 0.03 are preferable, and 0.02 ≦ x ≦ 0.2 and 0.0005 ≦ are more preferable. It is y <= 0.005 and 0.0005 <= z <= 0.01.

  If the substitution amount x of europium used as the activator is less than the above range, the color purity of the luminescent color tends to be inferior.

  In addition, if the substitution amounts y and z of zinc and zirconium used as a co-activator are less than the above range, it is difficult to confirm the superior improvement effect. descend.

  Furthermore, in the present invention, the effect of improving the luminance is remarkably preferable when the ratio (z / y) of the substitution amount z of Zr and the substitution amount y of Zn is 1.0 to 6.0.

  A field emission display (FED) is a low voltage type using an electron beam accelerated by a voltage of 100 to 5000 V as an excitation source and a high voltage type 2 using an electron beam accelerated by a voltage of 5000 V or more as an excitation source. Types are being considered. The red phosphor of the present invention can be used in any of the above types because sufficient light emission can be obtained when it is irradiated with an electron beam excited at an acceleration voltage of at least about 3000V.

  The red phosphor of the present invention is, for example, a mixture of raw material powders of yttrium compound, europium compound, zinc compound and zirconium compound as a raw material, optionally in the presence of a flux such as boron, at a temperature of 800 to 1400 ° C. It is obtained by firing in the range. The firing atmosphere is not particularly limited, such as oxidation and reduction, but an oxidation atmosphere is preferable.

  EXAMPLES Hereinafter, although an Example demonstrates this invention, this invention is not limited to these Examples.

Example 1
Yttrium oxide (Y ₂ O ₃ ), europium oxide (Eu ₂ O ₃ ), zinc oxide (ZnO), and zirconium oxide (ZrO ₂ ) in a molar ratio of Y: Eu: Zn: Zr = 0.946: 0.05: 0.002: After blending to 0.002 and mixing in an automatic agate mortar, an appropriate amount of the resulting mixture is put into an alumina crucible and held in the atmosphere at a temperature of 1000 ° C. for 4 hours for baking. did. This was cooled and mixed again, and then calcined by maintaining at a temperature of 1200 ° C. in the atmosphere for 20 hours. This was pulverized in an automatic agate mortar to obtain the phosphor powder of the present invention (Sample A).
When the obtained sample A was irradiated with an electron beam with an electron gun (EFG-7 manufactured by Kimball Physics Inc) in a vacuum chamber of 1.0 × 10 ⁻⁵ Pa or less, it emitted red light, and the relative luminance at that time Was 100 (acceleration voltage 5 kV).

Comparative Example 1 (Zn single system)
Yttrium oxide (Y ₂ O ₃ ), europium oxide (Eu ₂ O ₃ ), and zinc oxide (ZnO) are blended in a molar ratio of Y: Eu: Zn = 0.948: 0.05: 0.002. The same treatment as in Example 1 was performed to obtain a phosphor powder (sample B) as a comparative sample.
The light emission of the obtained sample B by electron beam irradiation was measured by the same method as in Example 1. As a result, the relative luminance was 80.0 (acceleration voltage 5 kV).

Comparative Example 2 (Zr single system)
Yttrium oxide (Y ₂ O ₃ ), europium oxide (Eu ₂ O ₃ ), zirconium oxide (ZrO ₂ ) are blended so that the molar ratio is Y: Eu: Zr = 0.948: 0.05: 0.002. And the process similar to Example 1 was performed and the fluorescent substance powder (sample C) of a comparative sample was obtained.
When light emission of the obtained sample C by electron beam irradiation was measured by the same method as in Example 1, the relative luminance was 70.1 (acceleration voltage 5 kV).

  From the above results, by adding both Zr and Zn, a brightness that could not be obtained when each element was added alone was obtained. In general, even when elements having an additive effect alone are added in combination, the effects are not necessarily added. Therefore, the effect of improving luminance by using Zr and Zn in combination is useful.

  Further, FIG. 1 shows the relationship between the emission luminance of the obtained samples A, B, and C by electron beam excitation and the acceleration voltage. As shown in FIG. 1, the difference in emission luminance between the sample A of the present invention and the comparative samples B and C tends to widen as the acceleration voltage increases. Therefore, the red fluorescence for the low voltage type FED and the high voltage type FED is used. It was found that the phosphor is useful not only as a phosphor but also as a red phosphor utilizing light emission at a high acceleration voltage such as a cathode ray tube.

  The red phosphor of the present invention is useful as a red fluorescent material used for an electron beam-excited light emitting device such as a field emission display (FED). It is also useful as a red fluorescent material used in a cathode ray tube light emitting device having a high acceleration voltage.

It is a graph showing the relationship between the luminescent brightness | luminance by the electron beam excitation of a sample A, B, and C, and an acceleration voltage.

Claims (3)

An electron beam-excited red phosphor characterized in that yttrium oxide is used as a base material and a part of yttrium is substituted with europium, zinc, and zirconium. Formula _{(Y 1-x-y-} z Eu x Zn y Zr z) 2 O 3 ( where, 0.01 ≦ x ≦ 0.3,0.0001 ≦ y ≦ 0.01,0.0001 ≦ z ≦ The electron beam-excited red phosphor according to claim 1, having a composition represented by 0.03). 3. The electron beam excited red phosphor according to claim 2, wherein the compounding ratio (z / y) of Zn and Zr is 1.0 to 6.0.

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