JPS631356B2 - - Google Patents

Description

[Detailed description of the invention]

FIELD OF THE INVENTION The present invention relates to phosphors. In particular, it relates to phosphors used in color cathode ray tubes. It is known that alkaline earth metal sulfide phosphors activated by rare earth or transition metals, particularly CaS and SrS-based phosphors, emit light with high efficiency when stimulated by electron beams. Especially Eu ²⁺ activation or Eu ²⁺
and Ce ³⁺ -coactivated phosphor is a red-emitting phosphor whose main emission wavelength is 650 to 653 nm (CaS system) or 609 to 612 nm (SrS system). On the other hand, the Ce ³⁺ activated phosphor is a green-emitting phosphor whose main emission wavelength is 520-523 nm (CaS system) or 503-506 nm (SrS system).
system). It is also known that the main emission wavelength of (Ca.Sr)S-based phosphors is between that of CaS-based and SrS-based phosphors. Among these phosphors, Eu ²⁺ , Ce ³⁺ activated or
The Eu ²⁺ -activated fluorophore itself has an orange to peach color.
Because it is red, it has the characteristic that even if it is used in a color cathode ray tube without so-called pigments attached, it has the same effect as other red-emitting phosphors with pigments attached. In order to improve the brightness of the above phosphor, Cl,
Doping with halogen elements such as Br and I is disclosed in Japanese Patent Publication No. 38747/1983.
These halogen elements are called co-activators, and rather than emitting light themselves, they play a role in emphasizing the light emission of the activators Eu ²⁺ and Ce ³⁺ . Although Ce ³⁺ itself emits light,
When used together with Eu ²⁺ , it has the role of increasing the luminescence of Eu ²⁺ and is called a sensitizer. Similarly, an attempt to dope the alkaline earth metal sulfide phosphor with P for the purpose of improving the brightness of the phosphor is also disclosed in Japanese Patent Publication No. 38747/1983. However, these effects of improving brightness are still not sufficient. An object of the present invention is to provide a phosphor with improved luminance. The phosphor of the present invention is CaS:Ln, SrS:Ln or (Ca.Sr)S:Ln (Ln is Eu, Ce,
It is characterized by having 50 to 10,000 ppm of Ba added to a phosphor represented by Mn, Cu, and Ag (representing at least one element selected from the group consisting of Mn, Cu, and Ag). Incidentally, a part of Ba in the above-mentioned phosphor may be replaced with Mg. Furthermore, the phosphor of the present invention is characterized in that 100 to 10,000 ppm of phosphorus (P) is added to the phosphor in the presence of a halogen element such as F, Cl, Br, or I. In the phosphor of the present invention, the amount of Eu ²⁺ or Ce ³⁺ is 10 ^-5 to 1 mole of alkaline earth metal sulfide.
Preferably it is 10 ⁻² gram atoms. If the amount is less than this amount, the effect as an activator will be low, and if it exceeds this amount, the luminance of light emission will decrease. The amount of Ba is within the above-mentioned range, and no increase in luminescence intensity is observed whether it is below this range or exceeds this range. The amount of halogen element is preferably from 10 ^-5 to 10 ^-1 gram atoms per mole of alkaline earth metal sulfide. Further, the amount of P is preferably 100 to 10,000 ppm as described above. This is because no increase in luminescence intensity is observed even if the amount is less than this amount or exceeds this amount. The phosphor of the present invention comprises (1) an alkaline earth metal sulfide, or (1') an alkaline earth metal compound and sulfur or a sulfur compound that can be heated together with sulfur or a sulfur compound to form a sulfide, and (2) Eu, It can be obtained by heating Ce, Mn, Cu and/or Ag compounds, and if necessary, (3) phosphorus or phosphorus compounds and (4) halogen alone or halogen compounds. As is clear from the composition of the phosphor, the above alkaline earth metals are
Ca and/or Sr and an amount corresponding to the desired amount
Consists of Ba or Ba and Mg. When PCl ₃ is used as the compound in (3) and (4) above, one type of compound is obtained. When ammonium halide is used as the halogen compound, a portion of the ammonium halide acts as a flux, and a portion of the halogen element tends to be included in the phosphor, which is preferable. The heating temperature is preferably in the range of 1000 to 1400°C. The present invention will be explained below using examples. Examples 1 to 5 Equimolar amounts of CaCO ₃ and SrCO ₃ were weighed, and 0.15 mol % of Eu and 0.15 mol % of Ce were added to 1 mol of this mixture.
A sample in which 0.015 mol% of each was added in the form of oxide and further mixed with BaCO ₃ in the amount shown in Table 1 was heated to 1300℃.
Keep for 10 hours to form oxide. This oxide was kept at 1200℃ for 3 hours in an H ₂ S atmosphere and colored reddish-orange.
Ca _0.5-x/2 Sr _0.5-x/2 Ba _x S: Eu, Ce phosphors were obtained. For comparison, a phosphor was similarly produced without adding any Ba. Each phosphor is connected to a 10 kV electron beam (current density 1
Relative energy efficiency of emission observed when excited at 10 ^-6 A) (relative to that without Ba)
The results of measurements at room temperature and the Ba concentrations actually contained in each phosphor are shown in Table 1. As seen in the table, a significant sensitizing effect of Ba is observed. The emission spectra of each phosphor are the same and exhibit a single peak at 643 nm, as shown in FIG.

[Table] Examples 6 to 10 0.08 mol% of Eu ₂ O ₃ per 1 mol of CaCO ₃ ,
CeO ₂ 0.01 mol % and BaCO ₃ in the amounts listed in Table 2 were mixed and kept at 1300°C for 10 hours, and the resulting oxide was heated to 1200°C in a mixed atmosphere of H ₂ S and H ₂ for 4 hours.
Ca _1-x Ba _x S: Eu, which was kept for a time and colored pink-red.
A phosphor called Ce was obtained. This structure was confirmed by X-rays. For comparison, a phosphor was synthesized in the same manner using a sample that did not contain Ba. Each phosphor was powered at 10kV (current density 1×) at room temperature.
It was excited using an electron beam of 10 ^-6 A), and its emission spectrum and intensity were measured. The emission spectrum of each phosphor is the same, as shown in Figure 2.
It exhibits red emission with a single peak at 652 nm.
The Ba concentration and relative energy efficiency (based on those not containing Ba) are shown in Table 2.

[Table] Examples 11 to 15 Using SrCO ₃ in place of CaCO ₃ in Examples 6 to 10,
Each was colored orange by the same process.
A phosphor of Sr _1-x Ba _x S: Eu, Ce was obtained. The results are shown in Table 3. The emission spectrum of each phosphor is
As shown in FIG. 3, this is orange light emission with a single peak at 613 nm.

[Table] Examples 16-22 0.15 mol% of CeO ₂ per 1 mol of CaCO ₃ and Table 4
Each was mixed with the stated amount of BaCO ₃ and kept at 1400°C for 5 hours, and the resulting oxide was mixed with H ₂ S atmosphere.
The mixture was kept at 1200° C. for 3 hours to obtain a phosphor called Ca _1-x Ba _x S:Ce. This structure was confirmed by X-ray diffraction. For comparison, a phosphor was obtained by performing the same treatment using a sample without BaCO ₃ mixed therein. The emission spectra of each of these phosphors are as shown in Figure 4, with a main emission peak at 520 nm,
It exhibited green luminescence with a shoulder at 580 nm.

[Table] Examples 23-30 0.1 mol% Eu ₂ O ₃ and 0.01 mol% CaCO ₃
CeO ₂ and BaCO ₃ in the amounts listed in Table 5 were mixed and calcined in air at 1300°C for 4 hours. The resulting oxide was sulfided at 1200°C for 2 hours in an H ₂ S atmosphere, and then PCl ₃ Ca _1-x Ba _x S: Eu, Ce, P, Cl was heated to 1200°C for 30 minutes in a mixed gas containing 5 mol% of Ar 0.5 atm and H ₂ S 0.5 atm. A light body was obtained. For comparison, a Ba-free phosphor was obtained without adding BaCO ₃ and firing in air for 5 hours. These phosphors are 2
Table 5 shows the results of measuring the relative energy efficiency (based on Ba-free) by irradiating the sample with an electron beam of 10 kV and 1 x 10 ^-6 A under ×10 ^-6 Torr vacuum.
Note that the emission spectrum of each sample was almost the same as that of the phosphor containing no P or Cl.

【table】

[Table] Examples 31 to 33 The same raw materials as in Example 27 were further added with 0.066 MgCO ₃
By adding mol%, 0.132 mol% and 0.264 mol% respectively and performing the same treatment, Ca _1-xy Ba _x Mg _y S:
We synthesized phosphors of Eu, Ce, P, and Cl. The relative energy efficiencies of these phosphors are shown in Table 6. When Ca lattice points are replaced by Ba ions as in the phosphor shown in Example 27, Ba
Since the ionic radius of the ion (1.43 Å) is larger than that of the Ca ion (1.06 Å), lattice distortion will occur due to substitution, but this will be compensated for by the Mg ion (0.78 Å), which has a smaller ionic radius than the Ca ion. That is. In other words, in Example 32, Mg ions were mixed in at a rate that calculated to exactly cancel out the lattice distortion caused by the mixing of Ba ions, and compared to those with a larger or smaller amount of Mg ions. and high energy efficiency.
If the amount of Mg is too high, the energy efficiency will be lower than if only Ba is added. The emission spectrum shows a single peak at 653 nm, and Mg,
The results were almost the same as those not containing P and Cl.

[Table] Example 34 SrCO ₃ with 0.1 mol% Eu ₂ O ₃ and 0.01 mol% CeO ₂
and 0.1 mol % of BaCO ₃ were mixed, the sulfiding temperature was set to 1000° C., and the concentration of PCl ₃ was set to 3 mol %, and the same treatment as in Examples 23 to 30 was carried out. The obtained phosphor was crushed and held again at 1050° C. for 2 hours in a mixed gas of Ar 0.5 atm and H ₂ S 0.5 atm. This phosphor is expressed by the formula Sr _1-x Ba _x S: Eu, Ce, P, Cl, and its relative energy efficiency is shown for comparison.
This was improved by 12.5% compared to that obtained by the same treatment without mixing BaCO ₃ . The emission spectrum showed a single peak at 612 nm, and was almost the same as that without P and Cl. Example 35 CeO ₂ without mixing Eu ₂ O ₃ in Example 34
Similar treatment was carried out with 0.15 mol% Sr _1-x Ba _x
S: Ce, P, Cl phosphors were obtained. For comparison, the relative energy efficiency of this phosphor is
This was an improvement of 22% compared to that obtained by the same treatment without mixing BaCO ₃ . Furthermore, the emission spectrum had a composite peak at 506 and 560 nm as shown in Figure 5, and was the same as that without Ba added. Example 36 In a mixture of 50 mol% _CaCO3 and 50 mol% _SrCO3
CeO ₂ 0.15 mol% and BaCO ₃ 0.1 mol% were mixed, kept at 1300°C in air for 4 hours, and the resulting oxide was heated with H ₂ S.
Sulfurized by keeping it at 1150℃ for 2 hours in an atmosphere of feces,
A phosphor of Ca _0.5-x/2 Sr _0.5-x/2 Ba _x S:Ce was obtained.
When this phosphor is irradiated with an electron beam of 10 kV and 1 × 10 ^-6 A in vacuum, an emission spectrum with a main peak at 514 nm and a sub-peak at 578 nm is obtained, and its relative energy efficiency is compared with that of Ba for comparison. This was a 14% improvement over the product made without the addition. Example 37 An aqueous solution containing 0.01% Eu ²⁺ was mixed with 6 g of CaCO ₃ so that the concentration of Eu ²⁺ in the mixture was 0.1 relative to CaCO ₃
It was made to be mol%. This mixture in the air
It was maintained at 1400°C for 4 hours to obtain 3.4g of Eu-added CaO calcined product. After crushing this oxide, divide it into two equal parts, fill one half into a quartz boat, and put it into a quartz reaction tube.
The temperature was 1150°C and H ₂ S gas was flowed at a rate of 100 c.c. per minute to sulfurize for 3 hours. This sample is designated as a. On the other hand, 1.7 g of the remaining fired material was sulfided in the same way, but only H ₂ S was flowed for the first 2 hours, Ar containing 10 ^-3 mol% of PCl ₃ was flowed for the next 30 minutes, and again for the last 30 minutes. A sulfide was obtained by flowing only H ₂ S (referred to as sample b). Apart from these, CaCO ₃ containing 0.1 mol% BaCO ₃
Mix Eu in the same _manner as _above using
A phosphor called Cl was obtained (referred to as sample c). sample b
The P concentration contained in sample c and sample c was 200 ppm, and the Ba concentration contained in sample c was 200 ppm. 5x each sample
The emission spectra obtained when excited with a 10 kV electron beam under a 10 ^-6 Torr vacuum are exactly the same with a single peak at 652 nm, but the relative energy efficiency is
Sample a is 1, sample b is 1.18, sample c is
It was 1.34. Examples 38-43 2g of _CaCO3 and 2.95g of _SrCO3 for carbonate
Mix 0.05 mol% _{of Eu2O3} and 0.01 mol% of _CeO2 ,
Furthermore, mixtures containing BaCO ₃ in amounts shown in Table 7 were prepared. For comparison, a sample without BaCO ₃ was also prepared. Each of these was fired in air at 1300°C for 4 hours, and then the fired products were filled into a quartz boat, each placed in a quartz reaction tube, heated to 1200°C, and H ₂ S gas was passed through. After 1.5 hours,
Ar containing 0.01 mol% of PCl ₃ was flowed at the same flow rate as H ₂ S gas for 30 minutes, and then only H ₂ S gas was flowed for 30 minutes. Thus
Ca _0.5-x/2 Sr _0.5-x/2 Ba _x S: Eu, Ce, P, Cl phosphors and a phosphor containing no Ba were obtained for comparison. The emission spectra of these phosphors upon electron beam excitation are exactly the same, with a single peak at 640 nm, but when comparing their emission intensities in terms of relative energy efficiency, Table 7 shows that Ba
A significant effect of the addition was observed.

[Table] In each of the above examples, carbonates such as Ca and Sr were used as raw materials, but sulfates, nitrates, sulfides, etc. can also be used. In addition, Eu and Ce are used as activators for these phosphors.
In addition, when Mn, Cu, Ag, etc. are used, Ba or
Sensitizing effects by Ba and Mg were observed. That is, examples are as follows. In addition, in Table 8, η _E indicates relative energy efficiency,
Each is the luminous energy efficiency based on the one without Ba.

【table】

【table】 [Brief explanation of the drawing]

FIG. 1, FIG. 2, FIG. 3, FIG. 4, and FIG. 5 are diagrams showing emission spectra of one embodiment of the present invention.

Claims (1)

[Claims] 1 General formula M _1-x Ba _x S; Ln (where M is Ca and
At least one element selected from the group consisting of Sr; Ln represents at least one element selected from the group consisting of Eu, Ce, Mn, Cu, and Ag; 5×
10 ^-5 x 0.01). 2. Claim 1 obtained by replacing a part of Ba in the phosphor represented by the above general formula with Mg.
The phosphor described in Section 1. 3. Phosphorus (P) is further added to the phosphor represented by the above general formula in the presence of a halogen element.
The phosphor according to claim 1 or 2, wherein 10,000 ppm is added.