KR910004677B1 - Orange color fluorescent substance - Google Patents

Abstract

An orange phosphor is prepared with CaCO3, MgSO4, MnSO4, Na2CO3 and NH4Cl, expressed by Ca1-xMgxS: Mn, A (0.01<= x < 0.05, A is Na or a Hallide element) in general formula. The concentration of Mn is 0.1-2.0 mol%. In the range of 0.01<= x < 0.05, obtaining Mn-orange phorsphor which is stable in crystal structure, high efficient radiation in cathod ray stimalation. Adding alkali metal and hallide element elevate the emitting efficiency. The orange phosphor is useful for cathode ray tube.

Description

Orange phosphor

The figure is a graph showing the change of the CIE color coordinate X value according to the change of manganese (Mn) content.

The present invention relates to a sulfide phosphor, and more particularly, to an Mn-activated isochromescent sulfide phosphor suitable for a cathode ray tube for display.

Recently, the demand for display cathode ray tubes is increasing rapidly in the field of information society, various information processing terminals, numerical control equipment, computer design, education, and office rationalization. Most of the cathode ray tubes for displays currently used are displayed in green, paper white, and yellow orange color. However, green color gives a lot of fatigue to eyes when viewed for a long time, and orange and white have recently been preferred.

Here, Table 1 shows the types of phosphors used for orange and orange light emission and their afterglow characteristics.

TABLE 1

Orange and orange phosphor

As shown in Table 1, since 3CD ₃ (PO ₄ ) ₂ · CdCl ₂ : Mn, which is most commonly used as an orange phosphor for displays, contains cadmium (Cd), it requires a strict pollution prevention system for waste disposal. In practical use, the phosphor is mixed with Zn ₂ Sio ₄ : Mn, As and Zn ₃ (PO ₄ ) ₂ : Mn, the emission color changes during decay after excitation and color saturation It is low and has the disadvantage that the formed fluorescent film becomes nonuniform.

In general, phosphors based on CaS can vary the emission color to visible and infrared regions according to the type of activator, and can also stabilize the matrix to control the emission color. For example, Japanese Patent Application Laid-Open No. 57-128772 The Cu-activated red phosphor at Ca.T-xMgxS (0.05≤x≤0.95) showed a peak of 414-441 nm, while the Eu-activated red phosphor had a peak of 625-655 nm. Although it is possible to control a wide range of colors, however, it is pointed out that the composition of x <0.05 or x> 0.95 has a problem in reproducibility because the mother mixed crystals are unstable in crystal structure and have poor controllability.

On the other hand, according to Japanese Patent Publication No. 62-23032, the stability and reproducibility of Cu-activated blue phosphor and Eu-activated red phosphor are sufficient even in the range of x <0.05, and it is excellent in practicality as cathode ray-stimulated phosphor.

However, according to the present inventors' experiments, the Mn activating isophore is obtained separately from the above example in the 0.011 <x0.05 composition range, which is crystallographically stable and isochromatically emitted at high efficiency with respect to cathode stimulation. By adding alkali metal and halide element, it was confirmed that the luminous efficiency is more always.

Ca _1- xMgxS according to the present invention; Since Mn, A (0.01'x <0.05, A is Na or halide element) isoluminescent phosphors do not contain Cd, there is no need to consider the pollution problem, and since it is a single composition, the emission color change of the extinction period appearing in the mixed phosphor or The practically excellent fluorescent substance which prevented the nonuniform lighting of a fluorescent film fundamentally was obtained and led to this invention.

Thus, the present invention will be described in more detail with reference to Examples.

EXAMPLE

CaCO ₃ , MgSO ₄ , MnSo ₄ , Na ₂ CO ₃ , NH ₄ CI are used as raw materials. First, 1 mol of CaCO ₃ powder is added to 2000 ml of pure water, and stirred with a stirrer to disperse evenly, followed by MgSO ₄ . A solution of 0.5 mol of 4H ₂ O in 100 ml is added to the CaCO ₃ dispersion.

Subsequently, when NH ₄ OH is added dropwise with a pipet and precipitated, brown precipitates are gradually formed. If NH ₄ OH is added continuously, the color does not change any more (the amount of NH ₄ Oh added until this time is about 5- The precipitate was filtered and separated by water, and the brown precipitate was dried for 12 hours using a dryer at 110 ° C., and then separated into 400 mesh sieves to obtain a highly dispersible powder.

Next, dry mix MgSO₄1.5mol%, NaCO₃2mol%, NH₄Cl 0.5mol% and 10wt% with a ball mill. At this time, add the raw powder obtained from the brown precipitate, mix for 30 minutes, and then remove the powder obtained by # 100 mesh sieve separation. Placed in an aluminum crucible and covered with a lid, it was calcined at 1200 DEG C for 4 hours by ordinary heating to make the present invention Ca0.986Mg0.014S: Mn (0.8 mol%), Cl (2.0 mol%).

In this case, the change in the CIE color coordinate X value of the phosphor obtained by changing the content of the activator Mn from 0.1 mol% to 2.0 mol% is shown in the accompanying drawings.

As can be seen from the figure, it can be seen that as the Mn content increases, the CIE color coordinate X value increases within a limited range. As the color coordinate X increases, the emission color shifts from orange to orange, and the luminance decreases when considering luminous efficiency. . Therefore, in order to obtain the optimum luminance, it is preferable to add Mn in the range of 0.8 mol%-1.6 mol%.

Ca _0.97 Mg _0.03 S: Mn (0.8mol%), Cl (2.0mol%) isochromescent phosphor with mother composition ratio x = 0.03 has 3Cd (Po0) ₅ CdCl ₂ : Mn in CIE color coordinate (X = 0.555, Y = 0.455) The brightness is approximately 10% higher, and the orange light emitting phosphor according to the present invention does not contain Cd, and thus has no advantage of causing pollution.

However, the property decomposed by moisture, which is the biggest practical limitation in alkaline earth sulfide phosphors, also shows excellent water resistance compared to a single CaS matrix, which does not cause practical problems. Especially, it is known as a fluorescent film forming method of cathode ray tubes for displays. Even when the fluorescent film was formed by gravity sedimentation, the sulfide phosphor according to the present invention showed a uniform film state, and it was confirmed that the cathode ray emitted satisfactorily here.

In addition, in the phosphors in which two or more phosphors are mixed, the emission color is generally changed due to the difference in the afterglow time of each component phosphor during quenching after excitation. Since the sulfide phosphors according to the present invention have a single composition, There is an advantage that the emission color does not change in the process.

Claims (2)

An orange phosphor represented by the general formula Ca _1- x MgxS: Mn, A, wherein A is at least one element of Na or a halide element, and the x range is 0.011 <x <0.05. 2. The isophosphor according to claim 1, wherein the concentration of Mn is in the range of 0.1-2.0 mol%.

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