JPS6144910B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a white light emitting phosphor and a cathode ray tube for display.

It is desirable to use high-resolution cathode ray tubes for computer terminal display devices, aircraft control system display devices, etc. that display detailed characters and graphics. A known method for improving the resolution of a cathode ray tube is to reduce the frame frequency of the cathode ray tube. In other words, the frame frequency of ordinary cathode ray tubes such as television cathode ray tubes is around 55Hz, but by lowering this frame frequency to around 30Hz, the signal frequency band can be expanded to about twice that of ordinary cathode ray tubes. Alternatively, the video frequency band can be selected to be approximately 1/2 that of a normal cathode ray tube, thereby increasing resolution. The reason why it is possible to increase the resolution of a cathode ray tube by reducing its frame frequency is that the video frequency band of the cathode ray tube drive circuit is determined by the product of the frame frequency and the signal frequency band. be.

The phosphor film of such a high-resolution cathode ray tube must be composed of a phosphor with long afterglow properties. This is because if the phosphor film of the cathode ray tube is composed of a phosphor with short afterglow properties, the phosphor film scans at a slow speed, causing flickering on the screen. In general, the phosphor that makes up the phosphor film of such a high-resolution cathode ray tube has an afterglow time (in this specification, the luminance after excitation stops is 10
% (meaning the "10% afterglow time") is several tens to hundreds of times longer than the short afterglow phosphor that makes up the phosphor film of an ordinary cathode ray tube. It needs to be long.

Traditionally, long-afterglow phosphors that can be used in high-resolution cathode ray tubes include manganese- and arsenic-activated zinc silicate green-emitting phosphors (Zn ₂ SiO ₄ :, Mn, As), and manganese-activated potassium fluoride.・Magnesium orange-emitting phosphor (KMgF ₃ :Mn), lead and manganese activated calcium silicate orange-emitting phosphor (CaSiO ₃ :Pb,
Mn), manganese-activated magnesium fluoride red-emitting phosphor (MgF ₂ :Mn), manganese-activated zinc/magnesium orthophosphate red-emitting phosphor [(Zn, Mg) ₃
(PO ₄ ) ₂ :Mn] etc. are known. However, not only white-emitting phosphors with long afterglow, but also blue-emitting phosphors and yellow-emitting phosphors with long afterglow are not known at all. The resulting white-emitting phosphor with long afterglow properties also does not exist. Another possible method for obtaining white light emission is to mix phosphors of red, green and blue light emitting components, but there is no long afterglow blue light emitting phosphor. In addition, since the afterglow characteristic curves of the long afterglow red light emitting phosphor and the long afterglow green light emitting phosphor are completely different, a color shift in the afterglow occurs. In addition, there are drawbacks such as color unevenness that tends to occur when phosphors of multiple components with different emission colors are mixed. Obtaining a body is not very desirable.

As mentioned above, long-afterglow white-emitting phosphors have not been known at all, and therefore, displays that have long-afterglow white-emitting phosphors in their phosphor films are used for displays capable of high-resolution display. Black and white television cathode ray tubes also did not exist.

SUMMARY OF THE INVENTION An object of the present invention is to provide a white-emitting phosphor with long afterglow properties and good luminescent properties, and a cathode ray tube for black-and-white television for display having this phosphor in a fluorescent film.

In order to achieve the above object, the inventors of the present invention can produce white light emission using a small number of luminescent component phosphors, and each luminescent component phosphor has sufficient afterglow. Various studies have been carried out in order to provide a long-afterglow white-emitting phosphor with almost the same characteristics and a black-and-white television cathode ray tube for display using this phosphor as a fluorescent film. the result,
We have discovered a novel long-afterglow blue-emitting phosphor and a long-afterglow yellow-emitting phosphor, and have thus developed a long-afterglow blue-emitting component phosphor and a long-afterglow yellow-emitting component phosphor. A long-afterglow white-emitting phosphor consisting of a mixed phosphor of two components, and a black and white television cathode ray tube (hereinafter simply referred to as cathode ray tube) for display use, which uses this phosphor as a fluorescent film. The present invention was completed based on the discovery that the present invention can be provided.

The white light-emitting phosphor of the present invention has a compositional formula of ZnS:aAg:bM〓:cM〓:dX (where M〓 is at least one of copper and gold, M〓 is at least one of gallium and indium, X is at least one of chlorine, bromine, iodine, fluorine and aluminum,
a, b, c and d are each 5×10 ^-6 ≦a≦
10 ^-3 , 0≦b≦2×10 ⁻⁴ , 10 ⁻⁸ ≦c≦10 ⁻³ and 5×10 ⁻⁸ ≦d≦5×10 ⁻⁴ , and the same applies hereinafter. ), and the composition formula is (Zn _1-x , Cd _x )S:eM〓′:fM〓′:gX′ (where M〓′ is copper and gold. M〓′ is at least one of gallium and indium, X′ is at least one of chlorine, bromine, iodine, fluorine, and aluminum, and x, e, f, and g are each 0≦ x≦
0.3, ^{10 -6} ≦e≦10 ^-2 , 5×10 ^-8 ≦f≦5×10 ^-3 and 10 ^-8 ≦g≦10 ^-3 , which are numbers that satisfy the following conditions.
The same shall apply hereinafter. ) A long-afterglow yellow-emitting phosphor (strictly speaking, it is a yellow-green to yellow-emitting phosphor, but in the present invention it is abbreviated as a yellow-emitting phosphor, and the same shall apply hereinafter).
A mixed phosphor comprising the following, characterized in that a weight ratio of the long afterglow yellow emitting phosphor to the long afterglow blue emitting phosphor is in the range of 0.34 to 5.00.

The cathode ray tube of the present invention has a compositional formula of ZnS:aAg:bM〓:cM〓:dX (However, the definitions of M〓, M〓, X, a, b, c and d are the same as above). The long-afterglow blue-emitting phosphor represented by the formula is (Zn _1-x , Cd _x )S:eM〓′:fM〓′:gX′ (However, M〓′, M〓′, , x, e, f and g
The definition of is the same as above. ), wherein the weight ratio of the long afterglow yellow emitting phosphor to the long afterglow blue emitting phosphor is 0.34. It is characterized by having a phosphor film made of a white-emitting phosphor in the range of ~5.00 on the face plate.

The white light emitting phosphor of the present invention can emit any white light depending on the mixing ratio, and the afterglow characteristics of the long afterglow blue light emitting phosphor and the long afterglow yellow light emitting phosphor can be almost the same. Therefore, it can emit white light without color shift for display purposes.

In addition, in the cathode ray tube of the present invention, it is possible to almost eliminate the difference in particle size distribution between the long afterglow blue emitting phosphor and the long afterglow yellow emitting phosphor, so there is no color unevenness. A uniform fluorescent surface can be formed. Furthermore, since it is necessary to freely adjust the afterglow time, it is possible to use a frame frequency according to necessity.

The long afterglow blue emitting phosphor and the long afterglow yellow emitting phosphor used in the present invention have a cubic or hexagonal crystal system as their main crystal phase depending on the composition and firing temperature during production. , a phosphor with a cubic crystal system as the main crystal phase exhibits higher luminance than a phosphor with a hexagonal system as the main crystal phase, and also has higher emission brightness and emission color purity. Within the range of activation amounts of the co-activators (Ga, In) that provide the desired brightness, the former has a longer afterglow time than the latter. From this point of view, among the phosphors of the present invention, phosphors having a cubic crystal system as a main crystal phase are more preferable as phosphors for cathode ray tubes than phosphors having a hexagonal system as a main crystal phase. It is. However, the long-afterglow yellow-emitting phosphor containing cadmium (Cd) in its matrix has a content of approximately 5 mol%.
When the crystal size exceeds that level, the main crystal is generally hexagonal.

Note that all values of afterglow time described in this specification are values when the current density of the stimulating electron beam is 0.4 μA/cm ² .

It should be noted here that the phosphor used in the present invention has a characteristic that conventional long-afterglow phosphors do not have, in that the afterglow time varies greatly depending on the current density of the stimulating electron beam. The trend is that as the current density decreases, the afterglow time increases.

The present invention will be explained in detail below.

The long afterglow blue emitting phosphor used in the present invention is
(i) Zinc sulfide raw powder (base raw material) or zinc sulfide raw powder containing a large amount of sulfur during refining (base and sulfur raw material); (ii) Silver compound (activator raw material); (iii)
at least one compound of gallium or indium (first coactivator raw material); (iv) at least one compound of copper or gold (second coactivator raw material); and (v) alkali metal and alkaline earth Weigh out the required amount of at least one metal halide compound or aluminum compound (third coactivator raw material) (if b=0 in the above compositional formula, the second coactivator raw material (iv ) can be omitted), the resulting phosphor raw material mixture is fired in a sulfur atmosphere at a temperature of 600 to 1200°C for 0.5 to 7 hours,
It can be manufactured by washing the obtained fired product with water, drying it, and passing it through a sieve (Japanese Patent Application Laid-Open No. 1983-1999)
No. 79814, No. 58-83084, No. 58-83085, No. 58-
115024, 58-120521, 58-129083, etc.)

The long-afterglow yellow-emitting phosphor used in the present invention is made of zinc sulfide or zinc sulfide cadmium raw powder (base raw material), or zinc sulfide or zinc sulfide cadmium raw powder containing a large amount of sulfur during refining. (Material and sulfur raw material); () At least one compound of gold or copper (activator raw material);
() At least one compound of gallium or indium (first coactivator raw material); () At least one type of halogen compound of alkali metal and alkaline earth metal, or aluminum compound (second coactivator raw material) ) as a raw material for the phosphor, and can be produced in the same manner as the above-mentioned long afterglow blue-emitting phosphor (see JP-A-58-142970).

The long-afterglow blue-emitting phosphor thus obtained has a compositional formula of ZnS:aAg, bM〓, cM〓, dX. , including cases containing 10 ^-7 to 8 x 10 ^-3 sulfur). The luminescent color of this blue-emitting phosphor changes mainly depending on the activation amount of Ag (a value), the selected type of M and its activation amount (b value), and its afterglow characteristics (afterglow time, etc.) ) is mainly M〓
The selected type and its activation amount (c value), and
It is determined by the selected type and its activation amount (d value). The above a and b values are selected within the ranges of 5×10 ⁻⁶ ≦a≦10 ⁻³ and 0≦b≦2×10 ⁻⁴ , respectively, in order to cause light to emit in the blue light emitting region. Note that the above value is 5×10 ^-6 ≦a≦ from the point of view of color purity and brightness.
The range of 5×10 ⁻⁴ and 0≦b≦10 ⁻⁵ is preferable. In addition, the above c value and d value are 10 ^-8 ≦c≦10 ^-3 and 5×10 ^-8 ≦d≦5×, respectively, from the afterglow characteristics.
The range 10 ^-4 is chosen. Note that the above values are 10 ^-7 ≦c≦10 ^-4 and 10 ^-7 in terms of afterglow time and brightness.
A range of ≦d≦10 ⁻⁴ is preferable.

On the other hand, the long afterglow yellow emitting phosphor obtained as described above has a compositional formula of (Zn _1-x , Cd _x )S:
eM〓′, fM〓′, gX′ (in the present invention, 10 ⁻⁷
Cases containing up to 8×10 ^-3 sulfur are also included. ). The emission color of this yellow-emitting phosphor is mainly determined by the selected type of M〓' and its activation amount (e value) and the parent material.
It changes depending on the amount of substitution (x value) in which Zn is replaced with Cd, and its afterglow characteristics (afterglow time, etc.) are mainly determined by M〓
′ selected type and its activation amount (f value)
Selected type of X′ and its activation amount (g value)
Depends on. The e and x values are selected within the ranges of 10 ^-6 ≦e≦10 ^-2 and 0≦x≦0.3, respectively, in order to cause light to emit in the yellow light emitting region. In addition, the above value is 10 ^-5 ≦e≦5× from the point of view of color purity and brightness.
10 ^-3 and 0≦x≦0.2 are more preferred. Furthermore, the above f value and g value are 5×10 ^-8 ≦f≦5×10 ^-3 and 10 ^-8 ≦g≦ from the afterglow characteristics, respectively.
The range 10 ^-3 is chosen. Note that the above values are 10 ^-7 ≦f≦10 ^-4 and 5× from the point of afterglow time and brightness.
More preferably, the range is 10 ^-8 ≦g≦5×10 ^-4 .

The white-emitting phosphor of the present invention has a chromaticity point of A in the CIE color system.
(x=0.23, y=0.23), B(x=0.25, y=
0.35), C (x=0.35, y=0.40), D (x=
The weight ratio of the long afterglow yellow light emitting phosphor to the long afterglow blue light emitting phosphor is set such that a white light emitting region surrounded by 0.35, y=0.30) emits light.
It is obtained by mixing both in the range of 0.34 to 5.00. The above mixing ratio is based on the CIE color system chromaticity point A' (x=0.25, y=
0.25), B′ (x=0.25, y=0.30), C′(x=
0.32, y=0.37) and D' (x=0.32, y=0.30), it is more preferable to mix at a weight ratio of 0.5 to 4.0.

The structure of the cathode ray tube of the present invention, as shown in FIG. 1, is almost the same as the conventional cathode ray tube for black and white television, except for the fluorescent film. That is, the cathode ray tube of the present invention has one electron gun 3 in the funnel 1 neck part 2.
A fluorescent film 5 is formed on the entire surface of a face plate 4 facing the electron gun 3. Generally, an aluminum vapor-deposited film 6 is provided on the back side of the fluorescent film 5 to prevent charge-up during excitation. The cathode ray tube constructed in this manner is characterized in that the phosphor film is made of the white-emitting phosphor described above. The fluorescent film is formed by a precipitation coating method, etc., which is generally employed as a method for forming a fluorescent film for cathode ray tubes for black and white television. The amount of phosphor in the phosphor film is suitably in the range of 1.0 mg to 10 mg per 1 cm ² from the viewpoint of emission brightness, cathode ray beam diameter, current density, accelerating voltage, etc., and more preferably 1.0 mg to 10 mg per 1 cm ^{2 .}
It ranges from 2.5mg to 7mg per serving. In the present invention, the afterglow time of the phosphor is preferably selected from 5 to 150 milliseconds in terms of brightness and image display.

Further, in the present invention, the beam diameter of the cathode rays emitted from the electron gun 3 when it hits the fluorescent film 5 is 0.05~
Preferably it is in the range of 0.4 mm and the frame frequency used is preferably between 20 and 50 Hz.

Figure 2 shows the luminescence of the white-emitting phosphor of the present invention and its component phosphors, a long-afterglow blue-emitting phosphor and a long-afterglow yellow-emitting phosphor, under electron beam excitation. Chromaticity points are shown on CIE color system chromaticity coordinates.

Chromaticity point B ₁ (x=0.147, y=0.056), Y ₁ (x=
0.369, y=0.568) and Y ₂ (x=0.427, y=
0.548) are long afterglow blue emitting phosphors.
ZnS: 10 ^-4 Ag: 1.5×10 ^-5 Ga: 10 ^-6 Cl, long afterglow yellow emitting phosphor ZnS: 1.4×10 ^-3 Au.10 ^-4 Ga: 6×
10 ^-4 Al and long afterglow yellow emitting phosphor
Zn _0.89 Cd _0.11 S: 1.2×10 ^-4 Cu: 1.5×10 ^-5 _{Ga :} 3×
10 ^-4 for Al, with chromaticity points W ₁ and W ₂
are long-afterglow blue-emitting phosphor ZnS:
10 ^-4 Ag: 1.5 x 10 ^-5 Ga: 10 ^-6 Cl and long afterglow yellow emitting phosphor ZnS: 1.4 x 10 ^-3 Au: 10 ^-4 Ga: 6 x
White-emitting phosphor and long-afterglow blue-emitting phosphor of the present invention mixed with 10 ^-4 Al at a weight ratio of 3:7
ZnS: ^10-4 : 1.5× ^10-5 Ga: ^10-6 Cl and long afterglow yellow _emitting phosphor Zn _0.89 Cd _0.11 S: _1.2 × ^10-4 Cu: 1.5×
This is for the white light-emitting phosphor of the present invention in which 10 ^-5 Ga:3×10 ^-4 Al is mixed in a weight ratio of 3:7.

FIG. 3 is a graph showing the emission spectrum and afterglow emission spectrum of a white light emitting phosphor of the present invention giving a chromaticity point _W2 . Curve a in FIG. 3 is the emission spectrum during cathode ray excitation, curve b is the emission spectrum 10 milliseconds after the cathode ray excitation is stopped, and curve c is the emission spectrum 20 milliseconds after the cathode ray excitation is stopped. As is clear from FIGS. 2 and 3, the white-emitting phosphor of the present invention and the cathode ray tube using this phosphor as a phosphor film emit white light with good color purity, and its afterglow color Since this method causes almost no color shift, it is possible to provide a high-definition cathode ray tube.

Incidentally, in the phosphor and cathode ray tube of the present invention, a pigment can be attached to or mixed with the phosphor in order to improve contrast. As the pigment to be deposited, a pigment or a black pigment having a body color that is almost the same as the emission color of the phosphor is used. In the present invention, it is particularly preferable to use a black pigment such as iron oxide or tungsten, and it is recommended that the amount used is 0.5 to 40 parts by weight per 100 parts by weight of the phosphor.

Note that in the phosphor used in the present invention, at least a portion of the first co-activator gallium or indium may be replaced with scandium. Further, the phosphor used in the present invention may be further activated with an activator such as divalent europium, bismuth, or antimony.

Furthermore, the white-emitting phosphor of the present invention can be subjected to any of the surface treatments and particle size selections used in conventionally known sulfide phosphors and white-emitting phosphors. In addition to the above-mentioned cathode ray tube, it is also used as a fluorescent surface in other display tubes, such as fluorescent display tubes using low-speed electron beam excitation.

Next, the present invention will be explained with reference to Examples.

Example 1 Composition formula is ZnS: 10 ^-4 Ag: 1.5×10 ^-5 Ga: 10 ^-6 Cl
The afterglow time is 35 milliseconds, and the luminescent color is second
The blue-emitting phosphor shown in figure _B1 and its compositional formula are
Zn _0.89 Cd _0.11 S: 1.2×10 ^-4 Cu: 1.5×10 ^-5 _{Ga :} 3×
10 ^-4 Yellow luminescent phosphors expressed by Al, with an afterglow time of 35 milliseconds, and an emission color of point _Y2 in Figure 2 were weighed at a weight ratio of 3:7 and mixed uniformly. A white-emitting phosphor was obtained. This mixed phosphor was uniformly coated onto a face plate at a coating weight of 4 mg/cm ² by a precipitation coating method to form a phosphor film, and then the present invention was applied according to a general black-and-white television cathode ray tube manufacturing method. manufactured cathode ray tubes. The emission color of this cathode ray tube is shown in Fig. 2 W ₂ (x = 0.302, y = 0.333), and the emission spectrum is shown in Fig. 3, curve a.
After milliseconds, curve b shows afterglow, and after 20 milliseconds, curve c shows afterglow. Due to this good afterglow characteristic and no color shift, a high-resolution cathode ray tube was obtained.

Example 2 The composition formula is ZnS: 10 ^-4 Ag: 10 ^-5 Ga: 10 ^-6 Cl, the afterglow time is 30 milliseconds, and the luminescent color is as shown in the second figure.
A blue-emitting phosphor that is B ₁ and a composition formula of ZnS: 1.4×
10 ^-3 Au: 10 ^-4 Ga: 6 x 10 ^-4 Al, yellow luminescent phosphors with an afterglow time of 27 milliseconds and an emission color of point Y ₁ in Figure 2, respectively, in weight ratio. They were weighed so that the ratio was 3:7 and mixed uniformly to obtain a white light-emitting phosphor. A cathode ray tube was manufactured using this phosphor in the same manner as in Example 1. The emission color of this cathode ray tube is shown in Figure 2.
A cathode ray tube of the present invention was obtained which exhibited good white light emission and afterglow characteristics as shown by W ₁ (x=0.270, y=0.350).

Example 3 A blue-emitting phosphor with a composition formula of ZnS:10 ^-4 Ag:2×10 ^-5 In:10 ^-6 Cl and an afterglow time of 20 milliseconds and a composition formula of ZnS:1.4. ×10 ^-3 Au: 10 ^-4 In: 6
Yellow-emitting phosphors expressed by ×10 ^-4 Al and having an afterglow time of 20 milliseconds were weighed at a weight ratio of 3:7, and mixed uniformly to obtain a white-emitting phosphor. Ta. A cathode ray tube was manufactured using this phosphor in the same manner as in Example 1. The emission color of this cathode ray tube is (x=
The cathode ray tube of the present invention was obtained, which exhibits good white light emission and afterglow characteristics expressed as 0.27, y=0.35).

Example 4 A cathode ray tube was obtained in exactly the same manner as in Example 1 except that a blue-emitting phosphor and a yellow-emitting phosphor containing 10 ^-4 % by weight of sulfur based on the phosphor matrix were used. Showing the same emission color and afterglow characteristics as Example 1,
Furthermore, white brightness was improved by 6%.

Example 5 Composition formula is ZnS: 10 ^-4 Ag: 1.4×10 ^-5 Ga: 2×
A blue-emitting _phosphor represented by 10 ^-5 Al, with an afterglow time _{of 35 milliseconds and an emission color of point B1 in the second figure, and a compositional formula of (Zn 0.8 Cd 0.2 )} S: 1.0 ×10 ^-4 Cu: 1.5 × 10 ^-5 Ga: 5
×10 ^-4 Br, an afterglow time of 35 milliseconds, and a luminescent color of point _Y1 in Figure 2 were weighed to give a weight ratio of 3:7, and evenly distributed. A white emitting phosphor was obtained by mixing. This mixed phosphor was uniformly coated onto a face plate at a coating weight of 4 mg/cm ² by a precipitation coating method to form a phosphor film, and then the present invention was applied according to a general black-and-white television cathode ray tube manufacturing method. manufactured cathode ray tubes. The emission color of this cathode ray tube is shown in Figure 2 W ₁ (x=0.270, y=0.350)
The emission spectrum is shown in curve a in Figure 3, and the emission spectrum is shown in curve a in Figure 3.
Afterglow after 10 milliseconds was shown by curve b, and after 20 milliseconds by curve c, and this good afterglow characteristic without color shift made it possible to obtain a high-resolution cathode ray tube.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a black-and-white television cathode ray tube for displays according to the present invention, and FIG. 2 is a CIE color scheme showing the luminescent color of the phosphor used in the present invention and the black-and-white television cathode ray tube for displays according to the present invention. FIG. 3 is a graph showing the emission spectrum and afterglow emission spectrum of the phosphor of the present invention. DESCRIPTION OF SYMBOLS 1... Funnel, 2... Network part, 3... Electron gun, 4... Face plate, 5... Fluorescent film, 6
...Aluminum vapor deposited film.

Claims (1)

[Claims] 1. The compositional formula is ZnS:aAg;bM〓:cM〓:dX (However, M〓 is at least one of copper and gold, M〓 is at least one of gallium and indium, and X is At least one of chlorine, bromine, iodine, fluorine and aluminum,
a, b, c and d are each 5×10 ^-6 ≦a≦
The numbers satisfy the following conditions: 10 ^-3 , 0≦b≦2×10 ⁻⁴ , 10 ⁻⁸ ≦c≦10 ⁻³ and 5×10 ⁻⁸ ≦d≦5×10 ⁻⁴ . ), and the composition formula is (Zn _1-x Cd _x )S:eM〓′:fM〓′:gX′ (where M〓′ is at least copper and gold. On the other hand, M〓' is at least one of gallium and indium, X' is at least one of chlorine, bromine, iodine, fluorine, and aluminum, and x, e, f, and g are each 0≦x ≦
The numbers satisfy the following conditions: 0.3, ^{10 -6} ≦e≦10 ^-2 , 5×10 ^-8 ≦f≦5×10 ^-3 and 10 ^-8 ≦g≦10 ^-3 . ), wherein the weight ratio of the long afterglow yellow emitting phosphor to the long afterglow blue emitting phosphor is 0.34. A white-emitting phosphor in the range of ~5.00. 2. The white light emitting phosphor according to claim 1, wherein the long afterglow blue light emitting phosphor and the long afterglow yellow light emitting phosphor have a cubic crystal system as a main crystal. . 3. The long afterglow blue light emitting phosphor has a cubic crystal system as its main crystal, and the long afterglow yellow light emitting phosphor has 0.05≦
2. The white light emitting phosphor according to claim 1, wherein x≦0.3 and the main crystal is hexagonal system. 4. The white light emitting phosphor according to claim 1, 2 or 3, wherein at least one of M〓 and M〓' is gallium. 5 The composition formula is ZnS:aAg:bM〓:cM〓:dX (However, M〓 is at least one of copper and gold, M〓 is at least one of gallium and indium, and X is chlorine, bromine, iodine, at least one of fluorine and aluminum,
a, b, c and d are each 5×10 ^-6 ≦a≦
The numbers satisfy the following conditions: 10 ^-3 , 0≦b≦2×10 ⁻⁴ , 10 ⁻⁸ ≦c≦10 ⁻³ and 5×10 ⁻⁸ ≦d≦5×10 ⁻⁴ . ), and the composition formula is (Zn _1-x , Cd _x )S:eM〓′:fM〓′:gX′ (where M〓′ is copper and gold. M〓′ is at least one of gallium and indium, X′ is at least one of salt, bromine, iodine, fluorine, and aluminum, and x, e, f, and g are each 0≦ x≦
The numbers satisfy the following conditions: 0.3, ^{10 -6} ≦e≦10 ^-2 , 5×10 ^-8 ≦f≦5×10 ^-3 and 10 ^-8 ≦g≦10 ^-3 . ), wherein the weight ratio of the long afterglow yellow emitting phosphor to the long afterglow blue emitting phosphor is 0.34. 1. A cathode ray tube for a display, characterized in that it has a phosphor film made of a white-emitting phosphor in the range of 5.00 to 5.00 on a face plate.