JPS6234079B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a luminescent composition that emits blue light and a low-speed electron beam-excited fluorescent display tube using the luminescent composition as a fluorescent film. More specifically, the present invention provides a luminescent composition prepared by mixing an appropriate amount of a complex oxide of cadmium and tin with one or more specific blue-emitting phosphors, and a luminescent film using this luminescent composition. The present invention relates to a low-speed electron beam excited fluorescent display tube.

As is well known, a low-speed electron beam-excited fluorescent display tube (hereinafter abbreviated as a "fluorescent display tube") has an anode plate having a fluorescent film on one side, and a cathode facing the fluorescent film. The device essentially has a structure in which it is sealed in a vacuum container, and the fluorescent film on the anode plate is excited by the low-speed electron beam emitted from the cathode, causing it to emit light. 1 and 2 are schematic diagrams of typical examples of fluorescent display tubes, with FIG. 1 showing a diode tube and FIG. 2 a triode tube. 1st
As shown in the drawings and FIG. 2, a fluorescent film 12 is provided on one side of an anode plate 11 made of an aluminum plate or the like. Anode plate 11 is supported by ceramic substrate 13. Anode plate 1
A cathode 14 is provided opposite the fluorescent film 12 provided on one side of the fluorescent film 1, and the fluorescent film 12 is excited by the low-speed electron beam emitted from the cathode 14 to emit light. In particular, in the triode shown in Fig. 2, the cathode 14
A grid electrode 15 is provided in the gap between the cathode 14 and the fluorescent film 12 for controlling or diffusing the low-speed electron beam emitted by the cathode 14. Although one cathode 14 is used in the fluorescent display tube shown in FIGS. 1 and 2, two or more cathodes may be provided when the fluorescent film 12 has a large area. There is no particular limit to the number. Fluorescent film 1 on one side
2, a ceramic substrate 13 and a cathode 14 (FIG. 1), or a cathode plate 11 having a fluorescent film 12 on one side, a ceramic substrate 13, a cathode 14 and a grid electrode 15 (a second
(Fig.) is sealed in a transparent container 16 made of glass or the like, and the interior 17 thereof is maintained at a high vacuum of 10 ^-5 to ^{10 -9} Torr.

Conventionally, indium oxide (In ₂ O ₃ ) and silver-activated zinc sulfide phosphors (ZnS:Ag) have been used as phosphors that emit blue light by slow electron beam excitation at accelerating voltages of 1 KV or less, particularly 100 V or less. (Japanese Patent Publication No. 52-23911), and a luminescent composition obtained by mixing appropriate amounts of zinc oxide (ZnO) and ZnS:Ag phosphor (Japanese Patent Publication No. 53-25719). No.) is known. ZnS, a component of these luminescent compositions:
Ag phosphor exhibits almost no light emission under slow electron beam excitation at accelerating voltages of 1KV or less, especially 100V or less, but when an appropriate amount of ZnS:Ag phosphor is
The above two types of luminescent compositions obtained by adding and mixing In ₂ O ₃ or ZnO have an acceleration voltage of
It emits blue light with high brightness (approximately 1,000 times that of ZnS:Ag phosphor alone at 100V) under slow electron beam excitation of 1KV or less, especially 100V or less. Of these two types of blue light-emitting compositions, the light-emitting composition using In ₂ O ₃ exhibits higher luminance than the light-emitting composition using ZnO, but since In ₂ O ₃ is extremely expensive, Practical use is not desirable from an economic point of view. On the other hand, the luminescent composition using ZnO is significantly cheaper than the luminescent composition using In ₂ O ₃ , but its luminance is low.
It is lower than the luminescent composition using In ₂ O ₃ and is not necessarily sufficient for practical use.

The present applicant previously filed a patent application for a blue light-emitting composition made by mixing appropriate amounts of tin oxide (SnO ₂ ) and a ZnS:Ag phosphor (Japanese Patent Application Laid-Open No. 5887-1987). Similar to the luminescent composition using ZnO, this luminescent composition using SnO ₂ uses In ₂ O ₃ and is cheaper than the luminescent composition, and its luminescence brightness under slow electron beam excitation is lower than that of In ₂ O 3 . Although it is lower than the luminescent composition using O ₃ , it is higher than the luminescent composition using ZnO. As described above, although the luminescent composition using SnO ₂ disclosed in JP-A-54-5887 has lower luminance than the luminescent composition using In ₂ O ₃ , it is more economical than the luminescent composition using In 2 O 3. Because of this advantage, it is desired to improve the luminance of luminescent compositions using SnO ₂ to approach the luminance of luminescent compositions using In ₂ O ₃ .

The present invention was made under the above-mentioned circumstances, and improves the blue light-emitting composition disclosed in the above-mentioned Japanese Patent Application Laid-open No. 54-5887, and improves the blue light emitting composition disclosed in the above-mentioned Japanese Patent Application Laid-open No. 54-5887.
The object of the present invention is to provide a blue light-emitting composition that emits light with higher brightness than this blue light-emitting composition under slow electron beam excitation of 100 V or less.

The present invention also provides a fluorescent display tube whose fluorescent film is the blue light emitting composition of the present invention obtained by improving the blue light emitting composition disclosed in JP-A-54-5887. This is the purpose.

In order to achieve the above object, the present inventors have
Further research was carried out on the blue-emitting composition disclosed in No. 5887. As a result, one of the constituents of the blue-emitting composition disclosed in JP-A No. 54-5887.
Cadmium oxide (CdO) instead of SnO ₂ and this
When using a composite oxide of cadmium and tin (hereinafter referred to as "cadmium/tin composite oxide") obtained by mixing an appropriate amount _of SnO ₂ and firing, the It was discovered that the luminescence brightness was improved under slow electron beam excitation, and this effect was further enhanced when the other component was ZnS:
In addition to Ag phosphors, blue-emitting phosphors include silver- and aluminum-activated zinc sulfide phosphors (ZnS: Ag, Al), self-activated calcium tungstate phosphors (CaWO ₄ ), and cerium-activated phosphors. Active yttrium silicate phosphor (Y ₂ SiO ₅ :Ce), europium-activated barium/magnesium aluminate phosphor [(Ba, Mg)O.6Al ₂ O ₃ :Eu ²⁺ ], cerium-activated calcium silicate. Magnesium phosphor (Ca ₂ MgSiO ₅ :Ce), silver activated zinc sulfur selenide phosphor [Zn(S,Se):Ag], silver and aluminum activated zinc sulfur selenide phosphor [Zn(S) , Se):
Ag, Al], cerium-activated strontium-gallium sulfide phosphor (SrGa ₂ S ₄ :Ce), titanium-activated calcium-magnesium silicate phosphor [(Ca,
Mg) ₂ SiO ₄ :Ti], europium-activated strontium barium phosphate phosphor [(Sr, Ba) ₃ (PO ₄ ) ₂ :
Eu ²⁺ ] and a europium-activated calcium chloroborate phosphor (Ca ₂ B ₅ O ₉ Cl: Eu ²⁺ ); Accelerating voltage is 1KV or less by mixing appropriate amounts of one or more types of
In particular, the present inventors have found that it is possible to obtain a blue-emitting composition that emits blue light with high brightness under slow electron beam excitation of 100 V or less, leading to the completion of the present invention.

The luminescent composition of the present invention has a composition formula of CdO・wSnO ₂
(However, w is 0.1≦w≦10. The same applies hereinafter.) A cadmium-tin composite oxide represented by ZnS:Ag phosphor, ZnS:Ag, Al phosphor,
CaWO ₄ phosphor, Y ₂ SiO ₅ :Ce phosphor, (Ba, Mg)
O・6Al ₂ O ₃ : Eu ²⁺ fluorophore, Ca ₂ MgSiO ₅ : Ce fluorophore, Zn(S, Se): Ag fluorophore, Zn(S, Se):
Ag, Al phosphor, SrGa ₂ S ₄ :Ce phosphor, (Ca,
Mg) ₂ SiO ₄ :Ti phosphor, (Sr, Ba) ₃ (PO ₄ ) ₂ : Eu ²⁺
A phosphor and a blue-emitting phosphor that is one or more types of Ca ₂ B ₅ O ₉ Cl:Eu ²⁺ phosphor at a ratio of 1:19.
It is characterized by being mixed at a weight ratio of 4:1 to 4:1.

Further, the fluorescent display tube of the present invention has a structure in which an anode plate having a fluorescent film on one side and a cathode facing the fluorescent film are enclosed in a container having a vacuum inside. In the tube, the phosphor film is composed of a cadmium-tin composite oxide whose composition formula is _CdO.wSnO2, a ZnS:Ag phosphor, and a ZnS:Ag phosphor.
Ag, Al phosphor, CaWO ₄ phosphor, Y ₂ SiO ₅ :Ce phosphor, (Ba, Mg)O.6Al ₂ O ₃ :Eu ²⁺ phosphor,
Ca ₂ MgSiO ₅ : Ce phosphor, Zn (S, Se): Ag phosphor, Zn (S, Se): Ag, Al phosphor, SrGa ₂ S ₄ :
Ce phosphor, (Ca, Mg) ₂ SiO ₄ :Ti phosphor, (Sr,
Ba) ₃ (PO ₄ ) ₂ : Eu ²⁺ fluorophore and Ca ₂ B ₅ O ₉ Cl:
It is characterized by being composed of a luminescent composition in which one or more types of Eu ²⁺ fluorophores and a blue-emitting phosphor are mixed in a weight ratio of 1:19 to 4:1.

The present invention will be explained in detail below.

Compositional formula of the constituent components of the luminescent composition of the present invention
The cadmium/tin composite oxide represented by CdO/wSnO ₂ is CdO or cadmium oxalate (CC ₂ O ₄ ),
Cadmium compounds that can easily convert to CdO at high temperatures, such as cadmium carbonate (CdCO ₃ ) and cadmium chloride (CdCl ₂ ), and Sn ₂ O or cadmium oxalate (SnC ₂ O ₄ ), and tin nitrate [Sn(NO ₃ ) ₄ ] , a tin compound such as tin chloride (SnCl ₄ ) that can easily be converted into SnOB at high temperatures are weighed out and mixed so that the composition becomes CdO wSnO ₂ stoichiometrically. It can be obtained by firing for 0.5 to 4 hours. In _{particular ,} oxalic acid ( _{H 2 C 2 O 4} ) CdC ₂ C ₄ and SnC ₂ O ₄ obtained by adding a solution are stoichiometrically converted to CdO.
A mixed oxalate containing a proportion of wSnO ₂ is fired in advance at a temperature of 600°C to 690°C for 0.5 to 3 hours, then ground and mixed in a mortar, etc., and heated again to 700°C to 690°C.
The cadmium/tin composite oxide obtained by firing at a temperature of 1200°C for 1 to 4 hours has a small particle size and good conductivity. By using it as a component of the composition of the present invention, a light-emitting composition that emits light with higher brightness can be obtained. From the viewpoint of luminance, the more preferable w value range is 0.3≦w≦
2.0, and especially the best results are obtained when the w value is approximately 1.0. When the w value is smaller than 0.1 and when the w value is larger than 10, the luminance of the resulting composition is significantly reduced. Note that CdO and _SnO2
When using a mixed oxide obtained by simply mixing the two without reacting them at high temperature to form a cadmium-tin composite oxide, the luminescent composition of the present invention exhibits high-intensity light emission. The luminescent composition shown cannot be obtained.

On the other hand, it is used as a blue-emitting phosphor, which is another component of the luminescent composition of the present invention.
ZnSS: Ag phosphor, ZnS: Ag, Al phosphor,
CaWO ₄ phosphor, Y ₂ SiO ₅ :Ce phosphor, (Ba, Mg)
O・6Al ₂ O ₃ : Eu ²⁺ fluorophore, Ca ₂ MgSiO ₅ : Ce fluorophore, Zn(S, Se): Ag fluorophore, Zn(S, Se):
Ag, Al phosphor, SrGa ₂ S ₄ :Ce phosphor, (Ca,
Mg) ₂ SiO ₄ :Ti phosphor, (Sr, Ba) ₃ (PO ₄ ) ₂ : Eu ²⁺
The phosphor and the Ca ₂ B ₅ O ₉ Cl:Eu ²⁺ phosphor were manufactured by conventionally known manufacturing methods. Among these phosphors, ZnS:Ag phosphor, ZnS:
Ag, Al phosphor, Zn (S, Se): Ag phosphor, Zn
(S, Se): Ag, Al fluorophore, CaWO ₄ fluorophore,
Y ₂ SiO ₅ :Ce phosphor and (Ba, Mg)O.
Preferably, 6Al ₂ O ₃ :Eu ²⁺ phosphors are used, more preferably ZnS:Ag phosphors, ZnS:Ag, Al phosphors, Zn(S,Se):Ag phosphors and Zn( S,
Se): Ag, Al fluorophore.

The luminescent composition of the present invention can be obtained by sufficiently mixing the above-mentioned cadmium/tin composite oxide and blue luminescent phosphor in a mortar, ball mill, mixer mill, or the like. Both are mixed in a weight ratio such that the value of cadmium/tin composite oxide/blue light-emitting phosphor is 1/19 to 4/1. The reason why a blue-emitting phosphor, which hardly emits light under excitation with a slow electron beam, becomes able to emit light with high brightness under excitation with a slow electron beam by mixing cadmium-tin composite oxide with it is as follows. mixed cadmium
This is because the tin complex oxide plays a role in preventing charge up during excitation, and as a result, the blue-emitting phosphor can be excited efficiently.
When the value of cadmium-tin composite oxide/blue-emitting phosphor is less than 1/19, this charge-up prevention effect by the cadmium-tin composite oxide cannot be obtained, and therefore the composition has the property of emitting blue light. It is similar to a phosphor, and does not emit light under low-speed electron beam excitation. On the other hand, when the value of cadmium/tin composite oxide/blue emitting phosphor is greater than 4/1, the resulting composition emits very weak light. This is thought to be because although the charge-up prevention effect is sufficient, the cadmium-tin composite oxide blocks light emission from the phosphor. From the viewpoint of luminance, the value of the cadmium-tin composite oxide/blue-emitting phosphor is preferably 1/9 to 3/2.

Figure 3 shows the luminescent composition of the present invention, which is a mixture of a cadmium-tin composite oxide whose composition formula is CdO.SnO ₂ and a ZnS:Ag phosphor.
1 is a graph showing the relationship between the mixing weight ratio of CdO·SnO ₂ and ZnS:Ag phosphor and the luminescence brightness of the obtained luminescent composition under slow electron beam excitation.

As is clear from Figure 3, CdO・SnO ₂ /
When the value of ZnS:Ag phosphor is smaller than 1/19 and larger than 4/1, the luminance of the luminescent composition obtained is extremely low, and when the value of CdO/SnO ₂ /
When the value of the ZnS:Ag phosphor is in the range of 1/9 to 3/2, a luminescent composition that emits light with particularly high brightness can be obtained. Furthermore, Figure 3 shows CdO/SnO ₂ and ZnS:Ag.
This is a graph about a luminescent composition mixed with a phosphor, but when a cadmium/tin composite oxide other than CdO/SnO ₂ is used, and when another blue luminescent material is used instead of the ZnS:Ag phosphor. Even when used, the relationship between the mixing weight ratio of the cadmium-tin composite oxide and the blue-emitting phosphor and the luminance of the resulting composition shows almost the same tendency as the graph shown in Figure 3. confirmed.

The luminescent composition of the present invention obtained as described above has an accelerating voltage of 1 KV or less, especially when the mixing weight ratio of the conductive material and the blue luminescent phosphor is the same.
Under slow electron beam excitation of 100 V or less, it exhibits higher luminance than a luminescent composition made by mixing SnO ₂ and the blue-emitting phosphor, and the accelerating voltage is approximately
When the voltage is higher than 80V, the luminescent composition exhibits higher luminance than a luminescent composition formed by mixing In ₂ O ₃ and the blue luminescent phosphor. Furthermore, CdO・wSnO ₂ which is a component of the luminescent composition of the present invention is similar to SnO ₂ and ZnO.
It is inexpensive compared to In ₂ O ₃ and therefore the luminescent compositions of the present invention are cheaper than luminescent compositions using In ₂ O ₃ .

Figure 4 shows the relationship between acceleration voltage and luminance (curve a) of the luminescent composition of the present invention, which is a mixture of CdO.SnO ₂ and ZnS:Ag phosphor at a weight ratio of 2:3.
Same as SnO ₂ , ZnO, In ₂ O ₃ and CdO respectively
Relationship between acceleration voltage and luminance of four types of luminescent compositions containing ZnS:Ag phosphor at the same weight ratio (curves b, c, d and e, respectively) and ZnS:
It is a graph showing a comparison between the relationship (curve f) between accelerating voltage and luminance in the case of an Ag phosphor alone. As is clear from FIG. 4, the luminescent composition of the present invention (curve a) is different from the three conventional luminescent compositions (curves b, c and d, respectively) using SnO ₂ , ZnO and In ₂ O ₃ respectively. is also its constituent component.
The luminescence brightness under slow electron beam excitation is significantly higher than that of the ZnS:Ag phosphor (curve f).
Furthermore, as is clear from the comparison between curve a and curves b and c, the luminescent composition of the present invention is not only a luminescent composition using ZnO (curve c) but also a luminescent composition using SnO ₂ (curve b). ) has higher emission brightness under slow electron beam excitation. Furthermore, curve a
As is clear from the comparison between curve d and curve d, under slow electron beam excitation with an accelerating voltage higher than about 80 V, the luminescent composition of the present invention (curve a) is more similar to the luminescent composition using In ₂ O ₃ (curve a). It shows luminescence with higher brightness than curve d). The light-emitting composition of the present invention using CdO・wSnO ₂ is
It was completely unexpected that the luminescent composition would exhibit higher luminance than a luminescent composition using SnO ₂ . This is because, as shown by curve e in Figure 4,
The luminescence brightness of the luminescent composition using CdO under slow electron beam excitation is significantly lower than that of the luminescent composition using SnO ₂ (curve _b ), and therefore This is because it was inconceivable that using a composite oxide would produce higher luminance than when using SnO ₂ . Furthermore, the fourth
The figure is a graph when a ZnS:Ag phosphor is used as the blue-emitting phosphor and the mixing weight ratio of the conductive material and the ZnS:Ag phosphor is 2:3, but other blue-emitting phosphors may also be used. The acceleration voltage-emission brightness curve of the luminescent composition of the present invention and the three conventional luminescence curves using SnO ₂ , ZnO and In ₂ O ₃ when using a luminous material and when changing the mixing weight ratio It was confirmed that the relationship between the accelerating voltage and luminance luminance curve of the composition showed the same tendency as shown in FIG.

The fluorescent display tube of the present invention is manufactured by the method described below. The luminescent composition described above is first coated by precipitation coating onto an anode plate, usually supported by a ceramic substrate, to form a fluorescent film. That is, an anode plate is placed in a suspension in which the composition is dispersed in water, and the composition is applied by settling on one side of the anode plate by its own weight, and then the water is removed and the coating is dried. let In order to improve the adhesion of the fluorescent film obtained in this case to the anode plate, a small amount (0.01 to 0.1%) of water glass may be added to the suspension. Also, the coating density is 5 mg/cm ² ~ 30
mg/cm ² is appropriate. Although the above-mentioned precipitation coating method is generally used as a method for forming a fluorescent film and is widely practiced, the method for forming a fluorescent film in the fluorescent display tube of the present invention is not limited to this precipitation coating method. .
Next, a linear heater is placed with a cathode coated with oxides such as BaO, CaO, SnO, etc. facing the fluorescent film on the anode plate with an interval of about 1 mm to 5 mm, and this pair of electrodes After placing it in a transparent container such as glass, the inside of the container is evacuated. After the inside of the container reaches a vacuum level of at least 10 ^-5 Torr, stop the exhaust and seal it. After sealing, the getter is removed to further increase the vacuum inside the container. In this manner, the fluorescent display tube of the present invention can be obtained.

Note that the fluorescent film on the anode plate is flat,
Since the cathode is linear, it is desirable to install a mesh-like grid electrode as a diffusion electrode between the cathode and the fluorescent film, as shown in FIG. 2, in order to diffuse the low-speed electron beam emitted from the cathode. In this case, better results can be obtained if the mesh is as narrow as possible so that the loss of the amount of light emitted by the fluorescent film is small and the low-velocity electron beam is well diffused. Specifically, it is desirable that the diameter of the mesh is 500 microns or less, and the aperture ratio (the area of the holes that transmit low-speed electron beams relative to the total area of the grid electrode) is 50% or more. An anode plate can display any character or figure by dividing its electrode form into the required character or figure shapes and making it possible to selectively apply the required voltage to each electrode. be able to. In addition, by dividing the anode plate into dots or lines and forming a fluorescent film of a luminescent composition that emits light in a color other than blue on some of the electrodes, a fluorescent film that can display multiple colors can be used. You can get a display tube.

As explained above, the blue light emitting composition of the present invention is different from the conventional blue light emitting composition disclosed in JP-A No. 54-5887.
This is an improved blue-emitting composition that uses SnO ₂ and exhibits higher luminance than the blue-emitting composition that uses SnO ₂ under slow electron beam excitation at an accelerating voltage of 1KV or less, especially 100V or less. . Furthermore, the blue light-emitting composition of the present invention has an accelerating voltage of approximately 80V.
Under higher slow electron beam excitation than conventional
It exhibits higher luminance than a blue-emitting composition using In ₂ O ₃ . Furthermore, the blue-emitting composition of the present invention has a great practical advantage of being cheaper than the conventional blue-emitting composition using In ₂ O ₃ . In this way, the present invention has an acceleration voltage of 1KV or less.
The present invention provides an extremely practical blue light-emitting composition that emits high-intensity light especially under slow electron beam excitation of 100 V or less, and a blue-light-emitting fluorescent display tube having a fluorescent film made of this blue light-emitting composition. Its industrial utility value is great.

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

Example 1 1 mol of CdC ₂ O ₄ and 1 mol of SnC ₂ O ₄ were thoroughly mixed,
The fired product was fired at 680°C for 1 hour, cooled, mixed again in a mortar, and fired at 1000°C for 2 hours to produce cadmium, whose composition formula is _CdO.SnO2 .
A tin composite oxide was obtained. 2 parts by weight of the obtained CdO.SnO ₂ and 3 parts by weight of ZnS:Ag phosphor were thoroughly mixed in a mortar. 100 mg of the obtained composition was added to 100 c.c. of distilled water and subjected to ultrasonic dispersion. A 2 cm x 1 cm aluminum anode plate supported by a ceramic substrate was placed in this dispersion, and after being left for 30 minutes, the supernatant was removed and dried to form a fluorescent film. Next, a cathode made of a tungsten wire heater coated with oxide is placed facing the fluorescent film on the anode plate with an interval of approximately 5 mm, and this pair of electrodes is placed in a hard glass container. , the inside of the container was evacuated. After the degree of vacuum inside the container reached approximately 10 ^-5 Torr, the exhaust was stopped and the container was sealed, and then the getter was blown off to further increase the degree of vacuum inside the container. In this way, a fluorescent display tube having the structure shown in FIG. 1 was obtained. This fluorescent display tube emitted blue light with a luminance of 65 ft-L when the voltage applied to the anode plate was 90V. On the other hand, in the same manner as above, a luminescent composition was prepared by mixing 2 parts by weight of SnO ₂ and 3 parts by weight of a ZnS:Ag phosphor, and 2 parts by weight of In ₂ O ₃ and 3 parts by weight of a ZnS:Ag phosphor. Fluorescent display tubes each having a fluorescent film made of a luminescent composition prepared by mixing the above were prepared. These fluorescent display tubes emitted blue light with luminances of 55 ft-L and 60 ft-L, respectively, when the voltage applied to the anode plate was 90 V.

Example 2 A blue-emitting composition was obtained in the same manner as in Example 1, except that ZnS:Ag, Al phosphor was used as the blue-emitting phosphor. Using the obtained composition, a fluorescent display tube having the structure shown in FIG. 1 was obtained in the same manner as in Example 1. This fluorescent display tube has a voltage applied to the anode plate.
At 90V, blue light was emitted with a luminance of 40ft-L. Meanwhile, add 2 parts by weight of SnO ₂ in the same manner as above.
A luminescent composition prepared by mixing 3 parts by weight of ZnS:Ag, Al phosphor and 2 parts by weight of In ₂ O ₃ and ZnS:Ag, Al
Fluorescent display tubes each having a fluorescent film made of a luminescent composition prepared by mixing 3 parts by weight of a fluorescent material were prepared. These fluorescent display tubes have luminance of 36 ft-L and 38 ft-L, respectively, when the applied voltage to the anode plate is 90 V.
It showed blue light emission.

Example 3 2 mol of CdC ₂ O ₄ and 1 mol of SnC ₂ O ₄ were thoroughly mixed,
The fired product was fired at 690°C for 1 hour, cooled, mixed again in a mortar, and fired at a temperature of 1050°C for 2 hours to produce a cadmium/tin composite oxide whose composition formula is CdO・0.5SnO ₂ I got it. The obtained CdO・
1 part by weight of 0.5SnO ₂ and 1 part by weight of CaWO ₄ phosphor were thoroughly mixed in a mortar to obtain a blue luminescent composition. Using the obtained composition, a fluorescent display tube having the structure shown in FIG. 1 was obtained in the same manner as in Example 1. This fluorescent display tube emitted blue light with a luminance of 10 ft-L when the voltage applied to the anode plate was 90V. On the other hand, a luminescent composition formed by mixing 1 part by weight of SnO ₂ and 1 part by weight of CaWO ₄ phosphor, and a luminescent composition formed by mixing 1 part by weight of In ₂ O ₃ and 1 part by weight of CaWO ₄ phosphor. Fluorescent display tubes were fabricated using each material as a fluorescent film. These fluorescent display tubes emitted blue light with luminances of 8.8 ft-L and 9.6 ft-L, respectively, when the voltage applied to the anode plate was 90V.

Example 4 3 parts by weight of CdO·SnO ₂ obtained in the same manner as in Example 1 and 7 parts by weight of Zn(S,Se):Ag phosphor were thoroughly mixed in a mortar to obtain a blue luminescent composition. . Using the obtained composition, a fluorescent display tube having the structure shown in FIG. 1 was obtained in the same manner as in Example 1. In this fluorescent display tube, when the voltage applied to the anode plate is 90V, the luminance is
It showed blue light emission at 60ft-L. On the other hand, a luminescent composition formed by mixing 3 parts by weight of SnO ₂ and 7 parts by weight of a Zn(S,Se):Ag phosphor, and ₃ parts by weight of In ₂ O and Zn
(S, Se): Fluorescent display tubes each having a fluorescent film made of a luminescent composition prepared by mixing 7 parts by weight of an Ag phosphor were prepared. These fluorescent display tubes have a luminance of 48 ft-L and
It showed blue light emission of 53 ft-L.

Example 5 1 mol of CdC ₂ O ₄ and 1.1 mol of SnC ₂ O ₄ were thoroughly mixed, and the composition formula obtained in the same manner as in Example 1 was obtained.
1 part by weight of a cadmium-tin composite oxide represented by CdO.1.1SnO ₂ and 4 parts by weight of a Y ₂ SiO ₅ :Ce phosphor were thoroughly mixed in a mortar to obtain a blue-emitting composition. The first step was carried out in the same manner as in Example 1 using the obtained composition.
A fluorescent display tube having the structure shown in the figure was obtained. This fluorescent display tube emitted blue light with a luminance of 42 ft-L when the voltage applied to the anode plate was 90V. on the other hand,
A luminescent composition prepared by mixing 1 part by weight of SnO ₂ and 4 parts by weight of Y ₂ SiO ₅ :Ce phosphor, and 1 part by weight of In ₂ O ₃ .
Fluorescent display tubes each having a fluorescent film made of a luminescent composition prepared by mixing Y ₂ SiO ₅ :Ce phosphor in an amount of 4 parts by weight were prepared. These fluorescent display tubes have luminance of 38ft-L and 40ft when the applied voltage to the anode plate is 90V.
-L blue light emission was shown.

Example 6 The composition formula obtained in the same manner as in Example 3 except that 1 mol of CdC ₂ O ₄ and 0.75 mol of SnC ₂ O ₄ was used was CdO.
3 parts by weight of cadmium/tin composite oxide represented by 0.75SnO ₂ and 7 parts by weight of (Ba, Mg)O.6Al ₂ O ₃ :Eu ²⁺ phosphor were thoroughly mixed in a mortar to form a blue luminescent material. Obtained. Example 1 using the obtained luminescent composition
In the same manner as above, a fluorescent display tube having the structure shown in FIG. 1 was obtained. This fluorescent display tube emitted blue light with a luminance of 34 ft-L when the voltage applied to the anode plate was 90V. On the other hand, 3 parts by weight of SnO ₂ and 0.
6Al ₂ O ₃ : A luminescent composition prepared by mixing 7 parts by weight of Eu ²⁺ phosphor, 3 parts by weight of In ₂ O ₃ and (Ba, Ma)O.
Fluorescent display tubes each having a fluorescent film made of a luminescent composition prepared by mixing 7 parts by weight of _{6Al 2} O ₃ :Eu ²⁺ phosphor were prepared. These fluorescent display tubes have a luminance of 30ft-L and 32ft when the applied voltage to the anode plate is 90V.
-L blue light emission was shown.

[Brief explanation of the drawing]

1 and 2 are schematic diagrams of typical examples of fluorescent display tubes, with FIG. 1 being a diode and FIG. 2 being a triode. Figure 3 shows CdO/SnO ₂ and CdO/SnO ₂ in a luminescent composition containing a mixture of CdO/SnO 2 and ZnS:Ag phosphor.
It is a graph showing the relationship between the mixing weight ratio of ZnS:Ag phosphor and the luminescence brightness of the composition. Figure 4 is
The relationship between acceleration voltage and luminance (curve a) of the luminescent composition of the present invention in which CdO.SnO ₂ and ZnS:Ag phosphor are mixed at a weight ratio of ₂ :3 is expressed as follows:
Relationship between accelerating voltage and luminance of four types of luminescent compositions in which In ₂ O ₃ and CdO are mixed with the same ZnS:Ag phosphor at the same weight ratio (curves b,
3 is a graph comparing the relationship between accelerating voltage and emission brightness (curve f) in the cases of c, d and e) and the case of ZnS:Ag phosphor alone. 11... Anode plate, 12... Fluorescent film, 13
... Ceramic substrate, 14 ... Cathode, 15 ... Grid electrode, 16 ... Container, 17 ... Inside of display tube kept in high vacuum.

Claims (1)

[Claims] 1. The compositional formula is CdO・wSnO ₂ (where w is 0.1≦w≦
A complex oxide of cadmium and tin represented by 10), a silver-activated zinc sulfide phosphor (ZnS:Ag), and a silver- and aluminum-activated zinc sulfide phosphor (ZnS:Ag). , Al), self-activated calcium tungstate phosphor (CaWO ₄ ), cerium-activated yttrium silicate phosphor (Y ₂ SiO ₅ :Ce), europium-activated barium/magnesium aluminate phosphor [(Ba, Mg) O・6Al ₂ O ₃ :Eu ²⁺ ], cerium-activated calcium/magnesium silicate phosphor (Ca ₂ MgSiO ₅ :Ce), silver-activated zinc sulfur selenide phosphor [Zn(S, Se) :Ag], silver and aluminum activated zinc sulfur selenide phosphor [Zn(S,Se):
Ag, Al], cerium-activated strontium-gallium sulfide phosphor (SrGa ₂ S ₄ :Ce), titanium-activated calcium-magnesium silicate phosphor [(Ca,
Mg) ₂ SiO ₄ :Ti], europium-activated strontium barium phosphate phosphor [(Sr, Ba) ₃ (PO ₄ ) ₂ :
Eu ²⁺ ] and a blue-emitting phosphor that is one or more of europium-activated calcium chloroborate phosphors (Ca ₂ B ₅ O ₉ Cl:Eu ²⁺ ) at 1:19 to 4 A blue light-emitting composition mixed at a weight ratio of :1. 2. The blue light-emitting composition according to claim 1, wherein a mixing weight ratio of the cadmium-tin composite oxide and the blue light-emitting phosphor is 1:9 to 3:2. 3. The blue light-emitting composition according to claim 1 or 2, wherein the w is a number satisfying the condition of 0.3≦w≦2.0. 4. The blue light-emitting composition according to claim 3, wherein the w is 1.0. 5. The blue light-emitting phosphor according to any one of claims 1 to 4, wherein the blue-emitting phosphor is composed only of the silver-activated zinc sulfide phosphor (ZnS:Ag). Composition. 6. Any one of claims 1 to 4, characterized in that the blue-emitting phosphor consists of only the silver- and aluminum-activated zinc sulfide phosphor (ZnS:Ag, Al). The blue light emitting composition described. 7. Claims 1 to 4, characterized in that the blue-emitting phosphor is composed only of the silver-activated zinc sulfur selenide phosphor [Zn(S,Se):Ag].
The blue-emitting composition according to any one of the above items. 8 The blue-emitting phosphor is the silver- and aluminum-activated zinc sulfur selenide phosphor [Zn(S,
5. The blue light-emitting composition according to any one of claims 1 to 4, characterized in that it consists of only Se):Ag, Al]. 9. In a low-speed electron beam-excited fluorescent display tube having a structure in which an anode plate having a fluorescent film on one side and a cathode facing the fluorescent film are enclosed in a vacuum container, the above-mentioned Fluorescent film composition formula
A composite oxide of cadmium and tin expressed as CdO・wSnO ₂ (where w is a number satisfying the condition 0.1≦w≦10), silver-activated zinc sulfide phosphor (ZnS:Ag), silver and aluminum-activated zinc sulfide phosphor (ZnS:Ag, Al), self-activated calcium tungstate phosphor (CaWO ₄ ), cerium-activated yttrium silicate phosphor (Y ₂ SiO ₅ :Ce), with europium. Active barium/magnesium aluminate phosphor [(Ba, Mg)O・6Al ₂ O ₃ : Eu ²⁺ ], cerium activated calcium/magnesium silicate phosphor (Ca ₂ MgSiO ₅ : Ce), silver activated sulfur Zinc selenide phosphor [Zn(S,Se):Ag], silver and aluminum activated sulfurized zinc selenide phosphor [Zn(S,Se):
Ag, Al], cerium-activated strontium-gallium sulfide phosphor (SrGa ₂ S ₄ :Ce), titanium-activated calcium-magnesium silicate phosphor [(Ca,
Mg) ₂ SiO ₄ :Ti], europium-activated strontium barium phosphate phosphor [(Sr, Ba) ₃ (PO ₄ ) ₂ :
Eu ²⁺ ] and a blue-emitting phosphor that is one or more of europium-activated calcium chloroborate phosphors (Ca ₂ B ₅ O ₉ Cl:Eu ²⁺ ) at 1:19 to 4 1. A low-speed electron beam excited fluorescent display tube comprising a blue light-emitting composition mixed in a weight ratio of :1. 10 The mixing weight ratio of the composite oxide of cadmium and tin and the blue light emitting phosphor is 1:9 to 3:2.
A low-speed electron beam-excited fluorescent display tube according to claim 9, characterized in that: 11. The low-speed electron beam excited fluorescent display tube according to claim 9 or 10, wherein the w is a number satisfying the condition 0.3≦w≦2.0. 12. The low-speed electron beam excited fluorescent display tube according to claim 11, wherein said w is 1.0. 13. The slow electron according to any one of claims 9 to 12, wherein the blue-emitting phosphor is composed only of the silver-activated zinc sulfide phosphor (ZnS:Ag). Line-excited fluorescent display tube. 14 Claim 9, characterized in that the blue-emitting phosphor consists only of the silver- and aluminum-activated zinc sulfide phosphor (ZnS:Ag, Al).
13. A low-speed electron beam-excited fluorescent display tube according to any one of Items 1 to 12. 15. Any one of claims 9 to 12, characterized in that the blue-emitting phosphor is composed only of the silver-activated zinc sulfur selenide phosphor [Zn(S,Se):Ag]. The low-speed electron beam-excited fluorescent display tube described in the above item. 16 The blue-emitting phosphor is composed of the silver- and aluminum-activated zinc sulfur selenide phosphor [Zn(S,
The low-speed electron beam-excited fluorescent display tube according to any one of claims 9 to 12, characterized in that it consists of only Se):Ag, Al].