JPH0564677B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a phosphor. More specifically, the present invention relates to a phosphor that exhibits a sublinear current density-emission brightness relationship as the current density of a stimulating electron beam increases.

[Prior Art] Recently, multicolor cathode ray tubes have come into practical use as end display devices for computers, display devices for aircraft control systems, and the like. This multicolor cathode ray tube consists of a phosphor that exhibits a superlinear excitation energy-emission brightness relationship as the energy of the stimulating electron beam increases, and a phosphor that exhibits a sublinear excitation energy-emission brightness relationship as the energy of the stimulating electron beam increases. This is a cathode ray tube that has a phosphor film composed of two types of phosphors that emit light in different colors.The emitted light color of the phosphor film is changed by changing the energy of the stimulating electron beam. This system is designed to perform multicolor display.

The multicolor cathode ray tubes are classified into two types depending on the method of changing the energy of the stimulating electron beam. In other words, the energy of the stimulating electron beam is changed by changing the accelerating voltage, and the energy of the stimulating electron beam is changed by changing the current density. It is called a cathode ray tube, and the latter is called a current modulated multicolor cathode ray tube. For example, regarding voltage modulated multicolor cathode ray tubes, see pages 106-117 of the July 2, 1973 issue of Nikkei Electronics.
Regarding the current modulation type multicolor cathode ray tube, please refer to Japanese Patent Publication No. 52-5225.

Current modulated multicolor cathode ray tubes have the advantage that the structure of the electron gun, electron gun control circuit, etc. are significantly simpler than voltage modulated multicolor cathode ray tubes. Despite this, most of the multicolor cathode ray tubes currently being put into practical use are voltage modulated multicolor cathode ray tubes. This indicates that there are few phosphors suitable for use in current-modulated multicolor cathode ray tubes, ie, phosphors that exhibit a sufficiently superlinear or sublinear current density-luminance relationship as the current density of the stimulating electron beam increases. This is because they have not been

Conventionally, copper and aluminum activated phosphors containing an appropriate amount of at least one metal selected from iron, cobalt, and nickel have been used as phosphors that exhibit a superlinear current density-emission brightness relationship when the current density of the stimulating electron beam increases. A zinc sulfide green-emitting phosphor (ZnS: Cu, Al) and a silver-activated zinc sulfide cadmium blue-green to red-emitting phosphor [(Zn, Cd)S:Ag, as is well known, this phosphor exhibits blue-green to red light emission in response to changes in the molar ratio of ZnS and CdS]. Furthermore, a manganese-activated zinc silicate green-emitting phosphor (Zn ₂ SiO ₄ :Mn) is known as a phosphor that exhibits a sublinear current density-emission brightness relationship when the current density of the stimulating electron beam increases.

In multicolor cathode ray tubes, in order to widen the range of display color change, a combination of a red-emitting phosphor that exhibits a superlinear excitation energy-emission brightness relationship and a green-emitting phosphor that exhibits a sublinear excitation energy-emission brightness relationship is generally used. or a combination of a blue-green to green-emitting phosphor exhibiting a super-linear excitation energy-emission brightness relationship and a red-emitting phosphor exhibiting a sub-linear excitation energy-emission brightness relationship, the phosphor film is constructed by Ru. From this point of view, current modulating multicolor cathode ray tubes use (Zn, Cd)S containing at least one metal among the above iron, cobalt, and nickel:
Ag red-emitting phosphor (showing super-linear current density-emission brightness relationship) and the above Zn ₂ SiO ₄ :Mn
A combination with a green-emitting phosphor (which exhibits a sublinear current density-emission brightness relationship) is being considered, but ZnS containing at least one metal from the above iron, cobalt, and nickel:
A green-emitting phosphor or a (Zn, Cd)S:Ag blue-green to green-emitting phosphor containing at least one metal selected from the above-mentioned iron, cobalt, and nickel (both have a superlinear current density-emission brightness relationship). A red-emitting phosphor that exhibits a sufficiently sublinear current density-emission brightness relationship as the current density of the stimulating electron beam increases is highly desirable.

The present invention was made under the above-mentioned circumstances, and provides a phosphor, in particular a red-emitting phosphor, which exhibits a sufficiently sublinear current density-emission brightness relationship when the current density of a stimulating electron beam increases. The purpose is to

Compositional formula Ln ₂ O ₂ S: Eu (However, Ln is yttrium, gadolinium,
At least one of lanthanum and lutetium
It is well known that the europium-activated rare earth oxysulfide phosphor represented by the following species exhibits high-intensity yellow to red light emission in response to changes in the amount of Eu activation under electron beam excitation. For example, one of these phosphors,
Y ₂ O ₂ S:Eu phosphor, which has a relatively large amount of Eu activation, is currently in practical use as a red-emitting component phosphor for color television cathode ray tubes.

It is known that the Ln ₂ O ₂ S:Eu phosphor exhibits a very slightly sublinear current density-emission brightness relationship as the current density of the stimulating electron beam increases, as illustrated in FIG.

In order to achieve the above object of the present invention, the present inventors have discovered that the current density exhibited by Ln ₂ O ₂ :Eu phosphor -
We have conducted various studies to improve the sublinearity of the luminance relationship. As a result, when M (M is at least one of titanium and tin) is used as a co-activator for Eu, the current density-emission brightness relationship shown by the Ln ₂ O ₂ S:Eu phosphor is It was discovered that it is possible to increase the sublinearity of
issue). Furthermore, M (M is at least one of titanium and tin) as a co-activator for Eu
When using M′ (M′ is at least one of calcium and cerium) in a specific range,
Ln ₂ O ₂ S: Eu, M (M is at least one of titanium and tin) The sublinearity of the current density-emission brightness relationship exhibited by the phosphor can be increased, and this M (M is at least one of titanium and tin) and M'(M' is at least one of calcium and cerium)
The present inventors have discovered that in a specific range of the coactivation amount, the above sublinearity becomes significantly high and a stable and good phosphor can be obtained, and the present invention has been completed.

[Means for solving the problems] The phosphor of the present invention has a composition formula of Ln ₂ O ₂ S: Eu _x M _y M′ _z (where Ln is yttrium, gadolinium,
At least one of lanthanum and lutetium
M is at least one of titanium and tin, M' is at least one of calcium and cerium, and x, y and z are each 2×10 ^-4 ≦x≦0.18 ,5× ^10-6
Europium, ^M (M is at least one of titanium ^{and tin} ) and
M'(M' is at least one of calcium and cerium) activated rare earth oxysulfide phosphor. When the current density of the stimulating electron beam increases, this phosphor has a higher sublinearity than the Ln ₂ O ₂ S: Eu, M (M is at least one of titanium and tin) phosphor. It shows the brightness relationship, especially the z of the coactivation amount of M′ (M′ is at least one of calcium and cerium).
A phosphor having a value in the range of 5×10 ⁻⁵ ≦z≦2×10 ⁻² exhibits a current density-emission luminance relationship with significantly high sublinearity.

The phosphor of the present invention is manufactured by the manufacturing method described below.

First, as raw materials for the phosphor, a first compound group consisting of yttrium oxide (Y ₂ O ₃ ), gadolinium oxide (Gd ₂ O ₃ ), lanthanum oxide (La ₂ O ₃ ), and lutetium oxide (Lu ₂ O ₃ ), and nitrates, sulfates, carbonates, oxalates, hydroxides, etc. easily at high temperatures such as Y ₂ O ₃ , Gd ₂ O ₃ ,
At least one compound selected from _the second compound group consisting of yttrium compounds, gadolinium compounds, lanthanum compounds, and lutetium compounds that can be converted into La ₂ O ₃ and Lu ₂ O 3 2 Europium oxide (Eu ₂ O ₃ ) and nitrate ,
At least one compound selected from the group of compounds consisting of europium compounds that can be easily converted to Eu ₂ O ₃ at high temperatures, such as sulfates, carbonates, oxalates, and hydroxides; 3. Titanium oxide (TiO ₂ ) and sulfates; , at least one compound selected from the group consisting of titanium compounds that can be easily converted into oxides at high temperatures such as hydroxides, 4. tin oxide (SnO ₂ ) and nitrates, sulfates,
At least one compound selected from the group of compounds consisting of tin compounds that can be easily converted into oxides at high temperatures such as hydroxide, 5. Cerium oxide (CeO ₂ ), and nitrates, sulfates, carbonates, oxalates, and hydroxides. At least one compound selected from the group consisting of cerium compounds that can be easily converted to oxides at high temperatures such as 6. Calcium oxide (CaO) and carbonates, hydroxides, nitrates, etc. that can be easily converted to CaO at high temperatures. At least one compound selected from the group consisting of variable calcium compounds; 7. Sulfur; 8. Alkali commonly used in the production of oxysulfide phosphors, such as sodium carbonate (Na ₂ CO ₃ ), potassium phosphate (K ₃ PO ₄ ), etc. Fluxing agents such as metal salts are used.

The above 1) and 7) are the base raw materials, the above 2) is the Eu activator raw material, and the above 3) is the Ti
4) is a raw material for a coactivator, 4) is a raw material for a Sn coactivator, and 5) is a raw material for a Ce coactivator,
6) is a Ca co-activator raw material. Above 1), 2),
3), 4), 5) and 6) have the stoichiometric formula Ln ₂ O ₂ :Eu _x M _y M′ _z (where Ln is yttrium, gadolinium,
At least one of lanthanum and lutetium
M is at least one of titanium and tin, M' is at least one of calcium and cerium, and x, y and z are each 2×10 ^-4 ≦x≦0.18 ,5× ^10-6
y≦5×10 ⁻² and 2×10 ⁻⁶ ≦z≦6×10 ⁻² ). The above 7) is 30 to 30% of the above mixed oxide.
It is used in an amount corresponding to 60%, and 8) is used in an amount corresponding to 5 to 50% by weight of the mixed oxide. Weigh out the required amount of each phosphor raw material and mix thoroughly to obtain a phosphor raw material mixture.

Next, the obtained phosphor raw material mixture is filled into a heat-resistant container such as an alumina crucible or a quartz crucible, and fired. Firing takes place in air at temperatures of 900 to 1500°C. The firing time varies depending on the amount of the phosphor raw material mixture filled in the heat-resistant container, the firing temperature used, etc., but is generally 0.5 to 5 hours.
After firing, the obtained fired product is washed and dried to obtain the phosphor of the present invention.

When the current density of the stimulating electron beam increases, the phosphor of the present invention exhibits a sublinear current density-emission brightness relationship. The sublinearity of the current density-emission brightness relationship exhibited by the phosphor of the present invention is the same for the Eu activation amount and the M (M is at least one of titanium and tin) coactivation amount.
Ln ₂ O ₂ S: Eu, M (M is at least one of titanium and tin) Higher than the sublinearity of the current density-emission luminance relationship exhibited by the phosphor.

FIG _. 1 is _{a graph} illustrating _the current density-emission brightness relationship exhibited by the phosphor _of the present invention. - It shows the luminance luminance relationship. In Figure 1, the luminance on the vertical axis is the luminance of the Y ₂ O ₂ S:Eu _0.08 , Ti _0.0005 phosphor at each current density value.
Multiplying the specific luminance set to 100% by a certain magnification
It is standardized so that the value at 1 μA/cm ² is 100.

The following can be understood from Figure 1. In other words, since the Y ₂ O ₂ S: Eu _0.08 , Ti _0.0005 phosphor shows a sublinear current density-emission brightness relationship, it is clear that
Y ₂ O ₂ S: Eu _0.08 , Ti _0.0005 , Ca _0.005 phosphors exhibit a sublinear current density-emission brightness relationship, and the sublinearity of the current density-emission brightness relationship is
Eu activation amount and Ti coactivation amount are the same
Y ₂ O ₂ S: higher than the sublinearity of the current density-emission luminance relationship exhibited by the Eu _0.08 , Ti _0.0005 phosphor.

The sublinearity of the current density-emission brightness relationship exhibited by the phosphor of the present invention is determined by the coactivation amount of M (M is at least one of titanium and tin) and M'(M' is the amount of calcium and cerium). (at least one of them) is a function of the amount of co-activation. For example, if the current density of the stimulating electron beam is 1.0 μA/cm ² and
_Y2O2S at _6.0μA / ^cm2 : Eu _0.08 , Ti _0.0005 ,
If the luminance of the Ca _z phosphor is A ₁ and B _1, respectively, then the current density exhibited by this phosphor is -
The sublinearity related to luminance is expressed as B ₁ /A ₁ (of course, the smaller the value of B ₁ /A ₁ , the higher the sublinearity), but this sublinearity is determined by the amount of Ca coactivation. It changes depending on.

Figure 2 shows the relationship between the amount of Ca coactivation of the Y ₂ O ₂ S: Eu _0.08 , Ti _0.0005 , Ca _z phosphor and the sublinearity of the current density-emission brightness relationship exhibited by this phosphor. It is a graph. In FIG. 2, the vertical axis representing sublinearity is indicated by the value of B ₁ A ₂ /A ₁ B ₂ . Here A ₂ and B ₂ are respectively
Current density of Y ₂ O ₂ S: Eu _0.08 , Ti _0.0005 , Ca _z phosphor and Y ₂ O ₂ S: Eu _0.08 , Ti _0.0005 phosphor whose Eu activation amount and Ti coactivation amount are the same
Emission brightness at 1.0 μA/cm ² and 6.0 μA/cm ² . The fact that the value of B ₁ A ₂ /A ₁ B ₂ is smaller than 1 means that the sublinearity of the current density-emission luminance relationship exhibited by Y ₂ O ₂ S: Eu _0.08 , Ti _0.0005 , Ca _z phosphors is is higher than the sublinearity of the current density-emission brightness relationship exhibited by the Y ₂ O ₂ S: Eu _0.08 , Ti _0.0005 phosphor, and conversely, the value of B ₁ A ₂ /A ₁ B ₂ is greater than 1 means the opposite.

As is clear from Figure 2, the sublinearity of the current density-emission brightness relationship exhibited by the Y ₂ O ₂ S: Eu _0.08 , Ti _0.0005 , Ca _z phosphor depends on the amount of Ca coactivation. Change. Also, as is clear from Figure 2, Y ₂ O ₂ S: Eu _0.08 ,
Current density exhibited by Ti _0.0005 , Ca _z phosphor −
Sublinearity related to luminescence brightness occurs when the Ca co-activation amount z value is in the range of 2×10 ^-6 ≦z≦6×10 ^-2
Y ₂ O ₂ S: Eu _0.08 , Ti _0.0005 This is higher than the sublinearity of the relationship between current density and luminance shown by the phosphor. This is effective when the Ti coactivation amount (y value) is in the range of 5×10 ⁻⁶ ≦y≦5×10 ⁻² . In the present invention, the y value is set to 5×10 ^-6 ≦y≦5×
10 ^-2 and the z value were defined in the range of 2×10 ⁻⁶ ≦z≦6×10 ⁻² based on such knowledge. Especially when the z value is in the range of 5×10 ^-5 ≦z≦2×10 ^-2 , Y ₂ O ₂ S: Eu _0.08 , Ti _y , Ca _z phosphors have a current density-emission luminance relationship with high sublinearity. shows.

Note that Figures 1 and 2 show data when the rare earth element Ln constituting the base is Y, the co-activating element M is Ti, and the co-activating element M' is Ca. Results similar to those in FIGS. 1 and 2 were also obtained when Ln was Gd, La, or Lu, and when Ln was two or more of Y, Gd, La, and Lu. Similarly, results similar to those in FIGS. 1 and 2 were obtained when M was Sn and when M was two types, Ti and Sn. Furthermore,
Results similar to those in FIGS. 1 and 2 were obtained when M' was Ce and when M' was two types, Ca and Ce.

In the present invention, the Eu activation amount (x value) is defined in the range of 2×10 ⁻⁴ ≦x≦0.18 from the viewpoint of luminance. The phosphor of the present invention whose x value is within the above range is x
It emits yellow to red light in response to changes in value. In particular, a phosphor having an x value in the range of 2×10 ⁻² ≦x≦0.16 emits red light with good color purity. Note that the amount of Eu has almost no effect on the sublinearity of the current density-emission brightness relationship exhibited by the phosphor.
Furthermore, M (M is at least one of titanium and tin) and M'(M' is at least one of calcium and cerium) have little effect on the emission spectrum (emission color) of the phosphor. That is, the emission spectrum of the phosphor of the present invention is almost the same as that of the Ln ₂ O ₂ S:Eu phosphor with the same amount of Eu activation.

As explained above, according to the present invention, a phosphor that exhibits a good and stable sublinear current density-emission luminance relationship when the current density of the stimulating electron beam increases is obtained. Of the phosphors of the present invention, especially Eu
A phosphor with an activation amount x value in the range of 2×10 ^-2 ≦x≦0.16 emits red light with good color purity, and therefore contains at least one metal from the above-mentioned iron, cobalt, and nickel. ZnS: Contains Cu, Al green light emitting phosphor or at least one metal selected from the above iron, cobalt and nickel (Zn,
Cd) S:Ag is suitable for forming a phosphor film of a current-modulated multicolor cathode ray tube in combination with a blue-green to green-emitting phosphor (all of which exhibit a superlinear current density-emission brightness relationship). Furthermore, the phosphor of the present invention can also be used in electron beam excitation display tubes other than the above-mentioned current modulated multicolor cathode ray tube.

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

Example 1: Yttrium oxide Y ₂ O ₃ 225.8g Europium oxide Eu ₂ O ₃ 14.1g Titanium oxide TiO ₂ 0.04g Sulfur S 120g Sodium carbonate Na ₂ CO ₃ 80g Potassium phosphate K ₃ PO ₄・3H ₂ O 20g Calcium carbonate CaCO ₃ 0.5g Thoroughly mix each of the above phosphor raw materials, fill the resulting mixture into an aluminum crucible, and heat to 1200℃ in air.
It was baked at a temperature of 2 hours. After firing, the obtained fired product was thoroughly washed with water and dried. In this way, a Y ₂ O ₂ S: Eu _0.08 , Ti _0.0005 , Ca _0.005 phosphor was obtained. When the current density of the stimulating electron beam increases, this phosphor exhibits a sublinear current density-emission brightness relationship, and as shown in Figures 1 and 2, the sublinearity of the current density-emission brightness relationship is Y ₂ O ₂ S: higher than Eu _0.08 , Ti _0.0005 phosphor.

Example 2: Yttrium oxide Y ₂ O ₃ 225.8g Europium oxide Eu ₂ O ₃ 10.6g Titanium sulfate Ti(SO ₄ ) ₂ 1.2g Cerium nitrate Ce((NO ₃ ) ₃・6H ₂ O 0.0087g Calcium carbonate CaCO ₃ 0.05 g Sulfur S 120g Sodium carbonate Na ₂ CO ₃ 80g Potassium phosphate K ₃ PO ₄・3H ₂ O 20g In the same manner as in Example 1 using each of the above phosphor raw materials.
_Y2O2S : _Eu0.06 , _Ti0.005 , _{Ce0.00002 , Ca0.0005} phosphor was obtained. When the current density of the stimulating electron beam increases, this phosphor exhibits a sublinear current density-emission brightness relationship, and the sublinearity of the current density-emission brightness relationship is Y ₂ O ₂ S: Eu _0.06 , Ti _0.005 fluorescence. It was taller than my body.

Example 3: Yttrium oxide Y ₂ O ₃ 225.8g Europium oxide Eu ₂ O ₃ 17.6g Tin oxide SnO ₂ 0.03g Calcium nitrate Ca(NO ₃ ) ₂・4H ₂ O 0.24g Sulfur S 120g Sodium carbonate Na ₂ CO ₃ 80g Potassium phosphate K ₃ PO ₄・3H ₂ O 20g In the same manner as in Example 1 using each of the above phosphor raw materials.
Y ₂ O ₂ S: Eu _0.1 , Sn _0.0002 , Ca _0.001 phosphor was obtained.
When the current density of the stimulating electron beam increases, this phosphor exhibits a sublinear current density-emission brightness relationship, and the sublinearity of the current density-emission brightness relationship is Y ₂ O ₂ S: Eu _0.1 , Sn _0.0002 fluorescence It was taller than my body.

[Brief explanation of the drawing]

FIG. 1 is a graph illustrating the sublinear current density-emission brightness relationship exhibited by the phosphor of the present invention. FIG. 2 is a graph illustrating the relationship between the Ca coactivation amount of the phosphor of the present invention and the sublinearity of the current density-emission luminance relationship exhibited by this phosphor. FIG. 3 is a graph illustrating the slightly sublinear current density-emission brightness relationship exhibited by the Ln ₂ O ₂ S:Eu phosphor.

Claims (1)

[Claims] 1 Compositional formula Ln ₂ O ₂ S: Eu _x M _y M′ _z (However, Ln is yttrium, gadolinium,
At least one of lanthanum and lutetium
M is at least one of titanium and tin, M' is at least one of calcium and cerium, and x, y and z are each 2×10 ^-4 ≦x≦0.18 ,5× ^10-6
≦y≦5×10 ^-2 and 2×10 ^-6 ≦z≦6×10 ^-2 ) When the current density of the stimulating electron beam increases, the sublinear current density − Rare earth phosphor showing luminance relationship. 2. The phosphor according to claim 1, wherein z is a number satisfying the following condition: 5×10 ⁻⁵ ≦z≦2×10 ⁻² . 3. Claim 1, wherein x is a number that satisfies the condition 2×10 ^-2 ≦x≦0.16
The phosphor according to item 1 or 2.