JPS5817189A - Fluorescent material for current modulation type multicolor cathode ray tube - Google Patents

Abstract

PURPOSE:The titled fluorescent material presenting a sufficient sublinear current density/luminance relationship when the current density of an exciting beam increases, which comprises a specified Eu/Ce-activated rare earth oxysulfide fluorescent material. CONSTITUTION:Mixed oxides consisting of one compd. selected from among Y2O3, Gd2O3, La2O3, Lu2O3, etc., a Eu compd. such as Eu2O3 and a Ce compd. such as CeO2 are mixed with 30-60wt% S and 5-50wt% flux such as Na2CO3, each based on the mixed oxides, charged in a heat-resistant vessel and baked in air at 900-1,500 deg.C for 0.5-5hr to obtain a rare earth fluorescent material of the formula (wherein Ln is Y, Gd, La or Lu; 10<-4=x<=9X10<-2>; 10<-6=y<=2X10<-3>) presenting a sublinear current density/laminance relationship. USE:A current modulation type multicolor cathode ray tube, etc.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a phosphor for a multicolor cathode ray tube. More specifically, the present invention relates to a current-modulated multicolor cathode ray tube phosphor that exhibits a sublinear current density-emission brightness relationship as the current density of a stimulating electron beam increases.

Recently, multicolor cathode ray tubes have come into practical use as terminal display devices for computers, display devices for aircraft control systems, and the like. This multicolor cathode ray tube uses 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 fluorescent film made up of two types of phosphors that emit light in different colors. This allows for multi-color display.

The multicast cathode ray tubes are classified into two types depending on the method of changing the energy of the stimulating electron beam. In other words, there are two types: one that changes the energy of the stimulating electron beam by changing the accelerating voltage, and the other that changes the energy of the stimulating electron beam by changing the current density.The former is called a voltage modulated multicolor cathode ray tube. , the latter is called a current-modulated multicolor cathode ray tube. For example, regarding voltage modulated multicolor cathode ray tubes, "Nikkei Electronics J1
Pages 106 to 117 of the July 2, 1973 issue, for information on current-modulated multicolor cathode ray tubes,
Publication No. 25? Please refer.

Current-modulated multicolor cathode ray tubes have the advantage that the electron gun structure, electron gun control circuit, etc. are significantly simpler than voltage modulation 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 is a phosphor suitable for use in current-modulated multicolor cathode ray tubes, that is, a phosphor that exhibits a sufficiently superlinear or sublinear current density-emission brightness relationship as the current density of the stimulating electron beam increases. This is because it is not well known.

Conventionally, phosphors that exhibit a super-linear current density-emission brightness relationship when the current density of a stimulating electron beam increases have been made of copper and phosphors containing an appropriate amount of at least one metal selected from iron, cobalt, nickel, and vanadium. Aluminum activated zinc sulfide green emitting phosphor (ZnS:1::u
Silver-activated zinc cadmium sulfide green-blue to red-emitting phosphors [(Zn,Cd)S: It is well known that this phosphor emits green to red light in response to changes in the molar ratio of ZnS and CdS].Also, as the current density of the stimulating electron beam increases, sublinear A manganese-activated zinc silicate green-emitting phosphor (Zn2Sin4: Mn) is known as a phosphor that exhibits a current density-emission brightness relationship.

In multicolor cathode ray tubes, in order to widen the range of change in color, generally i) a red emitting phosphor exhibiting a superlinear excitation energy-emission brightness relationship and a green emitting phosphor exhibiting a sublinear excitation energy-emission brightness relationship; A combination with a phosphor, or i) a combination of a green-blue to green-emitting phosphor that exhibits a superlinear excitation energy-emission brightness relationship and a red-emitting phosphor that exhibits a sublinear excitation energy-emission brightness relationship. The fluorescent film is composed of: From this point of view, in current modulated multicolor cathode ray tubes, the above-mentioned iron,
(ZnyCd)S containing at least one metal among cobalt, nickel and vanadium:
A combination of an Ag red-emitting phosphor (which exhibits a superlinear current density-emission brightness relationship) and the above-mentioned Zn25in4:Mn green-emitting phosphor (which exhibits a sublinear current density-emission brightness relationship) is being considered. contains at least one metal selected from the group consisting of iron, cobalt, nickel and vanadium; (Z
n, Cd) S:Ag A red-emitting phosphor exhibiting a sublinear current density-emission brightness relationship to be combined with a green-blue to green-emitting phosphor (both exhibiting a superlinear current density-emission brightness relationship) was previously completely unknown. Therefore, there is a strong need for a red light-emitting phosphor that exhibits a sufficiently sublinear current density-emission brightness relationship as the current density of the stimulating electron beam increases.

The present invention was made under the above-mentioned circumstances, and provides a current-modulated multicolor cathode ray tube phosphor that exhibits a sufficiently sublinear current density-emission brightness relationship when the current density of a stimulating electron beam increases. , in particular a red-emitting phosphor.

Composition formula (% formula %) (However, Ln is a small amount (all of them are one type) of yttrium, gadolinium, lanthanum, and lutetium. The europium-activated rare earth oxysulfide phosphor is activated by Eu under electron beam excitation. It is well known that Y emits high-intensity yellow to red light in response to changes in the amount of Eu.For example, Y
20□S:Eu phosphor is currently in practical use as a phosphor for the red light emitting component of color television cathode ray tubes.

(&,Eu)20□S phosphor is known to exhibit a very slightly sublinear current density-emission brightness relationship as the current density of the stimulating electron beam increases, as illustrated in Figure 1. .

Since the (Ln,Eu)20□S phosphor emits light at a high luminance at a practical level, the present inventors have developed a K (Ln,Eu)202S phosphor to achieve the above object of the present invention. current density - amount of luminance cerium (Ce) v
Ha (Ln, Eu) 202S when using a specific range of amount
It has been discovered that the sublinearity of the current density-emission brightness relationship exhibited by the phosphor can be increased, and that the sublinearity is significantly high in a specific range within this Ce coactivation amount range, The present invention has now been completed.

The compositional formula of the current modulated multicolor cathode ray tube phosphor of the present invention is (Lnl-x-y y E"x T Ce y) 2
o□s (Ln is yttrium, gadolinium,
at least one of lanthanum and lutetium, and X and y are respectively 10≦X≦9×10− and 10−6≦
It is a europium- and cerium-activated rare earth oxysulfide phosphor expressed as follows: y≦2Xlo-3. When the current density of the stimulating electron beam increases, this phosphor exhibits a current density-emission brightness relationship with higher sublinearity than the (Ln, Eu)202S phosphor, especially when the Ce coactivation amount y The value is 2
A phosphor in the range of 10'-'≦y≦10-3 exhibits a current density-emission brightness relationship with extremely high sublinearity.

Japanese Patent Publication No. 47-3321 and Japanese Patent Publication No. 47-3322 contain the composition formula % (where M' is yttrium, gadolinium, or lanthanum, M is a lanthanide element with at least %111, and
A lanthanide element-activated rare earth oxysulfide phosphor is disclosed. A portion of the phosphor of the present invention is included in this lanthanide element-activated rare earth oxysulfide phosphor. However, in the above-mentioned publication, the phosphors that use Eu f activator and Ce' as co-activator are not listed, and even more so, Eu and Ce' fzt are not listed as activators and co-activators, respectively. The phosphor used in a specific range of amounts as shown in FIG. is not suggested at all.

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

First, as raw materials for the phosphor, i) a first compound group consisting of yttrium oxide (Y2O3), gadolinium oxide (Gd203), lanthanum oxide (La203), and lutetium oxide (Lu203);
and a second group of compounds consisting of yttrium compounds, gadolinium compounds, lanthanum compounds and lutetium compounds that can be easily converted into Y2O3, Gd2O3, La2O3 and Lu2O3 at high temperatures, such as nitrates, sulfates, carbonates, oxalates, hydroxides, etc. at least one compound selected from the group of compounds; ii) europium oxide (Eu203) and nitrate;
Sulfates, carbonates, oxalates, hydroxides, etc. are easily oxidized at high temperatures.
at least one compound selected from the group of compounds consisting of europium compounds that can be converted into u2O, Sulfur (S), and V) sodium carbonate (Na2CO3), potassium phosphate (
Fluxing agents such as alkali metal salts commonly used in the production of oxysulfide phosphors such as K3PO4) are used. i above
) and lv) are base raw materials, the above i) is a Eu activator raw material, and the above m) is a Ce coactivator raw material. The above i), h) and ii) are stoichiometrically represented by the composition formula %
(Formula %) (However, Ln is one of yttrium, gadolinium, lanthanum, and lutetium, and X and y are 10-'≦X≦9X10" and 1O-, respectively.
6≦y≦2×10-3 (a number satisfying the condition: 6≦y≦2×10−3). The above iy) is 30 to 60% of the above mixed oxide.
% by weight, and the overlay is used in an amount corresponding to 5 to 50 weight % of the mixed oxide. Weigh the required amount of each phosphor raw material and mix thoroughly to form a phosphor raw material mixture. obtain.

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 is carried out in air at a temperature of 900 to 1500°C. The firing temperature 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 sublinearity of the current density-emission brightness relationship exhibited by the Eu activation amount (Ln, Eu)20□S phosphor. Higher than linearity.

FIG. 2 is a graph illustrating the current density-emission brightness relationship exhibited by the phosphor of the present invention, (YO, 9499
91EuO005lCe0,00001) This shows the current density-emission brightness relationship exhibited by the 202S phosphor. In FIG. 2, the luminance on the vertical axis is expressed by the Kitami luminance, which is the luminance of the (Yo, 951E'0.05) 202s phosphor at each current density value, 'I\:100q6.

The following can be understood from the WJ2 diagram.

That is, (Yo, 95 # EuO, 05) 202
As shown in Figure 1, the S phosphor shows a slightly sublinear current density-emission brightness relationship, so it is clear that the K
(YO,94999z ”uo,os s CEO,o
ooot) The 202S phosphor shows a sublinear current density-emission brightness relationship, and the sublinearity of the current density-emission brightness relationship is the same for the Eu activation amount (YO0951Euo, .5) 20□S phosphor. This is higher than the sublinearity of the current density-emission brightness relationship shown by .

The sublinearity of the current density-emission brightness relationship exhibited by the phosphor of the present invention is a function of the amount of Ce coactivation (y value). For example, if the current density of the stimulating electron beam is 0.1
μA/cII? and 2, (YO,95-ysEuo,os,Cey)20□ when OμA/cm2
Letting the luminance of the S phosphor be A□ and B, respectively, the sublinearity of the current density-emission luminance relationship exhibited by this phosphor is expressed as B1/A1 (of course, the values of B and /A1 are The smaller the value, the higher the sublinearity), and this sublinearity changes depending on the amount of Ce coactivation.

Figure 3 is (YO,95-y jEuO0O5ICey
) is a graph showing the relationship between the Ce coactivation amount of a 202S phosphor and the sublinearity of the current density-emission brightness relationship exhibited by this phosphor. In Fig. 3, the vertical axis representing sublinearity is B, A2/AlB2.
It is shown by the value of Here, A2 and B2 are respectively (Yo, 9+, -7, Euo, o5.Cey) 20□
The amount of Eu activation is the same as that of the S phosphor (YO, 95#Eu
O,05) Current density of 202S phosphor 0.1 μA /
Emission brightness in cm2 and 2, O/JA/cm2. The fact that the value of B1A2/AlB2 is smaller than 1 means that (Yo, v, -, #E"o, os,
(:eρ20□S The sublinearity of the current density-emission brightness relationship shown by the phosphor is (YO,% t”0,
05) means higher than the sublinearity of the current density-emission brightness relationship exhibited by the 202S phosphor,
Conversely, a value of B1A2/AlB2 greater than 1 means the opposite.

As is clear from FIG.
The sublinearity related to luminance changes depending on the amount of Ce coactivation. Also, as is clear from Figure 3, (YO
,95-y #EuO,05,Ce, ) The sublinearity of the current density-emission brightness relationship exhibited by the 2028 phosphor is such that the Ce co-activation amount y value is lC≦y≦2 X 1
When it is in the range of 0-', (Y(1, B6 zEu
o. 5) Higher than the sublinearity of the current density-emission brightness relationship exhibited by the 202S phosphor. It is based on this knowledge that the y value is defined in the range of '&10''≦y≦2×10-3 in the present invention.

When the %JICI value is in the range of 2×10-6≦y≦1O-3 (y, , =, .

Eu, 05. The Ce, )20□S phosphor appears to exhibit a current density-emission brightness relationship with extremely high sublinearity.

Figure 4 shows (Y, Eu, Ce) 0.95-y O,05y 2 2Ce of the OS phosphor.
It is a graph showing the relationship between the amount of coactivation and the luminance of this phosphor. In Figure 4, the vertical axis representing luminance is y=Q
A phosphor that is (YO,951EuO,05)
The luminance of the 202S phosphor is expressed as a relative value of 2ioo%.The luminance shown in Figure 4 is the luminance when the current density of the stimulating electron beam is 0.5μA/crrL2. be.

As is clear from FIG. 4, as the amount of coactivation of C and e increases, the luminance of light emission gradually decreases.

Therefore, Ce has only a negative effect on the luminance of the phosphor of the present invention. However, the phosphor of the present invention, which has a small Ce coactivation amount y value, maintains sufficiently high luminance.

Furthermore, Figures 2 to 4 show rare earth elements constituting the matrix.
This is data when n is Y, but Ln is Gd,
When La or Lu and Ln are Y, G
d, La, and Lu, the same results as in FIGS. 2 to 4 were obtained.

In the present invention, the Eu activation amount (X value) is defined in the range of 10-4≦X≦9×10''-2 from the viewpoint of luminance, etc. The firefly of the present invention whose X value is within the above range The light body emits yellow to red light in response to changes in the X value.Especially when the X value is #
A phosphor in the range of 10-''≦X≦8×10''-2 emits red light with good color purity. Note that gu has almost no effect on the sublinearity of the current density-emission brightness relationship exhibited by the phosphor.

In addition, Ce has almost no effect on the emission spectrum (emission υ) of the phosphor. That is, the emission spectrum of the phosphor of the present invention has the same amount of Eu activation (Ln, Eu
) The emission spectrum is almost the same as that of the 20□S phosphor.

As explained above, the present invention provides a sublinear current density-emission brightness relationship when the current density of stimulating electron beams increases. The present invention provides a current-modulated multicolor cathode ray tube phosphor shown in the figure. Among the phosphors of the present invention, those having an Eu activation amount X value in the range of io''-''≦X≦8X10-2 emit red light with good color purity. ZnS:Cu, AJ green emitting phosphor containing at least one metal of iron, cobalt, nickel and vanadium or less of the above iron, cobalt, nickel and vanadium (all containing at least one metal). Zn, Cd) S:Ag Suitable for constructing a phosphor film of a current-modulated multicolor cathode ray tube in combination with a green-blue to green-emitting phosphor (all of which exhibit a superlinear current density-emission brightness relationship) It is.

Next, the present invention will be explained by examples.

Example 1゜Yttrium oxide Y2O3214,5, lit europium oxide Eu2O,17,69 cerium oxide A
CeO20-00341 Sulfur S
120, li+sodium carbonate Na2Co3809 potassium phosphate K3PO4・3
3H2O20 The above phosphor raw materials were thoroughly mixed, the resulting mixture was filled into an alumina crucible, and heated in air for 1200 m
It was baked for 2 hours at a temperature of °C. After firing, the obtained fired product was thoroughly washed with water and dried. In this way (Yo,
949+is p Euo, os t CEO, ooo
ot) 202S phosphor Z 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 Figure 3, the sublinearity of the current density-emission brightness relationship is (YO
095? EuO,05)202S phosphor.

Example 2゜Yttrium oxide Y2O3219,09Europium oxide E”203 10.69Cerium nitrate Ce(NO3)3.61-1.!OO,0087
，! i' sulfur S
1209 Sodium carbonate Na2CO380g Potassium phosphate K3PO4.3H2020g In the same manner as in Example 1 using each of the above phosphor raw materials (YO196999
tEuO,03# CeO,OO[K11) 20
A 2S 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 (YO, 9
71E”0.03) was higher than that of the 2o2s phosphor.

Example 3 Yttrium oxide Y2O3158,0g Gadolinium oxide Gd2O379,8g Europium oxide
Eu2O328,2g Cerium oxide CeO□0.034
g Sulfur S 120
9 Sodium carbonate Na2CO3 1809 Potassium phosphate K3PO4.3H20209 Using each of the above phosphor raw materials, the same procedure as in Example 1 was carried out (YG, 6999 #GdO
,22tEuo,oa jCeOooool) 20
2" 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 (Yo, , ,Gd,,.

It was higher than that of EuO,011)2o□S phosphor.

[Brief explanation of drawings]

FIG. 1 is a graph illustrating the slightly sublinear current density-emission brightness relationship exhibited by a (Ln,Eu)20□S phosphor. FIG. FIG. 3 is a graph illustrating a sublinear current density-emission brightness relationship. FIG. This is a graph illustrating the relationship. FIG. 4 is a graph illustrating the relationship between the amount of Ce coactivation of the phosphor of the present invention and the luminance of this phosphor. FIG. degree (J”/crn') (Voluntary) Procedural amendment 1. Indication of case 1982 Patent Application No. 115663 2, Name of invention Relationship with case Patent applicant 4 No agent 6, Increased by amendment Number of inventions None 7, “Title of the invention”, “Claims” and “Claims” of the specification subject to amendment
2) "Detailed Description of the Invention" column 2) "Claims" should be corrected as shown in the attached sheet. 3) Delete "For multicolor cathode ray tube" in the second line of page 3 of the specification. 4) Delete lines 5 to 6 on page 3, lines 3 to 4 on page 8, lines 16 to 17 on page 9, and lines 19 to last on page 19, "For current modulated multicolor cathode ray tubes." . 5) "Cobalt," in lines 11 and 15 of page 5, last line of page 6, and lines 7 and 10 of page 7, is corrected to "cobalt and." 6) Delete "and vanadium" in lines 12 and 16 of page 5, from the last line of page 6 to line 1 of page 7, lines 7-8 and line 10 of page 7. 7) Correct the phrase "indicates and is therefore useful" in lines 11-12 on page 11 to "indicate". 8) Insert the following sentence after "Suitable." on page 20, line 13. [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. ” Claim (1) Composition formula % Formula % At least one of lanthanum and lutetium, and X and y are 10″≦X≦9×10 and 10−6≦y≦2, respectively
A rare earth phosphor that exhibits a sublinear current density-emission brightness relationship as the current density of a stimulating electron beam increases. (2) Claim 1, characterized in that the above y is a number that satisfies the following condition: 2×10≦y≦10
Fluorescent substance described in Section 2. (3) The above X is 10-2≦X≦8
The firefly or light body according to claim 1 or 2, characterized in that the number satisfies the following conditions.

Claims (3)

[Claims] (1) Composition formula % formula %) (However, Ln is one of yttrium, gadolinium, lanthanum, and lutetium, and X and y are 10-4≦X≦9X10-2 and 1, respectively.
0 ≦ y ≦ 2 × 10) When the current density of the stimulating electron beam increases, a sublinear current density-emission brightness relationship is observed. body. (2) The phosphor according to claim 1, wherein y is a number satisfying the condition: 2 x 10'-'≦y≦10-3. (3) The phosphor according to claim 1 or 2, wherein the above-mentioned X is a number satisfying the following condition: 10-2≦X≦8×10-”.