JPS5828160A - Current-modulating-type multicolor braun tube - Google Patents

Abstract

PURPOSE:To increase the variation in display colors of a current-modulating Braun multicolor tube by using an yellow to red color emitting rare-earth-element oxysulfide activated with Eu and Ce as a phosphor which has a sublinear relationship between the current density and the emission luminance. CONSTITUTION:In a multicolor Braun tube in which the entire a fluorescent film is excited by polarizing an electron beam sent from a current modulating electron gun so as to make the above fluorescent film to emit light, a phosphor which has a sublinear relationship between its current density and its coloring luminance is used. As the above phosphor, a yellow to red color emitting rare- earth-element oxysulfide phosphor activated with Eu and Ce, which is represented by a compositional formula of (Ln1-x-y, Eux, Cey)2O2S, is used. In the above formula, Ln represents one element chosen from among Y, Ga, La and Lu, and x and y should satisfy the relationships of 10<-4=x<=9X10<-2> and 10<-6=y<=2X10<-3>. A current modulating multicolor Braun tube having a fluorescent film prepared by use of the above phosphor has a wide variety in its display colors, and is highly valued for its technical use.

Description

DETAILED DESCRIPTION OF THE INVENTION More specifically, the present invention relates to a current modulated multicolor cathode ray tube.

Recently, multicolor cathode ray tubes have come into practical use in display devices such as computers. This multicolor cathode ray tube has a phosphor that exhibits a superlinear or near-linear excitation energy-emission brightness relationship when the energy of the stimulating electron beam is applied, and a sublinear or near-linear relationship when the energy of the stimulating electron beam increases. It is a cathode ray tube that has a phosphor film composed of two types of phosphors that emit light in different colors, and a phosphor that exhibits an excitation energy-emission brightness relationship (however, both of the above two types of phosphors are linear). (It is not a phosphor that exhibits an excitation energy-emission brightness relationship), but by changing the energy of the beam, the emitted color of the phosphor film is changed, thereby producing a multicolor display. Multicolor cathode ray tubes do not attempt to reproduce natural colors like color cathode ray tubes for televisions (they simply aim to increase the degree of discrimination of displayed images through color changes, so their phosphor film does not need to be patterned like color television tubes. Therefore, while the resolution of color television tubes is determined by the pattern of the phosphor, the resolution of multicolor tubes is determined by the stimulation electron beam. Because of this, multicolor CRTs generally have higher resolution than color television tubes.This high resolution multicolor display makes multicolor CRTs suitable for character and graphic displays. This is because it is possible.

The above 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, one changes the energy of the stimulating electron beam by changing the accelerating voltage, and the other 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. When comparing voltage modulated multicolor cathode ray tubes and current modulated multicolor cathode ray tubes, current modulated multicolor cathode ray tubes have the advantage of being significantly simpler in terms of circuitry than voltage modulated multicolor cathode ray tubes.

FIG. 1 is a schematic sectional view of a typical example of a current modulation type multicolor cathode ray tube, and is used to explain the structure of a current f modulation type multicolor cathode ray tube. As shown in FIG. 1, an electron gun 1 is provided within a cylindrical portion of a glass funnel 7 which together with a glass face plate 6 constitutes a bulb. This electron gun 1 is a so-called current modulation electron gun which has a function of changing the flow density of the electron beam 2 emitted from it. A fluorescent film 3 is provided on the inner surface of the glass face plate 6 so as to face the current modulated electron gun 1. Further, a pair of deflection coils 4, 4' are provided between the current modulation electron gun 1 and the fluorescent film 30, that is, at the neck portion of the glass funnel 7.
4' is for creating a magnetic field perpendicular to the traveling direction of the electron beam 2 to deflect the electron beam 2. The entire surface of the fluorescent film 3 is excited by the electron beam 2 emitted from the current modulated electron gun 1 and deflected by the deflection coil 4.4', and emits light.

As explained above, the phosphor film 3 includes a phosphor that provides a super-linear or near-linear current density-emission brightness relationship when the current density of the electron beam 2 increases, and
When the current density increases, sublinear or linear
It is a non-patterned phosphor film consisting of two types of phosphors that exhibit a linear current n-emission brightness relationship and a phosphor that emits light in different colors. (It is not a phosphor that exhibits a current density-emission brightness relationship.) This non-patterned phosphor film 3 may be a film with a two-layer structure in which the above-mentioned two types of phosphors constitute separate layers, or it may be a mixed phosphor film in which the above-mentioned two types of phosphors are mixed. It may be a single-layer film made of a phosphor (in FIG. 1, the non-patterned fluorescent film 3 is depicted as a single-layer film). The non-patterned fluorescent film 3 is excited by the electron beam 2 and emits light.
Since it is composed of two types of phosphors as described above, its luminescent color changes in response to changes in the current density of the electron beam 2. Therefore, by changing the current density of the electron beam 2, the display image observed through the glass face plate 6 can be made into a multicolor image whose colors change in accordance with the change in the current density of the electron beam 2.

Back side of non-patterned fluorescent film 3 (glass face plate 6
A thin film (metal back) 5 made of metal such as aluminum is provided on the side opposite to the electron gun 1 (the side closer to the electron gun 1). The metal thin film 5 reflects the light emitted from the fluorescent film 3 toward the inside of the cathode ray tube, thereby passing the light through the glass face plate 6. It is provided for the purpose of increasing the brightness of a multicolor display image observed by
It is not essential for current modulated multicolor cathode ray tubes.

Note that current-modulated multicolor cathode ray tubes generally have a
As shown in the figure, it has one current modulation electron gun,
A current-modulated multicolor cathode ray tube having a plurality of current-modulated electron guns is also known.

As mentioned above, the current modulation type multicolor cathode ray tube having the structure as explained above with reference to FIG. Despite this, the practical application of current-modulated multicolor cathode ray tubes has been much slower than that of 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.

The composition formula (%) (where Ln is at least one of yttrium, gadolinium, lanthanum, and lutetium) It is well known that in response to changes, high-intensity yellow to red light is emitted. For example, Yz is one of these phosphors and has a relatively large amount of Eu activation.
The OzS:Eu fluorophore is currently in practical use as a phosphor for the red light-emitting component of color cathode ray tubes for televisions. Moreover, this (Ln, Ell) 2028 phosphor exhibits a sublinear current density - when the current density of the stimulating electron beam increases.
It is known that the relationship between luminance and luminance is shown. Therefore, (L
n, Eu) Z02S phosphor becomes super IJ near- or near-near when the current density of the stimulating electron beam increases.
It shows the current density-t MIIj relationship, and this (1, n
, Eu) 2028 phosphor can be used in the phosphor film of a current-modulated multicolor cathode ray tube in combination with a phosphor having a different color from that of the phosphor, especially a blue to green emitting phosphor.

The above (Ln, Eu) 2028 phosphor is the best of the few currently known phosphors that exhibit a sublinear current density-emission brightness relationship. However, the sub-IJ nearness of the current density-emission luminance relationship of the (Ln, Bu)202S phosphor is not sufficiently bright, and for this reason, (Ln,l:u)2(J
The range of change in display color of a current modulated multi-color cathode ray tube having a fluorescent film using zS fluorescent light is not yet satisfactory for practical purposes. Therefore, (Ln, Eu) 2
028 (Ln, Eu)20)2S instead of fluorophore
It has a fluorescent film using a yellow to red light-emitting phosphor that has a higher sublinearity in the current density-emission brightness relationship than the fluorescent material, and it has a fluorescent film using a (Ln, Eu) 202S phosphor. A current-modulated multi-color cathode ray tube with a wider range of display color change than a current-modulated multi-color cathode ray tube is desired.

The present invention was made under the above-mentioned circumstances, and its overall purpose is to provide a current modulation type multicolor cathode ray tube having a novel fluorescent film and having a wide range of display color changes. be.

More specifically, the present invention provides the above (Ln, Eu) 20
It has a phosphor film using a yellow to red light-emitting phosphor that has a higher sublinearity in the current density-emission brightness relationship than the No. 28 phosphor. (Ln, Eu) Current modulation type with a fluorescent film using zOzz phosphor ゛The purpose is to provide a current modulation type multicolor cathode ray tube with a wider range of display color change than a multicolor cathode ray tube. It is something.

The above purpose is such that the compositional formula is (Ln, EuX, Ce, )20281-
X-3/ (However, Ln is at least one of yttrium, gadolinium, lanthanum, and lutetium, and each of X and y is 1O
-4≦X≦9X10" and 10≦y≦2 This is achieved by using the fluorescent material as a phosphor that exhibits a sublinear current density-emission brightness relationship constituting a fluorescent film.

That is, the current modulated multicolor cathode ray tube of the present invention includes at least one current modulated electron gun having a function of changing the current density emitted from the current modulated electron gun, and a direction in which the electron beam travels so as to face the current modulated electron gun. A non-patterned phosphor film installed on the substrate and a magnetic field perpendicular to the traveling direction of the electron beam are applied to deflect the electron beam so that the entire surface of the non-patterned phosphor film is excited by the electron beam. a phosphor comprising a deflection coil for emitting light, wherein the non-patterned phosphor film exhibits a sublinear current density-emission brightness relationship as the current density of the electron beam increases; have different emitting colors,
When the current density of the electron beam increases, in a current modulating multi-color plow/tube consisting of a phosphor that exhibits a superlinear or more linear current density-emission brightness relationship, the above-mentioned sublinear current density-emission brightness relationship is achieved. A phosphor exhibiting the composition formula %) ) (where Ln is at least one of yttrium, gadolinium, lanthanum, and lutetium, and X and y are each JO-4≦X≦9 - and 1
It is characterized by being composed of a europium and cerium activated rare earth oxysulfide yellow to red light-emitting phosphor represented by the following formula: 0≦y≦2×10.

Patent Application No. 56-115663 (
As detailed in the above (Ln Eu. filed July 23, 1981).

'''-Ys
By further activating the 2028 fluorophore with Ce f (Ln.

Eu)20zs phosphor has improved sublinearity in the current density-emission brightness relationship, and
) Shows a current density-emission brightness relationship with higher sublinearity than that of the 202S phosphor. Therefore, (Ln,
Eu Ce) 1-X-yt using 2028 fluorophore
The current-modulated multi-color CRT of the present invention having a fluorescent film of X, y has a wider range of color change than the current-modulated multi-color CRT of the present invention having a fluorescent film using (Ln, Eu)zOzz phosphors. is wide.

The present invention will be explained in detail below.

In the current modulated multi-color cathode ray tube of the present invention, the sub-IJ constituting the phosphor film has the above-mentioned (Ln Eu
Ce) 2028 phosphor used 1-X-yr
+ 'J, but the sublinearity of the current density-emission brightness relationship exhibited by this phosphor is a function of the amount of Ce coactivation (y value). And when the y value 6-3 is in the range of 10≦y≦2×IO (Ln
Eu Ce ) 2028 phosphor is Eu activation amount 1-X
7) '+ x, '/ (y value) shows a current density-emission brightness relationship with higher sublinearity than the (Ln, Eu) 202s phosphor with the same y value. Used in the present invention (Lnr-x-y.

This is because the Ce coactivation y value of the Eu x , Cey ) 202S phosphor is defined in the range of 10≦y≦2×10. Especially when the y value is 2 X l O−'≦
When y≦10, (Ln, −x−y,
EuX.

Ce ) 2028 phosphor exhibits a significantly high current density-emission brightness relationship of sublinearity, and thus has a y value in this range (Ln 1°y , Eu x.

Particular preference is given to using Cey) 202S phosphor.

In addition, the Eu activation amount (X value) of (Ln, -, -, EuX, Ce,) 202s phosphor is 10-4≦ from the viewpoint of luminance etc.
It is defined in the range of X≦9×10. The X value is within the above range (Ln I −X−y , Eu x , Cey )
The 202S phosphor emits yellow to red light in response to changes in the X value. That is, (Ln, X, EuX, Ceρ2
The emission color of the 028 phosphor is a function of the X value. Especially when the X value is in the range of 10-2≦X≦8
n, -X-, Eu It is particularly preferable to use a fluorophore.Eu has almost no effect on the sublinearity of the current density-emission brightness relationship exhibited by the phosphor.Also, Ce has almost no effect on the emission spectrum (emission color) of the phosphor. No effect.

That is, (Lnl-X, , y, EuX, Ceρ2
The emission spectrum of the 02S phosphor is almost the same as that of the (Ln, Eu) 202S phosphor, which has the same amount of ELII activation.

In addition, the above (Ln,, -, EuX, Ce,)z02s02
s Fluorescence is explained in detail in the above-mentioned Japanese Patent Application No. 115663/1982, and the contents of this Japanese Patent Application No. 115663/1982 are cited herein without modification.

On the other hand, the above (Ln 1-x-y, Eux, Cey
') The phosphors constituting the phosphor film of the current modulated multicolor cathode ray tube of the present invention together with the phosphor consisting of the 202S phosphor exhibiting a sublinear current density-emission brightness relationship are as follows:
The luminescent color is different from the above-mentioned phosphor which shows a sublinear current density-emission brightness relationship, and when the current density of the stimulating electron beam increases, it is a phosphor that shows a superlinear or even linear current density-emission brightness relationship. Any phosphor may be used. However, (Ln+ x y.

Ell, Ce, )202s This (Ln r-x y,
Eux.

Ce y ) 202S A phosphor that exhibits a sublinear current density-emission brightness relationship consisting of a phosphor is combined with a phosphor that exhibits a super-linear or near-linear current density-emission brightness relationship that emits blue to green light. It is preferable that the phosphor exhibits the following. A specific example of such a phosphor is a silver-activated phosphor containing an appropriate amount of at least one metal selected from iron, cobalt, nickel, and vanadium, which exhibits a superlinear current density-emission brightness relationship. Zinc cadmium sulfide blue-green to green-emitting phosphor [(Zn
, Cd)S:Ag, the luminescent color of this phosphor is ZnS
A copper- and aluminum-activated zinc sulfide green-emitting phosphor (ZnS :Cu, Ag)
Examples of phosphors showing a linear current density-emission brightness relationship include silver-activated zinc sulfide cadmium blue-green to green-emitting phosphors [(Zn, Cd)S:Ag], copper-activated and aluminum-activated phosphors Zinc sulfide green-emitting phosphor (ZnS
:Cu, All), copper and aluminum activated zinc sulfide cadmium green emitting phosphor ((Zn,Cd)S:C
u, Ae:), terbium activated rare earth oxide green emitting phosphor ((Ln.

Tb) 202S, where Ln is at least one of yttrium, gadolinium, lanthanum, and lutetium], a silver-activated zinc sulfide blue-emitting phosphor (ZnS
:Ag), cerium-activated yttrium silicate blue-emitting phosphor (YzSiOs:Ce), and the like. Among these phosphors, particularly preferred phosphors are (Zn, Cd)S:Ag blue-green to green-emitting phosphors containing at least one metal selected from the group consisting of iron, cobalt and nickel; It is a ZnS:Cu,Al green light-emitting phosphor containing an appropriate amount of at least one metal selected from cobalt and nickel (both exhibit a superlinear current density-emission brightness relationship).

The fluorescent film of the current modulated multicolor cathode ray tube of the present invention (
Non-patterned phosphor film) is ("I X-7+Eu) (, Ce
y) 2028 A phosphor exhibiting a current density-emission brightness relationship of fp') = f- from a phosphor, and a super-linear current that emitted light in a different color from that of this phosphor. The film may have a two-layer structure in which two types of phosphors exhibiting a density-emission brightness relationship constitute separate layers;
Alternatively, it may be a single layer film made of a mixed phosphor in which the above two types of phosphors are mixed in an appropriate ratio. In the former case, the layer closer to the electron gun is (Ln, −x−y,
It is preferable to use a phosphor that exhibits a sublinear current density-emission brightness relationship and is made of a 202S phosphor (EuX, Cey).

In the latter case, the mixed phosphor has (Ln,
It is preferable to use a mixed phosphor to which particles of a phosphor having a sublinear T y current density-emission brightness relationship made of a 02S phosphor are attached.

The phosphor film of the current modulated multicolor cathode ray tube of the present invention is formed by a conventional non-pattern phosphor film manufacturing method such as a precipitation coating method, a spin coating method, or a commercial method. Furthermore, as mentioned earlier, a thin film made of metal such as aluminum is generally provided on the back surface of the fluorescent film (the surface closer to the electron gun), but this metal thin film can be fabricated using conventional metal thin film manufacturing methods such as vapor deposition. It is formed by ゛.

As explained earlier, when the Eu activation amount is the same (Ln 1□-y, Eu x , Cey) 20
The 2S phosphor exhibits the same emission color as the (Ln, Eu) z028 phosphor, and exhibits a current density-emission brightness relationship with higher sublinearity than the (Ln, Eu) 202S phosphor. Therefore, as specifically shown in the following examples, (Ln 1
-x y , Eux , Cey ) 202S phosphor as the phosphor that exhibits the current density-emission brightness relationship of the present invention, the current modulated multicolor cathode ray tube of the present invention has (Lnl-X-5+Eu
x, instead of Ceρ202S fluorophore, this fluorophore and Eu activation amount are the same (Ln, Eu) 202s
The range of change in colors displayed on the remote control is much larger than that of a current-modulated multicolor cathode ray tube with a phosphor film manufactured under the same specifications and conditions, except that the phosphor is used as a phosphor that exhibits a sublinear current density-emission brightness relationship. wide. As described above, the present invention provides a change in display color compared to a current-modulated multicolor brown display having a phosphor film using a (Ln, Eu)zo2s phosphor that exhibits a sublinear current density-emission brightness relationship. The present invention provides a current-modulated multi-color cathode ray tube with a wide range of practical applications, and its industrial utility value is great.

Examples (Yo, 94999, ELlo, 05, CEO,
oooox) 202S red-emitting phosphor and nickel-containing (Zn, Cd)S:Ag green-emitting phosphor (showing a superlinear current density-emission brightness relationship as described above)'i3: A current-modulated multicolor cathode ray tube having the structure shown in Fig. 1 in which a fluorescent film is made of a mixed phosphor mixed at a weight ratio of 2:2 was manufactured according to a conventional manufacturing method for a current-modulated multicolor cathode ray tube. was prepared by the precipitation coating method.

FIG. 2 is a graph showing the change in the emission spectrum corresponding to the increase in the current density of the electron beam of the current-modulated multicolor cathode ray tube of the present invention obtained, with curves a Hb H
C, d'+erf and g are electron beam current densities of 0.1, 0.2, 0.5, 1.0, respectively.
2.0, 3.0 and 4. OtLA/cm! In the case of (electron beam, the acceleration voltage is 25KV in both cases)
) is the emission spectrum of In addition, in Figure 2,
The vertical axis representing the light intensity is (Yo, 94999, Eu o
, os , Ce o, oooot ) 202S It is expressed as a relative value with the emission intensity of the main emission peak of the red-emitting phosphor as 1. As is clear from Fig. 2, as the current density of the electron beam increases (Yo, 911999
, Euo, os, CEO, oooot) 202
The ratio of the emission intensity of the nickel-containing (Zn,Cd)S:Ag green-emitting phosphor to the emission intensity of the S red-emitting phosphor increases, and therefore the emission color of the cathode ray tube increases as the current density of the electron beam increases. changes according to

FIG. 3 is a graph showing on the UcS chromaticity diagram the change in emitted light color as the current density of the electron beam of the current modulated multicolor cathode ray tube of the present invention increases. In Figure 3, the chromaticity point A (u20.3891, v''0.35
68), the current density of the electron beam is 0.1 μA-/c
M is the emission color of the cathode ray tube (the emission spectrum of the cathode ray tube is curve a in Figure 2), and the chromaticity point B (u = 0.1950.v = 0.372)
), the current density of the electron beam is 4.0μA/cA
(The emission spectrum of a cathode ray tube is curve g in Figure 2). As shown in FIG. 3, the emission color of the current modulated multicolor cathode ray tube of the present invention is determined by the current density of the electron beam of 0.1 μA.
When increasing from /cA to 4.0 μh/ctl, it changes from chromaticity point A (red) to chromaticity point B (yellow-green).

In addition, the chromaticity point C (u = 0.2247°V
= 0.3699) is a phosphor showing a sublinear current density-emission brightness relationship (Yo, 94999).
.

Euo, os, CEO, ooool) Instead of the 2028 red gz light phosphor, this phosphor and Eu have the same activation amount and therefore the same emission color (Yo, 95,
The current density of the electron beam of the current modulated multicolor cathode ray tube of the current modulated multicolor cathode ray tube manufactured in exactly the same manner as the above current modulated multicolor cathode ray tube of the present invention except that the 2028 red light emitting phosphor was used was 40 μA/c, fI
represents the emitted color when . This (Yo, 95°Eu
o, os) 2028 The current density of the electron beam of a cathode ray tube using a red-emitting phosphor is 0.1 μA / cr
The emitted light color in the case of 1 is the same as that of the cathode ray tube of the present invention at the same current density, and is expressed by the chromaticity point A. Therefore, the emission color of the cathode ray tube changes from chromaticity point A to chromaticity point C when the current density of the electron beam increases from 0.1 μA/i to 4.0 μA/d.

As is clear from the comparison of the length of the straight line connecting chromaticity point A and chromaticity point B and the length of the straight line connecting chromaticity point A and chromaticity point Ci, the current density of the electron beam is from 0.1 μA/crtl. 4
．． The range of change in emitted light color when increasing to OAA/cJ is higher for the cathode ray tube of the present invention than for the above (Yo, 95,
Euo, os) 2028 wider than a cathode ray tube using red-emitting phosphor. In addition, the range of change in luminescent color is 2"
π2 + , 2, when the current density of the electron beam increases from 0.1 μA/cl to 4.0 μA/d, m of the above-mentioned cathode ray tube of the present invention is 0I95, whereas Above (Yo, 95, Euo', os)
The W of a cathode ray tube using a 202s red-emitting phosphor is 0.165.

[Brief explanation of the drawing]

FIG. 1 is a schematic cross-sectional view of a typical example of a current-modulated multicolor cathode ray tube. FIG. 2 is a graph showing changes in the emission spectrum of an example of the multicolor cathode ray tube of the present invention as the current density of the electron beam increases. Figure 3 shows the change in emitted light color as the electron beam current density increases in an example of the current modulated multi-color cathode ray tube of the present invention, and shows the change in emitted light color as the (Ln, Eu)2028 phosphor is sublinear current density - emitted luminance. It is a graph shown on the UC8 chromaticity diagram in comparison with the change in the emitted light color of a current modulated multicolor cathode ray tube having a phosphor film used as a phosphor, showing the relationship. 1... Current modulation electron gun 2...
...Electron beam 3...Non-patterned fluorescent film 4,4°...Pair of deflection coils 5...
...gold filf film 6...
・Glass face plate 7・・・・・・Glass funnel

Claims (9)

[Claims] (1) At least one current modulating electron gun having a function of changing the current density of the electron beam emitted from it, and a non-pattern installed in the traveling direction of the electron beam so as to face the current modulating electron gun. a fluorescent film and a deflection device for creating a magnetic field perpendicular to the traveling direction of the electron beam to deflect the electron beam so that the entire surface of the non-patterned fluorescent film is excited by the electron beam and emits light; A phosphor comprising a coil, the non-patterned phosphor film exhibiting a sublinear current density-emission brightness relationship as the current density of the electron beam increases; When the current density of the beam increases, the current density becomes superlinear or more linear.
In a current-modulated multi-color cathode ray tube consisting of a phosphor that exhibits a luminance luminance relationship, the phosphor that exhibits the above-mentioned sublinear current density-emission luminance relationship has a compositional formula (%) (Ln is yttrium, gadolinium, etc.) , lanthanum, and lutetium, and X and y are respectively 10-4≦X≦9 X 10"2 and 10-6〈y<2
It consists of a europium and cerium activated rare earth oxysulfide yellow to red emitting phosphor represented by the following formula: A current-modulated multicolor cathode ray tube. (2) The current modulated multi-color cathode ray tube according to claim 1, wherein y is a number satisfying the condition: 2 x 1076≦y≦10-3. (3) The current modulated multi-color cathode ray tube according to claim 1 (4) or 2 (2), wherein said X is a number that satisfies the following conditions: 10'''2≦X≦8 (10-2). (4) -, 1: Valve distribution pattern The phosphor film has a layer composed of a phosphor exhibiting the above-mentioned sublinear current density-emission brightness relationship, and
The current modulation according to any one of claims 1 to 3, characterized in that the film has a two-layer structure composed of phosphors that exhibit a current density-emission brightness relationship. Type multicolor cathode ray tube. (5) A patent claim characterized in that the layer of the two-layer non-patterned phosphor film closer to the current modulated electron gun is composed of a phosphor exhibiting the sublinear current density-emission brightness relationship. The current modulated multicolor cathode ray tube according to item 4. (6) The above-mentioned non-patterned phosphor film is a mixture of the above-mentioned firefly/phosphor exhibiting a linear current density-emission brightness relationship and the above-mentioned phosphor exhibiting a super-linear or near-linear current density-emission brightness relationship. 4. A current modulated multicolor cathode ray tube according to any one of claims 1 to 3, characterized in that it is a single layer film made of a mixed phosphor. , (7) The phosphor particles exhibiting the sublinear current density-emission brightness relationship are attached to the surface of the phosphor particles in which the mixed phosphor exhibits the super-linear or linear current density-emission brightness relationship. 7. A current-modulated multicolor cathode ray tube according to claim 6, characterized in that it is a mixed phosphor. (8) Any one of claims 1 to 7, characterized in that the phosphor exhibiting the super-linear or linear current density-emission brightness relationship is a blue to green-emitting phosphor. The current modulating multicolor cathode ray tube described in the above section. (9) The phosphor exhibiting the above-mentioned super-linear or linear current density-emission luminance relationship is made of iron, cobalt, nickel and silver-activated zinc sulfide cadmium blue containing at least one metal of sodium. Either a green to green-emitting phosphor and a copper- and aluminum-activated zinc sulfide green-emitting phosphor containing at least one metal of iron, copper and nickel (* indicates both). 9. A current modulated multicolor cathode ray tube according to claim 8, characterized in that the current modulated multicolor cathode ray tube comprises: