JP2751413B2 - Phosphor screen for cathode ray tube - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a phosphor screen for a cathode ray tube used for a projector or a general color cathode ray tube. More specifically, the present invention relates to a blue phosphor layer having improved luminance saturation characteristics and luminance deterioration.

[Summary of the Invention]

The present invention provides, for example, a phosphor screen for a cathode ray tube used for a projector, a normal color cathode ray tube, or the like, in which the blue phosphor layer is activated by at least one of copper, gold and silver, and used as a co-activator. By comprising a phosphor layer comprising a mixture of a zinc sulfide phosphor containing a halogen element or aluminum and an yttrium silicate phosphor activated with at least one of cerium and gadolinium, the luminance of the blue phosphor layer is saturated. This is to improve characteristics and luminance degradation.

Further, the present invention provides the cathode ray tube phosphor screen, wherein the blue phosphor layer is a zinc sulfide phosphor activated by at least one of copper, gold and silver and containing a halogen element or aluminum as a coactivator. By laminating a yttrium silicate phosphor activated with at least one of cerium and gadolinium thereon, it is possible to improve luminance saturation characteristics and luminance deterioration of the blue phosphor layer in the same manner as described above. is there.

[Conventional technology]

A single-tube or three-tube projector has been proposed in which a large image is obtained by projecting a color image onto a screen through a lens system. Conventionally, in a phosphor screen for a cathode ray tube used in such a projector, that is, a phosphor screen formed by applying a phosphor layer on the inner surface of a face plate of the cathode ray tube, ZnS: Ag, Al phosphor is particularly used as the blue phosphor. Has been used.

JP-A-54-100663 discloses a phosphor screen for a cathode ray tube used in a radar or the like, in which a cerium-activated yttrium silicate phosphor is provided on a first-layer phosphor made of copper-activated zinc cadmium sulfide phosphor. A phosphor screen for a cathode ray tube has been proposed in which a second-layer phosphor made of is formed, the second-layer phosphor is excited to emit light, and the emitted light causes the first-layer phosphor to emit light.

[Problems to be solved by the invention]

However, ZnS: Ag, Al used as the above-described blue phosphor for a projector has poor luminance saturation characteristics when highly excited by electron beam irradiation. For this reason, the set of projectors must be used in a state where the electron beam is not completely focused on purpose, and as a result, there has been a problem that the resolution of blue color does not increase. Also,
ZnS: Ag, Al is liable to cause luminance degradation due to electron beam irradiation,
It cannot be highly excited. Therefore, there is a disadvantage that the brightness of the whole (when white) is restricted in the projector.

The present invention has been made in view of the above circumstances, and provides a phosphor screen for a cathode ray tube, which can improve luminance saturation characteristics and luminance degradation of a blue phosphor.

[Means for solving the problem]

The phosphor screen for a cathode ray tube according to the present invention is a zinc sulfide phosphor in which at least one of copper, gold and silver is activated on the inner surface of a face plate (1) of the cathode ray tube and contains a halogen element or aluminum as a co-activator. (2) and a phosphor layer (4) (or (6)) formed by mixing an yttrium silicate phosphor (3) (or (5)) activated with at least one of cerium and gadolinium. It is composed.

Another phosphor screen for a cathode ray tube according to the present invention is zinc sulfide in which at least one of copper, gold and silver is activated on the inner surface of the face plate (1) of the cathode ray tube and contains a halogen element or an animinium as a co-activator. A phosphor (2);
A yttrium silicate phosphor (7) activated by at least one of cerium and gadolinium is laminated thereon.

[Action]

According to the configuration of the first invention described above, the blue phosphor is formed by the phosphor layer formed by mixing the zinc sulfide-based phosphor (2) and the yttrium silicate-based phosphor (3) (or (5)). By forming the body layer (4) (or (6)), the zinc sulfide-based phosphor (2) is irradiated with an electron beam.
Is a direct and the above yttrium silicate based phosphor (3)
In addition to the excitation light emission by the electron beam irradiated through (or (5)), the light emission is excited by the light emission generated by the electron beam excitation of the yttrium silicate-based phosphor (3) (or (5)). The yttrium silicate-based phosphor (3) (or (5)) emits light in the vicinity of the excitation band of the zinc sulfide-based phosphor (2) when excited and emits by irradiation with an electron beam, and furthermore, its luminance is deteriorated. It is a difficult phosphor. The luminance saturation characteristics of the blue phosphor layer (4) are improved by the excess action of the electron beam excitation and the photoexcitation, and the luminance degradation is caused by the presence of the yttrium silicate-based phosphor (3) (or (5)). Be improved.

According to the second aspect of the present invention, the blue phosphor layer (8) is formed by laminating the yttrium silicate-based phosphor (7) on the zinc sulfide-based phosphor (2). As a result, when the electron beam irradiation is performed, the phase of the zinc sulfide-based phosphor (2) is excited by an electron beam and the phase of light excitation by the light emission from the yttrium silicate-based phosphor (7), as described above. It emits light by surplus action, and the blue phosphor layer (8)
, The luminance saturation characteristic and the luminance deterioration of the pixel are improved.

〔Example〕

Hereinafter, an embodiment of a phosphor screen for a cathode ray tube according to the present invention will be described with reference to the drawings.

FIG. 1 shows a first embodiment of the present invention, in which ZnS: is formed on the inner surface of a face plate (1) made of glass of a cathode ray tube.
A blue phosphor layer (4) is formed by mixing an Ag, Al phosphor (2) and a Y ₂ SiO ₅ : Ce, Gd phosphor (3).

In this configuration, when the blue phosphor layer (4) is irradiated with an electron beam from an electron gun (not shown), the ZnS: Ag, Al phosphor (2) is excited by the electron beam to emit light, and Y ₂ SiO _{5 is} emitted. : Ce,
The Gd phosphor (3) emits light near the excitation band of ZnS: Ag, Al due to the electron beam, and this light emission also causes the ZnS: Ag, Al phosphor (2).
Emits excited light.

The Y ₂ SiO ₅ : Ce, Gd phosphor (3) is a phosphor that hardly causes luminance saturation due to high excitation and is hardly deteriorated in luminance. Therefore,
According to the above configuration, the ZnS: Ag, Al phosphor (2) emits light by the additive action of electron beam excitation and photoexcitation, thereby improving the luminance saturation characteristics of the blue phosphor layer (4). It is possible to improve the luminance deterioration. FIG. 2 shows the luminance saturation characteristics (curve a ₁ ) of the blue phosphor layer (4).
This is shown in comparison with the luminance saturation characteristic (curve b) of the blue phosphor layer containing only ZnS: Ag, Al. Note that the curve a ₁ has ZnS: Ag, Al of 90%, Y
_This is the case where the mixing ratio of ₂ SiO ₅ : Ce, Gd is 10%. As apparent from FIG. 2, the blue phosphor layer (4) of the present invention is
The luminance saturation characteristics in the range covering the practical range (10 μA / cm ^{2 to} 80 μA / cm ² ) are improved as compared with the case of using only ZnS: Ag, Al.

FIG. 3 shows a second embodiment of the present invention, wherein ZnS: Ag, Al phosphor (2) and Y ₂ SiO ₅ : Ce phosphor (5) are provided on the inner surface of a face plate (1) of a cathode ray tube. Are formed to form a blue phosphor layer (6). FIG. 4 shows the luminance saturation characteristic (curve a ₂ ) of the blue phosphor layer (6) as ZnS:
The results are shown in comparison with the luminance saturation characteristics (curve b) of the blue phosphor layer containing only Ag and Al. Note that the curve a ₂ has ZnS: Ag, Al of 90%, Y ₂ SiO ₅ : C
This is the case where e is 10%.

FIG. 5 shows the luminance saturation characteristics of only the ZnS: Ag, Al phosphor (curve b), the luminance saturation characteristics of only the Y ₂ SiO ₅ : Ce, Gd phosphor (curve c), and the Y ₂ SiO ₅ : Ce fluorescence. The luminance saturation characteristic of only the body (curve d) is shown.

In the blue phosphor layer (6) shown in FIG. 3, ZnS:
Ag, Al phosphor (2) emits light due to the combined effect of electron beam excitation and photoexcitation due to light emission from Y ₂ SiO ₅ : Ce phosphor (5),
As is clear from FIG. 4, the range covering the practical range (20 μA / cm ^{2 to} 80 μA / c) as compared with the case of only ZnS: Ag, Al
The luminance saturation characteristic at m ² ) is improved. Also, Y ₂ SiO ₅ : C
Since the e-phosphor (5) is also a phosphor that hardly deteriorates in luminance, the change in luminance is also improved in the blue phosphor layer (6).

On the other hand, as is clear from FIGS. 2 and 4, ZnS: A
g, Al phosphor (2) mixed with Y ₂ SiO ₅ : Ce phosphor (5), rather than Y ₂ SiO ₅ : Ce, Gd phosphor (3)
It can be seen that the blue phosphor layer (4) in which is mixed improves the luminance saturation characteristics.

FIG. 6 shows a third embodiment of the present invention, in which a ZnS: Ag, Al phosphor (2) is applied to the inner surface of a face plate (1) of a cathode ray tube, and is laminated thereon. Y ₂ SiO ₅ : G
d The phosphor (7) is applied to form a blue phosphor layer (8). Also in this configuration, an electron gun (not shown)
Irradiates the blue phosphor (8) with an electron beam from ZnS: A
The g, Al phosphor (2) emits light when excited by electron beam irradiation, and the Y ₂ SiO ₅ : Gd phosphor (7) emits light near the excitation band of ZnS: Ag, Al due to the electron beam. : Ag, Al phosphor (2) emits light by excitation. Y ₂ SiO ₅ : Gd phosphor (7)
It is a phosphor that hardly causes luminance saturation due to high excitation and hardly deteriorates in luminance. Therefore, also in this blue phosphor layer (8), ZnS: Ag, Al is similar to the case of FIGS. 1 and 3 described above.
The phosphor (2) emits light due to the surplus action of the electron beam excitation and the light excitation, so that the luminance saturation characteristics can be improved and the luminance deterioration can be improved.

In the mixed type shown in FIGS. 1 and 3, ZnS: Ag, Al phosphor (2) is replaced by Y ₂ SiO ₅ : Ce, Gd phosphor (3) or Y ₂ SiO ₅ : Ce.
Phosphor (5) was mixed, but ZnS: Ag, Al phosphor (2)
_May be mixed with a Y ₂ SiO ₅ : Gd phosphor (7).

In the laminated type shown in FIG. 6, ZnS: Ag, Al phosphor (2)
The Y ₂ SiO ₅ : Gd phosphor (7) was applied on the top, but the Y ₂ SiO ₅ : Ce, Gd phosphor (3) or Y ₂ SiO ₅ : C was applied on the ZnS: Ag, Al phosphor (2).
e The phosphor (5) may be applied.

And in these laminated type and mixed type,
Practically, the concentration of Ce and Gd, which are activators of Y ₂ SiO ₅ , is C
Concentration X ₁ of e is 0.1 mol% ≦ X ₁ ≦ 1 mol%, the concentration X ₂ of Gd 0.5
Mol% ≦ X ₂ ≦ 5 mol%. Also, Y ₂
The amount of the SiO ₅ -based phosphors (3), (5) and (7) may be 40% or less of the whole. If over 40%, ZnS: A
Does not overtake the luminance saturation characteristics of g and Al.

As described above, ZnS: Ag, Al phosphor (2) and Y ₂ SiO ₅
By forming a blue phosphor layer (4), (6) or (8) by mixing or laminating with a phosphor (3), (5) or (7) based on the conventional ZnS: The luminance saturation characteristic and the luminance deterioration can be improved as compared with the blue phosphor layer including only the Ag and Al phosphor (2). Therefore, for example, when used in a projector or the like, the electron beam can be used in a perfect focus state, the resolution of blue can be improved, and the overall brightness (when white is set by red, green, and blue). And the life of the cathode ray tube can be extended.

In the above example, the present invention is applied to a blue phosphor layer for a projector. However, the present invention can also be applied to a blue phosphor layer of an ordinary color cathode ray tube or the like.

〔The invention's effect〕

According to the phosphor screen for a cathode ray tube of the present invention, a zinc sulfide phosphor which is activated by at least one of copper, gold and silver and contains a halogen element or aluminum as a co-activator, and cerium and gadolinium on the inner surface of the face plate. By forming a blue phosphor layer by laminating or mixing yttrium silicate phosphor activated by at least one of them, luminance saturation characteristics and luminance deterioration of the blue phosphor layer can be improved. Therefore, it is possible to irradiate the electron beam in a perfect focus state, to increase the resolution of blue, and to improve the overall (white) brightness of a color image. In addition, the life of the blue phosphor layer can be extended, and the life of the cathode ray tube can be extended.

[Brief description of the drawings]

FIG. 1 is a sectional view showing an embodiment of a phosphor screen for a cathode ray tube according to the present invention, FIG.
FIG. 4 is a cross-sectional view showing another embodiment of the phosphor screen for a cathode ray tube according to the present invention. FIG.
FIG. 6 is a diagram showing a luminance saturation characteristic for explaining the present invention, and FIG. 6 is a sectional view showing still another embodiment of the phosphor screen for a cathode ray tube according to the present invention. (1) is a face plate, (2) is a ZnS: Ag, Al phosphor, (3) is Y ₂ SiO ₅ : Ce, Gd phosphor, and (5) is Y ₂ SiO ₅ : Ce.
The phosphor, (7) is a Y ₂ SiO ₅ : Gd phosphor.

Claims (2)

(57) [Claims] 1. A zinc sulfide phosphor activated by at least one of copper, gold and silver and containing a halogen element or aluminum as a coactivator, and at least one of cerium and gadolinium on an inner surface of a face plate of a cathode ray tube. A phosphor screen for a cathode ray tube, comprising a phosphor layer formed by mixing the yttrium silicate phosphor activated in the above. 2. A zinc sulfide phosphor activated by at least one of copper, gold and silver and containing a halogen element or animinium as a co-activator, and a cerium and gadolinium on the inner surface of the face plate of the cathode ray tube. A phosphor screen for a cathode ray tube, wherein at least one kind of activated yttrium silicate phosphor is laminated.