JP2723717B2 - Fluorescent display tube - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fluorescent display tube, and more particularly, to a flat emission type fluorescent display tube using a (Zn, Cd) S: Ag, Cl phosphor.

[0002]

2. Description of the Related Art A flat light emitting fluorescent display tube for observing light emitted from a phosphor on an anode substrate as a display pattern through a light-transmitting insulating substrate generally has a structure shown in FIG. That is, the power supply wiring 2 made of an Al sputtered film is formed on the glass base plate 1 and the insulating layer 3, (Zn, Cd) S: A
g and Cl-based phosphor layers 7 are sequentially applied and formed to form an anode substrate, on which grids 4 and filaments 5 are arranged, sealed with a cover glass 6 and vacuum sealed to form a fluorescent display tube. When the (Zn, Cd) S: Ag, Cl-based phosphor layer 7 is used for the phosphor layer, a phosphor which has not been coated with a particle surface using an oxide of Si, Al, Zn or the like is conventionally used. Was.

[0003] In order to emit light at a low operating voltage of a fluorescent display tube of about 10 to 40 V, this kind of phosphor requires In ₂
A conductive powder such as O ₃ is used.

[0004]

Conventionally, when a (Zn, Cd) S: Ag, Cl-based phosphor is used in a flat emission type fluorescent display tube, the phosphor without a particle surface coating has been used. Therefore, there is a problem in that the phosphor is quickly deteriorated by ion sputtering or the like due to a residual gas during the lighting operation and the life is shortened.

Further, when a phosphor coated with particle surfaces of oxides of Si, Al, Zn or the like is used, the surface coating impairs the conductivity of the phosphor particles themselves, resulting in low brightness and However, there is a problem that uneven light emission occurs.

Attempts have been made to increase or decrease the amount of surface coating, but no effect has been obtained on the above-mentioned problems.

An object of the present invention is to provide a fluorescent display tube having a long life, high luminance, and uniform light emission.

[0008]

According to the present invention, at least a thin-film metal electrode and (Zn, Cd) S: A
a flat emission type fluorescent display tube having an anode on which a phosphor layer made of g, Cl-based phosphor is formed, and observing light emitted from the phosphor layer as a display pattern through the translucent insulating substrate. Wherein (Zn, Cd) S: Ag, C
A phosphor layer made of an l-type phosphor is used to coat phosphor particle surfaces with Si,
It is composed of a mixture of a phosphor coated with at least one of the oxides of Al and Zn and a phosphor not coated.

Further, the phosphor layer comprising the above-mentioned mixture has a phosphor particle surface coated with at least one oxide selected from oxides of Si, Al and Zn by 10 to 60 wt.
%contains.

[0010]

Next, an embodiment of the present invention will be described with reference to the drawings.

FIG. 1 is a partially cutaway side view illustrating an embodiment of the present invention.

As shown in FIG. 1, first, A
(1) After forming a power supply wiring 2 composed of a sputtered film by photolithography and forming an insulating layer 3, furthermore, (Zn, Cd)
S: Ag, Cl-based phosphor layer 8 was applied by a screen printing method. The phosphor layer 8, a phosphor not subjected to particle surface coating, made from a mixture of phosphor subjected to particle surfaces coated by SiO _2, about the particle surface coated by SiO ₂ in the mixture phosphor 300 [mu] g / g applied phosphor at 0 wt%, 20 wt%, 40 wt%, 80 wt%, 10 wt%
A phosphor mixed at a ratio of 0 wt% was prepared and used. A grid 4 and a filament 5 are placed on the anode substrate thus obtained.
And vacuum sealing after sealing with the cover glass 6 to produce a fluorescent display tube.

FIG. 2 is a characteristic diagram showing the relationship between the mixing ratio of the phosphor coated with the particle surface in the mixed phosphor and the relative luminance.
FIG. 3 is a characteristic diagram showing the relationship between the operation time and the luminance reduction rate.

Next, when the luminance when only the phosphor not coated with the particle surface, which is a standard of the thus obtained fluorescent display tube, is used as 100% and the relative luminance is 100%, the relative luminance is expressed in relation to the mixing ratio. As shown in FIG.
It was found that the luminance decreased as the mixing ratio of the phosphor coated with the particle surface with O ₂ increased from 60 wt%.

In the forced life such as life evaluation in an atmosphere of 80 ° C., the luminance decrease rate after 1,000 hours of operation with respect to the initial luminance is not as shown in FIG. It is improved by 5% to 15% with respect to 100% by weight of the phosphor.

[0016] Furthermore, the life was improved even with the mixed phosphor having a mixing ratio of 10 wt% of the phosphor coated with the particle surface with SiO ₂ .

Incidentally, oxides of Al and Zn (Al ₂ O ₃ , Z
The same results as described above were obtained even when a phosphor coated with a particle surface with nO or the like was mixed.

[0018]

As described above, the present invention relates to a flat emission type fluorescent display tube in which a phosphor layer made of (Zn, Cd) S: Ag, Cl-based phosphor is not coated with a particle surface. The use of a phosphor composed of a mixture of phosphors coated with at least one oxide of oxides of Si, Al and Zn on the surface of the particles has the effect of improving the lifetime without impairing the initial luminance.

Further, for the mixed phosphor, Si, Al,
The above effect can be remarkably obtained by mixing a phosphor coated with a particle surface with at least one oxide of Zn in a range of 10 to 60 wt%.

[Brief description of the drawings]

FIG. 1 is a partially cutaway side view illustrating an embodiment of the present invention.

FIG. 2 is a characteristic diagram showing a relationship between a mixing ratio of a phosphor coated with a particle surface in a mixed phosphor and relative luminance.

FIG. 3 is a characteristic diagram illustrating a relationship between an operation time and a luminance reduction rate.

FIG. 4 is a partially cutaway side view of an example of a conventional flat emission type fluorescent display tube.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Glass base plate 2 Power supply wiring 3 Insulating layer 4 Grid 5 Filament 6 Cover glass 7,8 (Zn, Cd) S: Ag, Cl-type phosphor layer

Claims (2)

(57) [Claims] 1. A light-transmitting insulating substrate having at least a thin-film metal electrode and an anode on which a phosphor layer made of a (Zn, Cd) S: Ag, Cl-based phosphor is formed. In a flat emission type fluorescent display tube for observing the light emission as a display pattern through the translucent insulating substrate, the phosphor layer made of the (Zn, Cd) S: Ag, Cl-based phosphor has a phosphor particle surface. A fluorescent display tube comprising a mixture of a phosphor coated with at least one oxide of Si, Al, and Zn and an uncoated phosphor. 2. The phosphor layer comprising the mixture contains 10 to 60% by weight of a phosphor having a phosphor particle surface coated with at least one oxide of Si, Al and Zn. The fluorescent display tube according to claim 1.