JPS58154785A - Blue light emitting fluorescent material - Google Patents

Abstract

PURPOSE:To form at a low cost a blue light emitting fluorescent material for low-speed electron beam excitation excellent in luminance, by mixing a fluorescent material obtd. by doping ZnS with a given proportion of Ag and Al, with a metal oxide. CONSTITUTION:High-purity ZnS is immersed in an aq. soln. of given concn. of Al2(SO4)3.18H2O and of AgNO3 and, after dried at about 100 deg.C, the obtd. powder is thermally treated in a H2S atmosphere at about 600-800 deg.C for about 2-24hr to form a blue light emitting fluorescent material having Ag concn. of 0.05-1.12m/o based on Zn and an Al/Ag concn. ratio of 1:2-1:3. Then the fluorescent material is mixed with a metal oxide such as an electrically conductive InO3 powder.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a phosphor K for excitation with slow electron beams that emits blue light.
There is something to do.

In the field of display devices, in preparation for the era of flat panel displays, we are developing liquid crystals (LCDs), light emitting diodes (IJDs), plasma displays (PDPs),
Research is being carried out on various flat screen display devices such as EL panels, flat CRTs, and fluorescent display tubes. Flat CRT with electron 1lIllI originating from IP#.

Fluorescent display tubes are characterized by high brightness and are expected to be put into practical use.

Among the phosphors for low-speed electron beam excitation used in these devices, the brightness of the blue Komama phosphor is lower than that of the color of the blue color, resulting in colorization. High brightness G is absolutely necessary for fluorescent display tubes for automobiles.
O Blue-emitting phosphor all of us are affected.

Currently, Zs8:At phosphor is used as a blue phosphor. ZII8: At #i high encounter electronic embroidery-
It is known as a blue phosphor with high brightness, and is used in color televisions, etc., but it does not emit 11iI"t" rays when driven by low-speed electrons at several tens of volts like fluorescent display tubes, and it does not emit 11iI"t" rays like fluorescent display tubes. In the case of m11 with a highly exposed electron coil of several tens of KV, the charging is relaxed by secondary electrons, and at the same time, the electrons penetrate into the interior of the phosphor particles against the charging and accumulate, whereas the low voltage To 9, 2 just by hitting the phosphor 0 shallowly with electron-bound excitation.
118: When it is an insulator like At, O becomes $1 when excited by charging.

In order to remove this charge, KI% 10m conductive powder is mixed. When the mixed phosphor of 2% 8:At and Im01 was exposed, the surface of the Zs3:Ay phosphor came into contact with the conductive powder and the potential for electrons decreased (1111K, 9 times the charge). (removed)), electrons are incident near the contact point, and ZI8:AI
emits light. In such a tS phosphor, directly l5lO
@ K Incident electrons do not contribute to light emission KiJ, much less Δ
The phosphor using a slow electron beam NIJ with a quantity lattice of tSt- is one that emits tSt-. In order to solve lI during this period, it is sufficient to make the phosphor low in resistance.In the case of a phosphor containing Cd (ZsCd) whose parent lattice is S, doping with AJv increases the resistance of the phosphor.
Therefore it is resolved. However, in the case of 2%S, A
When Iv dog, Zs vacancy is generated and the charge is compensated,
The carrier strength does not increase and the resistance does not become low. zs9
As a method of doping KAJ without creating a lattice, Zs8
In the case of a single crystal, a method of heat treatment in 2% steam in a vacuum is used, but this method is impractical in the case of a monolithic phosphor used in AMECS.

Based on the above-mentioned circumstances, the inventors of the present invention investigated a method of reducing the resistance of zI&s:~M using a normal production method.
tL ”C'vh 6Ap# (L O11mla h
In addition, a large amount of M
They discovered that the brightness of the ZJ:AtAj f& superimposed light body could be improved by suppressing the generation of mu vacancies by lowering the doping Ilf.

2 Duck 8: AI's true threat party is a party created by the recombination of Donor and Aku Ambuta. To5 with A#a aterceptor,
Donor ion is introduced from 5ml I4] - Logon ion is intentionally introduced Aj% Is, Gg, etc.

The amount of these impurity ions is 9II: @1: Oka; Naoso's Apa O1m m1m, and AJt et al. (103%/#).
It is. This is often explained in the coordination manual.
48, the number of wave mobilizations in the excited state is large, and the formation of a donor-acceptor pair spans several tens of AK4s, so the interaction between a trap and a donor-acceptor pair is 1 dl.
If the fiber boundary around Ml is at these values, it will be very sharp.

However, already Kj1! As mentioned above, in the case of mixed fluorophores, the ZsS:AtAJo maximum condition does not necessarily apply, because #I & The brightness as a light body is 0. According to Motoya @, by increasing the difference between the TIdAJ doping and the AJ doping amount, an increase in carrier 11) is promoted, and charge compensation is suppressed by doping at a relatively low temperature station.

The brightness Kv of the mixed phosphor can be improved.

The present invention will be explained below based on Examples.

Examples> 919? ? ? Ml (
S04)s・1s)I was impregnated with an aqueous solution of i,0 and AINO. This and lAtoa degree for 2 ducks α01
鵠／・〜α15e'e 't changed it. Also, the degree of M was varied from 1 to 5 times compared to ~. 10 of the impregnated powder
Hui H dried at 0℃, 600℃~80 in 8 atmosphere 5
Heat treatment was performed at 0° C. for 2 to 24 hours.

The obtained Zl@S:A#AJ fluorophore and 1 town 0. The conductive powder was combined in a weight ratio of 725. Jin's l510-electric powder is r
,o.

The raw material powder was dissolved in HCjK#1, and NH and OH were added to form an indium hydroxide precipitate. This was washed with water, filtered, dried, and then thermally decomposed in air to obtain a product.

The mixed phosphor was coated with water on the substrate on which the phosphor was vapor-deposited, and after heat treatment at 400°C for 10 minutes in air and 10 minutes in nitrogen, an oil-free product as shown in 1I11!1g1K was applied. Evaluation was carried out using a demantaple low-uniform electron-entrained excited cathode luminescence evaluation device.

That is, a substrate 7 on which a phosphor S is installed is housed in a vacuum chamber 1, and electrons S% emitted from a cathode 2: a phosphor 50
The relationship between the doping amount of ApAj and the brightness is determined by irradiating the IJa light image with 111 rays. Note that 4 in the figure is a grid and 6itllll[i.

The vacuum f at a constant time was I x 10''''Tore, and the anode voltage was 50 ■ AI for the case of heat treatment at 700°C for 10 hours.

The relationship between the concentration of M and the brightness is shown in Figure 2. The ratio of At and AJ was kept constant at 1:2. It has been shown that the brightness of the vortex phosphor is improved by adding 4AJ in the region where 'aIIl quenching occurs.

As mentioned above, single ray #4 is considered to be suitable for use as a powder phosphor due to increased cost, and instead of Zs, which is low cost and has improved brightness. %s
: It has the effect that hphi phosphor vII can provide.

[Brief explanation of the drawing]

Figure 1 is a horizontal lFrl1lIWJ diagram of the evaluation II device for demantaple low electron-encoupled excitation cuddle ζ-ness, and Fig. 2
FIG. 11 is a diagram showing the relationship between 11Fi%O-degree and brightness. Patent applicant: NEC Co., Ltd. 1 AC

Claims (1)

[Claims] (1) 2% 8: A combination of AtAI and a metal oxide gives At0IIlf for the film (LOS ~a
1211/6. AJf to At) vortex layer 1:2 ~
A blue-emitting phosphor for slow electron beam excitation, characterized in that the ratio is 1:1.