JPS63101476A - Color display tube - Google Patents

Abstract

PURPOSE:To provide a color display tube which has high fineness, hardly causes flickering and is clear, by separately applying each of a red light-emitting phosphor, a green light-emitting phosphor and a specified blue light-emitting phosphor in independent patterns. CONSTITUTION:Each of a red light-emitting phosphor [e.g., Zn3(PO4)2: Mn<2+>], a green light-emitting phosphor (e.g., Zn2SiO4: Mn<2+>,As) and a blue light-emitting phosphor contg. at least 50wt% phosphor of formula (Sr1-uCau)1-vMnvSb2O4 (wherein 0<=u<=0.15;0.03<=v<=0.3) is separately applied in independent patterns.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention is applicable to display tubes for computer terminals, especially for applications that require high definition such as color graphics and kanji display, and has a relatively low screen repetition frequency. Regarding color display tubes.

[Conventional technology]

In recent years, there has been an increasing demand for high-definition color display tubes for computer terminals. However, if an ordinary short afterglow type phosphor is used and the image is reproduced at a commercial frequency and only the number of scanning lines is increased, the screen will flicker significantly, increasing the fatigue of the terminal user. Therefore, two methods have been adopted: one uses a long afterglow phosphor without increasing the reproduction frequency of the screen, and the other uses a short afterglow phosphor to increase the reproduction frequency. If the latter method is adopted, the electron beam deflection power supply and deflection coil must be of high frequency type, which poses technical problems and significantly increases the cost. Therefore, the former method is considered to be more preferable, but at present, because the brightness of long afterglow phosphors is insufficient, they are often used in combination with high brightness short afterglow phosphors.

Among the three primary colors, green contains ZnzSs04 :Mn +
As (P39) + Zn3 (PQG)2 for red
: Mn (P27) has been put into practical use as a long afterglow phosphor. On the other hand, blue phosphors have particular problems.
There is still no definitive product for practical use. We will describe the characteristics of the two types of materials that have been announced so far.

(i) ZnS:Ag+M+XsHowever, M-In
or Ga, X-halogen or AI.

This phosphor has been put to practical use to some extent. However, it shows remarkable brightness saturation, lacks brightness at high electron beam current density (line 14 in Figure 1), and has a "tailing type" afterglow characteristic with a long afterglow component with a low brightness level. ” (lines 22 and 23 in Fig. 2), and that the afterglow characteristics and emission color change depending on the current density (Fig. 2 and Reference 3).

(ii) CaF2:Mn +R; However, R-Yb”
or S--This phosphor has a long exponential afterglow, but the emission color is close to green, and therefore it has been proposed to be used in combination with a short afterglow blue phosphor. Furthermore, there are drawbacks such as burnout and brightness saturation.

Due to the above circumstances, even when using long afterglow phosphors for red and green, it is unavoidable to use short afterglow phosphors ZnS for blue.
: Ag, CI (P22B) is often used,
In this case, in an image or pattern whose color tone is close to blue, short blue afterglow becomes dominant, and flickering becomes thicker, which is undesirable for use.

On the other hand, the target here is 5rSb206: Mn, Ca5
b206: For l'In, M.L.N.A.;
Page 34B (M, L, Yu.

A11salu; Izvest, ^kad, Nauk,
5SSR23 (1959N346-1348) and Joseph Janin, Roger Bernard; Contou Landue 237 (1953) pp. 798-800 (J, Ja
nin et R, Bernard; Compt, re
nd, 237 (1953) 798-800), but all of them only refer to the crystal structure or emission spectrum, and do not mention afterglow characteristics, how to use them, or luminous efficiency by electron beam excitation. Not yet.

[Problem that the invention seeks to solve]

An object of the present invention is to provide a color display tube that is easier to see and has less flickering by using a blue phosphor having good luminous efficiency and afterglow properties.

[Means for solving problems]

The present inventors have discovered that the luminescence of a substance with the following compositional formula exhibits a long exponential decay, and also flickers (
It was confirmed that there was little frifuka).

(sr/-, Cau door, Mu, 5b2o6 but O≦U≦
1 0.02≦V≦0.3 In particular, the U=O composition exhibits light emission with almost constant chromaticity coordinates x-0,10, y-0,125 within the range of V above, regardless of the value of V. , this color is a sufficiently highly saturated blue.

Furthermore, it has become clear that the luminance saturation phenomenon is relatively small regardless of the value of U. Line 13 in FIG. 1 shows the relationship between brightness and electron beam current for the composition U=0.
The relationships for the composition i) ZnS:Ag,Ga,CI (line 14 in Figure 1) and the short afterglow phosphor ZnS:Ag,CI (line 11 in Figure 1) are also listed for comparison. be. This figure was measured by applying only blue color to the entire surface of a 14-inch color display tube panel for experimental purposes.The horizontal axis is the ° value obtained by dividing the electron beam current by the Lasceux area.The operating conditions of the color display tube are When producing a character pattern, the current is usually 1~2X1
02 μA, the value on the horizontal axis in Figure 1 is 0.2 to 0.3.
It is around μ^/cd.

The dependence of brightness on current density is not linear and there is a tendency for brightness saturation, but 5rSb206:Mn'' or a mixed crystal of this and Ca5bz06:Mn'' is similar to the conventional long afterglow phosphor ZnS:Ag. , Ga, and CI.For this reason, 5rSb2%:Mn is characterized by higher brightness than conventional products in the above current density region. Ca5b201. :Mn, the color tone shifts towards green (point 32 in Figure 3).
33, 34, 35), the brightness naturally increases (line 12 in FIG. 1).

The afterglow characteristics after electron beam pulse irradiation are shown in FIG. 2. Ideally, the light emission should continue until the screen changes, and disappear at the next screen. When the reproduction (frame) frequency is 50 Hz, such an ideal characteristic is shown by line 25 in FIG. Of course, such a damping characteristic is impossible, and the exponential type is actually the most preferable one. The case is shown by line 21 in FIG. Similarly, lines 22 and 23 in FIG. 2 are the characteristics of ZnS:Ag, Ga, and CI. This type deviates from the exponential function type, leaving weak luminescence. A phenomenon in which the attenuation becomes faster as the current increases is also observed.

Usually, the time for the intensity to drop to the initial value of 1710 (10χ afterglow time) is used as an index, but this does not reflect the shape of the attenuation curve as described above. Therefore, when these two types of materials are compared, it is expected that the difference in flickering effect will be smaller than expected from the 10x afterglow time.

FIG. 4 shows the relationship between relative brightness and Mnn density color when u=0. The optimum value of Mn4 degrees is around V-0,1,
The brightness has a wide peak. The value of ■ was limited because it was determined that a range of 70% or more of the peak value was practically meaningful.

[Effect]

Due to the above characteristics, this material has a blue component,
A color display tube made entirely of long afterglow phosphors combined with red and long line afterglow phosphors can be manufactured to improve the brightness of the phosphor surface. As the value of U increases, the brightness increases significantly, but at the same time the color tone approaches green and the color reproduction range of the screen narrows.In the ex+Y coordinate system, the area of the triangle determined by the three chromaticity points and the relative brightness of blue color When the product is used as a measure, the maximum value appears at approximately U·0.15. Therefore, we thought that there would be an advantage in narrowing the color reproduction range to this value, so we limited U.

〔Example〕

The present invention will be further explained below with reference to Examples.

Example 1 P39 (Zn2Si04:Mn, A
s), as the red component P27(Zn7(PO4)z:
Mn), S rO,qMn,,5b as a blue component
20. A 14-inch collar tube was prototyped using this. Also, as a blue component, P 22 B * Z n S : A g
A tube using + Ga + CI was also manufactured for comparison.

First, a character pattern consisting of a series of H characters is displayed in white, and the frame frequency of the screen is gradually decreased from 60Hz to the frequency at which flickering begins (critical fusion frequency, 0FF).
I asked for The brightness of the screen at this time is approximately 5 ft-L,
The subject observed with both eyes at a position 50 cm from the screen. The CFF is 45-47Hz for the tube using the above developed product.
The frequency was 60 Hz for the tube using P22B, and a reduction in flicker was observed by using the developed product. For comparison, Z n S: A g
When a similar test was conducted on a tube using + Ga + CI, a CFF of 53 to 56 Hz was measured, which also showed that Sr, 7. There was a large difference from the case of using yMn, 7Sb206.

Next, we produced a warm white color with a chromaticity point of x = 0.35 + y = 0.39 in the form of a single scanning line, sent it from the top of the screen to the bottom, and observed the afterglow with the naked eye. The tube used in the work remained white, but a slightly reddish afterglow was observed in the tube used in P22B. The long afterglow of all three primary colors improves the afterglow characteristics of the mixed color.

Next, a pattern consisting of a series of H letters was displayed only in blue, and the time-averaged luminance of the three types of tubes was examined with a frame frequency of 50 Hz.

5rSb, 0. : The brightness of the prototype sphere using Mn is ZnS:Ag.

The brightness was 15χ higher than that of the Ga and CI bulbs. The current density at this time seems to be around 0.15 μA/cd as shown in FIG.

Example 2 P39 as a green component. P27 as a red component. As a blue component, C3ro, yjCa, tg>ty, qg M
A 14-inch LCD display tube was prototyped using nty and aisSbz06. Regarding the frizz and afterglow characteristics, almost the same results as in Example 1 were obtained. The brightness of the blue H-shaped pattern is Z
nS: 60χ higher than the luminance using the A g + Ga + CI method.

Example 3 A mixture of P39 and P31 (ZnS:Cu) (weight ratio 92:8) as a green component, P27 and P22 as a red component
Mixture of R(Y20x S :Eu) (weight ratio 85:1
5''), Sr as the blue component, 7 M', 3
A 14-inch power display tube was prototyped using a mixture of Sbz 06 and P22B (MNN131). The CFF of the blue component measured in the same manner as in Example 1 was 48 to 50 Hz, and P22
A result improved by about 10 Hz compared to the case where only B is the blue component was obtained.

The afterglow characteristic of the blue component is as shown by line 24 in Figure 2, and P
The fast afterglow component of 22B appears largely at the beginning and is no longer of an exponential type. However, the color tone is close to P22B and the third
The blue brightness was improved as shown by point 39 in the figure, and the blue brightness was improved by ZnS:Ag.
, Ga, and CI alone were used. ball,
High brightness short afterglow phosphor even in red (P31, P22R)
In conjunction with the addition of , we were able to significantly improve overall brightness and reduce flicker to some extent.

〔Effect of the invention〕

As explained above, according to the present invention, it is possible to manufacture a color display tube with high blue brightness while maintaining a flicker reduction effect comparable to that of conventional phosphors. This results in 0.2
It is possible to improve the brightness of high-definition tubes with a pitch of ~0.3 or ultra-high-definition tubes with a pitch smaller than that, and provide a screen that is easier to see than before.

[Brief explanation of the drawing]

Figure 1 is a diagram showing the dependence of the brightness of various blue phosphors applied on a cathode ray tube on current density (beam current/raster area).
Figure 2 is an afterglow characteristic diagram of various blue phosphors, Figure 3 is an emission chromaticity point diagram of various phosphors, and Figure 4 is 5r1-yF1nysb.
206 is a diagram showing the dependence of brightness on Mn concentration (v) in No. 206. FIG. Explanation of symbols Fig. 1 It-=ZnS:Ag, C1 12---(Sr,, 2pa, 7, 7.y) Sb, 0,
5: Mn13--SrSb206: Mn14--ZnS:Ag, Ga, CI Fig. 2 2l-=SrSb2%iMn (0.25-1.0μΔ/
cfa current density)22-=ZnS:Ag, Ga, C
I (0,254A/cn)23---ZnS: 8g, G
a, CI (1, OμA/cd) 24--ZnS: 8g,
CI +5rSb206:Mn(1:1)25-・
Ideal afterglow characteristics at frame frequency 50Hz Fig. 3 3t-=SrSb206: Mn2t32---5
r(1qfay61Sb206: gate, z+3 total・-'
5rQHCa, 73Sb2o: Mn"34"
--'Sr6. ia, ((Sbz 06: MnZt
-35---Sr(@73Ca, 7.ySb, 06
: Mn36---Zn4Si04:Mn, As37
-=Zn3(PO4)2 :Mn2+38--ZnS:
Ag, Cl

Claims (1)

[Claims] 1) In a color display tube having a luminescent screen in which phosphors emitting red, green, and blue light are painted in independent patterns, the blue luminescent phosphor has a composition formula: (Sr_1_-uCa_u)_1_-_vMn_vSb
A color display tube characterized in that it contains 50% or more of a phosphor having the following formula:_2O_6, where 0≦u≦0.15 0.03≦v≦0.3.