JPS5956481A - Combined phosphor - Google Patents

Abstract

PURPOSE:To provide a combined phosphor emitting in the yellow, orange, etc. of high purity and having a preferrable afterglow property of 10-20msec in afterglow time, by incorporating borates of indium, yttrium and europium having a specific compsn. formula. CONSTITUTION:A Eu-activated indium borate phosphor or Eu-activated indium yttrium borate phosphor having a compsn. formula as shown (wherein x, y are 0<=x<=0.60, 0.005<=y<=0.30, respectively) and one or more different phosphors free from cadmium are mixed to yield combined phosphor. The emission of said phosphor under excitation by electron beam has an effective 10% afterglow time of 10msec or above and a chromaticity within a region surrounded by three straight lines on the CIE chromaticity coordinate: x=0.6, y=x+0.05, and a straight line connecting point A (x=0.60, y=0.39) with point B (x=0.44, y=0.49) and by a spectrol locus on the CIE chromaticity diagram.

Description

[Detailed description of the invention] [Technical field to which the invention pertains] The present invention relates to phosphors for cathode ray tubes, especially terminal display buttons. This invention relates to improvement of a light body suitable for cathode ray tubes.

[Technical background and problems]

Recently, with the spread of computers, many cathode ray tubes for displaying terminals have come into use. Among these, cathode ray tubes for orange monochrome display are widely used, especially in Europe and other countries, because their emitted light color is less tiring on the eyes and easier to see.

Although it has such characteristics, the above-mentioned cathode ray tube has the following drawbacks. That is, when the number of images displayed per second (frame frequency) is low, a flicker phenomenon occurs on the displayed screen, which gives an extremely unpleasant feeling. For example, in Japan and the United States, the above-mentioned frame frequency is usually 60H2, which causes relatively little flicker, but in Europe, this is as low as 53Hz, and in this case, the flicker phenomenon that affects the eyes is strong and is a practical problem. . Furthermore, in both Japan and Europe, the use of frame frequencies of 5Q Hz or lower is being considered for high-definition display cathode ray tubes.

In order to alleviate this flicker phenomenon, the above-mentioned phosphor is improved. This is the specific luminescence time (
The goal is to lengthen the afterglow. The longer the afterglow time is, the more the above-mentioned flicker will be alleviated, but if it is too long, various problems will remain, so it is necessary to keep the afterglow characteristic to an appropriate level.

The flickering sensation on the screen of a cathode ray tube depends on the afterglow characteristics of the phosphor screen and the brightness of the screen.
According to Vol. 19, page 19 (+980), for phosphors whose luminescence is given as the sum of several luminescent components,
When evaluating the degree of flicker, 10% of each luminescent component
The effective 10-chi afterglow time obtained by weighting the afterglow time according to the brightness of each component, and τeff obtained by It has been shown that the frame frequency is 5Q Hz.

It is noted that at standard display brightness, flicker does not occur if the afterglow time of 10 ts is longer than 0.6 milliseconds of the phosphor P22(a). Furthermore, according to Japanese Patent Application Laid-Open No. 55-124931, the ratio of the emission intensity I(T) at the end of one field to the average emission intensity within one field, which is determined by the following formula, is 0.15, that is, when the frame frequency is Hz, In some cases, it has been shown that phosphors with a 10% afterglow time of 15 milliseconds or more are effective in reducing flicker. From the example, the effective 10% afterglow time is 10 milliseconds,
Flicker can be reduced if the time is preferably 15 milliseconds or more. Furthermore, if the afterglow time is 20ms or more, 5
Flicker reduction is also possible in high definition display tubes with frame frequencies below QHz.

For this reason, in the past, phosphors (Cd, Cj(PO4), :D, (compositional formula n)) having high color purity and favorable characteristics such as the above-mentioned 10-chip afterglow time of 25 ms have been used. Although this phosphor has the above-mentioned properties, it contains cadmium, which is a harmful substance, as a component of the phosphor (F611), and it is preferable to avoid the use of cadmium from the viewpoint of pollution prevention.

[Purpose of the invention]

The present invention improves the above points and produces a yellow color with high color purity.

[Summary of the invention]

Yes, the compositional formula of the present invention is (,1,nl-X-yyxbuy
) BOs However, in the formula, C,)
It is obtained by mixing a europium-activated indium borate phosphor or a europium-activated indium borate phosphor with one or more other cadmium-free phosphors, and it emits light under electron beam excitation. C.I.
Direct #X=0 on the B chromaticity coordinate. L straight line y=X+0.
05 and point A in color fart coordinates (x=0.60,
y=0.39) and point B(x-0,44t'I=
0.49 ) and has a chromaticity within the area surrounded by the three straight lines connecting them and the spectral locus on the chromaticity diagram,
This is a mixed phosphor characterized by an effective 10% afterglow time of 10 milliseconds or more. That is, one of the phosphors is based on europium activated indium borate or europium activated indium yttrium borate phosphor, and this phosphor has a peak wavelength around 590 nm and is disclosed in Japanese Patent Application Laid-Open No. 57-51783. It is described in detail in the publication.

This phosphor (In1-x-y Yx Euy)BO3 emits orange light, and its chromaticity is located at point A at X=0.60, y=0.39 in the CIE chromaticity coordinates of Figure 1. do. By the way, by mixing this orange phosphor with other phosphors, it is possible to obtain a mixed phosphor that has an intermediate color between the emission colors of these phosphors alone, but when considering the emission color, CIE chromaticity coordinates In the case of
>X + 0.05, the color becomes greenish, and furthermore, in the area below and to the left of the straight line connecting points A and B, the color becomes whitish and the purity of the color decreases. For this reason, for yellow or orange with high color purity, the chromaticity region shown by diagonal lines in Figure 1 is desirable, and the chromaticity is to the upper right of the straight line connecting point A and point B in Figure 1. A phosphor that emits green or yellow light and the above phosphor (In,
x-y yxEuy) By mixing with BOs,
A mixed phosphor having an emission color within the above chromaticity range is obtained.

〔Effect of the invention〕

This mixed phosphor exhibits an effective 10% afterglow time of about 10 ms or more as defined above, and can sufficiently alleviate flicker on the screen of a cathode ray tube operating at 50 Hz. It can be applied as a phosphor for cathode ray tubes in the 5QHz range or high-titla cathode ray tubes, and the luminescent color efficiently emits yellow to orange with high color purity, which is the intended purpose of alleviating eye fatigue. At the same time, it became possible to obtain clear images.

Furthermore, the phosphor does not contain Cd, is safe, and poses no danger of public harm.

[Embodiments of the invention]

Example 1 As an orange phosphor, (In Y Bu )BO3, i.e., 1-X −)' After mixing thoroughly, the mixture was placed in a quartz crucible, maintained at about 1000°C to 1400°C in air, and heated and fired for about 1 to 5 hours to form (In O, 96Eu O, 04) B.
A phosphor called og was obtained.

This phosphor was formed in advance. Zn, 5i04 medium M
n pigeon-activated zinc silicate phosphor (green luminescence) and 98
: 2 (i amount ratio) to form a mixed phosphor. When a cathode gland tube for a computer was formed using this mixed phosphor and emitted light, it exhibited an orange color with high color purity, and the effective 10-channel afterglow time showed an excellent value of about 16 msec.

Similarly, various mixed phosphors, ie, the combinations of mixed phosphors in Examples 2 to 10 shown in Table 1, were used for the cathode ray tube, and the results were measured.

(Left below) In addition to this example, (In t-x, YxFiu,)
InBO3:T as a partner to be mixed with BO3 phosphor
bGd, 0. Terbium activated green phosphor such as S:Tb, Y2SiO, :Tb, cerium activated green phosphor such as CaS:Ce, manganese activated green or yellow phosphor such as Zn, 8i04:Mn, As, zinc sulfide type Even if it is mixed with a green phosphor or the like, the purpose of the present invention can be achieved without losing the spirit of the present invention.

[Brief explanation of the drawing]

FIG. 1 is a CIE chromaticity diagram showing the luminescent colors of the phosphor of the present invention. Representative Patent Attorney Kensuke Norichika (1 idiot)

Claims (1)

[Claims] The composition formula is (Eng n1-x-yYxEuy)Bo3 However, X and y in the formula are O≦X≦0.60, respectively.
Obtained by mixing a europium-activated indium borate phosphor or a europium-activated indium/yttrium borate phosphor such that 0.005≦y≦0.30 and one or more other cadmium-free phosphors. , the emission under electron beam excitation is on the Cll1ii chromaticity coordinates as a straight line X=
0.6. straight line) r = X, -0,05 and point A in chromaticity coordinates (x = 0.60, y = 0.39
) and point B (x=0.44, )'=0.49), and the effective 10 %
A mixed phosphor characterized by an afterglow time of 10 milliseconds or more.