JPH07116430B2 - Long afterglow blue-emitting mixture phosphor - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a long-afterglow blue light-emitting phosphor forming a part of a fluorescent film of a color cathode ray tube for a display device, and particularly to a long-afterglow fluorescence. The present invention relates to a long-afterglow blue light-emitting phosphor obtained by mixing a body and a short-afterglow phosphor.

[Prior Art and its Problems] Generally, in a color cathode ray tube used for a display device such as characters or figures, the scanning speed of an image is 2 to 2 times higher than that of a general color television cathode ray tube in order to increase resolution.
It is known to slow down more than three times. In this case, it is necessary that the phosphor used for the cathode ray tube-shaped phosphor film for a display device has a long afterglow property. Because
This is because if the fluorescent film of the cathode ray tube is composed of a phosphor having a short afterglow, the scanning speed of the fluorescent film is slow, and thus flicker occurs on the screen.

Usually, 1 × 10 5 afterglow time, that is, 10% afterglow time is used to display the afterglow of a phosphor. The 10% afterglow time is the time during which the emission brightness drops to 1/10 of the initial emission brightness after the excitation of the electron beam is stopped. In order to prevent screen flicker, the phosphor used in the fluorescent film of the cathode ray tube for display devices has a long afterglow that is tens to hundreds of times that of phosphors used in ordinary color television cathode ray tubes. Required to have.

Incidentally, as is well known, the fluorescent film of the color cathode ray tube is composed of green, blue and red light emitting phosphors. Manganese- and arsenic-activated zinc silicate phosphors are known as long-afterglow green-emitting phosphors, and manganese-activated magnesium fluoride phosphors and manganese are known as long-afterglow red-emitting phosphors. An activated zinc magnesium orthophosphate phosphor is known.

On the other hand, as the long-afterglow blue-emitting phosphor, for example, a silver-activated zinc sulfide phosphor represented by the general formula: ZnS: Ag, Ga, X (where X is a halogen element or aluminum), It is proposed in JP-A-58-79814. Further, indium (I) was used as the first coactivator instead of gallium (Ga).
A silver activated zinc sulfide phosphor similar to that described above is proposed in Japanese Patent Application Laid-Open No. 58-83084, etc.

However, it is difficult to say that this silver-activated zinc sulfide phosphor is sufficiently practical as compared with the green and red phosphors. That is, the above-mentioned silver-activated zinc sulfide phosphor has a problem that the emission brightness is low, and the brightness saturation characteristic and the burning characteristic (film burn) due to the current density are poor in the coating film of the cathode ray tube. This is because generally, if afterglow is imparted, from the relationship between excitation energy and emission energy, the brightness inevitably decreases as the afterglow becomes longer, and a large number of co-activators should be introduced into the phosphor matrix. The reason is that extra impurities are put in the crystal lattice of the phosphor to forcibly create lattice defects, so that the luminance saturation characteristic and the burning characteristic due to the current density are inevitably deteriorated.

As described above, there is no practical long-afterglow blue-emitting phosphor made of a single phosphor, and in order to achieve high brightness, for example, as shown in Japanese Patent Publication No. 57-37098. To
A long afterglow blue-white luminescent mixture phosphor by mixing a short afterglow blue light-emitting phosphor as a main light emitting component and a green or red long afterglow phosphor that is an emission color other than blue light emission. Can be obtained.

However, in this mixture phosphor, the emission color after the excitation is stopped, that is, the problem of color shift that the afterglow color is not blue,
In addition, there is a problem of uneven color and deterioration of color purity due to mixing of the phosphors.

[Object of the Invention] The present invention has been made in view of the above circumstances.
The object is to provide a long-afterglow blue-light-emitting mixture phosphor that is excellent in emission luminance and color purity of emission color, does not cause color shift of afterglow color, and has excellent luminance saturation characteristics and burning characteristics due to current density. To do.

[Summary of the Invention] The present inventors have proposed in Japanese Patent Application No. 60-225886 a self-activated zinc sulfate phosphor having long afterglow as a high emission brightness type.

In improving the long-afterglow blue-light-emitting mixture phosphor, the present inventors firstly used CIE as a long-afterglow blue-light-emitting phosphor.
By selecting a self-activated zinc sulfide phosphor that exhibits a deep blue emission color and high emission luminance in the chromaticity coordinate, and then introducing a large amount of a silver activator into the zinc sulfide matrix, the luminance saturation characteristics depending on the current density can be obtained. And a short afterglow blue-emitting phosphor having improved burning characteristics, by mixing an appropriate amount of the self-activating blue-emitting phosphor, an ideal afterglow blue phosphor is newly obtained. I found it.

That is, the above-mentioned object is that the first coactivator is at least one of tin, lead, thallium, indium, gallium, arsenic, antimony, bismuth, and europium, and the second coactivator is fluorine, Chlorine, bromine, iodine and a long afterglow blue-emitting phosphor made of self-activated zinc sulfide that is at least one of aluminum, and the activator is silver, the co-activator is fluorine, chlorine, bromine, It is at least one of iodine and aluminum, contains 300 ppm or more of silver as an activator, and the co-activator is 1 × 10 ^−2, which is 1 × 10 ⁻⁶ wt% of the phosphor matrix. A solution is provided by providing a long-afterglow blue-light-emitting mixture phosphor characterized by being a mixture with a short-afterglow blue-light-emitting phosphor made of silver-activated zinc sulfide in a weight% range. .

Since the activation amount of silver of the short afterglow blue light emitting phosphor is 300 ppm or more, the emission brightness saturation property and the burning property due to the current density are extremely improved in this short afterglow blue light emitting phosphor.

In addition, the co-activation amount of this short afterglow blue light emitting phosphor is 1 above.
× impractical from the point or the like of the emission luminance also too much too small than a range from 10 ^-6% by weight of 1 × 10 ^-2 wt%.

The matrix of the short afterglow blue light emitting phosphor of the present invention may be either cubic or hexagonal crystal form zinc sulfide.
Cubic zinc sulfide is produced when sintering is performed at a sintering temperature of 1050 ° C. or lower, and in this case, an activator and a co-activator are introduced in a very large amount in the phosphor matrix. On the other hand, hexagonal zinc sulfide is produced when firing at a firing temperature of 1050 ° C or higher, and in this case, the amount of the activator and co-activator introduced into the matrix is higher than that of cubic zinc sulfide. Less.

Also, preferably, the short afterglow blue-light-emitting phosphor and / or the long afterglow blue-light-emitting phosphor according to the present invention is at least one of boron, silicon, phosphorus and cerium for further improving the burning characteristics. It is preferable that a small amount of a compound containing one element is contained.

Further, on the surface of the phosphor particles of the long afterglow blue light emitting phosphor and the short afterglow blue light emitting phosphor which constitute the mixture phosphor of the present invention, blue pigment particles such as cobalt blue and ultramarine blue are preferable. The phosphor may be coated with 0.5 to 6% by weight.

[Operation and Effect of the Invention] In the persistence blue light-emitting mixture phosphor of the present invention, the conventional silver-activated zinc sulfide phosphor and the emission color other than blue in the coating film of the cathode ray tube during electron beam stimulation. Compared with the mixture phosphor in which the afterglow phosphor is mixed, the emission brightness, the emission brightness saturation characteristic according to the current density, and the burning characteristic are excellent.

Further, in the phosphor of the present invention, since the short afterglow phosphor and the long afterglow phosphor have the same blue emission color, the residual phosphor of the mixture obtained by mixing the afterglow phosphors of emission colors other than blue Although the light color is not blue, an afterglow color that is almost the same as the emission color is obtained.

Further, according to the present invention, a long afterglow blue light emitting mixture phosphor showing a deeper blue color than the long afterglow blue light emitting phosphor consisting of only the single self-activated zinc sulfide phosphor can be obtained. This is because the short afterglow phosphor emits deeper blue light than the long afterglow blue light emitting phosphor.

Examples Example 1. As a long afterglow blue light-emitting phosphor, 3.2 × 10 ⁻⁴ wt% tin (Sn) with respect to a zinc sulfide matrix and 1 × 10 ^{−4 with} respect to a zinc sulfide matrix. Self-activated zinc sulfide phosphors were used, each containing 1 wt.% Chlorine (Cl) as the first and second co-activators.

In the powder characteristics of this long afterglow blue light emitting phosphor, the x value and y in the CIE chromaticity coordinate indicating the emission color
The values are 0.145 and 0.137 respectively, the Y value that mainly indicates the emission luminance is 51.5%, the 10% afterglow time is 48 ms, and the luminance saturation characteristic due to the current density is 0.5 μA / cm ^{2 at} the current density. The emission luminance at a current density of 5 μA / cm ² was 60% with reference to the emission luminance of. The burning characteristic value is 70%.
And this value was measured as follows. That is, after the phosphor is deposited on quartz glass by spraying with acrylic lacquer and metal back is applied, 27 kv, measured with reference to the emission brightness of the coating film with an electron beam of 0.5 μA / cm ² , 27 kv,
After forcibly deteriorating with an electron beam of 20 μA / cm ² for 30 minutes, the emission brightness of the coating film was measured.

On the other hand, as a short-afterglow blue-emitting phosphor, 3.0 × 10 ^-3 % by weight of silver (Ag) was activated in a large amount with respect to the zinc sulfide matrix, and the zinc sulfide matrix was used as a co-activator. For 1 x 10
A cubic silver activated zinc sulfide phosphor containing ^-3 % by weight of chlorine (Cl) and 1 × 10 ^-4 % by weight of cerium (Ce) for improving the burning characteristics was used. In the powder characteristics of this cubic short afterglow blue light-emitting phosphor, the x value and the y value in the CIE chromaticity coordinate indicating the emission color are 0.147 and 0.056, respectively, and Y that mainly indicates the emission brightness is shown.
The value is 90%, the 10% afterglow time is 1.6ms, and the brightness saturation characteristic by current density is based on the emission brightness at a current density of 0.5μA / cm ² and the light emission at a current density of 5μA / cm ^2. 80% brightness
Met. The burning characteristics measured as described above were 93%.

These long-afterglow and short-afterglow blue-emitting phosphors, respectively
500 g of the mixture was thoroughly mixed in a dry system to obtain a long afterglow blue light emitting mixture phosphor of the present invention.

In the thus obtained mixture phosphor, the x value and the y value in the CIE chromaticity coordinate indicating the emission color are 0.150 respectively.
And 0.068, the Y value which mainly indicates the emission luminance is 78%, the 10% afterglow time is 38 ms, and the luminance saturation characteristic due to the current density shows the emission luminance at the current density of 0.5 μA / cm ^2. As a reference, the emission luminance at a current density of 5 μA / cm ² was 40%. The burning characteristic value measured in the same manner as above is 97.
%Met.

Example 2. The long afterglow blue light emitting phosphors include 4.5 × 10 ⁻⁴ wt% gallium (Ga) based on the zinc sulfide matrix and 1.2 × 10 ⁻² wt% based on the zinc sulfide matrix. Self-activated zinc sulfide phosphors containing bromine (Br) as the first and second coactivators were used. Incidentally, in the powder characteristics of this long afterglow blue emission luminance phosphor, the x value and the y value in the CIE chromaticity coordinate indicating the emission color are 0.147 and 0.136, respectively, and the Y value mainly indicating the emission luminance is 56.5. %, The 10% afterglow time is 40 ms, and the brightness saturation characteristic due to the current density is
5μA / based on the emission brightness at a current density of 0.5μA / cm ²
The emission luminance at a current density of cm ² was 50%. The burning characteristic value is 60%.

On the other hand, as the short-afterglow blue-emitting phosphor, a large amount of 6.0 × 10 ⁻³ wt% silver (Ag) was added to the zinc sulfide matrix,
A cubic crystal containing 1 × 10 ^-3 % by weight of aluminum (Al) as a co-activator with respect to the matrix of zinc sulfide and 1 × 10 ^-4 % by weight of silicon (Si) for improving the burning characteristics. A silver-activated zinc sulfide phosphor phosphor of the system was used.
Incidentally, in the powder characteristics of this short afterglow blue light emitting phosphor, the x value and the y value in the CIE chromaticity coordinates indicating the emission color are 0.148 and 0.058, respectively, and Y mainly showing the emission brightness is shown.
Value was 85%, 10% decay time is 2.0 ms, the luminance saturation characteristics of current density, at a current density of 5 .mu.A / cm ² based on the light emission luminance at a current density of 0.5 .mu.A / cm ² The emission brightness was 83%. The burning characteristic value was 91%.

These long afterglow and short afterglow blue light emitting phosphors are respectively
600 g and 400 g were thoroughly mixed by a dry method to obtain a long afterglow blue light emitting mixture phosphor of the present invention.

In the thus-obtained mixture phosphor, the x value and the y value in the CIE chromaticity coordinates indicated by the luminescent color are 0.148 and 0.078, respectively, and the Y value that mainly indicates the emission luminance is 70% and 10%. afterglow time is 30 ms, the luminance saturation characteristics with respect to current density of the light emission luminance at a current density of 5 .mu.A / cm ² based on the light emission luminance at a current density of 0.5 .mu.A / cm ² was 35%. The burning characteristic value was 96.5%.

This phosphor can adjust the afterglow time by changing the activation amount of gallium (Ga). Fig. 1 shows 10 against the activation amount of gallium.
% Changes in afterglow time and current characteristics are shown. As shown in this figure, as the activation amount of gallium increases, the afterglow time becomes longer and the current characteristics deteriorate. Therefore, the activation amount of gallium is determined to be an optimum value in consideration of the required afterglow time and current characteristics. Normally gallium activation amount is 120ppm
Adjusted to:

Example 3. As a long afterglow blue-emitting phosphor, 6.0 × 10 ⁻⁴ wt% of lead (Pb) based on zinc sulfide matrix and 1 × 10 ⁻⁴ wt% based on zinc sulfide matrix. Self-activated zinc sulfide phosphors containing bromine (Br) as the first and second coactivators were used. Incidentally, in the powder characteristics of this long afterglow blue-emitting phosphor, the x value and the y value in the CIE chromaticity coordinate indicating the emission color are 0.147 and 0.141, respectively, and the Y value mainly indicating the emission luminance is 55.0. %, 10% afterglow time is 60%
The brightness saturation characteristic according to the current density is 0.5 μA / cm ²
The light emission luminance at a current density of 5 μA / cm ² was 53% based on the light emission luminance at a current density of 5%. The burning characteristic value is 65%.

On the other hand, as a short-afterglow blue-emitting phosphor, 2.0 × 10 ^-3 % by weight of silver (Ag) was activated to a zinc sulfide matrix, and a zinc sulfide matrix was used as a co-activator. A hexagonal silver activated zinc sulfide phosphor containing 1 × 10 ⁻³ wt% aluminum (Al) and 1 × 10 ⁻⁴ wt% phosphorus (P) for improving the burning characteristics was used. . In the powder characteristics of this short afterglow blue light emitting phosphor, the x value and the y value in the CIE chromaticity coordinate indicating the emission color are 0.148 and 0.060, respectively, and the Y value mainly indicating the emission luminance is 88%. , and the 10% decay time is 2.0 ms, the luminance saturation characteristics with respect to current density of the emission luminance at a current density of 5 .mu.A / cm ² based on the light emission luminance at a current density of 0.5 .mu.A / cm ² 85 %Met. The burning characteristic value was 90%.

These long afterglow and short afterglow blue emission brightness phosphors, respectively
400 g and 600 g were thoroughly mixed by a dry method to obtain a long afterglow blue light emitting mixture phosphor of the present invention.

In the thus-obtained mixture phosphor, the x value and the y value in the CIE chromaticity coordinate indicating the emission color are 0.151 and 0.055, respectively, and the Y value that mainly indicates the emission luminance is 78% and 10%. afterglow time is 36 ms, the luminance saturation characteristics with respect to current density of the light emission luminance at a current density of 5 .mu.A / cm ² based on the light emission luminance at a current density of 0.5 .mu.A / cm ² was 48%. The burning characteristic value was 97.4%.

Example 4. The same long-afterglow and short-afterglow phosphors as in Example 1 were used, respectively.
After thoroughly mixing 0 g, 1.5% by weight of cobalt blue blue pigment particles with respect to the phosphor was adhered to the surface of these phosphor particles to obtain the phosphor of the present invention.

In the thus-obtained mixture phosphor, the x value and the y value in the CIE chromaticity coordinate indicating the emission color are 0.148 and 0.060, respectively, and the Y value that mainly indicates the emission luminance is 50% and 10%. afterglow time is 28 ms, the luminance saturation characteristics with respect to current density of the light emission luminance at a current density of 5 .mu.A / cm ² based on the light emission luminance at a current density of 0.5 .mu.A / cm ² was 41%. The burning property was 97%.

[Brief description of drawings]

FIG. 1 is a graph showing current characteristics and afterglow characteristics with respect to the activation amount of Ga, and FIG. 2 is a change in x value and y value with respect to a mixing ratio of short afterglow blue light emitting phosphor and long afterglow blue light emitting phosphor. FIG. 3 is a graph showing changes in current characteristics and burning characteristics with respect to the mixing ratio of the short afterglow blue light emitting phosphor and the long afterglow blue light emitting phosphor.

Claims (4)

[Claims] 1. The first coactivator is at least one of tin, lead, thallium, indium, gallium, arsenic, antimony, bismuth and europium, and the second coactivator is fluorine or chlorine. , A long afterglow blue-emitting phosphor made of self-activated zinc sulfide which is at least one of bromine, iodine and aluminum, and the activator is silver, and the co-activator is fluorine, chlorine, bromine, iodine. And at least one kind of aluminum, which contains 300 ppm or more of silver as the activator, and the coactivator is 1 × 10 ⁻⁶ wt% to 1 × 10 ⁻ % with ^respect to the matrix of the phosphor. ^A long-afterglow blue-emitting mixture phosphor, which is a mixture with a short-afterglow blue-emitting phosphor consisting of silver-activated zinc sulfide in the range of ² % by weight. 2. The long afterglow blue light emitting mixture phosphor according to claim 1, wherein the matrix of the short afterglow blue light emitting phosphor is made of cubic zinc sulfide. . 3. The long afterglow blue light emitting mixture phosphor according to claim 1, wherein the matrix of the short afterglow blue light emitting phosphor is made of hexagonal zinc sulfide. . 4. The short afterglow blue light emitting phosphor and / or the long afterglow blue light emitting phosphor contains a compound containing any one element of boron, silicon, phosphorus and cerium. The long afterglow blue light emitting mixture phosphor according to claim 1.