JPH0259191B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a long afterglow blue phosphor mainly used in cathode ray tubes for color monitor televisions. A. Prior Art Recently, high-definition display color picture tubes have been widely used for observation of terminal equipment of electronic computers and system control equipment. The vertical scanning frequency of a normal color television is 60 Hz, but in order to further improve the resolution, high-definition monitor televisions raise the horizontal scanning frequency and increase the number of scanning lines.
As the horizontal scanning frequency increases, video amplifiers are required to have a wide frequency response and become significantly more expensive.
By lowering the vertical scanning frequency, the frequency characteristics of the video amplifier can be narrowed. Therefore, the vertical scanning frequency is usually lowered to about 40Hz. In order to prevent screen flickering at this time,
It is necessary that the phosphor forming the fluorescent surface has a long afterglow. As phosphors that meet these conditions, P-27 is known as a red phosphor, and P-39 is a green phosphor, which are in practical use.
No blue phosphor having sufficient afterglow properties has been found. Since the blue afterglow phosphor does not have the necessary afterglow characteristics on its own, a red long afterglow phosphor and a green long afterglow phosphor are mixed with the P-22 blue phosphor. . This phosphor has the disadvantage that the blue phosphor is mixed with red and green phosphors for the purpose of increasing the afterglow time, so the emitted light color is blue, which is close to white. This phosphor is called a long afterglow light blue phosphor, and its color point is approximately 0.24 in x value and 0.22 in y value, compared to 0.174 in x value and 0.051 in y value for P-22 blue phosphor. It emits a blue color that is quite close to white. B. Structure and purpose of the invention As a result of various studies on manganese-activated calcium fluoride phosphors, the present invention has decided to add zinc in addition to manganese in the manufacturing process of this phosphor. As a result, they succeeded in increasing the luminance of the emitted light, making the afterglow longer, and improving the deterioration caused by electron beam irradiation. An object of the present invention is to provide a long afterglow blue light-emitting phosphor that emits light in a color close to blue, has a long afterglow, has high luminance under electron irradiation, and has little deterioration. That is, the present invention is a calcium fluoride long afterglow blue-emitting phosphor activated with manganese and zinc, wherein the activation amount of the manganese is 0.07 to 7 parts by weight per 100 parts by weight of calcium fluoride. Department,
The present invention relates to a long afterglow blue-emitting phosphor characterized in that the activation amount of zinc is 0.0002 to 2 parts by weight per 100 parts by weight of calcium fluoride. The long afterglow blue-emitting phosphor of the present invention has calcium fluoride as its base material and is prepared by activating it with both manganese and zinc. is preferably in the range of 0.15 to 2 parts by weight. On the other hand, the activation amount of zinc is preferably in the range of 0.0005 to 0.1 part by weight. In the present invention, the activation amount of manganese is specified to be 0.07 to 7 parts by weight per 100 parts by weight of calcium fluoride. Even if the activation amount of manganese is greater or less than the optimum range, the luminance tends to decrease and the afterglow time tends to become shorter. The zinc activation amount is specified to be 0.0002 to 2 parts by weight. Similarly to manganese, if the zinc activation amount is too large or too small, the luminance will decrease and the afterglow time will become short. The activation amounts of zinc and manganese are specified within the above range based on the luminance of the luminescence, afterglow time, and color of the luminescence. C Example A calcium fluoride long-afterglow blue-emitting phosphor activated with manganese and zinc is produced in the following steps. First, a predetermined amount of manganese sources such as manganese carbonate, manganese acetate, and manganese fluoride, zinc sources such as zinc carbonate, zinc acetate, and zinc fluoride, and calcium fluoride as a matrix are weighed and mixed well. . After that, a predetermined amount of ammonium fluoride was added as a fluxing agent, and the mixture was placed in a quartz or alumina crucible and heated in the atmosphere at a temperature of 800°C to 1250°C.
Bake for an hour. After cooling this fired product, it is washed with water, dispersed, dried,
After sieving, the long afterglow blue emitting phosphor of the present invention is obtained. The amount of ammonium fluoride added during this firing is 1 part by weight per 100 parts by weight of calcium fluoride.
The amount is preferably 15 parts by weight. The present invention will be explained in more detail below based on examples. Example 1 A mixture obtained by weighing 1.5 parts by weight of manganese carbonate, 0.5 parts by weight of zinc carbonate, and 8 parts by weight of ammonium fluoride to 100 parts by weight of calcium fluoride, and then mixing the mixture in an alumina ball mill for 3 hours. 50g of the powder was placed in a crucible and fired at 950°C for 90 minutes in the air. The obtained fired product is cooled and loosened,
The fired product, glass beads, and pure water were placed in a beaker at a weight ratio of 1:1:1, and then bead milled for 15 hours. After that, after sieving the water with a nylon mesh, put the fired product and pure water in a beaker at a weight ratio of 1:20, stir for 30 minutes, let the fired product settle for about 30 minutes, and discard the top. A phosphor powder was obtained by filtration, drying and sieving. Example 2 2.5 parts by weight of manganese acetate, 1.2 parts by weight of zinc acetate, and 8 parts by weight of ammonium fluoride were weighed against 100 parts by weight of calcium fluoride, and then placed in a mortar and thoroughly mixed for 20 minutes. . The obtained mixed powder was subjected to the same process as in Example 1 to obtain a phosphor powder. Example 3 After weighing 0.8 parts by weight of manganese fluoride, 0.3 parts by weight of zinc fluoride, and further 7 parts by weight of ammonium fluoride to 100 parts by weight of calcium fluoride, the same steps as in Example 1 were carried out to form a powder. A luminescent powder was obtained. Comparative Example A phosphor that is not activated by zinc was produced by using the same method as in Example 1 except for zinc carbonate and using the other mixed components and the same manufacturing process as in Example 1. In Examples 1 to 3, most of the manganese remained without being burned out during the firing process. Therefore, Examples 1 to 3
The manganese activation amount of the phosphor produced by the method is about 0.4 to 0.7 per 100 parts by weight of calcium fluoride. On the other hand, a considerable amount of zinc is lost during the firing process;
A few PPM to 100 PPM remains and activates calcium fluoride. The characteristics of these phosphors are compared with conventional phosphors and are shown in Tables 1 to 3 below. Table 1 shows the relative luminance for a conventional P-22 phosphor with almost no afterglow. Table 2 shows the afterglow times of the P-27 red phosphor, which has a long afterglow time, and the phosphor of the present invention. Table 3 shows a comparison of the brightness reduction rate between the comparative example, which is a calcium fluoride phosphor activated only with manganese, and the phosphor of the present invention. The electron beam irradiation conditions for creating Table 3 were an accelerating voltage of 15 KV and 10 μA/cm ²
This shows the decrease in luminescence brightness when irradiated for 30 minutes at a current density of .

【table】

【table】

[Table] As is clear from the above results, the phosphor of the present invention is a long afterglow blue-emitting phosphor with a peak wavelength of 495 nm under electron irradiation, and its emission intensity is also that of a normal color TV. P-, which is used in
5~15% higher than 22 blue, afterglow characteristic is 170~190ms
It is very long. Furthermore, deterioration under electron beam irradiation is also improved compared to a calcium fluoride phosphor activated with only manganese. The long afterglow blue emitting phosphor according to the present invention has a high luminance under electron beam irradiation as shown in Tables 1 and 2, and has a particularly long afterglow. A phosphor with a long afterglow is obtained. The figure shows the color points of each phosphor. In the figure, point A is P-39 long afterglow green phosphor, point B is P-27
Point C is a long afterglow red phosphor, point C is a P-22 blue phosphor, point D is a light blue long afterglow phosphor, and point E is a long afterglow blue phosphor of the present invention obtained in Example 1. The points α, β, and γ of the phosphor of the present invention were obtained in Example 1, and the phosphor of the present invention was
Color points of long afterglow blue phosphor mixed with blue phosphor at 50%, 30%, and 10% by weight are shown. In the figure, the afterglow time of the long afterglow blue phosphor whose color points are α, β, and γ is as follows in the order of α, β, and γ.
It has sufficient afterglow properties of 150msec, 120msec, and 50msec, and emits a deeper blue color than conventional light blue long afterglow phosphors. Therefore, the blue long afterglow phosphor obtained by mixing the phosphor of the present invention with the P-22 blue phosphor has an afterglow time equivalent to that of the red and green long afterglow phosphors. Moreover, it emits deep blue light with a luminescent color close to P-22. This phosphor is P-39 for the green component and P-27 for the red component.
When used together, a suitable fluorescent surface of a color display picture tube can be constructed. Furthermore, although the phosphor of the present invention is not as bad as the P-22 blue phosphor in terms of deterioration due to electron beam irradiation, it is sufficiently improved and has a particularly long afterglow, so it is better than the P-22 blue phosphor.
When mixed with blue, only a small mixing ratio is required, and the degradation as a mixed blue component has become sufficiently practical. Furthermore, since the peak wavelength is 495nm,
It is also suitable for mixing with P-39, which emits green light, to produce a green component with a longer afterglow.

[Brief explanation of drawings]

The figure is a graph showing the color points of the phosphor of the present invention and a conventional phosphor.

Claims (1)

[Scope of Claims] 1. A calcium fluoride long afterglow blue-emitting phosphor activated with manganese and zinc, wherein the activation amount of the manganese is based on 100 parts by weight of calcium fluoride.
0.07 to 7 parts by weight, and the activation amount of zinc is 0.0002 to 2 parts by weight per 100 parts by weight of calcium fluoride.
A long-afterglow blue-emitting phosphor characterized by a weight part. 2 For 100 parts by weight of calcium fluoride, the activation amount of manganese is 0.15 to 2 parts by weight, and the activation amount of zinc is 0.15 to 2 parts by weight.
The long afterglow blue emitting phosphor according to claim 1, wherein the amount is 0.0005 to 0.1 part by weight.