JPH0259192B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Application Field] The present invention relates to a picture tube mainly used for color monitor televisions, and particularly to a picture tube in which the blue phosphor has a long afterglow. [Prior Art and Problems to be Solved by the Invention] 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 60Hz, 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
It's down 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. Phosphors that meet these conditions include P-27 as a red phosphor and P-39 as a green phosphor and are in practical use, but they do not have sufficient afterglow as a blue phosphor. Nothing with this characteristic has been found. The blue afterglow phosphor used in long afterglow color picture tubes does not have the necessary afterglow characteristics on its own, so a red afterglow phosphor is used in addition to the P-22 blue phosphor, which has less afterglow characteristics. and a green afterglow phosphor are usually mixed in a ratio of about 1:1:1. 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.
With a y value of 0.22, an x value of 0.147, y for P-22 blue phosphor
Compared to the value of 0.051, it emits a blue color that is much closer to white. Therefore, in conventional color picture tubes using light blue, those with a long afterglow have the disadvantage that the blue emitted color approaches white, resulting in a narrow color reproduction range. Therefore, as a result of various studies on the manganese-activated calcium fluoride phosphor, which is a blue phosphor, the present inventors decided to add zinc in addition to manganese in the manufacturing process of this phosphor. As a result, we succeeded in increasing the luminance of light emission, extending the afterglow, and improving the deterioration caused by electron beam irradiation. The purpose of the present invention is to have a long afterglow and a wide color reproduction range.
It is an object of the present invention to provide a picture tube having a long afterglow phosphor that has high emission brightness and little deterioration under electron beam irradiation. [Means for Solving the Problems] That is, the present invention provides a picture tube in which a calcium fluoride long-afterglow blue-emitting phosphor activated with manganese and zinc is used as a phosphor. The activation amount of zinc is 0.07 to 7 parts by weight per 100 parts by weight of calcium fluoride, and the activation amount of zinc is 0.07 to 7 parts by weight per 100 parts by weight of calcium fluoride,
It relates to a picture tube having a content of 0.0002 to 2 parts by weight. The long afterglow blue-emitting phosphor used in the picture tube of the present invention has calcium fluoride as its matrix and is activated with both manganese and zinc. The activation amount of manganese 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 parts by weight. However, in the present invention, the manganese activation amount of the blue phosphor is 0.07 to 100 parts by weight of calcium fluoride.
Specify 7 parts by weight. Even if the activation amount of manganese is above or below the optimum range, the luminance tends to decrease and the afterglow time tends to shorten. Further, the activation amount of zinc is specified to be 0.0002 to 2 parts by weight. The activation amount of zinc is also similar to that of manganese.
If the amount is too high or too low, the luminance will decrease and the afterglow time will shorten. The activation amounts of zinc and manganese are determined to be within the previous range based on the luminance, afterglow time, and color of the luminescence. Embodiments The picture tube of the present invention is characterized in that a novel phosphor is used as the blue phosphor. The red phosphor and the blue phosphor include P, which has already been developed.
-27, P-39, or any new phosphors to be developed can also be used. Therefore, the blue phosphor will be described in detail below. 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 blue phosphor will be explained in more detail below. [Example 1 of blue phosphor] To 100 parts by weight of calcium fluoride, 1.5 parts by weight of manganese carbonate, 0.5 parts by weight of zinc carbonate, and 8 parts by weight of ammonium fluoride were weighed, and then heated in an alumina ball mill for 3 hours. 50g of the mixed powder obtained by mixing was placed in a crucible and fired in the air at 950°C for 90 minutes. The obtained fired product is cooled and loosened,
The fired product, glass beads, and pure water were placed in a polyethylene bottle at a weight ratio of 1:1:1, and then beer milled for 15 hours. After that, after sieving the water with a nylon mesh, the fired product and pure water were placed in a beaker at a weight ratio of 1:20, stirred for 30 minutes, and the fired product was allowed to settle for about 30 minutes, and the top was discarded. filtration, drying,
A phosphor powder was obtained by sieving. [Example 2 of blue phosphor] 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. , mixed thoroughly for 20 minutes. The obtained mixed powder was subjected to the same process as in Example 1 to obtain a phosphor powder. [Example 3 of blue phosphor] After weighing 0.8 parts by weight of manganese fluoride, 0.3 parts by weight of zinc fluoride, and 7 parts by weight of ammonium fluoride based on 100 parts by weight of calcium fluoride, Example 1 was prepared. A phosphor powder was obtained through the same process. [Comparative example of blue phosphor] A phosphor that is not activated by zinc was produced by removing zinc carbonate from Example 1, using the other mixed components, and using 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. In contrast, zinc is considerably lost during the firing process;
A few PPM to 100 PPM remains and activates calcium fluoride. Below, the characteristics of the phosphors obtained in these Examples are shown in Tables 1 to 3 in comparison with conventional phosphors. Table 1 shows the relative luminance for a conventional P-22 phosphor with almost no afterglow. Table 2 shows the afterglow times for the long afterglow P-27 red phosphor. Table 3 shows the brightness reduction rate of the phosphor of the present invention, which is a calcium fluoride blue phosphor activated only with manganese. The electron beam irradiation conditions for creating Table 3 were an accelerating voltage of 15 KV and a current of 10 μA/cm ^2.

【table】

【table】

〔Effect of the invention〕

In the picture tube of the present invention, a calcium fluoride long afterglow phosphor activated with manganese and zinc is used as the phosphor. In addition to having a long afterglow, this long afterglow phosphor emits a desirable blue color. Therefore, in the case of a color picture tube, despite having a long afterglow property, the color reproduction range can be widened, and the afterglow color itself can be made bluer, which is more preferable than the conventional light blue phosphor. In addition, in the case of monochrome picture tubes, the emission color and afterglow color during electron beam irradiation can be approximated, and the blue phosphor has a number of practical advantages such as high emission brightness and little deterioration under electron beam irradiation. Equipped with.

[Brief explanation of drawings]

The figure is a graph showing the color points of a phosphor used as a phosphor in the picture tube of the present invention and a conventional phosphor.

Claims (1)

[Claims] 1. The phosphor includes a calcium fluoride long afterglow phosphor activated with manganese and zinc, and the phosphor has a manganese activation amount of 100 parts by weight of calcium fluoride. 0.07 to 7 parts by weight, and the activation amount of zinc is 0.0002 parts by weight per 100 parts by weight of calcium fluoride.
2 parts by weight. 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 picture tube according to claim 1, wherein the amount is 0.0005 to 0.1 part by weight. 3 Blue phosphor, calcium fluoride long afterglow blue emitting phosphor activated with manganese and zinc, and P-
2. The picture tube according to claim 1, wherein a mixture of 22 and 22 blue phosphors is used. 4 The red phosphor is P-27 and the green phosphor is P-39.
A color picture tube according to claim 1.