JPH01223192A - Mixed fluorescent substances - Google Patents

Abstract

PURPOSE:To obtain a mixed fluorescent substance with prevents tone deviation caused by ultraviolet excitation and reduces color difference on the coated surface by mixing several kinds of fluorescent substances different in emission color, including fluorescent substances coated with inorganic blue pigment and other fluorescent substances emitting visible light by excitation with ultraviolet rays. CONSTITUTION:The subject mixed fluorescent substance is obtained by using several kinds of fluorescent substances different in emission color including a blue-emitting fluorescent substance coated with 0.01-10wt.% of a blue pigment such as cobalt aluminate and another fluorescent substance emitting visible light by excitation with ultraviolet rays. The fluorescent substance is used in cathode tubes for monochrome or colored displays.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to phosphors used in cathode ray tubes for monochrome or color displays.

[Prior Art and Problems] Recently, many cathode ray tubes have been used for displays such as computer terminal displays that display monochrome or color images, but the phosphors used in these tubes are blue, green, yellow,
It emits orange, red, and white light, and is captivated by a wide variety of colors. For example, by using a mixed phosphor that is a mixture of two to four component phosphors that emit different light, the emitted light colors can be adjusted to a wide variety of colors that cannot be emitted by a single phosphor.

However, although mixed phosphors emit bright light when excited by electron beams, many of them also emit light when excited by ultraviolet light. Cathode ray tubes stimulate phosphors with electron beams rather than ultraviolet light, and the phosphors are not directly excited by ultraviolet light.

However, the problem with mixed phosphors that include blue light phosphors is that the blue light emitting phosphor is excited by the electron beam and emits blue visible light, which is close to ultraviolet light, so it is excited by the purple border line. This excites other phosphors that emit light, causing them to emit light.

That is, a green-emitting phosphor that is a phosphor other than a blue-emitting phosphor,
Yellow-emitting phosphors, wide-color emitting phosphors, red-emitting phosphors, etc. are excited by electron beams and then re-excited by blue rays close to ultraviolet rays (herein referred to as rays in the ultraviolet region). It emits light again. As a result, there is a drawback that the powder color tone and afterglow time deviate from the characteristics required of a cathode ray tube.

Mixed phosphors excited by light in the ultraviolet region have a long afterglow time. This has the effect of reducing flicker. However, the color tone shift caused by ultraviolet light rays results in a color difference on the phosphor screen, and the emitted light color becomes non-uniform between the center and corners of the cathode ray tube.

The color difference of the phosphor is caused by the non-uniform coating state of the phosphor and the fact that the phosphor emits light when excited by ultraviolet light.

Efforts are being made to improve the coating conditions, exposure, development, etc. of cathode ray tube phosphor screens so that the coating amount at the center and corners is as uniform as possible. However, there is still a difference in the amount of coating between the center and the corners, and this cannot be completely eliminated.

When the phosphors in the phosphor film, which have different coating amounts, are re-excited by light in the ultraviolet region, the difference in the amount of light emitted by the phosphors other than the blue-emitting phosphors immediately appears as a color difference between the center and corners. come.

[Object of the present invention] The present invention was developed with the aim of solving this drawback, and an important purpose of the present invention is to prevent color tone shift due to light excitation in the ultraviolet region, and to improve the appearance of the phosphor-coated surface. The object of the present invention is to provide a mixed phosphor that can reduce the color difference.

[Means for Solving the Problem] In order to solve this problem, the inventors of the present invention have conducted various studies and found that a mixed phosphor in which a plurality of phosphors with different emission colors are mixed is effective in the ultraviolet region. By coating a blue-emitting phosphor that emits light with a blue inorganic pigment such as cobalt aluminate or ultramarine in an amount of 0.01-10% by weight relative to the blue-emitting phosphor, the blue inorganic pigment can be coated in the ultraviolet region. We succeeded in absorbing this light, and succeeded in reducing the color difference of the mixed phosphor caused by light excitation in the ultraviolet region.

When the amount of blue inorganic pigment attached is 0.01% by weight or less,
The effect of reducing color difference is small, and when 10% by weight or more is mixed, the luminance of light emission decreases. Therefore, the amount of the blue inorganic pigment deposited is adjusted within the above range, taking into account both color difference and luminance.

[Operation] Light in the ultraviolet region emitted from the blue phosphor included in the mixed phosphor is absorbed by the blue inorganic pigment attached to the blue-emitting phosphor.

If the mixed phosphor contains, for example, yellow, green, orange, and red phosphors, these phosphors are re-excited by radiation in the ultraviolet range emitted by the blue-emitting phosphor; A blue inorganic pigment such as cobalt aluminate or ultramarine blue attached to the blue phosphor prevents excitation by light rays.

As shown in the examples, in the mixed phosphor of the present invention, ΔX and Δy indicating color shift between the center and corner of the phosphor coating film are Δx=2/1000 to 3/1000, Δy=
This is a remarkable decrease of 2/1000 to 4/1000 compared to conventional mixed phosphors.

By the way, the conventional mixed phosphor has Δx=6/1000~
9/1000, Δy=8/1000 to 16/1000, which is several times larger than that of the mixed phosphor of the present invention, and the mixed phosphor of the present invention realizes excellent characteristics that surpass those of conventional mixed phosphors. .

[Preferred embodiment] Examples of the present invention will be described below.

(Example 1) First, the method for manufacturing the phosphor of the present invention will be described.

First, use the following materials.

Blue phosphor ZnS/Ag fist CA 490g cobalt aluminate 4.9g pure water
2.21L yellow phosphor (Zn-Cd) S/Cu-Ajl Mix 1510 g of the prepared blue phosphor ZnS/Ag-CIL with pure water. Cobalt aluminate is then added to the blue phosphor to coat it with a blue inorganic pigment.

Zn5iO3 is used as an adhesive to attach the inorganic pigment to the surface of the blue-emitting phosphor.

This Zn5iOa is produced by mixing K2S i Oa and Zn5Oa with pure water in which the blue-emitting phosphor and cobalt aluminate are mixed, and reacting the mixture to coat the surface of the phosphor.

K2SiO3 is added in an amount such that the teno concentration is 2% as SiO2, and Zn5Oa is added in an amount such that the concentration is 2% as Zn. When reacted in this state, 0.
2wt% Zn5iO3 coats the surface, which deposits the blue inorganic pigment.

After drying the obtained phosphor, this blue-emitting phosphor is
Yellow phosphor (ZnCd) S/Cu-Al1 is mixed to obtain a blue-yellow mixed phosphor.

This mixed phosphor is a mixture of a blue-emitting phosphor and a yellow-emitting phosphor, and the blue-emitting phosphor has cobalt aluminate deposited on its surface.

The characteristics of this phosphor as a phosphor film were measured using the following method.

First, prepare a 12 inch - 90 degree cathode ray bulb.

2.5 g of the obtained phosphor was added to 28% 2Si03 solution 8
A phosphor slurry is obtained by mixing 0 mA with 250 mjl of pure water and stirring for 30 minutes. As cushioning liquid, 50ml of 500ppm Ba(NO3)2 solution
The former slurry was added to a diluted version of JL with 30 volumes of water.

Glass plate sample pieces are placed in the center and corners of the cathode ray bulb to create a phosphor precipitate film on the glass surface.
After applying the lacquer film and metal back, bake at 450°C for 30 minutes. The obtained glass sample piece was placed in a demantaple CRT device at a voltage of 7 kV and a current density of 0.
5. Color tone is measured under the condition of uA/cm2.

The chromaticity coordinates, y value, and y value of the obtained mixed phosphor are x
=0.287, y=0.314.

As a result of measuring the color shift of the above mixed phosphor between the center and corner of the bulb, the difference is ΔX=3/1000,
It was extremely small, Δy=4/1000.

The conventional mixed phosphor produced under the same conditions as in Example 1 except that the surface of the blue-emitting phosphor was not coated with a blue inorganic pigment showed color fading at the center and corners of the bulb,
Δx=8/1000 and Δy=15/1000, and the mixed phosphor of the present invention had extremely reduced color shift compared to the conventional phosphor.

- Figure 1 shows the difference in the chromaticity diagram between the phosphor obtained in Example 1 according to the present invention and a conventional phosphor whose surface is not coated with a blue inorganic pigment. As is clear from this figure, the blue inorganic pigmented mixed phosphor of the present invention effectively suppresses the color shift of the yellow phosphor.

(Example 2) Use the following materials as materials.

Blue phosphor Y2S ios/Ce 400g Cobalt aluminate 1.6g Pure water
Magazine 1 yellow phosphor YaA
Using 600 g of AsOt2/Ce prepared as the i-material, a mixed phosphor is prototyped in the same process as in Example 1 except that the blue-emitting fluorescent material and the blue inorganic pigment adhesive are changed.

AQ2SiOs is used as the adhesive for attaching the blue inorganic pigment to the surface of the blue-emitting phosphor.

This AA2S iOs consists of K2SiO3 and A magazine 2 (S0
4) 3 is mixed with pure water in which the blue-emitting phosphor and cobalt aluminate are mixed, reacted, and coated on the surface of the phosphor.

K2SiO3 was added at a concentration of 2% as 5i02, and A-12(SO4)3 was added at a concentration of 2% as Am.
% - Add. By reacting in this state, the surface of the phosphor is coated with 0.2 wt% of Aj12S i Os, which causes the blue inorganic pigment to adhere.

A glass sample piece of the obtained mixed phosphor was prepared in the same manner as in Example 1, and the color tone was measured.

The y value and the y value, which are the chromaticity coordinates of the mixed phosphor obtained in Example 2, are x = 0. 346, y=0°452.

Also, the difference between the center and corner in the color shift test using this mixed phosphor is Δx=2/1000, Δy=2
/1000, which was extremely low.

The conventional mixed phosphor manufactured under the same conditions as in Example 2 except that the surface of the blue-emitting phosphor was not coated with a blue inorganic pigment had a color shift between the center and corner of the bulb of Δx=9/ 1000, Δy=16/1000,
The mixed phosphor of the present invention has extremely reduced color shift compared to conventional phosphors.

FIG. 2 shows the difference in the chromaticity diagram between the phosphor obtained in Example 2 of the present invention and a conventional phosphor whose surface is not coated with a blue inorganic pigment. As is clear from this figure, the blue inorganic pigmented mixed phosphor of the present invention effectively suppresses the color shift of the yellow phosphor.

(Example 3) The following materials are used to prototype a mixed phosphor.

Blue phosphor ZnS/Ag, A9 100g cobalt aluminate 1. 25g pure water
0.75 magazine green phosphor Zn25 io4/Mn-As 220g amber phosphor Cd5cQ (Pod) 3/Mn 680
g. Mix the prepared blue phosphor ZnS/Ag-An with pure water. Cobalt aluminate is then added to the blue phosphor to coat it with a blue inorganic pigment.

Mg5iOs is used as an adhesive to attach the inorganic pigment to the surface of the blue-emitting phosphor.

This MgSiO3 combines K2SiO3 and Mg5On,
The blue-emitting phosphor and cobalt aluminate are mixed in pure water and reacted to coat the surface of the phosphor.

K2SiO3 is added in an amount such that the concentration as SiO2 is 2%, and MgSOa is added in an amount such that the concentration as Mg is 2%. By reacting in this state, the surface of the phosphor is coated with 0.3 wt % Zn5iOa, which causes the blue inorganic pigment to adhere.

After drying the obtained phosphor, this blue-emitting phosphor is
A green phosphor (Zn2SiO4/Mn-As) and an amber phosphor [Cd5(,l(POa)a/Mn]) are mixed to obtain a blue, green, and amber mixed phosphor.

Using the obtained mixed phosphor, a glass sample piece was made in the same manner as in Example 1, and the color tone was measured.

The chromaticity coordinate of a mixed phosphor containing three color phosphors is x
=0.389, y=Q, 407.

Also, the difference between the center and corner in the color shift test using this mixed phosphor is Δx=2/1000, Δy=2
/1000, which was extremely small.

The conventional mixed phosphor manufactured under the same conditions as Actual Example 3 except that the surface of the blue-emitting phosphor was not coated with a blue inorganic pigment had a color shift between the center and corner of the bulb of Δx== 9/1000, Δy=16/1000, and the mixed phosphor of the present invention had extremely reduced color shift compared to the conventional phosphor.

(Example 4) The following materials are used as prototype materials for the mixed phosphor.

Blue phosphor (ZnφCd) S/Ag, CfL 110g Ultramarine 2.5g Cobalt aluminate 2.5g Pure water
0.75cL green phosphor Zn2SiO4・Mn-As 240g red phosphor (Zn-Ca)3 (POa) 2/Mn 650g
Mix blue phosphor, ultramarine, and cobalt aluminate with pure water.

Zn5iOs is used as an adhesive for bonding the blue inorganic pigment to the blue-emitting phosphor.

Zn5iO3 is acrylic emulsion and 2Slo3
and Zn5Oa are mixed with pure water in which the blue-emitting phosphor, cobalt aluminate, and ultramarine are mixed, and reacted to coat the surface of the phosphor.

Acrylic emulsion added 0.03wt%, K2S
1Os is added in an amount that gives a concentration of 2% as SiO2, and Zn5Oa is added in an amount that gives a concentration of 2% as Zn. By reacting in this state, 0.1 wt.
% Zn5iO3 coats the surface, which deposits the blue inorganic pigment.

Then it is separated and dried to obtain a phosphor. The obtained phosphor is mixed with green and red phosphors to obtain blue, green, and premixed phosphors.

Using this mixed phosphor, a glass sample piece was made in the same manner as in Example 1, and the color tone was measured.

The chromaticity coordinates of the mixed phosphor are x=0.344, y=0.3
It was 73.

Furthermore, when using the above mixed phosphor, the difference between the center and the corner according to the color shift test is △x=2/1000, Δy
= 3/1000, which was extremely low.

The conventional mixed phosphor manufactured under the same conditions as Example 4 except that the surface of the blue-emitting phosphor was not coated with a blue inorganic pigment had a color shift between the center and corner of the bulb of Δx=6/ 1000, Δy=8/1000, and the mixed phosphor of the present invention had extremely reduced color shift compared to the conventional phosphor.

(Example 5) The following materials are used as prototype materials for the mixed phosphor.

Blue phosphor ZnS/Ag-(,9120g cobalt aluminate 4g pure water
0.6 magazine green phosphor 1nBOa/Tb
480g orange phosphor 1nBOa/Eu
400g Cobalt aluminate was coated on the surface of the blue phosphor in the same manner as in Example 1. Green and orange phosphors were mixed with the obtained phosphor to obtain a blue, green, and orange mixed phosphor.

Using the obtained mixed phosphor, a glass sample piece was made in the same manner as in Example 1, and the color tone was measured.

The chromaticity coordinates of this mixed phosphor are x=0.344, V=o
-373. Also, the difference between the center and corner of this mixed phosphor is ΔX=3/1000, Δy=4/10
It was as low as 00.

The conventional mixed phosphor manufactured under the same conditions as in Example 5 except that the surface of the blue-emitting phosphor was not coated with a blue inorganic pigment had a color shift of Δ! between the center and corner of the bulb. =9/1000, Δy=16/1000,
The mixed phosphor of the present invention has extremely reduced color shift compared to conventional phosphors.

[Brief explanation of the drawing]

FIG. 1 is a graph showing the color shift of the mixed phosphor obtained in Example 1, and FIG. 2 is a graph showing the color shift of the mixed phosphor obtained in Example 2.

Claims (2)

[Claims] (1) A mixture of multiple types of phosphors that emit light in different colors, and a blue-emitting phosphor as at least one component;
In the mixed phosphor containing, as at least one other component, a phosphor that emits visible light when excited by light in the ultraviolet region, the blue-emitting phosphor is coated with a blue inorganic pigment, and the blue inorganic pigment is coated with a blue inorganic pigment. A mixed phosphor whose adhesion amount is 0.01 to 10% by weight based on the blue-emitting phosphor. (2) The mixed phosphor according to claim 1, wherein the blue inorganic pigment is cobalt aluminate.