KR100467670B1 - Green phosphor - Google Patents

Abstract

The present invention provides a green phosphor to which particulate green pigments are attached. The green phosphor according to the present invention not only significantly improves color, reflectance and color coordinate characteristics in the green and blue regions by surface treatment with fine green pigments, but also suppresses deterioration characteristics.

Description

Green phosphor

The present invention relates to a green phosphor, and more particularly, to a green phosphor having a fine size attached to improve body color and reduce external light reflection, thereby improving contrast and preventing deterioration.

Any material can be heated to a sufficiently high temperature to produce visible light by so-called temperature radiation. Most of the light sources or light emitters found in everyday life are high temperature materials. However, some light sources such as neon signs and fluorescent lamps emit light with high efficiency despite the fact that the temperature of the light source is near room temperature.

Thus, the luminescence phenomenon which arises from causes other than temperature radiation is called fluorescence. In order to cause fluorescence, it is necessary to supply energy to the material in any form, which is called stimulation.

The luminescence of the crystalline material may be emitted only during the stimulation and the light emission does not disappear as time passes after the stimulation. The material having such a characteristic is generally called a phosphor.

Phosphors as described above are used for light sources such as fluorescent lamps, fluorescent mercury lamps, and radiation lamps, for display such as cathode ray tubes, electroluminescent devices, electron microscopes, etc., for detecting X-ray sensitizers, scintillaters, and the like. Used.

Hereinafter, the cathode ray tube employing the fluorescent film made of the above-described phosphor will be described.

In general, the cathode ray tube 11 is a transparent window as shown in FIG. 1, a panel 12 having a screen surface 12a for reproducing an image upon reproduction of a screen, and a fluorescent film having a predetermined pattern formed on an inner surface of the screen surface. 13, a shadow mask frame assembly 15 installed inside the panel 12, and a funnel 16 sealed to the panel 12 to form an outer container of a cathode ray tube and having an electron gun 14 installed at a neck portion thereof. ) And a deflection yoke 17 provided in the cone portion 16a of this funnel.

In the cathode ray tube configured as described above, the electron beam emitted from the electron gun 14 is selectively deflected according to the dice by the deflection yoke 17 to be scanned by the fluorescent film 13 to excite each phosphor to form an image. .

As a method for preventing a decrease in reflectance of the fluorescent film 13 itself formed on the panel 12 and improving contrast, a method of coating a pigment on the surface of the phosphor as shown in FIG. 2 is commonly used.

Since the green phosphor of the phosphor component is light green itself, it is common to attach colloidal silica to the surface of the phosphor instead of the pigment. Here, the colloidal silicic acid serves to disperse all light reaching the phosphor.

However, the colloidal silicate-attached green phosphor is excellent in dispersing light incident on the phosphor, but has a problem in that contrast is reduced by external light reflection and the phosphor is not prevented from deteriorating.

In order to solve the above problems, the present inventors have completed the present invention regarding a green phosphor having fine green pigment attached to a surface having a property of blocking ultraviolet rays in a short wavelength region and preventing deterioration of the phosphor.

SUMMARY OF THE INVENTION The present invention has been made in an effort to provide a green phosphor in which a green pigment having a fine size is attached to improve body color and reduce external light reflection to improve contrast and prevent degradation.

The technical problem to be achieved by the present invention is to provide a method for producing the phosphor.

In order to achieve the first object, the present invention provides a green phosphor having a fine green pigment attached to its surface.

The second object of the present invention is to (a) mixing the green phosphor, the solvent and the first binder is attached to the fine green pigment on the surface; (b) mixing the second binder, the pigment particles and the solvent to prepare a pigment milling liquid; (c) adding and mixing the pigment milling liquid prepared in step (b) to the resultant obtained in step (a); (d) adding an acid solution to the resultant to adjust the pH of the mixture; (e) adding or hardening a curing agent to the pH adjusted mixture to obtain a precipitate; And (f) filtrating and drying the obtained precipitate.

The present invention is to improve the color by attaching the green pigment particles having a fine size on the surface of the green phosphor, to reduce the external light reflection to improve the contrast. In this case, it is preferable to use a material that blocks ultraviolet rays in the short wavelength region as a green pigment in terms of preventing degradation of the phosphor.

As a pigment that satisfies the characteristics as described above, there is a cobalt-based composite oxide.

Specific examples of the Co-based composite oxide include Ti-Ni-Co-Zn-based composite oxide, Co-Cr-Ti-Al-based composite oxide, and Co-Al-Cr-Ti-based composite oxide.

It is preferable that the particle diameter of the said green pigment is 100 nm or less. If the particle diameter of the pigment is greater than 100 nm, the dispersibility of the pigment to the surface of the phosphor is poor, and since the luminance is lowered since it shields the visible light emitted from the electron beam and the phosphor, it is not preferable.

The content of the green pigment is 0.05 to 1.0% by weight based on the phosphor, preferably 0.2 to 0.4% by weight. If the content of the green pigment is less than 0.05% by weight, the body color improvement of the phosphor is insufficient, and if the content of the green pigment exceeds 1.0% by weight, the luminance of the phosphor is not preferable.

Hereinafter, the present invention will be described in detail with reference to Examples, but the present invention is not limited only to the following Examples.

<Example 1>

100 g of phosphor (ZnS: Cu, Al), 200 g of pure water, and 0.2 g of gelatin were mixed to adsorb gelatin on the surface of the phosphor.

 Subsequently, 0.2 g of Dainichi Seika 3320, a Ti-Ni-Co-Zn-based composite oxide having a particle diameter of about 20 nm, and 0.2 g of gum arabic were mixed to prepare a pigment milling liquid. After the obtained pigment milling liquid was added to the phosphor, the pH of the mixture was adjusted to about 3 to 4 using acetic acid.

The pH-adjusted result was then freeze-cured to about 5 ° C. next,

The supernatant of the resultant was discarded and the residue was filtered and dried at 100 ° C.

The resultant product was used to obtain a micronized phosphor using a 400 mesh sieve.

<Example 2>

The same procedure as in Example 1 was conducted except that Co-Cr-Ti-Al composite oxide (Dainichi Seika 3330) was used instead of the Ti-Ni-Co-Zn composite oxide.

<Example 3>

 The same procedure as in Example 1 was conducted except that Co-Al-Cr-Ti composite oxide (Dainichi Seika 3340) was used instead of the Ti-Ni-Co-Zn composite oxide.

<Example 4>

 The same procedure as in Example 1 was conducted except that Asahi Sangyo 2040, a Co-Zn-Ni-Ti-based composite oxide, was used instead of the Ti-Ni-Co-Zn-based composite oxide.

Example 5

 The same procedure as in Example 1 was carried out except that Cho Industry 1250, a Co-Cr-Al-Zn composite oxide, was used instead of the Ti-Ni-Co-Zn composite oxide.

<Example 6>

 The same procedure as in Example 1 was carried out except that Cho Industry 2500, a Co-Cr-Zn-Ti composite oxide, was used instead of the Ti-Ni-Co-Zn composite oxide.

Comparative Example 1

Phosphor without any surface treatment was prepared according to a conventional method.

Comparative Example 2

100 g of phosphors (ZnS: Cu, Al) were dispersed in 200 g of pure water, and then colloidal silicic acid was added thereto.

ZnSO ₄ solution was added to the mixture of the phosphor dispersion and the colloidal silicic acid and mixed, and then the pH of the reaction mixture was adjusted to about 7 by adding ammonia water.

The supernatant of the reactant was removed, and then filtered and dried at 100 ° C., to obtain a micronized phosphor using a 400 mesh sieve.

After irradiating ultraviolet rays in a wavelength of 365 nm to the phosphors prepared according to Examples 1-6 and Comparative Examples 1-2, deterioration characteristics over time were measured.

As a result, the phosphor according to Comparative Example 1 deteriorated within 5 seconds, and the phosphor according to Comparative Example 2 deteriorated within 10 seconds, whereas the phosphor according to Examples 1-6 deteriorated even after 30 seconds or more. Not observed. In the case of Comparative Example 2 surface-treated with colloidal silicic acid, colloidal silicic acid scatters visible light of all wavelengths and does not play a role of preventing the deterioration of the phosphor. It became.

On the other hand, reflectance and color coordinates of the phosphors prepared according to Examples 1-6 and Comparative Examples 1-2 were measured and compared.

As a result, in the phosphors according to Examples 1-6, the difference in reflectance at the green and blue wavelengths was 15% or more, which was significantly improved than the reflectance of 5% of the phosphors according to Comparative Examples 1-2.

In the color coordinate characteristic, in the case of Example 1-6, the color coordinate X is lowered from the minimum 1.4% to the maximum 4.8%, and the Y increases from the minimum 0.57% to the maximum 1.4% to darken the color dark green as a whole. lost.

As described above, the phosphors according to Examples 1-6 were Ti-Ni-Co-Zn-based, Co-Cr-Ti-Al-based, Co-Al-Cr-Ti-based, Co-Zn-Ni-Ti-based Surface treatment with, Co-Cr-Al-Zn-based or Co-Cr-Zn-Ti-based composite oxides significantly improved color, color coordinates, reflectance and deterioration characteristics.

According to the present invention, the following effects can be obtained.

First, the color of the phosphor is improved by pigmentation of the surface of the green phosphor.

Second, the reflectance characteristics in the green and blue regions are significantly improved.

Third, deterioration is suppressed.

Fourth, the color coordinate characteristic is improved.

1 is a view showing the structure of a typical cathode ray tube,

2 is a view schematically showing a general green phosphor,

3 is a view schematically showing a green phosphor according to the present invention.

<Explanation of symbols for the main parts of the drawings>

11 ... cathode ray tube 12 ... panel

12a ... screen 13 ... fluorescent film

14 ... EMG 15 ... Shadowmask Frame Assembly

16 ... Funnel 16a ... Funnel Cornu

17 ... deflection yoke 20, 30 ... green phosphor

31 ... Green Pigment

Claims (6)

A green phosphor having a green pigment, which is a cobalt-based composite oxide selected from the group consisting of a Co-Cr-Al-Zn-based composite oxide and a Co-Cr-Zn-Ti-based composite oxide, adhered to a surface thereof. The green phosphor according to claim 1, wherein the content of the green pigment is 0.05 to 1.0 wt% based on the phosphor. The green phosphor according to claim 1, wherein the green pigment has a particle size of 100 nm or less. (a) mixing the green phosphor, the solvent and the first binder; (b) a pigment obtained by mixing a fine green pigment particle and a solvent which is a cobalt-based composite oxide selected from the group consisting of a second binder, a Co-Cr-Al-Zn-based composite oxide and a Co-Cr-Zn-Ti-based composite oxide Preparing a milling liquid; (c) adding and mixing the pigment milling liquid prepared in step (b) to the resultant obtained in step (a); (d) adding an acid solution to the resultant to adjust the pH of the mixture; (e) adding or hardening a curing agent to the pH adjusted mixture to obtain a precipitate; And (f) filtering the obtained precipitate and drying the method of producing a green phosphor. The method of claim 4, wherein the content of the green pigment is 0.05 to 1.0 wt% based on the phosphor. The method for producing a green phosphor according to claim 4, wherein a particle diameter of the green pigment is 100 nm or less.

Images