KR20010093345A - Red-emitting phosphors for plasma display panel - Google Patents

Abstract

PURPOSE: A red light emitting fluorescent substance for a plasma display panel is provided, which comprises vanadium oxide, to reduce the afterglow time without the decrease of brightness, thereby improving the image quality. CONSTITUTION: The red light emitting fluorescent substance is represented by (Y, Gd)(BO3)1-x (VO4):Eu, wherein x is 0.0001 to 0.10. The red light emitting fluorescent substance is prepared by the know methods such as the solid chemical process, the coprecipitation and the sol-gel method. Preferably the red light emitting fluorescent substance is prepared by weighing the complex oxide of Y, Gd and Eu ((YGdEu)2O3), B2O3 and V2O5, and mixing them; sintering the mixture under the air, nitrogen or reductive atmosphere; and washing, grinding, drying and sieving it.

Description

Red-emitting phosphors for plasma display panel

The present invention relates to a phosphor, and more particularly, to a red light-emitting phosphor for a plasma display panel (PDP) having excellent brightness and a short afterglow time.

Phosphor refers to a material having a property of emitting light due to energy stimulation other than temperature radiation, and most of the phosphors that are practically used today are artificially synthesized by industrial technology rather than natural minerals.

Phosphors are generally used for light sources such as fluorescent lamps, fluorescent mercury lamps, radiation lamps and the like; For display elements such as cathode ray tubes, electroluminescent elements, plasma display panels and the like; And X-ray sensitizers, scintillaters, etc., and other detection devices.

Phosphors should be chosen to have the characteristics of excitation in the wavelength range of the light source to which the device employing them is exposed. And other physical properties should be provided.

In particular, the phosphors used in the plasma display panel are excited by the light in the vacuum ultraviolet region generated during the gas discharge in a mixed gas such as neon and xenon, and then, blue, respectively, by the visible light that emits according to the respective phosphor composition. The color image is driven by emitting green and red visible light.

Therefore, in order to develop a phosphor for a plasma display panel having high brightness and long life, external ambient conditions such as the type of gas used at the time of discharge, pressure, and driving voltage should be considered.

From the foregoing, one of the suitable red light emitting phosphors for PDP is (Y, Gd) BO ₃ : Eu. This phosphor has the characteristics of high brightness and long life, as well as satisfactory color coordinate characteristics, and has the advantage that the shape and particle size are suitable for PDP.

However, this phosphor has an afterglow time that varies depending on the symmetry around the Eu ions and is spin-forbidden so that afterglow time is 7.2ms or more, which is longer than 5ms that is generally allowed. There is a problem that the occurrence is serious.

Various improved phosphors have been proposed to overcome the problems of the conventional red light-emitting phosphors, but these phosphors are not suitable for practical use because they have a problem that the luminance decreases in proportion to the reduction of afterglow time.

The present invention seeks to overcome these prior art problems.

The technical problem to be achieved by the present invention is to provide a red light-emitting phosphor for a plasma display panel suitable for use in a PDP by reducing the afterglow time without lowering the luminance.

Technical problem of the present invention can be achieved by a red light emitting phosphor for a plasma display panel represented by the following formula.

(Y, Gd) (BO ₃ ) _1-x (VO ₄ ) _x : Eu

Wherein x is from 0.0001 to 0.10.

In the red light-emitting phosphor according to the present invention, when vanadium oxide is added only to the extent that the x value can be maintained in the above range, the resulting phosphor forms a crystal structure of a complete solid solution and reduces the afterglow time without deteriorating the luminance.

However, if the x value is smaller than the above range, the afterglow time is undesirably exceeding 5 ms, which is a generally required level. On the other hand, if the x value exceeds the above range, the crystal structure is changed into a mixed crystal structure so that the luminous intensity is emitted. It is not desirable because it not only drops a lot but also changes the color coordinate.

Although the mechanism of reducing the afterglow time without affecting the luminance of the red light-emitting phosphor according to the present invention is not known precisely, a predetermined amount of vanadium added to the matrix of the conventional red light-emitting phosphor (Y, Gd) BO ₃ : Eu It is determined that the oxide (V ₂ O ₅ ) changes the forbidden transition to a fast transition by changing the crystal structure of the red light-emitting phosphor, which shortens the afterglow time.

The red light-emitting phosphor according to the present invention can be prepared by any method known in the art, for example, solid chemical reaction method, coprecipitation method, sol-gel method.

For example, a method of manufacturing a red light-emitting phosphor according to the present invention, iridium, gallium, europium complex oxide ((YGdEu) ₂ O ₃ ), boron oxide (B ₂ O ₃ ) and vanadium oxide (V ₂ O ₅ ) Are weighed a predetermined amount and then mixed.

For example, the mixture is calcined at a predetermined temperature in an air atmosphere, nitrogen or a reducing atmosphere for a predetermined time, and then the calcined phosphor is washed, pulverized, dried and sieve to obtain a desired red light-emitting phosphor.

On the other hand, also in the manufacturing of a fluorescent film using the red light-emitting phosphor obtained in this way, by any existing methods, such as screen printing (photo printing), photolithography (photolithography).

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

Examples 1-4

Raw materials (YGdEu) ₂ O ₃ , B ₂ O ₃ and V ₂ O ₅ were weighed and mixed as shown in Table 1 below, and then calcined at 1200 ° C. for 3 hours under a reducing atmosphere. The calcined mixture was washed, then triturated, dried and sieve to obtain phosphors as shown in Table 1. The afterglow time, relative luminance, and X and Y coordinate values of the obtained phosphors were measured and shown in Table 2 below.

Example number (YGdEu) ₂ O ₃ (g) B ₂ O ₃ (g) V ₂ O ₅ (g) Obtained phosphor One 20 5.49 0.066 (Y, Gd) (BO ₃ ) _0.09 (VO ₄ ) _0.01 : Eu 2 20 5.38 0.198 (Y, Gd) (BO ₃ ) _0.07 (VO ₄ ) _0.03 : Eu 3 20 5.27 0.329 (Y, Gd) (BO ₃ ) _0.05 (VO ₄ ) _0.05 : Eu 4 20 5.16 0.658 (Y, Gd) (BO ₃ ) _0.9 (VO ₄ ) _0.1 : Eu

Example number Afterglow time (seconds) Relative luminance () x coordinate y coordinate One 5.4 101 0.642 0.352 2 3.0 95 0.642 0.353 3 2.6 97 0.642 0.352 4 2.5 87 0.645 0.350

Comparative Examples 1 to 3

Phosphors were obtained in the same manner as in Examples 1 to 4, except that (YGdEu) ₂ O ₃ , B ₂ O _3, and V ₂ O _{5, which} were raw materials, were weighed and used as shown in Table 3 below. The afterglow time, relative luminance, and X and Y coordinate values of the obtained phosphors were measured and shown in Table 4 below.

Comparative example number (YGdEu) ₂ O ₃ (g) B ₂ O ₃ (g) Nb ₂ O ₅ (g) Obtained phosphor One 20 5.55 - (Y, Gd) (BO ₃ ): Eu 2 20 5.52 0.073 (Y, Gd) (BO ₃ ) _0.995 (VO ₄ ) _0.005 : Eu 3 20 4.99 1.317 (Y, Gd) (BO ₃ ) _0.8 (VO ₄ ) _0.2 : Eu

Comparative example number Afterglow time (seconds) Relative luminance () x coordinate y coordinate One 7.2 100 0.642 0.352 2 6.0 101 0.642 0.352 3 1.8 78 0.647 0.348

As can be seen from the results of the above table, in the case of the red light-emitting phosphors (Examples 1 to 4) of the present invention containing a predetermined amount of vanadium oxide, the afterglow time is greatly shortened while maintaining the color coordinates and the luminance characteristics. .

On the other hand, it can be seen that the afterglow time is too long in the case of the conventional red light-emitting phosphor (Comparative Example 1) or the red light-emitting phosphor (Comparative Examples 2 and 3) in which the content of vanadium oxide is out of the range of the present invention.

The red light emitting phosphor for plasma display panel according to the present invention contributes to the improvement in image quality since the afterglow time is greatly shortened without long brightness after the reduction of luminance.

Claims (1)

Red light-emitting phosphor for a plasma display panel represented by the following formula. (Y, Gd) (BO ₃ ) _1-x (VO ₄ ) _x : Eu Wherein x is from 0.0001 to 0.10.