JP2010077242A - Fluorescent substance paste and plasma display panel - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fluorescent substance paste enabling the precise removal of a medium without accompanying characteristic deterioration of fluorescent particles by firing when forming a fluorescent substance layer at the production of PDP (plasma display panel), and to provide the PDP enabling good image display by using the fluorescent substance paste. <P>SOLUTION: The fluorescent substance paste contains at least the fluorescent substance particles, an organic binder resin and an organic solvent, and the organic binder resin is represented by chemical formula (1) (wherein, n<SB>1</SB>and n<SB>2</SB>are each an integer of 1-10; and n<SB>3</SB>is an integer of ≥1). The PDP is obtained by using the fluorescent substance paste. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a phosphor paste for a plasma display panel and a plasma display panel using the phosphor paste (hereinafter also referred to as PDP), and particularly relates to an organic binder resin contained as a component for constituting the phosphor paste. .

  In recent years, among color display devices used for image display such as computers and televisions, PDPs have attracted attention as color display devices that can be large, thin, and lightweight.

  The PDP performs full color display by additively mixing so-called three primary colors (red, green, and blue). In order to perform this full-color display, the PDP is provided with a phosphor layer that emits each of the three primary colors red (R), green (G), and blue (B), and the phosphor constituting the phosphor layer. The particles are excited by ultraviolet rays generated in the discharge cell of the PDP to generate visible light of each color.

Since the phosphor layer is formed by applying phosphor particles to a substrate, various inorganic materials and an organic binder resin are mixed to form a paste, which is applied by screen printing or a method of discharging from a nozzle (patent) Reference 1).
JP-A-11-96911

  By the way, as the organic binder resin, cellulose ether binder resins such as methyl cellulose, ethyl cellulose, and hydroxypropyl methyl cellulose are widely used. In order to finally emit light as the phosphor layer, it is necessary to burn the organic binder by firing. However, if there is a trace of organic matter at this time, the emission of light will be hindered. It is important to ensure that the organic matter is burned off at a firing temperature that does not degrade the light emission characteristics of the body particles.

  The present invention has been made in view of such a current situation, and a phosphor paste that can be reliably removed without deteriorating the characteristics of phosphor particles due to firing when forming a phosphor layer during PDP production. An object of the present invention is to provide a PDP capable of providing a good image display by using the phosphor paste.

  In order to achieve the above object, the present invention includes at least phosphor particles, an organic binder resin, and an organic solvent, and the organic binder resin is represented by the following chemical formula (1), and a PDP using the phosphor paste It is.

(However, n ₁ and n ₂ in the formula are integers of 1 to 10, and n ₃ is an integer of 1 or more.)

  According to the present invention, it is possible to provide a phosphor paste that can be surely removed without causing deterioration of the characteristics of phosphor particles due to firing at the time of forming a phosphor layer during PDP production, and the phosphor. By using the paste, a PDP capable of displaying a good image can be provided.

  Hereinafter, although one embodiment of the present invention is described, the embodiment of the present invention is not limited to this.

(General structure and manufacturing method of PDP)
FIG. 1 is a cross-sectional view showing a schematic configuration of a discharge cell in a counter AC discharge type PDP according to an embodiment of the present invention. Although only one discharge cell is shown in FIG. 1, a PDP is configured by arranging a large number of discharge cells that emit red, green, and blue colors.

  The PDP discharge cell 1 includes a front panel 2 in which a discharge electrode (display electrode) 12, a dielectric glass layer 13 and a MgO protective layer 14 are arranged on a front glass substrate 11, and an address electrode 16 on a rear glass substrate 15. A discharge gas is enclosed in a discharge space 20 formed between the rear panel 3 on which the dielectric glass layer 17, the partition wall 18, and the symmetrical phosphor layer 19 are arranged. Made as shown.

(Preparation of front panel)
The front panel 2 has a discharge electrode (display electrode) 12 formed on a front glass substrate 11, covered with a lead-based dielectric glass layer 13, and an MgO protective layer 14 on the surface of the dielectric glass layer 13. It is produced by forming.

  In the present embodiment, the discharge electrode (display electrode) 12 is a silver electrode, and after the silver electrode ink containing the ultraviolet photosensitive resin is uniformly applied on the front glass substrate 11 by the screen printing method and dried, It is formed by patterning by exposure and development and baking. The dielectric glass layer 13 is formed by screen printing and baking. The MgO protective layer 14 is made of magnesium oxide [MgO] and is formed by a sputtering method.

(Production of back panel)
In the rear panel 3, an address electrode 16 is formed on a rear glass substrate 15, a dielectric glass layer 17 is formed thereon, and a partition 18 made of glass that divides each discharge chamber into a stripe shape is further formed thereon. In each space sandwiched between the partition walls 18, phosphor layers that emit red light, phosphor particles that emit green light, and phosphor particles that emit blue light, respectively. 19 is formed.

  In the above configuration, the address electrode 16 is a silver electrode, and silver electrode ink containing an ultraviolet photosensitive resin is uniformly applied on the back glass substrate 15 by the screen printing method and dried. Then, it is formed by patterning by exposure and development and baking.

  The dielectric glass layer 17 is formed by slit die coating or screen printing.

  The partition wall 18 may be formed by repeatedly printing several times by a screen printing method, or a so-called sand blasting method or a photolithography method may be used.

As a method of forming the phosphor layer 19 with each of the red, green, and blue phosphor particles in each space sandwiched by the partition walls 18, the phosphor particles are made into a paste, and this phosphor paste is used to perform screen printing. Examples thereof include a method of coating by an inkjet method and a method of discharging from a nozzle or a needle. As the phosphor particles constituting the phosphor layers of the respective colors, phosphor particles used in general PDP can be used. Here, an example using a phosphor having a composition represented by the following chemical formula is used. Indicates.
[Red phosphor]: (Y _X Gd _1-X ) BO ₃ : Eu ³⁺ or YBO ₃ : Eu ³⁺
[Green phosphor]: BaAl ₁₂ O ₁₉ : Mn, or Zn ₂ SiO ₄ : Mn, or YBO ₃ : Tb
[Blue phosphor]: BaMgAl ₁₀ O ₁₇ : Eu ²⁺
(Production of PDP by panel bonding)
Next, the front panel 2 and the back panel 3 manufactured as described above are bonded together using sealing glass, and the inside of the discharge space 20 partitioned by the partition wall 18 is subjected to high vacuum (8 × 10 ⁻⁷ Torr). Then, a PDP is produced by sealing a discharge gas having a predetermined composition at a predetermined pressure. The composition of the discharge gas to be sealed is the Ne-Xe system conventionally used, but the Xe content is set to 5% by volume or more, and the sealing pressure is set to a range of 400 to 800 Torr. Thus, the PDP is completed.

  Next, the phosphor paste in the above description will be described in detail below.

(Preparation of phosphor paste)
As the phosphor paste, an organic binder resin represented by the following chemical formula (1) was used.

(However, n ₁ and n ₂ in the formula are integers of 1 to 10, and n ₃ is an integer of 1 or more.)
In the above, it is preferable that the organic binder resin is represented by the following chemical formula (2) where n ₁ = n ₂ = 3.

(However, n ₃ is an integer of 1 or more.)
The phosphor paste according to one embodiment of the present invention has a weight average molecular weight in the range of 10,000 to 500,000 and a number average molecular weight of 5,000 to 100,000 as an organic binder resin that is a constituent thereof. A range is preferred. Among them, a binder resin having a weight average molecular weight of 50,000 to 60,000 and a number average molecular weight of 9,000 to 11,000 is particularly preferable because it has good viscosity characteristics and is easy to handle.

In addition, the phosphor paste according to an embodiment of the present invention is a phosphor material particle that can efficiently emit light under excitation with vacuum ultraviolet rays having a wavelength of 200 nm or less, for example, 147 nm, as the constituent phosphor particles. It is preferable. Among them, [(Y, Gd, Eu) BO ₃ ], [(Zn, Mn) ₂ SiO ₄ ], and [(Ba, Eu) MgAl ₁₀ O ₁₇ ] are particularly preferable because both the luminous efficiency and the hue are good. The phosphor paste only needs to contain at least one selected from these, and is not limited to the above three types.

  Furthermore, the phosphor paste according to one embodiment of the present invention is not particularly limited as long as it has an organic solvent as a constituent component and has a boiling point of 100 ° C. to 300 ° C. and does not separate from the binder and the phosphor particle component. However, alcohol-based, ether-based and ester-based ones are preferable. For example, terpineol (boiling point 217 ° C.), benzyl alcohol (boiling point 205 ° C.), N-methylpyrrolidone (boiling point 202 ° C.), diethylene glycol monobutyl ether (boiling point 231 ° C.), triethylene glycol monomethyl ether (boiling point 245 ° C.), triethylene glycol Dimethyl ether (boiling point 216 ° C.) or the like is preferable because of its excellent workability.

  Here, the composition of the phosphor paste according to the embodiment of the present invention is listed below for each color.

Composition composition of red phosphor paste:
Organic binder resin represented by chemical formula (Chemical Formula 2) 10wt%
Benzyl alcohol 42wt%
Red phosphor powder [(Y, Gd, Eu) BO ₃ ] 48 wt%
Composition composition of green phosphor paste:
Organic binder resin represented by chemical formula (Chemical Formula 2) 10wt%
Benzyl alcohol 44wt%
Green phosphor powder [(Zn, Mn) ₂ SiO ₄ ] 46 wt%
Composition composition of blue phosphor paste:
Organic binder resin represented by chemical formula (Chemical Formula 2) 10wt%
Benzyl alcohol 45wt%
Blue phosphor powder [(Ba, Eu) MgAl ₁₀ O ₁₇ ] 45 wt%
Moreover, the paste of the following composition structure using an ethyl cellulose binder was produced as a fluorescent substance paste for a comparison.

Composition of the red phosphor paste for comparison:
Ethylcellulose (15cPs) 10wt%
Benzyl alcohol 42wt%
Red phosphor powder [(Y, Gd, Eu) BO ₃ ] 48 wt%
Composition of comparative green phosphor paste:
Ethylcellulose (15cPs) 10wt%
Benzyl alcohol 44wt%
Green phosphor powder [(Zn, Mn) ₂ SiO ₄ ] 46 wt%
Composition of blue phosphor paste for comparison:
Ethylcellulose (15cPs) 10wt%
Benzyl alcohol 45wt%
Blue phosphor powder [(Ba, Eu) MgAl ₁₀ O ₁₇ ] 45 wt%
(Measurement of viscosity of each paste)
About each phosphor paste produced above, the viscosity at “shear rate 1 s ⁻¹ at 25 ° C.” was measured. The results are shown in FIG.

  In each phosphor paste, it can be seen that the phosphor paste of the present invention and the phosphor paste of the comparative product have substantially the same viscosity characteristics.

  Therefore, when the phosphor layer is formed, it is considered that the results of density, shape, etc. when coating with each of these phosphor pastes are equivalent, and the brightness evaluation on the coating described below is effective. It can be said that.

(Measurement of brightness of each paste)
Each phosphor paste was coated on a glass plate so that the film thickness was 20 μm to 30 μm (2.5 cm × 2.5 cm), dried at 110 ° C. for 30 minutes, fired according to the following profile, and fluorescent. A body layer was prepared.

Firing profile:
Room temperature → 420 ° C. 20 minutes 420 ° C. → 420 ° C. 20 minutes 420 ° C. → 520 ° C. 10 minutes 520 ° C. → 520 ° C. 10 minutes 520 ° C. → room temperature 30 minutes Vacuum of 147 nm on the phosphor layer produced by baking above The luminance was measured under ultraviolet excitation. The results are shown in FIG.

  It can be seen that the phosphor layer produced using the phosphor paste according to the embodiment of the present invention has higher luminance than the phosphor paste using the ethyl cellulose binder.

  That is, the present invention provides a phosphor paste in which organic substances are surely burned off at a firing temperature that does not deteriorate the light emission characteristics of the phosphor particles when the solvent is removed in the firing step. Since the characteristics deteriorate due to the traces of organic matter, it is essential that the removal of the solvent and firing be performed without leaving traces of the organic matter. According to the phosphor paste according to one embodiment of the present invention described above, Since the organic binder resin represented by the chemical formula (1) or (2) is used, it is carbonized after firing as compared with the cellulose ether binder and the thermally decomposable acrylic binder that have been conventionally used as the organic binder. Residues are difficult to remain, and heat generated during combustion is slow and does not place a heavy load on the phosphor particles. Provided is a PDP phosphor paste that can be surely removed without deteriorating characteristics, and a PDP capable of displaying a good image by using this PDP phosphor paste. It becomes possible.

  As described above, the present invention is useful for providing a large-screen, high-definition PDP.

Sectional drawing which shows schematic structure of the discharge cell in counter alternating current discharge type PDP by one embodiment of this invention The figure which shows the result of having measured the viscosity of the fluorescent substance paste in 25 degreeC and shear rate 1s ^-1 The figure which shows the result of having measured the brightness | luminance under the vacuum ultraviolet-ray excitation of 147 nm with respect to a fluorescent substance layer

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Discharge cell 2 Front panel 3 Rear panel 11 Front glass substrate (front cover plate)
12 Display electrode 13 Dielectric glass layer 14 Dielectric protective layer (MgO)
15 Back glass substrate (back plate)
16 Address electrode 17 Dielectric glass layer 18 Partition wall 19 Phosphor layer 20 Discharge space

Claims (5)

A phosphor paste comprising at least phosphor particles, an organic binder resin, and an organic solvent, wherein the organic binder resin is represented by the following chemical formula (1).

(However, n ₁ and n ₂ in the formula are integers of 1 to 10, and n ₃ is an integer of 1 or more.) The phosphor paste according to claim 1, wherein the apparent viscosity when the shear rate is 1 [s ^-1 ] at 25 ° C, that is, the viscosity coefficient is in the range of 5 to 500 [Pa · s]. The phosphor particles include at least one selected from [(Y, Gd, Eu) BO ₃ ], [(Zn, Mn) ₂ SiO ₄ ], and [(Ba, Eu) MgAl ₁₀ O ₁₇ ]. Item 6. The phosphor paste according to Item 1. The phosphor paste according to claim 1, wherein the boiling point of the organic solvent is in the range of 100 to 300 ° C. A plasma display panel using the phosphor paste according to claim 1.

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