KR100728161B1 - Green phosphor composition for plasma display panel and plasma display panel comprising same - Google Patents

Abstract

The present invention relates to a green phosphor composition for a plasma display panel and a plasma display panel including the same, wherein the green phosphor composition includes a first phosphor having a structure of Formula 1 and a second phosphor of CaSiO ₃ : Eu do:

[Formula 1]

Zn _{2 (1-x)} M _2x SiO ₄ : Mn

(In Formula 1, M is at least one element selected from the group consisting of Ca, Mg, Sr, and Ba, x≤0.1.)

The green phosphor composition of the present invention can improve the afterglow property of the plasma display panel.

Plasma Display Panel, Green Phosphor, Afterglow

Description

Green phosphor composition for plasma display panel and plasma display panel including the same {GREEN PHOSPHOR COMPOSITION FOR PLASMA DISPLAY PANEL AND PLASMA DISPLAY PANEL COMPRISING SAME}

1 is an exploded perspective view showing an example of a plasma display panel of the present invention.

[Industrial use]

The present invention relates to a green phosphor composition for a plasma display panel and a plasma display panel including the same, and more particularly, to a green phosphor composition for a plasma display panel and a plasma display panel including the same that can improve afterglow characteristics.

[Prior art]

The plasma display panel is a display device using a plasma phenomenon, and discharge occurs when at least one potential difference is applied between two spatially separated contacts in a gas atmosphere in a non-vacuum state, which is called a gas discharge phenomenon.

A plasma display element is a flat panel display element which applied such gas discharge phenomenon to image display. A plasma display panel generally used at present is a reflective AC drive plasma display panel, and in the case of a bottom plate structure, a phosphor layer is formed on a partition wall.

In order for the plasma display panel to exhibit a uniform and stable discharge, the surface potential of the phosphor is high, and high temperature gaseous anions must collide with the phosphor layer at high speed. The higher the surface potential of the phosphor, the greater the potential difference between the phosphor and the anion, thereby realizing a plasma discharge exhibiting uniform and stable light emission characteristics. These phosphors are manufactured by mixing solid powder raw materials and firing them at a high temperature. The surface potential of the phosphors may vary depending on the composition and raw material properties of the phosphors thus prepared.

In particular, zinc silicate-based (Zn ₂ SiO ₄ : Mn) green phosphors, which are most widely used as green phosphors for plasma display panels, vary in color purity, luminance, lifetime, and afterglow depending on the amount of Mn as a light emitting material. If the afterglow time is shortened by adjusting the amount of Mn of the phosphor, it is disadvantageous in color purity, luminance and lifetime, and if the afterglow time is long, afterglow is visually observed on the panel.

Zn ₂ SiO ₄ : Mn green phosphor can be prepared by mixing solid raw materials of ZnO, SiO ₂ , MnCO ₃ , where a product with intermediate or non-uniform composition ratio is formed, unlike surface phosphors of red and blue Has a negative charge. This affects the potential of the surface of the phosphor layer in the panel, so that the wall charges are accumulated during the reset discharge of a typical plasma display driving. This results in an increase in the address discharge voltage added for discharge in the next address discharge period. That is, the green phosphor has a lower surface potential than the red and blue phosphors, so that a high discharge start voltage is required. Therefore, studies are being conducted to increase the surface potential of the green phosphor to have a surface potential similar to that of the red and blue phosphors.

The present invention is to solve the above-described problems, to provide a green phosphor composition for a plasma display panel that can improve the afterglow characteristics of the plasma display panel.

Another object of the present invention is to provide a plasma display panel having improved afterglow properties, including the green phosphor composition.

In order to achieve the above object, the present invention provides a green phosphor composition for a plasma display panel comprising a first phosphor having a structure of Formula 1, and a second phosphor of CaSiO ₃ : Eu:

[Formula 1]

Zn _{2 (1-x)} M _2x SiO ₄ : Mn

(In Formula 1, M is at least one element selected from the group consisting of Ca, Mg, Sr, and Ba, x ≤ 0.1.)

According to another embodiment of the present invention, a plasma display panel including a red phosphor layer, a green phosphor layer, and a blue phosphor layer, wherein the green phosphor layer includes the green phosphor composition. .

Hereinafter, the present invention will be described in more detail.

Zn ₂ SiO ₄ : Mn, which is most widely used as a green phosphor for plasma display panels, has the advantage of high luminance and color purity. However, since the afterglow time is very long, it causes a problem in the implementation of the video, and also causes the luminance saturation problem.

On the other hand, the present invention was able to improve the afterglow characteristics of the panel in the plasma display by using a CaSiO ₃ : Eu phosphor having a short afterglow time in the form of small particles.

That is, the green phosphor composition for a plasma display panel according to an embodiment of the present invention comprises a first phosphor having a structure of Formula 1; And a second phosphor of CaSiO ₃ : Eu:

[Formula 1]

Zn _{2 (1-x)} M _2x SiO ₄ : Mn

(In Formula 1, M is at least one element selected from the group consisting of Ca, Mg, Sr, and Ba, x≤0.1.)

In Formula 1, x represents the doping rate of M, preferably x ≦ 0.1, more preferably 0 ≦ x ≦ 0.05, and even more preferably 0.001 ≦ x ≦ 0.05. When the x value exceeds 0.1, there is a possibility that the color purity may be lowered, which is not preferable.

CaSiO ₃ : Eu, which is the second fluorescent material, contains Eu as an activator instead of Mn, and thus has afterglow of 1 ms or less.

The second fluorescent substance may further include one or more doping elements selected from the group consisting of Mg, Sr, and Ba, wherein the doping element is 0.01 to 10 mol%, more preferably 0.1 to 5 in CaSiO ₃ It may be included as mole%. If the content of the doping element is less than 0.01 mol%, the effect of containing the doping element is insignificant, and if it exceeds 10 mol%, there is a possibility that the afterglow time may be long, which is not preferable.

In addition, the first fluorescent material may be included in 50 to 99% by weight, more preferably 80 to 95% by weight relative to the total weight of the green phosphor composition. In addition, the second fluorescent material may be included in 1 to 50% by weight, more preferably 5 to 20% by weight based on the total weight of the green phosphor composition. When the content of the first fluorescent material and the second fluorescent material is in the above range can be obtained an excellent afterglow time improvement effect, if the weight ratio is out of the range and the content of the second fluorescent material is too much there is a possibility that the brightness is lowered Not desirable

The green phosphor composition of the present invention may further include a third fluorescent material for improving color reproduction and lifespan in addition to the first and second fluorescent materials.

Such a third fluorescent substance may include at least one fluorescent substance selected from the group consisting of barium-based fluorescent materials and rare earth-based fluorescent materials, specifically BaAl ₁₂ O ₁₉ : Mn, (BaSrMg) O · aAl It may include one or more selected from the group consisting of ₂ O ₃ : Mn, YBO ₃ : Tb and (Y, Gd) BO ₃ : Tb.

The content of the third fluorescent substance may be appropriately adjusted in consideration of afterglow time improvement and luminance decrease. Specifically, the third fluorescent material may be included in an amount of 50 to 100 parts by weight, and more preferably 60 to 90 parts by weight, based on 100 parts by weight of the green phosphor composition. If it is out of the content range, there is a risk that the color purity decreases and the afterglow time may be long.

The green phosphor composition according to an embodiment of the present invention may further include a binder and a solvent. Examples of the binder and the solvent are as described below, but are not limited thereto.

As the binder, it is preferable to use those which are all removed during firing during the phosphor formation process and do not remain in the finally manufactured plasma display panel. Specifically, a cellulose resin, an acrylic resin or a mixture thereof having a-(CH ₂ -CH ₂ -CH ₂ ) n-chain can be used. As the cellulose resin, for example, methyl cellulose, ethyl cellulose, propyl cellulose, hydroxymethyl cellulose, hydroxyethyl cellulose, hydroxypropyl cellulose, hydroxyethylpropyl cellulose, nitro cellulose or a mixture thereof may be used. have. As said acrylic resin, For example, Polymethyl (meth) acrylate; Polyisopropyl (meth) acrylate; Polyisobutyl (meth) acrylate; Methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, hexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, benzyl (meth) acrylic Rate, dimethylaminoethyl (meth) acrylate, hydroxyethyl (meth) acrylate, hydroxypropyl (meth) acrylate, hydroxybutyl (meth) acrylate, phenoxy 2-hydroxypropyl (meth) acrylate , Glycidyl (meth) acrylate, methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate, hexyl acrylate, 2-ethylhexyl acrylate, benzyl acrylate, dimethylaminoethyl acrylate, hydroxyethyl Such as acrylate, hydroxypropyl acrylate, hydroxybutyl acrylate, phenoxy 2-hydroxypropyl acrylate or glycidyl acrylate Copolymers of acrylic monomers; Or mixtures thereof may be used. In some cases, the phosphor composition may include a small amount of an inorganic binder. The content of the binder resin is preferably used in about 2 to 8% by weight based on the total weight of the green phosphor composition.

As the solvent, for example, alcohols, ethers, esters, or mixtures thereof, which are generally used in phosphor compositions, may be used. More preferably, butyl cellosolve (BC), butyl carbitol acetate (butyl carbitol acetate: BCA), α-terpineol, or mixtures thereof, and the like, and most preferably a mixed solvent of butyl carbitol acetate and terpineol. If the content of the solvent is too high or too low, the flow characteristics of the composition is not appropriate, the process of forming a green phosphor layer may not be easy. In consideration of this point, the content of the solvent may include 25 to 75 wt% based on the total weight of the phosphor composition.

In addition, the green phosphor composition of the present invention may further include other additives to improve the flow characteristics, process characteristics and the like. As the additive, for example, various additives such as a photosensitizer, a dispersant, a silicone-based antifoaming agent, a leveling agent, a plasticizer, an antioxidant, and the like may be used alone or in combination, all of which are all used in the art. Commercially available to those skilled in the art.

The green phosphor composition is prepared by mixing the first fluorescent substance and the second fluorescent substance, and then dispersing the binder resin in a vehicle dissolved in a solvent to form a paste.

The green phosphor composition of the present invention includes a zinc silicate-based first phosphor and a CaSiO ₃ : Eu second phosphor, thereby improving afterglow of the green phosphor in a plasma display panel to 10 ms or less.

According to another embodiment of the present invention, there is provided a plasma display panel including a green phosphor layer formed by applying any one of the green phosphor composition to a discharge cell.

That is, the plasma display panel includes a phosphor layer including a red phosphor layer, a green phosphor layer, and a blue phosphor layer.

The green phosphor layer may include a first phosphor having a structure of Formula 1 below; And a green phosphor composition comprising a second phosphor of CaSiO ₃ : Eu.

[Formula 1]

Zn _{2 (1-x)} M _2x SiO ₄ : Mn

(In Formula 1, M is at least one element selected from the group consisting of Ca, Mg, Sr, and Ba, x≤0.1.)

The first fluorescent material and the second fluorescent material are the same as described above.

Various manufacturing methods and structures of the phosphor layer and other components constituting the plasma display panel are well known, and any of the known ones may be applied to the plasma display panel of the present invention, and thus the detailed description thereof will be omitted.

1 is an exploded perspective view showing an example of a plasma display panel of the present invention. However, the plasma display panel of the present invention is not limited to the structure of FIG. 1.

Referring to the drawings, in the plasma display panel of the present invention, address electrodes 3 are formed in one direction (Y direction in the drawing) on the first substrate 1, and the first electrodes cover the address electrodes 3. The dielectric layer 5 is formed on the front surface of the substrate 1. A partition wall 7 is formed between the address electrodes 3 on the dielectric layer 5, and phosphor layers 9 of red (R), green (G), and blue (B) colors are formed between the partition walls 7. ) Is located. In this case, the green phosphor layer 9 includes any one of the green phosphor compositions of the present invention.

In addition, a pair of transparent electrodes 13a and bus electrodes 13b are disposed on one surface of the second substrate 11 opposite to the first substrate 1 in a direction orthogonal to the address electrode 3 (the X direction in the drawing). The display electrodes 13 may be formed, and the transparent dielectric layer 15 and the passivation layer 17 may be disposed on the entirety of the second substrate 11 while covering the display electrodes 13. Any one of the paired display electrodes 13 is called a sustain electrode (X electrode), and the other is called a scan electrode (Y electrode). As a result, the intersection of the address electrode 3 and the display electrode 13 constitutes a discharge cell.

With this configuration, the address discharge is applied by applying the address voltage Va between the address electrode 3 and any one of the display electrodes 13, and again discharged between the pair of display electrodes (X electrode and Y electrode). When the sustain voltage Vs is applied, vacuum ultraviolet rays generated during sustain discharge excite the phosphor layer 9 to emit visible light through the transparent front substrate 11.

Hereinafter, preferred embodiments of the present invention are described. However, the following examples are only preferred embodiments of the present invention, and the present invention is not limited by the following examples.

(Example 1)

The first phosphor Zn ₂ SiO _4: 95 wt% Mn and the second phosphor CaSiO ₃ : Eu 5 wt% were mixed to obtain a phosphor powder. At this time, the afterglow time of Zn ₂ SiO ₄ : Mn was 12ms.

2000 g of a phosphor paste was prepared by dispersing 40 wt% of the phosphor powder in a vehicle in which 5.7 wt% of ethyl cellulose was dissolved in 54.3 wt% of a 30:70 mixed solvent of butyl carbitol acetate and α-terpineol. Then, the phosphor paste was milled and screen printed between the partition walls shown in FIG. 1 and then fired at 500 ° C. to form a green phosphor layer, thereby manufacturing a plasma display panel.

(Examples 2 to 12 and Comparative Examples 1 and 2)

A plasma display panel was manufactured in the same manner as in Example 1, except that phosphor powders prepared by mixing phosphors in the amounts shown in Table 1 were used. At this time, the afterglow time of Zn ₂ SiO _4: Mn used in Examples 2 to 6 and Comparative Example 1 was 12 ms, and the afterglow time of Zn ₂ SiO _4: Mn used in Examples 7 to 12 and Comparative Example 2 was 9 ms.

Fluorescent material First fluorescent substance (% by weight) Second fluorescent substance (% by weight) Third fluorescent substance (% by weight) Comparative Example 1 Zn ₂ SiO _4: Mn (100) - - Example 1 Zn ₂ SiO _4: Mn (95) CaSiO ₃ : Eu (5) - Example 2 Zn ₂ SiO _4: Mn (90) CaSiO ₃ : Eu (10) - Example 3 Zn ₂ SiO _4: Mn (80) CaSiO ₃ : Eu (20) - Example 4 Zn ₂ SiO _4: Mn (70) CaSiO ₃ : Eu (30) - Example 5 Zn ₂ SiO _4: Mn (60) CaSiO ₃ : Eu (40) - Example 6 Zn ₂ SiO _4: Mn (50) CaSiO ₃ : Eu (50) - Comparative Example 2 Zn ₂ SiO _4: Mn (55) - YBO ₃ : Tb (40) (BaSrMg) OaAl ₂ O ₃ : Mn (5) Example 7 Zn ₂ SiO _4: Mn (52.25) CaSiO ₃ : Eu (2.25) YBO ₃ : Tb (40) (BaSrMg) OaAl ₂ O ₃ : Mn (5) Example 8 Zn ₂ SiO _4: Mn (49.5) CaSiO ₃ : Eu (4.5) YBO ₃ : Tb (40) (BaSrMg) OaAl ₂ O ₃ : Mn (5) Example 9 Zn ₂ SiO _4: Mn (44) CaSiO ₃ : Eu (11) YBO ₃ : Tb (40) (BaSrMg) OaAl ₂ O ₃ : Mn (5) Example 10 Zn ₂ SiO _4: Mn (38.5) CaSiO ₃ : Eu (16.5) YBO ₃ : Tb (40) (BaSrMg) OaAl ₂ O ₃ : Mn (5) Example 11 Zn ₂ SiO _4: Mn (33) CaSiO ₃ : Eu (22) YBO ₃ : Tb (40) (BaSrMg) OaAl ₂ O ₃ : Mn (5) Example 12 Zn ₂ SiO _4: Mn (27.5) CaSiO ₃ : Eu (27.5) YBO ₃ : Tb (40) (BaSrMg) OaAl ₂ O ₃ : Mn (5)

After lighting only the green phosphor layer of the plasma display panel in Examples 1 to 12 and Comparative Examples 1 and 2, the CaSiO ₃ : Eu content was adjusted using a contact luminance meter (CA-100 +, manufactured by Toshiba Chemical Co., Ltd.). Afterglow of green light was measured. The measurement results are shown in Table 2 below.

CaSiO ₃ : Eu content (% by weight) Afterglow time (ms) Comparative Example 1 - > 12 Example 1 5 11.4 Example 2 10 10.7 Example 3 20 9.5 Example 4 30 8.5 Example 5 40 7.1 Example 6 50 6.3 Comparative Example 2 - 10 Example 7 5 9.4 Example 8 10 8.9 Example 9 20 8.0 Example 10 30 6.8 Example 11 40 5.9 Example 12 50 4.9

As shown in Table 2, CaSiO _3: can be confirmed shows excellent afterglow time as compared to Comparative Examples 1 and 2 did not contain Eu: Examples 1 to 12 In, CaSiO ₃ using a mixture of Eu .

The green phosphor composition of the present invention can improve the afterglow property of the plasma display panel.

Claims (10)

A first fluorescent substance having a structure represented by Formula 1 below; And CaSiO ₃ : Eu 2nd fluorescent material Green phosphor composition for a plasma display panel comprising: [Formula 1] Zn _{2 (1-x)} M _2x SiO ₄ : Mn (In Formula 1, M is at least one element selected from the group consisting of Ca, Mg, Sr, and Ba, x ≤ 0.1.) The method of claim 1, The second phosphor is Mg, Sr, and green phosphor composition for a plasma display panel further comprises one or more doping elements selected from the group consisting of Ba. The method of claim 2, Wherein the doping element is doped with CaSiO ₃ of the second fluorescent material at 0.01 to 10 mol%. The method of claim 1, The first phosphor is 50 to 99% by weight relative to the total weight of the green phosphor composition green phosphor composition for a plasma display panel. The method of claim 1, Wherein the second phosphor is 1 to 50% by weight based on the total weight of the green phosphor composition green phosphor composition for a plasma display panel. The method of claim 1, The green phosphor composition further comprises one or more phosphors selected from the group consisting of barium-based fluorescent materials and rare earth-based fluorescent materials green plasma composition for a plasma display panel. The method of claim 6, The fluorescent material is at least one plasma display selected from the group consisting of BaAl ₁₂ O ₁₉ : Mn, (BaSrMg) O.aAl ₂ O ₃ : Mn, YBO ₃ : Tb, and (Y, Gd) BO ₃ : Tb. Green phosphor composition for panel. The method of claim 6, The phosphor is 50 to 100 parts by weight based on 100 parts by weight of the green phosphor composition green phosphor composition for a plasma display panel. A plasma display panel having a phosphor layer comprising a red phosphor layer, a green phosphor layer, and a blue phosphor layer, The green phosphor layer comprises a green phosphor composition according to any one of claims 1 to 8. The method of claim 9, The plasma display panel A first substrate including an address electrode, a dielectric layer covering the address electrode, a barrier rib formed on an entire surface of the dielectric layer, and a red phosphor layer, a blue phosphor layer, and a green phosphor layer positioned in a discharge cell partitioned by the barrier rib; And A second substrate including a display electrode including a transparent electrode and a bus electrode, a transparent dielectric layer formed on a front surface of the display electrode and a protective film coated on the transparent dielectric layer Plasma display panel comprising a.

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