KR101496448B1 - Medium-permittivity dielectrics with excellent temperature stability and plasma light source using the same - Google Patents

Abstract

The present invention discloses a dielectric material having excellent temperature stability and a medium permittivity of about 150-200; and a plasma light source using the dielectric material. According to the present invention, the dielectric material is represented by formula 1: X(CaTiO_3)+Y(MgTiO_3)+Z(BiAlO_3) (X>0, Y>0, Z>0, X+Y+Z=1), formula 2: W(CaTiO_3)+X(MgTiO_3)+Y(BiAlO_3)+Z(LaAlO_3) (W>0, X>0, Y>0, Z>0, W+X+Y+Z=1), or formula 3: V(CaTiO_3)+W(SrTiO_3)+X(MgTiO_3)+Y(BiAlO_3)+Z(LaAlO_3) (V>0, W>0, X>0, Y>0, Z>0, V+W+X+Y+Z=1).

Description

TECHNICAL FIELD [0001] The present invention relates to a medium-dielectric constant dielectric material excellent in temperature stability, and a plasma light source using the medium dielectric constant dielectric material. [0002]

The present invention relates to a medium-to-high dielectric constant dielectric constant having a relative dielectric constant (hereinafter, referred to as dielectric constant) of approximately 150 to 200 that can be used for a light source using a plasma phenomenon such as a plasma display panel (PDP) To a plasma light source.

Conventionally, a dielectric material used for a plasma light source mainly uses a glass or MgO single crystal having a large secondary electron emission coefficient. However, due to the low dielectric constant of about 10, these materials can not increase the wall charge on the dielectric surface located in the discharge vessel. Therefore, when these materials are used, there are restrictions on the number of colliding plasma ions or electrons present in the discharge space with mercury or xenon gas, and as a result, there is a limitation in increasing the light efficiency.

1 schematically shows a general plasma light source.

1, a generally used plasma light source has the following structure. First, phosphors are coated on the inner surface of the glass tube 110 sealed at both ends. An inert gas 120 such as argon (Ar) or neon (Ne), seed electrons 130, and mercury (Hg) 140 are mixed in the glass tube 110, Is enclosed. In addition, external electrodes 150 of various shapes are formed on both ends of the glass tube 110 and coated with a conductive layer such as silver or carbon. When a high-voltage AC power source AC is applied to the conductive layer of the external electrode 150 formed at both ends of the glass tube, both ends of the glass tube 110 contacting the electrode 150 serve as a dielectric, Thereby forming an electric field.

More specifically, when the polarity of the voltage applied to the left end of the glass tube to which the electrode is applied is positive, the seed electrons 130 are accumulated in the left glass tube 160 to which the electrode 150 is applied, Polarity, positive ions are accumulated in the inside of the right glass tube 161. At this time, the accumulated positive ions are generated by transition of the enclosed inert gas into an unstable cation or an ionized gas having a positive polarity of metastable state by the seed electrons 130 accelerated by a strong external electric field. The wall charges accumulated in the left and right glass tube inner parts 160 and 161 are caused to reciprocate at both ends of the glass tube 110 by the inversion of the continuous polarity by the AC electric field. At this time, the reciprocating wall charge induces an excitation light emission process of the mercury gas collided with the mercury gas 140 enclosed with the inert gas, and the ultraviolet rays induced during the light emission process cause the fluorescent material coated on the inner wall of the glass tube 110 It is excited and turned into visible light, and visible light is emitted to the outside.

In this case, in order to increase the brightness of the conventional plasma light source, there is a method of increasing the amount of wall charge by increasing the electrode application area of the both end glass tubes coated with the electrodes. However, such an increase in electrode coating area has practical limitations because it reduces the light emitting area.

Background art related to the present invention is a composition for a plasma display panel dielectric disclosed in Korean Patent Laid-Open Publication No. 10-2010-0005432 (published on January 15, 2010), and a plasma display panel comprising the same.

One object of the present invention is to increase the efficiency of a plasma light source by using a dielectric material having a high dielectric constant. By analyzing the physical phenomenon occurring in a dielectric electrode when power is applied to a light source, dielectric constant and dielectric loss And to provide a dielectric material having a medium dielectric constant capable of maintaining stability.

Another object of the present invention is to provide a plasma light source to which the above dielectric is applied.

In order to achieve the above object, a dielectric according to an embodiment of the present invention is represented by the following equation (1).

[Formula 1]

_{X (CaTiO 3) + Y (} MgTiO 3) + Z (BiAlO 3) (X> 0, Y> 0, Z> 0, X + Y + Z = 1)

In this case, it is more preferable that X: 0.5 to 0.6, Y: 0.15 to 0.25, and Z: 0.2 to 0.3.

The dielectric may have a dielectric constant of 144 to 155 at 20 to 100 ° C and a dielectric constant reduction rate of less than 10% at a temperature of 100 ° C relative to a dielectric constant of 20 ° C.

In order to achieve the above object, a dielectric according to another embodiment of the present invention is expressed by the following equation (2).

[Formula 2]

_{W (CaTiO 3) + X (} MgTiO 3) + Y (BiAlO 3) + Z (LaAlO 3) (W> 0 X> 0, Y> 0, Z> 0, W + X + Y + Z = 1)

In this case, it is more preferable that W: 0.5 to 0.6, X: 0.15 to 0.25, Y: 0.15 to 0.25, and Z = 0.01 to 0.1.

The dielectric may have a dielectric constant of 144 to 155 at 20 to 100 ° C and a dielectric constant reduction rate of less than 10% at a temperature of 100 ° C relative to a dielectric constant of 20 ° C.

In order to achieve the above object, a dielectric according to another embodiment of the present invention is expressed by the following equation (3).

[Formula 3]

_{V (CaTiO 3) + W (} SrTiO 3) + X (MgTiO 3) + Y (BiAlO 3) + Z (LaAlO 3) (V> 0, W> 0 X> 0, Y> 0, Z> 0, V + W + X + Y + Z = 1)

It is more preferable that V is 0.15 to 0.4, W is 0.15 to 0.4, X is 0.15 to 0.25, Y is 0.1 to 0.2, and Z is 0.05 to 0.15. In addition, the dielectric material has a polygonal particle shape with a cross-section of a pentagonal shape or more at a mole fraction (W) of SrTiO ₃ of 0.36 or more, and the particles can be matched with each other.

In addition, the dielectric may have a dielectric constant of 160 to 185 at 20 to 100 ° C and a dielectric constant reduction rate of less than 10% at 100 ° C relative to a dielectric constant of 20 ° C.

According to another aspect of the present invention, there is provided a plasma light source comprising: a glass tube coated with a fluorescent material on an inner peripheral surface thereof and filled with an inert gas and a metal vapor; And a hollow electrode having one end coupled to the glass tube and the other end sealed, wherein the hollow electrode includes a dielectric electrode and a metal electrode formed on a surface of the dielectric electrode, And one dielectric.

In the case of the dielectric according to the present invention, the dielectric constant is about 150 to about 190, the dielectric loss is low, and the dielectric constant is not greatly reduced even at a high temperature of about 100 DEG C, so that the temperature stability can be secured.

In addition, the dielectric according to the present invention has a high secondary electron emission coefficient, and when the same dielectric area is used as compared with the case of using a MgO single crystal or a glass dielectric having a dielectric constant near 10, And the collision with the mercury gas is increased by moving the plasma ions, so that the luminance efficiency of the lamp per unit power can be greatly increased.

Further, in the case of the dielectric according to the present invention, since the driving voltage has a value of 700 to 900 Vrms and high brightness is obtained at a relatively low voltage of 770 Vrms at 19 Watt driving in an optimized composition, There is an advantage that it can be used as a discharge lamp.

1 schematically shows a general plasma light source.
2 shows an example of a process for producing the dielectric of the present invention.
FIG. 3 shows the change in dielectric constant and dielectric loss according to the temperature change of the dielectric according to Example 1. FIG.
FIG. 4 shows changes in dielectric constant and dielectric loss according to the temperature change of the dielectric according to Example 2. FIG.
5 shows the change of the dielectric constant and dielectric loss according to the temperature change of the dielectric according to the third embodiment.
6 shows the change of the dielectric constant and the dielectric loss according to the temperature change of the dielectric according to the fourth embodiment.
7 schematically shows a structure of a plasma light source applied to an embodiment of the present invention.
FIG. 8 is a photograph of a dielectric according to the present invention manufactured in a cylindrical shape for use as a dielectric electrode of the plasma light source shown in FIG.
Fig. 9 shows the microstructure of the sintered examples 1 to 4. Fig.

BRIEF DESCRIPTION OF THE DRAWINGS The advantages and features of the present invention, and how to achieve them, will be apparent from the following detailed description of embodiments and drawings. However, the present invention is not limited to the embodiments disclosed below, and may be embodied in various other forms. The embodiments disclosed below are merely provided to fully disclose the scope of the invention to a person having ordinary skill in the art to which the present invention belongs. The invention is only defined by the scope of the claims.

Hereinafter, the medium-dielectric constant dielectric excellent in temperature stability according to the present invention and a plasma light source using the same will be described in detail.

Ions or electrons collide at a high speed on a surface of a dielectric exposed in a discharge space generated when a discharge is initiated in a glass tube due to application of a high voltage and the temperature of the dielectric increases due to a heat generation due to dielectric loss in a dielectric to which a high voltage is applied . Therefore, if the dielectric constant at room temperature can not be maintained at a high temperature, the efficiency of the light source is changed in accordance with the temperature change. In order to prevent this, the temperature stability of the dielectric constant and the measures for reducing the dielectric loss at the actual driving temperature need.

However, as the dielectric constant of conventional dielectric materials increases, the temperature stability of the dielectric constant rapidly decreases, and the dielectric loss also increases, making it difficult to maintain a stable optical efficiency in actual operation. In addition, a thermoelectronic emission type fluorescent lamp or a cold cathode lamp using a metal electrode can increase the light efficiency by increasing the amount of collision with mercury or xenon by using electron emission by thermal organic or electric field organic. However, Since the secondary electron emission coefficient is low due to the use of an insulator such as a dielectric, there is a limit to increase the light efficiency.

Accordingly, in order to solve the above problems, the present invention has been made to produce a dielectric having a high temperature stability at a high temperature and a dielectric loss at a high temperature, and also to increase the light efficiency by selecting a component having a high secondary electron emission coefficient.

In order to achieve the object of the present invention as described above, a dielectric material having a new composition is designed and manufactured based on existing data on the constituent materials, and dielectric properties are measured. When the electrode is used as a plasma light source of the dielectric material, And their suitability was confirmed.

Generally, materials such as MgO, Bi ₂ O ₃ and TiO ₂ have low band gap energy and are easy to emit secondary electrons and are typical materials used for PDP, oxide semiconductor or photocatalyst. Therefore, when a compound is manufactured using these materials, secondary electrons can be easily induced in the discharge space when used as an electrode of a plasma light source, as compared with other materials, thereby increasing the efficiency of the light source. The dielectric was designed.

A dielectric material having negative temperature stability (a phenomenon in which the dielectric constant decreases with increasing temperature) and a dielectric material having a positive temperature stability (a phenomenon in which the dielectric constant increases with increasing temperature) in order to secure the high temperature stability of the dielectric constant or dielectric loss So that a composition having desired dielectric constant and temperature stability is made possible.

Generally, the dielectric constant (epsilon r) at room temperature and the temperature coefficient according to the dielectric constant depending on the dielectric material are summarized in Table 1 below. In general, the temperature coefficient of capacitance is determined by the following equation

C _ε : Temperature coefficient of permittivity

α _L : coefficient of linear expansion

[Table 1]

As shown in Table 1, SrTiO ₃ and CaTiO ₃ having a perovskite structure exhibit a negative property that their dielectric constant decreases with increasing temperature. They exhibit a relatively high dielectric constant, and MgTiO ₃ and Al ₂ O ₃ have a dielectric constant of And the other is the same. In addition, the band Negev energy is small, the secondary components such as Bi ₂ O ₃ or La ₂ O ₃ that is an electron emission is expected to facilitate the Al ₂ O ₃ and with BiAlO ₃ or Fe lobe determination of the Sky agent, such as LaAlO ₃ structure Therefore, it is easy to form a solid solution with SrTiO ₃ , CaTiO ₃ and the like as the main materials, and thus it is included in the composition to achieve the object of the present invention. A small amount of MgTiO ₃ , which represents a crystal structure of imenite as a dielectric material having a positive characteristic, was added to alleviate the temperature coefficient of the dielectric having negative characteristics. MgTiO ₃ has a dielectric property of positive characteristics, but its permittivity is low. Therefore, when the amount of MgTiO ₃ is increased, the total permittivity is decreased. Therefore, the amount of MgTiO ₃ is determined through a preliminary experiment so that an optimum amount of MgTiO ₃ is added.

As a result of the above-described study, inventors of the present invention have invented the dielectrics represented by the following formulas 1 to 3.

[Formula 1]

_{X (CaTiO 3) + Y (} MgTiO 3) + Z (BiAlO 3) (X> 0, Y> 0, Z> 0, X + Y + Z = 1)

[Formula 2]

_{W (CaTiO 3) + X (} MgTiO 3) + Y (BiAlO 3) + Z (LaAlO 3) (W> 0 X> 0, Y> 0, Z> 0, W + X + Y + Z = 1)

[Formula 3]

_{V (CaTiO 3) + W (} SrTiO 3) + X (MgTiO 3) + Y (BiAlO 3) + Z (LaAlO 3) (V> 0, W> 0 X> 0, Y> 0, Z> 0, V + W + X + Y + Z = 1)

It is more preferable that X: 0.5 to 0.6, Y: 0.15 to 0.25 and Z: 0.2 to 0.3 in the formula 1, W: 0.5 to 0.6, X: 0.15 to 0.25, Y: 0.15 to 0.25, and Z More preferably 0.1 to 0.4, W: 0.15 to 0.25, Y: 0.1 to 0.2, and Z: 0.05 to 0.15 in Formula 3, When the values of V, W, X, Y, and Z, which are the molar fractions, fall within the above range, the dielectric loss can be reduced to 10% or less even at a temperature of up to 100 캜 while the dielectric loss is small, .

In the case of the dielectric material represented by the formula 1, the relative dielectric constant (hereinafter, referred to as dielectric constant) is from 144 to 155 at 20 to 100 ° C., the dielectric constant reduction rate at 100 ° C. is less than 10% .

In the case of the dielectric material represented by the formula 2, the dielectric constant is from 144 to 155 at 20 to 100 ° C, the dielectric constant reduction rate at 100 ° C is less than 10% relative to the dielectric constant at 20 ° C, and the dielectric loss is as low as about 0.05%.

In the case of the dielectric represented by Formula 3, the dielectric constant is 160 to 185 at 20 to 100 ° C, the dielectric constant reduction rate at 100 ° C is less than 10% relative to the dielectric constant at 20 ° C, and the dielectric loss is as low as about 0.05%.

On the other hand, in the case of the dielectrics represented by the formulas 1 to 3, they may have mainly a rectangular cross-sectional particle shape.

However, it is transformed into a particle form of a polygonal shape close to a circle more than a pentagon and the mole fraction (W) of SrTiO ₃ in the dielectric is increased to more than 0.36, which is represented by the equation (3). Through this, there is almost no space between the particles and the particles, and the particles can be matched. As described above, by the existence of the fine particles being matched, the charge / discharge effect of the dielectric electrode located in the discharge space can be increased.

2 shows an example of a process for producing the dielectric of the present invention.

Referring to FIG. 2, in order to manufacture the dielectric material according to the present invention, first, a raw material such as CaCO ₃ , MgCO ₃ , Bi ₂ O ₃ , TiO ₂ , and α-Al ₂ O ₃ , (S210). Next, the weighed raw materials are put into a container, followed by mixing and grinding by a wet ball mill or the like (S220). Thereafter, the mixed powder is dried (S230). Next, calcination is performed at approximately 1100 to 1150 캜 for 2 to 4 hours (S240). Thereafter, a ball mill is performed again by a wet ball mill or the like in order to crush the calcined powder (S250). In this process, a binder such as PVA is added and mixed (S260). Thereafter, the dried powder is squeezed (S270) and formed into a predetermined shape such as a disk (S280). Thereafter, the formed body is heated to remove the binder, sintered at about 1150 to 1300 ° C for about 2 hours, and then cooled by a method such as low-temperature cooling (S290).

Fig. 2 is only one example of a rice process for making dielectrics, and a variety of known methods for making dielectrics from raw materials can be used.

In order to utilize the dielectric material as a dielectric electrode or the like of the plasma light source, both surfaces of the dielectric material may be polished (S300), and the electrode firing process may be performed (S310).

A plasma light source in which a dielectric according to the present invention is used as a material of a dielectric electrode includes a glass tube and a hollow electrode.

The glass tube may have a U-shape or a square shape, and may be formed of borosilicate, non-lead glass, or quartz glass. Phosphors are coated on the inner peripheral surface of the holding tube. An inert gas such as argon (Ar) or neon (Ne) is mixed with mercury (Hg) gas or xenon (Xe) gas in the glass tube.

The hollow electrode is bonded to both ends of the glass tube, one end is coupled to the glass tube, and the other end is sealed. The hollow electrode includes a dielectric electrode and an external electrode formed on the surface of the dielectric electrode. The external electrode may be formed of silver (Ag) excellent in electrical stability. And, the dielectric electrode can be formed of the dielectric according to the present invention described above.

Example

Hereinafter, the configuration and operation of the present invention will be described in more detail with reference to preferred embodiments of the present invention. It is to be understood, however, that the same is by way of illustration and example only and is not to be construed in a limiting sense.

The contents not described here are sufficiently technically inferior to those skilled in the art, and a description thereof will be omitted.

Example 1

_{X (CaTiO 3) + Y (} MgTiO 3) + Z (BiAlO 3): X = 0.56, Y = 0.19, Z = 0.25

Designed to fit into a relatively composition formula as the CaTiO ₃ having a dielectric constant at high temperature to above as the main _{component, CaCO 3, MgCO 3, Bi} 2 O 3, TiO 2, and then the basis weight by using Al ₂ O ₃ raw material α-, Using a ZrO ₂ ball stabilized with Y ₂ O ₃ , mixing and grinding were carried out for 24 hours using a ball mill using ultra pure water. The mixed powders were dried and then calcined at 1120 ° C. for 3 hours using an alumina crucible. To crush the calcined powder, ball milling was performed for 72 hours using ultrapure water. Polyvinyl acetate (PVA) dissolved in ultrapure water was added 3 hours before completion of the ball milling process, and the mixture was mixed for 3 hours and dried. Was cut into 80 mesh pieces and molded into a disc shape by a press. The compact was sintered on an alumina substrate.

The optimum sintering temperature was maintained at 1150 ~ 1300 ℃ for 2 hours and then cooled down.

After the sintered specimens were taken out and polished on both sides, the electrode was coated and electrodes were baked at 590 ° C. Then dielectric constant and dielectric loss were measured according to the dielectric properties and temperature changes at room temperature.

The composition of Example 1 will be described below using measurement results. Table 2 shows the change of dielectric constant (dielectric constant) and dielectric loss value at room temperature according to sintering temperature change of fabricated specimen.

[Table 2]

As shown in Table 2, the change in permittivity and the dielectric loss according to the temperature change were measured for a specimen sintered at 1150 ° C for 2 hours with a high uniformity of the microstructure and a relatively high dielectric constant and dielectric loss coefficient. Respectively.

As shown in FIG. 3, the dielectric constant decreases with increasing temperature at room temperature, and the dielectric loss increases at 150 ° C. However, when used as a dielectric electrode of a plasma light source, the surface temperature of the dielectric electrode rises to about 100 ° C., so that a dielectric constant of 144 at 100 ° C. and a dielectric loss of 0.05% are maintained. Therefore, It can be seen that a high charge / discharge efficiency can be expected.

Example 2

_{W (CaTiO 3) + X (} MgTiO 3) + Y (BiAlO 3) + Z (LaAlO 3): W = 0.56, X = 0.19, Y = 0.2, Z = 0.05

Example 2 In order to examine the influence of the La compound which increases the secondary electron emission coefficient used as the electrode material of the scanning electron microscope was added with LaAlO composition of the _third aspect BiAlO _3, to meet the composition formula is designed as above, CaCO _3, Weighed using a raw material of MgCO ₃ , Bi ₂ O ₃ , TiO ₂ , α-Al ₂ O ₃ and La ₂ O ₃ and then mixed with a ball mill using ultra pure water using a Y ₂ O ₃ stabilized ZrO ₂ ball And grinding were carried out for 24 hours. The mixed powders were dried and then calcined at 1120 ° C. for 3 hours using an alumina crucible. In order to crush the calcined powder, ball milling was performed for 72 hours using ultrapure water. PVA dissolved in ultrapure water was added 3 hours before completion of the ball milling process, mixed for 3 hours and dried. The dried powder was kept in 80 mesh And then formed into a disc shape by a press. The compact was sintered on an alumina substrate. The optimum sintering temperature was maintained at 1150 ~ 1300 ℃ for 2 hours and then cooled down.

The sintered specimens were taken out and polished on both sides. The electrode was coated on the electrodes at 590 ℃, and dielectric constant and dielectric loss were measured at room temperature.

The composition of Example 2 will be described below using measurement results. Table 3 shows the change of dielectric constant and dielectric loss at room temperature according to sintering temperature of fabricated specimens.

[Table 3]

As shown in Table 3, the change of the dielectric constant and the dielectric loss according to the temperature change of the specimen sintered at 1180 ° C for 2 hours, which has a high uniformity of the microstructure and a comparatively good dielectric constant and dielectric loss coefficient, Respectively.

Referring to FIG. 4, the dielectric constant decreases with increasing temperature at room temperature, and the phenomenon of increase in dielectric loss at 150 ° C. disappears. Therefore, it can be seen that the addition of La reduces the dielectric constant but increases the dielectric constant and the temperature stability of the dielectric loss. In addition, when used as a dielectric electrode of a plasma light source, the surface temperature of the dielectric electrode rises up to 100 ° C., so that a dielectric constant of 128 and a dielectric loss value of 0.05% are maintained at 100 ° C. Therefore, 10) can be expected.

Example 3

_{V (CaTiO 3) + W (} SrTiO 3) + X (MgTiO 3) + Y (BiAlO 3) + Z (LaAlO 3): V = 0.28, W = 0.28, X = 0.19, Y = 0.15, Z = 0.10

In addition to developing the dielectric constant is reduced as La is added on the basis of the results of Example 2 that the stability of the dielectric loss increases, a slight amount of LaAlO ₃ in order to increase the dielectric constant value and to stabilize the dielectric loss properties at high temperatures a SrTiO ₃ showing a high dielectric constant characteristics at the rising and Table 1 was added to some of the alternate CaTiO _3. In order to conform to the composition formula as described above, it is weighed using SrCO ₃ , CaCO ₃ , MgCO ₃ , Bi ₂ O ₃ , TiO ₂ , α-Al ₂ O ₃ and La ₂ O ₃ raw materials and then stabilized with Y ₂ O _{3 2} ball, using ultra pure water, and mixing and grinding were carried out for 24 hours using a ball mill. The mixed powders were dried and then calcined at 1120 ° C. for 3 hours using an alumina crucible. For pulverizing the calcined powder, ball milling was performed for 72 hours using ultrapure water. PVA dissolved in ultrapure water was added 3 hours before the completion of the ball milling process. The powder was mixed for 3 hours and dried. The dried powder was kept in 80 mesh And formed into a disc shape by a press. The compact was sintered on an alumina substrate. The optimum sintering temperature was maintained at 1150 ~ 1300 ℃ for 2 hours and then cooled down. The sintered specimens were taken out and polished on both sides. The electrode was coated on the electrodes at 590 ℃, and dielectric constant and dielectric loss were measured at room temperature.

The composition of Example 3 will be described below using measurement results. Table 3 shows the change of dielectric constant and dielectric loss at room temperature according to sintering temperature of fabricated specimens.

[Table 4]

According to the result of Table 4, the change of the dielectric constant and the dielectric loss according to the temperature change of the specimen sintered at 1290 ° C for 2 hours, which has a high uniformity of the microstructure and a relatively good dielectric constant and dielectric loss coefficient, Respectively.

Referring to FIG. 4, the dielectric constant decreases as the temperature increases at room temperature, and the dielectric loss decreases as the temperature increases. When used as a dielectric electrode of a plasma light source, the surface temperature of the dielectric electrode rises to 100 ° C., so that a dielectric constant of 175 and a dielectric loss of 0.09% at 100 ° C. are maintained. Therefore, It can be seen that a high charge / discharge efficiency can be expected.

Example 4

_{V (CaTiO 3) + W (} SrTiO 3) + X (MgTiO 3) + Y (BiAlO 3) + Z (LaAlO 3): V = 0.20, W = 0.36, X = 0.19, Y = 0.125, Z = 0.125

Based on the results of Example 2 in which the dielectric constant decreases as the La is added and the stability of the dielectric loss is increased and the dielectric loss is increased in Example _{3 where} the addition of SrTiO ₃ increases the dielectric constant, It was allowed, a slight increase in the amount of addition of SrTiO ₃ has the highest dielectric constant characteristics in Table 1, and to slightly increase the amount of LaAlO ₃ in order to stabilize, to compensate for the dielectric constant decreases with increasing amount of LaAlO _3. In order to conform to the composition formula as described above, it is weighed using SrCO ₃ , CaCO ₃ , MgCO ₃ , Bi ₂ O ₃ , TiO ₂ , α-Al ₂ O ₃ and La ₂ O ₃ raw materials and then stabilized with Y ₂ O _{3 2} ball, using ultra pure water, and mixing and grinding were carried out for 24 hours using a ball mill. The mixed powders were dried and then calcined at 1120 ° C. for 3 hours using an alumina crucible. For pulverizing the calcined powder, ball milling was performed for 72 hours using ultrapure water. PVA dissolved in ultrapure water was added 3 hours before the completion of the ball milling process. The powder was mixed for 3 hours and dried. The dried powder was kept in 80 mesh And formed into a disc shape by a press. The compact was sintered on an alumina substrate.

The optimum sintering temperature was maintained at 1150 ~ 1300 ℃ for 2 hours and then cooled down. The sintered specimens were taken out and polished on both sides. The electrode was coated on the electrodes at 590 ℃, and dielectric constant and dielectric loss were measured at room temperature.

The composition of Example 4 will be described using measurement results. Table 5 shows the change of dielectric constant and dielectric loss value at room temperature according to sintering temperature change of fabricated specimens.

[Table 5]

As shown in Table 5, the dielectric constant is slightly reduced, but the dielectric loss is greatly reduced and stabilized as compared with Example 3.

The results of measurement of the change of the dielectric constant and the dielectric loss according to the temperature change for the sample sintered at 1240 ° C for 2 hours with a high uniformity of the microstructure and relatively good dielectric constant and dielectric loss factor according to the results of Table 5 are shown in FIG. Respectively.

Referring to FIG. 5, the dielectric constant decreases as the temperature increases at room temperature, and the dielectric loss decreases as the temperature increases. As the dielectric electrode of the plasma light source, the temperature rise rises up to 100 ° C., and the dielectric constant of 161 and the dielectric loss value of 0.04% at 100 ° C. are maintained. Therefore, compared with the conventional glass dielectric electrode (dielectric constant ~ 10) It can be seen that the efficiency can be expected.

Example 5

In order to investigate the effect of the dielectric materials prepared in Examples 1 to 4 on the efficiency of the light source when used as an electrode material of a plasma light source, the apparatus as shown in FIG. 7 was used to measure the luminance change according to the applied electric power. The apparatus of FIG. 7 will be described as follows. A flange 740 for inserting and fixing a cylindrical dielectric electrode 730 at both ends of a glass tube 720 having a length of 1100 mm and a diameter of 8.0 mm and having an inner wall coated with the phosphor 710 is molded on both ends of the lamp outer wall And a glass plate 760 provided with exhaust pipes and exhaust pipes 750 and 751 for filling with neon / argon gas and mercury gas at upper and lower ends of the dielectric electrode 730 for vacuum exhaust and gas and mercury gas injection. An Ag electrode 770 is applied to the outer wall of the hollow dielectric electrode 730 to apply electricity. The glass plate 760 is bonded to the glass plate 760 provided with the exhaust pipes 750 and 751 by a glass frit for sealing on the dielectric electrode 730. The air inside the glass tube 720 is exhausted at 10 ^-5 torr by the exhaust pipe 750 installed at the upper side and then the valve connected to the vacuum pump is closed and the exhaust pipe 751 installed at the lower part in a state where the vacuum is maintained Neon and argon gas are mixed at a ratio of 97: 3, and the glass tube is injected at 20 torr, and 2 mg of mercury gas is injected. When this process is completed, both ends of the exhaust pipes 750 and 751 are sealed by a torch burner to complete a plasma discharge tube. FIG. 8 shows a photograph of a cylindrical dielectric electrode fabricated using the compositions of Examples 1 to 4 provided at both ends to facilitate understanding. At this time, the dielectric electrode 810 has dimensions of 18 mm in inner diameter 8.3 mm and outer diameter 10 mm, and has the same dimensions in all the compositions, and the outer wall is coated with the Ag electrode 820.

For the plasma discharge, a high voltage generator (NF corporation) was connected to the silver electrode coated on the upper and lower dielectric electrodes 2, and a voltage of 700 to 900 V rms was applied at 60 to 70 kHz, -7A) to measure the luminance per input power and compare the values.

Table 6 shows the change of the luminance value according to each input power when the plasma discharge tube was manufactured using the composition of Example 1. [

[Table 6]

Referring to Table 6, the luminance increased with the power increase, and a high brightness of 28000 Lv was obtained at 39 watts. On the other hand, in the case of a discharge lamp made of a commercially available glass dielectric, a plasma discharge lamp having an outer diameter of 8 mm and a length of 1100 mm has a luminance of 5000 Lv when an 8 Watt input is obtained, while a dielectric electrode having a composition of Example 1 has a luminance of 7452 Lv Loses. It can be seen that the optical efficiency is increased by 49% by using the high dielectric constant dielectric electrode as compared with the glass dielectric electrode. Also, the maximum value is shown at a power of 944 (Lv / W) per unit power when 17 Watt is input.

Table 7 shows the change of the luminance value according to each input power when the plasma discharge tube was manufactured using the composition of Example 2. [

[Table 7]

Referring to Table 7, the brightness increased with the power increase, and a high brightness of 26360 Lv was obtained at 34 watts. On the other hand, in the case of a discharge lamp made of a commercially available glass dielectric, a plasma discharge lamp having an outer diameter of 8 mm and a length of 1100 mm has a luminance of 5000 Lv when an 8 Watt input is obtained, while a dielectric electrode having a composition of Example 2 has a luminance of 6875 Lv . It can be seen that the optical efficiency is increased by 37.5% by using the high dielectric constant dielectric electrode as compared with the glass dielectric electrode. Also, the maximum value is 901 (Lv / W) per unit power when 18 Watt is input.

Compared with the results of Example 1, the dielectric constant of the composition of Example 1 was 155, and the dielectric constant of Example 2 was about 138 to 9, which was lower than that of the dielectric of Example 1, And the number of collisions with the mercury gas in the discharge space is reduced, thereby decreasing the light efficiency.

Table 8 shows the change of the luminance value according to each input power when the plasma discharge tube was manufactured using the composition of Example 3. [

[Table 8]

As shown in Table 8, the brightness increased with the power increase, and a high brightness of 27010 Lv was obtained at 32 watts. This shows an increased value in comparison with the luminance of 25875 Lv at 33 watts in Example 1 and 24680 Lv at 31 watts in Example 2. [ On the other hand, in the case of a discharge lamp made of a commercially available glass dielectric, a plasma discharge lamp having an outer diameter of 8 mm and a length of 1100 mm has a luminance of 5000 Lv when an 8 Watt input is obtained, whereas a dielectric electrode having a composition of Example 1 has a luminance of 6950 Lv . It can be seen that the optical efficiency is increased by 39% by using the high dielectric constant dielectric electrode as compared with the glass dielectric electrode. Also, the maximum value is 958 (Lv / W) per 12 Watt input power per unit power.

Since the dielectric constant is the highest at 180 in Examples 1 and 2, the maximum efficiency is increased by the increased dielectric constant, but the efficiency at low input power is higher than that in Example 1 due to the relatively high dielectric loss at room temperature and below 100 ° C. However, it can be seen that, at a high input power of 20 watt or more at which the temperature of the dielectric electrode rises, the luminance per input power is obtained due to the low dielectric loss coefficient.

Table 9 shows the change of the luminance value according to each input power when the plasma discharge tube was manufactured using the composition of Example 4. [

[Table 9]

As shown in Table 9, the luminance increased with the power increase, and a high luminance of 26850 Lv was obtained at 32 watts. On the other hand, in the case of a discharge lamp made of a commercially available glass dielectric, a plasma discharge lamp having an outer diameter of 8 mm and a length of 1100 mm has a luminance of 5000 Lv when an 8 Watt input is obtained, while a dielectric electrode having a composition of Example 4 has a luminance of 7058 Lv . It can be seen that the optical efficiency is increased by 41% by using the dielectric electrode having high dielectric constant as compared with the glass dielectric electrode. Also, the maximum value of the luminance per unit power at the input of 19 Watt is 982 (Lv / W).

As a material having a dielectric constant value (dielectric constant of 168) intermediate between Examples 1 and 3, it can be seen that the dielectric loss at room temperature and 100 deg. C is greatly reduced as compared with Example 3. Therefore, it can be seen that the luminance per unit electric power at the low electric power is increased as compared with the Embodiment 3, and the maximum efficiency is shown at the high electric power (19 watts) as compared with Examples 1 to 3. This phenomenon is considered to be related to the change of the microstructure as well as the low dielectric loss at room temperature and high temperature.

Fig. 9 shows changes in the microstructure of Examples 1 to 4 sintered at the optimum sintering temperature.

The microstructure of Figs. 9 (a) to 9 (d) corresponds to those of the compositions of Examples 1 to 4. The difference from FIG. 9 is that the material having a rectangular cross-sectional particle shape in the compositions of Examples 1 to 3 is deformed into a polygonal-like particle shape having a pentagonal shape or more in the composition of Example 4, It can be seen that the particles are almost not present in comparison with the examples 1 to 3 and the particles are matched. It can be seen that such a maximum efficiency is obtained because the charge / discharge effect of the dielectric electrode located in the discharge space is increased by the presence of the fine particles of about 1 mu m in matched state.

The plasma display panel is advantageous in that it can be easily driven under a stable voltage as compared with a plasma discharge lamp manufactured from a glass dielectric with a high voltage of 8 Watt to 1200 Vrms at an input voltage of 770 Vrms at 19 watts of a dielectric having a composition according to Example 4 manufactured by the present invention Respectively.

While the present invention has been described in connection with what is presently considered to be practical exemplary embodiments, it is to be understood that the invention is not limited to the disclosed embodiments, but, on the contrary, It is to be understood that the invention may be embodied in other specific forms without departing from the spirit or essential characteristics thereof. It is therefore to be understood that the above-described embodiments are illustrative in all aspects and not restrictive.

110: Glass tube 120: Inert gas
130: Seed Electronics 140: Mercury Gas
150: external electrode 160: left glass tube inner
161: inside right glass tube
710: Phosphor 720: Glass tube
730: dielectric electrode 740: flange
750, 751: Exhaust pipe 760: Glass plate
770: Ag electrode
810: Dielectric electrode 820: Ag electrode

Claims (11)

delete A dielectric represented by the following formula (1).
[Formula 1]
_{X (CaTiO 3) + Y (} MgTiO 3) + Z (BiAlO 3) (X: 0.5 ~ 0.6, Y: 0.15 ~ 0.25, Z: 0.2 ~ 0.3, X + Y + Z = 1)
3. The method of claim 2,
The dielectric
(Dielectric constant) of from 144 to 155 at 20 to 100 占 폚,
Wherein the dielectric constant reduction rate at 100 占 폚 relative to the dielectric constant at 20 占 폚 is 10% or less.
delete (2).
[Formula 2]
_{W (CaTiO 3) + X (} MgTiO 3) + Y (BiAlO 3) + Z (LaAlO 3) (W: 0.5 ~ 0.6, X: 0.15 ~ 0.25, Y: 0.15 ~ 0.25, Z: 0.01 ~ 0.1, W + X + Y + Z = 1)
6. The method of claim 5,
The dielectric
A dielectric constant of 144 to 155 at 20 to 100 DEG C,
Wherein the dielectric constant reduction rate at 100 占 폚 relative to the dielectric constant at 20 占 폚 is 10% or less.
delete (3).
[Formula 3]
_{V (CaTiO 3) + W (} SrTiO 3) + X (MgTiO 3) + Y (BiAlO 3) + Z (LaAlO 3) (V: 0.15 ~ 0.4, W: 0.15 ~ 0.4, X: 0.15 ~ 0.25, Y: 0.1 to 0.2, Z: 0.05 to 0.15, V + W + X + Y + Z = 1)
9. The method of claim 8,
Said dielectric is in the molar fraction (W) of said SrTiO ₃ 0.36 or more, the cross section has the form of particles of at least 5 square polygon, a dielectric characterized in that the particles are matched with each other.
9. The method of claim 8,
The dielectric
A dielectric constant of 160 to 185 at 20 to 100 占 폚,
Wherein the dielectric constant reduction rate at 100 占 폚 relative to the dielectric constant at 20 占 폚 is 10% or less.
A glass tube to which a phosphor is applied on an inner peripheral surface, and an inert gas and a metal vapor are mixed and filled in the glass tube; And
And a hollow electrode, one end of which is coupled to the glass tube and the other end of which is sealed,
Wherein the hollow electrode includes a dielectric electrode and a metal electrode formed on a surface of the dielectric electrode,
Wherein said dielectric electrode comprises a dielectric of any one of claims 2 to 3, 5 to 6, and 8 to 10.

Images