JP2008214144A - Dielectric composition, dielectric using the dielectric composition and dielectric paste - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a dielectric composition capable of obtaining a dense fired film on soda lime glass containing no lead, free from the discoloration of a silver electrode and capable of obtaining low specific dielectric constant and to provide a dielectric and a dielectric paste. <P>SOLUTION: The dielectric composition comprises glass powder prepared by mixing glass powder containing bismuth and no lead and no alkali with glass powder containing no lead and no bismuth, and at least one or more kind of inorganic oxide powder of quartz, alumina, zirconia, zircon, forsterite, titanium oxide and heat resistant black pigment. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a dielectric composition, a dielectric, and a dielectric paste of a display device including a plasma display panel (hereinafter referred to as “PDP” for convenience of explanation) and a fluorescent display tube (hereinafter referred to as “VFD” for convenience of explanation). .

  PDP has been widely used as a large flat screen display, realized as a large television receiver. This PDP is a mechanism in which a pair of glass plates are arranged opposite to each other with a small interval, and the periphery is sealed to provide a discharge space, and an image is projected by a phosphor that stimulates and emits light by ultraviolet rays generated by discharge. The glass plate on the side where the image is displayed is called the front plate, and the other glass plate is called the back plate. FIG. 1 exemplifies the structure of a front plate 1 and a back plate 2 of a general AC type PDP. A striped partition 16 is formed on the back plate 2, and the partition 16 is formed on the bottom of the recesses of these partitions 16. One electrode (address electrode) 13 is formed in parallel to the electrode substrate 10, and a dielectric layer (address protection layer) 15 covering the surface of the electrode 13 is provided on the glass substrate 10. Further, the wall surfaces of the partition walls 16 are coated with a phosphor 17 that is excited by ultraviolet rays. In order to increase the brightness of the PDP, the address protection layer 15 and the barrier ribs 16 are required to be white that reflects the light emitted from the phosphor 17. On the other hand, the front plate 1 is provided with a transparent electrode 11 formed of striped ITO or the like on a glass substrate 10 and a bus electrode 12 formed of one silver or the like provided on the transparent electrode, Further, a transparent dielectric film made of glass or the like is formed so as to cover the bus electrode 12, and an MgO film 14 is formed by vapor deposition so as to cover the dielectric film. Here, as a method for forming the PDP, an existing thick film technique is used for forming an electrode formed of silver, a dielectric, a partition, and the like.

  As shown in FIG. 2, a general VFD has a vacuum vessel composed of a face glass 21 and a glass substrate 22, and electrons emitted from a filament 26 in the vacuum vessel are lattice electrodes 23. In this structure, the fluorescent material on the segment electrode 24 is caused to collide with the segment electrode 24 to stimulate light emission to display characters, symbols, etc., and the segment electrode 24 serving as a display portion is formed on the glass substrate 22. Further, an insulating layer 25 is provided to insulate between the segment electrode 24 and the wiring 27 for transmitting a signal to the electrode. Here, the segment electrode 24 is often formed of a thick film silver paste, an insulator covering the segment electrode 24 is formed of a dielectric paste, and the segment electrode 24 is formed of a thick film paste mainly composed of graphite. In order to ensure electrical connection between the segment electrode 24 and the wiring 27, the insulating layer 25 is printed so as to form a through hole. 28 is a terminal.

  Since the PDP uses high strain point glass (PD-200 manufactured by Asahi Glass) or soda lime glass for the substrate, the firing temperature is about 600 ° C. at most. This is because a dense fired film cannot be obtained unless the softening point of the glass is lower than this temperature. Therefore, the conventional glass has realized this softening point by containing lead which is a harmful substance (see Patent Document 1). However, lead contained in glass is released into the global environment as waste when manufacturing display devices, as well as when disposing display devices, causing environmental problems such as pollution of soil, groundwater, rivers, and pollution. There are difficulties.

On the other hand, since B-Si-Zn-based glass has a characteristic that the relative dielectric constant can be made lower than that of lead glass, it is expected that the power consumption of PDP or the like can be reduced. However, when the address protective layer is formed of B-Si-Zn glass, it reacts with the address electrode of the silver electrode during firing and turns yellow, so that the additive that suppresses discoloration with the silver electrode during firing is added. B-Si-Zn glass to which (a copper compound or the like) is added has been proposed (see Patent Document 2, Patent Document 3, Patent Document 4, and Patent Document 5). However, additives that suppress discoloration color the glass, making it impossible to achieve a white address protection layer. Specifically, for example, glass containing copper exhibits a blue color. For this reason, an address protective layer material using bismuth-based glass that does not cause discoloration due to a silver electrode during firing has been proposed (see Patent Documents 6 and 7). However, since the dielectric constant of bismuth-based glass is not different from that of lead glass, a reduction in power consumption of a display device such as a PDP cannot be expected as a result.
JP 2001-52621 A JP 2004-35297 A JP 2005-320227 A JP 2006-117440 A JP 2006-232620 A JP 2002-53342 A JP-A-2005-231923

  The present invention has been made in view of the actual state of the prior art described above. It is a glass containing no lead, and a dense fired film can be obtained on soda lime glass. An object of the present invention is to provide a dielectric composition, a dielectric and a dielectric paste capable of realizing a relative dielectric constant.

  The dielectric composition according to the present invention comprises 70 to 95% by mass of glass powder A and at least one inorganic oxide powder B5 to 30 among quartz, alumina, zirconia, zircon, forsterite, titanium oxide, and heat-resistant black pigment. A dielectric composition containing mass%, wherein the glass powder A contains 70 to 95 mass% of the first glass powder containing bismuth without containing lead and alkali, and the second glass powder containing no bismuth and lead. 5-30 mass% is mixed, It is characterized by the above-mentioned.

Further, in the dielectric composition according to the present invention, the first glass powder does not contain lead and alkali, and Bi ₂ O ₃ 60 to 90% by mass, SiO ₂ 1 to 15% by mass, Al ₂ O in terms of oxides _{3 to} 15% by mass, _{2 to} 15% by mass of B ₂ O ₃ , and the second glass powder is 5 to 35% by mass of SiO _2, 1 to 7% by mass of Al ₂ O ₃ , and B ₂ O ₃ 15. It contains 1 to 15% by mass in total of alkali metal oxides selected from at least one of ˜45% by mass, ZnO 20 to 45% by mass, Li ₂ O, Na ₂ O, and K ₂ O. It is a feature.

  The dielectric according to the present invention is formed using any one of the above-described dielectric compositions, and the dielectric paste according to the present invention further includes the dielectric composition described above. The resin composition is characterized by containing 0.5 to 10 parts by mass of a resin and 20 to 45 parts by mass of an organic solvent with respect to 100 parts by mass of the powder of any one of the dielectric compositions.

  Since the dielectric composition, the dielectric, and the dielectric paste of the present invention do not contain lead in glass, lead is not released during the manufacturing process or disposal of the display device. For this reason, it does not cause environmental problems such as pollution of soil, groundwater, rivers, and pollution. In addition, the present invention can realize a low dielectric constant and suppress the color development with the silver electrode by the glass powder A formed by mixing the first glass containing bismuth and the second glass not containing lead and bismuth. Is possible. Further, by combining the mixed glass powder A and the inorganic oxide powder B, it is possible to suppress warping of the substrate due to firing, and to ensure the dimensional accuracy of the display device, which has a great effect on improving the accuracy of the display device.

  The dielectric composition of the present invention is a glass powder obtained by mixing 70 to 95% by mass of the first glass powder not containing lead and alkali and containing bismuth and 5 to 30% by mass of the second glass powder not containing lead and bismuth. A is specified. In this way, the mixing ratio is specified because when the second glass powder exceeds 30% by mass, the dielectric is discolored yellow by the silver electrode during firing, while the second glass powder This is because if the powder is less than 5% by mass, a decrease in the dielectric constant of the dielectric cannot be expected. More desirably, the glass powder A is composed of 70 to 90% by mass of the first glass powder and 10 to 30% by mass of the second glass powder. Note that it is not preferable to form the dielectric with only the second glass powder because discoloration of the silver electrode occurs. Moreover, the discoloration and relative dielectric constant of the silver electrode are caused by the composition of each glass.

  Next, in the dielectric composition of the present invention, the inorganic oxide powder B is added to suppress warpage of the substrate, and the content of the inorganic oxide powder B with respect to the glass powder A is 5 to 30% by mass. The reason is that if the amount is less than 5% by mass, the warp of the substrate due to firing cannot be suppressed, and if it exceeds 30% by mass, a dense dielectric cannot be formed. More desirably, it is in the range of 5 to 25% by mass. The inorganic oxide powder B is selected from quartz, alumina, zirconia, zircon, forsterite, titanium oxide, and heat-resistant black pigment.

Here, the reason why the glass powder A and the inorganic oxide powder B are combined will be described.
In recent years, display devices such as PDP have been multi-sided with a single large substrate in order to improve productivity and the like. The display device has been improved from high image quality to high definition, and if the substrate is warped by forming (firing) the dielectric, the dimensional accuracy of the display device cannot be secured, and as a result High image quality cannot be ensured. For this reason, it is necessary to suppress the warpage of the substrate as much as possible. In the present invention, even if the dielectric is composed of the first glass powder and the inorganic oxide powder B, the substrate does not warp. However, when glass powder A formed by mixing the first glass powder and the second glass powder is used, the substrate is warped and deformed by firing. This is due to the expansion and contraction of the glass due to firing and subsequent cooling. In other words, the glass powder and the substrate are heated to a temperature of 500 ° C. or higher by firing, and thermally expand. However, when the temperature is lowered to room temperature, the sintered glass powder and substrate contract by the thermal expansion coefficient, and the substrate contracts. If the shrinkage of the sintered glass is larger than that, the substrate warps.

Usually, a dielectric material (in the present invention, the first glass powder and the second glass) from room temperature to the glass transition point (450 ° C. to 500 ° C. in the first glass powder and the second glass powder of the present invention, although depending on the glass) The thermal expansion coefficient of the powder is designed to follow the thermal expansion coefficient of a soda lime glass substrate (glass transition point 550 to 650 ° C., thermal expansion coefficient 85 × 10 ⁻⁷ from room temperature to 400 ° C.). However, generally, at a temperature higher than the glass transition point, the coefficient of thermal expansion of glass shows a value that is almost an order of magnitude higher than that at a low temperature. Depending on the temperature, the thermal expansion coefficient of the first glass powder and the second glass powder is nearly one digit greater than that of the soda lime glass substrate. Furthermore, when the thermal expansion coefficients of the glass containing lead or the first glass powder containing bismuth and the second glass powder are higher than the glass transition point, the second glass powder has a larger value. is there. Therefore, if the second glass powder is included, warping of the substrate becomes a problem. Therefore, it is only necessary to control the thermal expansion coefficient of the glass powder in order to suppress the warpage of the substrate, and for that purpose, the thermal expansion coefficient of the second glass powder is adjusted to a value that does not cause the warpage of the substrate. I can deal with it. The coefficient of thermal expansion is determined by the glass composition. However, when the second glass powder has a composition having such a thermal expansion coefficient, it is difficult to design a glass that can be fired at a firing temperature of 600 ° C. or lower.

  Therefore, in the present invention, the inorganic oxide powder B is added as a means for controlling the warpage of the substrate without changing the glass composition. This is because the inorganic oxide powder B becomes an aggregate and the second glass powder is prevented from excessive thermal expansion, so that the shrinkage is optimized and the warpage of the substrate is suppressed as a result. Furthermore, the mechanical strength is improved by adding the inorganic oxide powder B, and as a result, the withstand voltage characteristic is improved. The reason is that most dielectric breakdowns are triggered by mechanical breakdown when a potential is applied.

  In the firing process of the glass powder, bubbles (voids) are likely to be generated when fired at a temperature higher than the temperature at which a dense fired film is formed (fired excessively). The generation of voids is thought to be due to a decrease in viscosity due to glass melting. The addition of the inorganic oxide powder B inhibits the sintering of the glass powder during the firing process, and has the effect of suppressing the generation of voids such as bubbles even when the glass powder is excessively fired. However, the temperature range in which the glass powder can be fired without generating voids is narrow. As described above, the PDP is multi-chamfered, and the firing furnace is wide as long as the width of the display device to be fired. It is difficult to make the temperature in the furnace uniform, and a temperature distribution occurs. When a display device is fired in such a firing furnace with a material in the optimum region of the firing temperature that is only a pinpoint, a part that is excessively fired or a part that is insufficiently fired is generated. As a result, the fired film is excessively fired. A part with many voids due to and a part with many voids due to insufficient firing occur, and a dense fired film as a whole cannot be obtained. A dielectric material that can be densely fired and can take a wide temperature range where no voids are generated is also suitable for improving the productivity of a display device.

By combining the glass powder A and the inorganic oxide powder B, the thermal expansion coefficient from room temperature to around 400 ° C. can be controlled. Since quartz glass of quartz is lower than glass powder A, the thermal expansion coefficient of the dielectric can be lowered.
The warpage of the substrate is not affected by the thermal expansion coefficient of the inorganic oxide powder B. The reason is that, as described above, the warpage of the substrate depends on the thermal expansion coefficient at a temperature higher than the glass transition point of the second glass powder, and the thermal expansion coefficient at this temperature is supplemented by the thermal expansion coefficient of the inorganic oxide powder B. Because it is difficult. Specifically, when the quartz glass (55 × 10 ⁻⁷ / ° C.) is selected for the inorganic oxide powder B and the alumina (80 × 10 ⁻⁷ / ° C.) is selected, the warpage of the substrate does not change.

  Quartz and forsterite are known to have a low dielectric constant, and the addition of these has the effect of improving these characteristics and lowering the dielectric constant. Quartz is known to undergo phase transition, and when it undergoes phase transition to cristobalite or the like, the thermal expansion coefficient changes abruptly. A change in the thermal expansion coefficient may cause cracks in the dielectric. In order to prevent such a situation, quartz glass powder can be used. Even if quartz glass powder is used, it has the same effect as the inorganic oxide powder B of the present invention.

  The inorganic oxide powder B is not limited to selection of only one type, and a plurality of types can be combined. When it is desired to make the dielectric white, only titanium oxide can be added, or other inorganic oxides and titanium oxide can be added in combination. As the titanium oxide, crystal systems such as anatase and rutile are known, and any of them can be used.

  As the heat-resistant pigment, black pigments such as Fe—Co—Cr, Cu—Cr—Mn composite oxide, Ni—Mn—Fe—Co composite oxide, and Fe—Mn composite oxide can be used.

The particle size D ₅₀ of the inorganic oxide powder B is desirably 10 μm, and more desirably 5 μm or less. When the particle size exceeds 10 μm, a dense dielectric cannot be obtained. For confirmation of the particle size, a known particle size analyzer (for example, “Microtrack” registered trademark) can be used. D ₅₀ is the median value of the particle size in the cumulative particle size distribution.

Next, the components of the glass powder of the present invention and the reasons for limiting the content thereof will be described.
The first glass powder does not contain lead and alkali, and Bi ₂ O ₃ 60 to 95% by mass, SiO ₂ 1 to 15% by mass, B ₂ O ₃ 2 to 15% by mass, Al ₂ O ₃ 1 to 1% in terms of oxides. Although it consists of 15 mass%, when this 1st glass powder contains an alkali, since it discolors yellow with a silver electrode by baking, it shall be the thing which does not contain an alkali.

Bi ₂ O ₃ in the first glass powder is a component that lowers the softening point of glass, but if it is less than 60% by mass, the softening point of glass cannot be made 600 ° C. or lower, and the relative dielectric constant of glass. On the other hand, when it exceeds 90% by mass, the relative dielectric separation becomes high, and even if it has the second glass powder, it cannot be controlled, so it is limited to 60 to 90% by mass. More desirably, it is 60 to 85% by mass.

SiO ₂ is an essential network former of glass, but if it contains more than 15% by mass of the first glass powder, the glass is easily crystallized, and a firing furnace in which the above temperature distribution is generated is used. In addition, the crystal precipitation is biased and a homogeneous dielectric cannot be formed. On the other hand, if it is less than 1% by mass, the water resistance and chemical resistance of the glass cannot be ensured. And limited. More desirably, the content is 1 to 12% by mass.

Al ₂ O ₃ has an effect of preventing phase separation of the glass, but the effect cannot be expected if it is less than 1% by mass in the first glass powder. On the other hand, if it exceeds 15% by mass, the softening point of the glass is increased, Since it cannot endure practical use, it was limited to 1 to 15% by mass.

B ₂ O ₃ in the glass is an essential component, and has the effect of lowering the softening point and increasing the fluidity to stabilize the glass, but if the first glass powder is less than 2% by mass, the fluidity of the glass is ensured. On the other hand, if it exceeds 15% by mass, the glass transition point becomes less than 440 ° C., which may cause a problem in the sealing process of the display device.

Note that ZrO ₂ , ZnO, or an alkaline earth oxide (BaO, CaO, SrO, or the like) can be appropriately added to the first glass powder. ZrO ₂ leads to improvement of water resistance and chemical resistance of glass. In particular, since the PDP undergoes a photolithography process to form the barrier ribs, it is necessary to withstand the photoresist developer, the stripping solution and the water used for cleaning, and the addition of ZrO ₂ is beneficial, but the addition amount is Considering vitrification, it is preferably 10% by mass or less. ZnO has the effect of lowering the softening point and appropriately adjusting the thermal expansion coefficient, but its content is preferably 30% by mass or less in view of vitrification.

The second glass powder _SiO 2 5 to 35 _wt%, Al ₂ O 3 1 to 7 _{wt%, B} 2 O 3 15 to 45 wt%, ZnO 20 to 45 _wt%, Li 2 O, _Na 2 O 1 to 15% by mass of an alkali metal oxide selected from one or more kinds of K ₂ O, but the second glass powder does not contain bismuth to keep the relative dielectric constant of the second glass powder low. Because.

SiO ₂ is an essential network former of glass. However, when the content of the second glass powder exceeds 35% by mass, the softening point of the glass is increased, whereas when it is less than 5% by mass, the water resistance of the glass is increased. And chemical resistance cannot be ensured, so it is limited to 5 to 35% by mass.

Al ₂ O ₃ has the effect of preventing the phase separation of the glass as in the case of the first glass powder, but the effect cannot be expected if it is less than 1% by mass in the second glass powder, and on the other hand, 7% by mass When it exceeds, the softening point of glass will be raised and it will not endure practical use, Therefore It limited to 1-7 mass%.

B ₂ O ₃ in the glass is an essential component and has the effect of lowering the softening point and increasing the fluidity to stabilize the glass. However, if the B ₂ O ₃ is less than 15% by mass in the second glass powder, the glass On the other hand, if it exceeds 45% by mass, the glass transition point will be less than 440 ° C., and the dielectric may be softened in the sealing process of the display device, resulting in problems such as inability to ensure dimensional accuracy. Therefore, it is limited to 15 to 45% by mass.

  ZnO has the effect of lowering the softening point and appropriately adjusting the thermal expansion coefficient, but if the ZnO content in the second glass powder is less than 20% by mass, the desired softening point cannot be achieved, while if it exceeds 45% by mass. In the glass composition of the present invention, vitrification is difficult, and the fired film cannot be densified, so it is limited to 20 to 45% by mass. More desirably, it is 28 to 40% by mass.

Alkali metal oxide R ₂ O (an oxide selected from at least one of K ₂ O, Na ₂ O, and Li ₂ O) has the effect of lowering the softening point and increasing the fluidity, and thermal expansion. Although there is an effect of increasing the coefficient, if the total content of these alkali metal oxides in the second glass powder is less than 1% by mass, the softening point becomes too high to obtain a desired value, If it exceeds 15% by mass, the coefficient of thermal expansion increases, making it unsuitable for using soda lime glass or the like as a substrate, and if the coefficient of thermal expansion increases, it leads to cracks in the partition walls and dielectrics. It was limited to mass%. More desirably, it is 2 to 15% by mass.

ZrO ₂ is not an essential component of the glass composition as described above, but can be added as appropriate to the second glass powder because it has the effect of improving water resistance and chemical resistance. However, when the addition amount exceeds 10% by mass, the softening point of the glass is raised, and a desired value cannot be realized.

  On the other hand, glass alkaline earth oxides RO (BaO, SrO, CaO) have the effect of lowering the softening point of the glass and increasing the fluidity and appropriately adjusting the thermal expansion coefficient. An expansion coefficient becomes large and it becomes unsuitable for using soda-lime glass for a board | substrate.

Similar to the inorganic oxide powder B described above, the particle size of the first and second glass powders described above is preferably 10 μm or less at D ₅₀ and more preferably 5 μm or less. If it is larger than this, it will not be possible to obtain dense barrier ribs and dielectrics. A powder having a desired particle size can be obtained by a known pulverization method such as a ball mill or a jet mill. The particle size of the glass powder can be confirmed using the same known particle size analyzer as described above (for example, “Microtrack” registered trademark).

The dielectric composition according to the present invention comprises 70 to 95% by mass of glass powder A and at least one inorganic oxide powder B5 to 30 among quartz, alumina, zirconia, zircon, forsterite, titanium oxide, and heat-resistant black pigment. A dielectric composition containing mass%, wherein the glass powder A contains 70 to 95 mass% of the first glass powder containing bismuth without containing lead and alkali, and the second glass powder containing no bismuth and lead. A dielectric composition obtained by mixing 5 to 30% by mass, or the first glass powder in this dielectric composition does not contain lead and alkali, and Bi ₂ O ₃ 60 to 90% by mass in terms of oxide, SiO ₂ 15 _{wt%, Al} 2 O 3 1 to 15 _{wt%, B} 2 O 3 containing 2 to 15 wt%, the second glass powder _SiO 2 5 to 35 wt%, _Al 2 _{O 3} To 7 _{wt%, B} 2 O 3 _15~45 wt%, ZnO 20 to 45 _{wt%, Li 2 O, Na 2} O, in a total amount of alkali metal oxide selected from at least one or more of _{K 2} O The dielectric composition containing 1 to 15% by mass is formed using a dielectric paste of the present invention by applying the dielectric paste of the present invention to a substrate by screen printing or the like, and applying and printing the paste solvent A method of forming through a drying step of removing the dielectric, a baking step of sintering the dielectric composition, or a method of firing the dielectric composition powder on a substrate without using a dielectric paste Can do.

  Here, in the dielectric paste of the present invention composed of the dielectric composition powder, a resin and an organic solvent, the resin which is one of the components retains the viscosity of the paste, and after coating and drying. Is necessary for maintaining the shape of the film and improving the mechanical strength of the dry film, but the mechanical strength of the dry film is insufficient if it is less than 0.5 parts by mass with respect to 100 parts by mass of the dielectric composition powder (glass paste inorganic component). On the other hand, there is a problem that the viscosity of the dielectric paste cannot be ensured and the inorganic component during storage settles and does not form a paste. On the other hand, when the amount exceeds 10 parts by mass, the viscosity of the dielectric paste is not suitable for screen printing. In order to become a suitable high viscosity, it limited to 0.5-10 mass parts. More desirably, the content is 1% by mass to 8% by mass. As this resin, an ethyl cellulose resin, an acrylic resin, or a polyvinyl butyral resin used in a known thick film technique can be used. The acrylic resin includes a methacrylate resin. There is no problem as long as the molecular weight of the resin is within a range in which the viscosity of the glass paste can be secured by dissolving in an organic solvent described later. For example, there is no problem if the molecular weight of the resin is in the range of 5000 to 200000.

  In addition, the organic solvent is an essential component for improving the fluidity of the paste. However, when the amount of the solvent is less than 20% by mass with respect to 100% by mass of the dielectric composition powder (glass paste inorganic component), the paste should be made into a paste. On the other hand, if it exceeds 45% by mass, the shrinkage of the film during drying becomes large and cracks of the dry film are likely to occur, so it is limited to 20 to 45% by mass. The organic solvents are terpinol, dihydroterpinol, butyl carbitol acetate, butyl carbitol, 2,2,4-trimethyl-1,3-pentanediol monobutyrate, octyl alcohol used in known thick film technology. You can choose from. Of course, it goes without saying that these solvents can be used alone or in combination.

  Paste printing (coating) can be performed with a die coater or a roll coater as well as screen printing. Known additives can be added to the glass paste as thick film glass pastes such as antifoaming agents, dispersants, and photosensitive materials. The glass paste can be produced by a known method such as a roll mill or a ball mill.

  Examples of the present invention and comparative examples are shown below, but the present invention is not limited to these examples.

The glass in this example was obtained by melting, quenching at 1300 ° C., and pulverizing with a ball mill. The particle size of the obtained glass powder was measured with a microtrack, and the glass transition point and the softening point were measured with TG-DTA (TG / DTA320 type manufactured by Seiko Denshi). The coefficient of thermal expansion was measured with TMA (TMA320 manufactured by Seiko Electronics Co., Ltd.) for glass in a rod shape.
Next, 35 parts by mass of a vehicle was added to 100 parts by mass of an inorganic component of glass paste in which glass powder and inorganic oxide were blended in the composition shown in Table 2, and the mixture was mixed by a roll mill to obtain a glass paste. Alumina having a particle size D ₅₀ (0.5 μm), quartz glass having a particle size D ₅₀ (2 μm), and titanium oxide having a rutile type and a particle size D ₅₀ (0.5 μm) were used. As the vehicle, a resin obtained by mixing 10% by mass of ethyl cellulose (molecular weight 160000) with a resin, 50% by mass of terpinol and 40% by mass of butyl carbitol acetate and heating to 60 ° C. was used.

  Each of the dielectric pastes shown in Table 2 thus obtained was applied and printed on a soda lime glass substrate, and the solvent of the applied and printed paste was removed in a drying step, followed by firing at a predetermined temperature in a belt-type firing furnace ( Peak temperature holding time 30 minutes).

Table 3 shows the state (denseness) of the fired film, the discoloration of the silver electrode, the warpage of the substrate, and the relative dielectric constant in this example.
Here, the state of the fired film is that the obtained paste is printed on a soda lime glass substrate, the solvent of the coated and printed paste is removed in the drying step, and then fired in a belt-type firing furnace having a peak temperature holding time of 30 minutes. The result of having confirmed the presence or absence of a void by observing the baking cross section of the dielectric after baking by SEM is shown. In addition, the discoloration of the silver electrode is obtained by printing the paste on a soda lime glass substrate on which the silver electrode is formed by the thick film method and firing it in a belt-type firing furnace having a peak temperature of 580 ° C. and a holding time of 30 minutes. The result of having confirmed visually is shown. The warp of the substrate is a belt type printed on a 5 cm square soda lime glass substrate having a thickness of 0.7 mm, and having a peak temperature of 580 ° C. and a holding time of 30 minutes. The result of having traced and confirmed the back surface of the board | substrate when baking with a baking furnace with the surface roughness meter (Tokyo Seimitsu E-MD-S39A type | mold) is shown. If the substrate warpage is 50 μm or less, it is practically usable. Further, the relative dielectric constant is the diameter of the dielectric composition powder obtained by mixing, in a mortar, a powder having a composition with no problem in discoloration of the silver electrode and denseness of the fired film among the paste inorganic components listed in Table 2. It is formed into a tablet with a height of 7 mm and a height of 2 mm, fired in a box-type firing furnace at a temperature of 580 ° C. and a holding time of 30 minutes, and cooled to room temperature, having a diameter of 6 mm and a height of about 1.5 mm. The surface of a tablet-like sample is polished, gold is vapor-deposited on both bottom surfaces (when the tablet is compared to a cylinder), and the capacitance measured by the Q meter method using a cylindrical capacitor with both gold-deposited bottom surfaces as electrodes. Indicates the calculated value. The capacitance was measured using a capacitance meter (Yokogawa Hewlett Packard model 4278A). A relative dielectric constant of 15 or less is a practically low value.

  As is apparent from the results in Table 3, the pastes 1 to 8 of the present invention have a temperature region that can be densely fired, are not discolored by the silver electrode, and all the warpage of the substrate is 50 μm or less that can withstand practical use. The dielectric constants are all as low as 15 or less. On the other hand, in the pastes 9, 10, and 13 of the comparative example, the content of the second glass powder satisfies the range of the present invention (5 to 30% by mass) with the paste 9 being 4% by mass and the pastes 10 and 13 being zero. Therefore, the relative dielectric constant exceeds the practical value of 15, and a low relative dielectric constant cannot be realized. Moreover, since the content of the 1st glass powder has remove | deviated from the range (70-95 mass%) of this invention, discoloration has arisen in the silver electrode of the paste 11 of a comparative example. Furthermore, in the paste 12 of the comparative example, the inorganic oxide powder B is added beyond the range of the present invention (5 to 30% by mass), and there is no temperature range in which the paste can be densely fired. Furthermore, since the pastes 14 and 15 of the comparative examples do not contain the inorganic oxide powder B, the warp of the substrate greatly exceeds 50 μm and is not practical.

  Since the dielectric composition, the dielectric, and the dielectric paste of the present invention do not contain lead in glass, lead is not released during the manufacturing process or disposal of the display device. For this reason, it does not cause environmental problems such as pollution of soil, groundwater, rivers, and pollution. In addition, the present invention can realize a low dielectric constant and suppress color development with a silver electrode by using glass powder obtained by mixing glass containing bismuth and glass not containing lead and bismuth. Further, by combining the mixed glass powder and the inorganic oxide powder, it is possible to suppress warping of the substrate due to baking, and to ensure the dimensional accuracy of the display device, which has a great effect on improving the accuracy of the display device. Needless to say, the barrier rib glass paste of the present invention is not limited to the barrier rib glass paste of PDP, but can be applied to barrier rib formation of display devices such as fluorescent display tubes and field emission displays.

BRIEF DESCRIPTION OF THE DRAWINGS It is a figure which shows an example of the general AC type PDP which concerns on this invention, A figure (a) is a perspective view which partially fractures | ruptures and shows the structure of the front plate of AC type PDP, A figure (b) is also AC type PDP. It is a perspective view which shows a partially broken structure of the back plate. It is a perspective view which shows an example of general VFD concerning the present invention partially fractured.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Front plate 2 Back plate 10 Glass substrate 11 Transparent electrode 12 Bus electrode 13 Address electrode 14 MgO film 15 Dielectric layer 16 Partition 17 Phosphor 21 Face glass 22 Glass substrate 23 Grid electrode 24 Segment electrode 25 Insulating layer 26 Filament 27 Wiring 28 Terminal

Claims (4)

  A dielectric composition containing 70 to 95% by mass of glass powder A and 5 to 30% by mass of inorganic oxide powder B of at least one of quartz, alumina, zirconia, zircon, forsterite, titanium oxide and heat-resistant black pigment. The glass powder A is obtained by mixing 70 to 95% by mass of the first glass powder containing bismuth without containing lead and alkali and 5 to 30% by mass of the second glass powder not containing lead and bismuth. A dielectric composition characterized by the above. _Bi 2 _O 3 60 to _90% by mass in terms of oxide of the first glass powder is free of lead and _alkali, SiO 2 1 to 15 _{wt%, Al} 2 O 3 1~15 _wt%, B _{2 O} 3 ₂ containing 15 wt%, the second glass powder _SiO 2 5 to 35 _wt%, Al ₂ O 3 1 to 7 _{wt%, B} 2 O 3 15 to 45 wt%, ZnO 20 to 45 wt%, _2. The dielectric composition according to claim 1, comprising a total of 1 to 15% by mass of an alkali metal oxide selected from at least one of Li ₂ O, Na ₂ O, and K ₂ O. object.   A dielectric comprising the dielectric composition according to claim 1 or 2.   A dielectric paste formed of 0.5 to 10 parts by mass of a resin and 20 to 45 parts by mass of an organic solvent with respect to 100 parts by mass of the powder of the dielectric composition according to claim 1 or 2.

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