Transient voltage protection component

Abstract

This transient voltage protection member has a pair of discharge electrodes facing each other with a gap therebetween, and a discharge inducing part in contact with the pair of discharge electrodes. The discharge electrode includes pores having an average diameter of 0.45 [mu] m or more and 2.04 [mu] m or less.

Description

Technical Field

[0001] The present disclosure relates to a transient voltage protection component. Background Art

[0002] In recent years, with the advancement of miniaturization and higher performance in electronic devices, electronic components used to protect circuits from transient voltages such as ESD (electrostatic discharge) have attracted considerable attention. For example, Patent Document 1 discloses a transient voltage protection component (so-called ESD suppressor) comprising a pair of opposing discharge electrodes and a discharge inducing portion adjacent to the discharge electrodes. Compared to other ESD protection components such as multilayer varistors and Zener diodes, the transient voltage protection component disclosed in Patent Document 1 can reduce electrostatic capacitance, making it suitable for circuits in high-speed transmission systems and high-frequency circuits.

[0003] However, demands for higher transmission speeds and lower driving voltages in electronic devices are increasing, and the transient voltage protection component disclosed in Patent Document 1 is required to maintain a low discharge inception voltage and improve ESD tolerance.

[0004] Prior art literature

[0005] Patent Literature

[0006] Patent Document 1: WO2009 / 098944 Summary of the Invention

[0007] Problems to be solved by the invention

[0008] An object of exemplary embodiments of the present disclosure is to provide a transient voltage protection component that maintains a low discharge inception voltage and improves ESD tolerance.

[0009] Technical solutions to solve problems

[0010] In order to achieve the above-mentioned object, the transient voltage protection component of the first aspect of the present disclosure has:

[0011] A pair of discharge electrodes facing each other with a gap therebetween, and

[0012] a discharge inducing portion connected to the pair of discharge electrodes,

[0013] The discharge electrode includes pores having an average diameter of 0.45 μm or more and 2.04 μm or less.

[0014] The transient voltage protection component according to the first aspect, by having the above-mentioned features, can maintain a low discharge start voltage and improve ESD tolerance.

[0015] Preferably, the area ratio of the pores in the cross section of the discharge electrode is 1.0% or more and 12.4% or less.

[0016] Preferably, the discharge induction portion includes a base material made of glass, and metal particles and ceramic particles dispersed in the base material.

[0017] Preferably, the discharge electrode further includes ceramic particles having an average diameter of 0.05 μm or more and 0.54 μm or less.

[0018] Preferably, the discharge electrode contains at least one of Pd, Ag, and Pt as a main component.

[0019] A transient voltage protection component according to a second aspect of the present disclosure includes: a pair of discharge electrodes facing each other with a gap therebetween; and a discharge induction portion in contact with the pair of discharge electrodes.

[0020] The discharge electrode includes ceramic particles having an average diameter of 0.05 μm or more and 0.54 μm or less.

[0021] The transient voltage protection component according to the second aspect has the above-mentioned features, and similarly to the first aspect, can maintain a low discharge start voltage and improve ESD tolerance.

[0022] Preferably, the area ratio of the ceramic particles in the cross section of the discharge electrode is 0.4% or more and 5.1% or less.

[0023] Preferably, the ceramic particles contain SiO2 as a main component.

[0024] Preferably, the discharge induction portion includes a base material made of glass, and metal particles and ceramic particles dispersed in the base material.

[0025] Preferably, the discharge electrode further includes pores having an average diameter of 0.45 μm or more and 2.04 μm or less.

[0026] Preferably, the discharge electrode contains at least one of Pd, Ag, and Pt as a main component. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 This is a perspective view showing a transient voltage protection component according to one embodiment of the present invention.

[0028] Figure 2A It is along Figure 1 A cross-sectional view taken along line IIA-IIA is shown.

[0029] Figure 2B It is along Figure 1 A cross-sectional view taken along line IIB-IIB is shown.

[0030] Figure 3A This is an example of a schematic diagram showing a cross section of a discharge electrode.

[0031] Figure 3B This is another example of a schematic diagram showing a cross section of a discharge electrode.

[0032] Figure 3C This is another example of a schematic diagram showing a cross section of a discharge electrode.

[0033] Figure 4A It is a schematic diagram showing a cross section of a discharge induction portion.

[0034] Figure 4B This is a schematic diagram showing a method for measuring the closest inter-particle distance of metal particles in a discharge induction portion.

[0035] Figure 5 This is a top view of a green sheet used in the manufacturing process of transient voltage protection components.

[0036] Figure 6 This is an exploded perspective view of a green chip used in the manufacturing process of a transient voltage protection component.

[0037] Figure 7A It is a cross-sectional view showing a modified example of the transient voltage protection component.

[0038] Figure 7B It is a cross-sectional view showing a modified example of the transient voltage protection component. DETAILED DESCRIPTION

[0039] The following describes embodiments of the present disclosure with reference to the accompanying drawings. The embodiments of the present disclosure described below are examples for illustrating the present disclosure. The various components of the embodiments, such as numerical values, shapes, materials, and manufacturing processes, can be changed or altered within the scope that does not cause technical problems. In addition, the shapes and dimensions shown in the drawings of the present disclosure may not necessarily be consistent with the actual shapes and dimensions. This is because the shapes and dimensions in the drawings are sometimes changed for illustration purposes.

[0040] First embodiment

[0041] like Figure 1 As shown, the transient voltage protection component 2 of this embodiment includes an element body 10 having a hexahedral shape (rectangular parallelepiped shape) and a pair of external electrodes (a first external electrode 6 and a second external electrode 8 ) formed on the outer surface of the element body 10 .

[0042] The element body 10 has a pair of end faces 10a approximately perpendicular to the X-axis, a pair of side faces 10b approximately perpendicular to the Y-axis, and a pair of main faces 10c approximately perpendicular to the Z-axis. The dimensions of the element body 10 are not particularly limited and can be appropriately sized depending on the intended use. In the drawings, the X-axis, Y-axis, and Z-axis are approximately perpendicular to one another.

[0043] The first external electrode 6 covers one end surface 10a and is formed so as to extend from the end surface 10a to a portion of the side surface 10b and the main surface 10c. The second external electrode 8 covers the other end surface 10a and is formed so as to extend from the end surface 10a to a portion of the side surface 10b and the main surface 10c. The first external electrode 6 and the second external electrode 8 are insulated from each other so as not to contact each other in the X-axis direction.

[0044] Figure 2A The XZ cross section of the transient voltage protection component 2 is cut approximately in the center of the Y axis direction. Figure 2B The XY cross section of the transient voltage protection component 2 is cut approximately in the center of the Z axis direction. Figure 2A and Figure 2B As shown, the element body 10 includes a plurality of insulating layers 11 , a pair of discharge electrodes 20 , a discharge inducing portion 30 , and a cavity 15 .

[0045] The multiple insulator layers 11 are each sintered bodies having electrical insulation properties and are stacked along the Z-axis. The insulator layers 11 are integrated to such an extent that the boundaries between the layers are indistinguishable. The thickness and number of insulator layers 11 stacked are not particularly limited and can be appropriately determined based on the dimensions of the element body 10.

[0046] Of the pair of discharge electrodes 20, the discharge electrode electrically connected to the first external electrode 6 is referred to as the "first discharge electrode 21," and the other discharge electrode electrically connected to the second external electrode 8 is referred to as the "second discharge electrode 22." In the following description, when "discharge electrode 20" is used as a general term, it is intended to describe features common to both the first discharge electrode 21 and the second discharge electrode 22.

[0047] Each discharge electrode 20 is an electrode layer having a long rectangular shape in plan view, and is interposed between predetermined insulating layers 11. The average thickness T of each discharge electrode 20 is DE The thickness is not particularly limited, and can be, for example, 2 μm to 20 μm, preferably 3 μm to 10 μm. The first and second discharge electrodes 21 and 22 may have different average thicknesses, but preferably have the same average thickness.

[0048] Furthermore, the first discharge electrode 21 and the second discharge electrode 22 are both stacked on the same insulator layer 11. The distance from the main surface 10c to the first discharge electrode 21 in the Z-axis direction is approximately the same as the distance from the main surface 10c to the second discharge electrode 22 in the Z-axis direction. In other words, the first discharge electrode 21 and the second discharge electrode 22 are positioned at approximately the same height in the Z-axis direction. However, the first discharge electrode 21 and the second discharge electrode 22 are spaced apart from each other so as not to directly contact each other in the X-axis direction.

[0049] The first discharge electrode 21 includes a lead portion 21a and an opposing portion 21b. The lead portion 21a is the end portion of the first discharge electrode 21 facing outward in the X-axis direction. This lead portion 21a is exposed at the end surface 10a of the element body 10 and is electrically connected to the first external electrode 6. Meanwhile, the opposing portion 21b is the end portion of the first discharge electrode 21 facing inward in the X-axis direction. This opposing portion 21b is located inside the cavity 15 and faces the opposing portion 22b of the second discharge electrode 22.

[0050] The second discharge electrode 22 includes a lead portion 22a and an opposing portion 22b. The lead portion 22a is the end portion of the second discharge electrode 22 facing outward in the X-axis direction. This lead portion 22a is exposed at the end surface 10a of the element body 10 and is electrically connected to the second external electrode 8. Meanwhile, the opposing portion 22b is the end portion of the second discharge electrode 22 facing inward in the X-axis direction. This opposing portion 22b is located inside the cavity 15 and faces the opposing portion 21b of the first discharge electrode 21.

[0051] The facing portions 21b and 22b are separated in the X-axis direction, and a gap G is formed between the facing portions 21b and 22b. When a voltage exceeding a predetermined value is applied between the first external electrode 6 and the second external electrode 8, a discharge occurs across the gap G. The transient voltage protection component 2 prevents transient voltages from being applied to the device under protection (DUP) through this discharge between the facing portions 21b and 22b.

[0052] The width of the gap G in the X-axis direction is not particularly limited and can be appropriately determined to obtain the desired discharge characteristics. For example, the width of the gap G in the X-axis direction may be greater than or equal to 10 μm and less than or equal to 150 μm, preferably greater than or equal to 30 μm and less than or equal to 100 μm. In addition, the length L of the opposing portions of the discharge electrodes facing each other on the discharge induction unit 30 is G The length of each opposing portion (21b, 22b) in the Y-axis direction is not particularly limited, and may be, for example, 10 μm or more and 500 μm or less, preferably 30 μm or more and 200 μm or less. G The ratio of the width of the gap G in the X-axis direction (LG / G) may be, for example, 0.1 or more and 30 or less, and preferably 0.5 or more and 10 or less.

[0053] The discharge induction portion 30 is stacked below the Z-axis of the discharge electrodes 20 so as to be in contact with both discharge electrodes 20 in the stacking direction. In other words, the discharge induction portion 30 is formed across the first discharge electrode 21 and the second discharge electrode 22, connecting the opposing portion 21b and the opposing portion 22b. The discharge induction portion 30 has a generally rectangular shape when viewed from above, as viewed from the stacking direction. Furthermore, the width of the discharge induction portion 30 in the X-axis direction is preferably greater than the width of the gap G, and the width of the discharge induction portion 30 in the Y-axis direction is preferably greater than the width of the opposing portions (21b, 22b) in the Y-axis direction. The average thickness T of the discharge induction portion 30 is 1 / 4. AE The thickness is not particularly limited, but is preferably 1 μm to 15 μm, for example. The discharge induction portion 30 has a function of facilitating discharge between the first discharge electrode 21 and the second discharge electrode 22 .

[0054] The cavity 15 is a space formed by burning off the organic component (varnish) during the manufacturing process of the transient voltage protection component 2. Figure 2A As shown, the surfaces defining the cavity 15 include the surface near the facing portion 21b of the first discharge electrode 21, the surface near the facing portion 22b of the second discharge electrode 22, the surface of the discharge inducing portion 30, and the lower surface of the insulator layer 11 located above the discharge electrode 20. The shape and dimensions of the cavity 15 are not particularly limited; however, the cavity 15 is preferably formed so as to cover the facing portion of the discharge electrode 20 and the discharge inducing portion 30 when viewed in the stacking direction. This cavity 15 serves to absorb thermal expansion of the first discharge electrode 21, the second discharge electrode 22, the insulator layer 11 near the discharge electrode 20, and the discharge inducing portion 30 during discharge.

[0055] Next, features such as the material of each component will be described in detail.

[0056] The insulator layer 11 only needs to be composed of an inorganic compound having insulating properties, and the composition of the insulator layer 11 is not particularly limited. For example, the insulating layer 11 may also include one or more inorganic compounds selected from Fe2O3, NiO, copper oxide (CuO, Cu2O), ZnO, MgO, SiO2, TiO2, MnCO3, SrCO3, CaCO3, BaCO3, Al2O3, ZrO2, and B2O3. In particular, it is preferred that ZrO2 and / or copper oxide be included in the insulator layer 11. In the case of including two or more inorganic compounds, the inorganic compound may also exist as a composite compound (for example, CaZrO3, etc.). In addition, the insulator layer 11 may include glass together with the above-mentioned inorganic compounds, and may also include: a secondary component compound including rare earth elements, etc.

[0057] The discharge electrode 20 is a sintered layer of a conductive metal. Figure 3A As shown, the discharge electrode 20 of the present embodiment includes a metal conductor portion 25 and fine pores 26 dispersed discontinuously inside the metal conductor portion 25 .

[0058] The metal conductor 25 serves as the base material (matrix phase) of the discharge electrode 20 and contains a conductive metal as the main component of the discharge electrode 20. For example, the metal conductor 25 may contain Ag, Pd, Au, Pt, Cu, Ni, Al, Mo, W, or an alloy containing at least one of these metal elements (e.g., an Ag-Pd alloy). In particular, the metal conductor 25 preferably contains at least one of Pd, Ag, and Pt as its main component, and more preferably, at least one of Pd, Pt, and an Ag-Pd alloy. The content of the main component in the discharge electrode 20 may be 30 wt% or more, preferably 50 wt% or more, more preferably 80 wt% or more, and even more preferably 90 wt% or more.

[0059] The first discharge electrode 21 and the second discharge electrode 22 may have different main components, but preferably they are composed of the same main component. Furthermore, the discharge electrode 20 may contain trace amounts (e.g., 1 wt % or less) of non-metallic components such as S and P.

[0060] The pores 26 in the discharge electrode 20 have an average diameter d of 0.45 μm or more and 2.04 μm or less. P The average diameter d of the pores 26 P The thickness is preferably 0.60 μm or more and 1.60 μm or less, and more preferably 0.80 μm or more and 1.30 μm or less.

[0061] The average diameter d of the pores 26 PThe arithmetic mean of the equivalent circular diameters of the pores 26 in the cross section of the discharge electrode 20 can be calculated by observing the cross section of the discharge electrode 20 using a scanning electron microscope (SEM) or a scanning transmission electron microscope (STEM), and performing image analysis on the obtained cross-sectional photograph. Specifically, the area of ​​each pore 26 observed in the cross section is measured, and the equivalent circular diameter of each pore 26 is determined based on the area. In this analysis, the equivalent circular diameters of at least 100 pores 26 are determined, and the average diameter d is calculated. P In addition, in the captured TEM image and STEM image of the cross section of the discharge electrode 20 , the metal conductor portion 25 and the pores 26 can be identified based on the contrast.

[0062] Having the above average diameter d P The pores 26 are intervening objects in the discharge electrode 20. It is believed that the internal resistance of the discharge electrode 20 is slightly increased by the pores 26 to a degree that does not impair the function of the electrode. It is believed that in conventional transient voltage protection components, the discharge electrode does not contain intervening objects such as pores 26 and should have high conductivity (low resistance). In contrast, in the transient voltage protection component 2 of this embodiment, the average diameter d is greater than 0.45 μm and less than 2.04 μm. P The fine pores 26 within the discharge electrode 20 hinder the movement of charge, allowing current to flow more easily on the surface of the discharge electrode 20 than inside. Furthermore, by concentrating the current more on the surface than inside the discharge electrode 20, it is believed that discharge generated in the gap G between the discharge electrodes 20 is more easily dispersed. As a result, ESD tolerance is improved compared to conventional methods.

[0063] The average diameter d of the pores 26 P With respect to the average thickness T of the discharge electrode 20 DE The ratio (d P / T DE ) can be, for example, 0.03 or more and 0.35 or less, preferably 0.05 or more and 0.25 or less. Furthermore, the area ratio of the pores 26 in the cross section of the discharge electrode 20 is preferably 1.0% or more and 12.4% or less, and more preferably 4.0% or more and 10.0% or less.

[0064] and the average diameter d P The area ratio of the pores 26 can be calculated by performing image analysis on the cross section of the discharge electrode 20. Specifically, the total area of ​​the cross section of the discharge electrode 20 analyzed is set as A. DE The total area of ​​the pores 26 included in the cross section of the analysis is defined as A P The area ratio of the pores 26 can be expressed as “(A P / A DE)×100”. Preferably, when calculating the area ratio of the pore 26, multiple cross-sectional images are analyzed and A DE Set to at least 400 μm 2 .

[0065] like Figure 4A As shown, the discharge induction portion 30 preferably includes at least a ceramic component 31 and metal particles 33, wherein the ceramic component 31 includes glass 31a as a base material and non-glass ceramic particles 31b. Figure 4A In the cross section of the discharge induction portion 30 shown, metal particles 33 and ceramic particles 31 b are dispersed in glass 31 a serving as a base material.

[0066] The metal particles 33 have a melting point (solidus temperature) higher than the sintering temperature of the element body 10. Specifically, as the metal particles 33, Ag particles, Pd particles, Au particles, Pt particles, Cu particles, Ag-Pd alloy particles, Ag-Au alloy particles, Ag-Pt alloy particles, etc. can be used. The metal particles 33 preferably contain at least one of Pd, Ag and Pt as a main component, and preferably use at least one of Pd particles, Pt particles and Ag-Pd alloy particles. Here, the content of the main component contained in each metal particle 33 is preferably 30 wt% or more, more preferably 50 wt% or more. The average particle size d of the metal particles 33 in the cross section of the discharge induction portion 30 is M The area ratio of metal particles 33 in the cross section of discharge induction portion 30 is preferably 10% to 50%, more preferably 15% to 30%.

[0067] The average particle size d of the metal particles 33 M and area ratio by using SEM or STEM Figure 4A The cross section of the discharge induction portion 30 shown in FIG. 3 is obtained, and the image analysis of the obtained cross section photograph is performed to calculate the average particle size d of the metal particles 33. M When the equivalent circle diameters of at least 100 metal particles 33 are measured, the particle size distribution of the metal particles 33 is obtained. In the particle size distribution, the particle size at which the cumulative frequency based on the number is 50% is taken as the average particle size d of the metal particles 33. M In addition, the total area of ​​the cross section of the discharge induction portion 30 analyzed is set to A. AE The total area of ​​the metal particles 33 contained in the cross section is defined as A M The area ratio of the metal particles 33 can be expressed as “(A M / A AE)×100”. Preferably, when calculating the area ratio of the metal particles 33, multiple cross-sectional images are analyzed and A AE Set to at least 400 μm 2 .

[0068] In the cross section of the discharge induction portion 30, the average closest interparticle distance of the metal particles 33 may be 0.20 μm to 1.00 μm, preferably 0.25 μm to 0.81 μm, and more preferably 0.30 μm to 0.65 μm. Setting the average closest interparticle distance within this range can suppress short circuits between the discharge electrodes and more appropriately achieve a low discharge start voltage and good ESD resistance.

[0069] The closest interparticle distance can be calculated by the following procedure. First, a central particle CP (see FIG. 1 ) as a measurement object is arbitrarily selected from the metal particles 33 observed in the cross section of the discharge induction portion 30. Figure 4B ). Then, the metal particle 33 closest to the central particle CP among the other metal particles 33 existing around the selected central particle CP is determined as the nearest particle. Figure 4B In the cross section shown, seven metal particles 33, P1 to P7, exist around the central particle CP, and the metal particle 33 shown by P5 among them corresponds to the nearest particle.

[0070] Next, the distance CD between the centers of gravity of the central particle CP and the nearest particle is measured, and the average particle size d of the metal particles 33 is subtracted from the distance CD between the centers of gravity. M , and the closest inter-particle distance is calculated. That is, Figure 4B The closest interparticle distance between the central particle CP and the nearest particle P5 is shown as “CD-d M Preferably, at least 100 metal particles 33 are arbitrarily selected as central particles CP, the above-mentioned measurement is performed (ie, the number n of the closest inter-particle distance is set to at least 100), and the average of the closest inter-particle distance is calculated.

[0071] Glass 31a is interposed between metal particles 33, bonding the particles together. Furthermore, the presence of glass 31a between the particles helps ensure insulation between the metal particles 33 and the density of the discharge induction portion 30. The content of glass 31a is preferably 10 wt% or greater, more preferably 12 wt% or greater, relative to 100 wt% of the ceramic component in the discharge induction portion 30. The upper limit of the content of glass 31a is not particularly limited and may be 100 wt%, but is preferably 50 wt% or less.

[0072] Glass 31a may also contain, as a main component, one or more components selected from, for example, SiO2, TiO2, and alkaline earth metal components. Here, alkaline earth metal elements are a general term for Be, Mg, Ca, Sr, Ba, and Ra. In this embodiment, "alkaline earth metal component" refers to a compound containing an alkaline earth metal element. Glass 31a may also contain one or more alkaline earth metal components. If the symbol M represents an alkaline earth metal element, the alkaline earth metal component contained in glass 31a is preferably an oxide represented by the chemical formula MO. In particular, glass 31a preferably contains one or more alkaline earth metal components selected from CaO, SrO, and BaO.

[0073] In addition to the above-mentioned main components, glass 31a may also contain other components such as B2O3 and Al2O3. The content of other components is not particularly limited. For example, the content of B2O3 may be 0.1 wt% to 20 wt% relative to 100 wt% of the ceramic component of discharge induction portion 30.

[0074] Glass 31a may also contain alkali metal components such as K2O or Na2O. However, alkali metal components may contribute to the grain growth of metal particles 33. Therefore, the content of alkali metal components in discharge inducing portion 30 is preferably 2 wt% or less relative to 100 wt% of the ceramic component, and more preferably, substantially no alkali metal components are contained. "Substantially no alkali metal components" means that the content of alkali metal components is less than 0.1 wt%. Alkali metal is a general term for Li, Na, K, Rb, Cs, and Fr. In this embodiment, "alkali metal component" refers to a compound containing an alkali metal element. Typically, the alkali metal components contained in glass include Li2O, Na2O, K2O, etc.

[0075] The composition of the above-mentioned glass 31a can be analyzed using various component analysis methods such as energy dispersive X-ray analysis (EDX), electron beam probe microanalyzer (EPMA), electron beam diffraction of TEM, laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS), and fluorescent X-ray analysis (XRF).

[0076] As described above, the ceramic component 31 of the discharge induction portion 30 preferably includes, in addition to the glass 31a, ceramic particles 31b made of a non-glass material. Examples of materials for the ceramic particles 31b include semiconductor compounds such as SnO2 and RuO2, dielectric compounds, zirconium oxide (ZrO2), and amorphous silicon dioxide. More preferably, the ceramic particles 31b are zirconium oxide particles. The average particle size d of the ceramic particles 31b is CA The thickness is not particularly limited, but is preferably, for example, 2.0 μm or less, and more preferably 0.01 μm or more and 1.0 μm or less.

[0077] In addition, when the ceramic particles 31b are zirconium oxide particles, the content of the ceramic particles 31b relative to 100wt% of the ceramic component of the discharge induction section 30 may be 0wt% to 90wt%, preferably 10wt% to 80wt%. In other words, the area ratio of the zirconium oxide particles (ceramic particles 31b) in the cross section of the discharge induction section 30 may be 0% to 85%, preferably 8% to 70%. In addition, the ceramic particles 31b such as zirconium oxide particles dispersed in the glass 31a can be identified by mapping analysis using EDX or EPMA, for example. Therefore, the average particle size d of the ceramic particles 31b is 0%. CA The area ratio can be calculated by analyzing the mapping image and using the same method as in the case of the metal particles 33 .

[0078] Furthermore, the discharge induction portion 30 may include pores having an average diameter of 1.0 μm or less in addition to the above-mentioned ceramic component 31 and metal particles 33 .

[0079] The first external electrode 6 and the second external electrode 8 can each include a baked electrode layer, a resin electrode layer, a plated electrode layer, or the like, and can be composed of a single electrode layer or a stack of multiple electrode layers. Typically, a baked electrode layer or a resin electrode layer is formed as a base electrode in contact with the element body 10, and a single or multiple plated electrode layer is formed on the surface of the base electrode.

[0080] When forming a sintered electrode layer, the sintered electrode layer contains Ag, Cu, Pd, Au, Ni, or an alloy containing at least one of these metal elements as a conductive material. In addition, glass frit or oxide particles may also be included. When forming a resin electrode layer, the resin electrode layer contains the same conductive material as the sintered electrode layer, and further contains a thermosetting resin. When forming a plated electrode layer, the type and number of plated electrode layers can be determined by considering the installation method and usage environment of the transient voltage protection component 2. For example, as the plated electrode layer, Ni plating / Sn plating, Cu plating / Ni plating / Sn plating, Ni plating / Pd plating / Au ​​plating, Ni plating / Pd plating / Ag plating, Ni plating / Ag plating, etc. can be used.

[0081] Then, based on Figure 5 and Figure 6 , an example of a method for manufacturing the transient voltage protection component 2 will be described.

[0082] First, an insulator layer slurry containing the components of the insulator layer 11 is prepared. Specifically, the insulator layer slurry is obtained by adding raw material powder of an insulating material such as glass frit to an organic vehicle containing an organic solvent and an organic binder and kneading them. This slurry is then applied to a PET film using a doctor blade method, for example, and dried appropriately to obtain a plurality of green sheets. In this embodiment, the sheet printed with the discharge portion pattern is referred to as the first green sheet 110, and the sheet not printed with the discharge portion pattern is referred to as the second green sheet 111.

[0083] Next, a discharge induction portion paste is formed on the first green sheet 110. Figure 5 The discharge induction portion pattern 130 is shown. Here, the discharge induction portion paste can be manufactured by kneading glass frit as a raw material of the glass 31a, non-glass ceramic powder such as semiconductor powder or zirconia powder, metal powder, and an organic vehicle.

[0084] The method for mixing the paste for the discharge induction portion is not necessarily limited. For example, a ball mill, a bead mill, a three-roll mill, a homogenizer, or a high-pressure wet micronizer may be used, or a combination of two or more of the above devices may be used. From the perspective of improving the dispersibility of the metal particles 33 in the discharge induction portion 30, it is preferred that the raw materials in the paste for the discharge induction portion be crushed using a high-pressure wet micronizer, and then the paste for the discharge induction portion be mixed using a three-roll mill. In addition, when mixing the paste using the high-pressure wet micronizer, the paste (slurry) input into the device is branched into two paths, so that the branched pastes collide obliquely with each other in a pressurized state (maximum 245MPa) in the chamber. By using the mixing of the high-pressure wet micronizer, the raw materials (glass frit, non-glass ceramic powder, and metal powder, etc.) in the paste for the discharge induction portion can be micronized to improve dispersibility.

[0085] In addition, the discharge inducing portion pattern 130 may be formed by various printing methods such as screen printing, transfer methods, or coating methods.

[0086] Next, a discharge electrode paste is formed on the first green sheet 110. Figure 5 The conductive pattern 120 is shown. The discharge electrode paste is produced by adding the conductive powder, which is the raw material of the metal conductor portion 25, and the burn-off material for forming the pores 26, to an organic vehicle and kneading them. As the burn-off material, various resin beads such as acrylic resin beads, carbon black, polystyrene, polyurethane, or polyvinylbenzene can be used, and acrylic resin beads are preferably used. The average diameter d of the pores 26 is PThe area ratio can be controlled based on the particle size and mixing ratio of the resin beads added to the discharge electrode paste. The method for kneading the discharge electrode paste is not particularly limited; for example, a ball mill, a bead mill, a three-roll mill, a homogenizer, or a high-pressure wet micronizer may be used. A combination of two or more of these devices may also be used.

[0087] The conductive pattern 120 is formed along the X-axis direction, spanning the surface of the first green sheet 110 and the surface of the discharge inducing portion pattern 130. Furthermore, the conductive pattern 120 has a slit S of a predetermined width on the surface of the discharge inducing portion pattern 130. This slit S is a cutout portion where the conductive pattern 120 is not printed, and forms a gap G after firing. The conductive pattern 120 can also be formed using the same method as the discharge inducing portion pattern 130.

[0088] Next, a cavity pattern 150 is formed on the first green sheet printed with the discharge inducing portion pattern 130 and the conductor pattern 120 using a cavity varnish. The cavity varnish contains an organic solvent and an organic binder that are burned off during firing. The cavity pattern 150 is used to form an internal space at the portion facing the discharge electrode. Figure 5 As shown, the cavity pattern 150 is preferably formed to cover a portion of the conductor pattern 120 forming the opposing portions 21b and 22b and the discharge inducing portion pattern 130. Through the above steps, the first green sheet 110 printed with the discharge portion pattern including the discharge inducing portion pattern 130, the conductor pattern 120, and the cavity pattern 150 is obtained.

[0089] Next, the first green sheet 110 having the pattern for the discharge portion and the plurality of second green sheets 111 are stacked and pressed in the stacking direction to obtain a green chip 100. Figure 6 As shown, the first green sheets 110 are stacked between the second green sheets 111. The number of stacked second green sheets 111 is not particularly limited, and the number of stacked second green sheets 111 above and below the first green sheet 110 may be different.

[0090] In addition, Figure 5 and Figure 6 For simplicity, the process of forming a single green chip is shown. However, in actual manufacturing, a green sheet larger than the element body 10 in the XY plane is typically prepared, and multiple discharge portion patterns are continuously printed on the surface of this green sheet. This green sheet is then used to form a mother laminate, which is then cut at predetermined intervals to obtain multiple green chips.

[0091] Next, the green chip 100 obtained through the above steps is fired to form the element body 10. The firing conditions are not particularly limited; they can be selected based on the components contained in the element body 10. For example, the holding temperature can be set to 800°C to 1200°C, the temperature holding time can be set to 0.1 to 3 hours, and the firing atmosphere can be air, an inert gas, or a reducing atmosphere. During this firing process, the cavity pattern 150 is burned away, forming the cavity portion 15 in the stacked portion of the cavity pattern 150. Furthermore, the resin beads (burnable material) in the conductive pattern 120 are burned away during the firing process, forming the pores 26 within the discharge electrode 20. Furthermore, a debindering treatment may be appropriately performed before the firing process. If firing is performed in a reducing atmosphere, a reoxidation treatment may be performed after firing, or a heat treatment to remove strain may be performed after firing.

[0092] Next, a pair of external electrodes 6 and 8 are formed on the surface of the element body 10 obtained by the above steps. The method for forming the external electrodes 6 and 8 is not particularly limited. For example, when forming the external electrodes 6 and 8 by sintering electrode layers, a conductive paste containing glass frit is applied to the end faces of the element body 10, and then the element body 10 is heat-treated under specified conditions (for example, in the atmosphere at 600 to 800°C for 1 to 5 hours). In addition, when forming the external electrodes 6 and 8 by resin electrodes, a conductive paste containing thermosetting resin is applied to the end faces of the element body 10, and then the element body 10 is heated at a temperature at which the thermosetting resin cures. Furthermore, after forming the sintered electrodes or resin electrodes by the above method, sputtering, vapor deposition, electrolytic plating, or chemical plating can be performed to form the external electrodes 6 and 8 having a multilayer structure.

[0093] Through the above manufacturing process, we can obtain Figure 1 The transient voltage protection component 2 is shown.

[0094] (Summary of the First Embodiment)

[0095] The transient voltage protection component 2 of this embodiment includes a pair of discharge electrodes 20 facing each other via a gap G, and a discharge induction portion 30 in contact with the pair of discharge electrodes 20. The discharge electrodes 20 include a discharge electrode having an average diameter d of 0.45 μm or more and 2.04 μm or less. P The pores 26.

[0096] The transient voltage protection component 2 has the above-mentioned features, and can maintain a low discharge start voltage while improving ESD tolerance compared to conventional devices. The reason for the improvement in ESD tolerance is not necessarily clear, but is believed to be the following.

[0097] Discharge electrodes generally prefer high density and high conductivity. However, in the transient voltage protection component 2 of this embodiment, contrary to conventional wisdom, the fine pores 26 in the discharge electrode 20 are believed to function as intermediaries that hinder charge transfer, slightly increasing the internal resistance of the discharge electrode 20. Specifically, the fine pores 26 make the surface resistance of the discharge electrode 20 relatively lower than that of the interior, making it easier for current to concentrate on the surface of the discharge electrode 20. This is believed to disperse the locations where discharge occurs in the gaps G between the discharge electrodes 20, improving ESD tolerance.

[0098] The area ratio of the pores 26 in the cross section of the discharge electrode 20 is preferably 1.0% or more and 12.4% or less. By setting the area ratio of the pores 26 within the above range, the ESD tolerance can be further improved.

[0099] Preferably, discharge induction section 30 includes glass 31a, metal particles 33 dispersed in glass 31a, and ceramic particles 31b (zirconia particles, etc.) The discharge induction section 30 having the above structure can suppress short circuit failures and further improve ESD tolerance.

[0100] Second embodiment

[0101] The following is based on Figure 3B The second embodiment of the present disclosure will now be described. In the second embodiment, the internal structure of the discharge electrode 20 differs from that of the first embodiment, but the remaining structures are the same as those of the first embodiment. In the second embodiment, common structures with the first embodiment are denoted by the same reference numerals as in the first embodiment, and their descriptions are omitted.

[0102] In the first embodiment, the discharge electrode 20 has the pores 26 as the intermediary for increasing the internal resistance. However, as such an intermediary, fine ceramic particles may be dispersed inside the discharge electrode 20 instead of the pores 26. Specifically, the discharge electrode 20α in the second embodiment is as follows: Figure 3B As shown, the metal conductor portion 25 and ceramic particles 27 dispersed inside the metal conductor portion 25 are included.

[0103] The ceramic particles 27 contained in the discharge electrode 20α may contain, for example, silicon dioxide (SiO2), TiO2, Al2O3, CaO, SrO, or BaO, preferably containing silicon dioxide as a main component. The main component in the ceramic particles 27 refers to the component with the highest content in the ceramic particles 27. When the main component of the ceramic particles 27 is silicon dioxide, the ceramic particles 27 may be composed solely of SiO2 or may contain trace elements in a solid solution.

[0104] The average particle size d of the ceramic particles 27 CEThe average particle size d is 0.05 μm or more and 0.54 μm or less, preferably 0.10 μm or more and 0.50 μm or less, and more preferably 0.15 μm or more and 0.40 μm or less. CE The ceramic particles 27 are dispersed inside the discharge electrode 20α, and similarly to the first embodiment, the discharge start voltage can be maintained low while improving the ESD tolerance compared to conventional methods. In other words, the ceramic particles 27 play the same role as the pores 26 in the first embodiment.

[0105] Specifically, it is considered that: CE Similar to the pores 26 in the first embodiment, the ceramic particles 27 act as intermediaries within the discharge electrode 20α, hindering charge transfer and slightly increasing the internal resistance. Specifically, it is believed that the ceramic particles 27 make the resistance on the surface of the discharge electrode 20α relatively lower than that within the interior, allowing current to concentrate on the surface of the discharge electrode 20α. Furthermore, it is believed that the slight increase in internal resistance of the discharge electrode 20α due to the ceramic particles 27 converts some of the electrical energy of the discharge electrode 20α into heat. As described above, this current concentration on the surface and / or the conversion of electrical energy into heat disperses the locations where discharge occurs in the gap G between the discharge electrodes 20α, improving ESD tolerance.

[0106] The average thickness T of the discharge electrode 20α DE The average thickness of the discharge electrode 20 can be set in the same range as that of the first embodiment. CE Relative to the average thickness T DE The ratio (d CE / T DE ) can be, for example, 0.005 or greater and 0.30 or less, preferably 0.01 or greater and 0.10 or less. Furthermore, the area ratio of ceramic particles 27 in the cross section of discharge electrode 20α is preferably 0.4% or greater and 5.1% or less, more preferably 0.6% or greater and 2.0% or less. Setting the area ratio of ceramic particles 27 within the above range can further improve ESD tolerance.

[0107] The average particle size d of the ceramic particles 27 CE The area ratio can be analyzed by the same method as that of the pores 26. Specifically, it is preferred to analyze the cross section of the discharge electrode 20α by image analysis, determine the equivalent circle diameters of at least 100 ceramic particles 27, and calculate the average particle size d CE In this image analysis, the total area of ​​the interface analyzed by the discharge electrode 20α is set to A. DE The total area of ​​the ceramic particles 27 included in the cross section is defined as ACE The area ratio of the ceramic particles 27 can be expressed as “(A CE / A DE )×100”. Preferably, when calculating the area ratio of the ceramic particles 27, multiple cross-sectional images are analyzed and A DE Set to at least 400 μm 2 Furthermore, the metal conductor portion 25 and the ceramic particles 27 can be identified based on contrast in a cross-sectional SEM image or STEM image.

[0108] When ceramic particles 27 are dispersed within discharge electrode 20α, discharge induction section 30 preferably includes glass 31a as a base material, metal particles 33 dispersed within glass 31a, and ceramic particles 31b. In the second embodiment, the discharge induction section 30 having the above-described structure can suppress short-circuit failures and further improve ESD tolerance.

[0109] Third embodiment

[0110] The following is based on Figure 3C The third embodiment of the present disclosure will now be described. In the third embodiment, the internal structure of the discharge electrode 20 differs from that of the first embodiment, but the remaining structures are the same as those of the first embodiment. In the third embodiment, common structures with the above-mentioned embodiments are denoted by the same reference numerals as those in the above-mentioned embodiments, and their descriptions are omitted.

[0111] The discharge electrode 20β in the third embodiment is as follows Figure 3C As shown, the discharge electrode 20β includes a metal conductor 25, fine pores 26 dispersed within the metal conductor 25, and ceramic particles 27. Specifically, the discharge electrode 20β includes both the fine pores 26 of the first embodiment and the ceramic particles 27 of the second embodiment as intervening substances. By including both the fine pores 26 and ceramic particles 27 in the discharge electrode 20β, ESD resistance can be further improved compared to the first and second embodiments.

[0112] In addition, when the discharge electrode 20β includes both the pores 26 and the ceramic particles 27, the average diameter d of the pores 26 is P The area ratio is preferably set within the range described in the first embodiment, and the average particle size d of the ceramic particles 27 is preferably set within the range described in the first embodiment. CE and the area ratio are preferably set within the range described in the second embodiment.

[0113] (Variation)

[0114] As mentioned above, although embodiment of this disclosure was described, this disclosure is not limited to the said embodiment, Various changes are possible within the range which does not deviate from the summary of this disclosure.

[0115] For example, a pair of discharge electrodes 20 may be opposed to each other in the Y-axis direction. Figure 7A In the transient voltage protection component 2a shown, the side edge 21c of the first discharge electrode 21 and the side edge 22c of the second discharge electrode 22 along the Y axis are opposed to each other with a gap G therebetween. That is, the side edges 21c and 22c are opposed to each other, and discharge when a transient voltage such as ESD occurs occurs between the side edges 21c and 22c. Figure 7A As shown, by making the discharge electrodes 20 face each other at the side edges 21c and 22c, the length L of the facing portion of the discharge electrodes 20 on the discharge induction portion 30 can be made longer than when they face each other at the end portions. G Bigger. Figure 7A In the transient voltage protection component 2a shown, the length L of the relative portion is G The ratio of the width of the gap G in the Y-axis direction (L G / G) can be set to 0.3 or more, and is preferably 0.5 or more and 50 or less.

[0116] exist Figure 2A and Figure 2B In the embodiment, a single cavity 15 is formed to cover the facing portion of the discharge inducing portion 30 and the discharge electrode 20. However, multiple cavities 15 may be formed above the discharge electrode 20 and the discharge inducing portion 30 along the Z axis. Furthermore, if a pair of discharge electrodes 20, the discharge inducing portion 30, and the cavity 15 are defined as a discharge cell, the element body 10 may include multiple discharge cells. Furthermore, the transient voltage protection component may not have the cavity 15, and the discharge inducing portion 30 may be filled between the pair of discharge electrodes.

[0117] like Figure 7B As shown, the element body 10 may include a coil 40. Furthermore, the element body 10 may include a capacitor unit. The capacitor unit can be formed by stacking internal electrode layers between insulating layers 11, for example.

[0118] Example

[0119] Hereinafter, the present disclosure will be described based on more detailed examples, but the present disclosure is not limited to these examples.

[0120] (Example 1)

[0121] First, prepare the insulator layer paste, the discharge induction unit paste, the discharge electrode paste, and the cavity varnish. Glass and zirconium oxide, the raw material powders for the insulator layer, are added to the insulator layer paste along with the organic vehicle. The discharge induction unit paste is prepared by mixing the organic vehicle, glass frit, Pd powder with an average particle size of 0.5 μm, and zirconium oxide powder with an average particle size of 0.05 μm, then kneading the mixture on a three-roll mill. Furthermore, glass frit containing SiO2, SrO, and CaO is used in the production of the discharge induction unit paste.

[0122] The discharge electrode paste is made using Pd powder with an average particle size of 0.5 μm, acrylic resin beads (burned-out material) with an average particle size of 1 μm, and an organic vehicle as raw materials. These raw materials are mixed and then kneaded using a three-roll mill to produce the discharge electrode paste. The acrylic resin beads are incorporated into the discharge electrode paste at a ratio of 3 vol%.

[0123] Next, a green sheet is prepared using the above-mentioned insulator layer slurry. Then, a discharge induction portion paste, a discharge electrode paste, and a cavity varnish are applied to the green sheet in the order described to form a discharge portion pattern.

[0124] Next, the green sheet printed with the discharge portion pattern and the green sheet without the discharge portion pattern are placed in a Figure 6 The mother laminate is then cut into pieces to obtain a plurality of green chips.

[0125] Next, each green chip is fired in an atmosphere at 800-1200°C for 0.1-1 hour to obtain a sintered body. Then, a conductive paste containing Ag is applied to the outer surface of each body, and the body is heated at 700°C for 1 hour to form a sintered electrode containing Ag. Figures 1 to 2B The transient voltage protection components of the structure shown.

[0126] In addition, the dimensions of the element body are 1 mm in width in the X-axis direction, 0.5 mm in width in the Y-axis direction, and 0.5 mm in height in the Z-axis direction. The average thickness of the discharge induction portion is 5 μm, the average thickness of the discharge electrodes is 5 μm, and the width of the gap G (the relative distance between the discharge electrodes) is 50 μm.

[0127] (Example 2 and Example 3)

[0128] In Examples 2 and 3, discharge electrode pastes were prepared using Pd powder (same specifications as in Example 1), acrylic resin beads, and an organic vehicle (same specifications as in Example 1) as raw materials, similar to Example 1. However, acrylic resin beads with a larger average particle size than in Example 1 were used, and the proportion of acrylic resin beads was increased. Specifically, in Example 2, acrylic resin beads with an average particle size of 1 μm were used, and the proportion of acrylic resin beads was set to 12 vol%. In Example 3, acrylic resin beads with an average particle size of 1 μm were used, and the proportion of acrylic resin beads was set to 16 vol%.

[0129] In Examples 2 and 3, as described above, the structure of the discharge electrode paste was different from that of Example 1, but the manufacturing conditions other than the discharge electrode paste were the same as those of Example 1 to manufacture transient voltage protection components.

[0130] (Example 4 to Example 6)

[0131] In Examples 4 to 6, silica powder was added to the discharge electrode paste instead of the acrylic resin beads used as the burn-off material. Specifically, in Example 4, silica powder with an average particle size of 0.05 μm was used, and the silica powder content in the discharge electrode paste was set to 1 vol%. In Example 5, silica powder with an average particle size of 0.05 μm was used, and the silica powder content in the discharge electrode paste was set to 2 vol%. In Example 6, silica powder with an average particle size of 0.05 μm was used, and the silica powder content in the discharge electrode paste was set to 7 vol%. Furthermore, the Pd powder and organic vehicle added to the discharge electrode paste had the same specifications as those in Example 1.

[0132] In Examples 4 to 6, as described above, the structure of the discharge electrode paste was different from that of Example 1, but the manufacturing conditions other than the discharge electrode paste were the same as those of Example 1, and transient voltage protection components were manufactured.

[0133] (Example 7 to Example 9)

[0134] In Examples 7 to 9, both acrylic resin beads and silica powder were added to produce discharge electrode pastes. In the discharge electrode pastes of Examples 7 to 9, the same specifications of Pd powder and organic vehicle as in Example 1 were used.

[0135] In Example 7, acrylic resin beads with an average particle size of 1 μm and silica powder with an average particle size of 0.05 μm were used. The acrylic resin beads were mixed at a ratio of 3 vol% and the silica powder at a ratio of 1 vol% in the discharge electrode paste.

[0136] In Example 8, acrylic resin beads with an average particle size of 1 μm and silica powder with an average particle size of 0.05 μm were used. The acrylic resin beads were mixed at a ratio of 12 vol% and the silica powder at a ratio of 2 vol% in the discharge electrode paste.

[0137] In Example 9, acrylic resin beads with an average particle size of 1 μm and silica powder with an average particle size of 0.05 μm were used. The acrylic resin beads were mixed at a ratio of 12 vol% and the silica powder at a ratio of 7 vol% in the discharge electrode paste.

[0138] In Examples 7 to 9, as described above, the structure of the discharge electrode paste was different from that of Example 1, but the manufacturing conditions other than the discharge electrode paste were the same as those of Example 1 to manufacture transient voltage protection components.

[0139] (Comparative Example 1)

[0140] In Comparative Example 1, a discharge electrode paste containing no burnt-off material or ceramic powder was prepared using only an organic vehicle and Pd powder with an average particle size of 0.5 μm as raw materials. In Comparative Example 1, the manufacturing conditions other than the discharge electrode paste were identical to those in Example 1, and a transient voltage protection component was produced.

[0141] (Comparative Example 2)

[0142] In Comparative Example 2, acrylic resin beads with an average particle size of 1 μm were mixed and kneaded with Pd powder (same specifications as in Example 1) and an organic vehicle (same specifications as in Example 1) to produce a discharge electrode paste. The acrylic resin bead ratio in Comparative Example 2 was higher than in the previous example, at 25 vol%. Other than the discharge electrode paste, the manufacturing conditions were the same as in Example 1 to produce the transient voltage protection component of Comparative Example 2.

[0143] The transient voltage protection components of the respective examples and comparative examples were subjected to the following evaluations.

[0144] (Analysis of discharge electrode)

[0145] Cut off the transient voltage protection component to Figure 2AThe cross section shown in FIG. 1 is mirror-polished after cutting. Furthermore, the cross section of the discharge electrode is observed with an SEM to determine the average diameter of the pores contained in the discharge electrode, the area ratio of the pores, the average particle size of the ceramic particles, and the area ratio of the ceramic particles. The average diameter of the pores is calculated by measuring the equivalent circle diameter of 100 pores, and the average particle size of the ceramic particles is calculated by measuring the equivalent circle diameter of 100 ceramic particles. In addition, when calculating the area ratio of the pores and the area ratio of the ceramic particles, the total area of ​​the cross section of the discharge electrode to be analyzed is set to 400 μm 2 .

[0146] (Evaluation of discharge characteristics)

[0147] The discharge inception voltage (kV) and ESD withstand voltage (kV) of each sample were measured using the electrostatic discharge immunity test specified in IEC61000-4-2. For the discharge inception voltage, a value of 2.3 kV or less was considered good. For the ESD withstand voltage, a value of 14 kV or greater was considered good, and a value of 16 kV or greater was considered particularly good.

[0148] The evaluation results of each example and each comparative example are shown in Table 1. In addition, the "-" shown in the analysis result column of the discharge electrode in Table 1 indicates that pores or ceramic particles as intervening substances are not present inside the discharge electrode (no pores or ceramic particles can be observed at an observation magnification of 5000 times).

[0149] [Table 1]

[0150]

[0151] As shown in Table 1, in Comparative Example 1, the discharge electrode contained no pores or ceramic particles and had an ESD withstand voltage of less than 14 kV. Furthermore, in Comparative Example 2, the discharge electrode contained pores with an average diameter of 3.05 μm, but had an ESD withstand voltage of less than 14 kV.

[0152] On the other hand, in Examples 1 to 3, it was confirmed that the discharge electrode contained pores with an average diameter of 0.45 μm to 2.04 μm (rounded to the second decimal place, 0.5 μm to 2.0 μm). In Examples 1 to 3, ESD withstand voltage was improved compared to Comparative Examples 1 and 2, achieving an ESD withstand voltage of 14 kV or higher. The evaluation results of Examples 1 to 3 indicate that by forming pores with an average diameter of 0.45 μm to 2.04 μm in the discharge electrode, ESD withstand voltage was improved while maintaining a low discharge start voltage. Furthermore, the evaluation results of Examples 1 to 3 indicate that the area ratio of the pores in the discharge electrode cross section is preferably 1.0% to 12.4% (rounded to the first decimal place, 1% to 12%).

[0153] Furthermore, in Examples 4 to 6, it was confirmed that the discharge electrode contained silica particles having an average particle size of 0.05 μm to 0.54 μm (rounded to the second decimal place, an average particle size of 0.1 μm to 0.5 μm). In Examples 4 to 6, ESD resistance was improved compared to Comparative Examples 1 and 2, achieving an ESD resistance of 14 kV or higher. The evaluation results of Examples 4 to 6 indicate that by dispersing ceramic particles having an average particle size of 0.05 μm to 0.54 μm in the discharge electrode, a low discharge start voltage can be maintained while improving ESD resistance. Furthermore, the evaluation results of Examples 4 to 6 indicate that the area ratio of the ceramic particles in the discharge electrode cross-section is preferably 0.4% to 5.1%.

[0154] In Examples 7 to 9, it was confirmed that the discharge electrode contained both pores and silica particles, further improving ESD tolerance compared to Examples 1 to 6. These results demonstrate that dispersing both pores of a predetermined particle size and ceramic particles within the discharge electrode further improves ESD tolerance.

[0155] (Examples 10 to 13)

[0156] In Examples 10 to 13, the materials of the discharge electrodes were changed from those in the above-mentioned examples to produce transient voltage protection components of Examples 10 to 13. This will be described in detail below.

[0157] In Example 10, a transient voltage protection component was obtained in the same manner as in Example 2 except that Pt powder having an average particle size of 0.5 μm was used instead of Pd powder having an average particle size of 0.5 μm to prepare the discharge electrode paste.

[0158] In Example 11, a transient voltage protection component was obtained in the same manner as in Example 5 except that Pt powder having an average particle size of 0.5 μm was used instead of Pd powder having an average particle size of 0.5 μm to prepare the discharge electrode paste.

[0159] In Example 12, a transient voltage protection component was obtained in the same manner as in Example 8 except that Pt powder having an average particle size of 0.5 μm was used instead of Pd powder having an average particle size of 0.5 μm to prepare the discharge electrode paste.

[0160] In Example 13, a transient voltage protection component was obtained in the same manner as in Example 8 except that Ag—Pd alloy powder having an average particle size of 0.5 μm was used instead of Pd powder having an average particle size of 0.5 μm to prepare the discharge electrode paste.

[0161] In Examples 10 to 13, analysis of the discharge electrode and evaluation of discharge characteristics were carried out in the same manner as in Examples 1 to 9. Table 2 shows the evaluation results.

[0162] [Table 2]

[0163]

[0164] As shown in Table 2, even when the raw materials of the metal conductor portion are different, dispersing pores and / or ceramic particles within the discharge electrode can maintain a low discharge start voltage and achieve improved ESD resistance. In particular, the results of Examples 10 to 12 show that the inclusion of both pores and ceramic particles can further improve ESD resistance compared to the inclusion of either pores or ceramic particles. Furthermore, using Pt as the discharge electrode can further improve ESD resistance.

[0165] Description of Reference Numerals

[0166] 2, 2a, 2b…Transient voltage protection components

[0167] 10…body

[0168] 10a…end face

[0169] 10b…side

[0170] 10c…main surface

[0171] 11…Insulator layer

[0172] 20, 20α, 20β…discharge electrodes

[0173] 21…first discharge electrode

[0174] 22…Second discharge electrode

[0175] 21a, 22a…lead-out portion

[0176] 21b, 22b…Relative parts

[0177] 25…Metal conductor part

[0178] 26…fine pores

[0179] 27…Ceramic particles (in the discharge electrode)

[0180] 30…Discharge induction unit

[0181] 31…ceramic composition

[0182] 31a…Glass

[0183] 31b…Ceramic particles (in the discharge induction section)

[0184] 33…Metal particles

[0185] 15…Cavity

[0186] 6…First external electrode

[0187] 8…Second external electrode

[0188] 100…green chips

[0189] 110…First green sheet

[0190] 120…conductor pattern

[0191] 130…Pattern for discharge induction unit

[0192] 150…cavity pattern

[0193] 111…Second raw film.

Claims

1. A transient voltage protection component, wherein: The device comprises a pair of discharge electrodes facing each other with a gap therebetween, and a discharge inducing portion in contact with the pair of discharge electrodes. The discharge electrode includes pores having an average diameter of 0.45 μm or more and 2.04 μm or less.

2. The transient voltage protection component according to claim 1, wherein: An area ratio of the pores in a cross section of the discharge electrode is 1.0% or more and 12.4% or less.

3. The transient voltage protection component according to claim 1 or 2, wherein: The discharge induction portion includes a base material made of glass, and metal particles and ceramic particles dispersed in the base material.

4. The transient voltage protection component according to claim 1 or 2, wherein: The discharge electrode further includes ceramic particles having an average diameter of 0.05 μm or more and 0.54 μm or less.

5. The transient voltage protection component according to claim 1 or 2, wherein: The discharge electrode contains at least one of Pd, Ag, and Pt as a main component.

6. A transient voltage protection component, wherein: The device comprises a pair of discharge electrodes facing each other with a gap therebetween, and a discharge inducing portion in contact with the pair of discharge electrodes. The discharge electrode includes ceramic particles having an average diameter of 0.05 μm or more and 0.54 μm or less.

7. The transient voltage protection component according to claim 6, wherein: An area ratio of the ceramic particles in a cross section of the discharge electrode is 0.4% or more and 5.1% or less.

8. The transient voltage protection component according to claim 6 or 7, wherein: The ceramic particles contain SiO2 as a main component.

9. The transient voltage protection component according to claim 6 or 7, wherein: The discharge induction portion includes a base material made of glass, and metal particles and ceramic particles dispersed in the base material.

10. The transient voltage protection component according to claim 6 or 7, wherein: The discharge electrode further includes pores having an average diameter of 0.45 μm or more and 2.04 μm or less.

11. The transient voltage protection component according to claim 6 or 7, wherein: The discharge electrode contains at least one of Pd, Ag, and Pt as a main component.

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