Patent Application
20050128678
This invention relates to an electronic component which is suitably used for electronic devices etc. such as modems, power supply circuits, power supplies for use in liquid crystal displays, DC-DC converters, and power line communication devices.
In electronic devices such as modems and power supply circuits, a number of electronic components are incorporated. For example, capacitors are likely to be used for noise elimination, cut off a DC component of signals, and so on.
Generally speaking, miniaturization and low-cost are asked for electronic devices. Coming up with this, significant miniaturization and low-cost are asked also as to electric components. For the purpose of reduction of mounting cost by use of automatic mounting and reduction of a mounting area, surface mount type electronic components are often asked. On one hand, conflicting specifications are often asked, such as high performance, reduction of fluctuations in characteristics, and improvement of endurance, in addition to miniaturization.
Coming up with advent of LSI with a large number of pins, etc., and increase of signal lines, it becomes necessary to mount a plurality of electronic components with high-density, in a place where an interval of wiring is very narrow.
In particular, data output and data input are likely to be a set in modems etc., and in that case, it is necessary to mount two electronic components by all means.
In order to satisfy these, various electronic components have been proposed in Japanese Patent Laid Open No. 2001-110691 and 2002-43170.
However, conflicting problems are produced for accomplishment of miniaturization and high performance, and to accomplish them simultaneously produces technically difficult problems.
For example, in order to respond to reduction of fluctuations of performances and characteristics, or improvement of endurance, an electronic component molded with an armoring material made of resin etc. has been proposed. However, in a case that a plurality of electronic components of this type are intended to be mounted, there is a problem of growing in size since the electronic components are molded. There are also problems of a substrate growing in size due to wiring layout, and radiation or signal delay due to the wiring layout.
On the contrary, in a case that bare electronic components, which are not molded, were mounted adjacently, for the purpose of realizing miniaturization and high-density mounting, it causes problems of short-circuiting or cross talk of signals, due to generation of electric field coupling, between electronic components.
In particular, in capacitors as capacitance elements, electric field coupling is generated between adjacent capacitors, and cross talk etc. are easily generated, and it also becomes a cause of noises. In a circuit substrate of an electronic equipment in which an input and an output are likely to be paired wirings, these are very important problems.
In a case that a plurality of elements are molded with armoring material, in order to solve these, when there is filling failure of the armoring material as resin between the elements, it causes such a problem that a withstand voltage between the elements is lowered. In addition, there is a problem also in endurance to a heat cycle, etc., in a case that an interval between the elements is small. In a case that the interval between elements is enlarged in order to avoid these, it causes such a problem that it is impossible to realize miniaturization, and after all, miniaturization of electronic devices is disturbed.
An object of this invention is to solve the above-described problems, and to provide an electronic component which realizes conflicting specifications such as miniaturization of an electronic device, high-density mounting, high performance, reduction of fluctuation, improvement of endurance, simultaneously.
In order to accomplish the above-described object, an electronic component of this invention has a plurality of elements, a pair of terminal parts which are disposed in the element, and an armoring material member which covers at least a part of the element and the terminal part, and a length P1, a width P2, and a height P3 of the armoring material is in the range of:
3.2 mm≦P1≦7.1 mm
2.5 mm≦P2≦6.3 mm
1.5 mm≦P3≦2.4 mm.
In this specification, it will be described by use of a multilayer type capacitor as an example, but this invention is not limited to this. It may be various elements such as a normal capacitor which is not laminated, and a resistor. It may be also a single plate capacitor.
Hereinafter, it will be described by use of the drawings.
(Embodiment 1)
In the figures, reference numeral 1 designates a multilayer type capacitor; reference numeral 2 designates a dielectric base body of the capacitor 1; reference numeral 3 designates inner electrodes of the capacitor 1; reference numeral 4 designates terminal parts of the capacitor 1; reference numerals 5, 6 designate lead terminals; reference numeral 7 designates an electronic component; reference numeral 8 designates an armoring material; reference numeral 9 designates an opposed region; reference numeral 10 designates a chamfer; reference numeral 11 designates a non-parallel part; reference numeral 12 designates an arc part; reference numeral 13 designates an opposed distance; reference numerals 14, 15 designate mounted components; reference numerals 16, 17 designate circuit substrates; and reference numerals 18, 19 designate wirings.
Multilayer type capacitor 1 is one example of an element, and it may be also an element such as a non-multilayer type capacitor, a resistor, an inductor, and a filter, other than this. Chamfer 10 shown in
As shown in
By configuring in this manner, since two multilayer type capacitors 1 (i.e., two elements) are housed in one electronic component 7, it is possible to mount two multilayer type capacitors 1 on the circuit substrate at once. Since each of them is molded, endurance is high. It is possible to reduce a mounting area as compared to mounting them separately.
Hereinafter, detail of each part will be described.
Multilayer type capacitor 1 will be first described by use of
Dielectric base body 2 is a base body which was configured by a dielectric material, and for example, titanium oxide, barium titanate, etc. are preferably used. Alumina etc. may be also used. By use of the such like materials, it is properly formed with a necessary shape and size.
Inner electrode 3 is an electrode which is embedded in dielectric base body 2. As a constituent material of inner electrode 3, cited is a metal material which includes at least one of Ni, Ag, Pd, Cu, Au and so on. In particular, use of Ni or Ni alloy becomes advantageous in cost. It may be also an alloy of these, and a thing having a plating-processed surface. As a matter of course, it may be also an alloy etc. A thickness of inner electrode 3 is 1˜5 μm. An interval between adjacent inner electrodes 3 is preferably 15 μm or more.
Inner electrode 3 is electrically connected to terminal parts 4. More specifically, inner electrode 3 which is connected only to one of terminal parts 4, and inner electrode 3 which is connected to the other of terminal parts 4 are opposed to each other. Capacitance is mainly generated between these opposed inner electrodes 3.
Terminal parts 4 are connected to inner electrode 3, and disposed to dielectric base body 2 in a pair. They are normally likely to be disposed at both ends of base body 2. As a special thing, they may be also disposed at places other than the both ends. For example, they may be formed on the top and bottom of dielectric base body 2, and these terminal parts 4 which are formed on the top and bottom, and lead terminals 5, 6 which will be described later, may be connected to each other. Terminal parts 4 may be formed by a material which contains at least one of Cu, Zn, Ni, Ag, Au and so on, and a plating process of a single layer or multiple layers may be applied to its surface.
Terminal parts 4 may be configured by joining a metal cap to dielectric base body 2. Outermost parts (surface parts) of terminal parts 4 are preferably configured by a conductive material which has a melting point of 200° C. or more. By this configuration, even if high temperature is applied to an electronic component in a re-flow process etc., thermal damage is not added to terminal parts 4.
As one example of a concrete manufacturing method of multilayer type capacitor 1, a plurality of such dielectric sheets that inner electrode 3 is applied to one surface are prepared, and these dielectric sheets are laminated in such a manner that electrodes are not directly contacted, and terminal parts 4 are formed at both ends of this laminated body.
At this time, a dimension of multilayer type capacitor 1 is, assuming that its length is L1, a width is L2, and a height is L3, configured so as to fall within the range of
2.0 mm≦L1≦5.7 mm
0.8 mm≦L2≦5.0 mm
1.0 mm≦L3≦1.5 mm.
When L1 through L3 are made smaller than the above-described lower limits, a forming area of inner electrode 3 becomes insufficient, and an interval between inner electrodes 3 becomes narrow, and the number of inner electrodes 3 has to be reduced. Thus, it becomes difficult to obtain a large capacitance value, and it becomes difficult to obtain electronic component 7 which has a wide range of capacitance.
A dimension of the armoring material is, assuming that a length is P1, a height is P2, and a width is P3, configured so as to fall within the range of
3.2 mm≦P1≦7.1 mm
2.5 mm≦P2≦6.3 mm
1.5 mm≦P3≦2.4 mm.
By making an element (multilayer type capacitor 1) of a size which falls within the above-described range or an electronic component with an armoring material which falls within the above-described range, it is possible to realize miniaturization of electronic devices, and electronic components which are asked for narrowing an interval between conductive lines.
For example, by disposing a plurality pairs of terminal parts 4 on an end surface of the base body which is formed by ceramic etc. such as alumina, it is also preferable to form a plurality of electric elements such as capacitors and multilayer type capacitors 1, although they are single from the view point of an element.
At this time, for example, if the element is multilayer type capacitor 1, inner electrode 3 in the base body is divided with respect to each terminal parts 4 being in pairs, and terminal parts 4 are connected to them, respectively. As a result, it is possible to form a plurality of parallel multilayer type capacitors 1 as a single element body. In a case of other electric elements such as single plate capacitors, resistors, and inductors, a plurality of them are housed in one base body so as to be aligned in parallel, and each of them is connected to terminal part 4, and thereby, it is possible to configure a plurality of electric elements as a single element body.
By use of an element such as multilayer type capacitor 1 which is composed of a single element body, there is such a merit that it is possible to make easy manufacture of elements, and as a result, also to make easy manufacture of electronic component 7, or there is such a merit that miniaturization is further facilitated.
In
A single piece of an element as shown in
Lead terminals 5, 6 will be then described.
Lead terminals 5, 6 are, as apparent from
As a major constituent material of lead terminals 5, 6, a metal material, which is selected from at least one of Fe, Cu, and Ni, is preferably selected. Use of these materials is advantageous in an aspect of an electric characteristic and workability. An alloy of these metals may be also used, and a plating process of a single layer or multiple layers may be applied to its surface.
Lead terminals 5, 6 have joint parts which are jointed to terminal parts 4, elongated parts which are elongated toward an outside of armoring material 8, and mounting parts 5a, 6a which are further folded back to be connected to wirings of the circuit substrate. As shown in
In a case that terminal parts 4 are disposed on and beneath dielectric base body 2, but not at its both sides, and in tune with this, lead terminals 5, 6 may be pulled out to an outside of armoring material 8, in such a mode that they are connected above and below, alternately.
By pulling out lead terminals 5, 6 from surfaces of armoring material 8, which are opposed to each other, respectively, it is possible to widen an interval between lead terminals 5 and 6, and there is such a merit that balance after mounting becomes better.
As shown in
It is preferable that parasitic capacitance, which occurs between lead terminals 5, 6, is set in the range of 0.1 pF through 5.0 pF. When parasitic capacitance is larger than 5.0 pF, capacitance fluctuation becomes very large on the occasion when an electronic component is configured. To make it smaller than 0.1 pF comes up with difficulty in manufacturing. It is also possible to trim away lead terminals 5, 6 according to need, and to make an ex-post adjustment of its parasitic capacitance.
By making lead terminals 5, 6 in an approximately identical shape, it is possible to reduce the number of components, so that productivity is improved, and to pull out lead terminals 5, 6 from approximately the same height in armoring material 8, and to pull out portions which are of approximately the same length, so that it is possible to manufacture electronic components with good symmetry.
Armoring material 8 will be described.
Armoring material 8 is, as indicated in
As armoring material 8, epoxy resin such as a opt-cresol-novolac series, a biphenyl series, and pentadiene series is preferably used.
By setting a minimum value of an interval between a surface of armoring material 8 and a surface of multilayer type capacitor 1 (in other words, the thinnest wall thickness of armoring material 8) to 0.1 mm or more, it is possible to improve an outer skin withstand voltage.
By projecting portions, where lead terminals 5, 6 of armoring material 8 are pulled out, more than other portions, it is possible to strengthen roots of pull-out portions of lead terminals 5, 6. By this, it becomes easy to prevent bending etc. of lead terminals 5, 6, and interfusion of moisture from an outside.
One example of a manufacturing method of electronic component 7 will be described here.
Two element bodies, in each of which lead terminals 5, 6 are connected to two multilayer type capacitors 1, are aligned, and multilayer type capacitors 1 and a part of lead terminals 5, 6 are covered by use of a molding machine. Then, portions of lead terminals 5, 6, which are pulled out from armoring material 8, are folded back as shown in
As shown in
Capacitor 1 shown in
By use of
Multilayer type capacitor 1 represented in
Because of existence of chamfer 10, it becomes easy to fill armoring material 8 in opposed region 9. Barrier due to the corner part is reduced, and it becomes easy for resin, which configures armoring material 8, to enter into opposed region 9. On the opposed surface of multilayer type capacitor 1 in the vicinity of the corner parts, the armoring material is floated from the opposed surface, and it is possible to suppress occurrence of pinholes due to insufficient filling of armoring material 8.
Chamfer 10 preferably has its curvature radius of 0.05 mm or more. When a curvature radius of chamfer 10 is smaller than 0.05 mm, a curb of a corner part which is made by chamfer 10 takes the form of an acute angle, and it becomes insufficient as the guiding part for filling armoring material 8 in opposed region 9.
By use of
Non-parallel part 11 is defined in such a manner that opposed surfaces of multilayer type capacitor 1 are not in parallel each other. As represented in
As shown in
Even if a shape of cross section of multilayer type capacitor 1 is not trapezoid, non-parallel parts 11 are to be formed on the opposed surfaces, if a non-orthogonal portion exists on at least one of the corner parts in a shape of cross section of multilayer type capacitor 1. At this time, it is fine if non-parallel parts 1 exist only on the opposed surface. Chamfer 10 may be further combined with the corner part which is formed at non-parallel part 11, which has a further advantage.
By use of
Arc parts 12 are of such things that opposed surfaces of two multilayer type capacitors 1 are of arc shapes. Two multilayer type capacitors 1 face to each other by arc parts 12, and thereby, in opposed region 9, reduced are barriers due to corner parts in a upper side and a lower side which become entrances of armoring material 8. By a smooth curved line of arc part 12, armoring material 8 enters into opposed region 9 slowly, and a sufficient amount of armoring material 8 is filled. Since there is no hang-up etc. of armoring material 8 due to the corner parts, a thin density region etc. are difficult to be formed, and since it is also possible to sufficiently reduce occurrence of pinholes, a withstand voltage between multilayer type capacitors 1 is heightened, and electric field leakage etc. are suppressed. Arc part 12 may be disposed on a non-opposed surface as well as the opposed surface. By this, there is such a merit that crashproof of multilayer type capacitor 1 is heightened more. Arc part 12 may be disposed across entirety of the opposed surface, and may be disposed only on its portion. In this case, it is possible to avoid insufficient filling due to existence of the corner part at an entrance position of armoring material 8 such as a upper side and a lower side of opposed region 9, in the same manner as non-parallel part 11.
By use of
Opposed distance 13 of two multilayer type capacitors 1 is a distance between opposed surfaces. In a case that opposed distance 13 is very small, there is such a problem that a filling amount of armoring material 8 becomes insufficient in opposed region 9, but if it is set to 0.1 mm or more, problems such as a withstand voltage are resolved.
As shown in
By defining opposed distance 13 as 0.1 mm or more, in this manner, a filling amount of armoring material 8 in opposed region 9 becomes sufficient, and improvement of a withstand voltage and prevention of electric field leakage are realized.
As above, even in such a case that, on the opposed surface between multilayer type capacitors 1, the guiding part such as chamfer 10, non-parallel part 11, and arc part 12 is formed, and its opposed distance 13 is defined, and elements starting with two multilayer type capacitors 1 are disposed and molded with one armoring material 8, and a small size electronic component is made, it is possible to suppress performance fluctuation, such as improvement of withstand voltage and prevention of electric field leakage, and to improve endurance, without disturbing miniaturization.
It was so far explained as to a case in which two multilayer type capacitors 1 are disposed, but they may be three or more, and in this case, by taking the same configuration in respective opposed regions 9, reduction of performance fluctuation, improvement of endurance, facilitation of miniaturization are to be realized.
Much the same is true on any one of other electric elements such as a resistor and a normal capacitor, an inductor, a filer, other than multilayer type capacitor 1.
With regard to such matters that it is very effective that chamfer 10 is formed, and a curvature radius of this chamfer 10 is 0.05 mm or more, and it is very effective that opposed distance 13 is set to 0.1 mm or more, it will be described on the basis of an experimental result.
A horizontal axis of
In
In
A horizontal axis indicates the opposed distance of multilayer type capacitors 1, and a vertical axis indicates an occurrence rate of pinholes. As apparent from the graph, even if the guiding part such as chamfer 10 and non-parallel part 11 is not disposed, if opposed distance 13 is 0.1 mm or more, the occurrence rate of pinholes becomes nearly 0%, and sufficient performance is to be provided. In the same manner, even in a case that the guiding part is formed, if opposed distance 13 is 0.1 mm or more, the occurrence rate of pinholes is to be suppressed to nearly 0%. In the case that non-parallel part 11 and chamfer 10 are disposed, it is found that, even if opposed distance 13 is less than 0.1 mm, the pinhole occurrence rate is suppressed to a lower value.
By setting the opposed distance to 0.1 mm, and further disposing chamfer 10 and non-parallel part 11, occurrence of pinholes is suppressed, and endurance to a breakdown voltage and moisture resistance performance are further improved. Definition of the opposed distance and formation of the guiding part such as the chamfer may be provided individually, and they may be used in combination. The combination provides a further advantage.
Finally, by use of
As apparent from
In contrast to this, as apparent from
These have the same advantages, even in a case that three or more elements are molded in one electronic component 7.
In a case of molding a plurality of multilayer type capacitors 1, capacitance values of respective multilayer type capacitors 1 may be changed. It is preferable to select a necessary capacitance value for each individually, in tune with a characteristic of a device for mounting, and to mold in one armoring material 8. As a matter of course, it is fine that different kinds of elements are molded in such a manner that, among a plurality of elements, a certain element may be multilayer type capacitor 1, and others are normal capacitors.
As shown in
As above, a plurality of elements such as multilayer type capacitor 1 are molded with one armoring material to form one electronic component 7, and thereby, it is possible to realize miniaturization of an electronic component. Since one electronic component 7 is mounted on a circuit substrate by one processing, it is possible to save labor, and to reduce mounting cost. As a matter of course, it contributes to reduction of a mounting area. In a case that a plurality of elements are laid out and molded in this manner, by defining an opposed distance between elements, or by disposing a guiding part such as a chamfer, non-parallel part 11, and arc part 12, which makes it easy to fill an armoring material in an opposed region, filling in the opposed region becomes sufficient, and endurance such as a withstand voltage between elements and a moisture resistance property is improved, and performance fluctuation of electronic component 7 is reduced.
It is also preferable to form a composite component, by having an inductor, a capacitor and so on mixed in one armoring material 8 and molding them. The above-described configurations and advantages are particularly useful in a high withstand voltage electronic component in which a high withstand voltage is required.
This invention is an electronic component which has a plurality of elements, a pair of terminal parts which are disposed on the element, and an armoring material which covers the elements and a part of the terminal parts, and it is possible to mount a plurality of electronic components all at once, by such a configuration that the plurality of elements are disposed in the armoring material with predetermined intervals and guiding parts of the armoring material toward an opposed region of the elements are disposed on an opposed surface between the elements, and by such a configuration that a plurality of elements, in particular, multilayer type capacitors are molded in one armoring material and terminals are pulled out to outside, and it is applicable to an application which requires reduction of mounting procedures, and reduction of mounting cost.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2003-413000 | Dec 2003 | JP | national |
| 2004-126627 | Apr 2004 | JP | national |
