CN1220472A

CN1220472A - Mounting coil parts on surface

Info

Publication number: CN1220472A
Application number: CN98111704A
Authority: CN
Inventors: 常见昌义
Original assignee: Taiyo Yuden Co Ltd
Current assignee: Taiyo Yuden Co Ltd
Priority date: 1997-12-17
Filing date: 1998-12-17
Publication date: 1999-06-23
Anticipated expiration: 2018-12-17
Also published as: TW403919B; KR19990063122A; CN1143327C; JP3554209B2; JPH11238634A; KR100322514B1

Abstract

The invention provides a surface mounting type coil component with one magnetic core, 2-4 electrode layers and coils. The magnetic core has a flat wiring core part in which the ratio of a thickness dimension to a width dimension is <=1/3 and collar parts extended integrally with the winding core part on both the lengthwise direction ends of the winding core part. The electrode layers are arranged around a peripheral surface including at least height direction side faces of the collar parts of the core and separated from each other. The coil wound around the wiring core part of the core and conductively fixing its both end parts to the electrode layer parts of the side faces which are obliquely derived to the side faces by thermocompression bonding.

Description

Mounting coil parts on surface

The present invention relates to be adapted to be mounted within the extra-thin surface-mounted coil component on the hybrid integrated circuits such as DC-to-DC (DC-DC) transducer.

In recent years, be tending towards light, thin and short and small along with what carry e-machine such as information terminal, the electronic components such as electric capacity, transistor, transformer, integrated circuit in unified module loop such as DC-DC transducer will be constituted, be integrated on the assisting base plate, the installation method that the so-called hybrid integrated circuit that utilizes the surface to install is installed on the main substrate is used widely.

For the single electronic component of above-mentioned hybrid integrated circuit, require to accomplish small-sized, size thin (highly little) certainly, particularly for the big coil component of height dimension (transformer, choking-winding etc.), require to reduce height especially.

For example, structure as the surface installing type transformer of typical mounting coil parts on surface, be generally primary winding and secondary coil respectively on resinous coil rack, on the side or bottom surface of coil rack, load onto the support lead terminal, utilize methods such as soldering again, two ends and the aforesaid frame lead terminal of primary winding and secondary coil are fixed, make its conduction, then magnetic core is embedded in the coil rack.Yet this puts from using coil rack, and it highly is limited reducing, and minimum height dimension is also about 3mm.

As small-sized and highly little structure, just like the product of the transformer 10 of surface installing type such shown in the longitudinal section of Fig. 6.It is will the lead of insulation sheath be arranged, directly be wound on by the volume core segment 1 that has saved coil rack and with this volume core segment integratedly, be located at the flange 2 at the length direction two ends of this lane core segment 1, on one's body 4 of the 3 vertical drum type ferrite magnetic cores that constitute, form coil 5, then this end winding and tiny plate shaped lead terminal 6 solderings are formed together.This terminal 6 is to make being contained in a metallic plate drawing on the flange 3.

In addition, be depicted as the transformer 20 of a surface installing type as the longitudinal section of Fig. 7.It need not be above-mentioned lead terminal 6, but directly the glue of conduction is printed on the bottom surface and periphery surface thereof of a flange 3 of vertical drum type ferrite magnetic core 4 ', dispose the electrode layer 8 of a set again, end with aforementioned coil 5, by the derivation groove that does not illustrate among the figure, fixing with former electrodes layer 8, make its conduction.

And for example the stereogram of Fig. 8 is depicted as the product of surface installing type transformer 30.It is to utilize method of printing, be arranged on the flange 12 of the FERRITE CORE 15 of level with being directly installed on electrode layer 21 on the magnetic core, on 13 the

end face

16,17 and

bottom surface

18,19, then, to be wound on the end of the coil 22 on the core segment 11,, be fixed on the end face 15 of aforementioned each electrode layer 21 by the soldering welding, on 17, make its conduction.This horizontal FERRITE CORE 15 is that the

flange

12,13 with rectangle forms with the two ends, the left and right sides that volume core segment 11 integrally is located at the lane core segment 11 of the Nogata bodily form that dots.

At present, using the surface installing type transformer 20 of FERRITE CORE 4 ' of the aforementioned vertical drum type of general height H=1.6mm shown in Figure 7, is the mounting coil parts on surface of the height dimension minimum after highly reducing.

But, use the structure of the surface installing type transformer 20 of aforementioned vertical drum type ferrite magnetic core 4 ' shown in Figure 7 to reach the limit that reduces height, and state before use in the surface installing type transformer 30 of horizontal FERRITE CORE 15 of Fig. 8, the end of coil 22 is to the difficulty especially of drawing of electrode layer 21, and, the conduction standing part of the protuberance that coil extension or soldering welding causes increases the overall dimension of product, therefore will accomplish small-sized and height dimension has some problems for a short time.

In addition, when using by the soldering welding method, fixed coil end and when making the method for its conduction, the flange 12 of the conduction standing part of

electrode layer

21,13 parts are than broad, and the heating during welding can be passed to volume core segment 11, therefore are subjected to reducing the influences such as insulating properties of coil 22 easily.

Again, in hybrid integrated circuit, when the surface installing type transformer 30 that will use above-mentioned horizontal FERRITE CORE 15 was installed on the assisting base plate, leakage magnetic flux acted on the wiring graph with assisting base plate installed surface facing surfaces, exists the problem that inductance value is reduced significantly.In addition, go back the insulation that special requirement guarantee the wiring graph of electrode layer 21 and main substrate really.

The present invention proposes in view of the above problems, and it has used the flat partially fuse of the level that did not in the past have, and the conduction standing part to coil and electrode layer improves simultaneously, has realized the littler structure of mounting coil parts on surface height.

The present invention:

(1) in order to achieve the above object, the invention provides mounting coil parts on surface, this part has a magnetic core, 2～4 electrode layers and coil.The ratio (t/w) that this magnetic core has gauge t and a width dimensions w integrally is arranged on the flange at the two ends of this volume core segment length direction at the flat volume core segment below 1/3 with this volume core segment.These 2～4 electrode layers are configured in the flange that contains aforementioned magnetic core is on the periphery surface of side of short transverse at least, and separates each other.This coil is wound on the volume core segment of aforementioned magnetic core, simultaneously, two end, by thermal pressure welding method with fix from the electrode layer of this side that the side updip of said flange is tiltedly drawn respectively, and make its conduction.

(2) in order to achieve the above object, the invention provides mounting coil parts on surface, wherein, aforementioned coil be the end of reel finishing a side at least, fix with the prolongation of the aforementioned lane core segment gauge of the electrode layer of the flange side of aforementioned magnetic core, and conduction.

(3) in order to achieve the above object, the invention provides mounting coil parts on surface, wherein, the flange height size H of aforementioned magnetic core is below 1.6mm, and the diameter of aforementioned coil is between 30 μ m～150 μ m.

(4) in order to achieve the above object, the invention provides mounting coil parts on surface, wherein, the thickness of the electrode layer that is connected with the standing part of aforementioned overhang is below the diameter of aforementioned coil.

(5) in order to achieve the above object, the invention provides mounting coil parts on surface, wherein, the place of volume core segment near the periphery surface of the flange of the aforementioned magnetic core that is provided with the former electrodes layer is provided with the gap area that does not form the former electrodes layer.

(6) in order to achieve the above object, the invention provides mounting coil parts on surface, wherein, the coil stationary of former electrodes layer partly has a width enlarged for 1.5～4.0 times of coil diameters.

(7) in order to achieve the above object, the invention provides mounting coil parts on surface, wherein, electrode layer is located in the groove on the flange side of aforementioned magnetic core, simultaneously, with the fixing part of the former electrodes layer of end winding, is placed in the aforementioned grooves.

(8) in order to achieve the above object, the invention provides mounting coil parts on surface, wherein, on the surface of the installation base plate face of the coil of lane on the core segment of lane, configuration flatly adds the resin bed of one deck magnetic powder.

Mounting coil parts on surface of the present invention, owing to be above-mentioned such formation, it has following effect.

(1) can realize highly being reduced to below the 1.6mm, and be adapted to be mounted within on the hybrid integrated circuit.

(2) can suppress the coil sag that causes by thermo-compressed and outside outstanding.

(3) can obtain utilizing thermo-compressed, the proper range of the coil diameter when making coil and electrode layer conduction fixedly.

(4) overhang can be reliably with the side of magnetic core flange on the electrode layer thermo-compressed.

(5) utilize gap area, can keep being wound on the coil on the core segment and the distance of electrode layer, therefore can keep good insulation performance.

(6) because the standing part of coil has a width enlarged for 1.5～4.0 times in coil straight line, therefore, can guarantee with the thermo-compressed zone of electrode layer enough greatly really, improve and conduct electricity the connection reliability of standing part.

(7) because the conduction standing part is placed in the groove of magnetic core flange side, the conduction standing part can outwards not given prominence to, and therefore, can keep overall dimension constant.

(8) insulating properties of the assisting base plate of main substrate and hybrid integrated circuit improves, and then its fail safe improves.

The present invention is described in detail below in conjunction with accompanying drawing.

Fig. 1 is the stereogram of the outward appearance of expression surface installing type transformer of the present invention;

Fig. 2 is the longitudinal section of the X direction of surface installing type transformer of the present invention;

Fig. 3 is the amplification stereogram of the conduction standing part of the side end face of the flat FERRITE CORE of expression surface installing type transformer of the present invention;

Fig. 4 (a) and Fig. 4 (b) are respectively the end view of amplification of coil conduction standing part of expression FERRITE CORE flange side and the plane graph of amplification;

Fig. 5 is for being installed in surface installing type transformer of the present invention hybrid integrated circuit on the assisting base plate, the longitudinal section of the state of installing on main substrate;

Fig. 6 is the longitudinal section of the existing surface installing type transformer device structure of expression;

Fig. 7 is the longitudinal section of the existing surface installing type transformer device structure of expression;

Fig. 8 is the stereogram of the existing surface installing type transformer device structure of expression.

Describe the embodiment of mounting coil parts on surface of the present invention now in detail according to Fig. 1～Fig. 5.Though, coil component as surface installing type, comprise various parts such as transformer, choking-winding, filter, but because except different with the coil number as the electrode layer number of external connection terminals, all be same structure, therefore, in an embodiment, as the typical case, with a transformer of instruction card surface installation type.

At first, Fig. 1～surface installing type transformer 50 shown in Figure 5 has the ratio (t/w) of the such thickness t of Fig. 4 (a) and Fig. 4 (b) and width w at the flat volume core segment 31 below 1/3,35, four electrode layers 38 of FERRITE CORE and coil 39.This FERRITE CORE 35 has the

flange

32,33 that integrally is arranged on the length direction two ends of this lane core segment 31 shown in Figure 2 with the volume core segment.These four electrode layers 38 are configured in that to contain be on the periphery surface of side 36 of short transverse of

flange

32,33 of aforementioned FERRITE CORE 35 shown in Figure 1 at least, and are spaced from each other.This coil 39 is wound on the volume core segment 31 of aforementioned FERRITE CORE 35, simultaneously, and two end, as shown in Figure 3, utilize thermal pressure welding method,, and make its conduction with the electrode layer part 38 ' from this side 36 that aforementioned flange side 36 updips tiltedly derive is fixing respectively.Figure 1 shows that whole width w is 3.6mm, spool length dimension L is 5.5mm, and height H is the microminiature of 1.2mm and very flat surface installing type transformer.

As mentioned above, because the present invention is so that the coil component miniaturization of surface installing type and reduce it highly as first purpose, for achieving this end, trying hard to make as aforementioned existing embodiment's, when the surface installing type transformer 30 of the FERRITE CORE 15 of usage level is made flat, also should take some to solve the measure of its problem.Here, so-called flat magnetic core of the present invention is defined as the thickness t of volume core segment 31 of the FERRITE CORE 35 that satisfies aforesaid surface installing type transformer 50 and the ratio (t/w) of its width w is the magnetic core of the condition below 1/3.In other words, the flat magnetic core that satisfies above-mentioned flat condition is unexistent in the past, and it is the key that reduces the height of mounting coil parts on surface.

Said structure, compare with the surface installing type transformer 20 that uses existing vertical drum type ferrite magnetic core 4 shown in Figure 7, can adapt to the requirement that reduces height on the structure, and since with the flange 32 of this flat FERRITE CORE 35, the electrode layer part 38 ' of the side 36 of 33 short transverse is to connect with the thermal pressure welding method conduction, therefore, the extension of coil 39 or conduction standing part can not increase the height dimension of product, can be as mentioned above, make highly minimumly, realize height dimension H is suppressed at about 1.2mm and (also height dimension may be made about 0.8mm in the future).

In addition, because the end of coil 39 is to utilize compression bonding method, with volume core segment 31 flange 32 farthest from the coil 39 of reeling; the electrode layer part 38 ' of the side 36 of 33 short transverse is fixing, and makes its conduction, therefore; the heat that reaches volume core segment 31 is few, can protect coil 39.

In the transformer 50 of above-mentioned surface installing type, should note, such shown in Fig. 4 (a), it is characterized by, the lane of coil 39 is positioned at around the conduction standing part of the electrode layer 38 of the end of end on the prolongation of gauge of aforesaid roll core segment 31 of electrode layer 38 of side 36 of this flange 33.Particularly, be placed in the above-mentioned scope of side 36 of flange 33 by conducting electricity standing part, even because thermo-compressed, make the lane that is wound on the coil on the flat volume core segment of magnetic core on the extension of end, have coil to stretch out and relax, the coil ledge that exceeds beyond the height dimension is suppressed, therefore, be difficult to influence the height dimension of coil component, this is its advantage.

In addition, in above-mentioned surface installing type transformer 60, according to present inventor's research, when height dimension H when 1.6mm is following, the diameter of coil 39 is preferably in 30 μ m～150 mu m ranges.Use to surpass the thick coil of above-mentioned scope, needed heat is excessive when thermo-compressed, and the insulating reliability of coil is had adverse effect, if coil is thin, then is difficult to obtain high tensile strength on the conduction standing part of thermo-compressed.

In addition, wish also in above-mentioned surface installing type transformer 50 that the thickness of the electrode layer 38 ' that is connected with the end conduction standing part 41 of coil 39 is below the diameter of aforementioned coil 39.Because, when adopting thermo-compressed, when crimping as the conduction fixing means, the end of coil 39 can be absorbed in the electrode layer 38 ', even in this case, still has bigger thrust effect at end winding, therefore, can keep conducting electricity fixing reliably with electrode layer 38 '.

Secondly, in above-mentioned surface installing type transformer 50, because the FERRITE CORE of usage level 35, the insulating properties of more necessary consideration external circuit figure and coil 39 and the influence of leakage magnetic flux.

In addition, in the surface installing type transformer 50 of Fig. 1, the place of volume core segment 31 at the periphery surface of the flange 32 of the aforementioned FERRITE CORE 35 of fixing electrode layer 38 near printing is provided with the gap area D that is not printing former electrodes layer 38.Because the existence of this gap area D, when the number of turns of coil 39 is many, when reaching the edge of periphery surface of

flange

32,33, still can keep certain distance being arranged with electrode layer 38, therefore can keep good insulation performance.

And for example shown in the amplification stereogram of Fig. 3, because the conduction standing part 41 of the coil 39 of electrode layer 38 has 1.5～4.0 times the width enlarged (width d) for this coil diameter, therefore utilize thermal pressure welding method (for example spot welding), can obtain very high bonding strength.From this point, when height dimension H=1.2mm, enter to the sloped-end of coil 39 on the narrow and small side end face 36 (that is the acute angle that, forms θ=20 °～60 °) with the edge 36a of side end face 36, therefore, the fixed-area that utilizes spot welding method and electrode layer 38 conductions to fix can be bigger.

In addition, in the surface installing type transformer 50 of Fig. 1 and Fig. 3, electroplax layer 38 ' passes through method of printing, be fixed on the flange 32 that is located at this flat FERRITE CORE 35, in the groove 42 on 33 the side 36, simultaneously, the conduction standing part 41 that is connected with the former electrodes layer 38 ' of coil 39 ends also is placed in the aforementioned grooves 42.Like this, conduction standing part 41 is placed in the groove 42 fully, can outer end size from the side not expose, and can correctly determine overall dimension, also can avoid contacting with other electron component.In addition, around the conduction standing part 41, preferably utilize the coverings of using for insulation protection and fixing such as resin.

Here, shown in the longitudinal section of Fig. 5, it is very big to be installed in the danger that the inductance value of the aforementioned surfaces mount type transformer 50 on the assisting base plate 44 of hybrid integrated circuit reduces, and this is because the wiring graph P1 on an opposite side surface of this assisting base plate 44 and the influence of leakage magnetic flux cause.

Therefore, in Fig. 5, as the countermeasure that addresses the above problem, at the assisting base plate 44 of hybrid integrated circuit with installed between the surface of coil 39 of surface installing type transformer 50, pressed from both sides the resin bed 46 (resinous coat that on the surface of coil 39, applies or resinous flat) that one deck adds the magnetic powder.Like this, the adverse effect of leakage magnetic flux can be prevented, coil 39 can be protected simultaneously.In addition; on the surface of the coil by smooth above-mentioned resin bed 46 being arranged on main substrate 45; can between the electronic component of main substrate and wiring graph P2, form insulation protection etc., simultaneously, can also improve the adsorptivity effect when absorption being installed with automatic assembling machine.

Employed various members in above-mentioned surface installing type transformer 50 are described below.

At first, employed core material has no particular limits among the present invention, in fact, can use the Ni-Zn series ferrite, the material of high resistivities such as nickel zinc-copper based ferrite as the material of the FERRITE CORE among the above-mentioned embodiment 35.Its overall dimension when considering ferritic physical strength, can be got, width w=3.6mm, and (height of flange 32,33) H=0.5～1.6mm highly, the height (thickness) of volume core segment 31 is 0.3～0.8mm.Here, width w should be more than 3, better more than 5 to the ratio of the thickness t of lane core segment 31.In addition, length dimension L should suitably design, and in the surface installing type transformer 50 of Fig. 1, probably is 5.5mm.

Electrode layer 38 certainly will contain conducting resinl printing, the sintering of silver powder and frit simply, be fixed on the periphery surface of

flange

32,33 and the end face left-right integratedly after, cut apart with method for sorting such as sandblasts again; But also can fix, also can adopt printing process by duplicating with the method for distinguishing printing.In addition, as required, also can plate electroplating processes such as scolding tin or copper facing on the surface of former electrodes layer 38.In Fig. 5, for the insulation of the wiring graph of main substrate 45, the electrode layer part 38b near the periphery surface of the

flange

32,33 relative with main substrate of main substrate 45 preferably is not set.

From the mounting coil parts on surface of described surface installing type transformer of the present invention 50 beginnings in the above, it highly can be reduced, accomplish that its height H (about now for 1.2mm, can reach about 0.8mm) below the 1.6mm in the future.As shown in Figure 5, it is possible will making the thickness h that surface installing type transformer 50 is installed in the hybrid integrated circuit under the state on the main substrate 45 below the 1.8mm.

In addition, because the height of surface installing type transformer 50 of the present invention is identical with slim integrated circuit height, therefore, under situation about being directly installed on the main substrate 45, can reduce the height of main substrate too.

Claims

1. a mounting coil parts on surface is characterized by, and it has a magnetic core, 2～4 electrode layers and coil; The ratio (t/w) that this magnetic core has thickness t and a width w is located at the flange at the two ends of this volume core segment length direction integratedly at the flat volume core segment below 1/3 with this volume core segment; These 2～4 electrode layers are arranged on that to contain be on the periphery surface of side of aforementioned magnetic core flange height direction at least, and spaced from each other; This coil is wound on the volume core segment of aforementioned magnetic core, and simultaneously, its two ends utilize thermal pressure welding method, fixes with the electrode layer of this side of deriving of tilting in the said flange side respectively, and makes its conduction.

2. mounting coil parts on surface as claimed in claim 1 is characterized by, aforementioned coil be the end of its coiling end at least, fix with the prolongation of the thickness of aforesaid roll core segment on the electrode layer of aforementioned magnetic core flange side, and make its conduction.

3. mounting coil parts on surface as claimed in claim 1 or 2 is characterized by, and the height of aforementioned magnetic core flange is below 1.6mm, and the diameter of aforementioned coil is between 30 μ m～150 μ m.

4. mounting coil parts on surface as claimed in claim 1 or 2 is characterized by, and the thickness of the electrode layer that is connected with the standing part of aforementioned end winding is below aforementioned coil diameter.

5. mounting coil parts on surface as claimed in claim 1 or 2 is characterized by, and the place of volume core segment near the periphery surface of the aforementioned magnetic core flange that is provided with the former electrodes layer is provided with the gap area that does not form the former electrodes layer.

6. mounting coil parts on surface as claimed in claim 1 or 2 is characterized by, and the coil stationary of former electrodes layer partly has the width enlarged for 1.5～4.0 times of coil diameters.

7. mounting coil parts on surface as claimed in claim 1 or 2 is characterized by, and electrode layer is formed in the groove on the side of being located at aforementioned magnetic core flange, simultaneously, also is placed in the aforementioned grooves with the standing part of the former electrodes layer of end winding.

8. mounting coil parts on surface as claimed in claim 1 or 2 is characterized by, and on the surface of the installation base plate face of the coil of lane on the core segment of lane, flatly disposes the resin bed that one deck has added the magnetic powder.