JP2005072142A - Wound coil component - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To suppress the leakage of flux to the top face side of a wound coil component 1 small when mounting the wound coil component 1 on a circuit board. <P>SOLUTION: A winding 5 is wound around the winding core 3 of a core member 2 to form the wound coil component 1. Flange parts 4 (4A and 4B) on both sides of the winding core 3 have such a shape as to hang over laterally and on the bottom face side but not hang over on the top face side when the wound coil component 1 is mounted on the circuit board 7. The top face-sides of the flange parts 4 (4A and 4B) are so formed as to be flush with a plate surface on the top face side of the plate-like winding core 3 or lower than that. A magnetic path of magnetic flux generated by the coil consisting of the winding wire 5 is regulated by the particular shape of the flange parts 4, and the magnetic path is hardly formed on the top face side of the winding core 3, resulting in suppressing the leakage of flux to the top face side small. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a wound coil component formed by winding a winding around a core winding portion of a core member made of a magnetic material.

  FIG. 7 shows a schematic side view of an example of a wound coil component (see, for example, Patent Document 1). The winding coil component 30 includes a core member 31 made of a magnetic material and a winding 32. The core member 31 includes a core core portion 33 around which a winding 32 is formed, and flange portions 34 (34a, 34b) provided at both ends of the core core portion 33, respectively. Yes.

  Electrodes 35 (35a, 35b) are respectively formed on the bottom surfaces of the flange portions 34a, 34b shown in FIG. One end of the winding 32 wound around the core core 33 is connected to the electrode 35a, and the other end of the winding 32 is connected to the electrode 35b. The wound coil component 30 is mounted on the circuit board 36 in such a posture that the electrodes 35a, 35b of the flange portions 34a, 34b can be connected to the circuit board 36.

  The winding coil component 30 is formed with a coating material 37 over the entire surface of the portion that becomes the top surface side when mounted on the circuit board 36 as described above.

Japanese Patent Laid-Open No. 10-32438

  In the wound coil component 30 shown in FIG. 7, the magnetic flux generated by the coil formed by winding the winding 32 around the core core portion 33 is, for example, as shown by the arrow α in FIG. 7. From the portion 33, the flange portion 34 a on one end side of the core core portion 33, the bottom surface side of the coating material 37 or the core core portion 33, or the lateral side of the core core portion 33, and the core core portion 33 A magnetic path that passes through the flange portion 34b on the other end side and returns to the core core portion 33 is formed.

  By the way, the magnetic flux that has passed through the projecting portion from the coil core portion 33 to the top surface side of the flange portion 34a toward the top surface side is changed in the direction from the top surface side to the flange surface on the top surface side of the flange portion 34a. It changes to the direction which goes to the part 34b. This magnetic flux changes its direction, and a part of the magnetic flux cannot change its direction and leaks from the coiled coil component 30 to the top surface side as shown by the dotted line β in FIG. Such leakage magnetic flux toward the top surface causes the following problems.

  For example, in a state where the winding coil component 30 is mounted on a circuit board and incorporated in a circuit, other components and signal lines through which high-frequency signals flow are arranged around the winding coil component 30. There are many. The magnetic flux leaking from the coiled coil component 30 to the top surface side adversely affects the operation of the peripheral components, and causes problems such as adding noise to the signal flowing through the signal line. There is a fear.

  In particular, as the size and height of a device in which the wound coil component 30 is incorporated is inevitably increased, the mounting density of the components is inevitably increased, and the winding coil component 30 and the surrounding components and signal lines are reduced. Since the interval between them becomes narrow, the problem caused by the leakage magnetic flux to the top surface side of the wound coil component 30 becomes large.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a wound coil component capable of suppressing leakage magnetic flux toward the top surface.

  In order to achieve the above object, the present invention has the following configuration as means for solving the above problems. That is, the present invention relates to a winding coil component having a core member made of a magnetic material and a winding wound around a core core portion formed between both ends of the core member. The core winding part of the core is formed in a plate shape, and the winding coil component is a horizontal type winding that is installed on the surface of the circuit board with the plate surface of the plate-like core winding part along the circuit board. It is made up of wire coil parts, and on both ends of the core core part, when the coiled coil parts are installed on the circuit board, they do not protrude on the top side but protrude on the bottom side and the side. A flange portion is provided, and the top surface side of the flange portion is formed flush with the plate surface on the top surface side of the core core portion or at a lower position than the plate surface on the top surface side of the core core portion. It is characterized by having.

  In addition, the present invention is such that the top surface side of the core member composed of the core core portion and the flange portions on both ends thereof is covered with resin over the entire surface, or the resin covering the top surface side of the core member. Is also characterized by containing a magnetic material.

  According to the present invention, in a state in which the wound coil component is installed on the circuit board, the flange portions on both ends of the core core portion do not protrude on the top surface side, but protrude on the bottom surface side and the lateral side. Thus, the top surface side of the flange portion is formed flush with the plate surface on the top surface side of the core core portion, or at a lower position than the plate surface on the top surface side of the core core portion. Thus, in this invention, since the flange portion has a unique shape, the magnetic flux generated by the coil formed by winding the core core portion is regulated by the shape of the flange portion. The magnetic path as shown below is configured.

  That is, the magnetic flux is directed from the core core portion to the flange portion on one side, and when reaching the flange portion, the magnetic resistance on the top surface side is large because the flange portion does not protrude on the top surface side. On the other hand, since the flange portion protrudes from the bottom side and the side, and the magnetic resistance on the bottom side and the side is small, the direction of the magnetic flux is changed in the protruding direction (bottom side direction or side direction) of the flange portion. Pass through the flange. That is, the magnetic flux hardly progresses to the top surface side where the flange portion does not project, and almost all of the magnetic flux proceeds in the projecting direction (bottom side direction and lateral direction) through the projecting portion of the flange portion. Then, after the magnetic flux passes through the flange portion on one side as described above, the direction is changed to the direction toward the flange portion on the other side, so that the bottom surface side or the lateral side from the core core portion becomes the core core portion. It goes to the flange part on the other side so as to follow, and then returns to the core core part through the flange part on the other side.

  As described above, the magnetic path of the magnetic flux generated by the coil formed by winding the winding around the core core portion, which is regulated by the unique shape of the flange portion, is the plate surface on the top surface side of the core core portion. The magnetic path that is formed in the region below the position and passes through the region on the top surface side of the core winding core is hardly formed.

  For this reason, the magnetic flux leakage to the top surface side of the coiled coil component can be prevented by providing the unique configuration of the present invention. In addition, by providing a structure that covers the entire top surface of the core member with resin (in other words, a structure in which resin is provided on the entire top surface side portion of the wound coil component), leakage to the top surface side is provided. Magnetic flux can be better prevented. More preferably, the resin contains a magnetic material. Thereby, the prevention effect of the leakage magnetic flux to the top | upper surface side by resin can be heightened.

  In this way, leakage magnetic flux from the top side of the winding coil component can be prevented, and when the winding coil component is mounted on the circuit board, the peripheral components and signal lines are adversely affected by the leakage magnetic flux. It is possible to suppress the occurrence of problems such as By the way, there is a wound coil part that promotes the reduction in size and height in accordance with the reduction in size and height of the device. With this coiled coil component, the space between the coiled coil component and its surrounding components and signal lines becomes very narrow due to the small size and low profile of the device. Although there is a concern that the problem of leakage magnetic flux from the surface side will become large, since the leakage magnetic flux from the top surface side of the winding coil component can be suppressed to be extremely small by providing the configuration of the present invention, the winding coil Even if the distance between the component and the peripheral component or signal line becomes narrow, the occurrence of a problem due to the leakage magnetic flux toward the top surface can be suppressed. As described above, the present invention is particularly effective when it is assumed that the interval between the wound coil component and the peripheral component or signal line is narrowed when mounted on the circuit board.

  In addition, by providing a resin on the entire top surface of the winding coil component, the core member and the winding wound around the core winding core portion can be protected, and the durability of the winding coil component can be protected. Can be improved.

  Embodiments according to the present invention will be described below with reference to the drawings.

  FIG. 1A is a schematic perspective view showing an embodiment of a wound coil component according to the present invention, and FIG. 1B is a schematic view of the wound coil component of FIG. A side view is shown, and FIG. 1 (c) shows a schematic view of the wound coil component of FIG. 1 (a) as viewed from the bottom side. The coiled coil component 1 of this embodiment has a core member 2 as shown in the perspective view of FIG. The core member 2 is made of a magnetic material (for example, a magnetic material having a magnetic permeability μ of 200 or more (for example, ferrite)), a plate-shaped core core portion 3, and flanges provided on both ends of the core core portion 3. Part 4 (4A, 4B). The coiled coil component 1 of this embodiment is a thin one having a height Hc of 1.0 mm or less.

  As shown in FIGS. 1A to 1C, a winding 5 is wound around the core core portion 3 of the core member 2. The winding 5 is an insulation coated conductor formed by covering a conductor (for example, copper wire) with an insulator. The winding 5 may be formed in a single layer around the core core part 3 or may be formed in multiple layers. The winding form of the winding 5 is determined by, for example, specifications. Is done. The wire diameter of the winding 5 is determined in consideration of various points such as the size of the winding coil component 1 and the inductance value required for the winding coil component. The numerical value of the wire diameter is not particularly limited, but a specific example of the wire diameter is, for example, a diameter of about 20 μm to 150 μm. Further, the number of the windings 5 wound around the core core part 3 may be one or plural.

  The coiled coil component 1 of this embodiment example has a posture in which the plate-shaped core core portion 3 is parallel to the circuit board 7 (in other words, the plate surface of the core core portion 3 is along the circuit board 7). ) A horizontally placed winding coil component disposed on the surface of the circuit board 7.

  In this embodiment, the flange portions 4 (4A, 4B) of the core member 2 are not projected to the top surface side when the winding coil component 1 is installed on the circuit board 7, and the bottom surface side and the side surface side, respectively. The shape is overhanging. In this embodiment, the top surface side of the flange portion 4 (4A, 4B) is formed flush with the plate surface on the top surface side of the core core portion 3.

  In the coiled coil component 1 of this embodiment, the portion of the flange portions 4A and 4B that protrudes from the bottom surface functions as a leg of the coiled coil component 1 and is disposed on the circuit board 7. In this embodiment, the inner corners on the bottom side of the flange portions 4A and 4B are cut to form a tapered surface C (see FIG. 1B). Alternatively, as shown in FIG. 4, the inner corners on the bottom side of the flange portions 4A and 4B may be rounded to form a curved surface R. As described above, the inner corner portion on the bottom side of the flange portions 4A and 4B is formed as a tapered surface C or a curved surface R, and the bottom side of the flange portions 4A and 4B is slightly narrowed, whereby the core core portion 3 is bent. The stress caused by can be released. Thereby, the intensity | strength of the winding coil component 1 with respect to the bending of the core winding core part 3 can be strengthened. Of course, the inclination of the cut surface C and the curvature of the curved surface R at the inner corner on the bottom side of the flange portion 4 (4A, 4B) are the contact area between the flange portion 4 and the circuit board 7, and the strength of the flange portion 4. The numerical value is not limited, and is designed so as to increase the strength of the coiled coil component 1 with respect to the bending of the core winding core 3.

  In this embodiment, as shown in FIGS. 3A to 3C, the electrodes 8 (8A, 8B) are formed so as to cover the bottom side surfaces of the flange portions 4A, 4B. A winding start portion of the winding 5 is joined to one side of these electrodes 8A and 8B (here, electrode 8A for convenience), and the winding start portion of the winding 5 is electrically connected to the electrode 8A. (See FIG. 1C). Further, the winding end portion of the winding 5 is joined to the electrode 8 (8B) on the other side in the same manner as described above, and the winding end portion of the winding 5 is electrically connected to the electrode 8B. For example, electrode pads are respectively formed at the setting positions of the flange portions 4A and 4B on the circuit board 7, and the flange portions 4A and 4B are respectively set at the setting positions of the circuit board 7. By joining via solder, each electrode 8 (8A, 8B) of the flange portions 4A, 4B is connected to an electrode pad on the circuit board 7 side. Thereby, the winding 5 can be electrically connected to the circuit formed on the circuit board 7 via the electrode 8 and the electrode pad on the circuit board 7 side.

  Although the configuration of the electrode 8 is not particularly limited, an example of the electrode 8 will be described here. For example, the electrode 8 has a multilayer structure. That is, an underlying conductor layer such as Ag or Cu is formed on the bottom side surface of the flange portion 4. For example, the base conductor layer is formed by applying a paste-like conductor on the bottom side surface of the flange portion 4 by a technique such as dipping or printing, and then baking the paste portion at a high temperature of, for example, 700 to 1000 ° C. 4 is laminated on the bottom side surface. Thus, by laminating and forming the underlying conductor layer by baking, the bonding between the bottom side surface of the flange portion 4 and the underlying conductor layer can be strengthened.

  On the upper side of the underlying conductor layer, for example, a Ni layer, a Cu layer, and a Sn layer are sequentially stacked by a technique such as electrolytic barrel plating. As a specific example of the thickness of each layer, for example, the thickness of the Ni layer is about 1 μm to 3 μm, the thickness of the Cu layer is about 2 μm to 6 μm, and the thickness of the Sn layer is about 5 μm to 25 μm. is there. The Ni layer is heat resistant to the melting temperature of the solder for joining the electrode 8 and the electrode pad on the circuit board 7 side, for example. Further, the Cu layer can enhance the biting property of the conductive wire (for example, copper wire) of the winding 5 with respect to the solder. Furthermore, the Sn layer can increase the bonding strength between the winding (copper wire) 5 and the electrode 8. In addition, the conductor layer laminated | stacked on the upper side of a base conductor layer is not restricted to the above-mentioned structure. For example, the conductor layer may be formed by stacking a Ni layer, a Cu layer, and a Sn layer in an order different from the above. In the above example, the conductor layer has a three-layer structure, but may have a single-layer structure, a two-layer structure, or a multilayer structure of four or more layers. Furthermore, the conductor layer may include an alloy layer made of a plurality of types of metals. Furthermore, the conductor layer may be formed by a technique other than plating.

  For example, ends (winding start portion and winding end portion) of the winding 5 are joined to the electrode 8 using a technique such as thermocompression bonding. When the end portion of the winding 5 and the electrode 8 are joined by thermocompression bonding, the Sn layer of the uppermost layer of the electrode 8 is melted by the heat, and a part or all of the end portion of the winding 5 is the Sn layer. Therefore, the bonding area between the electrode 8 and the winding 5 can be increased, and the bonding strength between the electrode 8 and the winding 5 can be increased. Further, as shown in FIG. 1C, the electrode 8 and the winding 5 can be arranged by inclining the end of the winding 5 with respect to the electrode 8 (for example, θ = 10 ° to 70 °). Therefore, the bonding strength between the electrode 8 and the winding 5 can be further increased.

In this embodiment, as shown in FIG. 3 (b), the height H ₈ of the upper end position of the electrode 8 when the bottom surface position of the flange portion 4 is used as the reference position is the bottom surface position of the flange portion 4. It is lower than the height H ₃ of the position of the bottom face of the core core portion 3 against. Thereby, since the range of the electrode 8 which covers the flange part 4 can be suppressed small, the loss by an eddy current can be reduced.

In this embodiment, the top surface side of the core core portion 3 around which the winding 5 is wound and the flange portions 4A and 4B on both ends thereof are covered with the resin 10 over the entire surface. The core member 2 and the winding 5 can be protected by the resin 10. Although the kind of resin which covers this top | upper surface side is not specifically limited, For example, an epoxy-type resin can be mentioned. Further, the thickness D _{10 of the} resin 10 is appropriately determined in consideration of, for example, the height limit dimension of the wound coil component 1 determined by specifications and the like and the height D ₂ of the core member ₂ (see FIG. 2). Although the numerical value is not limited, for example, the height Hc of the wound coil component 1 is 1.0 mm or less and the thickness D ₂ of the core member 2 is shown. Is designed to be 0.8 mm or less, the thickness D _{10 of the} resin 10 is set to about 0.2 mm.

  In this embodiment, the resin 10 contains a magnetic material (magnetic powder). The content of the magnetic powder with respect to the resin 10 is set in consideration of various points such as manufacturing problems and is not particularly limited. For example, the content of the magnetic powder with respect to the resin 10 is 20%. About 70%. By setting it as such a content rate, the effective magnetic permeability of the winding coil component 1 whole becomes high. As a result, the number of turns of the winding 5 necessary for the winding coil component 1 to have the set inductance value can be reduced, and the resistance Rdc to the direct current of the winding 5 can be reduced. Thereby, it becomes possible to suppress the conduction loss of the wound coil component 1. Moreover, the amount of magnetic flux leakage can be suppressed by increasing the content of magnetic powder in the resin 10.

  The resin 10 can be formed on the top surface side portion of the core member 2 by a technique such as dipping or printing. By using a coating technique such as a dip method or printing, the resin 10 can be selectively formed only on the top surface side portion of the core member 2. For this reason, for example, it can prevent that a part of resin 10 which is an insulator is formed on the electrode 8 on the bottom surface side of the flange portion 4. Thereby, the conduction | electrical_connection defect of the coil component 1 and the circuit board 7 can be avoided. That is, when a part of the resin 10 adheres to the electrode 8, the conductivity of the electrode 8 deteriorates due to the attached resin, and a conduction failure between the wound coil component 1 and the circuit board 7 is likely to occur. On the other hand, as described above, it is possible to prevent a part of the resin 10 from adhering to the electrode 8, thereby avoiding the problem of poor conduction between the wound coil component 1 and the circuit board 7.

  The winding coil component 1 of this embodiment is configured as described above. In the wound coil component 1 according to this embodiment, the flange portions 4A and 4B of the core member 2 do not protrude from the top surface side of the core winding core portion 3 but protrude from the bottom surface and the side. ing. For this reason, the magnetic flux generated by the coil formed by winding the winding 5 around the core core portion 3 is regulated by the specific shape of the flange portion 4 as indicated by an arrow α in FIG. Configure the magnetic path. That is, the magnetic flux from the core core portion 3 to the flange portion 4A changes the direction of the magnetic flux from the direction along the core core portion 3 to the projecting direction of the flange portion 4A (that is, the bottom side direction and the lateral direction). . That is, the magnetic flux hardly goes to the top side.

  Then, after the magnetic flux passes through the flange portion 4A, the direction is changed in the direction toward the flange portion 4B so that the bottom side or the lateral side of the core core portion 3 (winding 5) is along the core core portion 3. To the flange portion 4B. Then, it returns to the core core part 3 through the flange part 4B.

  Thus, the magnetic flux based on the coil of the winding 5 is regulated by the shape of the flange portion 4, and forms a magnetic path biased to a region below the plate surface position on the top surface side of the core core portion 3, A magnetic path is hardly formed in the region on the top surface side of the core winding core portion 3. Thereby, the leakage magnetic flux from the winding coil component 1 to the top | upper surface side can be suppressed very small. In particular, in this embodiment, since the resin 10 containing a magnetic material is formed on the top surface side portion of the wound coil component 1, for example, even if the magnetic flux is directed from the flange portion 4A to the top surface side. 1 (b), the magnetic flux forms a magnetic path that passes through the resin 10 having a small magnetic resistance, passes through the flange portion 4B, and returns to the core core portion 3. The magnetic flux leaking from the component 1 to the top surface side can be more reliably reduced.

  The inventor has confirmed through experiments the effect of preventing leakage magnetic flux toward the top surface by providing the configuration of this embodiment. In the experiment, a winding coil part 1 having a specific configuration in this embodiment was prepared, and a comparative sample for comparison with the winding coil part 1 was prepared. This comparative sample has a configuration in which the flange portion protrudes not only on the bottom surface side and the side surface but also on the top surface side, and other configurations are the same as the winding coil component 1 of this embodiment example. I have.

  With respect to each of the comparative sample and the wound coil component 1 having the configuration of this embodiment, the amount of leakage magnetic flux toward the top surface was measured. The amount of leakage magnetic flux is as follows: when the copper plate is arranged at a position 0.1 mm away from the coiled coil component 1 (comparative sample) on the top surface side, and when the copper plate is not arranged. The inductance value of (comparative sample) was measured, and the rate of change of the inductance value with and without the copper plate relative to the inductance value with and without the copper plate was determined as the amount of magnetic flux leakage.

  As a result of measuring the leakage magnetic flux amount, the change amount of the inductance value in the comparative sample was 36.5%, whereas in the wound coil component 1 having the configuration of this embodiment, the change in the inductance value was The amount was 18.0%. That is, the amount of change in the inductance value in the wound coil component 1 of this embodiment is about ½ of the amount of change in the inductance value of the comparative sample.

  The amount of change in the inductance value due to the presence / absence of the copper plate proximity arrangement increases as the amount of magnetic flux leakage to the top surface increases. In other words, as the amount of magnetic flux leaked to the top surface side decreases, the amount of change in inductance value due to the presence or absence of the copper plate proximity decreases, so as shown in the experimental results, in this embodiment example, By providing a unique configuration (that is, a configuration in which the flange portion 4 does not project to the top surface side), the leakage magnetic flux to the top surface side than that having a configuration in which the flange portion 4 projects to the top surface side. The amount can be reduced.

  In this embodiment, the magnetic path portion between the bottom sides of the flange portions 4A and 4B passes through the space and does not pass through the magnetic material. Therefore, the magnetic path of the magnetic flux generated by the coil of the winding 5 is not opened. It becomes a road. For this reason, the current saturation characteristic of the winding coil component 1 can be improved as compared with the case where the magnetic path of the magnetic flux generated by the coil formed by winding the winding 5 around the core winding core portion 3 is a closed magnetic path. it can.

  In addition, this invention is not limited to this embodiment, Various embodiments can be taken. For example, in this embodiment example, the resin 10 is formed only on the top surface side of the core member 2, but for example, as shown in the perspective view of FIG. The resin 10 may be formed so as to cover it.

  Further, in this embodiment example, the top surface side of the flange portions 4A and 4B is formed flush with the plate surface on the top surface side of the core core portion 3, but for example, the core member 2 shown in FIG. As shown in the side view, the top surface side of the flange portions 4 </ b> A and 4 </ b> B may be formed at a position lower than the plate surface on the top surface side of the core core portion 3.

  Furthermore, in this embodiment, the resin 10 contains a magnetic material (magnetic powder). However, for example, even if the resin 10 does not contain a magnetic material, leakage flux to the top surface side can be suppressed. In some cases, the resin 10 may not contain a magnetic material.

  Further, in this embodiment, a cut surface C or a curved surface R is formed at the inner corner on the bottom side of the flange portion 4 to increase the strength of the wound coil component 1 due to the bending of the core core portion 3. However, there is little concern about the strength deterioration of the winding coil component 1 due to the bending of the core winding core part 3, or the strength deterioration of the winding coil component 1 can be avoided by other means. Alternatively, the cut surface C or the curved surface R may not be formed at the inner corner on the bottom side of the flange portion 4.

  Further, in this embodiment, the wound coil component 1 has a height Hc of 1.0 mm or less, but the present invention is also applicable to a wound coil component having a height Hc higher than 1.0 mm. It can be applied.

It is a figure for demonstrating the example of 1 form of the winding coil component which concerns on this invention. It is the model figure of the core member which extracted the core member from the winding coil components of FIG. 1, and was shown typically. It is a figure for demonstrating the state which formed the electrode in the core member of FIG. It is a figure for demonstrating the other example of a form of the flange part of a core member. It is the typical perspective view showing other examples of embodiments of winding coil parts. It is the side view of the core member which showed the other example of a core member typically. It is a figure for demonstrating one of the winding coil components described in patent document 1. FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Coil part 2 Core member 3 Core core part 4 Flange part 5 Winding 10 Resin

Claims (3)

  In a winding coil component having a core member made of a magnetic material and a winding wound around a core core portion formed between both ends of the core member, the core core portion of the core member is The winding coil component is a horizontal type winding coil component that is installed on the surface of the circuit board with the plate surface of the plate-shaped core core portion along the circuit board. In addition, on both end sides of the core core portion, flange portions are provided that protrude to the bottom side and the lateral side without protruding to the top surface side when the coiled coil components are installed on the circuit board, The top surface side of the flange portion is flush with the top surface side plate surface of the core core portion, or is formed at a lower position than the top surface side plate surface of the core core portion. Winding coil parts.   2. The wound coil component according to claim 1, wherein the top surface side of the core member comprising the core winding core portion and the flange portions at both ends thereof is covered with resin over the entire surface.   3. The wound coil component according to claim 2, wherein the resin covering the top surface side of the core member contains a magnetic material.

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