JP4719994B2 - Circuit board and manufacturing method thereof - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a circuit board and a manufacturing method thereof.
[0002]
[Prior art]
There is a circuit board using a lead frame as a circuit board through which a large current flows.
[0003]
That is, in the conventional device in which the printed pattern is formed on the substrate, a large current cannot be passed through the printed pattern, so that a large current can be passed by using a thick lead frame.
[0004]
Specifically, a circuit board using the above lead frame has a structure in which the lead frame is polymerized on a sheet, and both are integrated by heating and pressurizing.
[0005]
In this case, the lead frame is provided with a plurality of conductive patterns. When the heating and pressing are performed, a part of the lower sheet is raised between the conductive patterns to the upper surface of the conductive pattern. The insulation between them is kept.
[0006]
[Problems to be solved by the invention]
A problem in the above conventional example is the insulation distance between the conductive patterns.
[0007]
In other words, a high voltage conductive pattern and a low voltage conductive pattern are confused in the lead frame, and a large insulation distance is required between adjacent high voltage and low voltage conductive patterns, which increases the size of the circuit board. Become.
[0008]
SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to reduce the size of a circuit board.
[0009]
[Means for Solving the Problems]
  And to achieve the purposeBookThe invention of claim 1 is an insulating sheet and polymerized on the sheet.The high-pressure side lead frame and the low-pressure side lead frame that are adjacent to each other with the separation part interposed therebetweenAnd comprisingThe high pressure side lead frame and the low pressure side lead frame are respectivelyIt has a plurality of conductive patterns, and between these conductive patterns, the lower sheet protrudes up to the upper surface of the conductive pattern, and the other conductive pattern is on the upper surface of at least one of the conductive patterns located on both sides of the conductive pattern. The side opposite the patternThe distance between the conductive pattern on the high voltage side and the conductive pattern on the low voltage side where the high voltage side lead frame and the low voltage side lead frame are adjacent to each other is between the adjacent conductive patterns on the high voltage side and adjacent on the low voltage side. Longer than between the conductive patternsIt is a configuration.
[0010]
  With such a configuration, the lower insulating sheet projects between the adjacent conductive patterns up to the upper surface, and on the upper surface of at least one of the conductive patterns located on both sides, the other Since the side facing the conductive pattern is covered, the effective insulation distance between the adjacent conductive patterns is increased. As a result, not only can the short-circuit between these adjacent conductive patterns be prevented, but the adjacent portions are also adjacent. The distance between conductive patterns can be shortened to reduce the sizeAt the same time, the insulation distance between the high pressure side and the low pressure side becomes longer, which is preferable as an insulation measure.
[0012]
  Next, the present inventionClaim 2The circuit board according to claim 1, wherein a recess is formed in the sheet at the separation portion on the high pressure side and the low pressure side of the lead frame, and the recess is formed on the sheet at the separation portion on the high pressure side and the low pressure side of the lead frame. As a result, the creepage distance between the high-pressure side and the low-pressure side becomes long, which is preferable as an insulation measure.
[0013]
  Next, the present inventionClaim 3In this invention, an insulating sheet is provided on one of the front and back surfaces of the lead frame, and the otherFlexibleThe plate is polymerized, and then the three polymers are heated and pressurized, and then the plate isAboveIn a method of manufacturing a circuit board to be peeled from a lead frame,AboveOn the surface on the lead frame side, a recess facing the plate body side from the lead frame is formed in a portion facing the conductive pattern constituting the lead frame, and the recess is a conductive pattern located on both sides of the recess. A method of manufacturing a circuit board that extends to the side surface of at least one plate body, wherein a sheet, a lead frame, and a polymer of a plate body are heated and pressurized to heat the sheet and the sheet is fluidized to form a lead frame. It will penetrate | invade into the recessed part of a board | plate body from between.
[0014]
In this case, since the concave portion of the plate extends to at least one plate surface of the conductive pattern located on both sides of the concave portion, the melt of the sheet penetrates into the concave portion, and one side surface of the conductive pattern has a side surface. Will cover the part.
[0015]
As a result, a part of the sheet exists between the adjacent conductive patterns, and the part of the sheet not only protrudes toward the plate body to be peeled later, but also covers at least a part of the conductive pattern. As a result, the effective insulation distance between adjacent conductive patterns is increased, and as a result, a short circuit between adjacent conductive patterns can be prevented.
[0016]
Also, by forming a recess in the plate body, a part of the sheet can be projected to the plate body side between the conductive patterns, and a part of the side surface of the plate body of the conductive pattern can be covered, so that productivity can be increased. it can.
[0017]
  With that,Since the plate body has flexibility, the sheet does not flow out to the conductive pattern outside the concave portion by being in close contact with the lead frame.
[0018]
In other words, since electronic parts are mounted on the conductive pattern, if even that part is covered with the outflow part of the sheet, this electronic part can not be mounted, or the process of removing the outflow part of the sheet, etc. These are prevented because extra work is required.
[0019]
  nextClaim 4In the invention, the plate body is formed of resin, and a heat transfer body is mixed in the resin.Claim 3In the method of manufacturing a circuit board described in 1., since a heat transfer body is mixed in the plate body, heat can be easily transferred from the plate body side to the lead frame and the sheet, and as a result, the sheet flows smoothly. It becomes possible to make it.
[0021]
  nextClaim 5The invention ofAn insulating sheet is polymerized on one of the front and back surfaces of a lead frame composed of a high-voltage side lead frame and a low-voltage side lead frame arranged with a dummy pattern in between, and a plate is polymerized on the other, and then the three polymers are heated. In the method of manufacturing a circuit board, the plate body is peeled from the lead frame, and then the dummy pattern is removed from the sheet after the lead frame is integrated on the sheet. On the surface facing the lead frame, a portion facing the conductive pattern constituting the lead frame is formed with a concave portion from the lead frame toward the plate body, and the concave portion is electrically conductive located on both sides of the concave portion. A method of manufacturing a circuit board, wherein the circuit board is spread to at least one plate side surface of the patternBecauseAs the sheet fluidizes and enters the recesses of the plate body from between the conductive patterns constituting the lead frame,If the dummy pattern is removed after the sheet and the lead frame are integrated together, the high pressure side and the low pressure side of the lead frame are separated on the sheet, so that sufficient insulation measures can be taken between them.
[0022]
  nextClaim 6In the invention, the dummy pattern is formed as an uncovered portion of the protruding portion of the sheet.Claim 5In the method for manufacturing a circuit board according to the item 1, since the dummy pattern is not covered with a part of the sheet, the dummy pattern is easily peeled off from the sheet.
[0023]
  nextClaim 7According to the present invention, a plurality of conductive patterns are provided on the high-voltage side and the low-voltage side of the lead frame, respectively, and leads having substantially the same first distance are formed between adjacent patterns among these conductive patterns and dummy patterns. Integrate on the sheet using the frame, and place the sheet between each adjacent first distance patternAboveRaise to the top of the conductive pattern, thenTo the aboveRemove dummy patternClaim 5In the method for manufacturing a circuit board according to the above, the insulation distance between the high voltage side and the low voltage side of the lead pattern can be easily ensured by removing the dummy pattern.
[0024]
In addition, when the lead frame and the sheet are integrated, a part of the sheet protrudes upward between adjacent patterns. At this time, the distance between the patterns is the first distance due to the presence of the dummy pattern. Since the sheet and the lead frame polymer are heated and pressed, the amount of the sheet softened and raised between the patterns becomes substantially the same between the patterns.
[0025]
For this reason, there is no variation in the insulation distance between adjacent patterns by pressing the pattern in the horizontal direction due to the difference in the amount of a part of the sheet protruding between the patterns.
[0026]
  nextClaim 8In this invention, the lower surface side of the conductive pattern on the low voltage side and the high voltage side of the lead frame is a rough surface, and the lower surface side of the dummy pattern is a non-rough surface.Claim 6 or 7The circuit board manufacturing method according to claim 1, wherein the lower surface side of the conductive pattern on each of the low-voltage side and the high-voltage side is roughened so that the bonding force with the lower sheet is increased and the conductive pattern is stably arranged. It will be.
[0027]
Further, since the lower surface of the dummy pattern is a non-rough surface, it can be easily removed even after the lead frame and the sheet are integrated.
[0030]
  nextClaim 9According to the invention, a vent is formed in the concave portion of the plate body.Claims 3-8In the method for manufacturing a circuit board according to any one of the above, since the air hole is formed in the concave portion of the plate body, when a part of the sheet flows between the conductive patterns toward the concave portion, The air existing in the portion is discharged from the vent hole, and as a result, a part of the sheet can smoothly flow.
[0031]
  nextClaim 10According to the invention, the bottom surface of the concave portion of the plate body is formed in a dome shape that protrudes to the opposite side of the lead frame, and a vent hole is formed in the center of the dome.Claim 9The method of manufacturing a circuit board according to claim 1, wherein a concave portion of the plate body is formed into a dome shape and a vent hole is formed at a central portion thereof so that a part of the sheet smoothly enters the concave portion of the plate body. Will be.
[0032]
DETAILED DESCRIPTION OF THE INVENTION
An embodiment of the present invention will be described below with reference to the accompanying drawings.
[0033]
In FIG. 1, reference numeral 1 denotes an automobile, and the automobile 1 includes a main body 2 and four tires 3 that support the main body 2. The tire 3 is driven by an engine 4 and a drive motor 5. That is, at the time of starting, it is started by the drive motor 5 and is driven by the engine 4 when the speed reaches a predetermined speed.
[0034]
In order to drive the drive motor 5, a very large voltage is required. In this embodiment, a DC power supply 6 of 300V is provided. The DC motor 6 drives the drive motor 5. The DC power source 6 is converted to 14V by the DC / DC converter 7, thereby charging the DC power source 8 to 14V.
[0035]
The DC power supply 8 drives another load such as the light 9. FIG. 2 shows only the electric circuit portion having the above configuration.
[0036]
As shown in FIG. 2, the direct current power source 6 is connected to a drive motor 5 and a DC / DC converter 7. A generator 10 is driven by the engine 4, and the voltage obtained by the generator 10 charges the DC power supply 6.
[0037]
The 300V DC power supply 6 is connected to a DC / DC converter 7, and on the secondary side, the DC power supply 8 is charged to 14V.
[0038]
FIG. 3 shows a connection portion between the DC / DC converter 7 and the light 9.
[0039]
That is, the current I is supplied from the DC / DC converter 7 to the light 9 via the DC power supply 8.₀When the current flows, a voltage drop always occurs in the line resistance 11.
[0040]
As a result, the DC power supply 8 may not be charged to 14V, and the light 9 may not be supplied with 14V. Therefore, the current I for the light 9 is thus₀When the current flows, it is necessary to increase the voltage of the DC / DC converter 7 to prevent the voltage drop of the DC power supply 8 and the voltage drop of the voltage supplied to the load.
[0041]
Therefore, in this embodiment, the DC / DC converter 7 is configured as shown in FIG.
[0042]
In the DC / DC converter 7, a transformer 14 is provided between the input terminal 12 and the output terminal 13. An opening / closing control means 16 is connected to the primary winding 14 a of the transformer 14 via a switching means 15.
[0043]
A smoothing circuit including a diode 17 and a capacitor 18 is connected to the secondary winding 14 b of the transformer 14. A series body of resistors 19 and 20 is connected to the output terminal 13, and the negative input terminal of the operational amplifier 21 is connected to the connection point.
[0044]
A reference power supply 22 is connected to the positive input of the operational amplifier 21, and the output of the operational amplifier 21 is connected to the switching control means 16.
[0045]
Further, between the secondary winding 14b and the output terminal 13, a current detection means 23 composed of a resistor is connected. The current detection means 23 is composed of a small resistance. However, a voltage is generated by the current that flows even with this small resistor, the voltage is amplified by the amplifier 24, and this is input to the negative input terminal of the operational amplifier 25. A reference power supply 26 is connected to the positive input terminal of the operational amplifier 25.
[0046]
Further, the connection point of the resistors 19 and 20 is connected to the output of the operational amplifier 25 through the resistor 27.
[0047]
In the configuration as described above, as shown in FIG. 3, when the light 9 is connected to the DC power source 8 and this light 9 is driven, in FIG.₀A large current flows. When this large current flows, it is detected by the current detection means 23, amplified by the amplifier 24, and input to the negative input of the operational amplifier 25.
[0048]
Then, the operational amplifier 25 makes a comparison with the reference voltage 26, and a current corresponding to the comparison result is passed through the resistor 27. The current flowing through the resistor 27 is the current I₀That is, the larger the current flowing through the light 9, the greater the current flowing through the resistor 27.
[0049]
Load current I₀Becomes larger, the voltage of the current detecting means 23 becomes larger, which is amplified by the amplifier 24 and supplied to the negative input of the operational amplifier 25.
[0050]
When the difference between the negative input of the operational amplifier 25 and the reference voltage becomes smaller, the output voltage of the operational amplifier 25 becomes lower. As a result, the voltage at the connection point of the resistors 19 and 20 is also lowered, and the voltage at the negative input of the operational amplifier 21 is lowered by the voltage being lowered in this way. When the negative input of the operational amplifier 21 decreases, the output voltage of the operational amplifier 21 increases. When the output voltage of the operational amplifier 21 increases, the current of the photodiode provided for separating the primary side and the secondary side of the transformer 14 in the switching control means 16 is reduced.
[0051]
When the current flowing through the photodiode is reduced, in the PWM control circuit provided in the switching control means 16, the ON time of the switching means 15 is lengthened, thereby increasing the voltage generated in the secondary winding 14b of the transformer 14. Become.
[0052]
As a result, the voltage across the DC power supply 8 in FIG. 3 becomes high, and the voltage drop due to driving the light 9 can be compensated.
[0053]
That is, even in this case, the light 9 can be stably operated.
[0054]
The DC / DC converter 7 shown in FIG. 4 is configured by mounting the various electronic components shown in FIG. 4 on the circuit board 28 shown in FIG.
[0055]
The right side of the circuit board 28 shown in FIG. 5 is a high voltage side 28A, that is, a region where various electronic components on the primary winding 14a side of the transformer 14 of FIG. 4 are mounted, and the left side is a low voltage side 28B. That is, this is an area where various electronic components on the secondary winding 14b side of the transformer 14 of FIG. 4 are mounted.
[0056]
The circuit board 28 is formed by superposing a lead frame 30 on a sheet 29 and pressurizing while heating, and the various electronic components are formed by conductive patterns 28a and 28b on the high voltage side 28A and the low voltage side 28B, respectively. It is mounted on and is in electrical continuity.
[0057]
Note that the outer peripheral frame 30a of the lead frame 30 in FIG. 5 is separated before or after mounting the various electronic components.
[0058]
Further, as shown in FIG. 6, when the sheet 29 and the lead frame 30 are integrated with each other, after the sheets 29 between the adjacent conductive patterns 28a and 28b are raised above the surfaces of the conductive patterns 28a and 28b. This is solidified (this point will be described in detail later with reference to FIGS. 9 and 10).
[0059]
For this reason, there is no left-right displacement between the adjacent conductive patterns 28a and 28b even after the outer peripheral frame 30a of the lead frame 30 is separated.
[0060]
Further, the distance between the adjacent conductive patterns 28a and 28b on the high voltage side 28A and the low voltage side 28B is substantially the same as the first distance Ta as shown in FIGS. On the other hand, the distance between the conductive pattern 28a on the lowest voltage side 28B in the conductive pattern 28a on the high voltage side 28A and the conductive pattern 28b on the highest voltage side 28A in the conductive pattern 28b on the low voltage side 28B is the first distance Ta. The second distance Tb is larger than the second distance Tb.
[0061]
That is, as shown in FIG. 5, the high-pressure side 28A and the low-pressure side 28B are separated into the left and right, and the second distance Tb provided therebetween is between the plurality of conductive patterns 28a and 28b provided on the high-pressure side 28A and the low-pressure side 28B, respectively. If the distance is larger than the first distance Ta, a sufficient insulation distance between the high voltage side 28A and the low voltage side 28B can be taken on the circuit board 28, and sufficient insulation measures can be taken.
[0062]
Further, by separating the high-pressure side 28A and the low-pressure side 28B, in the separated high-pressure side 28A and low-pressure side 28B, the adjacent conductive patterns 28a, 28b separate the high-pressure side 28A and the low-pressure side 28B. Since it suffices to separate the first distance Ta smaller than the distance Tb, the circuit board 28 can be downsized as a whole.
[0063]
Further, as shown in FIG. 6, a recessed portion 31 is formed in the sheet protruding portion between the conductive patterns 28a and 28b on the high-pressure side 28A and the low-pressure side 28B having the second distance Tb, and by providing the recessed portion 31 in this portion. Since the creepage distance between the conductive patterns 28a and 28b on the adjacent high voltage side 28A and low voltage side 28B is further increased, a sufficient insulation measure can be taken.
[0064]
A method for manufacturing the circuit board 28 shown in FIGS. 5 and 6 will be described below.
[0065]
First, the sheet 29 is formed on the releasable film 32 as shown in FIG. As the forming method, a mixture slurry comprising at least an inorganic filler, a thermosetting resin composition and a solvent is prepared and formed on the release film 32 by film formation. As the film forming method, the existing doctor blade method, coater method, and extrusion method can be used. And the sheet | seat 29 which has flexibility can be obtained by drying only the solvent of the film-formed slurry.
[0066]
Similarly, at least an inorganic filler, a thermosetting resin that is solid at room temperature, and a thermosetting resin composition that is liquid at room temperature and a solvent mixture slurry are prepared, and formed on the releasable film 32 in the same manner as described above, The flexible sheet 29 can also be obtained by drying the solvent.
[0067]
As said thermosetting resin, an epoxy resin, a phenol resin, and cyanate resin can be mentioned, for example. As the inorganic filler, Al₂O_Three, MgO, BN, AlN. Examples of the solvent include ethyl carbitol, butyl carbitol, and butyl carbitol acetate.
[0068]
Examples of the thermosetting resin that is liquid at room temperature include epoxy resins such as bisphenol A type epoxy resins and bisphenol F type epoxy resins, and liquid phenol resins.
[0069]
Furthermore, examples of the solvent include methyl ethyl ketone, isopropanol, and toluene. If necessary, a coupling agent, a dispersant, a colorant, and a release agent can be further added to the composition of the sheet 29.
[0070]
Further, by adding a solvent as described above, adding a liquid thermosetting resin at room temperature, and drying the solvent, the sheet 29 in a semi-cured or partially cured state with an appropriate viscosity (102 to 105 Pa · s) is obtained. Is obtained. If the viscosity is lower than 102 Pa · s, not only the sheet-like material is too sticky to be peeled off from the releasable film 32, but also the workability is poor because the amount of deformation after processing is large. Further, when the viscosity is higher than 105 Pa · s, there is no flexibility and processing at room temperature becomes difficult. Desirably, it is optimal in terms of workability and workability with a viscosity in the range of 103 to 104 Pa · s.
[0071]
When this sheet 29 is cured, a large amount of inorganic filler is filled, so that the thermal expansion coefficient can be made substantially the same as that of the lead frame 30 made of copper plate, and heat dissipation is excellent.
[0072]
8 to 10 are views showing a manufacturing process of the circuit board 28 manufactured using the sheet 29. FIG. As shown in FIG. 8, the lead frame 30 and the sheet 29 are polymerized and integrated by primary molding at 50 to 120 ° C. lower than the thermosetting temperature of the sheet 29.
[0073]
The lead frame 30 can be obtained by punching a copper plate into a desired shape with a die, or can be formed by an etching method.
[0074]
As described above, the lead frame 30 has the conductive pattern 28a on the high-voltage side 28A, the conductive pattern 28b on the low-voltage side 28B, and the dummy pattern 30b therebetween, and the peripheral portions of these patterns 28a, 28b, and 30b are the outer peripheral portions. 30a. The surface of the processed lead frame 30 is treated by nickel plating or solder plating to prevent copper oxidation.
[0075]
Further, the back surface of the lead frame 30 on which the conductive patterns 28a and 28b of the sheet 29 are integrated is increased in surface roughness by sandblasting or the like in order to increase the adhesive strength, and the sheet 29 is likely to be physically adsorbed when heated and melted. However, the rear surface side of the dummy pattern 30b which is finally unnecessary is fixed with a heat-resistant tape or is not roughened so that it can be easily peeled later.
[0076]
FIG. 10 shows that the sheet 33 is superimposed on the surface of the sheet 29 on the back side of the lead frame 30 in the range of 50 to 120 ° C. and press-molded and further heated at a temperature of 120 to 200 ° C. The sheet 29 is fluidized and the thermosetting resin is cured after the conductive patterns 28a, 28b, the conductive patterns 28a and the dummy patterns 30b, and the conductive patterns 28b and the dummy patterns 30b are raised. Indicates. The lead frame 30 has a structure in which the high pressure side 28A and the low pressure side 28B are separated by a dummy pattern 30b as shown in FIG. 8, and after the lead frame 30 is integrated on the sheet 29, a plate body 33 as shown in FIG. Then, the dummy pattern 30 b is separated from the outer peripheral frame 30 a, and then the dummy pattern 30 b is removed from the sheet 29.
[0077]
In this way, if the dummy pattern 30b is removed after the sheet 29 and the lead frame 30 are integrated, the high-pressure side 28A and the low-pressure side 28B of the lead frame 30 are formed on the sheet 29 by the recess 31 as shown in FIGS. Since they are separated, sufficient insulation measures can be taken during this period.
[0078]
When the lead frame 30 and the sheet 29 are integrated, a part of the sheet 29 flows and rises upward between the adjacent patterns. At this time, the dummy pattern 30b exists, and therefore, from FIG. As can be seen, the distance between the patterns is substantially the same as the first distance Ta.
[0079]
For this reason, when the polymer of the sheet 29 and the lead frame 30 is heated and pressed, the amount of the sheet 29 that softens and fluidizes and rises between the patterns is substantially the same between the patterns.
[0080]
As a result, variations in the insulation distance between adjacent patterns due to the pressing of the patterns in the horizontal direction due to the difference in the amount of a part of the sheet 29 protruding between the patterns are eliminated.
[0081]
The conductive patterns 28a and 28b were completed before being integrated with the sheet 29 by providing a resist film on the upper surface with a mask to form the mounting positions and the electrical connection positions of the various electronic components. Various electronic components are mounted in the state of FIG.
[0082]
Furthermore, after the outer peripheral portion 30a of the lead frame 30 is cut off, a portion protruding outward from the circuit board 28 is bent upward, for example, and used as a connection terminal to another circuit board.
[0083]
Further, a heat radiating plate can be provided on the lower surface of the sheet 29 to further enhance the heat dissipation.
[0084]
Next, other characteristic points of the present embodiment will be described.
[0085]
In this embodiment, as shown in FIGS. 6 and 9, between the conductive patterns 28a and 28b, and between them and the dummy pattern 30b, the lower sheet 29 is above the upper surfaces of the conductive patterns 28a, 28b and the dummy pattern 30b. Protrusively up to. And only the both sides on the upper surface of the conductive patterns 28a, 28b located on both sides thereof are covered.
[0086]
For this reason, between the adjacent conductive patterns 28a and 28b, the conductive patterns 28a and 28b protrude above the upper surfaces of the conductive patterns 28a and 28b and cover both sides of the upper surfaces of the conductive patterns 28a and 28b. As a result, the effective insulation distance between the adjacent conductive patterns 28a and 28b can be prevented from being short-circuited.
[0087]
In order to achieve the above, the plate 33 has a lower surface on the side of the lead frame 30 as shown in FIG. 10 and is opposed to between the conductive patterns 28a and 28b constituting the lead frame 30 and between the dummy pattern 30b. A concave portion 33a is formed in the portion to be directed upward from the lead frame 30 toward the plate body 33 side. The recess 33a extends to both sides of the conductive patterns 28a and 28b located on both sides thereof.
[0088]
For this reason, by applying pressure while heating the polymer of the sheet 29, the lead frame 30, and the plate body 33 as described above, a part of the sheet 29 is fluidized between the conductive patterns 28a, 28b, and the dummy pattern 30b. As shown in FIG. 10, the gap rises and enters the recess 33 a of the plate 33.
[0089]
In this case, since the concave portion 33a of the plate 33 extends to both sides of the conductive patterns 28a and 28b located on both sides of the concave portion 33a as described above, the melt of the sheet 29 penetrates into the concave portion 33a and becomes conductive. Both sides of the patterns 28a and 28b are covered.
[0090]
As a result, the effective insulation distance between adjacent conductive patterns 28a and 28b is increased.
[0091]
Further, only by forming the recess 33a in the plate 33, a part of the sheet 29 can be protruded toward the plate 33 between the conductive patterns 28a and 28b, and both sides of the conductive patterns 28a and 28b can be covered. It can also increase productivity.
[0092]
The plate 33 has flexibility and heat resistance. When the plate 33 has flexibility as described above, the plate 33 comes into close contact with the upper surface of the lead frame 30, so that the conductive pattern 28a outside the recess 33a, A part of the sheet 29 does not flow out to the upper surface of 28b.
[0093]
That is, as described above, an electronic component or the like is mounted on the conductive patterns 28a and 28b. If the portion is covered with the outflow portion of the sheet 29, the electronic component cannot be mounted or the sheet 29 is not mounted. Since extra work such as a removal step of the outflow portion of the water is necessary, these are prevented.
[0094]
Further, when the plate 33 is formed of resin and a heat transfer member is mixed in the resin, heat can be easily transferred from the plate 33 side to the lead frame 30 and the sheet 29. As a result, the sheet 29 Can be fluidized smoothly.
[0095]
Further, from the viewpoint of heat conduction, the plate body 33 may be formed of a metal plate, which makes it easy to transfer heat from the plate body 33 side to the lead frame 30 and the sheet 29, and as a result, the sheet 29 is smoothly smoothed. To be fluidized.
[0096]
Since the dummy pattern 30b is an uncovered portion of the protruding portion of the sheet 29 as shown in FIG. 10, the dummy pattern 30b can be easily peeled off from the sheet 29.
[0097]
Further, since the inner surface of the concave portion 33a of the plate 33 is a mirror surface, a part of the sheet 29 flowing out between the conductive patterns 28a and 28b is not firmly adhered to the inner surface of the concave portion 33a. Can be smoothly removed.
[0098]
Of course, a release agent may be applied to the inner surface of the concave portion 33a of the plate 33 so that a part of the sheet 29 does not adhere firmly to the inner surface of the concave portion 33a.
[0099]
Further, if a concave hole 33a is formed in the concave portion 33a of the plate body 33, a part of the sheet 29 is present in that portion when flowing between the conductive patterns 28a, 28b and the like toward the concave portion 33a. As a result, a part of the sheet 29 can flow smoothly.
[0100]
Further, if the bottom surface of the concave portion 33a of the plate body 33 is formed in a dome shape protruding upward on the opposite side of the lead frame 30, and a vent hole is formed in the center portion of the dome, the air can be more easily removed. A part of the plate 33 smoothly enters the recess 33a of the plate 33.
[0101]
【The invention's effect】
As described above, the present invention includes an insulating sheet and a lead frame superposed on the sheet, and the lead frame has a plurality of conductive patterns. The sheet protrudes to the upper side of the upper surface of the conductive pattern, and covers the side facing the other conductive pattern on the upper surface of at least one of the conductive patterns located on both sides thereof.
[0102]
With such a configuration, the lower insulating sheet protrudes between the adjacent conductive patterns up to the upper surface, and on the upper surface of at least one of the conductive patterns located on both sides, the other Since the side facing the conductive pattern is covered, the effective insulation distance between the adjacent conductive patterns is increased. As a result, not only can the short-circuit between these adjacent conductive patterns be prevented, but the adjacent portions are also adjacent. It is also possible to reduce the size by shortening the distance between the conductive patterns.
[Brief description of the drawings]
FIG. 1 is a configuration diagram of an automobile adopting an embodiment of the present invention.
FIG. 2 is a configuration diagram of an electric circuit according to the embodiment.
FIG. 3 is a circuit diagram showing a DC / DC converter and a write connection in the embodiment;
FIG. 4 is a circuit diagram of a DC / DC converter according to the embodiment.
FIG. 5 is a plan view of the circuit board according to the embodiment;
6 is a cross-sectional view of main parts taken along line AB in FIG. 5;
FIG. 7 is a sectional view showing a manufacturing process of the circuit board.
FIG. 8 is a plan view of the same.
FIG. 9 is a sectional view of the same.
FIG. 10 is a sectional view of the same.
[Explanation of symbols]
28A High pressure side
28B Low pressure side
28a Conductive pattern
28b Conductive pattern
29 seats
30 Lead frame
30b Dummy pattern
33 Plate
33a recess
Ta first distance
Tb second distance

Claims (10)

An insulating sheet, and a high-voltage side lead frame and a low-voltage side lead frame that are superposed on the sheet and are adjacent to each other with a separation portion interposed therebetween, and each of the high-voltage side lead frame and the low-voltage side lead frame includes a plurality of conductive patterns Between the conductive patterns, the lower sheet protrudes up to the upper surface of the conductive pattern, and opposes the other conductive pattern on the upper surface of at least one of the conductive patterns located on both sides thereof. The distance between the conductive pattern on the high voltage side and the conductive pattern on the low voltage side where the high voltage side lead frame and the low voltage side lead frame are adjacent to each other is between the adjacent conductive patterns on the high voltage side and the low voltage side. A circuit board that is longer than between adjacent conductive patterns. The circuit board according to claim 1, wherein a recess is formed in a sheet in a separation portion between the high-voltage side lead frame and the low-voltage side lead frame. An insulating sheet is polymerized on one of the front and back surfaces of the lead frame, and a flexible plate is polymerized on the other, then the three polymers are heated and pressurized, and then the plate is removed from the lead frame. In the method of manufacturing a circuit board to be peeled off, a recess facing from the lead frame to the plate body side is formed on the surface of the plate body on the lead frame side facing the conductive pattern constituting the lead frame. The method of manufacturing a circuit board in which the recess is extended to the side surface of at least one plate of the conductive pattern located on both sides of the recess. The method for manufacturing a circuit board according to claim 3, wherein the plate body is formed of a resin, and a heat transfer body is mixed in the resin. An insulating sheet is polymerized on one of the front and back surfaces of a lead frame composed of a high-voltage-side lead frame and a low-voltage-side lead frame arranged with a dummy pattern in between, and a plate is polymerized on the other, and then these three polymers are heated. In the method of manufacturing a circuit board, the plate body is peeled from the lead frame, and then the dummy pattern is removed from the sheet after the lead frame is integrated on the sheet. On the surface facing the lead frame, a portion facing the conductive pattern constituting the lead frame is formed with a concave portion from the lead frame toward the plate body, and the concave portion is electrically conductive located on both sides of the concave portion. A method of manufacturing a circuit board that extends to at least one plate side surface of a pattern. 6. The method of manufacturing a circuit board according to claim 5, wherein the dummy pattern is an uncovered portion of the protruding portion of the sheet. A plurality of conductive patterns are provided on each of the high-voltage side lead frame and the low-voltage side lead frame, and a lead frame in which substantially the same first distance is formed between adjacent patterns among these conductive patterns and dummy patterns is used. 6. The method for manufacturing a circuit board according to claim 5, wherein the sheet is integrated on the sheet, the sheet between the adjacent first distance patterns is raised to the upper surface of the conductive pattern, and then the dummy pattern is removed. 8. The method for manufacturing a circuit board according to claim 6, wherein the lower surface side of the conductive pattern of the low voltage side lead frame and the high voltage side lead frame is a rough surface, and the lower surface side of the dummy pattern is a non-rough surface. The method for manufacturing a circuit board according to claim 3, wherein a vent is formed in the concave portion of the plate body. 10. The method for manufacturing a circuit board according to claim 9, wherein the bottom surface of the concave portion of the plate body is formed in a dome shape protruding to the opposite side of the lead frame, and a vent hole is formed in the center portion of the dome.

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