Wiring board and wiring board connecting apparatus

The present invention provides a wiring board including a first board provided with a first wiring pattern and a second board provided with a second wiring pattern while the first wiring pattern and the second wiring pattern are electrically connected, wherein the first board includes: a board insertion opening in which the second board is inserted; and a first connection pattern provided inside the board insertion opening and electrically connected to the first wiring pattern, and the second board includes: an inserting portion to be inserted into the board insertion opening of the first board; and a second connection pattern provided at a position opposed to the first connection pattern and electrically connected to the second wiring pattern in the case where the inserting portion of the second board is inserted into the board insertion opening of the first board, and further comprising: solder or brazing filler metal applied at least to a surface of one of the first connection pattern and second connection pattern; and a heat generating device which generates heat by energization and melts the solder or the brazing filler metal to connect the first connection pattern with the second connection pattern.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a wiring board and a wiring board connecting apparatus, and in particular, to the wiring board configured by connecting multiple boards, and the like.

2. Description of the Related Art

Conventionally, there is a disclosure (Japanese Patent Application Laid-Open No. 2002-280690) of a coupling structure of a printed wiring board in which a notched portion is formed on the printed wiring board and a flexible printed wiring board is inserted into the notched portion so as to implement electrical continuity between a pattern on the printed wiring board and a pattern on the flexible printed wiring board. According to Japanese Patent Application Laid-Open No. 2002-280690, there is no need to provide a connector for connecting the hard printed wiring board with the flexible printed wiring board, a land for connection and the like, and so space on the printed wiring board can be effectively exploited.

According to Japanese Patent Application Laid-Open No. 2002-280690, the pattern on the printed wiring board and the pattern on the flexible printed wiring board are merely in contact, or are only in conduction because of a contact pin biased by a spring. Therefore, there was a problem as to connection strength between the printed wiring boards.

The present invention has been made in view of such circumstances, and an object thereof is to provide a wiring board and a wiring board connecting apparatus capable of mutually attaching and removing the boards with ease and connecting wiring patterns on the boards with certainty.

SUMMARY OF THE INVENTION

To attain the object, a wiring board according to a first aspect is the one including a first board provided with a first wiring pattern and a second board provided with a second wiring pattern while the first wiring pattern and the second wiring pattern are electrically connected, wherein the first board includes: a board insertion opening in which the second board is inserted; and a first connection pattern provided inside the board insertion opening and electrically connected to the first wiring pattern, and the second board includes: an inserting portion to be inserted into the board insertion opening of the first board; and a second connection pattern provided at a position opposed to the first connection pattern and electrically connected to the second wiring pattern in the case where the inserting portion of the second board is inserted into the board insertion opening of the first board, and further comprising: solder or brazing filler metal applied at least to a surface of one of the first connection pattern and second connection pattern; and a heat generating device which generates heat by energization and melts the solder or the brazing filler metal to connect the first connection pattern with the second connection pattern.

According to the first aspect, it is possible to attach and remove the first and second boards with ease and connect the first and second wiring patterns with certainty by using solder or brazing filler metal.

The wiring board according to a second aspect is the one according to the first aspect, wherein the heat generating device is provided on a backside surface of the surface provided with the second connection pattern in the inserting portion. The second aspect limits a position at which the heat generating device is provided.

The wiring board according to a third aspect is the one according to the first aspect, wherein the second board is a multilayer board having multiple layers laminated therein, and the heat generating device is provided between the multiple layers. The third aspect limits the position at which the heat generating device is provided by rendering the second board as the multilayer board.

The wiring board according to a fourth aspect is the one according to the second or third aspect, wherein the heat generating device is provided at a position overlapping the second connection pattern.

According to the fourth aspect, the heat generating device is formed to overlap the second connection pattern formed on another surface or layer so as to effectively heat the solder or the brazing filler metal for connecting the first connection pattern with the second connection pattern.

The wiring board according to a fifth aspect is the one according to the fourth aspect, wherein the heat generating device is an electrothermal pattern or a filiform heating element for generating heat by energization and is provided according to a form of the second connection pattern. The fifth aspect limits the kind of the heat generating device.

The wiring board according to a sixth aspect is the one according to the fifth aspect, wherein the electrothermal pattern or the filiform heating element is provided on the backside of the second connection pattern or in proximity thereto, and the second board is provided with a wiring of low electrical resistance for supplying electric power to the electrothermal pattern or the filiform heating element.

According to the sixth aspect, it is possible to effectively heat only the second connection pattern.

The wiring board according to a seventh aspect is the one according to the first to sixth aspects, wherein the heat generating device is grounded on operation of a circuit configured by connecting the first wiring pattern with the second wiring pattern. The wiring board according to an eighth aspect is the one according to the first to sixth aspects, wherein the heat generating device is grounded via a capacitor.

According to the seventh and eighth aspects, it is possible to avoid trouble to the operation of the circuit caused by an induced current or an induced voltage to the connection pattern due to a guide signal generated by the heat generating device induced by a signal current, a signal voltage, disturbance noise or the like passing the first and second wiring patterns on the operation of the circuit configured by connecting the first and second wiring patterns.

The wiring board according to a ninth aspect is the one according to the first to eighth aspects, further comprising a smoothing device which is formed further on an insertion end side than the second connection pattern on the surface of the second board having the second connection pattern formed thereon and heated by energization on insertion or separation to smooth the surface of the solder or the brazing filler metal attached to the first connection pattern.

According to a ninth aspect, it is possible to perform secure soldering or brazing by smoothing the solder or the brazing filler metal attached to the first connection pattern on inserting the second board.

A wiring board according to a tenth aspect is the one including a first board provided with a first wiring pattern and a second board provided with a second wiring pattern while the first wiring pattern and the second wiring pattern are electrically connected, wherein the first board includes: a board insertion opening in which the second board is inserted; a first connection pattern provided inside the board insertion opening and electrically connected to the first wiring pattern; and a beam introduction opening for introducing a heating beam for heating the first connection pattern, and the second board includes: an inserting portion to be inserted into the board insertion opening of the first board; and a second connection pattern provided at a position opposed to the first connection pattern on the inserting portion and electrically connected to the second wiring pattern in the case where the inserting portion of the second board is inserted into the board insertion opening of the first board, and further comprising: a solder or a brazing filler metal applied at least to a surface of one of the first connection pattern and second connection pattern and heated and melted by the heating beam introduced from the beam introduction opening to connect the first connection pattern with the second connection pattern.

According to the tenth aspect, it is possible to easily attach and remove the first and second boards and securely connect the first and second wiring patterns by using the solder or the brazing filler metal.

The wiring board according to an eleventh aspect is the one according to the tenth aspect, wherein the beam introduction opening is formed on the backside of the first connection pattern on the first board. The eleventh aspect limits the position at which the beam introduction opening is formed.

The wiring board according to a twelfth aspect is the one according to the tenth aspect, wherein the beam introduction opening is formed by at least one to penetrate a wall surface of the board insertion opening of the first board, and the second board further includes a heat conduction member consisting of a highly heat-conductive material and provided on a surface facing the beam introduction opening in the case where the inserting portion of the second board is inserted into the board insertion opening of the first board. The wiring board according to the thirteenth aspect is the one according to the tenth aspect, wherein the beam introduction opening is formed by at least one to penetrate a wall surface of the board insertion opening of the first board, and the second board is a multilayer board having multiple layers laminated therein and further includes a heat conduction member consisting of a highly heat-conductive material provided to a layer inside the inserting portion.

According to the twelfth and thirteenth aspects, it is possible to heat the solder or the brazing filler metal by heating the heat conduction member with the heating beam.

The wiring board according to the fourteenth aspect is the one according to the twelfth and thirteenth aspect, wherein the heat conduction member includes at least one substance out of copper, aluminum and iron. A fourteenth aspect limits the material configuring the heat conduction member.

The wiring board according to a fifteenth aspect is the one according to the first to fourteenth aspects, further comprising a high-heat expanding member to be expanded by heating which is provided on a surface different from the surface of the second board having the second connection pattern formed thereon.

According to the fifteenth aspect, the high-heat expanding member is expanded on heating the first and second connection patterns so that the second connection pattern is pressed against or approaches the first connection pattern to allow secure soldering.

The wiring board according to a sixteenth aspect is the one according to the fifteenth aspect, wherein the high-heat expanding member includes at least one substance out of copper, aluminum, iron and ceramics. The sixteenth aspect limits the material configuring the high-heat expanding member.

The wiring board according to a seventeenth aspect is the one according to the fifteenth and sixteenth aspect, wherein the high-heat expanding member is grounded.

According to the seventeenth aspect, it is possible to avoid trouble to the operation of the circuit caused by an induced current or an induced voltage to the connection pattern due to a guide signal generated by the high-heat expanding member induced by a signal current, a signal voltage, disturbance noise or the like passing the first and second wiring patterns on the operation of the circuit configured by connecting the first and second wiring patterns.

The wiring board according to an eighteenth aspect is the one according to the first to seventeenth aspects, wherein the second board is formed by a material including the substance to be expanded by heating.

According to the eighteenth aspect, the second board is expanded on heating the first and second connection patterns so that the second connection pattern is pressed against or approaches the first connection pattern to allow secure soldering.

The wiring board according to a nineteenth aspect is the one according to the eighteenth aspect, wherein the second board contains ceramics of a high heat expansion coefficient. The nineteenth aspect limits the material configuring the second board.

The wiring board according to a twentieth aspect is the one according to the first to nineteenth aspects, wherein the first board further includes a first reinforcing pad provided inside the board insertion opening and electrically unconnected to the first wiring pattern, the second board further includes a second reinforcing pad provided at the position opposed to the first reinforcing pad and electrically unconnected to the second wiring pattern in the case where the inserting portion of the second board is inserted into the board insertion opening of the first board; and the solder or the brazing filler metal is applied to the surface of at least one of the first reinforcing pad and second reinforcing pad.

According to the twentieth aspect, it is possible to provide the reinforcing pads in addition to the connection patterns and solder or braze them so as to improve connection strength between the first and second boards.

The wiring board according to a twenty-first aspect is the one according to the first to twentieth aspects, wherein the second board further includes a heating profile transmitting device which records a heating profile on heating the solder or the brazing filler metal and transmits the heating profile to a wiring board connecting apparatus.

According to the twenty-first aspect, it is possible to automate setting of the heating profile.

The wiring board according to a twenty-second aspect is the one according to the twenty-first aspect, wherein the heating profile transmitting device is an IC tag. An twenty-second aspect limits the heating profile transmitting device to the IC tag (RFID tag).

A wiring board connecting apparatus according to a twenty-third aspect is the one comprising: a heating device which heats a connection pattern provided on a board and melts solder or brazing filler metal applied to the connection pattern; a heating profile recording device which records a heating profile on heating the solder or the brazing filler metal; and a control device which controls heat applied to the connection pattern based on the heating profile. A wiring board connecting apparatus according to a twenty-fourth aspect is the one comprising: a heating device which heats a connection pattern provided on a board and melts solder or brazing filler metal applied to the connection pattern; a heating profile receiving device which receives the heating profile from a heating profile transmitting device provided on the board; and a control device which controls heat applied to the connection pattern based on the received heating profile.

According to the twenty-third and twenty-fourth aspects, it is possible to heat the solder or the brazing filler metal according to the heating profile which is set up by considering characteristics of the first and second boards.

The wiring board connecting apparatus according to a twenty-fifth aspect is the one according to the twenty-third and twenty-fourth aspects, wherein the heating device is a power supply provided on the board for energizing the heat generating device which generates heat by energization and heats the connection pattern. The wiring board connecting apparatus according to a twenty-sixth aspect is the one according to the twenty-fourth aspect, wherein the heating device is a power supply provided on the board for energizing the heating device which generates heat by energization and heats the wiring pattern, and the heating profile receiving device is provided to a power supply probe connected to a power generation device of the board or in proximity to the power supply probe. The twenty-fifth and twenty-sixth aspects limit the heating device to the power supply which is provided on the board and energizes the heating device.

The wiring board connecting apparatus according to a twenty-seventh aspect is the one according to the twenty-fifth or twenty-sixth aspect, further comprising: a voltage measuring device which measures a voltage applied to the power generation device, and wherein the control device stops the energization to the power generation device in the case where the measured voltage is out of a predetermined range of values.

According to the twenty-seventh aspect, it is possible to stop the energization in the case where the power generation device has a fault, such as a bad connection or a short for instance.

The wiring board connecting apparatus according to a twenty-eighth aspect is the one according to the twenty-seventh aspect, further comprising a warning output device which outputs a warning when the energization stops.

According to the twenty-eighth aspect, it is possible to output warning display or warning voice on stopping the energization.

The wiring board connecting apparatus according to a twenty-ninth aspect is the one according to the twenty-third or twenty-fourth aspect, wherein the heating device is a heating beam source for introducing a heating beam to the connection pattern of the board. The wiring board connecting apparatus according to a thirtieth aspect is the one according to the twenty-ninth aspect, wherein the heating beam source includes: a laser source for generating a laser beam; and an optical fiber for radiating the laser beam via a beam introduction opening formed on the board. The twenty-ninth and thirtieth aspects limit the heating device to the heating beam source.

The wiring board connecting apparatus according to a thirty-first aspect is the one according to the thirtieth aspect, wherein an end of the optical fiber is concave.

According to the thirty-first aspect, it is possible to radiate the laser beam in a wide range by forming the end of the optical fiber to be concave.

The wiring board connecting apparatus according to a thirty-second aspect is the one according to the twenty-ninth to thirty-first aspects, wherein the optical fiber guides an infrared ray generated in a region radiated by the laser beam, and further comprising a temperature calculating device which calculates a temperature of the region radiated by the laser beam based on the infrared ray guided by the optical fiber.

According to the thirty-second aspect, it is possible to acquire the temperature of the region radiated by the laser beam.

The wiring board connecting apparatus according to a thirty-third aspect is the one according to the thirty-second aspect, wherein the temperature calculating device calculates the temperature of the region radiated by the laser beam by predetermined time, and stops radiation of the laser beam in the case where the measured temperature is out of a predetermined range of values.

According to the thirty-third aspect, it is possible to stops the radiation of the laser beam in the case of abnormal heating or in the case where the laser beam is radiated at a point other than the point to be heated.

The wiring board connecting apparatus according to a thirty-fourth aspect is the one according to the thirty-third aspect, further comprising a warning output device which outputs a warning when the radiation of the laser beam stops.

According to the thirty-fourth aspect, it is possible to output warning display or warning voice on stopping the radiation of the laser beam.

According to the present invention, it is possible to attach and remove the first and second boards with ease and connect the first and second wiring patterns with certainty by using the solder or the brazing filler metal.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Hereunder, preferred embodiments of a wiring board and a wiring board connecting apparatus according to the present invention will be described with reference to the attached drawings.

[Overall Configuration of the Wiring Board]

FIG. 1is a perspective view showing the wiring board according to an embodiment of the present invention. As shown inFIG. 1, the wiring board of this embodiment is a flexible rigid board in which a multilayer board10is combined with a flexible board20which is detachable from the multilayer board10. The multilayer board10is configured by sticking three boards10-1,10-2and10-3together in order. The second layer10-2is a little thicker than the flexible board20, and a part thereof is notched and has a board insertion opening10A for inserting the flexible board20formed thereon. To facilitate insertion of the flexible board20, an insertion end (the end to be inserted into the board insertion opening10A) of the flexible board20may be a little thinner or the board insertion opening10A may be wider toward outside.

The multilayer board10and flexible board20are given unique identification signs (such as ID numbers), one-dimensional codes, two-dimensional codes and the like so that a combination of the multilayer board10and flexible board20is identifiable.

The number of layers configuring the multilayer board10is not limited to three layers. Multiple board insertion openings10A may be formed on one multilayer board10to allow multiple flexible boards20to be connected.

FIGS. 2A and 2Bare 2 to 2 sectional views ofFIG. 1. As shown inFIGS. 2A and 2B, wiring patterns12-1and12-3are formed on surfaces of the sides of the first layer10-1and third layer10-3of the multilayer board10stuck together with the second layer10-2. Connection patterns14are formed on the surface inside the board insertion opening10A of the third layer10-3, which is electrically connected to the wiring pattern12-3.

Wiring patterns not shown are formed on the surfaces outside the board insertion opening10A of the first layer10-1and third layer10-3, where electronic components16,16. . . are mounted.

As shown inFIGS. 2A and 2B, a wiring pattern22and a connection pattern24are formed, on an underside of the flexible board20. The connection pattern24is electrically connected to the wiring pattern22, and a solder26is applied to the surface of the connection pattern24. The solder26may be either applied to the surface of the connection patterns14of the multilayer board10or applied to both the connection patterns14and24. A brazing filler metal which is electrically conductive and melts by heating, an electrically conductive adhesive or the like may also be used instead of the solder26.

As shown inFIG. 2B, the connection patterns14of the multilayer board10and the connection patterns24of the flexible board20are formed to be in a mutually opposed (overlapping) positional relation in the case where the flexible board20is inserted into the board insertion opening10A of the multilayer board10.

An electrothermal pattern28is formed on the backside of the connection pattern24of the flexible board20. The electrothermal pattern28is a pattern to be heated by energization, which is formed by attaching a material of a nickel-chromium system or an iron-chromium system to the surface of the flexible board20by coating, printing, etching, vapor deposition or the like. A mechanism for supplying a current to the electrothermal pattern28will be described later. The electrothermal pattern28may also be formed by using a material such as a filiform heating element.

Next, a procedure for connecting the multilayer board10with the flexible board20will be described with reference toFIGS. 2A and 2Band the like. In the case of connecting the multilayer board10with the flexible board20, the flexible board20is inserted into the board insertion opening10A of the multilayer board10first, and positioning is performed so that the connection patterns14and24become opposed (overlapping) as shown inFIGS. 2A and 2B. Next, the electrothermal pattern28is energized and heated. And then, the solder26applied to the surface of the connection pattern24is melted by the heat conducted from the electrothermal pattern28to the connection pattern24via the flexible board20. If the energization to the electrothermal pattern28is stopped, the solder26dissipates heat and coagulates. Thus, the connection patterns14of the multilayer board10are connected with the connection patterns24of the flexible board20via the solder26, and the wiring pattern12-3is electrically connected with the wiring pattern22.

Next, a procedure for separating the multilayer board10from the flexible board20will be described with reference toFIGS. 2A,2B and the like. In the case of separating the multilayer board10from the flexible board20, the electrothermal pattern28is energized in a state where the multilayer board10is connected with the flexible board20(refer toFIG. 2B) first, and the solder26connecting the connection patterns14with the connection patterns24is melted. Next, as shown inFIG. 2A, the flexible board20is pulled out of the board insertion opening10A of the multilayer board10. Thus, the multilayer board10is separated from the flexible board20.

According to this embodiment, it is possible to connect the connection patterns14of the multilayer board10with the connection patterns24of the flexible board20more securely with the solder26and the like and also connect the multilayer board10with the flexible board20or separate the multilayer board10from the flexible board20easily by melting the solder26with the electrothermal pattern28. Furthermore, it is no longer necessary to have space for placing connectors and the like for connection of the flexible board20on the surface of the multilayer board10for mounting the electronic components16. Therefore, it is possible to effectively exploit the space on the multilayer board10and flexible board20.

As for the flexible board20, there are various forms such as the flexible board20having the electronic components mounted thereon, a form having the flexible board sandwiched between hard boards and a wire harness used for connection between the flexible boards20. However, the connection method of the wiring board of this embodiment is applicable to all the forms of the flexible board20.

First Embodiment of the Flexible Board

Next, a description will be given with reference toFIG. 3onward as to placement of the electrothermal pattern28formed on the flexible boards20of this embodiment.FIG. 3is a plan view showing the electrothermal pattern28on the flexible boards20according to a first embodiment of the present invention. As shown inFIG. 3, the electrothermal pattern28is provided according to the position of the connection pattern24provided on the backside of the flexible board20. It is thereby possible to conduct heat securely to the connection pattern24so as to melt the solder26by brief energization. As the solder26can be melted by a minimum amount of heat, it is possible to thin the electrothermal pattern28and suppress a current value for energization. It is also possible to prevent the flexible board20and multilayer board10from being damaged by excessive heating.

InFIG. 3, reference numerals18and30denote reinforcing pads for reinforcing the connection between a multilayer board30and the flexible boards20. The reinforcing pads18and30are the patterns formed as with the wiring patterns12,22and connection patterns14,24for instance, which are formed by attaching a material such as copper foil to the surface by coating, printing, etching, vapor deposition or the like, for instance. The reinforcing pads18are formed on the same surface on which the connection patterns14of the multilayer board10are formed. The reinforcing pads30are formed on the same surface on which the connection pattern24of the flexible board20is formed. The reinforcing pads18and30are formed to be in a mutually opposed positional relation in the case where the flexible board20is inserted into the board insertion opening10A of the multilayer board10.

Unlike the connection patterns14and24, the reinforcing pads18and30are isolated from the wiring patterns12-3and22respectively. Solder or brazing filler metal is applied to at least one of the surfaces of the reinforcing pads18and30as with the connection patterns14and24. As for the flexible board20, the electrothermal pattern28is formed on the backsides of the reinforcing pads30, and is connected by the solder or brazing filler metal melted by the electrothermal pattern28as with the connection patterns14and24. Thus, connection strength between the multilayer board10and the flexible board20is improved.

The numbers and positions of the reinforcing pads18and30are not limited to those inFIG. 3. It is not necessary to provide the reinforcing pads18and30in the case where the connection strength between the multilayer board10and the flexible board20can be sufficiently secured by the connection of the connection patterns14and24.

As shown inFIG. 4, it is desirable to have the electrothermal pattern28evenly at the position corresponding to the connection patterns24and render length of the electrothermal pattern28against unit area of the connection patterns24or the reinforcing pads30equal as to each of the connection patterns24and the reinforcing pads30. In the case where thickness of the flexible board20is not even, that is, in the case where the insertion end side of the flexible board20is thinner to be easily inserted into the board insertion opening10A for instance, the length of the electrothermal pattern28against the unit area of the connection pattern24should be changed according to the thickness of the flexible board20(for instance, the length of the electrothermal pattern28overlapping the connection pattern24should be rendered shorter on the side where the flexible board20is thinner). Thus, the amount of heat conducted to each of the connection patterns24becomes even so that soldering reliability is improved. It is also possible to even out the amount of heat conducted to each of the connection patterns24by changing the thickness (pattern width and thickness) of the electrothermal pattern28according to the form of the connection pattern24, thickness of the flexible board20and the like (by thinning the pattern width of the electrothermal pattern28overlapping the connection patterns24on the side where the flexible board20is thinner for instance).

In the case where a sufficient amount of heat is generable (in the case where tolerance against the heat of the flexible board20and multilayer board10is high) or in the case where a sufficiently large current can be passed through the electrothermal pattern28, it is sufficient to have the electrothermal pattern28partially overlap the connection patterns24on the backside of the flexible board20as shown inFIG. 5.

Next, a description will be given with reference toFIG. 3as to a route for supplying the current to the electrothermal pattern28. As shown inFIG. 3, the electrothermal pattern28is connected to energization pads34via wiring patterns32. The energization pads34are connected with power supply probes52of a wiring board connecting apparatus (power supply unit)50to have the current supplied thereto. A description will be given later as to control over the current value and voltage value supplied from the power supply unit50and energization time.

The wiring patterns32are patterns of which amount of heat by energization is small (such as a pattern consisting of a material of low electrical resistance or a copper foil pattern). To be more specific, the electrothermal pattern28is only formed at a position which is the backside of the connection pattern24. It is thereby possible to prevent a loss of the applied voltage and also prevent the flexible board20and the multilayer board10from being damaged due to excessive heating because no region other than the connection pattern24is heated.

A connection point36between the electrothermal pattern28and the wiring patterns32has lower mechanical strength compared to other patterns because their materials are different. For this reason, the connection point36between the electrothermal pattern28and the wiring patterns32is placed inside the board insertion opening10A in the case where the flexible board20is inserted into the board insertion opening10A of the multilayer board10(the position of the multilayer board10in this case is corresponding to reference numeral10′ ofFIG. 3). Thus, it is possible to prevent a crack from being generated in the electrothermal pattern28, wiring patterns32, connection point36or in proximity thereto due to a bending stress applied to the flexible board20and resulting in a break.

As for the example shown inFIG. 3, the flexible board20is a straight type of a constant width. As shown inFIG. 6, however, it is possible to narrow the width of the portion of the flexible board20not inserted into the multilayer board10by placing the energization pads34closer to the wiring pattern22side. It is also possible to expand the width of the portion of the flexible board20not inserted into the multilayer board10.

As shown inFIG. 3and the like, the electrothermal pattern28is a pattern traversing the connection pattern24. For this reason, on operation of a circuit configured by connecting the multilayer board10with the flexible board20, the electrothermal pattern28is apt to be induced by electrical signals of the wiring patterns12,22and the like. There is a possibility that the signal generated by this induction in the electrothermal pattern28may have adverse effects as noise on other electrical signals. Thus, the electrothermal pattern28is grounded (connected to a ground or an earth) on operation of the circuit so as to reduce the effects of the noise on operation of the circuit.

FIG. 7is a diagram schematically showing a state of grounding the electrothermal pattern28. As shown inFIG. 7, the electrothermal pattern28is grounded via a jumper component38(such as a 0 Ω resistance) on operation of the circuit after connecting the multilayer board10with the flexible board20. On grounding the electrothermal pattern28, the wiring patterns32and energization pads34conducting with the electrothermal pattern28are simultaneously grounded. It is also possible, however, to ground the wiring patterns32and energization pad34individually by considering spacing of grounding points for instance. In the case of separating the multilayer board10from the flexible board20, the jumper component38is removed before starting the energization to the electrothermal pattern28so as to release the grounding.

As for the example shown inFIG. 7, the electrothermal pattern28is grounded at three points (grounded via the energization pad34at two points and directly connected to the jumper component38at one point). However, the number and placement of the points to be grounded are not limited thereto. When releasing the grounding, one of the jumper components38connected to the energization pad34does not have to be removed considering positive and negative of the voltage applied from the power supply unit50. It is also possible to provide a switch between the electrothermal pattern28and the ground so as to release the grounding without removing the jumper component38.

When grounding the electrothermal pattern28, it can be grounded via a capacitor instead of the jumper component38shown inFIG. 7. In the case where the electrothermal pattern28is grounded via the capacitor, it is possible to apply the voltage to the energization pad34in the state of connecting the capacitor to the electrothermal pattern,28as-is.

According to the embodiment, the electrothermal pattern28was formed on the flexible board20side. However, the electrothermal pattern28may also be formed on the surface side of the multilayer board10. In the case where the multilayer board10consists of four or more layers, the electrothermal pattern28may be provided to the layer close to the connection patterns14.

EXAMPLE IN WHICH THE FLEXIBLE BOARD IS A MULTILAYER BOARD

The flexible board may also be a multilayer board.FIG. 8is a sectional view showing an example in which the flexible board20is a multilayer board. In the example shown inFIG. 8, the flexible board20is configured by sticking two boards20-1and20-2together. A wiring pattern22-1and a connection pattern24-1electrically connected to the wiring pattern22-1are formed on an outer surface (the backside of the surface stuck together) of the first layer20-1. A wiring pattern22-2and a connection pattern24-2electrically connected to the wiring pattern22-2are formed on the outer surface (the backside of the surface stuck together) of the second layer20-2. The multilayer board10has connection patterns14-1and14-2formed at the positions opposed to the connection patterns24-1and24-2respectively in the case where the flexible board20is inserted into the board insertion opening10A. And the above-mentioned electrothermal pattern28is formed between the first layer20-1and the second layer20-2. The electrothermal pattern28may be formed either on the first layer20-1or on the second layer20-2. As for the example shown inFIG. 8, it is possible to evenly heat the connection patterns24-1and24-2on both sides by creating a structure sandwiching the electrothermal pattern28between the layers.

Even in the case where the flexible board20is a multilayer board, it is possible to efficiently heat the connection patterns24-1and24-2on both sides by placing the electrothermal pattern28correspondingly to the positions of the connection patterns24-1and24-2on both sides as inFIGS. 3 and 4.

Embodiment of the Wiring Board Connecting Apparatus (Power Supply Unit)

Next, an embodiment of the power supply unit50will be described.FIG. 9is a block diagram showing a main configuration of the power supply unit50. As shown inFIG. 9, the power supply unit50includes a controlling circuit54, an operating portion56, a display portion58, a storage portion60, an external storage medium62and an external connecting terminal64.

The controlling circuit54is a control portion for integrally controlling the power supply unit50. The controlling circuit54controls the operation of the power supply unit50based on signal inputs from the operating portion56and the like. The operating portion56includes a power switch of the power supply unit50, a heating start switch for starting supply of a current to the power supply probes52and various other operating switches. The display portion58is a monitor for displaying various operation menus and set contents and also displaying a warning. The storage portion60is an apparatus for storing data, programs and the like necessary to control the power supply unit50, which is a memory (a non-volatile memory for instance) built into the power supply unit50for instance. The external storage medium62is a storage medium detachable from the power supply unit50, which is a semiconductor memory such as a memory card, an optical disk such as a CD or a DVD or a magnetic disk such as an HDD for instance. The external connecting terminal64is an interface for communication with an external device66(such as a personal computer), which is a USB for instance.

As shown inFIG. 9, the power supply unit50further includes a constant-current circuit68, an AC/DC converter circuit70, a battery72and a power changing-over switch SW1. The power supply unit50can select and use a commercial AC power supply or a built-in battery72as a power supply. The power supply to be used can be changed over by an operation input from the operating portion56. If the operation input for changing over the power supply is performed from the operating portion56, the power changing-over switch SW1is controlled by the controlling circuit54so as to change over the power supply to be used.

The AC/DC converter circuit70converts an AC output from the commercial AC power supply to a DC output in the case of using the commercial AC power supply as the power supply. The kind of the battery72may be either a primary battery or a secondary battery. In the case of using the battery72built into the power supply unit50as the power supply, it has an advantage of good portability.

The constant-current circuit68supplies a constant current to the energization pads34of the flexible board20via the power supply probes52. The current supplied from the constant-current circuit68may be either a direct current or an alternating current. The constant-current circuit68can supply a constant current to the electrothermal pattern28irrespective of the size of a load between the energization pads34. For this reason, a calorific value per unit length of the electrothermal pattern28can always be the same irrespective of the length of the electrothermal pattern28of the flexible board20. Therefore, it is possible, by optimizing the current value supplied from constant-current circuit68, to evenly heat the connection pattern24irrespective of the area of the connection pattern24on the flexible board20so as to maintain quality of the soldering.

The power supply probes52are connected with wirings76for detecting the voltage between the energization pads34. The controlling circuit54detects a voltage value applied between the two energization pads34, that is, applied to the electrothermal pattern28based on a voltage detecting signal inputted via the wirings76. The detected voltage value is mainly used to detect a short circuit, a bad connection and the like.

The controlling circuit54sets the current value supplied from the constant-current circuit68to the power supply probes52and exerts on/off control over a current output. The controlling circuit54also includes a timer74, and exerts the on/off control over the current output according to a count value of the timer74so as to control the energization time to the electrothermal pattern28.

The current value supplied to the energization pads34, the energization time and the like are set by the operation input from the operating portion56. It is possible to store the current value, energization time and the like set by the operating portion56in the storage portion60. It is thereby possible to use the current value, energization time and the like stored in the storage portion60on energization next time.

The current value supplied to the energization pads34, the energization time and the like may be automatically set based on a heating profile stored in the external storage medium62or the like. Here, the heating profile is the current value or voltage value supplied to the energization pads34of the flexible board20and the energization time or the data on temporal change in the current value or voltage value, which is set according to the kind of the flexible board20. The heating profile is calculated based on a difference in the calorific value according to the thickness, material and the like of the flexible board20and the pattern width, thickness, material and the like of the electrothermal pattern28, and further based on components of the solder26used to connect the connection patterns14and24, and the like.

When supplying the current to the electrothermal pattern28by using the heating profile, the kind of the flexible board20is specified by the operating portion56first. The controlling circuit54reads the heating profile corresponding to the specified flexible board20out of the external storage medium62. It is thereby possible to set optimal current value and energization time for heating the electrothermal pattern28.

A procedure for specifying the kind of the flexible board20can be as follows for instance. For instance, the flexible board20is given a unique identification sign (such as an ID number). On detecting that the heating start switch of the operating portion56is on, the controlling circuit54causes the display portion58to display an input acceptance screen for the identification sign of the flexible board20. Next, the controlling circuit54determines the kind of the flexible board20based on the identification sign inputted by the operating portion56so as to read out the corresponding heating profile. The flexible board20may be given a barcode, a two-dimensional code or the like instead of the identification sign. And an apparatus for reading the barcode or the two-dimensional code may be mounted on the power supply unit50to read the barcode or the two-dimensional code and thereby specify the kind of the flexible board20.

The heating profile may also be stored in the storage portion60built into the power supply unit50instead of the external storage medium62. The data such as the heating profile is mutually readable and writable between the storage portion60and the external storage medium62. Furthermore, the data such as the heating profile is also mutually readable and writable between the storage portion60and the external device66(such as a PC).

[Processing Flow of the Power Supply Unit]

Next, a processing flow of the controlling circuit54on energization will be described with reference toFIG. 10. First, the flexible board20is inserted into the board insertion opening10A of the multilayer board10, and positioning is performed so that the connection patterns14and24become opposed (overlapping) so as to mount the power supply probes52on the energization pads34of the flexible board20. If the controlling circuit54detects that the power switch of the operating portion56is on (step S10) and the heating start switch for starting a current output of the constant-current circuit68is further on (step S12), it displays the acceptance screen for specifying the kind of the flexible board20on the display portion58. On accepting the specification of the kind of the flexible board20, the controlling circuit54determines whether or not there is the heating profile corresponding to the kind of the flexible board20specified by the external storage medium62or the like (step S14). In the case where there is the heating profile corresponding to the specified kind of the flexible board20(step S14: Yes), the controlling circuit54reads out the heating profile and sets the current value to be supplied to the electrothermal pattern28and energization time based on the read heating profile (step S16). In the case where the kind of the flexible board20is not inputted to the acceptance screen or in the case where there is no heating profile corresponding to the specified kind of the flexible board20(step S14: No), it displays a setting screen for setting the current value to be supplied to the electrothermal pattern28and energization time so as to set the current value to be supplied to the electrothermal pattern28and energization time based on a manual operation from the operating portion56(step S18).

On detecting that the heating start switch is on (step S12), the controlling circuit54outputs a feeble current for examining the electrothermal pattern28from the constant-current circuit68(step S20) so as to detect the voltage value applied to the electrothermal pattern28. In the case where the detected voltage value is larger than an upper limit default (step S22: No), the connection of the electrothermal pattern28is insufficient and may be in an open state, and so the controlling circuit54displays a bad connection warning message on the display portion58(step S24) and stops the current output (step S34). Even if the detected voltage value is equal to or smaller than the predetermined upper limit (step S22: Yes), there is a possibility that the electrothermal pattern28is in a short state in the case where the value is smaller than a predetermined lower limit (step S26: No). Therefore, the controlling circuit54displays a short defect warning message on the display portion58(step S28) and stops the current output (step S34).

In the case where the detected voltage value is equal to or smaller than the predetermined upper limit (step S22: Yes) and equal to or larger than the predetermined lower limit (step S26: Yes), the controlling circuit54outputs the current from the constant-current circuit68according to the current value and energization time set in the step S16or S18(step S30). Thus, the solder26applied to the surfaces of the connection pattern24and the energization pads34of the flexible board20is melted. And if the set energization time elapses (step S32: Yes), the controlling circuit54stops the current output (step S34). Thus, the solder26applied to the surface of the connection pattern24of the flexible board20naturally dissipates heat and coagulates so that connections are made between the connection patterns14and24and the reinforcing pads18and30respectively.

The predetermined upper limit and predetermined lower limit of the steps S22and S26may also be set according to the set kind of the flexible board20. It may also be regularly checked whether or not the voltage value is in a predetermined range of values by detecting the voltage value during the output of the current in the step S30.

When separating the multilayer board10from the flexible board20, the processing from the step S10to S32should be performed in the state where the multilayer board10and the flexible board20are connected. And the flexible board20should be pulled out of the board insertion opening10A of the multilayer board10to stop supplying the current at a stage where the solder26is sufficiently heated and melted (step S34).

Another Embodiment of the Heating Profile

In the example shown inFIG. 10, a set constant current is outputted for a set energization time. However, it is also possible to set a heating profile i (t) for temporally changing the current value in the set energization time for instance. For instance, a current value i is changed stepwise by a unit time t1, (several seconds to several tens of seconds for instance) as shown inFIG. 11.

FIG. 12is a flowchart showing the processing flow of the controlling circuit54of the power supply unit50in the case of using the heating profile shown inFIG. 11. First, the flexible board20is inserted into the board insertion opening10A of the multilayer board10, and positioning is performed so that the connection patterns14and24become opposed (overlapping) so as to mount the power supply probes52on the energization pads34of the flexible board20. If the controlling circuit54detects that the power switch of the operating portion56is on (step S40) and the heating start switch for starting a current output of the constant-current circuit68is further on (step S42), it displays the acceptance screen for specifying the kind of the flexible board20on the display portion58. On accepting the specification of the kind of the flexible board20, the controlling circuit54determines whether or not there is the heating profile corresponding to the kind of the flexible board20specified by the external storage medium62or the like (step S44). In the case where the kind of the flexible board20is not inputted to the acceptance screen or in the case where there is no heating profile corresponding to the specified kind of the flexible board20(step S44: No), it displays a setting screen for setting the current value to be supplied to the electrothermal pattern28and energization time so as to set the current value to be supplied to the electrothermal pattern28and energization time based on a manual operation from the operating portion56(step S46). A description will be omitted as to the processing from the step S46onward because it is the same as the steps S18to S34ofFIG. 10described above.

In the case where there is the heating profile corresponding to the specified kind of the flexible board20(step S44: Yes), the controlling circuit54reads out the heating profile (refer toFIG. 11) and sets the current value to be supplied to the electrothermal pattern28and energization time based on the read heating profile (step S48). It also resets the count value of the timer74of the controlling circuit54(t=0, step S50) and starts counting with the timer74.

Next, the controlling circuit54outputs a feeble current for examining the electrothermal pattern28from the constant-current circuit68(step S52) so as to detect the voltage value applied to the electrothermal pattern28. In the case where the detected voltage value is out of the predetermined range (step S54: No), the connection of the electrothermal pattern28may be insufficient and in an open state or the electrothermal pattern28may be in a short state, and so the controlling circuit54displays a bad connection or a short defect warning message on the display portion58according to the detected voltage value and stops the current output (step S64).

In the case where the detected voltage value is within the predetermined range (step S54: Yes), the controlling circuit54sets a current value i (t) at a current time t based on the heating profile i (t) ofFIG. 10and outputs the current from the constant-current circuit68(step S58). If the predetermined unit time t1, elapses (step S60: Yes), the count time by the timer74becomes t=t+t1(step S62) so as to return to the step S54. The processing from the steps S54to S62is repeated until the count time reaches a final value tendof the heating profile i (t) (step S56: No) to stop the current output (step S64). Thus, the solder26applied to the surfaces of the connection patterns24and the reinforcing pads30of the flexible board20melts and then dissipates heat and coagulates so that connections are made between the connection patterns14and24and the reinforcing pads18and30respectively.

According to the examples shown inFIGS. 11 and 12, the current i is gradually increased to heat and then gradually reduced. Therefore, it is possible to prevent the components and boards of different coefficients of thermal expansion from drastically expanding and getting damaged due to a drastic temperature change. It is also possible to adjust melting and coagulation of the solder26to an ideal state by optimizing the heating profile.

When separating the multilayer board10from the flexible board20, the processing from the steps S40to S62should be performed in the state where the multilayer board10and the flexible board20are connected. And the flexible board20should be pulled out of the board insertion opening10A of the multilayer board10to stop supplying the current stepwise at a stage where the solder26is sufficiently heated and melted (steps S54to S64).

Second Embodiment of the Flexible Board

FIGS. 13A and 13Bare diagrams showing the electrothermal pattern according to a second embodiment of the present invention.FIG. 13Ais a plan view whileFIG. 13Bis a sectional view. Hereunder, the same configurations asFIG. 3described above are given the same symbols, and a description thereof will be omitted.

The flexible board20of this embodiment has a solder smoothing electrothermal pattern40formed on the surface of the side where the connection patterns24and the reinforcing pads30of the flexible board20are placed.

The solder smoothing electrothermal pattern40is used to smooth irregularities of the surface of the solder26attached to the surfaces of the connection patterns14and the reinforcing pads18of the multilayer board10in the case where the multilayer board10is repeatedly connected with and separated from the flexible board20.

As shown inFIG. 13A, the solder smoothing electrothermal pattern40is placed on the insertion end side of the flexible board20to pass the corresponding connection patterns14and reinforcing pads18on the multilayer board10side earlier than the connection patterns24and the reinforcing pads30when the flexible board20is inserted into the board insertion opening10A of the multilayer board10. The solder smoothing electrothermal pattern40should desirably be in a flat form, and may be projected from the surface of the flexible board20further than the connection patterns14and reinforcing pads18.

As shown inFIG. 13A, the solder smoothing electrothermal pattern40is connected to the wiring patterns32or the energization pad34via wiring patterns42. The wiring patterns32or the energization pads34are electrically connected with the wiring patterns42by a through hole for instance. The wiring patterns42are patterns of which calorific value by energization is small (such as a pattern consisting of a material of low electrical resistance or a copper foil pattern) as with the wiring patterns32.

When connecting the multilayer board10with the flexible board20according to this embodiment, the power supply probes52are mounted on the energization pads34of the flexible board20before inserting the flexible board20into the board insertion opening10A. And the processing ofFIG. 10or12described above is performed to energize and heat the electrothermal patterns28and40in advance.

Next, the flexible board20is inserted into the board insertion opening10A of the multilayer board10, and positioning is performed so that the connection patterns14and24become opposed (overlapping) while melting and smoothing the solder26attached to the surfaces of the connection patterns14and the reinforcing pads18with the heat from the solder smoothing electrothermal pattern40. And if the supply of the current to the electrothermal pattern28is stopped, the solder26dissipates heat and coagulates so that connections are made between the connection patterns14and24and the reinforcing pads18and30respectively.

According to this embodiment, it is possible to smooth the irregularities on the surface of the solder26attached to the surfaces of the connection patterns14and the reinforcing pads18of the multilayer board10by inserting the flexible board20into the board insertion opening10A in the state where the solder smoothing electrothermal pattern40is energized and heated. Thus, secure soldering becomes possible.

According to this embodiment, when separating the multilayer board10from the flexible board20, the flexible board20is pulled out while the electrothermal patterns28and40are in a heated state. Therefore, it is possible to smooth the solder26attached to the surfaces of the connection patterns14and the reinforcing pads18of the multilayer board10.

In the example shown inFIGS. 13A and 13B, the current is supplied to the electrothermal patterns28and40from the shared energization pads34. However, the energization pads may also be provided separately to the electrothermal patterns28and40. It is thereby possible to individually heat the electrothermal patterns28and40. Therefore, when inserting the flexible board20into the board insertion opening10A for instance, it is possible to heat only the solder smoothing electrothermal pattern40and then heat the electrothermal pattern28by the processing ofFIG. 10or12after positioning the multilayer board10and the flexible board20.

EXAMPLE OF THERMALLY EXPANDING THE FLEXIBLE BOARD20

To securely connect the connection patterns14and24in the embodiment, it is desirable to press the connection patterns24against the connection patterns14on the multilayer board10side with a certain level of pressure when the electrothermal pattern28is heated by energization.

FIG. 14is a sectional view showing an example in which the flexible board20is provided with a region to be expanded by heat. As shown inFIG. 14, an insert20A to be inserted into the multilayer board10of the flexible board20is formed by a board material having powder of ceramics of a high heat expansion coefficient synthesized, which is thermally expanded by heating of the electrothermal patterns28and40. The thermal expansion of the flexible board20presses the connection patterns24against the connection patterns14on the multilayer board10. Thus, the connection patterns14and24are securely soldered.

A high-heat expanding member should be applied at least to the range including the connection patterns24and the solder smoothing electrothermal pattern40. It is also possible to render the insert20A of the flexible board20as a ceramics board of a high heat expansion coefficient and render an exposed portion20B not to be inserted into the board insertion opening10A as a flexible board which is bendable.

FIG. 15is a sectional view showing an example in which the flexible board20as a multilayer board is provided with a region to be expanded by heat. In the example shown inFIG. 15, the flexible board20is configured by sticking the two boards20-1and20-2together. A plate-like high-heat expanding member80A is attached to the outer surface (the backside of the surface stuck together) of the first layer20-1. A high-heat expanding member80B is attached between the first layer20-1and the second layer20-2at the position corresponding to the solder smoothing electrothermal pattern40. The high-heat expanding members80A and80B are formed by materials of a high heat expansion coefficient like metals such as copper, aluminum or iron or patterns formed by such metals, ceramics and the like.

If the electrothermal patterns28and40are heated by energization, the high-heat expanding members80A and80B expand so that the solder smoothing electrothermal pattern40gets closer to the connection patterns14. It is thereby possible to securely smooth the solder26attached to the connection patterns14with the solder smoothing electrothermal pattern40. Furthermore, as the connection patterns24are pressed against the connection patterns14, it is possible to securely solder the connection patterns14and24.

Third Embodiment of the Flexible Board

FIGS. 16A and 16Bare diagrams showing the flexible board according to a third embodiment of the present invention.FIG. 16Ais a plan view whileFIG. 16Bis a sectional view. Hereunder, the same configurations asFIGS. 13A and 13Bdescribed above are given the same symbols, and a description thereof will be omitted.

As shown inFIGS. 16A and 16B, a flexible board20′ of this embodiment has an IC tag (RFID tag)90mounted thereon. The above described data on the heating profile is stored in the IC tag90.

FIG. 17is a block diagram showing the main configuration of the power supply unit corresponding to the flexible board according to the third embodiment. Hereunder, the same configurations asFIGS. 13A,13B and9described above are given the same symbols, and a description thereof will be omitted.

As shown inFIG. 17, a power supply unit50′ includes an IC tag sending and receiving portion92and an IC tag sending and receiving circuit94. The IC tag sending and receiving portion92includes an antenna for performing radio communication with the IC tag90mounted on the flexible board20. The IC tag sending and receiving circuit94wirelessly supplies operating power to the IC tag90via the IC tag sending and receiving portion92, and also transmits a heating profile read signal. The IC tag90transmits the data on the heating profile to the IC tag sending and receiving portion92according to the read signal. The IC tag sending and receiving circuit94decodes the data on the heating profile received via the IC tag sending and receiving portion92, and outputs it to the controlling circuit54. The controlling circuit54controls the supply of the current from the constant-current circuit68based on the heating profile outputted from the IC tag sending and receiving circuit94.

As shown inFIG. 17, the IC tag sending and receiving portion92is mounted on or around the power supply probe52. For this reason, the IC tag90on the flexible board20side should desirably be mounted in proximity to the energization pads34. It is thereby possible to send and receive the data between the IC tag sending and receiving portion92and the IC tag90in the state where the power supply probes52are mounted on the energization pads34. To be more specific, the IC tag90should be placed in the range capable of sending and receiving in the state where the power supply probes52are mounted on the energization pads34.

The IC tag sending and receiving portion92may be furnished independently from the power supply probes52.

[Processing Flow of the Power Supply Unit]

Next, the processing flow of the controlling circuit54of the power supply unit50′ will be described with reference toFIG. 18. First, the flexible board20is inserted into the board insertion opening10A of the multilayer board10, and positioning is performed so that the connection patterns14and24become opposed (overlapping) so as to mount the power supply probes52on the energization pads34of the flexible board20. If the controlling circuit54detects that the power switch of the operating portion56is on (step S70) and the heating start switch for starting the current output of the constant-current circuit68is further on (step S72), the operating power is wirelessly supplied to the IC tag90from the IC tag sending and receiving portion92, and a detection signal for detecting the IC tag90is transmitted (step S74). In the case where the IC tag90is mounted on the flexible board20, the IC tag90transmits a reply signal in response to the detection signal. The controlling circuit54detects the IC tag90by use of the reply signal received from the IC tag sending and receiving portion92.

Next, if the controlling circuit54detects that there is the heating profile in the IC tag90(step S76: Yes), it reads the heating profile in the IC tag90(step S78) and sets the current value to be supplied to the electrothermal pattern28and energization time based on the read heating profile (step S80). In the case where the IC tag90is not detected by the detection signal or in the case where the heating profile is not detected in the IC tag90(step S76: No), the controlling circuit54subsequently displays the acceptance screen for specifying the kind of the flexible board20on the display portion58. On accepting the specification of the kind of the flexible board20, the controlling circuit54determines whether or not there is the heating profile corresponding to the kind of the flexible board20specified by the external storage medium62or the like (step S82). In the case where there is the heating profile corresponding to the specified kind of the flexible board20(step S82: Yes), the controlling circuit54reads out the heating profile and sets the current value to be supplied to the electrothermal pattern28and energization time based on the read heating profile (step S80).

In the case where the kind of the flexible board20is not inputted to the acceptance screen or in the case where there is no heating profile corresponding to the specified kind of the flexible board20(step S82: No), it displays the setting screen for setting the current value to be supplied to the electrothermal pattern28and energization time so as to set the current value to be supplied to the electrothermal pattern28and energization time based on the manual operation from the operating portion56(step S84).

Next, the controlling circuit54outputs a feeble current for examining the electrothermal pattern28from the constant-current circuit68(step S86) so as to detect the voltage value applied to the electrothermal pattern28(step S88). In the case where the detected voltage value is out of the predetermined range (step S88: No), the connection of the electrothermal pattern28may be insufficient and in an open state or the electrothermal pattern28may be in a short state, and so the controlling circuit54displays a bad connection or a short defect warning message on the display portion58according to the detected voltage value and stops the current output (step S94).

In the case where the detected voltage value is within the predetermined range (step S88: Yes), the controlling circuit54outputs the current from the constant-current circuit68by the current value and energization time set in the step S80or S84(step S90) so as to return to the processing of the step S88. Thus, the solder26applied to the surfaces of the connection patterns24and the reinforcing pads30of the flexible board20melts. And if the set energization time elapses (step S92: Yes), it stops the current output (step S94). Thus, the solder26applied to the surfaces of the connection patterns24of the flexible board20naturally dissipates heat and coagulates so that connections are made between the connection patterns14and24and the reinforcing pads18and30respectively.

According to this embodiment, the heating profile can be automatically set by the power supply unit50′. Therefore, there is an advantage that, in the case where the heating profile of each kind of the flexible board20is different, trouble of setting the heating profile (such as inputting the identification sign of the flexible board20) can be saved to improve operability. Furthermore, it is possible to avoid errors in setting the heating profile.

When separating the multilayer board10from the flexible board20, the processing from the step S70to S92should be performed in the state where the multilayer board10and the flexible board20are connected. And the flexible board20should be pulled out of the board insertion opening10A of the multilayer board10to stop supplying the current at the stage where the solder26is sufficiently heated and melted (step S94).

The range of the detected voltage value of the step S88may also be set according to the set kind of the flexible board20. It may also be regularly checked whether or not the voltage value is in the predetermined range of values by detecting the voltage value during the output of the current in the step S90.

This embodiment is also applicable to the flexible board including the heating profile i (t) shown inFIGS. 11 and 12which is temporally changing and the solder smoothing electrothermal pattern40for smoothing the solder26attached to the connection patterns14and the reinforcing pads18.

Fourth Embodiment of the Flexible Board

FIGS. 19A and 19Bare diagrams showing the flexible board according to a fourth embodiment of the present invention.FIG. 19Ais a plan view whileFIG. 19Bis a sectional view. Hereunder, the same configurations asFIGS. 2A and 2Bdescribed above are given the same symbols, and a description thereof will be omitted.

As shown inFIG. 19, a multilayer board100is configured by sticking three boards100-1,100-2and100-3together in order. As with the above embodiment, a part of the second layer100-2is notched and has a board insertion opening100A for inserting a flexible board200formed thereon.

As shown inFIGS. 19A and 19B, the first layer100-1of the multilayer board100has a beam introduction opening102formed thereon correspondingly to the positions of the connection patterns24on inserting the flexible board200. As shown inFIG. 19B, the beam introduction opening102penetrates the first layer100-1from its surface to the board insertion opening100A. The beam introduction opening102should be of a size not intercepting a laser beam.

In the case of connecting the multilayer board100with the flexible board200, the flexible board200is inserted into the board insertion opening100A of the multilayer board100first as shown inFIG. 19B, and positioning is performed so that the connection patterns14and24become opposed (overlapping). In this case, the connection patterns14,24and the beam introduction opening102are arranged in alignment. Next, the laser beam is radiated from a beam radiation opening302of300(refer toFIG. 22) via the beam introduction opening102. The radiated laser beam transmits through the flexible board200to reach the connection patterns24. And then the connection patterns24are heated so that the solder applied to the surfaces of the connection patterns24is melted. And if the radiation of the laser beam is stopped, the solder dissipates heat and coagulates. The connection patterns14and24are connected via the solder28, and the wiring patterns formed on the multilayer board100and the flexible board200are electrically connected.

In the case of separating the multilayer board100from the flexible board200, the radiation of the laser beam is started first in the state where the multilayer board100and the flexible board200are connected (refer toFIG. 19B). The solder connecting the connection patterns14with the connection patterns24is melted. Next, the flexible board200is pulled out of the board insertion opening100A of the multilayer board100. Thus, the multilayer board100is separated from the flexible board200.

Fifth Embodiment of the Flexible Board

FIGS. 20A and 20Bare diagrams showing the flexible board according to a fifth embodiment of the present invention.FIG. 20Ais a plan view whileFIG. 20Bis a sectional view. Hereunder, the same configurations asFIGS. 19A and 19Bdescribed above are given the same symbols, and a description thereof will be omitted.

In the example shown inFIG. 20B, the flexible board200of this embodiment is configured by sticking two boards200-1and200-2together. A highly heat-conductive member202of which coefficient of thermal conductivity is high is formed between the first layer200-1and the second layer200-2of the flexible board200. The highly heat-conductive member202is formed by materials of a high coefficient of thermal conductivity like metals such as copper, aluminum or iron or patterns and the like formed by such metals. The highly heat-conductive member202should desirably be placed to cover the area where the connection patterns24are formed.

As shown inFIG. 20A, the multilayer board100of this embodiment has one beam introduction opening102formed thereon. The beam introduction opening102is formed approximately at the center position of the highly heat-conductive member202when the flexible board200is inserted into the board insertion opening100A.

According to this embodiment, the highly heat-conductive member202is radiated with the laser beam and heated via the beam introduction opening102. And the solder applied to the surfaces of the connection patterns24is melted by the heat conducted from the highly heat-conductive member202.

According to this embodiment, the connection patterns24can be mounted on both sides of the flexible board200.

In the case where the highly heat-conductive member202includes a conductive substance such as a copper foil pattern, it is desirable to ground the highly heat-conductive member202. It is thereby possible to reduce the effects of the noise generated on operation of the circuit.

InFIGS. 19A,19B,20A, and20B the wiring patterns formed on the multilayer board100and the flexible board200are omitted in order to avoid complication of the drawings.

In the case where the central portion of the highly heat-conductive member202is heated, temperature of the central portion becomes higher than that in a surrounding part. Thus, there is a tendency that the temperature of the surrounding part lowers first in the cased where the heating is stopped. Therefore, the coagulation of the solder applied to the connection patterns24starts from the connection patterns24equivalent to the surrounding part of the highly heat-conductive member202. The closer to the central portion the connection patterns24are, the slower the coagulation of the solder becomes. For this reason, it is desirable that the area of the surrounding part of the highly heat-conductive member202be larger than the area of its central portion as shown inFIG. 21. Thus, the temperature of the whole area can be uniformized by extending heat storage time after stopping the heating. As the coagulation of the solder does not become even, a stress is applied to the flexible board200so that twisting and lifting are apt to occur to avoid defective soldering.

In the examples shown inFIGS. 20A,20B and21, it is possible to use a high-heat expanding member which is highly heat-conductive and highly heat-expanding as the highly heat-conductive member202. It is also possible, as in the example shown inFIG. 14, to configure the inserting portion of the flexible board200by including the high-heat expanding member. It is thereby possible, as in the examples shown inFIGS. 14 and 15, to press the connection patterns24against the connection patterns14so as to allow secure soldering.

It is also possible to provide the wiring board of this embodiment with the reinforcing pads18,30and the solder smoothing electrothermal pattern40described above.

Embodiment of the Wiring Board Connecting Apparatus (Laser Emission Unit)

FIG. 22is a block diagram showing the main configuration of a laser emission unit300. As shown inFIG. 22, the laser emission unit300includes a controlling circuit304, an operating portion306, a display portion308, a storage portion310, an external storage medium312and an external connecting terminal314.

The controlling circuit304is a control portion for integrally controlling the laser emission unit300. The controlling circuit304controls the operation of the laser emission unit300based on signal inputs from the operating portion306and the like. The operating portion306includes a power switch of the laser emission unit300, a heating start switch for starting the radiation of the laser beam from a beam radiation opening302and various other operating switches. The display portion308is a monitor for displaying various operation menus and set contents and also displaying a warning. The storage portion310is an apparatus for storing data, programs and the like necessary to control the laser emission unit300, which is a memory (a non-volatile memory for instance) built into the laser emission unit300for instance. The external storage medium312is a storage medium detachable from the power supply unit50, which is a semiconductor memory such as a memory card, an optical disk such as a CD or a DVD or a magnetic disk such as an HDD for instance. The external connecting terminal314is an interface for communication with an external device316(such as a personal computer), which is a USB for instance.

Next, the power supply of the laser emission unit300will be described. As shown inFIG. 22, the laser emission unit300further includes an AC/DC converter circuit318, a battery320and a power changing-over switch SW2. The laser emission unit300can select and use a commercial AC power supply or the built-in battery320as the power supply. The power supply to be used can be changed over by an operation input from the operating portion306. If the operation input for changing over the power supply is performed from the operating portion306, the power changing-over switch SW2is controlled by the controlling circuit304so as to change over the power supply to be used.

The AC/DC converter circuit318converts an AC input from the commercial AC power supply to a DC input in the case of using the commercial AC power supply as the power supply. The kind of the battery320may be either a primary battery or a secondary battery. In the case of using the battery320built into the laser emission unit300as the power supply, it has an advantage of good portability.

Next, a description will be given as to a control system for controlling the radiation of the laser beam of the laser emission unit300. As shown inFIG. 22, the laser emission unit300further includes a laser beam emitting portion322, an optical system324, a fiber-optic cable326, an infrared reflection plate328, an infrared acceptance sensor330and a sensor driving circuit332.

The laser beam emitting portion322is an apparatus for emitting the laser beam. The laser beam raised by the laser beam emitting portion322is collected by the optical system324to be guided by the fiber-optic cable326. The beam radiation opening302is formed at the end of the fiber-optic cable326, and is inserted into the beam introduction opening102of the multilayer board100. The laser beam guided via the fiber-optic cable326is radiated on the highly heat-conductive member202or the connection patterns24of the flexible board200so that the solder applied to the surfaces of the connection patterns24is heated and melted.

Light volume, intensity, radiation time and the like of the laser beam radiated on the highly heat-conductive member202or the connection patterns24are set based on heating temperature, heating time and the like set by an operation input from the operating portion306. It is possible to store the heating temperature, heating time and the like set by the operating portion306in the storage portion310. Thus, it is possible to use the current value, energization time and the like stored in the storage portion310on radiation of the laser beam next time.

The light volume, intensity, radiation time and the like of the laser beam radiated on the highly heat-conductive member202or the connection patterns24may also be automatically set based on the heating profile stored in the external storage medium312or the like. Here, the heating profile is the data representing the light volume, intensity and radiation time of the laser beam radiated on the highly heat-conductive member202or the connection patterns24of the flexible board200, temporal change thereof or a correlation with temperature change of the highly heat-conductive member202or the connection patterns24, which is set according to the kind of the flexible board200. The heating profile is calculated based on a difference in the calorific value according to the thickness, material and the like of the flexible board200and the pattern width, thickness, material and the like of the connection patterns24, and further based on the components of the solder used to connect the connection patterns14and24, and the like.

When using the heating profile, the kind of the flexible board200is specified by the operating portion306first. The controlling circuit304reads the heating profile corresponding to the specified flexible board200out of the external storage medium312. It is thereby possible to set the optimal light volume, intensity and radiation time of the laser beam for heating the connection patterns24.

The procedure for specifying the kind of the flexible board200can be as follows for instance. For instance, the flexible board200is given a unique identification sign (such as an ID number). On detecting that the heating start switch of the operating portion306is on, the controlling circuit304causes the display portion308to display the input acceptance screen for the identification sign of the flexible board200. Next, the controlling circuit304determines the kind of the flexible board200based on the identification sign inputted by the operating portion306so as to read out the corresponding heating profile. The flexible board200may be given a barcode, a two-dimensional code or the like instead of the identification sign. And an apparatus for reading the barcode or the two-dimensional code may be mounted on the laser emission unit300to read the barcode or the two-dimensional code and thereby specify the kind of the flexible board200.

The heating profile may also be stored in the storage portion310built into the laser emission unit300instead of the external storage medium312. The data such as the heating profile is mutually readable and writable between the storage portion310and the external storage medium312. Furthermore, the data such as the heating profile is also mutually readable and writable between the storage portion310and the external device316(such as a PC).

The highly heat-conductive member202or the connection patterns24radiates infrared light by heating. The infrared light enters the infrared reflection plate328via the fiber-optic cable326. The infrared reflection plate328is a transparent member such as glass IR-coated on the fiber-optic cable326side for instance, which transmits the laser beam and reflects the infrared light so that the infrared light having entered the infrared reflection plate328is reflected to be received by the infrared acceptance sensor330.

The infrared acceptance sensor330outputs the electrical signal to the sensor driving circuit332according to the light volume of the received infrared light. The sensor driving circuit332drives the infrared acceptance sensor330and amplifies the electrical signal outputted from the infrared acceptance sensor330to send it to the controlling circuit304.

The controlling circuit304detects the temperature of the highly heat-conductive member202or the connection patterns24based on the light volume of the received infrared light. And the controlling circuit304exerts feedback control for adjusting the intensity, light volume, radiation time or the like of the laser beam so that the temperature of the highly heat-conductive member202or the connection patterns24becomes the set temperature.

The storage portion310or the external storage medium312stores correlation table data on the infrared light volume versus the temperature created by measuring the correlation between the infrared light volume received via the fiber-optic cable326and the temperature of the highly heat-conductive member202or the connection patterns24in advance. The controlling circuit304can easily acquire the temperature of the highly heat-conductive member202or the connection patterns24from the infrared light volume by referring to the correlation table data. The temperature of the highly heat-conductive member202or the connection patterns24may also be calculated by a formula representing the correlation between the infrared light volume and the temperature.

The infrared reflection plate328is provided to be movable, and its position is controlled by the controlling circuit304. In the case of exerting open-loop control without measuring the temperature of the highly heat-conductive member202or the connection patterns24, the infrared reflection plate328is moved to the position of reference numeral328′ in the drawing. In the case of exerting the open-loop control as above, the infrared reflection plate328is moved out of a light path of the laser beam so that the loss of the radiated laser beam guided by the fiber-optic cable326from the optical system324can be reduced.

According to this embodiment, the laser beam is used to heat the highly heat-conductive member202or the connection patterns24of the flexible board200. It is also possible, however, to use the light other than the laser beam or the beam for heating such as an electron beam or an ion beam.

According to this embodiment, the light volume of the infrared light is measured to detect the temperature of the highly heat-conductive member202or the connection patterns24. It is also possible, however, to mount a temperature sensor around the beam radiation opening302for instance.

In the case where the area of the highly heat-conductive member202or the connection patterns24is larger than the bore of the beam radiation opening302, it is desirable to allow the laser beam to be radiated in a wider range.FIG. 23is a diagram showing the beam radiation opening302by enlarging it. As shown inFIG. 23, the beam radiation opening302is formed by shaping the end of the fiber-optic cable326like a concave face, a lens, a convex face or a polyhedron. It is thereby possible to expand the area to be radiated with the laser beam on the highly heat-conductive member202or the connection patterns24. It is also possible, by diffusing the laser beam, to realize more even heating which is hardly concentrated. Furthermore, shaping the end of the fiber-optic cable326in the above form has the effects of allowing the infrared light radiated from the highly heat-conductive member202or the connection patterns24to be collected from a wider range and securing detection accuracy of the temperature even in the case where the radiated infrared light is uneven.

According to this embodiment, it is also possible, as with the above embodiment, to provide the IC tag90on the flexible board200and also provide the IC tag sending and receiving portion92and IC tag sending and receiving circuit94on the laser emission unit300so as to perform the setting of the heating profile.

[Processing Flow of the Laser Emission Unit]

Next, the processing flow of the controlling circuit304of the power supply unit300will be described with reference toFIG. 24. First, the flexible board200is inserted into the board insertion opening100A of the multilayer board100. And the positioning is performed so that the connection patterns14and24become opposed (overlapping) while the beam radiation opening302is inserted into the beam introduction opening102of the multilayer board100. If the controlling circuit304detects that the power switch of the operating portion306is on (step S100) and the heating start switch for starting the radiation of the laser beam is further on (step S102), it displays the acceptance screen for specifying the kind of the flexible board200on the display portion308. The multilayer board100and flexible board200are is identifiable by the identification signs, one-dimensional codes, two-dimensional codes and the like as with the above embodiment. On accepting the specification of the kind of the flexible board200, the controlling circuit304determines whether or not there is the heating profile corresponding to the kind of the flexible board200specified by the external storage medium312or the like (step S104). In the case where there is the heating profile corresponding to the specified kind of the flexible board200(step S104: Yes), the controlling circuit304reads out the heating profile and sets the heating temperature and heating time of the highly heat-conductive member202or the connection patterns24based on the read heating profile (step S106). In the case where the kind of the flexible board200is not inputted to the acceptance screen or in the case where there is no heating profile corresponding to the specified kind of the flexible board200(step S104: No), it displays the setting screen for setting the heating temperature and heating time of the highly heat-conductive member202or the connection patterns24so as to set the heating temperature and heating time of the highly heat-conductive member202or the connection patterns24based on the manual operation from the operating portion306(step S108).

Next, the controlling circuit304outputs a predetermined volume of the laser beam, measures the infrared light volume radiated from the highly heat-conductive member202or the connection patterns24of the flexible board200and detects the temperature of the highly heat-conductive member202or the connection patterns24(step S110). If the temperature detected in the step S110(detected temperature) is equal to or lower than the set temperature (step S112: No), it increases the volume of the laser beam by the predetermined volume (step S114). If the detected temperature is higher than the set temperature (step S112: Yes), it reduces the volume of the laser beam by the predetermined volume (step S116). The predetermined volume in the steps S114and S116may be constant. It is also possible, however, to calculate the volume of the laser beam and the radiation time to be the set temperature based on the detected infrared light volume and the current volume of the laser beam so as to set the calculated value as the predetermined volume. The controlling circuit304performs the processing of the steps S112to S116every predetermined time (step S120) so as to increase the temperature of the highly heat-conductive member202or the connection patterns24stepwise and maintain it. As for the predetermined time in the steps S120, the time for reaching the range of the set temperature in normal operation is set.

Next, each time the predetermined time elapses (step S120: Yes), it is detected whether or not the detected temperature is within the predetermined range (step S122). If the detected temperature is within the predetermined range (step S122: Yes), it returns to the processing of the step S112. If the detected temperature is out of the predetermined range (step S122: No), that is, if the detected temperature is lower than the predetermined range for instance, it may be assumed that the laser beam is radiated and there is neither highly heat-conductive member202nor the connection patterns24within the range capable of detecting the infrared light. If the detected temperature is higher than the predetermined range, abnormal overheating or the like is assumed. For this reason, the controlling circuit304displays a warning message indicating an abnormal state on the display portion308(step S124), and stops the radiation of the laser beam (step S126). It is thereby possible to prevent the abnormal overheating and the like so as to secure safety.

The processing from the steps S111to S122is repeated until the set heating time of the laser beam elapses (step S118: Yes) to stop the radiation of the laser beam (step S126). Thus, the solder26applied to the surfaces of the connection patterns24of the flexible board200naturally dissipates heat and coagulates so that connections are made between the connection patterns14and24respectively.

When separating the multilayer board100from the flexible board200, the processing from the step S100to S124should be performed in the state where the multilayer board100and the flexible board200are connected. And the flexible board200should be pulled out of the board insertion opening100A to stop the radiation of the laser beam at the stage where the solder connecting the connection patterns14with24is sufficiently heated and melted (step S126).