Heat flow distribution measurement device

A heat flow distribution measurement device includes a sensor module having one multilayer substrate and a plurality of heat flow sensor portions arranged inside of the multilayer substrate. The multilayer substrate has one surface and another surface opposite to the one surface and includes a plurality of stacked insulating layers each formed of a thermoplastic resin. The heat flow sensor portions are each formed of thermoelectric conversion elements and are thermoelectrically independent. An arithmetic portion arithmetically determines a heat flow distribution based on an electromotive force generated in each of the heat flow sensor portions. The thermoelectric conversion elements are formed in the multilayer substrate and therefore manufactured by the same manufacturing process for manufacturing the multilayer substrate. This can minimize the performance difference between the individual thermoelectric conversion elements and allow the heat flow distribution to be measured with high precision.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a U.S. National Phase Application under 35 U.S.C. 371 of International Application No. PCT/JP2015/002742 filed on Jun. 1, 2015 and published in Japanese as WO 2015/186330 A1 on Dec. 10, 2015. This application is based on and claims the benefit of priority from Japanese Patent Application No. 2014-114827 filed on Jun. 3, 2014 and Japanese Patent Application No. 2015-099314 filed on May 14, 2015. The entire disclosures of all of the above applications are incorporated herein by reference.

TECHNICAL FIELD

The present disclosure relates to a heat flow distribution measurement device.

BACKGROUND ART

Examples of a heat flow sensor which senses a heat flow include the one described in Patent Literature 1. The heat flow sensor uses a thermoelectric conversion element. Specifically, a plurality of through holes are formed in an insulating base material and first and second conductive metals as different metal materials are embedded in the plurality of through holes and alternately connected in series.

PRIOR ART LITERATURE

Patent Literature

SUMMARY OF INVENTION

For example, there is a case where it is desired to know in what heat energy (heat flow) distribution a given plate-like heater produces heat. Also, there is a case where it is desired to know the heat release distribution of the heat sink provided on a printed circuit board or the like.

In the case where it is desired to measure the heat flow distribution of a measurement target such as a heater or a heat sink, it can be considered to measure the heat flow distribution using a plurality of the heat flow sensors described above. For example, it can be considered to perform the measurement by placing the plurality of heat flow sensors on the surface of an object to be heated away from the measurement target and attach the plurality of heat flow sensors to the measurement target.

However, the plurality of heat flow sensors manufactured as separate and independent bodies have performance differences therebetween, so it has been difficult to measure the heat flow distribution with high precision.

There is also a method which measures a heat flow distribution using a thermographic device. However, what can be measured by thermography is the distribution of a surface temperature determined from infrared wavelengths. Since the distribution of the surface temperature is not a heat flow distribution, to convert the distribution of the surface temperature to a heat flow distribution, it is necessary to perform analysis by taking various elements into account. Accordingly, by this method also, it is difficult to measure a heat flow distribution with high precision.

An object of the present disclosure is to provide a heat flow distribution measurement device capable of measuring a heat flow distribution with high precision.

According to a first aspect of the present disclosure, a heat flow distribution measurement device includes a sensor module having one multilayer substrate and a plurality of heat flow sensor portions arranged inside of the multilayer substrate. The multilayer substrate has one surface and another surface opposite to the one surface and includes a plurality of stacked insulating layers each formed of a thermoplastic resin. Each of the plurality of heat flow sensor portions is formed of an electrically independent thermoelectric conversion element. When the sensor module is placed with the one surface facing a measurement target of which a heat flow distribution is to be measured, each of the thermoelectric conversion elements produces an electric output in accordance with a heat flow passing through the inside of the multilayer substrate in a direction perpendicular to the one surface.

According to a second aspect of the present disclosure, the heat flow distribution measurement device according to the first aspect further includes an arithmetic portion that arithmetically determines the heat flow distribution on the basis of the electric output produced by each of the plurality of heat flow sensor portions.

In each of the heat flow distribution measurement devices according to the foregoing first and second aspects, the thermoelectric conversion elements forming the respective heat flow sensor portions are formed in the single multilayer substrate and are therefore manufactured by the same manufacturing process for manufacturing the multilayer substrate. This allows the performance difference between the individual thermoelectric conversion elements to be smaller than in the case where a plurality of heat flow sensors are manufactured as separate and independent bodies.

Accordingly, the heat flow distribution can be measured with higher precision than in the case where a heat flow distribution is measured using the plurality of heat flow sensors manufactured as separate and independent bodies.

According to a third aspect of the present disclosure, a heat flow distribution measurement device includes a sensor module having one multilayer substrate and a plurality of heat flow sensor portions arranged inside of the multilayer substrate. The multilayer substrate has one surface and another surface opposite to the one surface and includes a plurality of stacked insulating layers. Each of the plurality of heat flow sensor portions is formed of an electrically independent thermoelectric conversion element. When the sensor module is placed with the one surface facing a measurement target of which a heat flow distribution is to be measured, each of the thermoelectric conversion elements produces an electric output in accordance with a heat flow passing through the inside of the multilayer substrate in a direction extending from one of the one surface and the other surface to the other of the one surface and the other surface.

In the heat flow distribution device according to the third aspect also, for the same reason as given for the heat flow distribution measurement devices according to the first and second aspects, a heat flow distribution can be measured with higher precision than in the case where a heat flow distribution is measured using a plurality of heat flow sensors manufactured as separate and independent bodies.

DESCRIPTION OF EMBODIMENTS

The following will describe the embodiments of the present disclosure on the basis of the drawings. In the following description of the different embodiments, like or equivalent component parts are designated by like reference characters or numerals.

First Embodiment

As shown inFIG. 1, a heat flow distribution measurement device1of the present embodiment includes a sensor module2, an electronic control unit3, and a display unit4.

The sensor module2includes a plurality of integrated heat flow sensor portions10each of which measures a heat flow. The sensor module2has a flat plate shape having one surface2a(first surface) and another surface2b(second surface) opposite thereto (seeFIG. 3). In the present embodiment, the heat flow sensor portions10are arranged in a matrix configuration in directions parallel with the one surface2a. Each of the quadrilaterals shown by the broken lines inFIG. 1shows a portion functioning as one heat flow sensor portion10. As shown inFIG. 1, each of the plurality of heat flow sensor portions10has a length in one direction and a length in another direction perpendicular thereto which are equal to each other. The plurality of heat flow sensor portions10are orderly arranged in the one direction and the other direction. The heat flow sensor portions10in adjacent rows which face each other are at matching positions.

The plurality of heat flow sensor portions10are electrically independent of each other and connected to the electronic control unit3via wiring. Note that, as will be described later, the heat flow sensor portions10correspond to a region of a multilayer substrate where thermoelectric conversion elements connected in series are formed.

The electronic control unit3functions as an arithmetic portion that arithmetically determines a heat flow distribution. The electronic control unit3includes, e.g., a microcomputer, a memory as a storage means, and a peripheral circuit thereof and performs a predetermined arithmetic process in accordance with a preset program. The electronic control unit3arithmetically determines a heat flow distribution of a measurement target on the basis of the result of the sensing of a heat flow by the plurality of heat flow sensor portions10and performs image processing thereon to cause the display unit4to display the heat flow distribution as a two-dimensional image.

The display unit4displays a two-dimensional image of a heat flow distribution. As the display unit4, a typical image display unit can be used.

Also, as shown inFIGS. 2 and 3, the heat flow distribution measurement device1includes a sensor head21on which the sensor module2is placed, a support pillar22which supports the sensor head21, and a stage23on which a measurement target31is placed.

On the lower surface of the sensor head21, the sensor module2is disposed. As a result, the other surface2bof the sensor module2is fixed to the sensor head21and the one surface2aof the sensor module2faces the measurement target31. The support pillar22has a mechanism which allows height adjustment so that the distance between the sensor module2and the measurement target31is adjustable.

Next, a description will be given of a specific structure of the sensor module2. The sensor module2includes the plurality of heat flow sensor portions10each having the same internal structure and formed in one multilayer substrate. Therefore, the following will describe the structure of one of the heat flow sensor portions10.

As shown inFIGS. 4 to 6, one of the heat flow sensor portions10has an insulating base material100, an insulating layer110, a surface protection member115, and a back-surface protection member120which are stacked to be integrated. In the integrated stack, first and second interlayer connection members130and140are alternately connected in series.FIG. 4is a plan view of each one of the heat flow sensor portions10but, for easier understanding, the illustration of the surface protection member115and the insulating layer110is omitted. Also,FIG. 4is not a cross-sectional view but, for easier understanding, the first and second interlayer connection members130and140are hatched.

The insulating base material100is formed of a film made of a thermoplastic resin represented by polyetheretherketone (PEEK), polyetherimide (PEI), a liquid crystal polymer (LCP), or the like. The insulating base material100is formed in a zigzag pattern such that a plurality of first and second via holes101and102extending through the insulating base material100in a thickness direction are staggered with respect to each other. The first and second via holes101and102are through holes extending from one surface100aof the insulating base material100to another surface100bthrough the insulating base material100.

Note that each of the first and second via holes101and102in the present embodiment has a cylindrical shape having a diameter which is uniform in the direction extending from the top surface100ato the back surface100b. However, each of the first and second via holes101and102may have a tapered shape having a diameter which decreases with distance from the top surface100atoward the back surface100b. Alternatively, each of the first and second via holes101and102may have a tapered shape having a diameter which decreases with distance from the back surface100btoward the top surface100aor an angular cylindrical shape.

In the first via holes101, the first interlayer connection members130are disposed while, in the second via holes102, the second interlayer connection members140are disposed. That is, in the insulating base material100, the first and second interlayer connection members130and140are arranged to be staggered with respect to each other.

Since the first and second interlayer connection members130and140are thus disposed in the first and second via holes101and102, by appropriately changing the numbers of the first and second via holes101and102, the diameters thereof, the spaces therebetween, or the like, it is possible to increase the density of the first and second interlayer connection members130and140. This can increase the electromotive force generated in the first and second interlayer connection members130and140alternately arranged in series, i.e., voltage and increase the sensitivity of each of the heat flow sensor portions10.

The first and second interlayer connection members130and140are first and second conductors formed of different conductive materials so as to achieve a Seebeck effect. Examples of the conductive materials include a metal and a semiconductor. For example, each of the first interlayer connection members130is formed of a metal compound obtained by subjecting a Bi—Sb—Te alloy powder showing a P-type conductivity type to solid-phase sintering such that the plurality of metal atoms retain the crystal structures thereof before the sintering. On the other hand, the second interlayer connection member140is formed of a metal compound obtained by subjecting a Bi—Te alloy powder showing an N-type conductivity type to solid-phase sintering such that the plurality of metal atoms retain the crystal structures thereof before the sintering. Thus, the metals forming the first and second interlayer connection members130and140are sintered alloys obtained by sintering the plurality of metal atoms in the state where the metal atoms retain the crystal structures thereof. This can increase the electromotive force generated in each of the first and second interlayer connection members130and140alternately arranged in series and increase the sensitivity of each of the heat flow sensor portions10.

On the top surface100aof the insulating base material100, the insulating layer110is disposed. The insulating layer110is formed of a film made of a thermoplastic resin represented by polyetheretherketone (PEEK), a polyetherimide (PEI), a liquid crystal polymer (LCP), or the like. In the one surface110aof the insulating layer110which faces the insulating base material100, a plurality of top-surface patterns111resulting from the patterning of a copper foil or the like are formed so as to be spaced apart from each other. Each of the top-surface patterns111is electrically connected appropriately to the first and second interlayer connection members130and140.

Specifically, when it is assumed that one of the first interlayer connection members130and one of the second interlayer connection members140which are adjacent to each other form one pair150as shown inFIG. 5, the first and second interlayer connection members130and140in each one of the pairs150are connected to the same top-surface pattern111. That is, the first and second interlayer connection members130and140in each one of the pairs150are electrically connected via the top-surface pattern111. Note that, in the present embodiment, one of the first interlayer connection members130and one of the second interlayer connection members140which are adjacent to each other along one direction (a left and right direction inFIG. 5) form one of the pairs150.

On the back surface110bof the insulating base material100, the back-surface protection member120is disposed. The back-surface protection member120is formed of a film made of a thermoplastic resin represented by polyetheretherketone (PEEK), polyetherimide (PEI), a liquid crystal polymer (LCP), or the like. In the one surface120aof the back-surface protection member120which faces the insulating base material100, a plurality of back-surface patterns121resulting from the patterning of a copper foil or the like are formed so as to be spaced apart from each other. Each of the back-surface patterns121is electrically connected appropriately to the first and second interlayer connection members130and140.

Specifically, as shown inFIG. 5, the first interlayer connection member130in one of the two pairs150adjacent to each other in one direction and the second interlayer connection member140in the other of the two pairs150are connected to the same back-surface pattern121. That is, the first and second interlayer connection members130and140respectively belonging to one and the other of the different pairs150are electrically connected via the same back-surface pattern121.

Also, as shown inFIG. 6, in the end portion of one of the heat flow sensor portions10, the first and second interlayer connection members130and140adjacent to each other along another direction (left-right direction over the surface of the paper sheet withFIG. 4orFIG. 6) orthogonal to the one direction are connected to the same back-surface pattern121.

Thus, the individual pairs150are connected in series and arranged in the multilayer substrate such that a sequence of the pairs150connected in one direction (an up and down direction inFIG. 4) is repeatedly bent back. Note that one pair of the first and second interlayer connection members130and140connected to each other form one thermoelectric conversion element. Accordingly, each one of the plurality of heat flow sensor portions10includes the plurality of thermoelectric conversion elements connected in series. Note that the plurality of heat flow sensor portions10are electrically independent of each other and each one of the plurality of heat flow sensor portions10is electrically connected individually to the electronic control unit3. In the present description, the plurality of thermoelectric conversion elements electrically connected in series to form each one of the heat flow sensor portions10are referred to as an electrically independent thermoelectric conversion element.

On the other surface110bof the insulating layer110, the surface protection member115is disposed. The surface protection member115is formed of a film made of a thermoplastic resin represented by polyetheretherketone (PEEK), polyetherimide (PEI), a liquid crystal polymer (LCP), or the like. As shown inFIG. 6, in the one surface115aof the surface protection member115which faces the insulating layer110, a plurality of wiring patterns116resulting from the patterning of a copper foil or the like are formed. In each one of the heat flow sensor portions10, the wiring patterns116are electrically connected to the end portions of the first and second interlayer connection members130and140connected in series as described above via an interlayer connection member117formed in the insulating layer110.

As shown inFIGS. 7 and 8, the plurality of wiring patterns116extend from the respective positions of the heat flow sensor portions10to the end portions of the sensor module2. As a result, two wires are formed to extend from each one of the heat flow sensor portions10to the end portions of the sensor module2. Note thatFIG. 7is a plan view of the sensor module2from which the surface protection member115has been omitted. However, for easier understanding, the portions of the wiring patterns116which function as connection portions are hatched. As shown inFIG. 6, at the end portions of the sensor module2, parts of the wiring patterns116are exposed. The exposed parts of the wiring patterns116form connection terminals for connecting each one of the heat flow sensor portions10to the electronic control unit3.

Thus, in the present embodiment, the wiring patterns116connected to the individual heat flow sensor portions10are formed in a layer different from the layer in which the first and second interlayer connection members130and140, the top-surface patterns111, and the back-surface patterns121are formed (seeFIG. 7). In the case of using a plurality of heat flow sensors as separate and independent bodies, when the plurality of heat flow sensors are attached to the measurement target, a space where wiring is to be placed is needed between the heat flow sensors adjacent to each other. By contrast, according to the present embodiment, a space where wiring is to be placed is not needed between the heat flow sensors adjacent to each other. This allows the plurality of heat flow sensor portions10to be densely arranged.

The foregoing is the basic configuration of each of the heat flow sensor portions10in the present embodiment. As described above, the thermoelectric conversion elements included in each one of the heat flow sensor portions10include the first and second interlayer connection members130and140which are embedded in the plurality of first and second via holes101and102and alternately connected in series. The first and second interlayer connection members130and140included in each one of the plurality of heat flow sensor portions10are formed in the same insulating base material100.

The plurality of heat flow sensor portions10output respective sensor signals (electromotive forces) in accordance with the temperature difference between the both surfaces of the multilayer substrate to the electronic control unit3. When the temperature difference between the both surfaces changes, the electromotive force generated in the first and second interlayer connection members130and140alternately connected in series changes. This allows heat flows or heat flow fluxes passing through the heat flow sensor portions10to be calculated from the electromotive forces generated in the heat flow sensor portions10.

Referring toFIGS. 9A to 9H, a description will be given of a method of manufacturing the foregoing sensor module2.FIGS. 9A to 9Hshow one of the heat flow sensor portions10and correspond toFIG. 5.

First, as shown inFIG. 9A, the insulating base material100is prepared and the plurality of first via holes101are formed using a drill, a laser, or the like.

Next, as shown inFIG. 9B, each of the first via holes101is filled with a first conductive paste131. Note that, as a method (device) for filling the first via holes101with the first conductive paste131, the method (device) described in Japanese Patent Application No. 2010-50356 (JP 2011-187619 A) filed by the present applicant may be used appropriately.

The following is a brief description thereof. On a holder not shown, the insulating base material100is placed via an adsorption sheet160such that the back surface100bthereof faces the adsorption sheet160. Then, the first conductive paste131is melted, while the first via holes101are filled with the molten conductive paste131. As a result, a major part of the organic solvent of the first conductive paste131is adsorbed by the adsorption sheet160and an alloy powder is placed in direct contact with the first via holes101.

Note that the adsorption sheet160may appropriately be made of a material capable of absorbing the organic solvent of the first conductive paste131. As the adsorption sheet160, a typical high-quality sheet or the like is used. On the other hand, as the first conductive paste131, a paste obtained by adding a Bi—Sb—Te alloy powder in which the metal atoms retain predetermined crystal structures to an organic solvent having a melting point of 43° C., such as paraffin, is used. Accordingly, when the first via holes101are filled with the first conductive paste131, the filling is performed in the state where the top surface100aof the insulating base material100is heated to about 43° C.

Subsequently, as shown inFIG. 9C, the plurality of second via holes102are formed in the insulating base material100using a drill, a laser, or the like. As described above, the second via holes102are staggered with respect to the first via holes101and formed so as to form a zigzag pattern in conjunction with the first via holes101.

Next, as shown inFIG. 9D, each of the second via holes102is filled with a second conductive paste141. Note that the step can be performed in the same step as that inFIG. 9Bdescribed above.

That is, on the holder not shown, the insulating base material100is placed again via the adsorption sheet160such that the back surface100bthereof faces the adsorption sheet160. Then, the second via holes102are filled with the second conductive paste141. As a result, a major part of the organic solvent of the second conductive paste141is adsorbed by the adsorption sheet160and an alloy powder is placed in direct contact with the second via holes102.

As the second conductive paste141, a paste obtained by adding a Bi—Te alloy powder in which the metal atoms different from those included in the first conductive paste131retain predetermined crystal structures to an organic solvent having a melting point in the room temperature range, such as terpineol, is used. That is, as the organic solvent included in the second conductive paste141, an organic solvent having the melting point lower than that of the organic solvent included in the first conductive paste131is used. When the second via holes102are filled with the second conductive paste141, the filling is performed in the state where the top surface100aof the insulating base material100is held at a room temperature. In other words, the filling of the second via holes102with the second conductive paste141is performed in the state where the organic solvent included in the first conductive paste131is solidified. This can inhibit the second conductive paste141from entering the first via holes101.

Note that the state where the organic solvent included in the first conductive paste131is solidified is the state in which, in the step inFIG. 9Bdescribed above, the organic solvent which has not been adsorbed by the adsorption sheet160and has remained in the first via holes101is solidified.

Then, in another step other than each of the foregoing steps, as shown inFIGS. 9E and 9F, on each of the one surfaces110aand120aof the insulating layer110and the back-surface protection member120which face the insulating base material100, a copper foil or the like is formed. Then, by appropriately patterning the copper foil, the insulating layer110formed with the plurality of top-surface patterns111spaced apart from each other and the back-surface protection member120formed with the plurality of back-surface patterns121spaced apart from each other are prepared. As also shown inFIG. 7, the surface protection member115formed with the plurality of wiring patterns116is prepared.

Then, as shown inFIG. 9(g), the back-surface protection member120, the insulating base material100, the insulating layer110, and the surface protection member115are successively stacked to form a stacked body170.

Subsequently, as shown inFIG. 9H, the stacked body170is disposed between a pair of pressing plates not shown. Then, a pressure is applied thereto, while the stacked body170is heated from the both upper and lower surfaces in the stacking direction thereof in a vacuum state, thus forming the integrated stacked body170. Specifically, the first and second conductive pastes131and141are subjected to solid-phase sintering to form the first and second interlayer connection members130and140and the pressure is applied to the laminated body170, while the laminated body170is heated such that the first and second interlayer connection members130and140are connected to the top-surface patterns111and the back-surface patterns121, thus forming the integrated stacked body170.

Note that, when the integrated stacked body170is formed, a shock-absorbing material such as Rockwell paper may also be placed between the stacked body170and the pressing plates, though the formation of the stacked body170is not particularly limited. In this manner, the foregoing sensor module2is manufactured.

Next, a description will be given of a method of measuring a heat flow distribution using the heat flow distribution measurement device1in the present embodiment.

As shown inFIGS. 2 and 3, the measurement target31is placed on the stage23so as to face the one surface2aof the sensor module2. By adjusting the height of the sensor head21, the sensor module2is brought into a state in contact or non-contact with the measurement target31.

Then, a heat flow from the measurement target31or a heat flow toward the measurement target31passes through the sensor module2in a direction perpendicular to the one surface2aand the other surface2bof the sensor module2. As a result, the electromotive force is output from each of the heat flow sensor portions10to the electronic control unit3.

The electronic control unit3arithmetically determines a heat flow distribution on the basis of the electromotive force from each of the heat flow sensor portions10to thus allow the heat flow distribution of the measurement target31to be obtained. The electronic control unit3also performs image processing and causes the display unit4to display a two-dimensional image of the heat flow distribution to thus allow the heat flow distribution of the measurement target31to be recognized as the two-dimensional image. For example, as shown inFIG. 10, a heat flow distribution image4ashowing the magnitude of the heat flow from the region corresponding to the measurement target31is displayed on the display unit4. Note that, in the present embodiment, each one of the heat flow sensor portions10corresponds to one pixel (one of the quadrilaterals inFIG. 10) as a minimum unit of the heat flow distribution image4a.

As has been described heretofore, the heat flow distribution measurement device1in the present embodiment uses the sensor module2having the plurality of heat flow sensor portions10formed in the single multilayer substrate. The thermoelectric conversion elements included in each of the heat flow sensor portions10, i.e., the first and second interlayer connection members130and140are formed in the single multilayer substrate and are therefore manufactured by the same manufacturing process for manufacturing the multilayer substrate. Accordingly, the performance differences between the individual thermoelectric conversion elements can be reduced to be smaller than in the case where the plurality of heat flow sensors are manufactured as separate and independent bodies.

Thus, the heat flow distribution measurement device1in the present embodiment allows the heat flow distribution to be measured with higher precision than in the case where a heat flow distribution is measured using a plurality of heat flow sensors manufactured as separate and independent bodies.

The heat flow distribution measurement device1in the present embodiment allows the heat flow distribution to be measured in a state where the sensor module2is in contact or non-contact with the measurement target31.

In the case of performing the measurement in a state where a plurality of heat flow sensors manufactured as separate and independent bodies are in contact with the measurement target31, it is necessary to uniformize the states of contact of the plurality of heat flow sensors. However, when each of the plurality of heat flow sensors is manually attached to the measurement target, the state of contact varies so that it is difficult to uniformize the states of contact of the plurality of heat flow sensors.

By contrast, in the case of performing the measurement in the state where the sensor module2is in contact with the measurement target31in the present embodiment, the one sensor module2is brought into contact with the measurement target31. This allows the states of contact of the individual heat flow sensor portions10to be uniformized.

Note that, in the present embodiment, the heat flow passing through one of the heat flow sensor portions10is determined and the distribution of the heat flow through the heat flow sensor portion10per unit area is measured as the heat flow distribution. However, as the heat flow distribution, the distribution of a heat flow flux through each one of the heat flow sensor units10may also be measured. Note that a heat flow is the amount of heat energy flowing per unit time and W is used as the unit thereof, while a heat flow flux is the amount of heat traversing a unit area in a unit time and W/m2is used as the unit thereof.

Second Embodiment

As shown inFIG. 11, in the heat flow distribution measurement device1of the present embodiment, the plurality of heat flow sensor portions10are arranged in one row in one direction D1and a sensor module200having a shape elongated in the one direction D1is used. The sensor module200is obtained by changing the number of the plurality of heat flow sensor portions10in the sensor module2of the first embodiment. The internal structure and the manufacturing method of the sensor module200are the same as those of the first embodiment. Each of the heat flow sensor portions10in the sensor module200is connected to the electronic control unit3via wiring in the same manner as in the first embodiment.

As shown inFIGS. 12 and 13, the heat flow distribution measurement device1of the present embodiment includes the sensor head21, a uniaxial direction movement unit24, and the stage23.

The sensor head21of the present embodiment has a shape elongated in the one direction D1. The sensor module200is placed on the lower surface of the sensor head21with the longitudinal direction of the sensor head21coinciding with the longitudinal direction D1of the sensor module2. Consequently, another surface200bof the sensor module200is fixed to the sensor head21, while one surface200aof the sensor module200faces the measurement target31.

The uniaxial direction movement unit24is a movement unit which moves the sensor head21in a uniaxial direction. A movement direction D2of the sensor head21is perpendicular to the longitudinal direction D1of the sensor module2. As the uniaxial direction movement unit24, a movement unit having a known mechanism can be used. The movement of the uniaxial direction movement unit24is controlled by the electronic control unit3. The electronic control unit3is adapted to be able to acquire the positional information of the sensor head21. For example, to the uniaxial direction movement unit24, a sensor for acquiring the positional information of the sensor head21, which is not shown, is attached. On the basis of a sensor signal from this sensor, the electronic control unit3acquires the positional information of the sensor head21.

Next, a description will be given of a method of measuring a heat flow distribution using the heat flow distribution measurement device1of the present embodiment.

As shown inFIGS. 12 and 13, the measurement target31is placed on the stage23so as to face the one surface200aof the sensor module200. By adjusting the height of the sensor head21, the sensor module200is brought into a state in non-contact with the measurement target31.

When the heat flow distribution is measured, the sensor head21is moved. Accordingly, the sensor module200moves over the surface of the measurement target31. At this time, a heat flow from the measurement target31or a heat flow toward the measurement target31passes through the sensor module200in a direction perpendicular to the one surface200aand the other surface200bof the sensor module200. As a result, the electromotive force generated in each of the plurality of heat flow sensor portions10is output to the electronic control unit3.

Then, the electronic control unit3arithmetically determines a heat flow distribution on the basis of the electromotive force in each of the heat flow sensor portions10and the positional information of the sensor head21when the electromotive force is output. Thus, in the same manner as in the first embodiment, the heat flow distribution of the measurement target31is obtained.

Third Embodiment

In the second embodiment, the sensor module200in which the plurality of heat flow sensor portions10are arranged in one row is used. By contrast, in the present embodiment, as shown inFIG. 14, a sensor module201in which the plurality of heat flow sensor portions10are arranged in two rows is used.

Also, in the sensor module201, the respective positions of the heat flow sensor portions10in the adjacent rows which face each other are shifted from each other by a predetermined distance in the one direction D1in which the plurality of heat flow sensor portions10in one row are arranged. In the present embodiment, the predetermined distance is set to a length L1corresponding to ½ of the width of each one of the heat flow sensor portions10.

In the present embodiment also, in the same manner as in the second embodiment, the heat flow distribution is measured while the sensor head21is moved in a direction perpendicular to the one direction D1.

By thus using the sensor module201in which the adjacent rows are placed to be shifted from each other by the predetermined distance, in the same manner as when the width of each one of the heat flow sensor portions10is set to the predetermined distance L1, the heat flow distribution can be measured. Thus, according to the present embodiment, the resolution of the heat flow distribution measurement can be increased without reducing the area of each one of the heat flow sensor portions10. That is, each one of the pixels in the heat flow distribution image4adisplayed on the display unit4can be reduced in size.

Fourth Embodiment

As shown inFIG. 15, the present embodiment uses a sensor module202in which the plurality of heat flow sensor portions10are arranged in three rows. In the sensor module202also, in the same manner as in the second embodiment, the adjacent rows are placed to be shifted from each other by a predetermined distance. In the present embodiment, the predetermined distance is set to a length L2corresponding to ⅓ of the width of each one of the heat flow sensor portions10. By thus increasing the number of the rows and reducing the predetermined distance, the resolution can further be increased.

Fifth Embodiment

As shown inFIG. 16, the present embodiment is achieved by adding a heat medium flow path25to the heat flow distribution measurement device1inFIG. 3described in the first embodiment.

In the present embodiment, the heat medium flow path25is provided in the sensor head21. In the heat medium flow path25, a cooling heat medium26which cools the sensor module2flows. As the cooling heat medium, a typical cooling liquid such as an antifreeze liquid can be used. In the present embodiment, the heat medium flow path25is connected to a heat sink, a pump, or the like not shown. Thus, a cooling liquid circulation circuit in which a cooling liquid at a predetermined temperature circulates is configured.

Differently from the present embodiment, in the case where the heat medium flow path25is not provided in the sensor head21, when the heat flow distribution of the heat flow released from the measurement target31as a heat generator is measured, the sensor module2is heated by the measurement target31and the temperature of the sensor module2is increased. As a result, as time elapses, the heat flow passing through each of the heat flow sensor portions10changes so that the heat flow measurement value of each of the heat flow sensor portions10changes. That is, the heat flow measurement value of each of the heat flow sensor portions10drifts.

However, in the present embodiment, the heat medium flow path25in which the cooling heat medium26for cooling the sensor module2flows is provided in the sensor head21, i.e., in the other surface2bof the sensor module2. Accordingly, by allowing the cooling liquid to flow in the heat medium flow path25when the heat flow distribution of the heat flow released from the measurement target31as the heat generator is measured, the other surface2bof the sensor module2can be cooled with the cooling liquid.

As a result, even when the sensor module2is heated by the measurement target31, the temperature of the sensor module2can be held substantially constant and the heat flow passing through each of the heat flow sensor portions10can be stabilized. This can inhibit the heat flow measurement value of each of the heat flow sensor portions10from drifting.

Note that, in the present embodiment, it is preferable that the temperature of the sensor module2is measured using a temperature sensor not shown and, on the basis of the measured temperature of the sensor module2, the electronic control unit3controls the flow rate of the cooling heat medium26flowing in the heat medium flow path25such that the temperature of the sensor module2is adjusted to be held constant.

In the present embodiment, the heat medium flow path25in which the cooling heat medium26flows is provided in the sensor head21. However, instead of the heat medium flow path25, another cooler such as a heat sink or a heat pipe may also be provided.

Also, in the present embodiment, the case where the measurement target31is the heat generator has been described. However, in the case where the measurement target31is a heat absorber, a heating heat medium for heating the measurement target31is used instead of the cooling heat medium26. As a result, even when the sensor module2is cooled by the measurement target31in the same manner as in the present embodiment, the temperature of the sensor module2can be held substantially constant and the heat flow passing through each of the heat flow sensor portions10can be stabilized. This can inhibit the heat flow measurement value of each of the heat flow sensor portions10from drifting. Note that, in this case also, a heater such as an electric heater may also be provided instead of the heat medium flow path25in which the heating heat medium flows.

Sixth Embodiment

As shown inFIG. 17, the present embodiment has been achieved by replacing the stage23in the heat flow distribution measurement device1inFIG. 16described in the fifth embodiment with a heater27.

In the present embodiment, on the surface of the measurement target31which is opposite to the surface thereof closer to the sensor module2, the heater27is disposed. The heater27is for heating the measurement target31and is formed of an electric heater or the like.

In the measurement of the heat flow distribution using the heat flow distribution measurement device1, the measurement is performed in the same manner as in the fifth embodiment in the state in which the measurement target31is heated using the heater27.

According to the present embodiment, the heat flow distribution of the heat flow released from the heater27and passing through the measurement target31can be measured. Consequently, it is possible to precisely measure the distribution of the heat insulating property of the measurement target31and evaluate the heat insulating performance of the measurement target31.

Other Embodiments

The present disclosure is not limited to the embodiment described above, but can be changed appropriately as follows.

(1) In each of the embodiments described above, the heat flow is calculated on the basis of the electromotive force (voltage value) generated in each of the heat flow sensor portions. However, the calculation may also be performed on the basis of a current value instead of the voltage value. Briefly, the heat flow can be calculated on the basis of an electric output such as the voltage or current generated in the heat flow sensor portion.

(2) In each of the embodiments described above, the respective metals forming the first and second interlayer connection members130and140are the Bi—Sb—Te alloy and the Bi—Te alloy. However, the metal forming each of the first and second interlayer connection members130and140may also be another alloy. In each of the embodiments described above, each of the metals forming the first and second interlayer connection members130and140is a sintered alloy resulting from solid-phase sintering. However, it is appropriate that at least one of the metals forming the first and second interlayer connection members130and140is a sintered alloy resulting from solid-phase sintering. As a result, the electromotive force can be set larger than in the case where neither of the metals forming the first and second interlayer connection members130and140is a sintered metal resulting from solid-phase sintering.

(3) In each of the embodiments described above, the multilayer substrate included in the sensor module includes the plurality of stacked insulating layers each formed of a thermoplastic resin. However, the multilayer substrate may also include a plurality of stacked insulating layers each made of a material other than a thermoplastic resin. Examples of the material of the insulating layers which is other than a thermoplastic resin include a thermosetting resin.

(4) In each of the embodiments described above, the multilayer substrate has the configuration in which the insulating base material100, the insulating layer110, the top-surface protection member115, and the back-surface protection member120are stacked. However, the multilayer substrate may also have another configuration as long as a plurality of insulating layers are stacked therein. That is, the multilayer substrate may appropriately have the insulating base material100formed with the plurality of through holes101and102as one of the plurality of insulating layers. The number of the insulating layers located on both sides of the insulating base material100can arbitrarily be changed.

(5) In the first embodiment, it has been described that the electromotive force is output from each of the heat flow sensor portions10as a result of the passing of the heat flow through the sensor module2in a direction perpendicular to the one surface2aand the other surface2bof the sensor module2. However, the outputting of the electromotive force from each of the heat flow sensor portions10is not limited to the case where the heat flow passes through the sensor module2in a direction perpendicular to the one surface2aand the other surface2bof the sensor module2. In the case where the heat flow passes through the sensor module2in a direction extending from one of the one surface2aand the other surface2bof the sensor module2to the other thereof, an electromotive force is output from each of the heat flow sensor portions10. The same holds true in each of the embodiments described above which are other than the first embodiment. For example, in the second embodiment also, in the case where the heat flow passes through the sensor module200in a direction extending from one of the one surface200aand the other surface200bof the sensor module200to the other thereof, an electromotive force is output from each of the heat flow sensor portions10.

(6) In the sensor module2in the first embodiment, the plurality of heat flow sensor portions10are arranged in a matrix configuration in the directions parallel with the one surface2a. However, the directions in which the plurality of heat flow sensor portions10are arranged may also be directions oblique to the one surface2a, not directions completely parallel with the one surface2a. Briefly, the plurality of heat flow sensor portions10may appropriately be arranged in directions along the one surface2a. Note that the directions along the one surface2ainclude a direction completely parallel with the one surface2aand a direction approximately parallel with the one surface2a. The same also holds true in the sensor modules200,201,202, and the like in the second to fourth embodiments.

(7) In the second to fourth embodiments, the moving direction of the uniaxial direction movement unit24is perpendicular to the one direction D1in which the plurality of heat flow sensor portions10are arranged. However, the moving direction of the uniaxial direction movement unit24need not be perpendicular to the one direction D1. The moving direction of the uniaxial direction movement unit24may appropriately be a direction intersecting the one direction D1.

(8) The individual embodiments described above are by no means irrelevant to each other and can appropriately be combined unless a combination thereof is obviously unacceptable. Also, it goes without saying that, in each of the embodiments described above, the components thereof are not necessarily indispensable unless it is particularly clearly stated that the components of the embodiment are indispensable or unless the components of the embodiment can be considered to be obviously indispensable in principle.

It is understood that the present disclosure has been described in accordance with the embodiments, but the present disclosure is not limited to the embodiments and the structures thereof. The present disclosure also encompasses variations in the equivalent range as various modifications. In addition, various combinations and embodiments, and further, only one element thereof, less or more, and the form and other combinations including, are intended to fall within the spirit and scope of the present disclosure.