Thermal resistance measuring device, thermal resistance measuring method, and thermal resistance measuring program

Abstract

To enable the heat resistance of a measurement object to be measured with greater accuracy.SOLUTION: The present invention comprises: a temperature information input unit 31 for inputting measured temperatures having been measured by a plurality of temperature sensors attached to a test head; and a heat resistance specification unit 32 for calculating respectively the temperatures corresponding to the positions where the plurality of temperature sensors are attached by a calculation formula that, while giving the heat resistance and applied amount of heat of a measurement object as variables, includes the variables and the value representing the magnitude of heat leakage from the test head to the air, as terms, and outputting the values of the variables given when the calculated temperatures and the measured temperatures satisfy a prescribed matching condition, as a solution to the heat resistance of the measurement object. The heat resistance of the measurement object is calculated by an optimization calculation using the value of heat leakage from the test head to the air that varies by being affected by a heat flow in the surroundings of the measurement object, and the heat resistance can thereby be measured with greater accuracy in consideration of the influence of the surroundings.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a thermal resistance measuring device, a thermal resistance measuring method, and a thermal resistance measuring program, and more particularly to a technique for applying a heat flow to an object to be measured and measuring the thermal resistance of the object to be measured. [Background technology]

[0002] Conventionally, there is known a technique for measuring the thermal properties of a sample by sandwiching the sample between two rods equipped with thermocouples and measuring the temperature difference that occurs in the sample (see, for example, Patent Documents 1 and 2). In the thermal conductivity measuring device described in Patent Document 1, the object to be measured is sandwiched between a heating-side rod and a cooling-side rod, and heat is allowed to flow in and out through the heating-side rod, the object to be measured, and the cooling-side rod, thereby measuring the contact thermal resistance between both rods and the object to be measured.

[0003] In the thermal conductivity measuring device described in Patent Document 2, a measurement object is sandwiched between a heating-side clamping member (upper rod and upper sample block) and a cooling-side clamping member (lower rod and lower sample block), and heat flows from the heating-side clamping member to the cooling-side clamping member. In this state, the temperature difference between the upper and lower sample blocks is measured, as well as the temperature gradient in the upper rod and the temperature gradient in the lower rod, and the thermal conductivity of the measurement object is derived based on these measurement results and the thickness of the measurement object. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2006-145446 [Patent Document 2] Japanese Patent Application Laid-Open No. 2012-32196 Summary of the Invention [Problem to be solved by the invention]

[0005] As in Patent Documents 1 and 2, conventional techniques that sandwich a sample between heating and cooling rods from above and below and measure the thermal characteristics of the sample from the temperature difference between the rods assume that the temperature difference between the rods is entirely due to the thermal resistance of the sample. However, in reality, the temperature difference between the rods varies not only due to the thermal resistance of the rods but also due to the surrounding influence of heat leakage into the air. In particular, the magnitude of heat leakage into the air varies depending on the shape of the sample being measured. For this reason, the above conventional techniques have the problem of being unable to accurately measure the thermal resistance of the sample while taking into account the influence of surrounding heat flow. Furthermore, the conventional techniques can only measure samples that can be sandwiched between the rods, and therefore cannot measure the thermal resistance of actual products such as circuit boards.

[0006] The present invention has been made to solve such problems, and aims to construct a measurement system that takes into account the influence of heat flow around the object to be measured, thereby enabling more accurate measurement of the thermal resistance of the object to be measured. [Means for solving the problem]

[0007] In order to solve the above-mentioned problems, the thermal resistance measuring device of the present invention includes a test head including a contact portion that contacts a heater portion and an object to be measured, a plurality of temperature sensors attached at predetermined positions between the heater portion and the contact portion of the test head, and a computing device that calculates the thermal resistance of the object to be measured using temperature information measured by the plurality of temperature sensors for the test head. The computing device inputs temperature information of the actual temperatures measured for the test head by the plurality of temperature sensors, and calculates temperatures corresponding to the positions where the plurality of temperature sensors are attached using a predetermined formula that includes, as variables, the thermal resistance of the object to be measured and the amount of heat input from the heater portion and a value representing the magnitude of heat leakage from the test head to the air, and outputs the value of the given variable as a solution for the thermal resistance of the object to be measured when the calculated temperature and the actual measured temperature satisfy a predetermined consistency condition. [Effects of the Invention]

[0008] According to the present invention configured as described above, the thermal resistance of the measurement object is determined by a calculation using a predetermined formula that includes as terms the thermal resistance of the measurement object and a value representing the magnitude of heat leakage from the test head to the air. The value representing the magnitude of heat leakage from the test head to the air is a value that fluctuates due to the influence of heat flow around the measurement object. Therefore, according to the present invention, the influence of heat flow around the measurement object can be taken into account, making it possible to more accurately measure the thermal resistance of the measurement object. [Brief explanation of the drawings]

[0009] [Figure 1] 1 is a diagram showing an example of the overall configuration of a thermal resistance measuring device according to an embodiment of the present invention; [Figure 2] FIG. 2 is a block diagram illustrating an example of the functional configuration of a calculation device according to the present embodiment. [Figure 3] FIG. 1 shows an equivalent thermal network including a test head and a measurement object. [Figure 4] 4 is a flowchart showing an example of operation of the thermal resistance measuring device according to the present embodiment (a processing procedure of a thermal resistance measuring method). DETAILED DESCRIPTION OF THE INVENTION

[0010] An embodiment of the present invention will be described below with reference to the drawings. Fig. 1 is a diagram showing an example of the overall configuration of a thermal resistance measuring device according to this embodiment. As shown in Fig. 1, the thermal resistance measuring device 1 of this embodiment includes a test head 10, a plurality of temperature sensors 20, -1 ~20 -4 (Hereinafter, when no distinction is made between the temperature sensors, they may be simply referred to as temperature sensors 20) and a computing device 30. Note that Fig. 1 shows the test head 10, temperature sensors 20, computing device 30, and measurement object 100 in a schematic manner, and does not reproduce the actual shapes and connection states of each.

[0011] The test head 10 has a heater unit 11 that performs heating, a contact unit 12 that comes into contact with the measurement object 100, and a heat conduction unit 13 between the heater unit 11 and the contact unit 12. The contact unit 12 and the measurement object 100 are in contact with each other with a heat dissipation grease (not shown) interposed therebetween. The heater unit 11 applies a heat flow to the measurement object 100 that is in contact with the contact unit 12 via the heat conduction unit 13. This heats the measurement object 100, and the temperature rises according to its thermal resistance Rth_s.

[0012] Multiple temperature sensors 20 -1 ~20 -4 are attached to predetermined positions in the heat conducting section 13 between the heater section 11 and the contact section 12 of the test head 10, and measure the temperatures T1 to T4 at each position. The temperature sensors 20 can be configured by sensors using thermocouples, for example. -1 ~20 -4 The position where the temperature sensors 20 are attached may be any position on the heat conducting portion 13, and there are no special installation conditions. -1 ~20 -4 may be provided at equal intervals.

[0013] The temperature of the heat conductive portion 13 rises due to heating by the heater portion 11, but this temperature rise is affected by the thermal resistance Rth_s of the measurement object 100. That is, if the thermal resistance Rth_s of the measurement object 100 is large, the temperature rise of the heat conductive portion 13 will be relatively high, and if the thermal resistance Rth_s is small, the temperature rise of the heat conductive portion 13 will be relatively low. As a result, the temperatures T1 to T4 of the test head 10 measured by the temperature sensor 20 will be values ​​that correspond to the thermal resistance Rth_s of the measurement object 100 that is in contact with the test head 10.

[0014] The temperature rise of the heat conductive part 13 is also affected by the amount of heat leakage from the measurement object 100 to the air. That is, when there is a lot of heat leakage from the measurement object 100 to the air, the temperature rise of the heat conductive part 13 will be relatively low, and when there is little heat leakage from the measurement object 100 to the air, the temperature rise of the heat conductive part 13 will be relatively high. As a result, the temperatures T1 to T4 of the test head 10 measured by the temperature sensor 20 will be values ​​that correspond to the amount of heat leakage from the measurement object 100 in contact with the test head 10 to the air.

[0015] Furthermore, the heat conducting portion 13 also has a thermal resistance, and the temperatures T1 to T4 measured at each position by the temperature sensor 20 are also affected by the thermal resistance of the heat conducting portion 13. As shown in FIG. -1 and the second temperature sensor 20 -2 The thermal resistance between 12 and the second temperature sensor 20 -2 and a third temperature sensor 20 -3 The thermal resistance between 23 and the third temperature sensor 20 -3 and a fourth temperature sensor 20 -4 The thermal resistance between 34 and the fourth temperature sensor 20 -4 The thermal resistance between the object 100 and the object to be measured is r 4t The temperatures at each position T1 to T4 are expressed as the thermal resistance r 12 ,r 23 ,r 34 ,r 4t The value depends on the

[0016] The arithmetic device 30 calculates the thermal resistance Rth_s of the measurement object 100 using temperatures T1 to T4 measured at each position on the test head 10 by the multiple temperature sensors 20. FIG. 2 is a block diagram showing an example of the functional configuration of the arithmetic device 30. As shown in FIG. 2, the arithmetic device 30 includes, as its functional configuration, a temperature information input unit 31 and a thermal resistance specifying unit 32. More specifically, the thermal resistance specifying unit 32 includes, as its functional configuration, a fixed value setting unit 32A, a variable setting unit 32B, a temperature calculation unit 32C, a matching condition determination unit 32D, and a thermal resistance output unit 32E.

[0017] The functional blocks 31 and 32 can be configured by any of hardware, a DSP (Digital Signal Processor), and software. For example, when configured by software, the functional blocks 31 and 32 are actually configured with a CPU, RAM, ROM, etc. of a computer, and are realized by running a thermal resistance measurement program stored in a storage medium such as RAM, ROM, a hard disk, or a semiconductor memory.

[0018] The temperature information input unit 31 inputs temperature information of actual temperatures T1 to T4 at each position of the heat conducting unit 13 measured by the multiple temperature sensors 20 for the test head 10. Here, the temperature information input unit 31 preferably inputs temperature information measured by the temperature sensors 20 when the temperature of the heat conducting unit 13 reaches a steady state a predetermined time after heating by the heater unit 11 is started. For example, the temperature information input unit 31 monitors the temperature information input from the temperature sensors 20 from the time heating by the heater unit 11 is started, and inputs the temperature when it is determined that there is almost no temperature change and the temperature has reached a steady state as the actual temperatures T1 to T4 at each position.

[0019] The thermal resistance specifying unit 32 calculates temperatures (hereinafter referred to as calculated temperatures t1 to t4) corresponding to the positions where the plurality of temperature sensors 20 are attached, using a predetermined calculation formula that includes, as terms, values ​​representing the variables Rth_s, Qin, and the magnitude of heat leakage Qloss from the test head 10 to the air, while giving the thermal resistance Rth_s of the measurement object 100 and the amount of heat input Qin from the heater unit 11 as variables. Then, when the calculated temperatures t1 to t4 and the measured temperatures T1 to T4 satisfy predetermined matching conditions, the value of Rth_s given as a variable is output as a solution for the thermal resistance Rth_s of the measurement object 100.

[0020] The following describes a specific functional configuration of the thermal resistance specifying unit 32. The fixed value setting unit 32A determines the thermal resistance r 12 ,r 23 ,r 34 ,r4t , the heat leakage Qloss from the test head 10 to the air, and the external temperature Ta of the measurement object 100 are set. FIG. 3 is a diagram showing an equivalent thermal circuit network including the test head 10 and the measurement object 100. In FIG. 3, fixed values ​​set by the fixed value setting unit 32A are shown. For the heat leakage Qloss to the air, the multiple temperature sensors 20 -1 ~20 -4 and the fourth temperature sensor 20 -4 and the contact portion 12, respectively, and the respective heat leaks Qloss are assumed to be Q 12 loss,Q 23 loss,Q 34 loss,Q 4t It is expressed as loss.

[0021] The external temperature Ta is a value measured by a temperature sensor (not shown) and is manually set by the user. 12 ,r 23 ,r 34 ,r 4t For example, the user manually sets the overall thermal resistance of the heat conducting portion 13 measured in advance for the test head 10, and the fixed value setting unit 32A automatically sets a value that is logically calculated from this overall thermal resistance. -1 ~20 -4 and the distance between the fourth temperature sensor 20 -4 The thermal resistance r is the value obtained by dividing the entire thermal resistance of the heat conducting portion 13 in proportion to the distance between the heat conducting portion 13 and the contact portion 12. 12 ,r 23 ,r 34 ,r 4t It is possible to set it to

[0022] Heat loss to air Qloss(Q 12 loss,Q 23 loss,Q 34 loss,Q 4tFor example, the fixed value setting unit 32A automatically sets a value calculated by the logical formula shown in the following (Formula 1) for heat leakage Qloss. Here, as shown in (Formula 1), the fixed value setting unit 32A uses the measured temperatures T1 to T4 input by the temperature information input unit 31 when calculating the heat leakage Qloss. On the other hand, (Formula 1) is an equation that does not include thermal resistance Rth_s as a parameter, and it is possible to logically calculate the heat leakage Qloss even if the thermal resistance Rth_s is unknown. Note that the logical formula shown here is an example and is not limited to this.

[0023]

number

[0024] As described above, the actual temperatures T1 to T4 measured by the temperature sensor 20 are affected by the thermal resistance Rth_s of the measurement object 100 in contact with the test head 10 and the heat leakage from the measurement object 100 to the air, and are values ​​that fluctuate in response to these effects. The heat leakage Qloss from the test head 10 to the air is calculated using Equation 1, which uses the actual temperatures T1 to T4 as parameters, and is therefore a value that depends on the thermal resistance Rth_s of the measurement object 100 and the heat leakage from the measurement object 100. In other words, the heat leakage Qloss from the test head 10 can be said to be a value that fluctuates in response to the influence of the heat flow around the measurement object 100.

[0025] The variable setting unit 32B sets the thermal resistance Rth_s of the measurement object 100 and the amount of heat input Qin from the heater unit 11 as variables. The variable setting unit 32B may automatically set random values ​​as these variables Rth_s and Qin, but it is preferable to set them to values ​​limited to a predetermined range. This is because setting a certain limit on the combination of the variables Rth_s and Qin to be set can shorten the calculation time until a solution is found. Note that the predetermined range that can be set as a variable may be changed depending on the measurement object 100.

[0026] The temperature calculation unit 32C calculates the temperature by the fixed value set by the fixed value setting unit 32A (the thermal resistance r 12 ,r 23 ,r 34 ,r 4t , heat leakage Q from the test head 10 to the air 12 loss,Q 23 loss,Q 34 loss,Q 4t Using the variables set by the variable setting unit 32B (thermal resistance Rth_s of the object to be measured 100 and the amount of heat input Qin from the heater unit 11), the following formula (Equation 2) derived from the thermal circuit network shown in Figure 3 is used to calculate calculated temperatures t1 to t4 corresponding to the positions where the multiple temperature sensors 20 are attached.

[0027]

number

[0028] The matching condition determination unit 32D determines whether the calculated temperatures t1 to t4 calculated by the temperature calculation unit 32C and the measured temperatures T1 to T4 input by the temperature information input unit 31 satisfy a predetermined matching condition. If it is determined that the matching condition is not satisfied, the values ​​of the variables Rth_s and Qin set by the variable setting unit 32B are changed, and the processing of the temperature calculation unit 32C and the matching condition determination unit 32D is executed again. The thermal resistance output unit 32E outputs the value of Rth_s that was set as a variable when it was determined by the matching condition determination unit 32D that the matching condition is satisfied as a solution for the thermal resistance Rth_s of the measurement object 100.

[0029] The matching condition used by the matching condition determination unit 32D is a condition that the difference between the calculated temperatures t1 to t4 and the measured temperatures T1 to T4 is minimized, and for example, the matching condition can be that the index value α shown in the following (Equation 3) is minimized. α=(T1-t1) 2 +(T2-t2) 2 +(T3-t3) 2 +(T4-t4) 2 ...(Formula 3) The determination of whether the index value α has been minimized can be made, for example, by determining whether the index value α has become equal to or less than a predetermined value. Alternatively, the determination may be made by determining whether the index value α has become a minimum value. Alternatively, the determination may be made by determining whether the index value α has become equal to or less than the predetermined value a predetermined number of times or more.

[0030] FIG. 4 is a flowchart showing an example of the operation of the thermal resistance measuring device 1 according to this embodiment configured as above (the processing procedure of the thermal resistance measuring method).

[0031] First, the heater unit 11 of the test head 10 heats the measurement object 100 in contact with the contact unit 12 of the test head 10 (step S1). Then, the temperature information input unit 31 of the computing device 30 inputs temperature information of the actual temperatures T1 to T4 measured at each position on the test head 10 by the multiple temperature sensors 20 (step S2).

[0032] Next, the fixed value setting unit 32A of the arithmetic device 30 sets the fixed value (thermal resistance r 12 ,r 23 ,r 34 ,r 4t , heat leakage Q from the test head 10 to the air 12 loss,Q 23 loss,Q 34 loss,Q 4t loss, and the external temperature Ta of the measurement object 100 (step S3). The variable setting unit 32B also sets variables (thermal resistance Rth_s of the measurement object 100 and the input heat amount Qin from the heater unit 11) used in the calculation formula (Equation 2) (step S4).

[0033] Next, the temperature calculation unit 32C calculates calculated temperatures t1 to t4 corresponding to the positions where the plurality of temperature sensors 20 are attached, using the calculation formula shown in (Equation 2) (step S5). Then, the matching condition determination unit 32D determines whether the calculated temperatures t1 to t4 calculated by the temperature calculation unit 32C and the measured temperatures T1 to T4 input by the temperature information input unit 31 satisfy a predetermined matching condition (step S6).

[0034] Here, if the matching condition determination unit 32D determines that the predetermined matching condition is not satisfied, the process returns to step S4. Then, the values ​​of the variables Rth_s and Qin set by the variable setting unit 32B are changed, and the processes of steps S5 and S6 are executed again. If the matching condition determination unit 32D determines in step S6 that the predetermined matching condition is satisfied, the thermal resistance output unit 32E outputs the value of Rth_s that was set as the variable in step S4 when it was determined that the matching condition is satisfied as the solution for the thermal resistance Rth_s of the measurement object 100 (step S7). This ends the process of the flowchart shown in FIG.

[0035] As described above in detail, in this embodiment, the thermal resistance Rth_s of the measurement object 100 and the input heat quantity Qin from the heater unit 11 are given as variables, and the calculated temperatures t1 to t4 corresponding to the positions where the multiple temperature sensors 20 are attached are calculated using the calculation formula (Equation 2) including the variables Rth_s, Qin, and the heat leakage Qloss from the test head 10 to the air. The value of the variable Rth_s given when the calculated calculated temperatures t1 to t4 and the actual measured temperatures T1 to T4 by the multiple temperature sensors 20 satisfy a predetermined matching condition is output as a solution for the thermal resistance Rth_s of the measurement object 100. According to this embodiment configured in this manner, the thermal resistance Rth_s of the measurement object 100 can be measured more accurately by taking into account the influence of heat flow around the measurement object 100 through the heat leakage Qloss. This makes it possible to measure the thermal resistance Rth_s of the measurement object 100 when it is in contact with the tip of the test head 10. In other words, the lower rod used in the prior art can be eliminated from the measurement system, making it possible to measure samples other than those that fit the rod shape.

[0036] In the above embodiment, four temperature sensors 20 -1 ~20 -4 Although an example in which temperatures T1 to T4 are measured at four locations has been described, this number is merely an example.

[0037] In the above embodiment, the processes of the variable setting unit 32B, the temperature calculation unit 32C, and the matching condition determination unit 32D are repeated until a predetermined matching condition is satisfied. However, the present invention is not limited to this. For example, all possible combinations of the thermal resistance Rth_s and the input heat amount Qin may be set using values ​​within a predetermined range, the index value α may be calculated for all combinations, and the combination with the smallest index value α may be used as the matching condition.

[0038] Furthermore, the above-described embodiments are merely examples of specific embodiments for carrying out the present invention, and the technical scope of the present invention should not be construed as being limited thereby. In other words, the present invention can be carried out in various forms without departing from the gist or main characteristics thereof. [Explanation of symbols]

[0039] 1. Thermal resistance measuring device 10 Test Head 11 Heater section 12 Contact part 13 Heat conduction section 20 -1 ~20 -4 Temperature Sensor 30 Arithmetic unit 31 Temperature information input section 32 Thermal resistance specific part 32A Fixed value setting section 32B Variable setting section 32C temperature calculation section 32D Matching condition judgment section 32E Thermal resistance output section

Claims

1. a test head including a heater unit for heating and a contact unit with which the measurement object comes into contact; a plurality of temperature sensors attached at predetermined positions between the heater portion and the contact portion of the test head; a calculation device that calculates the thermal resistance of the measurement object using temperature information measured by the plurality of temperature sensors for the test head, The computing device a temperature information input unit for inputting the temperature information of the actual temperatures measured by the plurality of temperature sensors for the test head; a thermal resistance specifying unit that calculates temperatures corresponding to the positions where the plurality of temperature sensors are attached using a predetermined calculation formula that includes, as terms, the thermal resistance of the object to be measured and the amount of heat input from the heater unit as variables, and that outputs the value of the variable given when the calculated temperature and the actually measured temperature satisfy a predetermined matching condition as a solution for the thermal resistance of the object to be measured. A thermal resistance measuring device characterized by:

2. 2. The thermal resistance measuring device according to claim 1, wherein the value representing the magnitude of heat leakage from the test head to the air is a value calculated using a predetermined formula that includes the measured temperature as a term.

3. a first step of heating a measurement object that is in contact with a contact portion of the test head by a heater portion of the test head; a second step in which a temperature information input unit of a computing device inputs temperature information of actual temperatures measured for the test head by a plurality of temperature sensors attached at predetermined positions between the heater unit and the contact unit of the test head; a third step in which the thermal resistance specifying unit of the computing device calculates temperatures corresponding to the positions where the plurality of temperature sensors are attached using a predetermined calculation formula including, as terms, the thermal resistance of the object to be measured and the amount of heat input from the heater unit as variables, and outputs the value of the variable given when the calculated temperature and the actually measured temperature satisfy a predetermined matching condition as a solution for the thermal resistance of the object to be measured. A thermal resistance measuring method comprising:

4. A thermal resistance measurement program that causes a computing device to execute a process of calculating the thermal resistance of a measurement object using temperature information measured by a plurality of temperature sensors for a test head when the measurement object is in contact with a contact portion of the test head and heated by a heater portion of the test head, a temperature information input means for inputting the temperature information of the actual temperatures measured for the test head by the plurality of temperature sensors attached at predetermined positions between the heater portion and the contact portion; and a thermal resistance specifying means for calculating the temperatures corresponding to the positions where the plurality of temperature sensors are attached using a predetermined calculation formula including, as terms, the thermal resistance of the object to be measured and the amount of heat input from the heater unit as variables, and outputting the value of the variable given when the calculated temperature and the actually measured temperature satisfy a predetermined matching condition as a solution for the thermal resistance of the object to be measured; A thermal resistance measurement program for causing the computer of the arithmetic unit to function as a thermal resistance measurement program.

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