Electrical Circuit Board

Abstract

The electric circuit board comprises an insulating substrate (1), conductor patterns (2), (3), (5) formed on a surface of the insulating substrate (1) and onto which a high-frequency signal is incident, and temperature measurement patterns (11)-(15), (21)-(24) formed on the surface of the insulating substrate (1) and having an infrared emissivity higher than that of the conductor patterns (2), (3), (5).

Description

[Technical field]

[0001] The present disclosure relates to an electric circuit board having a conductor pattern formed on a surface of a board. [Background technology]

[0002] Patent Document 1 discloses an invention that focuses on the fact that in a wiring board on which electronic components such as semiconductors are mounted, the electronic components become damaged or malfunction when they reach high temperatures. Patent Document 1 shows a wiring board that has a heat radiation layer that covers all or part of the surface on which a conductor pattern on which electronic components are mounted is formed, thereby improving the heat dissipation properties of the wiring board surface and suppressing the temperature rise of the electronic components. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2008-251950 A Summary of the Invention [Problem to be solved by the invention]

[0004] On the other hand, electric circuit boards are becoming increasingly dense and high output, and there is a demand to be able to measure the surface temperature of an insulating substrate or the temperature of a conductor pattern formed on the surface of an insulating substrate, particularly in electric circuit boards on which high-frequency circuits are mounted.

[0005] The present disclosure has been made in consideration of the above-mentioned points, and has an object to provide an electric circuit board that can measure the temperature of a conductor pattern formed on the surface of the board without contacting the conductor pattern. [Means for solving the problem]

[0006] The electric circuit board according to the present disclosure comprises an insulating substrate, a conductor pattern formed on a surface of the insulating substrate and onto which a high-frequency signal is incident, and a temperature measurement pattern formed on the surface of the insulating substrate and having an infrared emissivity higher than that of the conductor pattern. Effect of the Invention

[0007] According to the present disclosure, by using a temperature measurement pattern, the surface temperature of a conductor pattern located directly below the temperature measurement pattern or the surface temperature of an insulating substrate can be measured in a non-contact manner with high accuracy. [Brief description of the drawings]

[0008] [Figure 1] 1 is a plan view of a main portion of an electric circuit board according to a first embodiment. [Diagram 2] 2 is a cross-sectional view taken along line AA in FIG. 1. [Diagram 3] 11 is a plan view of a main portion of an electric circuit board according to a second embodiment. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] Embodiment 1 The electric circuit board according to the first embodiment will be described with reference to FIGS. The electric circuit board according to the first embodiment is an electric circuit board on which a high-frequency circuit is mounted, and in which conductor patterns 2 and 3 are formed on the surface of an insulating substrate 1. The electric circuit board according to the first embodiment includes an insulating substrate 1, a first conductor pattern 2, a second conductor pattern 3, a ground conductor 4, and a first pattern 11 to a fifth pattern 15 for temperature measurement.

[0010] A first conductor pattern 2 and a second conductor pattern 3 are formed on the front surface of an insulating substrate 1, and a ground conductor 4 is formed on the back surface of the insulating substrate 1. The first conductor pattern 2 and the second conductor pattern 3 are each a microstrip line configured between a ground conductor 4 . Each of the first conductor pattern 2 and the second conductor pattern 3 may form a coplanar line or a differential line.

[0011] The first conductor pattern 2 and the second conductor pattern 3 are metal wiring layers formed as fine circuit patterns by adhering or vapor-depositing copper or gold foil onto the surface of the insulating substrate 1 and etching or the like. The first conductor pattern 2 and the second conductor pattern 3 are each formed on the surface of the insulating substrate 1 with their metal surfaces exposed.

[0012] As shown in FIG. 1, the first conductor pattern 2 has a line 2a with a characteristic impedance of 50 Ω and a thin line portion 2b whose line width is narrower than that of the line 2a. The second conductor pattern 3 has a line 3a with a characteristic impedance of 50 Ω and a bent portion 3b formed by bending the line 3a, as shown in Fig. 1. The bent portion 3b shown in Fig. 1 is a 90-degree bend, but it may be a bent portion curved in an arc shape.

[0013] High frequency signals are transmitted to the first conductor pattern 2 and the second conductor pattern 3, respectively. When a high-frequency current caused by a high-frequency signal flows through each of the first conductor pattern 2 and the second conductor pattern 3, the first conductor pattern 2 and the second conductor pattern 3 generate heat due to conductor loss and dielectric loss, and the temperature rises. The conductor loss in each of the first conductor pattern 2 and the second conductor pattern 3 is due to the current amplitude due to the high-frequency signal, and the dielectric loss in each of the first conductor pattern 2 and the second conductor pattern 3 is due to the voltage amplitude (electric field amplitude) due to the high-frequency signal.

[0014] Therefore, in order to measure the surface temperature of each of the first conductor pattern 2 and the second conductor pattern 3, it is possible to use an infrared thermograph (infrared thermography camera) or an infrared radiation thermometer that can measure the temperature of each of the first conductor pattern 2 and the second conductor pattern 3 without contact. Measuring surface temperature using an infrared thermograph or an infrared radiation thermometer has the advantage that it has almost no effect on the object and can measure the temperature in real time, as the temperature is detected using infrared rays emitted from the object.

[0015] Since the first conductor pattern 2 and the second conductor pattern 3 are each made of metal such as copper or gold, the infrared emissivity of the metal is low, at 0.2 or less, and it is therefore not possible to accurately measure the surface temperatures of the first conductor pattern 2 and the second conductor pattern 3 using an infrared thermograph or an infrared radiation thermometer. In other words, it is not suitable for surface temperature measurement, which detects the surface temperatures of the first conductor pattern 2 and the second conductor pattern 3 using infrared rays radiated from the metal surfaces of the first conductor pattern 2 and the second conductor pattern 3.

[0016] Each of the first temperature-measuring pattern 11 to the fifth temperature-measuring pattern 15 is formed of a solder resist pattern made of an insulating material such as resin or ceramics. The first temperature measurement pattern 11 to the fifth temperature measurement pattern 15 can be formed by a general circuit formation process without using a special manufacturing process, and thus does not involve a significant increase in cost.

[0017] That is, each of the first temperature-measuring pattern 11 to the fifth temperature-measuring pattern 15 is a solder resist pattern in which a solder resist made of an insulating material, either resin or ceramic, is applied onto the surface of an insulating substrate 1 having a first conductor pattern 2 and a second conductor pattern 3 formed on its surface, and then finely formed by etching or the like.

[0018] Each of the first temperature-measuring pattern 11 to the fifth temperature-measuring pattern 15 may be formed as a solder resist pattern by a method such as screen printing. Resins and ceramics are generally known to have high infrared emissivity.

[0019] The first temperature-measuring pattern 11 to the fifth temperature-measuring pattern 15 are formed on the surface of the first conductor pattern 2, the surface of the second conductor pattern 3 and the surface of the insulating substrate 1 with the surface of the solder resist made of resin or ceramics exposed. The infrared emissivity of the resin or ceramic solder resist constituting each of the first temperature-measurement pattern 11 to the fifth temperature-measurement pattern 15 is sufficiently higher than the infrared emissivity of the metal constituting each of the first conductor pattern 2 and the second conductor pattern 3, and is 0.8 or more.

[0020] Therefore, by detecting the infrared rays emitted from the surface of the solder resist of each of the first temperature-measurement pattern 11 to the fifth temperature-measurement pattern 15 using an infrared thermograph or an infrared radiation thermometer to detect the temperature, the surface temperatures of the first conductor pattern 2, the second conductor pattern 3, and the insulating substrate 1 can be measured with high accuracy.

[0021] The first temperature-measuring pattern 11 is formed in a rectangular shape on the surface of the line 2a of the first conductor pattern 2, spaced apart from both sides of the line 2a. That is, the first temperature measurement pattern 11 is locally disposed on the inside of the surface of the line 2a so as to avoid the edge of the line 2a.

[0022] The length of the long side of the first temperature-measuring pattern 11 is equal to or longer than the wavelength of infrared light. When infrared thermography is used to detect infrared rays emitted from the surface of the first temperature-measurement pattern 11 to detect temperature, i.e., measure temperature, the length of the long side of the first temperature-measurement pattern 11 is greater than or equal to the minimum spatial resolution of the infrared thermography. In embodiment 1, the length of the long side of the first temperature measurement pattern 11 is several tens of μm or more, preferably several μm or more, and is optimally the same as the size of the minimum spatial resolution, i.e., the same length as the minimum spatial resolution. The thickness of the first temperature-measuring pattern 11 is several tens of μm or less, and preferably several μm or less.

[0023] Furthermore, when an infrared radiation thermometer is used to detect infrared rays emitted from the surface of the first temperature-measurement pattern 11 to detect temperature, i.e., measure temperature, the length of the long side of the first temperature-measurement pattern 11 is longer than the minimum spot diameter of the infrared radiation thermometer and is optimally the same as the size of the minimum spot diameter, i.e., the same length as the minimum spot diameter.

[0024] In FIG. 1, one first temperature measurement pattern 11 is shown, but if there are multiple locations on the line 2a where the temperature needs to be measured, multiple first temperature measurement patterns 11 are placed locally on the inside of the surface of the line 2a corresponding to each of the multiple locations. It is desirable that the first temperature-measuring pattern 11 is locally formed in a portion of the line 2a, which is the heat dissipation source, where the thermal resistance is large or where the loss density is large.

[0025] As described above, the first temperature-measuring pattern 11 is formed locally on the surface of the line 2a, and therefore does not increase electrical loss, thereby suppressing the effect on high-frequency loss. As a result, the surface temperature of the line 2a in the first conductor pattern 2 can be measured with high accuracy using an infrared thermograph or an infrared radiation thermometer while maintaining the high-frequency characteristics in the high-frequency circuit. Furthermore, when a high-frequency current flows through the first conductor pattern 2, the electric field strength becomes high along the sides, i.e., at the edges, of the line 2a. Therefore, the first temperature-measuring pattern 11 is formed to avoid the edges of the line 2a, and therefore there is no increase in electrical loss to the high-frequency circuit.

[0026] The second temperature-measuring pattern 12 is formed in a rectangular shape on the surface of the thin line portion 2b of the first conductor pattern 2, spaced apart from both sides of the thin line portion 2b. That is, the second temperature-measuring pattern 12 is locally disposed on the inside of the surface of the thin wire portion 2b so as to avoid the edge of the thin wire portion 2b.

[0027] The length of the long side of the second temperature measurement pattern 12, like the length of the long side of the first temperature measurement pattern 11, is longer than the wavelength of infrared light, longer than the minimum spatial resolution of infrared thermography, or longer than the minimum spot diameter of an infrared radiation thermometer, and is optimally the same as the size of the minimum spatial resolution or the minimum spot diameter. Similarly to the thickness of the first temperature-measuring pattern 11, the thickness of the second temperature-measuring pattern 12 is several tens of μm or less, preferably several μm or less.

[0028] In the first conductor pattern 2, the temperature of the thin line portion 2b, where the current density is high and the temperature rise is higher than that of the line 2a, can be measured with high accuracy by detecting infrared rays emitted from the surface of the second temperature measurement pattern 12 using an infrared thermograph or an infrared radiation thermometer.

[0029] At this time, since the second temperature-measuring pattern 12 is formed locally on the surface of the thin line portion 2b, it does not increase electrical loss, so that the effect on high-frequency loss can be suppressed and the high-frequency characteristics in the high-frequency circuit can be maintained. Furthermore, when a high-frequency current flows through the first conductor pattern 2, the electric field strength becomes high along the sides, i.e., at the edges, of the thin line portion 2b. Therefore, the second temperature-measuring pattern 12 is formed to avoid the edges of the thin line portion 2b, and therefore does not increase electrical loss to the high-frequency circuit.

[0030] The third temperature-measuring pattern 13 is formed on the surface of a bent portion 3b formed by bending the line 3a of the second conductor pattern 3, and is spaced apart along both sides of the bent portion 3b. In the first embodiment, the planar shape of the third temperature-measuring pattern 13 is an L-shape. The third temperature-measuring pattern 13 is locally disposed on the inside at the inner corner side of the surface of the bent portion 3b so as to avoid the edge of the bent portion 3b.

[0031] The length of the long side of the third temperature measurement pattern 13, like the length of the long side of the first temperature measurement pattern 11, is longer than the wavelength of infrared light, longer than the minimum spatial resolution of infrared thermography, or longer than the minimum spot diameter of an infrared radiation thermometer, and is optimally the same as the size of the minimum spatial resolution or the minimum spot diameter. In the first embodiment, the long side of the third temperature measurement pattern 13 is an L-shaped portion. Similarly to the thickness of the first temperature-measuring pattern 11, the thickness of the third temperature-measuring pattern 13 is several tens of μm or less, preferably several μm or less.

[0032] In the second conductor pattern 3, temperature measurement at the bend 3b, where the current density is high and the temperature rise is higher than in the straight portion of the line 3a, can be performed with high accuracy by detecting infrared rays emitted from the surface of the third temperature measurement pattern 13 using an infrared thermograph or an infrared radiation thermometer.

[0033] At this time, since the third temperature-measuring pattern 13 is formed locally on the surface of the bent portion 3b, it does not increase electrical loss, so that the effect on high-frequency loss can be suppressed and the high-frequency characteristics in the high-frequency circuit can be maintained. Furthermore, when a high-frequency current flows through the second conductor pattern 3, the electric field strength becomes high along the side, i.e., at the edge, of the bent portion 3b. Therefore, the third temperature-measuring pattern 13 is formed to avoid the edge of the bent portion 3b, and therefore there is no increase in electrical loss to the high-frequency circuit.

[0034] In FIG. 1, no temperature measurement pattern is shown in the straight portion of the line 3a in the second conductor pattern 3. However, just as the first temperature measurement pattern 11 is formed on the surface of the line 2a in the first conductor pattern 2, one or more first temperature measurement patterns 11 are locally arranged on the inside surface of the straight portion of the line 3a at locations where it is desired to measure the temperature of the line 3a.

[0035] The fourth temperature-measuring pattern 14 is formed on the surface of the insulating substrate 1 along one side of the line 2a of the first conductor pattern 2 and spaced apart from the surface. That is, the fourth temperature-measuring pattern 14 is locally disposed on the surface of the insulating substrate 1 facing one side of the line 2a at a distance so as to avoid the edge of the line 2a.

[0036] The fifth temperature-measuring pattern 15 is formed in a rectangular shape on the surface of the insulating substrate 1 along the other side of the line 2 a of the first conductor pattern 2 at a distance therefrom. That is, the fifth temperature-measuring pattern 15 is locally arranged on the surface of the insulating substrate 1 facing and spaced apart from the other side of the line 2a so as to avoid the edge of the line 2a.

[0037] The length of the long side of each of the fourth temperature measurement pattern 14 and the fifth temperature measurement pattern 15, like the length of the long side of the first temperature measurement pattern 11, is longer than the wavelength of infrared light, longer than the minimum spatial resolution of infrared thermography, or longer than the minimum spot diameter of an infrared radiation thermometer, and is optimally the same as the size of the minimum spatial resolution or the minimum spot diameter. Similarly to the thickness of the first temperature-measurement pattern 11, the thickness of each of the fourth temperature-measurement pattern 14 and the fifth temperature-measurement pattern 15 is several tens of μm or less, preferably several μm or less.

[0038] Heat is conducted from the high temperature portion of the line 2a of the first conductor pattern 2 to the surface of the insulating substrate 1, and the temperature of the surface of the insulating substrate 1 which has risen in temperature can be measured with high accuracy by detecting the infrared rays radiated from the surfaces of the fourth temperature-measuring pattern 14 and the fifth temperature-measuring pattern 15 with an infrared thermograph or an infrared radiation thermometer.

[0039] At this time, since the fourth temperature-measurement pattern 14 and the fifth temperature-measurement pattern 15 are each formed locally on the surface of the insulating substrate 1, they do not increase electrical loss, thereby suppressing the effect on high-frequency loss and maintaining the high-frequency characteristics in the high-frequency circuit. Furthermore, when a high-frequency current flows through the first conductor pattern 2, the electric field strength becomes high along the sides, i.e., at the edges, of the line 2a. Therefore, the fourth temperature-measuring pattern 14 and the fifth temperature-measuring pattern 15 are formed on the surface of the insulating substrate 1 to avoid the edges of the line 2a, and therefore there is no increase in electrical loss to the high-frequency circuit.

[0040] In FIG. 1, one each of the fourth temperature measurement pattern 14 and the fifth temperature measurement pattern 15 is shown, but if there are multiple locations where it is desired to measure the temperature on the surface of the insulating substrate 1 near the line 2a, multiple fourth temperature measurement patterns 14 and multiple fifth temperature measurement patterns 15 are locally arranged on the surface of the insulating substrate 1 near the line 2a corresponding to each of the multiple locations. The fourth temperature-measurement pattern 14 and the fifth temperature-measurement pattern 15 are desirably formed locally at positions spaced apart along the sides of the portion of the line 2a, which is the heat dissipation source, that has high thermal resistance or high loss density.

[0041] In addition, in FIG. 1, no temperature measurement patterns are shown in the straight portion of the line 3a in the second conductor pattern 3, but just as the fourth temperature measurement pattern 14 and the fifth temperature measurement pattern 15 are formed on the surface of the insulating substrate 1 at a distance from each other on both sides of the line 2a of the first conductor pattern 2, one or more fourth temperature measurement patterns 14 and one or more fifth temperature measurement patterns 15 are locally arranged on the surface of the insulating substrate 1 at a distance from each other on both sides of the straight portion of the line 3a in the second conductor pattern 3 at a location where it is desired to measure the temperature of the surface of the insulating substrate 1 near the straight portion of the line 3a.

[0042] Next, the measurement of the surface temperatures of the first conductor pattern 2 and the second conductor pattern 3, and the surface temperature of the insulating substrate 1 in the vicinity of the first conductor pattern 2, using infrared thermography will be described. As a preliminary preparation, the infrared emissivities of the first temperature measurement pattern 11 to the fifth temperature measurement pattern 15 are set in the infrared thermograph.

[0043] Next, the high frequency circuit mounted on the electric circuit board is operated, whereby high frequency current flows through the first conductor pattern 2 and the second conductor pattern 3, and heat is generated in the first conductor pattern 2 and the second conductor pattern 3 due to conductor loss and dielectric loss. As a result, the surface temperatures of the first conductor pattern 2 and the second conductor pattern 3 rise, and the surface temperatures of the first temperature-measurement pattern 11 to the fifth temperature-measurement pattern 15 also rise.

[0044] By using infrared thermography to capture images of the surfaces of each of the first temperature measurement pattern 11 to the fifth temperature measurement pattern 15, the infrared thermography detects the infrared rays emitted from the surfaces of each of the first temperature measurement pattern 11 to the fifth temperature measurement pattern 15, and the temperature distribution obtained by converting the detected amount of infrared rays into thermal energy is visualized as image information and displayed on a display device.

[0045] In other words, by using infrared thermography to measure the surface temperature of each of the first temperature measurement pattern 11 to the fifth temperature measurement pattern 15 in a non-contact manner, the surface temperatures of set positions on each of the first conductor pattern 2, the second conductor pattern 3, and the insulating substrate 1 can be measured in real time with high accuracy.

[0046] Infrared thermography not only displays the measured temperature information as image information, but also stores the measured temperature information as digital data in a storage means, making it possible to obtain the temperature information as data.

[0047] As described above, the electric circuit board of embodiment 1 has conductor patterns 2, 3 through which high-frequency current flows formed on the surface of insulating substrate 1, and is provided on the surface of insulating substrate 1 with temperature-measuring patterns 11-15 having infrared emissivity higher than that of conductor patterns 2, 3. Therefore, by detecting infrared rays radiated from the surfaces of temperature-measuring patterns 11-15, the surface temperature caused by heat generation of conductor patterns 2, 3 can be measured with high accuracy.

[0048] In the electric circuit board according to the first embodiment, solder resist patterns made of either resin or ceramics are locally arranged as temperature measurement patterns 11-15, so that temperature measurement patterns 11-15 do not increase electrical loss in the high-frequency circuit. In addition, since the temperature measurement patterns 11 to 15 are formed at a distance from both sides of the conductor patterns 2 and 3, the edges of the conductor patterns 2 and 3 where the electric field strength is high can be avoided, and the temperature measurement patterns 11 to 15 do not increase electrical loss in the high-frequency circuit.

[0049] In the first temperature-measurement pattern 11, the surface temperature of the first conductor pattern 2, which is likely to generate heat, can be measured with high accuracy. Since the second temperature-measuring pattern 12 is formed on the surface of the thin line portion 2b of the first conductor pattern 2, the surface temperature of the thin line portion 2b, which is likely to generate heat, can be measured with high accuracy. Since the third temperature-measuring pattern 13 is formed on the surface of the bent portion 3b of the second conductor pattern 3, the surface temperature of the bent portion 3b, which is likely to generate heat, can be measured with high accuracy. In each of the fourth temperature-measurement pattern 14 and the fifth temperature-measurement pattern 15, the surface temperature of the insulating substrate 1, which is susceptible to heat generation, can be measured with high accuracy.

[0050] Furthermore, even if a problem occurs during use of the electric circuit board of embodiment 1, the surface temperatures of the conductor patterns 2, 3 and the insulating substrate 1 can be measured in real time in a non-contact manner using an infrared thermograph or an infrared radiation thermometer using temperature measurement patterns 11-15.

[0051] Embodiment 2 Second Embodiment An electric circuit board according to a second embodiment will be described with reference to FIG. The electric circuit board according to the second embodiment is an electric circuit board on which a high-frequency circuit is mounted, and in which a conductor pattern 5 having an open stub 6 is formed on the surface of an insulating substrate 1. The electric circuit board according to the second embodiment includes an insulating substrate 1, a third conductor pattern 5 having an open stub 6, a ground conductor 4, and sixth to ninth patterns 21 to 24 for temperature measurement.

[0052] A third conductor pattern 5 having an open stub 6 is formed on the front surface of the insulating substrate 1, and a ground conductor 4 is formed on the rear surface of the insulating substrate 1. The open stub 6 is a quarter-wave open stub for a high-frequency signal input to the third conductor pattern 5 . The third conductor pattern 5 is a microstrip line formed between the third conductor pattern 5 and the ground conductor 4 . The third conductor pattern 5 may form a coplanar line or a differential line.

[0053] The third conductor pattern 5, like the first conductor pattern 2 and the second conductor pattern 3, is made of a metal such as copper or gold, and is formed on the surface of the insulating substrate 1 with its metal surface exposed. As shown in FIG. 3, the third conductor pattern 5 has a line 5a with a characteristic impedance of 50Ω and an open stub 6 extended from the line 5a. The angle between the line 5a and the open stub 6 is 90 degrees. That is, the open stub 6 and the line 5a have a T-shape in plan view.

[0054] The length of the open stub 6 is a quarter of the wavelength of the high-frequency signal applied to the third conductor pattern 5 . That is, the length from intersection 5b of open stub 6 and line 5a in third conductor pattern 5 to the tip of open stub 6 is one-quarter of the wavelength of the high-frequency signal.

[0055] As indicated by an arrow B in FIG. 3, a high-frequency signal is incident on the third conductor pattern 5 from the left side in the figure. When a high-frequency signal is input to the third conductor pattern 5, a high-frequency current due to the high-frequency signal flows, causing the third conductor pattern 5 to generate heat due to conductor loss and dielectric loss, resulting in a rise in temperature. The conductor loss in the third conductor pattern 5 is due to the current amplitude caused by the high-frequency signal, and the dielectric loss in the third conductor pattern 5 is due to the electric field amplitude (voltage amplitude) caused by the high-frequency signal.

[0056] It should be noted that the high-frequency signal incident from the left side in the figure is hardly transmitted from intersection 5b between open stub 6 and line 5a of third conductor pattern 5 to line 5a on the right side in the figure. As a result, the line 5a on the right side of the intersection 5b in the figure generates almost no heat due to the high frequency signal.

[0057] Each of the sixth temperature measurement pattern 21 to the ninth temperature measurement pattern 24, like each of the first temperature measurement pattern 11 to the fifth temperature measurement pattern 15, is formed of a solder resist pattern made of an insulating material such as resin or ceramics. Each of the sixth temperature-measurement pattern 21 to the ninth temperature-measurement pattern 24 is formed locally on the surface of the third conductor pattern 5 with the surface of the solder resist exposed.

[0058] The sixth temperature-measuring pattern 21 is formed in a rectangular shape on the surface of the tip of the open stub 6 and spaced apart from each other on both sides of the open stub 6 . That is, the sixth temperature measurement pattern 21 is locally disposed on the inside of the surface of the tip of the open stub 6 so as to avoid the edge of the open stub 6 . When a high-frequency signal is transmitted to the open stub 6, the electric field amplitude (voltage amplitude) of the standing wave due to the high-frequency signal reaches a maximum at the tip of the open stub 6, increasing the dielectric loss and raising concerns about heat generation.

[0059] The length of the long side of the sixth temperature-measurement pattern 21, like that of the first temperature-measurement pattern 11, is longer than the wavelength of infrared light, longer than the minimum spatial resolution of infrared thermography, or longer than the minimum spot diameter of an infrared radiation thermometer, and is optimally the same as the size of the minimum spatial resolution or the minimum spot diameter. Similarly to the thickness of the first temperature-measuring pattern 11, the thickness of the sixth temperature-measuring pattern 21 is several tens of μm or less, preferably several μm or less.

[0060] In the open stub 6 in the third conductor pattern 5, the temperature of the open stub 6 increases due to dielectric loss, so that temperature measurement in the open stub 6 can be performed with high accuracy by detecting infrared rays radiated from the surface of the sixth temperature-measuring pattern 21 using an infrared thermograph or an infrared radiation thermometer.

[0061] In this case, since the sixth temperature measurement pattern 21 is formed locally on the surface of the tip of the open stub 6, it does not increase electrical loss, thereby suppressing the effect on high-frequency loss and maintaining the characteristics of the open stub 6 and the high-frequency characteristics in the high-frequency circuit. Furthermore, when a high-frequency current flows through open stub 6, the electric field strength becomes high along the side of the tip of open stub 6, i.e., at the edge. Therefore, since sixth temperature-measuring pattern 21 is formed to avoid the edge of the tip of open stub 6, there is no increase in electrical loss to the high-frequency circuit.

[0062] The seventh temperature measurement pattern 22 is formed in a rectangular shape on the surface of the open stub 6 at a position 1 / 8 of the wavelength of the high-frequency signal transmitted through the third conductor pattern 5 from the tip of the open stub 6, spaced apart on both sides of the open stub 6. That is, the seventh temperature measurement pattern 22 is locally disposed on the inside of the surface of the open stub 6 so as to avoid the edge of the open stub 6 . When a high-frequency signal is transmitted to open stub 6, the current amplitude of the standing wave due to the high-frequency signal becomes maximum at a position 1 / 8 of the wavelength of the high-frequency signal from the tip of open stub 6, resulting in high conductor loss and raising concerns about heat generation.

[0063] The length of the long side of the seventh temperature-measurement pattern 22, like the length of the long side of the first temperature-measurement pattern 11, is longer than the wavelength of infrared light, longer than the minimum spatial resolution of infrared thermography, or longer than the minimum spot diameter of an infrared radiation thermometer, and optimally is the same as the size of the minimum spatial resolution or the minimum spot diameter. Similarly to the thickness of the first temperature-measuring pattern 11, the seventh temperature-measuring pattern 22 has a thickness of several tens of μm or less, preferably several μm or less.

[0064] In the open stub 6 of the third conductor pattern 5, the temperature of the open stub 6 increases due to conductor loss, so that temperature measurement in the open stub 6 can be performed with high accuracy by detecting infrared rays radiated from the surface of the seventh temperature-measuring pattern 22 with an infrared thermograph or an infrared radiation thermometer.

[0065] In this case, the seventh temperature measurement pattern 22 is formed locally on the surface at a position 1 / 8 wavelength of the high-frequency signal away from the tip of the open stub 6, so that it does not increase electrical loss, thereby suppressing the effect on high-frequency loss and maintaining the characteristics of the open stub 6 and the high-frequency characteristics in the high-frequency circuit. Furthermore, when a high-frequency current flows through open stub 6, the electric field strength becomes high along the sides, i.e., at the edges, of open stub 6. Therefore, seventh temperature-measuring pattern 22 is formed to avoid the edges of open stub 6, and therefore does not increase electrical loss in the high-frequency circuit.

[0066] The eighth temperature measurement pattern 23 is formed on the surface of the line 5a at the intersection 5b between the open stub 6 and the line 5a in the third conductor pattern 5, spaced apart from both sides of the line 5a and the open stub 6, and has an L-shaped planar shape along the sides that form the interior angle (hereinafter simply referred to as the interior angle) between the line 5a and the open stub 6 through which a high-frequency signal is incident on the open stub 6. The eighth temperature measurement pattern 23 is locally arranged on the inside at the inner corner side so as to avoid the edges of the lines 5a around the intersection 5b and the edges of the open stubs 6.

[0067] The position of intersection 5b is a quarter (two-eighths) of the wavelength of the high-frequency signal from the tip of open stub 6. When a high-frequency signal is transmitted to open stub 6, at line 5a at a quarter wavelength of the high-frequency signal from the tip of open stub 6, the electric field amplitude of the standing wave due to the high-frequency signal reaches its maximum, resulting in increased dielectric loss and raising concerns about heat generation.

[0068] The length of the long side of the eighth temperature-measurement pattern 23, like the length of the long side of the first temperature-measurement pattern 11, is longer than the wavelength of infrared light, longer than the minimum spatial resolution of infrared thermography, or longer than the minimum spot diameter of an infrared radiation thermometer, and optimally is the same as the size of the minimum spatial resolution or the minimum spot diameter. In the second embodiment, the long side of the eighth temperature-measuring pattern 23 is an L-shaped portion. Similarly to the thickness of the first temperature-measuring pattern 11, the thickness of the eighth temperature-measuring pattern 23 is several tens of μm or less, preferably several μm or less.

[0069] In the third conductor pattern 5, the temperature of the line 5a at the intersection 5b where the temperature becomes high due to dielectric loss can be measured with high accuracy by detecting infrared rays emitted from the surface of the eighth temperature measurement pattern 23 using an infrared thermograph or an infrared radiation thermometer.

[0070] In this case, since the eighth temperature measurement pattern 23 is formed locally on the surface of the line 5a at the position of the intersection 5b, it does not increase electrical loss, thereby suppressing the effect on high-frequency loss and maintaining the high-frequency characteristics in the high-frequency circuit. Moreover, when a high-frequency current flows through the third conductor pattern 5, the eighth temperature-measuring pattern 23 is formed on the inner corner side to avoid the edge, so that electrical loss to the high-frequency circuit is not increased.

[0071] The ninth temperature measurement pattern 24 is formed in a rectangular shape on the surface of the line 5a at a position 1 / 8 of the wavelength of the high-frequency signal away from the intersection 5b between the open stub 6 and the line 5a in the third conductor pattern 5 on the side where the high-frequency signal is incident, and is spaced apart on both sides of the line 5a. That is, the ninth temperature measurement pattern 24 is locally positioned on the inside of the surface of the third conductor pattern 5 so as to avoid the edge of the third conductor pattern 5 at a position 3 / 8 of a wavelength away from the tip of the open stub 6 in the direction in which the high-frequency signal is incident on the third conductor pattern 5. When a high-frequency signal is transmitted to the third conductor pattern 5, the current amplitude of the standing wave due to the high-frequency signal becomes maximum at a position 3 / 8 of the wavelength of the high-frequency signal from the tip of the open stub 6, resulting in large conductor loss and raising concerns about heat generation.

[0072] The length of the long side of the ninth temperature measurement pattern 24, like the length of the long side of the first temperature measurement pattern 11, is longer than the wavelength of infrared light, longer than the minimum spatial resolution of infrared thermography, or longer than the minimum spot diameter of an infrared radiation thermometer, and optimally is the same as the size of the minimum spatial resolution or the minimum spot diameter. Similarly to the thickness of the first temperature-measuring pattern 11, the thickness of the ninth temperature-measuring pattern 24 is several tens of μm or less, preferably several μm or less.

[0073] In the third conductor pattern 5, the temperature of the line 5a, where the temperature becomes high due to conductor loss, can be measured with high accuracy by detecting infrared rays radiated from the surface of the ninth temperature-measuring pattern 24 with an infrared thermograph or an infrared radiation thermometer.

[0074] In this case, the ninth temperature measurement pattern 24 is formed locally on the surface at a position 3 / 8 of the wavelength of the high-frequency signal from the tip of the open stub 6, so that it does not increase electrical loss, thereby suppressing the effect on high-frequency loss and maintaining the high-frequency characteristics in the high-frequency circuit. Furthermore, when a high-frequency current flows through the line 5a, the electric field strength becomes high along the sides, i.e., at the edges, of the line 5a. Therefore, the ninth temperature-measuring pattern 24 is formed to avoid the edges of the line 5a, and therefore does not increase electrical loss in the high-frequency circuit.

[0075] In the electric circuit board of embodiment 2, temperature measurement patterns 21 to 24 are locally formed on the surface of the tip of the open stub 6 and on the surface of the third conductor pattern 5 at positions spaced apart by 1 / 8 of the wavelength of the high-frequency signal on the side where the high-frequency signal is incident from the tip of the open stub 6.

[0076] In FIG. 3, temperature measurement patterns are not shown on the surface of the insulating substrate 1 spaced apart along both sides of the line 5a in the third conductor pattern 5 on the side where the high-frequency signal is incident from the intersection 5b between the open stub 6 and the line 5a in the third conductor pattern 5. However, similar to the fourth temperature measurement pattern 14 and the fifth temperature measurement pattern 15, the temperature measurement patterns are locally arranged on the surface of the insulating substrate 1 at a position away from the intersection 5b between the open stub 6 and the line 5a in the third conductor pattern 5 on the side where the high-frequency signal is incident, which is 1 / 8 of the wavelength of the high-frequency signal.

[0077] The surface temperature of the third conductor pattern 5 is measured using infrared thermography in the same manner as the surface temperatures of the first conductor pattern 2 and the second conductor pattern 3 are measured. That is, the high frequency circuit mounted on the electric circuit board is operated, and the surfaces of the sixth to ninth temperature measurement patterns 21 to 24 are imaged by infrared thermography.

[0078] The infrared thermography detects infrared rays emitted from the surfaces of each of the sixth temperature measurement patterns 21 to the ninth temperature measurement patterns 24, and visualizes the temperature distribution by converting the detected amount of infrared rays into thermal energy as image information and displays it on a display device. As a result, the surface temperature at a set position on the third conductor pattern 5 can be measured in real time with high accuracy in a non-contact state.

[0079] As described above, the electric circuit board of embodiment 2 has a conductor pattern 5 having an open stub 6 of a quarter wavelength of a high-frequency signal formed on the surface of an insulating substrate 1, and locally includes temperature-measuring patterns 21-24, the infrared emissivity of which is higher than that of the third conductor pattern 5, on the surface of the tip of the open stub 6 and on the surface of the third conductor pattern 5 at a position 1 / 8 of the wavelength of the high-frequency signal away from the tip of the open stub 6 toward the side where the high-frequency signal is incident. Therefore, by detecting infrared rays radiated from the surfaces of the temperature-measuring patterns 21-24, the surface temperature due to heat generation of the third conductor pattern 5 including the open stub 6 can be measured with high accuracy.

[0080] Moreover, as described in the first embodiment, the electric circuit board according to the second embodiment, like the electric circuit board according to the first embodiment, can measure the surface temperature of the third conductor pattern 5 including the open stub 6 which is likely to generate heat, with high accuracy, without increasing the electrical loss to the high-frequency circuit due to the temperature-measuring patterns 21-24. Furthermore, in the electric circuit board according to the second embodiment, even if a problem occurs during use, the surface temperature of the third conductor pattern 5 can be measured in real time in a non-contact state using an infrared thermograph or an infrared radiation thermometer by using the temperature measurement patterns 21 to 24.

[0081] In the electric circuit board according to the second embodiment, an electric circuit board is shown in which a conductor pattern 5 having an open stub 6 with a quarter wavelength of a high-frequency signal is formed on the surface of an insulating substrate 1. However, in an electric circuit board that utilizes a standing wave on a high-frequency circuit such as a short stub or a resonator, a temperature measurement pattern may be formed on the surface of the conductor pattern where the voltage amplitude or current amplitude of the standing wave is maximum.

[0082] In short, in an electric circuit board in which a standing wave due to a high-frequency signal appears in a conductor pattern, by forming a temperature measurement pattern on the surface of a portion of the conductor pattern where the current amplitude or voltage amplitude of the standing wave due to the high-frequency signal appearing on the conductor pattern is large, the surface temperature of the conductor pattern, which is a concern for heat generation, can be measured with high accuracy without increasing the electrical loss to the high-frequency circuit due to the temperature measurement pattern.

[0083] It should be noted that the embodiments may be freely combined, or any of the components in each embodiment may be modified, or any of the components in each embodiment may be omitted. [Industrial Applicability]

[0084] The electric circuit board according to the present disclosure is suitable for use as an electric circuit board having a built-in high-frequency circuit. [Explanation of symbols]

[0085] 1 insulating substrate, 2 first conductor pattern, 2a line, 2b thin line portion, 3 second conductor pattern, 3a line, 3b bend portion, 4 ground conductor, 5 conductor pattern, 6 open stub, 11-15 first temperature measurement pattern to fifth temperature measurement pattern, 21-24 sixth temperature measurement pattern to ninth temperature measurement pattern.

Claims

1. An insulating substrate; a conductor pattern formed on a surface of the insulating substrate and into which a high-frequency signal is incident; a temperature measuring pattern formed on a surface of the insulating substrate, the temperature measuring pattern having an infrared emissivity higher than that of the conductor pattern; An electric circuit board comprising:

2. 2. The electric circuit board according to claim 1, wherein the temperature measurement pattern is a solder resist pattern made of either resin or ceramics.

3. 2. The electric circuit board according to claim 1, wherein the formation of the temperature-measuring pattern on the surface of the insulating substrate is such that a first temperature-measuring pattern is formed on the surface of the conductor pattern at a distance from both sides of the conductor pattern.

4. 4. The electric circuit board according to claim 3, wherein the position of the first temperature-measuring pattern formed on the surface of the insulating substrate is a portion of the conductor pattern having a large thermal resistance or a large loss density.

5. The conductor pattern has a thin line portion having a narrow line width, 2. The electric circuit board according to claim 1, wherein the formation of the temperature-measuring pattern on the surface of the insulating substrate is such that a second temperature-measuring pattern is formed on the surface of the thin line portion of the conductor pattern, spaced apart from both sides of the thin line portion of the conductor pattern.

6. The conductor pattern has a bent portion where a line is bent, 2. The electric circuit board according to claim 1, wherein the formation of the temperature-measuring pattern on the surface of the insulating substrate is such that a third temperature-measuring pattern is formed on the surface of the bent portion of the conductor pattern, spaced apart from both sides of the bent portion of the conductor pattern.

7. 7. The electric circuit board according to claim 6, wherein the third temperature-measuring pattern is positioned on an inner corner side of a bent portion of the conductor pattern.

8. 2. The electric circuit board according to claim 1, wherein the formation of the temperature-measuring pattern on the surface of the insulating substrate is such that a fourth temperature-measuring pattern is formed on the surface of the insulating substrate at a distance along one side of the conductor pattern.

9. 9. The electric circuit board according to claim 8, wherein the position of the fourth temperature-measuring pattern formed on the surface of the insulating substrate is a position separated along one side of a portion of the conductor pattern having a high thermal resistance or a portion of the conductor pattern having a high loss density.

10. The conductor pattern has an open stub, 2. The electric circuit board according to claim 1, wherein the formation of the temperature measurement patterns on the surface of the insulating substrate is such that a sixth temperature measurement pattern is formed on the surface of the tip of the open stub, and a seventh temperature measurement pattern is formed on the surface of the open stub at a position that is 1 / 8 of the wavelength of the high-frequency signal that is passed from the tip of the open stub to the conductor pattern.

11. 11. The electric circuit board according to claim 10, wherein the formation of the temperature measurement pattern on the surface of the insulating substrate further comprises forming an eighth temperature measurement pattern on the surface of the line at an intersection between the open stub and the line in the conductor pattern.

12. 12. The electric circuit board according to claim 11, wherein the formation of the temperature measurement pattern on the surface of the insulating substrate further comprises forming a ninth temperature measurement pattern on the surface of the line in the conductor pattern at a position ⅛ of the wavelength of a high-frequency signal on the side where the high-frequency signal is incident from the intersection of the open stub and the line in the conductor pattern.

13. An electric circuit board in which a standing wave due to a high-frequency signal appears in the conductor pattern, 2. The electric circuit board according to claim 1, wherein the position of the temperature measurement pattern formed on the surface of the insulating substrate is on the surface of a portion of the conductor pattern where a current amplitude or voltage amplitude of a standing wave due to a high frequency signal appearing on the conductor pattern is large.

14. 14. The electric circuit board according to claim 1, wherein a length of the temperature measurement pattern is equal to or longer than the wavelength of infrared light.

15. 14. The electric circuit board according to claim 1, wherein a length of the temperature measurement pattern is equal to or greater than a minimum spatial resolution of an infrared thermography that detects infrared rays emitted from a surface of the temperature measurement pattern to detect temperature.

16. 14. The electric circuit board according to claim 1, wherein a length of the temperature measurement pattern is a length of a minimum spatial resolution of an infrared thermography that detects infrared rays emitted from a surface of the temperature measurement pattern to detect temperature.

17. 14. The electric circuit board according to claim 1, wherein a length of the temperature measurement pattern is equal to or greater than a minimum spot diameter of an infrared radiation thermometer that detects infrared rays radiated from a surface of the temperature measurement pattern to detect temperature.

18. 14. The electric circuit board according to claim 1, wherein a length of the temperature measurement pattern is a length of a minimum spot diameter of an infrared radiation thermometer that detects infrared rays radiated from a surface of the temperature measurement pattern to detect temperature.

19. a ground conductor formed on a rear surface of the insulating substrate; The electric circuit board according to claim 1 , wherein the conductor pattern faces the ground conductor and constitutes a microstrip line.

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