JP5046198B2 - Temperature sensor - Google Patents

Description

  The present invention relates to a temperature sensor for non-contact measurement of the temperature of a heat source.

  Japanese Patent Laid-Open No. 2003-194630 discloses a temperature sensor that measures the temperature of a heat source in a non-contact manner by detecting the amount of heat of infrared rays radiated from the heat source. This type of temperature sensor includes an infrared absorption film that efficiently absorbs infrared rays from a heat source, and a temperature-sensitive element detects an increase in temperature of the infrared absorption film due to infrared reception. The temperature sensing element has a temperature characteristic in which an electrical characteristic changes corresponding to the temperature, and the temperature of the heat source can be estimated based on an electric signal output from the temperature sensing element. As such a temperature sensitive element, a thermistor, a thermopile, a metal temperature measuring element, etc. having resistance temperature characteristics are known. Further, as an infrared absorbing film, a polymer film such as polyimide having a characteristic of absorbing a far-infrared wavelength band is known.

JP 2003-194630 A

  However, since an infrared absorbing film such as a polymer film has a large thermal resistance, the amount of heat distributed in the plane of the infrared absorbing film cannot be efficiently transferred to the temperature sensitive element. For this reason, only the amount of heat stored in a part of the infrared absorption film in contact with the temperature-sensitive element contributes to the temperature rise of the temperature-sensitive element, and the amount of heat distributed over a wide area in the plane of the infrared absorption film is It hardly contributed to the temperature rise of the temperature element.

  Furthermore, the thermal conductivity (400 W / mK) of the lead pattern for taking out an electrical signal from the temperature sensitive element is much higher than the thermal conductivity (0.2 to 0.4 W / mK) of the infrared absorption film. It has been pointed out that the amount of heat that has flowed from the absorption film into the temperature sensitive element flows to the outside through the lead pattern and is one of the factors that cause a temperature decrease of the temperature sensitive element.

  In addition, since the thermal resistance of the heat transfer path from the infrared absorption film to the temperature sensing element is very large, when the temperature of the heat source changes, the temperature sensing element cannot follow the change sensitively, and response characteristics It was also a factor of decline. For this reason, the conventional temperature sensor still has room for investigation in measuring the temperature of the heat source accurately and with good responsiveness.

  Therefore, an object of the present invention is to provide a temperature sensor that solves the above-described problems and can accurately measure the temperature of the heat source with high responsiveness.

In order to solve the above-described problems, a temperature sensor according to the present invention includes an infrared absorption film that generates heat by absorbing infrared rays radiated from a heat source, and an electric power corresponding to the temperature of the heat source by detecting the amount of heat of the infrared absorption film. A temperature-sensitive element that outputs a signal and a heat collection pattern for collecting the amount of heat distributed in the infrared absorption film to the temperature-sensitive element are provided. The temperature sensing element further includes an electrode connected to a lead pattern for outputting an electric signal, and the heat collecting pattern is formed radially in the plane of the infrared absorption film starting from this electrode. The lead pattern and the heat collection pattern are formed in the same film forming process. Since the amount of heat distributed in the infrared absorption film is transferred to the temperature sensitive element quickly through the heat collection pattern, the temperature of the heat source can be measured accurately and with good responsiveness. Further, by making the shape of the heat collection pattern radial, it becomes possible to finely scrape the amount of heat distributed in the infrared absorption film, and the heat collection efficiency can be increased.

  With the temperature sensor according to the present invention, the temperature of the heat source can be measured accurately and with good responsiveness.

3 is an explanatory diagram of a temperature sensor according to Embodiment 1. FIG. It is explanatory drawing of the temperature sensor concerning Example 2. FIG. It is explanatory drawing of the temperature sensor concerning Example 3. FIG. FIG. 10 is an explanatory diagram of a temperature sensor according to a fourth embodiment. 10 is an explanatory diagram of a temperature sensor according to Embodiment 5. FIG. 10 is an explanatory diagram of a temperature sensor according to Embodiment 6. FIG. 10 is an explanatory diagram of a temperature sensor according to Embodiment 7. FIG.

  Embodiments according to the present invention will be described below with reference to the drawings. The same members are denoted by the same reference numerals, and redundant description is omitted. The drawings are schematic, and the ratio of dimensions between members, the shape of the members, and the like may be different from the actual sensor structure within a range where the effects of the present invention can be obtained.

  FIG. 1 is an explanatory diagram of a temperature sensor 100 according to the first embodiment. The temperature sensor 100 absorbs infrared rays radiated from the heat source and generates heat, and the temperature sensing element 10 outputs an electric signal corresponding to the temperature of the heat source by detecting the amount of heat of the infrared absorption film 20. The lead patterns 31 and 32 for outputting an electrical signal from the temperature sensing element 10 and the heat collection pattern 40 for collecting the amount of heat distributed in the infrared absorption film 20 to the temperature sensing element 10 are provided. The material of the infrared absorption film 20 may be any material that generates heat by absorbing radiant infrared rays from a heat source. For example, a material having an absorption spectrum for light in a wavelength band of 4 μm to 10 μm called far infrared rays is desirable. As such a material, a resin made of a polymer material such as fluorine, silicone, polyester, polyimide, polyethylene, polycarbonate, PPS (polyphenylene sulfide) is preferable. The temperature sensing element 10 is not particularly limited as long as it is a sensor element whose electrical characteristics change according to temperature. For example, a thermistor, a thermopile, a metal thermometer having a resistance temperature characteristic, and the like are preferable. It is. The temperature sensing element 10 includes electrodes 11 and 12 connected to the lead patterns 31 and 32, respectively. The change in electrical characteristics corresponding to the temperature change of the temperature sensing element 10 is an electrical signal corresponding to the temperature of the heat source. The lead patterns 31 and 32 are taken out to the outside. When the temperature sensing element 10 is a thermistor having resistance temperature characteristics, for example, the temperature change of the temperature sensing element 10 appears as a resistance value change. By causing a predetermined current to flow through the temperature sensing element 10 in advance, a change in resistance value of the temperature sensing element 10 is detected as a voltage change. The output voltage of the temperature sensing element 10 is signal-processed as an electrical signal corresponding to the temperature of the heat source.

  The heat collection pattern 40 is a heat collection member for capturing the amount of heat distributed in various places of the infrared absorption film 20 and collecting the heat in the temperature sensing element 10. The heat collection pattern 40 captures heat over a wide range not only from the region in the vicinity of the temperature sensing element 10 but also from the region away from the temperature sensing element 10, so that the electrodes 11, 12 can collect heat efficiently. Are formed radially in the plane of the infrared absorption film 20. The heat collection pattern 40 is not a member related to transmission of an electric signal but a member related only to heat conduction, and thus terminates in the plane of the infrared absorption film 20 without being connected to an external component. For this reason, heat does not flow out from the heat collection pattern 40, and heat flows in one direction from the end of the heat collection pattern 40 toward the temperature sensing element 10. The heat collection pattern 40 is a radial pattern that repeats branching from the electrodes 11 and 12 toward the outer peripheral edge of the infrared absorption film 20 in order to uniformly capture the amount of heat stored in various places of the infrared absorption film 20. It is preferable that it is formed. With such a configuration, the amount of heat distributed in the infrared absorption film 20 is scattered in an island shape between the branches of the heat collection pattern 40, and the temperature gradient between the infrared absorption film 20 and the temperature sensing element 10. Thus, a heat flow can be generated toward the temperature sensing element 10. Moreover, by forming the heat collection pattern 40 radially, the heat collection range 50 in which heat can be captured can be expanded to the entire infrared absorption film 20, and the heat collection efficiency can be increased. Further, since the heat transfer path from the root portion of the heat collection pattern 40 (connection portion between the heat collection pattern 40 and the electrodes 11 and 12) to each point of the infrared absorption film 20 can be shortened, the amount of heat distributed in the infrared absorption film 20 Can be quickly collected on the temperature sensing element 10 through a heat transfer path having a low thermal resistance. Thereby, the temperature sensing element 10 can react with high responsiveness to the temperature change of the heat source.

  The amount of heat flowing through the heat collection pattern 40 increases as it approaches the temperature sensing element 10. Therefore, it is preferable to make the heat collection pattern 40 thicker and lower the thermal resistance as it approaches the temperature sensing element 10. Thereby, since the heat collection pattern 40 becomes thinner as the end is approached and the thermal resistance becomes higher, the heat flow toward the end can be suppressed and the heat flow to the temperature sensing element 10 can be promoted. . Further, even when the amount of heat distributed to each point of the infrared absorption film 20 is small, heat is collected through the low resistance heat collection pattern 40 and flows into the temperature sensing element 10, so that the temperature of the temperature sensing element 10 is increased. Decrease can be suppressed and sensitivity characteristics can be enhanced.

  At the time when the infrared rays from the heat source start to be radiated to the infrared absorption film 20, the temperature difference between the temperature sensing element 10 and the infrared absorption film 20 is large, and the temperature gradient from both the heat collection pattern 40 to the temperature sensing element 10. Heat flows in. Then, as the temperature of the temperature sensitive element 10 rises, the temperature gradient becomes smaller, so that the heat flow into the temperature sensitive element 10 decreases. On the other hand, part of the heat collected in the temperature sensing element 10 is dissipated through the lead patterns 31 and 32 and the ambient atmosphere, and the temperature of the temperature sensing element 10 is lowered. The heat inflow continues. Then, when the amount of heat flowing into the temperature sensing element 10 and the amount of heat flowing out of the temperature sensing element 10 are balanced, a thermal equilibrium state is established, and the temperature of the temperature sensing element 10 becomes constant. Note that part of the heat collected by the temperature sensing element 10 flows out to the outside through the lead patterns 31 and 32, so the lead patterns 31 and 32 wired near the outer peripheral end of the infrared absorption film 20. It is preferable to make at least a part of the thin film meander and meander to increase the thermal resistance and suppress the heat outflow to the outside.

  The material of the heat collection pattern 40 should just be a material which has a thermal resistance smaller than the thermal resistance of the infrared rays absorption film 20, and is excellent in thermal conductivity. For example, the material of the heat collection pattern 40 may be the same as or different from the material of the lead patterns 31 and 32. When the material of the heat collection pattern 40 is the same as the material of the lead patterns 31 and 32, there is an advantage that the heat collection pattern 40 and the lead patterns 31 and 32 can be formed in the same film forming process. For example, a copper foil is formed on the infrared absorbing film 20 and patterned into a predetermined shape using a known printing technique, thereby forming the heat collecting pattern 40 and the lead patterns 31 and 32 having conductivity. be able to. When the material of the heat collection pattern 40 is different from the material of the lead patterns 31 and 32, for example, a material having a high thermal conductivity (such as a carbon graphite film) other than metal may be used as the material of the heat collection pattern 40. .

  FIG. 2 is an explanatory diagram of a temperature sensor 200 according to the second embodiment. As shown in the figure, in the heat collecting pattern 40, the stem 41 formed radially from the electrodes 11 and 12 is bent in a bent manner, and the needle-like tip 43 branches from the bent point 42. The first and second embodiments are different from the first embodiment in that the first and second embodiments have a common sensor structure. According to the second embodiment, since the heat collection pattern 40 can be stretched around the space between the trunks 41 by the needle-like tip 43, heat can be finely collected from the heat collection range 50.

  FIG. 3 is an explanatory diagram of a temperature sensor 300 according to the third embodiment. As shown in the figure, the heat collection pattern 40 is formed radially from the electrodes 11 and 12, but the pattern is simplified and is different from the first embodiment. Examples 1 and 3 have a common sensor structure. According to the third embodiment, the temperature sensor 300 can be created by a simple manufacturing process.

  FIG. 4 is an explanatory diagram of a temperature sensor 400 according to the fourth embodiment. As shown in the figure, the heat collection pattern 40 is formed radially without branching from the electrodes 11 and 12, and between the vicinity of the outer peripheral end of the infrared absorption film 20 and the meandering portions of the lead patterns 31 and 32. However, the first and fourth embodiments have a common sensor structure. According to the fourth embodiment, the heat collection efficiency can be improved while simplifying the shape of the heat collection pattern 40.

  FIG. 5 is an explanatory diagram of a temperature sensor 500 according to the fifth embodiment. As shown in the figure, the heat collection pattern 40 is different from the first embodiment in that the heat collection pattern 40 is formed in a radial manner while meandering without branching from the electrodes 11 and 12. 1 and 5 have a common sensor structure. According to the fifth embodiment, the heat collection efficiency can be improved while simplifying the shape of the heat collection pattern 40.

  FIG. 6 is an explanatory diagram of a temperature sensor 600 according to the sixth embodiment. In the figure, reference numeral 601 indicates a point that is present on the infrared absorption film 20 and is in close contact with the bottom of the temperature-sensitive element 10. The heat collection pattern 40 according to the sixth embodiment is different from the first embodiment in that the heat collection pattern 40 is formed radially in the plane of the infrared ray absorbing film 20 starting from the point 601, and in the other points, the first and sixth embodiments are different. It has a common sensor structure. The heat collection pattern 40 according to the sixth embodiment may include a pattern that is formed radially from the electrodes 11 and 12 in addition to a pattern that is formed radially from the point 601, or a point 601 as a starting point. Only those formed in a radial pattern may be included. The heat collection pattern 40 formed radially from the point 601 is not electrically connected to the temperature sensing element 10 and is not connected to the lead patterns 31 and 32. For this reason, the heat collected by the heat collection pattern 40 can be prevented from flowing out via the lead patterns 31 and 32. According to Example 6, the amount of heat distributed in the heat collection range 50 can be finely scraped.

  FIG. 7 is an explanatory diagram of a temperature sensor 700 according to the seventh embodiment. As shown in the figure, the temperature sensor 700 includes a plurality of temperature sensitive elements 10, 60. The plurality of temperature sensing elements 10 and 60 are connected in series, and the heat collection pattern 40 is radially formed on the surface of the infrared absorption film 20 with the connection point 701 of both temperature sensing elements as a starting point. The lead pattern 31 connected to the temperature sensing element 10 and the lead pattern 32 connected to the temperature sensing element 60 are each formed in a straight line in parallel with respect to the connection direction of the plurality of temperature sensing elements 10 and 60, and the thermal resistance. Is configured to be small. Since the heat collection pattern 40 and the lead patterns 31 and 32 are not connected as a metal foil, the amount of heat collected by the heat collection pattern 40 can be prevented from flowing out to the outside through the lead patterns 31 and 32 as a temperature. The sensitivity characteristic of the sensor 700 is improved. For example, when the amount of energy absorbed by the infrared absorption film 20 increases, the temperature sensing elements 10 and 60 rapidly store the amount of heat collected by the heat collection pattern 40, and the temperature rises with high sensitivity. On the other hand, when the amount of energy absorbed by the infrared absorbing film 20 decreases, the amount of heat flows from the temperature sensitive elements 10 and 60 through the lead patterns 31 and 32 having a low thermal resistance to the outside. The temperature drops with high sensitivity. Thereby, both the rising response characteristic and the falling response characteristic of the temperature sensor 700 can be adjusted with good balance. In addition, although the two temperature sensing elements 10 and 60 are illustrated in the figure, the radial heat collection pattern which connected the three or more temperature sensing elements in series and started from the connection point between temperature sensing elements is shown. 40 may be formed.

  The temperature sensor according to the present invention can be applied to an application for non-contact measurement of the temperature of a heat source.

DESCRIPTION OF SYMBOLS 10 ... Temperature sensing element 11, 12 ... Electrode 20 ... Infrared absorption film 31, 32 ... Lead pattern 40 ... Heat collection pattern 50 ... Heat collection range 100, 200, 300, 400, 500, 600, 700 ... Temperature sensor

Claims (1)

An infrared absorbing film that absorbs infrared rays radiated from a heat source and generates heat;
A temperature sensitive element that outputs an electrical signal corresponding to the temperature of the heat source by detecting the amount of heat of the infrared absorption film; and
A heat collection pattern for collecting heat in the infrared absorption film on the thermosensitive element; and
Equipped with a,
The temperature sensing element further includes an electrode connected to a lead pattern for outputting the electrical signal,
The heat collection pattern is formed radially in the plane of the infrared absorption film starting from the electrode,
The lead pattern and the heat collection pattern are temperature sensors formed in the same film forming process .

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