JP2011133442A

JP2011133442A - Humidity sensor

Info

Publication number: JP2011133442A
Application number: JP2009295557A
Authority: JP
Inventors: Takashi Sato; 崇佐藤; Yasuyuki Hattori; ▲靖▼之服部; Tadashi Sakashita; 忠坂下
Original assignee: Alps Electric Co Ltd
Current assignee: Alps Alpine Co Ltd
Priority date: 2009-12-25
Filing date: 2009-12-25
Publication date: 2011-07-07

Abstract

<P>PROBLEM TO BE SOLVED: To provide a humidity sensor capable of measuring correct psychrometry hard to be influenced from heat discharged from electronic components arranged on a same substrate for the humidity sensor element. <P>SOLUTION: Of the humidity sensor mounting a humidity sensor element measuring humidity change, an element peripheral circuit containing electronic components discharging heat at the time of operation and a connector connecting the humidity sensor element and the element peripheral circuit with an external circuit on the same substrate, the humidity sensor element and the electronic components are deployed on each of both front-back sides of the substrate at a position so as to be not overlapped superficially each other. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

本発明は、湿度変化を測定する湿度センサに関する。 The present invention relates to a humidity sensor that measures a change in humidity.

従来から、湿度変化を測定する湿度センサが知られている。しかし、湿度センサ素子とその周辺回路を同一の基板上に搭載しようとすると、例えばオペアンプ、抵抗やコイルなど動作時に熱を発する電子部品が湿度センサ素子の近くに配置されている場合に、該電子部品から発せられる熱により湿度センサ素子周辺の温度が上昇する。 Conventionally, humidity sensors that measure humidity changes are known. However, if an attempt is made to mount the humidity sensor element and its peripheral circuit on the same substrate, for example, when an electronic component that generates heat during operation, such as an operational amplifier, a resistor, or a coil, is disposed near the humidity sensor element, the electronic device The temperature around the humidity sensor element rises due to the heat generated from the parts.

特開昭６１−１２５１５７号公報JP-A-61-125157 特開２００８−２４１６０３号公報JP 2008-241603 A 特開２００９−２３１６０６号公報JP 2009-231606 A

電子部品から発せられる熱により湿度センサ素子周辺の温度が上昇すると、湿度センサ素子周辺の相対湿度が下がり、正確な湿度測定ができなかった。特許文献１は、電子部品からの熱による温度上昇を抑制するため、局部冷却が可能な冷却用集積素子を基板上に搭載しているが、基板の拡大やコスト増加を招くため好ましくない。 When the temperature around the humidity sensor element rises due to the heat generated from the electronic components, the relative humidity around the humidity sensor element decreases, and accurate humidity measurement cannot be performed. In Patent Document 1, a cooling integrated element capable of local cooling is mounted on a substrate in order to suppress a temperature rise due to heat from an electronic component, but this is not preferable because the substrate is enlarged and costs are increased.

特許文献２には、基板のセンサ部を設けた側とは反対側の面に発熱部を備えた湿度センサ装置が記載されているが、発熱部は、センサ部を構成する感湿膜中の水分量を調整して特定の湿度状態を作り出す機能を有するもの、すなわち、センサ部に熱を与えることを目的とした電子部品であり、この発熱部からの熱がセンサ部に影響しないようにする手段は開示されていない。また、特許文献３には、発熱部品の実装に伴う温度上昇によるＬＳＩの誤作動を回避するため、第１の面にデジタル部品を実装し、この第１の面と対向する第２の面にアナログ部品を実装した電子回路基板が記載されているが、湿度センサにおいて湿度センサ素子部と周辺回路をどのように配置するかの具体的な記載はない。 Patent Document 2 describes a humidity sensor device having a heat generating part on the surface opposite to the side where the sensor part of the substrate is provided. The heat generating part is included in the moisture sensitive film constituting the sensor part. An electronic component that has the function of adjusting the amount of moisture to create a specific humidity state, that is, an electronic component intended to give heat to the sensor unit, so that the heat from the heat generating unit does not affect the sensor unit Means are not disclosed. Further, in Patent Document 3, a digital component is mounted on the first surface and the second surface opposite to the first surface in order to avoid a malfunction of the LSI due to a temperature rise accompanying mounting of the heat generating component. Although an electronic circuit board on which analog parts are mounted is described, there is no specific description on how to arrange the humidity sensor element portion and the peripheral circuit in the humidity sensor.

本発明は、湿度センサ素子が同一の基板に搭載された電子部品から発せられる熱の影響を受けにくく、正確な湿度測定が可能な湿度センサを得ることを目的とする。 An object of the present invention is to obtain a humidity sensor in which a humidity sensor element is not easily affected by heat generated from an electronic component mounted on the same substrate and is capable of accurate humidity measurement.

本発明は、電子部品からの熱の影響が湿度センサ素子に及ばないように、基板に搭載する湿度センサ素子とその周辺回路（特に動作時に熱を発する電子部品）との最適なレイアウトを提案するものである。 The present invention proposes an optimum layout of a humidity sensor element mounted on a substrate and its peripheral circuit (especially an electronic part that generates heat during operation) so that the influence of heat from the electronic component does not reach the humidity sensor element. Is.

すなわち、本発明は、湿度変化を測定する湿度センサ素子と、動作時に熱を発する電子部品を含む素子周辺回路と、前記湿度センサ素子及び前記素子周辺回路を外部回路に接続させるコネクタとを同一の基板に搭載した湿度センサにおいて、前記湿度センサ素子と前記電子部品は、前記基板の表裏面の一方と他方に、互いに平面的に重複しない位置で設けられていることを特徴としている。 That is, the present invention provides the same humidity sensor element for measuring a change in humidity, an element peripheral circuit including an electronic component that generates heat during operation, and a connector for connecting the humidity sensor element and the element peripheral circuit to an external circuit. In the humidity sensor mounted on the substrate, the humidity sensor element and the electronic component are provided on one and the other of the front and back surfaces of the substrate at positions that do not overlap with each other in a plane.

より具体的には、前記湿度センサ素子は、前記コネクタと平面的な位置を異ならせて、基板の該コネクタを設けた面と同一面に設けられ、前記電子部品は、前記基板のコネクタを設けた側とは反対側の面に、該コネクタと平面的に重複する位置で設けられていることが好ましい。 More specifically, the humidity sensor element has a planar position different from that of the connector, and is provided on the same surface as the surface of the board on which the connector is provided, and the electronic component is provided with the connector on the board. Preferably, it is provided on the surface opposite to the opposite side at a position overlapping the connector in plan view.

前記基板には、前記電子部品の周囲にスルーホールが形成されていることが好ましい。この態様によれば、電子部品から発せられた熱がスルーホールを介して外方へ放出されやすくなる。 It is preferable that a through hole is formed in the substrate around the electronic component. According to this aspect, the heat generated from the electronic component is easily released outward through the through hole.

前記基板の表裏面には、前記湿度センサ素子及び前記素子周辺回路にそれぞれ接続する電気配線パターンが形成されるが、この電気配線パターンは、前記電子部品に接続する電気配線パターンを最も幅狭にすることが好ましい。この態様によれば、電子部品からの熱が電極パターンや基板に伝わるのを極力抑えることができ、湿度センサ素子への影響をより軽減できる。 Electrical wiring patterns connected to the humidity sensor element and the element peripheral circuit are formed on the front and back surfaces of the substrate, respectively, and this electrical wiring pattern has the narrowest electrical wiring pattern connected to the electronic component. It is preferable to do. According to this aspect, it is possible to suppress the heat from the electronic component from being transmitted to the electrode pattern or the substrate as much as possible, and the influence on the humidity sensor element can be further reduced.

本発明によれば、電子部品を湿度センサ素子とは基板表裏面の反対側で平面的に重複しない位置に設けたので、湿度センサ素子が電子部品から発せられる熱の影響を受けにくく、正確な湿度測定が可能な湿度センサを提供できる。 According to the present invention, since the electronic component is provided at a position that does not overlap in plane with the humidity sensor element on the opposite side of the front and back surfaces of the substrate, the humidity sensor element is not easily affected by the heat generated from the electronic component and is accurate. A humidity sensor capable of measuring humidity can be provided.

本発明を適用した湿度センサの一実施形態を示す斜視図である。It is a perspective view showing one embodiment of a humidity sensor to which the present invention is applied. 同湿度センサの平面図である。It is a top view of the humidity sensor. 図２のIII−III線に沿う断面図である。It is sectional drawing which follows the III-III line of FIG. 同湿度センサの基板裏面に形成された配線パターン図である。It is the wiring pattern figure formed in the board | substrate back surface of the same humidity sensor.

図１は本発明を適用した湿度センサの一実施形態を示す斜視図、図２は湿度センサを裏面側から見て示す平面図、図３は図２のIII−III線に沿う断面図、図４は基板裏面に形成された電気配線パターン図である。湿度センサ１は、単一の基板１０に、湿度変化を測定する湿度センサ素子２０と、その周辺回路３０と、外部回路との接続に用いられるコネクタ４０とを搭載して構成されている。 1 is a perspective view showing an embodiment of a humidity sensor to which the present invention is applied, FIG. 2 is a plan view showing the humidity sensor as viewed from the back side, and FIG. 3 is a sectional view taken along line III-III in FIG. 4 is an electric wiring pattern diagram formed on the back surface of the substrate. The humidity sensor 1 is configured by mounting a humidity sensor element 20 for measuring a humidity change, a peripheral circuit 30 thereof, and a connector 40 used for connection to an external circuit on a single substrate 10.

基板１０は、平面矩形状の平板基板である。この基板表面１０ａには、図１に示されるように、湿度センサ素子２０とコネクタ４０が離間して配置され、湿度センサ素子２０の近傍にサーミスタ３１が配置されている。湿度センサ素子２０は、具体的には例えば、吸収または放出した水分量に応じて誘電率が変化する高分子感湿材料を誘電体とし、その誘電率変化を静電容量変化として検出する静電容量型、あるいは、電気抵抗変化として検出するピエゾ抵抗型を用いることができる。サーミスタ３１は、周辺回路３０の発熱しない回路構成要素であって、湿度センサ素子２０の周辺温度を検出する。コネクタ４０は、複数の突起状電極からなるコネクタピンを有しており、コネクタピンの一端部４０ａが基板１０の側方（図１、図３では左方）に突出し、コネクタピンの他端部４０ｂが基板裏面１０ｂに突出している。 The substrate 10 is a flat rectangular substrate. As shown in FIG. 1, the humidity sensor element 20 and the connector 40 are spaced apart from each other on the substrate surface 10 a, and the thermistor 31 is disposed in the vicinity of the humidity sensor element 20. Specifically, the humidity sensor element 20 uses, for example, a polymer moisture-sensitive material whose dielectric constant changes according to the amount of absorbed or released water as a dielectric, and detects the change in the dielectric constant as a capacitance change. A capacitive type or a piezoresistive type that detects an electric resistance change can be used. The thermistor 31 is a circuit component that does not generate heat in the peripheral circuit 30 and detects the ambient temperature of the humidity sensor element 20. The connector 40 has connector pins composed of a plurality of protruding electrodes, and one end portion 40a of the connector pin protrudes to the side of the substrate 10 (left side in FIGS. 1 and 3), and the other end portion of the connector pin. 40b protrudes from the substrate back surface 10b.

基板裏面１０ｂには、図１〜図４に示されるように、上述のサーミスタ３１を除く周辺回路３０の回路構成要素が配置されている。周辺回路３０には、サーミスタ３１のほかに、例えば抵抗、コイル、オペアンプ等の発熱を目的とはしていないものの動作時（通電時）に熱を発する電子部品３２と、例えばコンデンサのように発熱しない回路部品３３と、グランド３４が備えられている。動作時に発熱する電子部品３２は、湿度センサ素子２０から最も遠く離れるように基板１０のコネクタ４０を設けた一端側に寄せて配置され、基板１０を介してコネクタ４０と対向している。この電子部品３１の外周を囲むようにして、基板表裏面１０ａ、１０ｂを貫通する複数のスルーホール１３が基板１０に形成されている。複数のスルーホール１３は、電子部品３１から発せられた熱を基板裏面１０ｂから外方へ拡散させる放熱機能を有している。一方、動作時に発熱しない回路部品３３は、電子部品３２とは離間させて配置されている。具体的に周辺回路３０には、例えば、外部電源から与えられた供給電圧を所定電圧まで降下させて、湿度センサ素子２０への入力電圧を生成する降圧回路などが含まれる。 As shown in FIGS. 1 to 4, circuit components of the peripheral circuit 30 excluding the above-described thermistor 31 are arranged on the substrate back surface 10 b. In addition to the thermistor 31, the peripheral circuit 30 includes, for example, an electronic component 32 that generates heat during operation (when energized), such as a resistor, a coil, and an operational amplifier, and generates heat such as a capacitor. A circuit component 33 and a ground 34 are provided. The electronic component 32 that generates heat during operation is disposed close to one end of the board 10 where the connector 40 is provided so as to be farthest from the humidity sensor element 20, and faces the connector 40 via the board 10. A plurality of through holes 13 penetrating the substrate front and back surfaces 10 a and 10 b are formed in the substrate 10 so as to surround the outer periphery of the electronic component 31. The plurality of through holes 13 have a heat dissipation function for diffusing heat generated from the electronic component 31 outward from the substrate back surface 10b. On the other hand, the circuit component 33 that does not generate heat during operation is disposed away from the electronic component 32. Specifically, the peripheral circuit 30 includes, for example, a step-down circuit that reduces the supply voltage supplied from the external power supply to a predetermined voltage to generate an input voltage to the humidity sensor element 20.

上記湿度センサ素子２０、周辺回路３０（サーミスタ３１、電子部品３２、回路部品３３、グランド３４）及びコネクタ４０は、基板表裏面１０ａ、１０ｂに形成された複数の電気配線パターン１５によりそれぞれ電気的に接続されている。複数の電気配線パターン１５のうち、周辺回路３０の電子部品３２に接続する電気配線パターン１５ａは最も幅狭に形成されており（図４）、電子部品３２からの熱が電気配線パターン１５ａに、また、該電気配線パターン１５ａを介して基板１０に伝わりにくくしてある。 The humidity sensor element 20, peripheral circuit 30 (thermistor 31, electronic component 32, circuit component 33, ground 34) and connector 40 are electrically connected by a plurality of electric wiring patterns 15 formed on the front and back surfaces 10a and 10b of the board, respectively. It is connected. Of the plurality of electrical wiring patterns 15, the electrical wiring pattern 15a connected to the electronic component 32 of the peripheral circuit 30 is formed to be the narrowest (FIG. 4), and heat from the electronic component 32 is transferred to the electrical wiring pattern 15a. Further, it is difficult to transmit to the substrate 10 through the electric wiring pattern 15a.

以上のように本実施形態では、湿度センサ素子２０と発熱する電子部品３２が、基板表面１０ａと基板裏面１０ｂで反対側に位置し、かつ、平面的に重複しない。このように電子部品３２を湿度センサ素子２０から最も遠ざけて配置すれば、同一の基板１０に搭載されていても、基板１０の同一平面に湿度センサ素子２０と電子部品３２を並べて配置した場合に比べて、電子部品３２から発せられた熱が湿度センサ素子２０に伝わりにくくなる。これにより、電子部品３１の発熱による湿度センサ素子２０の周辺の相対湿度変化を抑えられるので、湿度センサ素子２０の正確な湿度測定が可能となる。また、本実施形態のように湿度センサ素子２０と電子部品３２との配置関係に着目して該湿度センサ素子２０に対する熱影響を低減させれば、冷却用素子を設ける必要がなく、基板の大型化及びコスト増加を招くこともない。本実施形態のサーミスタ３１、回路部品３３のように周辺回路３０の発熱しない回路構成要素は、湿度センサ素子２０の湿度測定に悪影響を与えることがないので、湿度センサ素子２０と同一面（基板表面１０ａ）または反対側の面（基板裏面１０ｂ）のいずれに設けてもよい。 As described above, in the present embodiment, the humidity sensor element 20 and the heat generating electronic component 32 are located on the opposite sides of the substrate front surface 10a and the substrate back surface 10b and do not overlap in plan view. If the electronic component 32 is arranged farthest from the humidity sensor element 20 as described above, the humidity sensor element 20 and the electronic component 32 are arranged side by side on the same plane of the substrate 10 even if they are mounted on the same substrate 10. In comparison, the heat generated from the electronic component 32 is less likely to be transmitted to the humidity sensor element 20. Thereby, since the relative humidity change of the periphery of the humidity sensor element 20 by the heat_generation | fever of the electronic component 31 can be suppressed, the accurate humidity measurement of the humidity sensor element 20 is attained. Further, if the thermal influence on the humidity sensor element 20 is reduced by paying attention to the arrangement relationship between the humidity sensor element 20 and the electronic component 32 as in the present embodiment, there is no need to provide a cooling element, and the large size of the substrate. And no increase in cost. Since the circuit components that do not generate heat in the peripheral circuit 30 such as the thermistor 31 and the circuit component 33 of the present embodiment do not adversely affect the humidity measurement of the humidity sensor element 20, the same surface as the humidity sensor element 20 (substrate surface) 10a) or the opposite surface (substrate back surface 10b).

１湿度センサ
１０基板
１０ａ基板表面
１０ｂ基板裏面
１３スルーホール
１５電気配線パターン
２０湿度センサ素子
３０周辺回路
３１電子部品
３２回路構成要素
４０コネクタ DESCRIPTION OF SYMBOLS 1 Humidity sensor 10 Board | substrate 10a Board | substrate surface 10b Board | substrate back surface 13 Through hole 15 Electrical wiring pattern 20 Humidity sensor element 30 Peripheral circuit 31 Electronic component 32 Circuit component 40 Connector

Claims

湿度変化を測定する湿度センサ素子と、動作時に熱を発する電子部品を含む素子周辺回路と、前記湿度センサ素子及び前記素子周辺回路を外部回路に接続させるコネクタとを同一の基板に搭載した湿度センサにおいて、
前記湿度センサ素子と前記電子部品は、前記基板の表裏面の一方と他方に、互いに平面的に重複しない位置で設けられていることを特徴とする湿度センサ。 A humidity sensor in which a humidity sensor element for measuring a humidity change, an element peripheral circuit including an electronic component that generates heat during operation, and a connector for connecting the humidity sensor element and the element peripheral circuit to an external circuit are mounted on the same substrate In
The humidity sensor according to claim 1, wherein the humidity sensor element and the electronic component are provided on one and the other of the front and back surfaces of the substrate at positions that do not overlap with each other in a plane.

請求項１記載の湿度センサにおいて、前記湿度センサ素子は、前記コネクタと平面的な位置を異ならせて、前記基板の該コネクタを設けた面と同一面に設けられ、前記電子部品は、前記基板のコネクタを設けた側とは反対側の面に、該コネクタと平面的に重複する位置で設けられている湿度センサ。 2. The humidity sensor according to claim 1, wherein the humidity sensor element is provided on the same surface as the surface of the substrate on which the connector is provided, with the planar position being different from that of the connector. A humidity sensor provided on a surface opposite to the side where the connector is provided at a position overlapping the connector in a plan view.

請求項１または２記載の湿度センサにおいて、前記基板には、前記電子部品の周囲にスルーホールが形成されている湿度センサ。 3. The humidity sensor according to claim 1, wherein a through hole is formed in the substrate around the electronic component. 4.

請求項１ないし３のいずれか一項に記載の湿度センサにおいて、前記基板の表裏面に形成される前記湿度センサ素子及び前記素子周辺回路にそれぞれ接続する電気配線パターンは、前記電子部品に接続する電気配線パターンが最も幅狭である湿度センサ。 4. The humidity sensor according to claim 1, wherein an electrical wiring pattern connected to each of the humidity sensor element and the element peripheral circuit formed on the front and back surfaces of the substrate is connected to the electronic component. 5. Humidity sensor with the narrowest electrical wiring pattern.