JPH0441765B2 - - Google Patents
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- Publication number
- JPH0441765B2 JPH0441765B2 JP60025233A JP2523385A JPH0441765B2 JP H0441765 B2 JPH0441765 B2 JP H0441765B2 JP 60025233 A JP60025233 A JP 60025233A JP 2523385 A JP2523385 A JP 2523385A JP H0441765 B2 JPH0441765 B2 JP H0441765B2
- Authority
- JP
- Japan
- Prior art keywords
- resistor
- temperature
- substrate
- air flow
- uneven structure
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
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- 239000000758 substrate Substances 0.000 claims description 26
- 238000010438 heat treatment Methods 0.000 claims description 19
- 238000005530 etching Methods 0.000 claims description 16
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 claims description 9
- 229910052710 silicon Inorganic materials 0.000 claims description 9
- 239000010703 silicon Substances 0.000 claims description 9
- 239000013078 crystal Substances 0.000 claims description 8
- 239000012530 fluid Substances 0.000 claims 2
- 230000001419 dependent effect Effects 0.000 description 19
- 239000012528 membrane Substances 0.000 description 15
- 230000007423 decrease Effects 0.000 description 9
- 238000011144 upstream manufacturing Methods 0.000 description 7
- 238000002485 combustion reaction Methods 0.000 description 6
- 230000017525 heat dissipation Effects 0.000 description 6
- 230000035945 sensitivity Effects 0.000 description 6
- 238000010586 diagram Methods 0.000 description 5
- 238000001514 detection method Methods 0.000 description 4
- 230000000694 effects Effects 0.000 description 4
- 238000004519 manufacturing process Methods 0.000 description 3
- 239000002245 particle Substances 0.000 description 3
- 230000004044 response Effects 0.000 description 3
- 229910004298 SiO 2 Inorganic materials 0.000 description 2
- 230000002542 deteriorative effect Effects 0.000 description 2
- 239000000446 fuel Substances 0.000 description 2
- 238000002347 injection Methods 0.000 description 2
- 239000007924 injection Substances 0.000 description 2
- 230000004043 responsiveness Effects 0.000 description 2
- 230000006866 deterioration Effects 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 239000007788 liquid Substances 0.000 description 1
- 230000002787 reinforcement Effects 0.000 description 1
- 238000007740 vapor deposition Methods 0.000 description 1
Landscapes
- Measuring Volume Flow (AREA)
Description
【発明の詳細な説明】
〔産業上の利用分野〕
本発明は膜式抵抗を有する直熱型流量センサ、
たとえば内燃機関の吸入空気量を検出するための
空気流量センサに関する。[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a direct heating type flow sensor having a membrane resistor,
For example, the present invention relates to an air flow sensor for detecting the intake air amount of an internal combustion engine.
一般に、電子制御式内燃機関においては、基本
燃料噴射量、基本点火時期等の制御のために機関
の吸入空気量は重要な運転状態パラメータの１つ
である。従来、このような吸入空気量を検出する
ための空気流量センサ（エアフローメータとも言
う）はベーン式のものが主流であつたが、最近、
小型、応答性が良い等の利点を有する温度依存抵
抗を用いた熱式ものが実用化されている。
Generally, in an electronically controlled internal combustion engine, the intake air amount of the engine is one of the important operating state parameters for controlling the basic fuel injection amount, basic ignition timing, and the like. Conventionally, vane-type air flow sensors (also called air flow meters) have been the mainstream for detecting the amount of intake air, but recently,
A thermal type using a temperature-dependent resistor has been put into practical use, and has the advantages of being small and having good response.
さらに、温度依存抵抗を有する空気流量センサ
としては、傍熱型と直熱型とがある。たとえば、
傍熱型の空気流量センサは、機関の吸気通路に設
けられた発熱抵抗、およびその上流、下流側に設
けられた２つの温度依存抵抗を備えている。この
場合、上流側の温度依存抵抗は発熱抵抗による加
熱前の空気流の温度を検出するものであり、つま
り、外気温度補償用であり、また、下流側の温度
依存抵抗は加熱抵抗によつて加熱された空気流の
温度を検出する。これにより、下流側の温度依存
抵抗と上流側の温度依存抵抗との温度差が一定に
なるように発熱抵抗の電流値をフイードバツク制
御し、発熱抵抗に印加される電圧により空気流量
（質量）を検出するものである。なお、上流側の
外気温度補償用温度依存抵抗を削除し、下流側の
温度依存抵抗の温度が一定になるように発熱抵抗
を制御すると、体積容量としての空気流量が検出
できる。（参照：特公昭54−9662号公報）。他方、
傍熱型に比べて応答速度が早い直熱型の空気流量
センサは、機関の吸気通路に設けられた温度検出
兼用の発熱抵抗、およびその上流側に設けられた
温度依存抵抗を備えている。この場合、傍熱型と
同様に、上流側の温度依存抵抗は発熱抵抗による
加熱前の空気流の温度を検出するものであり、つ
まり、外気温度補償用である。これにより、発熱
抵抗とその上流側の温度依存抵抗との温度差が一
定になるように発熱抵抗の電流値をフイードバツ
ク制御し、発熱抵抗に印加される電圧により空気
流量（質量）を検出するものである。なお、この
場合にも、外気温度補償用温度依存抵抗を削除
し、発熱抵抗の温度が一定になるように発熱抵抗
を制御すると、体積容量としての空気容量が検出
できる。 Furthermore, there are two types of air flow rate sensors having temperature-dependent resistance: indirect heating type and direct heating type. for example,
The indirectly heated air flow sensor includes a heat generating resistor provided in the intake passage of the engine, and two temperature dependent resistors provided upstream and downstream thereof. In this case, the temperature-dependent resistance on the upstream side detects the temperature of the air flow before heating by the heating resistor, that is, it is for outdoor temperature compensation, and the temperature-dependent resistance on the downstream side detects the temperature of the air flow before heating by the heating resistor. Detects the temperature of the heated air stream. As a result, the current value of the heating resistor is feedback-controlled so that the temperature difference between the temperature-dependent resistance on the downstream side and the temperature-dependent resistance on the upstream side is constant, and the air flow rate (mass) is controlled by the voltage applied to the heating resistor. It is something to detect. Note that if the temperature-dependent resistance for compensating the outside air temperature on the upstream side is deleted and the heating resistor is controlled so that the temperature of the temperature-dependent resistance on the downstream side is constant, the air flow rate as a volumetric capacity can be detected. (Reference: Special Publication No. 54-9662). On the other hand,
A directly heated air flow sensor, which has a faster response speed than an indirectly heated type, includes a heat generating resistor that is provided in the intake passage of the engine and also serves as temperature detection, and a temperature dependent resistor that is provided upstream of the heat generating resistor. In this case, similarly to the indirect heating type, the upstream temperature-dependent resistance detects the temperature of the air flow before being heated by the heating resistor, that is, it is used for outdoor temperature compensation. This allows feedback control of the current value of the heating resistor so that the temperature difference between the heating resistor and the temperature-dependent resistor upstream thereof remains constant, and detects the air flow rate (mass) based on the voltage applied to the heating resistor. It is. In this case as well, if the temperature-dependent resistance for compensating the outside air temperature is deleted and the heating resistor is controlled so that the temperature of the heating resistor is constant, the air capacity as the volumetric capacity can be detected.
直熱型空気流量センサは、上述の膜式抵抗を基
板たとえばシリコン単結晶基板の一面に形成し、
その基板をダクト内に収納することにより構成さ
れている。このような直熱型空気流量センサの出
力感度は、膜式抵抗から基板を介してダクトに逃
げる熱量と膜式抵抗から空気流に逃げる熱量との
割合に依存する。つまり、膜式抵抗から空気流へ
逃げる熱量割合が小さいと、膜視抵抗の発熱量の
センサ出力への寄与率が低下してセンサの出力感
度が低下する。 A directly heated air flow sensor has the above-mentioned film resistor formed on one side of a substrate such as a silicon single crystal substrate,
It is constructed by storing the substrate in a duct. The output sensitivity of such a directly heated air flow sensor depends on the ratio of the amount of heat escaping from the film resistor to the duct via the substrate and the amount of heat escaping from the film resistor to the air flow. In other words, if the proportion of heat escaping from the membrane resistor to the air flow is small, the contribution rate of the calorific value of the membrane resistor to the sensor output decreases, and the output sensitivity of the sensor decreases.
しかしながら、今まで提案されている直熱型空
気流量センサにおいては、膜式抵抗の発熱部兼温
度検知部分に対応する基板の反対側の面の部分が
平面構造であるので、膜式抵抗から空気流へ逃げ
る熱量は比較的小さく、従つて、センサの出力感
度が比較的低いという問題点がある。
However, in the directly heated air flow sensors that have been proposed so far, the part on the opposite side of the substrate that corresponds to the heat generating part and temperature sensing part of the film resistor has a flat structure. The problem is that the amount of heat escaping into the flow is relatively small, and therefore the output sensitivity of the sensor is relatively low.
本発明の目的は出力感度が高い直熱型流量セン
サを提供することであり、その手段は、膜式抵抗
の発熱部兼温度検知部分に対応する基板の反対側
の面の部分を凹凸構造にしたことである。
An object of the present invention is to provide a directly heated flow rate sensor with high output sensitivity, and its means are such that the opposite surface of the substrate corresponding to the heat generating part and temperature sensing part of the film resistor is made into an uneven structure. That's what I did.
上述の手段によれば、発熱部兼温度検知部に対
する空気流への放熱面積が大きくなり、この結
果、膜式抵抗から空気流へ逃げる熱量割合が大き
くなり、膜式抵抗の発熱量のセンサ出力への寄与
率が向上してセンサの出力感度が向上する。
According to the above-mentioned means, the heat dissipation area to the air flow from the heat generating part and temperature detection part becomes large, and as a result, the proportion of heat escaping from the film resistor to the air flow increases, and the sensor output of the heat value of the film resistor increases. The contribution rate to this increases, and the output sensitivity of the sensor improves.
以下、図面により本発明の実施例を説明する。 Embodiments of the present invention will be described below with reference to the drawings.
第５図は本発明に係る膜式抵抗を有する直熱型
空気流量センサが適用された内燃機関を示す全体
概要図、第６図、第７図は第５図のセンサ部分の
拡大縦断面図および横断面図である。第５図〜第
７図において、内燃機関１の吸気通路２にはエア
クリーナ３および整流格子４を介して空気が吸入
される。この吸気通路２内に計測管（ダクト）５
が設けられ、その内部に空気量を計測するための
発熱ヒータ兼用温度依存抵抗（膜式抵抗）６が設
けられている。膜式抵抗６はステイ７に固定さ
れ、ステイ７の外側に設けられた外気温度補償を
行う温度依存抵抗８と共に、ハイブリツド基板に
形成されたセンサ回路９に接続されている。 FIG. 5 is an overall schematic diagram showing an internal combustion engine to which a directly heated air flow sensor having a membrane resistor according to the present invention is applied, and FIGS. 6 and 7 are enlarged vertical cross-sectional views of the sensor portion in FIG. 5. and a cross-sectional view. 5 to 7, air is taken into an intake passage 2 of an internal combustion engine 1 via an air cleaner 3 and a rectifying grid 4. As shown in FIGS. A measuring pipe (duct) 5 is installed inside this intake passage 2.
A temperature dependent resistor (film type resistor) 6 which also serves as a heat generating heater is provided inside the resistor for measuring the amount of air. The film resistor 6 is fixed to the stay 7, and is connected to a sensor circuit 9 formed on a hybrid substrate together with a temperature dependent resistor 8 provided outside the stay 7 for compensating for the outside temperature.
センサ回路９は外気温度に対して膜式抵抗６の
温度が一定になるように該抵抗６の発熱量をフイ
ードバツク制御し、そのセンサ出力V0を制御回
路１０に供給する。制御回路１０はたとえばマイ
クロコンピユータによつて構成され、燃料噴射弁
１１の制御等を行うものである。 The sensor circuit 9 performs feedback control on the amount of heat generated by the film resistor 6 so that the temperature of the film resistor 6 is constant with respect to the outside air temperature, and supplies the sensor output V 0 to the control circuit 10 . The control circuit 10 is composed of, for example, a microcomputer, and controls the fuel injection valve 11 and the like.
センサ回路９は、第８図に示すごとく、膜式抵
抗６、温度依存抵抗８とブリツジ回路を構成する
抵抗９１，９２、比較器９３、比較器９３の出力
によつて制御されるトランジスタ９４、電圧バツ
フア９５により構成される。つまり、空気流量が
増加して膜式抵抗６（この場合、サーミスタ）の
温度が低下し、この結果、膜式抵抗６の抵抗値が
下降してV1＜VRとなると、比較器９３の出力に
よつてトランジスタ９４の導電率が増加する。従
つて、膜式抵抗６の発熱量が増加し、同時に、ト
ランジスタ９４のコレクタ電位すなわち電圧バツ
フア９５の出力電圧VQは上昇する。逆に、空気
流量が減少して膜式抵抗６の温度が上昇すると、
膜式抵抗６の抵抗値が増加してV1＞VRとなり、
比較器９３の出力によつてトランジスタ９４の導
電率が減少する。従つて、膜式抵抗６の発熱量が
減少し、同時に、電圧バツフア９５の出力電圧
VQは低下する。このようにして、膜式抵抗６の
温度は外気温度によつて定まる値になるようにフ
イードバツク制御され、出力電圧VQは空気流量
を示すことになる。 As shown in FIG. 8, the sensor circuit 9 includes a film resistor 6, a temperature-dependent resistor 8, resistors 91 and 92 forming a bridge circuit, a comparator 93, a transistor 94 controlled by the output of the comparator 93, It is composed of a voltage buffer 95. In other words, the air flow rate increases and the temperature of the membrane resistor 6 (thermistor in this case) decreases, and as a result, the resistance value of the membrane resistor 6 decreases and when V 1 < V R , the comparator 93 The output increases the conductivity of transistor 94. Therefore, the amount of heat generated by the film resistor 6 increases, and at the same time, the collector potential of the transistor 94, that is, the output voltage VQ of the voltage buffer 95 increases. Conversely, when the air flow rate decreases and the temperature of the membrane resistor 6 increases,
The resistance value of the membrane resistor 6 increases and becomes V 1 > V R ,
The output of comparator 93 causes the conductivity of transistor 94 to decrease. Therefore, the amount of heat generated by the membrane resistor 6 decreases, and at the same time, the output voltage of the voltage buffer 95 decreases.
V Q decreases. In this way, the temperature of the membrane resistor 6 is feedback-controlled to a value determined by the outside air temperature, and the output voltage VQ indicates the air flow rate.
第１Ａ図は本発明の第１の実施例としての膜式
抵抗６の一例を示し、第１Ｂ図、第１Ｃ図は、そ
れぞれ、第１Ａ図のＢ−Ｂ線，Ｃ−Ｃ線の断面図
である。第１Ａ図に示すように、たとえば200〜
400μm厚のシリコン単結晶基板６１上に図示しな
い絶縁膜たとえばSiO2を介して蒸着およびびエ
ツチツグにより温度依存抵抗パターン６２を形成
し、そのうち、点線枠内で示す部分６２ａが発熱
部兼温度検知部として作用する。 FIG. 1A shows an example of a film resistor 6 as a first embodiment of the present invention, and FIGS. 1B and 1C are cross-sectional views taken along line B-B and line C-C in FIG. 1A, respectively. It is. As shown in Figure 1A, for example, 200~
A temperature-dependent resistance pattern 62 is formed on a silicon single crystal substrate 61 with a thickness of 400 μm by vapor deposition and etching via an insulating film (not shown), such as SiO 2 , of which a portion 62a shown within the dotted line frame serves as a heat generating portion and a temperature sensing portion. It acts as.
本発明によれば、発熱部兼温度検知部６２ａに
対応する基板６１の裏面部分６１ａを凹凸構造に
し、放熱面積を大きくしてある。このような凹凸
構造はたとえばリブ状形状であり、これは、後述
のごとく、シリコン単結晶基板６１の異方性エツ
チングによつて得られる。これにより、発熱部兼
温度検知部６２からの熱が基板６１を介して空気
流に流れる割合を大きくしてある。この結果、膜
式抵抗６の発熱量のセンサ出力への寄与率が向上
する。 According to the present invention, the back surface portion 61a of the substrate 61 corresponding to the heat generating portion/temperature sensing portion 62a has an uneven structure to increase the heat dissipation area. Such an uneven structure has a rib-like shape, for example, and is obtained by anisotropic etching of the silicon single crystal substrate 61, as will be described later. This increases the rate at which heat from the heat generating section/temperature sensing section 62 flows into the air stream via the substrate 61. As a result, the contribution rate of the amount of heat generated by the film resistor 6 to the sensor output is improved.
なお、第１Ａ図〜第1C図に示す実施例におい
ては、基板６１の凹凸構造６１ａが空気流の方向
に平行に配置されているために、浮遊粒子の基板
６１の凹凸構造６１ａのよどみ部分への沈着防止
され、空気流量センサの応答性劣化を防止する効
果がある。 In the embodiment shown in FIGS. 1A to 1C, since the concavo-convex structure 61a of the substrate 61 is arranged parallel to the direction of the air flow, floating particles are transferred to the stagnation portions of the concave-convex structure 61a of the substrate 61. This has the effect of preventing the deterioration of the response of the air flow sensor.
第２Ａ図は本発明の第２の実施例としての膜式
抵抗６の他の例を示し、第２Ｂ図、第２Ｃ図は、
それぞれ、第２Ａ図のＢ−Ｂ線、Ｃ−Ｃ線の断面
図である。第２Ａ図〜第２Ｃ図に示す実施例にお
いては、基板６１の凹凸構造６１a′が空気流の方
向に垂直に配置されている。従つて、第１の実施
例に比べて、浮遊粒子が基板６１の凹凸構造６１
a′のよどみ部分へ沈着し易くなるという欠点はあ
るが、空気流の乱れにより凹凸構造６１a′近傍に
おける境界層が小さくなり、この結果、その分、
熱放散量が大きくなる。従つて、やはり、空気流
量センサの応答性劣化を防止できる。 FIG. 2A shows another example of the film resistor 6 as the second embodiment of the present invention, and FIGS. 2B and 2C show the following:
They are sectional views taken along line BB and line CC in FIG. 2A, respectively. In the embodiment shown in FIGS. 2A to 2C, the uneven structure 61a' of the substrate 61 is arranged perpendicular to the direction of the air flow. Therefore, compared to the first embodiment, the floating particles are caused by the concavo-convex structure 61 of the substrate 61.
Although there is a disadvantage that it becomes easier to deposit in the stagnation part of a', the boundary layer near the uneven structure 61a' becomes smaller due to the turbulence of the air flow, and as a result,
Heat dissipation increases. Therefore, it is possible to prevent the responsiveness of the air flow sensor from deteriorating.
また、第１の実施例では、発熱部兼温度検知部
６２ａにおけるシリコン基板６１の厚さは、第１
Ｂ図、第１Ｃ図に示すごとく、非常に薄くしてあ
り、これにより、そのヒートマスを小さくせしめ
ているが、第２の実施例では、発熱部兼温度検知
部６２ａと基板６１の保持部との間にリブ構造６
１ｂ，６１ｃを設けて補強してある。このリブ構
造６１ｂ，６１ｃは凹凸構造６１a′と同時にシリ
コン単結晶基板６１の異方性エツチングによつて
得ることができる。 Further, in the first embodiment, the thickness of the silicon substrate 61 in the heat generating part/temperature sensing part 62a is the same as that of the first embodiment.
As shown in FIG. B and FIG. 1C, the heat mass is made very thin, which reduces the heat mass. Rib structure between 6
1b and 61c are provided for reinforcement. The rib structures 61b and 61c can be obtained by anisotropic etching of the silicon single crystal substrate 61 at the same time as the uneven structure 61a'.
第３Ａ図は本発明の第３の実施例としての膜式
抵抗６の他の例を示し、第３Ｂ図、第３Ｃ図は、
それぞれ、第３Ａ図のＢ−Ｂ線，Ｃ−Ｃ線の断面
図である。第３Ａ図〜第３Ｃ図に示す実施例にお
いては、基板６１の凹凸構造６１a″は四角錘を格
子状に配列したものである。従つて、第１の実施
例と同様に、浮遊粒子が基板６１の凹凸構造６１
a″のよどみ部分へ沈着しにくく、しかも、第２の
実施例と同様に、空気流の乱れにより凹凸構造６
１a″近傍における境界層が小さくなり、この結
果、熱放散量がより大きくなる。従つて、空気流
量センサの応答性劣化を防止できる。 FIG. 3A shows another example of the film resistor 6 as the third embodiment of the present invention, and FIGS. 3B and 3C show the following:
They are sectional views taken along line BB and line CC in FIG. 3A, respectively. In the embodiment shown in FIGS. 3A to 3C, the concavo-convex structure 61a'' of the substrate 61 is formed by arranging square pyramids in a lattice pattern. Therefore, as in the first embodiment, floating particles are 61 uneven structure 61
It is difficult to deposit in the stagnation part of a'', and like the second embodiment, the uneven structure 6
The boundary layer in the vicinity of 1a'' becomes smaller, and as a result, the amount of heat dissipated becomes larger.Therefore, it is possible to prevent the responsiveness of the air flow sensor from deteriorating.
なお、第４の実施例では、四角錘を格子状に配
列してあるが、多角錘を格子状に配列してもよ
い。 In the fourth embodiment, the square pyramids are arranged in a grid pattern, but polygonal pyramids may be arranged in a grid pattern.
第４図は第４の実施例としての膜式抵抗６の部
分断面図である。第１，第２，第３の実施例にお
いては、凹凸構造６１ａ，６１a′，６１a″の断面
形状が三角波状であつたが、第４の実施例におい
ては、三角波状の各谷部分平面状にしてある。こ
のような凹凸構造を第１，第２、第３の実施例に
適用しても同様の効果が期待できる。 FIG. 4 is a partial sectional view of a film resistor 6 as a fourth embodiment. In the first, second, and third embodiments, the cross-sectional shape of the uneven structures 61a, 61a', and 61a'' was a triangular wave shape, but in the fourth embodiment, each valley portion of the triangular wave shape is planar. Similar effects can be expected even if such an uneven structure is applied to the first, second, and third embodiments.
次に、第１Ａ図〜第１Ｃ図の基板６１の製造工
程について第９図を参照して説明する。なお、第
９図の各図は第１Ｃ図の断面図に対応する。 Next, the manufacturing process of the substrate 61 shown in FIGS. 1A to 1C will be explained with reference to FIG. 9. In addition, each figure of FIG. 9 corresponds to the sectional view of FIG. 1C.
始めに、第９図Ａに示すようなシリコン単結晶
６１を準備する。この場合、矢印Ａで示す面は１
００もしくは１１０面である。次に、第９図Ｂに
示すように、保持部を形成するために、SiO2も
しくはSi3N4のエツチング保護膜８１を施し、異
方性エツチングを行うと、第９図ｃ示す形状が得
られる。ここで、矢印Ｂで示す面は１１１面であ
る。すなわち、異方性エツチングとは、シリコン
単結晶の１１１面のエツチング速度が他の面たと
えば１００もしくは１１０面のエツチング速度に
比して著しく小さいというエツチング速度の相違
を利用して行つているものである。 First, a silicon single crystal 61 as shown in FIG. 9A is prepared. In this case, the surface indicated by arrow A is 1
00 or 110 sides. Next, as shown in FIG. 9B, an etching protection film 81 of SiO 2 or Si 3 N 4 is applied to form a holding portion, and anisotropic etching is performed to form the shape shown in FIG. 9C. can get. Here, the surface indicated by arrow B is the 111th surface. In other words, anisotropic etching is carried out by taking advantage of the difference in etching rate in which the etching rate of the 111 plane of a silicon single crystal is significantly lower than that of other planes, such as the 100 or 110 plane. be.
次いで、第９図Ｄに示すごとく、エツチング保
護膜７１を除去し、再び第９図Ｅに示すごとく、
別のエツチング保護膜８２を施す。そして、再び
異方性エツチングを行うと、第９図Ｆに示す形状
が得られ、エツチング保護膜８２を除去すると、
第９図Ｇに示す最終形状が得られる。つまり、放
熱面積を増大する凹凸構造６１ａが得られること
になる。 Next, as shown in FIG. 9D, the etching protection film 71 is removed, and as shown in FIG. 9E again,
Another etching protection film 82 is applied. Then, when anisotropic etching is performed again, the shape shown in FIG. 9F is obtained, and when the etching protection film 82 is removed,
The final shape shown in FIG. 9G is obtained. In other words, the uneven structure 61a that increases the heat dissipation area is obtained.
同様な製造工程により第２Ａ図〜第２Ｃ図に示
す凹凸構造６１a′、リブ構造６１ｂ，６１ｃ、お
よび第３Ａ図〜第３Ｃ図に示す凹凸構造６２a″が
得られる。 Through similar manufacturing steps, the uneven structure 61a' shown in FIGS. 2A to 2C, the rib structures 61b and 61c, and the uneven structure 62a'' shown in FIGS. 3A to 3C are obtained.
なお、上述の異方性エツチングでは、Siの基本
的に面方位として、１００，１１０，１１１を示
したが、他の面方位をエツチングに露出させるこ
とにより、６角錘、８角錘等の多角錘を製造でき
る。 In addition, in the above-mentioned anisotropic etching, the plane orientations of Si are basically 100, 110, and 111, but by exposing other plane orientations to the etching, it is possible to obtain hexagonal pyramids, octagonal pyramids, etc. Polygonal pyramids can be manufactured.
このように、本発明の実施例においては、異方
性エツチングを利用して放熱面積増大のための凹
凸構造を得ている。 As described above, in the embodiment of the present invention, anisotropic etching is utilized to obtain a concavo-convex structure for increasing the heat dissipation area.
なお、上述の実施例においては、基板上に発熱
部兼温度検知部としての温度依存抵抗を形成して
いるが、この代りに、基板内に拡散抵抗を形成し
てもよい。また、本発明は空気流量センサ以外の
流量センサたとえば液体流量センサにも適用し得
る。 In the above-described embodiment, a temperature-dependent resistor is formed on the substrate as a heat generating section and a temperature detecting section, but instead of this, a diffused resistor may be formed within the substrate. Further, the present invention can be applied to flow rate sensors other than air flow rate sensors, such as liquid flow rate sensors.
以上説明したように本発明によれば、発熱部兼
温度検知部に対する空気流への放熱面積を大きく
でき、この結果、膜式抵抗から空気流へ逃げる熱
量割合が大きくでき、膜式抵抗の発熱量のセンサ
出力への寄与率が向上してセンサの出力感度を向
上できる。
As explained above, according to the present invention, it is possible to increase the heat dissipation area of the heat generating part/temperature detection part to the air flow, and as a result, the proportion of heat escaping from the film resistor to the air flow can be increased, and the heat generated by the film resistor can be increased. The contribution rate of the quantity to the sensor output is improved, and the output sensitivity of the sensor can be improved.
第１Ａ図は本発明の第１の実施例としての膜式
抵抗を示す平面図、第１Ｂ図、第１Ｃ図は、それ
ぞれ、第１Ａ図のＢ−Ｂ線，Ｃ−Ｃ線の断面図、
第２Ａ図は本発明の第２の実施例としての膜式抵
抗を示す平面図、第２Ｂ図、第２Ｃ図は、それぞ
れ、第２Ａ図のＢ−Ｂ線、Ｃ−Ｃ線の断面図、第
３Ａ図は本発明の第３の実施例としての膜式抵抗
を示す平面図、第３Ｂ図、第３Ｃ図は、それぞ
れ、第３Ａ図のＢ−Ｂ線、Ｃ−Ｃ線の断面図、第
４図は本発明の第４の実施例としての膜式抵抗を
示す平面図、第５図は本発明に係る膜式抵抗を有
する直熱型空気流量センサが適用された内燃機関
を示す全体概要図、第６図、第７図は第４図のセ
ンサ部分の縦断面図および横断面図、第８図は第
５図のセンサ回路の回路図、第９図は第１Ａ図〜
第１Ｃ図の基板の製造工程を説明するための図、
である。
１……内燃機関、２……吸気通路、５……計測
管（ダクト）、６……膜式抵抗、９……センサ回
路、１０……制御回路、６１……基板、６１ａ，
６１a′……凹凸構造、６１ｂ，６１ｃ……リブ構
造、６２……温度依存抵抗パターン、６２ａ……
発熱部兼温度検知部。
FIG. 1A is a plan view showing a membrane resistor as a first embodiment of the present invention, FIGS. 1B and 1C are cross-sectional views taken along line B-B and line C-C in FIG. 1A, respectively.
FIG. 2A is a plan view showing a membrane resistor as a second embodiment of the present invention, and FIGS. 2B and 2C are cross-sectional views taken along line BB and C-C in FIG. 2A, respectively. FIG. 3A is a plan view showing a membrane resistor as a third embodiment of the present invention, and FIGS. 3B and 3C are cross-sectional views taken along line B-B and line C-C in FIG. 3A, respectively. FIG. 4 is a plan view showing a membrane resistor as a fourth embodiment of the present invention, and FIG. 5 is an overall diagram showing an internal combustion engine to which a directly heated air flow sensor having a membrane resistor according to the present invention is applied. 6 and 7 are longitudinal and cross sectional views of the sensor portion in FIG. 4, FIG. 8 is a circuit diagram of the sensor circuit in FIG. 5, and FIG. 9 is a diagram of the sensor circuit in FIG.
A diagram for explaining the manufacturing process of the substrate in FIG. 1C,
It is. DESCRIPTION OF SYMBOLS 1... Internal combustion engine, 2... Intake passage, 5... Measuring tube (duct), 6... Film resistance, 9... Sensor circuit, 10... Control circuit, 61... Board, 61a,
61a'... uneven structure, 61b, 61c... rib structure, 62... temperature dependent resistance pattern, 62a...
Heat generating part and temperature detection part.
Claims (1)
ダクト内に収納した直熱型流量センサにおいて、
前記膜式抵抗の発熱部兼温度検知部分に対応する
前記基板の他の面の部分を凹凸構造にしたことを
特徴とする直熱型流量センサ。 ２ 前記基板がシリコン単結晶であり、該シリコ
ン単結晶を異方性エツチングにより前記凹凸構造
を形成した特許請求の範囲第１項に記載の直熱型
流量センサ。 ３ 前記凹凸構造が流体の流れ方向に平行である
特許請求の範囲第１項に記載の直熱型空気流量セ
ンサ。 ４ 前記凹凸構造が流体の流れ方向に垂直である
特許請求の範囲第１項に記載の直熱型流量セン
サ。 ５ 前記凹凸構造が、多角錘の凸部を格子状に配
列することによつて得られる特許請求の範囲第１
項に記載の流量センサ。[Claims] 1. A direct heating type flow sensor in which a film resistor is formed on one surface of a substrate, and the substrate is housed in a duct,
A directly heated flow rate sensor characterized in that a portion of the other surface of the substrate corresponding to the heat generating portion and temperature sensing portion of the film resistor has an uneven structure. 2. The direct heating type flow sensor according to claim 1, wherein the substrate is a silicon single crystal, and the uneven structure is formed by anisotropic etching of the silicon single crystal. 3. The directly heated air flow sensor according to claim 1, wherein the uneven structure is parallel to the fluid flow direction. 4. The directly heated flow rate sensor according to claim 1, wherein the uneven structure is perpendicular to the fluid flow direction. 5. Claim 1, wherein the uneven structure is obtained by arranging the convex portions of a polygonal pyramid in a lattice shape.
Flow rate sensor described in section.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP60025233A JPS61186820A (en) | 1985-02-14 | 1985-02-14 | Directly heated flow rate sensor |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP60025233A JPS61186820A (en) | 1985-02-14 | 1985-02-14 | Directly heated flow rate sensor |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS61186820A JPS61186820A (en) | 1986-08-20 |
| JPH0441765B2 true JPH0441765B2 (en) | 1992-07-09 |
Family
ID=12160256
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP60025233A Granted JPS61186820A (en) | 1985-02-14 | 1985-02-14 | Directly heated flow rate sensor |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS61186820A (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE19857549B4 (en) * | 1998-12-14 | 2009-12-24 | Robert Bosch Gmbh | Sensor with a membrane and method of making the sensor with a membrane |
| JP7510737B1 (en) | 2024-03-19 | 2024-07-04 | 東フロコーポレーション株式会社 | Thermal Flow Meter |
-
1985
- 1985-02-14 JP JP60025233A patent/JPS61186820A/en active Granted
Also Published As
| Publication number | Publication date |
|---|---|
| JPS61186820A (en) | 1986-08-20 |
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